How To Increase Your Metabolism

Tyler Bramlett Body Weight Flow

Bodyweight Flow is a brand new fitness course developed by Tyler Bramlett and Sylvia Favela which comes with seven different flow routines for upper body, lower body and full body. There are seven routines in the beginner, intermediate and advanced levels of each of these areas of the body. Each suggested routine includes an upper body flow, lower body flow, and full body flow to practice, with a 1 minute rest in between each exercise. There are also 14 different suggested routines for 20 minutes and 30 minutes. And of course, you simply choose between the beginner, intermediate, or advanced routine depending on where you are. BodyWeight Flow program bonuses include daily flow calendar to track the progress of daily exercise routines. Exercise pairing guide includes general exercise, yoga moves, and power lifter moves. Many more routines are given as a bonus with the manuals to try achieving even better results. The Body Weight Flow program is a complete system designed to burn more calories which can also be used with any workouts. Read more here...

Bodyweight Flow Overview

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Metabolic rate and ecology

The investigation of metabolic rate variation, and the gas exchange patterns that support it, are among the most venerable pursuits in environmental physiology. Yet, at least in insects, there is much that remains controversial. In particular, the scaling exponents of metabolic rate during rest, pedestrian locomotion, and flight are not well resolved. It is not known whether the intraspecific and interspecific exponents differ consistently, nor whether phylogenetic non-independence has a large effect on the latter. Likewise, it is not entirely clear why insects at rest show discontinuous gas exchange, nor whether characteristics of the DGC, or for that matter metabolic rates, always show high repeatability. What is clear, though, is that a sound comprehension of metabolic rate variation is essential for understanding the ecology and evolution of insects. Metabolic rate variation not only influences the abundance and distribution of insects (Chown and Gaston 1999), but it probably also...

Factors Affecting Metabolic Rate

One of the most important factors that affects metabolic rate is the temperature of the organism, since within limits all chemical reactions of metabolism proceed faster at higher temperatures. The internal temperature of most invertebrate an imals, fish, and amphibians is the same as the temperature of the environment in which they live. Such organisms are called poikilotherms. In poikilothermic organisms, metabolic rate increases as the environmental temperature increases. Such organisms move slowly and grow slowly when the temperature is cold, since their metabolic rate is very low at cold temperatures. To compare the metabolic rates of different poiki-lotherms, one must measure their rate of metabolism under standard conditions. Standard metabolism is usually defined as the rate of energy use when the animal is resting quietly, twelve hours after the last meal, and is at a temperature of 30 degrees Celsius however, for small invertebrates, protists, and bacteria, only temperature...

Metabolic rate variation temperature and water availability

Temperature and water availability are both thought to influence metabolic rate, especially over the longer term, resulting in adaptations that apparently reflect the need either for water conservation or starvation resistance, or the response to low environmental temperatures (Chown and Gaston 1999). The influence of temperature on metabolic rate over short timescales has been called the most overconfirmed fact in insect physiology (Keister and Buck 1964), and acute modifications of metabolic rate by temperature are certainly widely known for insects, with many modern studies continuing to document them. The short-term influence of humidity on metabolic rates has also been documented in several species, though with the advent of flow-through respirometry these effects are often not investigated, largely because rate measurements are made in dry air for technical reasons. In at least some instances, increases in metabolic rate with declining humidity may be the result of increased...

Metabolic rate variation size

Discontinuous gas exchange in ticks is thought to be one of the ways in which these animals maintain the very low metabolic rates required by their sit-and-wait strategy, which includes long periods of fasting (Lighton and Fielden 1995). Scorpions are also thought to have uncharacteristically low metabolic rates, and this has prompted considerable speculation regarding the benefits of low metabolic rates in both groups (Lighton et al. 2001). In turn, this speculation has raised the question of what a 'characteristic' metabolic rate is for arthropods, including insects, of a given size. In other words, what values should the coefficient (c) and exponent (z) assume in the scaling relationship where B is metabolic rate (usually expressed in mW) and M is body mass (usually expressed in g). This question has long occupied physiologists and ecologists, and can indeed be considered one of the most contentious, yet basic issues in environmental physiology. The controversy concerns both the...

Basal metabolic rates of endotherms are related to body size

Obviously, the total basal metabolic rate of an elephant is greater than that of a mouse. After all, the elephant is more than 100,000 times more massive than the mouse. However, the metabolic rate of the elephant is only about 7,000 times greater than that of the mouse. That means that the metabolism of a gram of mouse tissue is much greater than the metabolism of a gram of elephant tissue more than 20 times greater (Figure 41.13). Across all of the endotherms, basal metabolic rate per gram of tissue increases as animals get smaller. Why should this be so No one actually knows. It was once thought that the reason was that as animals get bigger, they have a smaller ratio of surface area to volume (see Figure 4.3). Since heat production is related to the volume, or mass, of the animal, but its capacity to dissipate heat is related to its surface area, it was proposed that larger animals evolved lower metabolic rates to avoid overheating. This explanation is not sufficient for several...

Pathways in the coordination of cellular glucose and fat metabolism

Fatty Acid Beta Oxidation Cpt1

Current theory identifies two major biochemical pathways as central components of this integrated coordination of energy metabolism. These are the glucose-fatty acid cycle first described in 1963 (Randle et al., 1963) and the malonyl CoA carnitine palmitoyl transferase (CPT)-1 pathway which was suggested by the studies of McGarry and coworkers in the late 1970s (McGarry et al., 1977). Importantly, these two pathways complement each other (Fig. 2.1). The glucose-fatty acid cycle links carbohydrate and fat metabolism and was one of the first theories to describe how fatty acids influence glucose metabolism. It centres on the proposition that increased beta-oxidation (utilisation) of fatty acids in skeletal muscle results in a reduced uptake and oxidation of glucose (Fig. 2.1), offering additional fine-tuning to the 'coarse' control of glucose and fat utilisation that is enforced at whole body level, by insulin (Frayn, 2003). Although recent advances in the study of whole...

Polytrauma Metabolic Response

The metabolic response to injury is a physiological 'systemic inflammatory' reaction to tissue damage. It is a hormone-mediated defence response that establishes the optimum environment for wound control, debridement and subsequent repair. In some circumstances it may become prolonged or exaggerated. If control is lost, this may lead to a pathological systemic inflammatory response known 'host defence failure disease' or 'multi-organ failure'. This accounts for the third peak of the ATLS trimodal distribution of death following major trauma.

Gas exchange and metabolic rate during activity

Insects show tremendous scope for the increase of metabolic rates above resting levels. This is due mainly to the energetic demands of flight, which can be responsible for 100-fold increases in metabolic rate. Although many insects, such as ants and honeybees, might never experience levels of metabolism as low as SMRs measured under solitary conditions (sometimes including anaesthesia), and therefore have factorial aerobic scopes more in keeping with those of vertebrates (4-10) (Harrison and Fewell 2002), large moths such as those examined by Bartholomew and Casey (1978) are often quiescent. Therefore, factorial aerobic scopes of more than 100 (as high as 170) are likely to be accurate reflections of the increases in aerobic metabolism that are possible in insects. Such high aerobic scopes are of considerable interest not only because insects often make a rapid transition from alert rest to flight, but also because flight metabolic rate might also constrain resting levels of...

Gas exchange and metabolic rate at rest

Within a particular species, metabolic rates at rest vary over the course of development (Clarke 1957), during diapause (Denlinger et al. 1972), over the course of a day (Crozier 1979 Takahashi-Del-Bianco et al. 1992), between seasons (Davis et al. 2000), and as a consequence of changing temperature, water availability, and size. The latter variation is most interesting from an ecological perspective, and has consequently been the source of most controversy.

Patterns of Growth and Death

The type of dormant response depends on the plant's pattern of growth and death. Perennials are plants that live year after year, undergoing a period of dormancy during the cold season. In herbaceous species, the aboveground portions die, but the plants survive as specialized underground stems. Woody shrubs and trees remain alive above-ground. Deciduous species shed their leaves in winter, while many nondeciduous species, often called evergreens, keep their leaves year-round but dramatically reduce their metabolic rates.

Economic Growth and Modernization

The average weight gain after pregnancy is less than 1 kg although the range is wide. In many developing countries, consecutive pregnancies with short spacing often result in weight loss rather than weight gain. Menopausal women are particularly prone to rapid weight gain. This is primarily due to reductions in activity although loss of the menstrual cycle also affects food intake and reduces metabolic rate slightly.

Nonnuisance Nonmaleficence

From these studies we have learned that children have a different side effect profile with atypical neuroleptics as compared to adults, with more weight gain in smaller children and some adverse events related to high prolactin levels. In general the problem of weight gain for some of these second generation antipsychotic drugs increasingly seems to be a limiting factor of their use. The Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) study in adult patients with chronic schizophrenia (Lieberman et al. 2005) showed that treatment with Olanzapine was particularly associated with more discontinuation for weight gain or metabolic effects, whilst the use of first generation antipsychotics was associated with more discontinuation due to extra-pyramidal side effects. Olanzapine was superior to the other drugs with respect to treatment adherence. At present, there is controversy about the possible safety of atypical drugs because of their...

The Biosynthesis Of Fatty Acids

In contrast to simple diffusion, there is increasing evidence for protein-mediated transport. Of the various putative transport proteins, FABPs, fatty acid translocase (FAT) and fatty acid transport protein (FATP) have been identified in a variety of cell types. All three proteins are regulated to some degree by members of the PPAR (peroxisome pro-liferator-activated receptor) family of transcription factors. (The PPAR transcription factors are part of the steroid hormone receptor superfamily and affect many genes of lipid metabolism, Section 5.3.2.) Several isoforms of FABPs and FATPs are also regulated by insulin. Moreover, expression, regulation and activity of the various transport proteins can often (but not always) be correlated with increased fatty acid movements in animal models of fat metabolism such as in Ob (obese) mice mutants. Null mutants, e.g. for FAT, have also been created and these show abnormal fatty acid metabolism.

The Effects of Antipsychotic Medications on Weight

Antipsychotic medications have been the mainstay of treatment for schizophrenia for over half a century. A link between weight gain and treatment with chlorpromazine and other low-potency conventional anti-psychotic agents, such as thioridazine, was noted in early studies of the metabolic effects of these agents. (Bernstein 1988 Rockwell et al. 1983). A recent study by Allison et al. (1999b) based on 1989 National Health Interview Survey data revealed that a significantly greater proportion of female patients with schizophrenia had BMI distributions in the overweight and obese spectrum compared with their counterparts in the general medical population, with a trend toward greater BMI seen among male schizophrenic patients. This study is notable because the data are based on survey material collected in 1989, before the advent of the novel anti-psychotic medications. Thus, the results of that survey reflect obesity in a population of schizophrenic patients medicated with conventional...

Toxicological Applications Of Metabonomics

High-resolution XH NMR spectroscopic analysis of biofluids has proved to be one of the most powerful techniques for the investigation organism response to xenobiotics. Exposure of an organism to a xenobiotic results in subtle modifications in the biochemical composition of intra- and extracellular fluids as the organism attempts to maintain homeostasis (constancy of internal environment). This metabolic adjustment involves altering the composition of body fluids such as urine and plasma, and this change in biochemical composition can be rapidly profiled with XH NMR spectroscopic analysis. XH NMR spectral profiles of biofluids provide a unique fingerprint of the metabolic state of an organism, and can provide information on the nature of a drug or toxin to which an animal has been exposed 1,57,52-55 . The site or basic mechanism of toxicity can often be determined from characteristic changes in the concentrations and patterns of endogenous metabolites in biofluids (Figure 5.2). For...

Evolution of Toxic Lesions

Toxicological data are seldom straightforward with drugs that target multiple tissues rather than single organs and induce a time series of interrelated biochemical events. Since lesions develop and resolve in real time, time-related changes in NMR-detected metabolic profiles for each toxin must be taken into account, and indeed the time profile of altered biochemical composition is in itself a feature of the toxicity 5,56 (Figure 5.5A). Therefore, *H NMR spectra of biofluids represent complex indices of the metabolic response of an organism to xenobiotic exposure. The evolution of a toxin-induced lesion can be mapped with biochemical trajectory plots (as shown in Figure 5.5B), where the mean response of a group of animals to a particular xenobiotic at a given timepoint is expressed as a single coordinate in the PC map, and the coordinates are connected in chronological order to generate a trajectory that corresponds to the evolving metabolic status of the population 5 . The direction...

Inflammation and Immunity

The first time the immune system encounters a foreign antigen, its primary response is slow, and a disease may result from a pathogen's metabolic effects. Eventually, the immune response generates activated lymphocytes and antibodies that kill the bacteria or the virally infected cells to end the disease process. Memory lymphocytes are also produced that will respond against the same antigen if needed later. When the animal recovers, it will usually be immune to a second infection by the same disease-producing agent. The ability to resist a second infection is called immunological memory, and it may last for the life of the individual, as long as the memory lymphocytes live. Modern disease prevention techniques use immunizations to prevent the first experience of disease caused by a pathogen. In immunization, a

Colocalization Of Neurochemicals In Hcrt Neurons

Hcrt neurons contain several other neurotransmitters. Although the functional consequence of these additional neurotransmitters is not completely understood, phenotypic differences exist between the Hcrt ligand knockout mouse, in which only the Hcrt gene is deleted,16 and the transgenic Hcrt ataxin-3 mouse, in which Hcrt-expressing neurons degenerate.17 Although a narcolepsy-like syndrome is seen in both animals, hypophagia and obesity occur only in the Hcrt ataxin-3 mouse,17 suggesting that other factors in the Hcrt neurons contribute to regulation of energy metabolism.

Hormones Controlling Growth Development and Metabolism

Steroid hormones, also produced in the adrenal glands, stimulate the production of glucose from noncarbohydrate molecules (gluconeogenesis). The stimulus for this is prolonged stress, for example, starvation. These glucocorticoids, such as cortisol and corticosterone, evolved early and are very important in combating stresses resulting from migration among birds and even fish. The pancreatic hormones insulin and glucagon also effect energy metabolism. These two proteins regulate blood sugar, fat, and protein levels. After eating, insulin stimulates transport of these molecules into liver, fat, and muscle cells and then stimulates the incorporation of the simple molecules, such as glucose, amino acids, and fatty acids, into larger storage molecules, such as glycogen, protein, and fats. Glucagon has opposite actions. After a prolonged period without food intake, glucagon stimulates breakdown of complex molecules, such as glyco-gen and fats, into simple...

The Three Regions of the Intestinal Wall Are Supplied From a Common Set of Large Arterioles

Compared with other major organ vasculatures, the circulation of the small intestine has a poorly developed au-toregulatory response to locally decreased arterial pressure, and as a result, blood flow usually declines because resistance does not adequately decrease. However, elevation of venous pressure outside the intestine causes sustained myo-genic constriction, in this regard, the intestinal circulation equals or exceeds similar regulation in other organ systems. Intestinal motility has little effect on the overall intestinal blood flow, probably because the increases in metabolic rate are so small. In contrast, the intestinal blood flow increases in approximate proportion to the elevated metabolic rate during food absorption.

The Hepatic Circulation Is Perfused by Venous Blood From Gastrointestinal Organs and a Separate Arterial Supply

About half of the oxygen used by the liver is derived from venous blood, even though the splanchnic organs have removed one third to one half of the available oxygen. The hepatic arterial circulation provides additional oxygen. The liver tissue efficiently extracts oxygen from the blood. The liver has a high metabolic rate and is a large organ, consequently, it has the largest oxygen consumption of all organs in a resting person. The metabolic functions of the liver are discussed in Chapter 28.

Skeletal Muscle Circulation

The dominant mechanism controlling skeletal muscle resistance at rest is the sympathetic nervous system. Resting skeletal muscle has remarkably low oxygen consumption per 100 g of tissue, but its large mass makes its metabolic rate a major contributor to the total oxygen consumption in a resting person.

Skeletal Muscle Blood Flow and Metabolism Can Vary Over a Large Range

Skeletal muscle blood flow can increase 10- to 20-fold or more during the maximal vasodilation associated with high-performance aerobic exercise. Comparable increases in metabolic rate occur. Under such circumstances, total muscle blood flow may be equal to three or more times the resting cardiac output obviously, cardiac output must increase during exercise to maintain the normal to increased arterial pressure (see Chapter 30).

Risk Factors For Appetite Control

The tendency to gain weight is associated with a low basal metabolic rate, low energy cost of physical activity, a low capacity for fat oxidation (relatively high respiratory quotient RQ), high insulin sensitivity, low sympathetic nervous system activity and a low plasma leptin concentration. In the state of obesity itself many of these risk factors (or predictors of weight again) are reversed.

The Coagulation System And Diabetes Mellitus

Decreased activity of antithrombotic factors in blood can potentiate thrombosis. Of note, concentrations in blood of protein C and activity of antithrombin are decreased in diabetic subjects. Unlike changes in concentrations of prothrom-botic factors, altered concentrations and activity of antithrombotic factors appear to be reflections of the metabolic state typical of diabetes such as hyperglycemia, regardless of whether type 1 or type 2 diabetes is responsible. In fact, decreased antithrombotic activity has been associated with nonenzymatic glycation of anti-thrombin.

Summary cellular mechanisms involved in fatty aciddependent effects on insulin sensitivity

In summary, there are various mechanisms proposed to explain the biochemical pathways involved in the progressive development of dietary fat-induced insulin resistance (Fig. 2.2). Fatty acids seem able to modulate the intracellular metabolism of glucose either directly (e.g. glucose fatty acid cycle), or indirectly via their effects on the insulin signalling cascade and on insulin secretion. This cross-talk between glucose (and insulin) and fatty acids plays a vital role in the coordination of whole body and cellular energy metabolism. Fatty acid stimulation of insulin secretion ensures a heightened insulin response under conditions where the adverse effects of the glucose-fatty acid cycle would otherwise result in impaired glucose uptake and hyperglycaemia. However, under conditions of chronic over-provision (either via the diet or through excessive release into the circulation from adipose tissues stores as in obesity), excess fatty acids may lead to intracellular accumulation of LC...

Energy Expenditure At Rest

In general medicine and medical practice the interest in energy metabolism is often focused on basal metabolism. This is easy to understand because variations in basal metabolic rate (BMR) can be in the range of 30-40 . This variation can account for large increases and decreases in body weight, especially if they persist for a long period of time. The reason for the inter- but also intra-individual variations in BMR can only partly be explained by variations in active body mass mainly muscle About two-thirds of the energy expenditure over 24 hours amounts to the resting energy metabolism. New findings regarding the uncoupling protein can shed new light on BMR and might to some extent explain the variations in BMR between individuals and perhaps also changes in BMR with time and ageing.

Energy Expenditure During Exercise

One cannot apply strict mathematical principles to biological systems, but when analysing energy balance for longer periods of time, energy metabolism during and after exercise must be taken into account. It is obvious that both the intensity and the duration are the main determinants of energy expenditure during exercise. However, many factors may modify the energy expenditure for a given rate of work and the total cost for certain activities. For this reason it is difficult to give exact figures for the energy cost of exercise. Therefore the discussion of energy expenditure should be based on individual conditions and values given for certain activities or for groups of subjects are subject to large uncertainties. During short-term (a few minutes) hard dynamic muscular exercise carried out with large muscle groups, the energy metabolism may increase to 10-15 times the BMR in untrained subjects and 25-30 times the BMR in well-trained athletes from endurance events. However, due to...

FC Changes in Caveolae Effects of Signal Transduction

The metabolic effects of chronic changes in the FC content of the caveolae can be explained in terms of competition between binding of protein and binding of FC to overlapping sequences within a central (resides 82-101) domain of caveolin, However the content of FC in caveolae also responds both spatially and temporally to physiological changes at the cell surface, in particular to the binding of protein growth factors. Could these changing FC levels be involved in regulating the magnitude and duration of signal transduction and possibly, in the case of branching pathways, its selectivity

Functional Role Within the Feeding Circuitry

Major target for the arcuate nucleus, which focused on the neuroendocrine and autonomic response to starvation. However, the discovery of AGRP as a selective marker for arcuate nucleus NPY neurons also made it possible to map out the full extent of the projections emanating from these cells. By this approach it was demonstrated not only that the NPY and POMC neurons form almost completely parallel ascending pathways, but also that these extend well beyond the hypothalamus and include a wealth of structures, from the olfactory nuclei to the nucleus tractus solitarii.126 In this manner, the metabolic signals are in a position to directly engage numerous specialized assemblies of neurons to participate in the decision to feed or not to feed. Such a concept of distributed systems has been invoked in systems-oriented models of the regulation of feeding behaviour.127, 103,128,104 The circuitry can be compared to the basal ganglia, where incoming information has been proposed to disseminate...

Causes Of Insulin Resistance

Insulin resistance may be caused by rare genetic defects that alter insulin binding to its cellular receptors or cause defects in receptor or postreceptor signal trans-duction (1). Recently, defects in the nuclear receptor, PPARy, have also been linked to syndromes of severe insulin resistance (2). In addition, some endocrine-metabolic syndromes, such as Cushing's syndrome, acromegaly, and polycystic ovary syndrome, are associated with insulin resistance because of the hormonal imbalances associated with these conditions. However, in the most common forms of insulin resistance, single gene defects have not been identified and the development of insulin resistance represents a complex interaction among a poorly understood array of predisposing genetic factors and acquired environmental factors that modify insulin sensitivity. Among the latter, the most prominent are obesity (particularly intra-abdominal obesity), physical inactivity, and increasing age. It is also now well documented...

Relationship Between Obesity And Type 2 Diabetes Mellitus

Although ft adrenergic agonists have been under study in rodents for more than 20 years, only in the past several years has the uniqueness of the primate (human and non-human) receptor been identified. Currently, agents under study are specific for the human receptor and are being extensively tested in non-human primates whose receptor is very similar the human sequence(100). The receptor sequence in the rhesus monkey is shown in Figure 14.9. Studies of agonists in monkeys have been reviewed recently (101). Such agonists have been shown to be active at the non-human primate receptor (102), acutely producing lipolysis and metabolic rate elevation and increased UCP1 expression in brown adipose tissue. To date, however, none has been reported to produce a reduction in body weight. This may be due to an insufficient number of receptors on the adipose tissue of humans. Recent studies have shown an increase in the expression of the mitochondrial uncoupling proteins (UCP2 and 3), and...

Dormancy size and phylogeny

During the active portion of an insect's life cycle desiccation stress is probably frequent, but shortlived. In addition, the active stages (larvae and adults) have regular access both to free water and to water in their food. In contrast, during dormancy (diapause, quiescence, aestivation), dehydration is likely to be prolonged and access to water and energy resources extremely limited (Lighton and Duncan 1995 Danks 2000). At this time, there is likely to be strong selection both for low metabolic rate, to conserve energy resources, and for any mechanisms that might reduce water loss. Insects overwintering in temperate regions are also subject to desiccating conditions, and some show remarkable resistance to desiccation even when individuals are removed from their plant galls Effects of desiccation on eggs and even smaller first instar larvae were recently compared for two species of Lepidoptera, Grammia geneura (Arctiiidae) and M. sexta (Sphingidae) (Woods and Singer 2001), with an...

Nutritional Management

Nutritional management goals are listed in Table 18-3. Energy, protein, and micronutrient requirements for sustaining lean body mass and supporting normal growth and development in the AIDS setting are not well defined. Infectious diseases characteristically increase energy requirements, and HIV infection itself may increase basal metabolic rate.8 Since weight loss or gain is the ultimate measure of energy needs, calorie requirements should be calculated according to the general guidelines in Chapter 5 with allowance made for energy needs of opportunistic infections or malabsorption.9 Micronutrient deficiencies may be prevented by providing vitamin mineral supplements at doses equal to one to two times the Recommended Dietary Allowance.'1 Strategies for nutritional management of the symptomatic HIV-infected child are summarized in Table 18-4.

Metabolic Regulation of cADPR Accumulation

Despite extensive investigations, we have yet to determine the precise mechanism by which hypoxia regulates cADPR accumulation. It seems likely that a change in the metabolic state of pulmonary artery smooth muscle will mediate this effect via one or a group of primary metabolic sensor. In subsequent sections of this chapter, therefore, I will review the information currently available to us, in an effort to determine the likely identity of the metabolic sensor(s) and metabolic effector(s) involved.

Birds More Feathers and Better Flight

The bones of birds are modified for flight. They are hollow and have internal struts for strength. The sternum (breastbone) forms a large, vertical keel to which the flight muscles are attached. These muscles pull the wings downward during the main propulsive movement in flight. Flight is meta-bolically expensive. A flying bird consumes energy at a rate about 15-20 times faster than a running lizard of the same weight Because birds have such high metabolic rates, they generate large amounts of heat. They control the rate of heat loss using their feathers, which may be held close to the body or elevated to alter the amount of insulation they provide.

General Physical Health

Rates of comorbid physical illness in schizophrenic patients have been reported to occur primarily in the categories of non-insulin-dependent diabetes mellitus (NIDDM), cardiovascular disease, infectious diseases, respiratory disease, some forms of cancer, and a variety of other illnesses (Dixon et al. 1999). It has also been suggested that persons with schizophrenia may be subject to more severe forms of disorders (Jeste et al. 1996), which may be exacerbated by the side effects of antipsychotic medications (e.g., anticholinergic, cardiovascular, or metabolic effects) and by psychotic illness itself, with significant correlations found between positive symptoms and the number of medical conditions (Dixon et al. 1999 Jeste et al. 1996).

Does the Cellular Redox State Play a Role in the Regulation of cADPR Accumulation in Pulmonary Artery Smooth Muscle

We were drawn to investigate the possibility that cADPR may be a mediator of HPV for two reasons. As mentioned previously, cADPR had been proposed as an endogenous regulator of RyRs (29, 55), and we had obtained evidence of a role for smooth muscle SR Ca2+ release via RyRs in maintained HPV (23). An additional attraction, however, was the fact that cADPR is a P-NAD+ metabolite. This was because hypoxia had been shown to increase p-NADH levels in all 02-sensing cells studied to date (5, 11, 79, 92). When taken together, these findings suggested that cADPR synthesis itself may, in some way, be sensitive to changes in the metabolic state of pulmonary artery smooth muscle, and that it may thereby play a role in HPV.

Feeding Strategy of Jellyfish

Jellyfish are simple but specialized carnivores. Although jellyfish have a low metabolic rate, they have the ability to capture large prey. These two characteristics allow jellyfish to survive in environments where prey are scarce. Jellyfish are equipped with a specialized apparatus, the cnidoblast, for defense and feeding. Cnidoblasts are found by the hundreds or thousands on the tentacles and sometimes on the body surface. Within each cnidoblast is a coiled harpoonlike nematocyst that is discharged by the presence of potential prey. The nematocyst injects poison into the prey as spines on the nematocyst anchor it to the prey. The trapped, paralyzed prey is pulled back by the tentacles and stuffed into the gastro-vascular cavity to be digested. Jellyfish do not attack humans, but humans may receive stings if they encounter jellyfish. The effects of jellyfish poison on humans can range from a mild, itchy rash to death.

Concrete Applications Of Hypnotic Techniques

Since physical exercise to increase metabolism is of crucial importance for promoting weight loss, the patient will receive a suggestion to start with more and regular movement during a hypnosis exercise. After hypnosis induction the patient is asked to imagine that she is for instance riding a bicycle. While cycling, suggestions are given to become more and more relaxed, reaching a deeper state of trance and or relaxation. This exercise aims also to motivate the patient to start cycling (with a home-trainer) in the actual situation at home. And now that you have started pedalling, you can listen to my voice and concentrate on all the sensations in your body And while you are pedalling continuously, you can become more and more aware of the rhythmic movement of your muscles, especially your legs. Try to concentrate more and more on the rhythmic movement of your legs, Maybe you will notice how this movement, the pedalling, will become more and more automatic, how cycling becomes...

Box 171 The World Of Biochemistry

Many animals depend on fat stores for energy during hibernation, during migratory periods, and in other situations involving radical metabolic adjustments. One of the most pronounced adjustments of fat metabolism occurs in hibernating grizzly bears. These animals remain in a continuous state of dormancy for periods as long as seven months. Unlike most hibernating species, the bear maintains a body temperature of between 32 and 35 C, close to the normal (nonhiber-

Imaging The Cellsickness Stage Of Ad With Functional

It is important to maintain a precise definition of the function in functional imaging, so as not to misinterpret its meaning or utility. Over the 50 years that the field has evolved, since the seminal work by Kety and Schmidt 17 , functional brain imaging has come to imply a method that detects regional energy metabolism. Energy metabolism is best defined as the rate with which cells produce ATP, which in neurons obligate aerobes who do not store glucose requires the consumption of oxygen and glucose from the bloodstream. Visualizing ATP directly is challenging, but imaging techniques have been developed that can visualize correlates of oxygen and glucose consumption. With the use of radiolabeled glucose, positron emission tomography (PET) can quantify the regional rates of glucose uptake, which under certain assumptions corresponds to energy metabolism. In contrast, MRI-based techniques have typically relied on the second ingredient of ATP production, oxygen consumption, to...

Summary And Conclusions

Weight gain associated with tricyclic antidepress-ant and certain antipsychotic medications is problematic for many treated patients, and often a reason for non-compliance. Such weight gain is associated, at least in part, with reductions in resting metabolic rate and diet-induced thermogenesis. Changes in food preference towards calorically dense ('fattening') sweet-tasting foods do not appear to affect a majority of patients treated with tricyclic medications, but can occur. When such preference changes do occur, though, they are not associated with the development or maintenance of obesity. Another class of antidepressants, specific serotonin reuptake inhibitors (SSRIs), have been used in the past few years as effective antidepressants, but do not promote weight gain during treatment, although this is occasionally seen. The antipsychotic medications often promote weight gain, particularly the conventional medications, but also some of the novel antipsychotics seem to have weight...

The embryo must mobilize its reserves

The giant molecules of starch, lipids, and proteins must be digested by enzymes into monomers that can enter the cells of the embryo. The polymer starch yields glucose for energy metabolism and for the synthesis of cellulose and other cell wall constituents. The digestion of stored proteins provides the amino acids the embryo needs to synthesize its own proteins. The digestion of lipids releases glycerol and fatty acids, both of which can be metabolized for energy. Glycerol and fatty acids can also be converted to glucose, which permits fat-storing plants to make all the building blocks they need for growth.

Experimental Stroke Disease Phenotyping Using Mrimrs

Due to the vital role of energy metabolism for proper tissue function, noninvasive 31P MRS has been applied to monitor levels of HEP such as ATP and PCr, characterizing the metabolic state of tissue (Figure 8.2). Cerebral HEP synthesis not matching HEP consumption will ultimately lead to energy failure, to brain dysfunction, and ultimately to brain death. This is the case, e.g., for status epilepticus, during which energy consumption is dramatically increased. Prolonged seizures have been shown to compromise tissue levels of PCr and later of ATP with a concomitant increase of intracellular pH reflecting anaerobic glucose metabolism 7 . Brain ischemia has analogous metabolic consequences during global cerebral ischemia, PCr levels disappear within 2 min following cessation of blood flow, while ATP reservoirs are depleted within typically 4 min following cardiac arrest 9 . Intracellular pH values drop from a normal value of 7.2 to values around 6.5, depending on the resting blood...

Mechanisms Of Postcessation Weight Gain

The exact mechanisms underlying post-cessation weight gain still are not well understood. According to the principles of energy balance, smoking cessation must lead to either an increase in energy intake, and or a decrease in energy expenditure (viz., metabolic rate, physical activity) to promote weight gain (33). Metabolic Rate Studies examining the relationship between smoking and metabolic rate have been inconclusive. There is considerable indirect evidence that metabolic factors influence the weight-controlling properties of smoking. The fact that smokers are no more active than non-smokers and consume as much or more energy, yet weigh less, suggests that metabolism may play a role in the relationship between smoking and body weight (34). Several studies have documented acute metabolic increases due to smoking or nicotine administration (61-64). At least one study did not find any acute effect of smoking on metabolic rate (65) and in general, there appears to be tremendous...

Upregulation of gene expression

The ubiquitous expression of PPAR beta made the identification of its function elusive. However, it has recently been shown that a PPAR beta-specific ligand promotes lipid accumulation in human macrophages, which can be considered potentially pro-atherogenic (Vosper et al., 2001). In contrast, the high and almost selective expression of PPAR gamma in adipocytes shows that it is likely to play a major role in the differentiation of these cells (Tontonoz et al., 1994 Grimaldi, 2001 Kliewer et al., 2001 Ferre, 2004). But there is a concern about its role in energy metabolism in these cells (Walczak and Tontonoz, 2002). Some genes (for example, those coding for the glucose transporter GLUT4, the acyl CoA synthase or the phospho-enol-pyruvate-CK) are involved in the activation and esterification of fatty acids and display specific DNA elements able to bind PPAR. However, simply because FA are potential ligands of PPARs does not necessarily imply that transcriptional effects of FA are...

Identification Of Transmembrane Proteins Using Variants Of The Selforganizing Feature Map Algorithm

Membrane proteins account for roughly one-third of all proteins and play a crucial role in processes such as cell-to-cell signaling, transport of ions across membranes, and energy metabolism 4,5,34 and are a prime target for therapeutic drugs 5,13,14,32 . One important subfamily of membrane proteins are the transmembrane proteins, of which there are two main types

Pentose Phosphate Pathway PPP

The importance of having adequate supplies of N ADPH for the regeneration of these various enzymes cannot be over emphasized. In normal situations this cofactor can be adequately provided by the reductive pentose phosphate pathway. Monitoring the activity of the pentose phosphate pathway has been proposed as a unique way to study the metabolic response to oxidative stress, since the glutathione peroxidase activity is coupled via glutathione reductase to the enzyme glucose-6-phosphate dehydrogenase (Ben Yoseph et al., 1994).

Introduction and background

This book explores the biological, cultural, and biocultural processes and environmental stressors through which human senescence, life span, and life history have evolved. The emphasis is on evolutionary, biocultural, and ecological aspects of human aging and senescence, rather than animal and cellular senescence, which are examined extensively elsewhere (Finch 1990 Rose 1991). Human life history evolved as part of the adaptive repertoire of a unique, bipedal, large-brained, large-bodied, gregarious, and polygamous hominid. These specific aspects of hominid evolutionary history necessarily determine to some degree current variation in our species' life history and our individual life spans - minimal maximum metabolic rates, patterns of reproduction, maximum rates of growth, development and maturation, encephalization, and the DNA content of our cells. Although many such variables show high correlations with observed average and maximum life spans across species, they may provide...

Thyroid dysfunction causes goiter

Goiter occurs when the production of thyroglobulin is far above normal and the follicles become greatly enlarged. Hy-perthyroid goiter results when the negative feedback mechanism fails to turn off the follicle cells even though blood levels of thyroxine are high. The most common cause of hyperthyroidism is an autoimmune disease in which an antibody to the TSH receptor is produced. This antibody can bind to the TSH receptor on the follicle cells, causing them to produce and release thyroxine. Even though blood levels of TSH may be quite low because of the negative feedback from high levels of thyroxine, the thyroid remains maximally stimulated, and it grows bigger. Hyperthyroid patients have high metabolic rates, are jumpy and nervous, usually feel hot, and may have a buildup of fat behind the eyeballs, causing their eyes to bulge.

Core Temperature Is Close to Central Blood Temperature

Core temperature varies slightly from one site to another depending on such local factors as metabolic rate, blood supply, and the temperatures of neighboring tissues. However, temperatures at different places in the core are all close to the temperature of the central blood and tend to

Heat Is a Byproduct of Energy Requiring Metabolic Processes

Metabolic Rate and Sites of Heat Production at Rest. Among subjects of different body size, metabolic rate at rest varies approximately in proportion to body surface area. In a resting and fasting young adult man it is about 45 W m2 (81 W or 70 kcal hr for 1.8 m2 body surface area), corresponding to an O2 consumption of about 240 mL min. About 70 of energy production at rest occurs in the body core trunk viscera and the brain even though they comprise only about 36 of the body mass (Table 29.2). As a by-product of their metabolic processes, these organs produce most of the heat needed to maintain heat balance at comfortable environmental temperatures,- only in the cold must such by-product heat be supplemented by heat produced expressly for thermoregulation. Factors other than body size that affect metabolism at rest include age and sex (Fig. 29.5), and hormones and digestion. The ratio of metabolic rate to surface area is highest in infancy and declines with age, most rapidly in...

Postprandial lipaemia

Most studies with n-3 PUFA-rich fats showed a reduced postprandial lipaemia when ingested in the daily diet or as a single meal (Weintraub et al., 1988 Tinker et al., 1999) compared with other fat sources. Comparisons of the effects of n-6 PUFA-rich oils with olive oil n-9 monounsaturated fatty acids or MUFA showed lower (de Bruin et al., 1993) or comparable (Lichtenstein et al., 1993 Tholstrup et al., 2001) magnitudes of postprandial lipaemia. There is physiological evidence that different MUFA-rich oils can lead to similar plasma lipid and lipoprotein profiles in fasting healthy subjects, but can produce different functional and postprandial responses. Recently Abia et al. (2001) showed that virgin olive oil as compared to a high oleic sunflower oil intake reduced the postprandial TAG lipoprotein response. This suggests that factors other than the oleic acid content may be responsible for the different metabolic effects. Chylomicrons formed after olive oil feeding appear to enter...

Thermoregulatory Control

In discussions of control systems, the words regulation and regulate have meanings distinct from those of the word control (see Chapter 1). The variable that a control system acts to maintain within narrow limits (e.g., temperature) is called the regulated variable, and the quantities it controls to accomplish this (e.g., sweating rate, skin blood flow, metabolic rate, and thermoregulatory behavior) are called controlled variables.

The mixedfunction oxygenase system

Proteins) before phase II metabolism can detoxify them. This process is called bioactivation. A well-known example is the activation of certain polycyclic aromatic hydrocarbons (a group of chemicals occurring in crude oil, diesel exhaust, and tar) to very reactive intermediates that are highly mutagenic and carcinogenic. The production of such very reactive compounds with obvious negative metabolic effects can be seen as an unavoidable evolutionary trade-off against the capacity to metabolize toxins and xenobiotics. In addition, with some substrates cytochrome P450 produces large amounts of ROS as a by-product. These two negative side effects of biotransformation may explain why upregulated monooxygenase is often accompanied by upregulation of antioxidant enzymes and heat-shock proteins. Fig. 6.8 provides an overview of the different possibilities for the fate of a foreign compound that undergoes biotransformation.

The Blood Lipid Profile Is Influenced by Exercise Training

Because exercise acutely and chronically enhances fat metabolism and cellular metabolic capacities for (3-oxidation of free fatty acids, it is not surprising that regular activity increases both muscle and adipose tissue lipoprotein lipase activity. Changes in lipoprotein li-pase activity, in concert with increased lecithin-cholesterol acyltransferase activity and apo A-I synthesis, enhance the levels of circulating HDLs.

How cancer cells differ from normal cells

Malignant tumors, or cancers, are aggregates of cells, all descended from an initial aberrant founder cell. In other words, the malignant cells are all members of a single clone. This is true even in advanced cancers having multiple tumors at many sites in the body. Cancer cells typically differ from their normal neighbors by a host of phenotypic characters, such as rapid division rate, ability to invade new cellular territories, high metabolic rate, and abnormal shape. For example, when cells from normal epithelial cell sheets are placed in cell culture, they can grow only when anchored to the culture dish itself. In addition, normal epithelial cells in culture divide only until they form a continuous monolayer (Figure 17-14a). At that point, they somehow recognize that they have formed a single epithelial sheet and stop dividing. In contrast, malignant cells derived from epithelial tissue continue to proliferate, piling up on one another (Figure 17-14b).

Clinical Focus Box 311

Growth hormone is a 191-amino acid protein hormone that is synthesized and secreted by somatotrophs of the anterior lobe of the pituitary gland. As described in Chapter 32, the hormone plays a role in regulating bone growth and energy metabolism in skeletal muscle and adipose tissue. A deficiency in growth hormone production during adolescence results in dwarfism and overproduction results in gigantism. Measurements of circulating growth hormone levels are, therefore, desirable in children whose growth rate is not appropriate for their age.

Regression And Depression

The metabolic rate rises significantly with burns, and attains a maximum of twice normal when the extent of the burn reaches 60 of body surface. Meeting caloric requirements is imperative for good wound healing, and recent studies indicate that enteral feeding may protect against endotoxemia and is preferable to intravenous feeding. Burned patients are often aware of the odor of their secretions and feel queazy or lacking in appetite. Hypnosis is widely used to control the nausea associated with chemotherapy, and Crasilneck (Crasilneck et al., 1955) has reported a depleted burn patient who increased his oral intake to 8000 Kcal per day with hypnotic suggestions to eat everything on his plate.

Clinical Focus Box 321

The insulin-opposing actions of GH can produce serious metabolic disturbances in individuals who secrete excessive amounts of GH (people with acromegaly) or are given large amounts of GH for an extended time. They may develop insulin resistance and an elevated insulin level in the blood. They may also have hyperglycemia caused by the underutilization and overproduction of glucose. These disturbances are much like those in individuals with non-insulin-dependent (type 2) diabetes mellitus. For this reason, this metabolic response to excess GH is called its diabetogenic action.

Other Dietary Treatment Programmes

Dietary treatment of obesity can vary between total starvation to diets which are only slightly hy-pocaloric. The most extreme form of diet is total starvation which means that no energy is given, whereas losses of water, electrolytes, vitamins and trace elements are compensated. Starvation obviously results in fast initial weight loss but requires medical supervision. Lethal complications have been described, probably because of cardiac arrhythmias (25). Starvation has the disadvantage of leading to considerable loss of lean body mass. Since most of the combustion takes place in such tissues, an increased breakdown of muscle in particular will result in a disproportionate reduction of the basic metabolic rate.

Pharmacologic MRI Compared with PET and Autoradiography How Well Do Hemodynamic Changes Reflect Receptor Distributions

The ability of both PET and autoradiography to measure direct binding of drugs to neuroreceptors would, at first glance, render the possibility of measuring specific receptor parameters based upon simple hemodynamic changes seem rather remote. At best, one might hope to verify the assumption that the hemodynamic changes observed after administration of a particular drug correlate with the activation of the receptor systems targeted by the drug. In this manner one would hope that there is a pharmacologically induced metabolic coupling entirely analogous to the metabolic coupling usually assumed in standard fMRI studies. Such correlations can be established empirically using techniques capable of measuring receptor binding, receptor distribution, and the attendant metabolic circuitry. These parameters in turn can be correlated with electrophysiologic data and companion metabolic studies. Such correlations might entail measuring BOLD signal changes and correlating these with changes in...

Longterm Results Of Dieting

During recent years it has become obvious that weight loss and weight maintenance after such weight loss represent two different components of the treatment strategy. Numerous programmes have shown considerable weight loss whereas weight maintenance after initial weight loss is rare. Thus the dietary composition during the initial weight loss may be of less importance during a phase when the weight loss is more driven by the energy deficiency than by the dietary composition in itself. As long as adequate protein supplies are available, preventing unnecessary breakdown of lean body mass with an ensuing reduction in basic metabolic rate, the composition of the diet during this phase may not be of major importance. However, when the weight-losing phase is over, generally after 6 months, the composition of the diet with regard to macronutrients may be crucial (51).

Thyroid Hormones Stimulate Intermediary Metabolism

In addition to their ability to regulate the rate of basal energy metabolism, thyroid hormones influence the rate at which most of the pathways of intermediary metabolism operate in their target cells. When thyroid hormones are deficient, pathways of carbohydrate, lipid, and protein metabolism are slowed, and their responsiveness to other regulatory factors, such as other hormones, is decreased. However, these same metabolic pathways run at an abnormally high rate when thyroid hormones are present in excess. Thyroid hormones, therefore, can be viewed as amplifiers of cellular metabolic activity. The amplifying effect of thyroid hormones on intermediary metabolism is mediated through the activation of genes encoding enzymes involved in these metabolic pathways.

Regulation of heat loss

Where C is convective thermal conductance, RHL is radiative heat loss and EHL is evaporative heat loss (Harrison and Fewell 2002). Radiative heat gain is negligible in indoor respirometry experiments (Roberts and Harrison 1999) but can be substantial in the field (Cooper et al. 1985). Convective cooling from a flying insect depends on air speed and the difference between body and air temperatures, so tends to decrease at higher Ta when the temperature excess is less. Convective heat loss is dominant in small insects and most insects fly with Tth close to Ta. Increases in wingbeat frequency with Ta have been measured in small stingless bees (Trigona jaty, 2.5 mg) and in flies (Unwin and Corbet 1984), and this will have a net cooling effect because surface effects predominate in these small insects. Metabolic rate is independent of flight speed in free-flying bumblebees (Ellington et al. 1990), and increasing flight speed has been suggested as a mechanism of increasing forced convection...

And Caloric Requirements

The total rate of body metabolism, or the metabolic rate, can be measured by either the amount of heat generated by the body or by the amount of oxygen consumed by the body per minute. This rate is influenced by a variety of factors. For example, the metabolic rate is increased by physical activity and by eating. The increased rate of metabolism that accompanies the assimilation of food can last more than 6 hours after a meal. Body temperature is also an important factor in determining metabolic rate. The reasons for this are twofold (1) temperature itself influences the rate of chemical reactions and (2) the hypothalamus contains temperature control centers, as well as temperature-sensitive cells that act as sensors for changes in body temperature. In response to deviations from a set point for body temperature (chapter 1), the control areas of the hypothalamus can direct physiological responses that help to correct the deviations and maintain a constant body temperature. Changes in...

Evolution Metabolism and Ecology

Biologists interested in metabolism and the factors that cause metabolic rate to change have examined the relationship between metabolic rate and other physiological functions. Specifically, oxygen supply, carbon dioxide removal, and glucose supply have been examined because all three are directly involved in aerobic metabolism. Imposing a limitation on external oxygen supply has therefore been used as an experimental tool to probe the limits and capabilities of cellular metabolism. See also Circulatory systems of invertebrates Circulatory systems of vertebrates Gas exchange Heart Lungs, gills, and tracheas Metabolic Rates Mountains Respiration Respiration in birds.

Control and Regulation of Fuel Metabolism

Most animals do not eat continuously. When they do eat, food is present in the gut, and nutrients are being absorbed, for some period of time after a meal, called the absorptive period. Once the stomach and small intestine are empty, nutrients are no longer being absorbed. During this postabsorptive period, the processes of energy metabolism and biosynthesis must run on internal reserves. Nutrient traffic must be controlled so that reserves accumulate during the absorptive period and are used appropriately during the postabsorptive period.

Spatial variation and its implications

In the following chapters, we drew attention to coherent, though sometimes weak, large-scale spatial variation in traits, including metabolic rate (Chapter 3), water loss rate (Chapter 4) and thermal tolerances (Chapter 5). In our view, one of the most biologically significant results emerging from the large-scale perspective is that, at several spatial scales, there appears to be a general decoupling of upper and lower lethal temperature limits.

Box 273 The World Of Biochemistry

Certain peptides could stabilize large RNA molecules. For example, many ribosomal proteins in modern eukaryotic cells have long extensions, lacking secondary structure, that snake into the rRNAs and help stabilize them (Fig. 1). Ribozyme-catalyzed synthesis of peptides could thus initially have evolved as part of a general solution to the structural maintenance of large RNA molecules. The synthesis of peptides may have helped stabilize large ribozymes, but this advance also marked the beginning of the end for the RNA world. Once peptide synthesis was possible, the greater catalytic potential of proteins would have set in motion an irreversible transition to a protein-dominated metabolic system.

Interactions internal and external

While separating thermal tolerances and regulation, water balance, metabolism, and growth and differentiation, is convenient, it in no way reflects reality. Insects must solve several environmental problems simultaneously (Park 1962 Scriber 2002). At any given time, they have to obtain sufficient resources for development and or reproduction, avoid succumbing before they have reproduced, and cope with much environmental variation. For example, during dormancy (in an insect from seasonally dry subtropical South Africa) dehydration is likely to be prolonged and access to water and energy resources extremely limited. Therefore, there is likely to be strong selection for low metabolic rate to conserve energy resources, and for any mechanisms that might reduce water loss. Many arthropods also spend this time below ground, where conditions are at least mildly hypoxic and hypercapnic, so there is also likely to be selection for improved gas exchange capabilities (Chown 2002). In consequence,...

Internal interactions

Cross-resistance (or cross-tolerance), where exposure to one kind of stress enhances resistance to others, is well known in insect physiological ecology (Hoffmann and Parsons 1991 Hoffmann et al. 2003b). In Section 5.4, the responses of upper or lower thermal tolerances to stress at the other end of the temperature spectrum were discussed in detail. While these effects are generally small and are probably the result of shared mechanisms, cross-resistance goes well beyond high and low-temperature interactions. It has been demonstrated in a wide range of laboratory selection experiments involving thermal tolerances, desiccation resistance, metabolic rate, and tolerance to ethanol in Drosophila. Stress protein expression is certainly characteristic of the response to many of these stressors (Feder and Hofmann 1999), and may well underlie the cross-tolerance here too. However, a reduction in metabolic rate is also thought to be a general response to stressful conditions, though this...

And Mitochondrial Leukoencephalopathies

Pyruvate Dehydrogenase Deficiency Mri

Leigh syndrome is caused by a number of inborn errors of energy metabolism. Frequent causes are pyruvate dehydrogenase complex deficiency, complex I (NADH coenzyme Q reductase, NADH ubi- Leigh syndrome is caused by a number of inborn errors of energy metabolism. Frequent causes are pyru-vate dehydrogenase complex deficiency, complex I All defects underlying Leigh syndrome affect energy metabolism. There is a striking clinical and morphological similarity between Leigh syndrome and thiamine deficiency (beriberi). Thiamine is part of the pyruvate dehydrogenase, ketoglutarate dehydro-genase, and branched-chain keto acid dehydrogenase complexes, and deficiency leads to a disturbance in oxidation of pyruvate and consequently to energy failure. The only histopathological differences between thiamine deficiency and Leigh syndrome are that in thiamine deficiency the mammillary bodies are mostly involved and the substantia nigra is not, whereas in Leigh syndrome it is the substantia nigra that...

Satiety Signals And The Satiety Cascade

Satiety Cascade

Initially the brain is informed about the amount of food ingested and its nutrient content via sensory input. The gastrointestinal tract is equipped with specialized chemo- and mechano-receptors that monitor physiological activity and pass information to the brain mainly via the vagus nerve (4). This afferent information constitutes one class of 'satiety signals' and forms part of the pre-absorptive control of appetite. It is usual to identify a post-absorptive phase that arises when nutrients have undergone digestion and have crossed the intestinal wall to enter the circulation. These products, which accurately reflect the food consumed, may be metabolized in the peripheral tissues or organs or may enter the brain directly via the circulation. In either case, these products constitute a further class of metabolic satiety signals. Additionally, products of digestion and agents responsible for their metabolism may reach the brain and bind to specific chemoreceptors, influence...

Functions of the Adrenal Medulla

The cells of the adrenal medulla secrete epinephrine and nor-epinephrine in an approximate ratio of 4 to 1, respectively. The effects of these catecholamine hormones are similar to those caused by stimulation of the sympathetic nervous system, except that the hormonal effect lasts about ten times longer. The hormones from the adrenal medulla increase the cardiac output and heart rate, dilate coronary blood vessels, increase mental alertness, increase the respiratory rate, and elevate the metabolic rate.

Responses to osmotic stress

Trehalulose

Tolerance has evolved at least five times independently in mosquitoes, but only two physiological strategies are involved (Bradley 1994). Some species of Aedes, Opifex, and Anopheles are osmo-regulators, and the rectal salt gland of Aedes secretes NaCl-rich hyperosmotic fluid and has been studied in detail. Other genera (Culex, Culiseta) include osmoconformers, which accumulate organic osmo-lytes in their haemolymph above the isosmotic point this reduces the need for transporting ions and is a cheaper solution to the problem of inhabiting saline environments. Regulation of high haemolymph concentrations of trehalose and proline has been examined in detail in euryhaline Culex tarsalis, in comparison with freshwater C. quinquefasciatus (Patrick and Bradley 2000a,b). Trehalose and proline are used in energy metabolism, have a low molecular mass, and do not disrupt enzyme action when accumulated in high concentrations. Recent comparison of Na + and Cl_ uptake mechanisms in C....

Cyclic Adenosine Diphosphate Ribose cAdpr Sr Ca2 Release and Maintained Hypoxic Pulmonary Vasoconstriction in Isolated

Sensitize Ca2+-induced Ca2+ release via RyRs in the SR and to induce SR Ca2+ release by RyR activation (22). Furthermore, we were struck by the fact that cADPR was a P-NAD+ metabolite, since hypoxia had been shown to increase p-NADH levels in all 02-sensing cells studied to date (5, 59, 67). This offered the possibility that cADPR synthesis itself may, in some way, be sensitive to changes in the metabolic state of pulmonary artery smooth muscle.

Inborn errors of metabolism

Urine Oligosaccharides Gamt

Organic acidemias, also known as organic acidurias, are a group of disorders characterized by increased excretion of organic acids in urine. They result primarily from deficiencies of specific enzymes in the breakdown pathways of amino acids or from enzyme deficiencies in -oxidation of fatty acids or carbohydrate metabolism. Organic acidemias can be classified into five categories including branched-chain organic acidemias, multiple carboxylase deficiency, including holocarboxylase synthetase deficiency and biotinidase deficiency, glutaric aciduria type I and related organic acidemias, fatty acid oxidation defects, and disorders of energy metabolism. For example, the diagnosis of methylmalonic aciduria (MMA) is made by measurement of organic acids in the urine using GC-MS. In MMAlarge amounts of methylmalonic acid, as well as methylcitrate, propionic acid, and 3-OH propionic acid, are present 14,15 .

Chemoreceptors Detect Changes in Pco2 pH and Po2

The increased firing of both peripheral and central chemoreceptors (via the NTS and RVL) leads to profound peripheral vasoconstriction. Arterial pressure is significantly elevated. If respiratory movements are voluntarily stopped, the vasoconstriction is more intense and a striking bradycardia and decreased cardiac output occur. This response pattern is typical of the diving response (discussed later). As in the case of the baroreceptor reflex, the coronary and cerebral circulations are not subject to the sympathetic vasoconstrictor effects and instead exhibit vasodila-tion, as a result of the combination of the direct effect of the abnormal blood gases and local metabolic effects.

Review Activities

The basal metabolic rate is determined primarily by b. The metabolic rate will be increased over basal conditions. Compare the metabolic effects of 3. Describe how thyroxine affects cell respiration. Why does a person who is hypothyroid have a tendency to gain weight and less tolerance for cold Compare and contrast the metabolic effects of thyroxine and growth hormone.

Bees food quality and body temperature

Increasing Body Temperature Bees

Not surprisingly, the metabolic rate of honeybees likewise varies with the reward rate at the food source and the motivational state of the bees. Direct effects of nectar load on metabolic rate (Wolf et al. 1989) can be eliminated by training bees to collect food in a respirometer so that they need not transport it (Moffat and Nunez 1997). The metabolic rate of free-flying bees collecting food in a much larger respirometer is also inversely proportional to Ta at constant sucrose flow rate (Moffatt 2001), supporting previous studies showing variation of heat production during flight (Roberts and Harrison 1999).

Ctenophores Complete Guts and Tentacles

Jellyfish Life Cycle

Were the next lineage to diverge from the lineage leading to all other animals. Cteno-phores, also known as comb jellies, have body plans that are superficially similar to those of cnidarians. Both have two cell layers separated by a thick, gelatinous mesoglea, and both have radial symmetry and feeding tentacles. Like cnidarians, ctenophores have low metabolic rates because they are

Thermoregulation in Endotherms

As we saw in Figure 41.7, endotherms respond to changes in environmental temperature by changing their metabolic rate. Within a narrow range of environmental temperatures, called the thermoneutral zone, the metabolic rate of endotherms is low and independent of temperature. The metabolic rate of a resting animal at a temperature within the thermoneutral zone is called the basal metabolic rate. It is usually measured in animals that are quiet but awake and that are not using energy for digestion, reproduction, or growth. A resting animal consumes energy at the basal metabolic rate just to carry out all of its minimal body functions. The basal metabolic rate of an endotherm is about six times greater than the metabolic rate of an ectotherm of the same size and at the same body temperature (see Figure 41.7b). A gram of mouse tissue consumes energy at a much higher rate than does a gram of lizard tissue when both tissues are at 37 C. This difference results from basic changes in cell...

Cerebral Palsy And Developmental Disabilities

Caloric requirements may be assessed in several ways (1) calories per centimeter of body height length (Table 22-2) (2) catch-up growth equations using height age instead of weight age or (3) standard equation using Basal Energy Expenditure (BEE) x activity and injury factors.1 It is important to note, however, that these methods are merely guidelines and that individual calorie requirements should be assessed based on changes in weight over time and or measurement of basal metabolic rate, if possible. Therefore, regular weight monitoring is an essential component in managing children with DD, Caloric requirements may be as low as 5 kcal cm of height in children with severe central nervous system impairment.r>

Haemolymph composition

Orders, inorganic ions tend to be replaced as the main haemolymph osmolytes by organic molecules. From being the dominant haemolymph cation, Na + is dramatically reduced in many phytophagous insects, especially in the larval stages. This may reflect the fact that sodium is a limiting element in plant tissues and varies geographically and with plant species, tissue and age (Denton 1982). A blood Na + concentration of only 0.2 mM measured in the aphid Myzus persicae was claimed by Downing (1980) to be the lowest, by an order of magnitude, for any animal. Important organic osmolytes are amino acids, trehalose, and organic acids (Mullins 1985). Haemolymph sugar concentrations can be extremely high, as in the pea aphid Acyrthosiphon pisum, which has haemolymph with a high osmolality and a trehalose concentration of 255 mM (Rhodes et al. 1997). Analysis of the haemolymph of larval Onymacris rugatipennis (Coleoptera, Tene-brionidae) showed approximately equal osmotic contributions from...

Regulatory Functions of Adipose Tissue

It is difficult for a person to lose (or gain) weight, many scientists believe, because the body has negative feedback loops that act to defend a particular body weight, or more accurately, the amount of adipose tissue. This regulatory system has been called an adipostat. When a person eats more than is needed to maintain the set point of adipose tissue, the person's metabolic rate increases and hunger decreases, as previously described. Homeostasis of body weight implies negative feedback loops. Hunger and metabolism (acting through food and hormones) affect adi

Regulation of heat gain

Do insects vary their flight performance for thermoregulatory as well as aerodynamic purposes Metabolic rate in flight has been shown to be independent of Ta in various large endothermic insects for example, sphinx moths Hyles lineata (Casey 1976), bumblebees Bombus spp. (Heinrich 1975), carpenter bees Xylocopa capitata (Nicolson and Louw 1982). If VO2 in flight is unchanged with Ta, heat production must be constant and regulation of Tth can only be achieved by heat loss. This generally accepted picture (Heinrich 1993) changed when Harrison et al. (1996) demonstrated that free-flying honeybees subjected to a rise in Ta from 20 to 40 C decrease their wingbeat frequency and MHP (calculated from CO2 production). Variation in MHP accounts for most of the thermoregulation of flying honeybees between Ta of 21 and 33 C, whereas evaporative heat loss is also important between 33 and 45 C (see the negative water balance at high Ta in Fig. 4.5) (Roberts and Harrison 1999).

Intrinsic Regulation of Blood Flow

Local vasodilation within an organ can occur as a result of the chemical environment created by the organ's metabolism. The localized chemical conditions that promote vasodilation include (1) decreased oxygen concentrations that result from increased metabolic rate (2) increased carbon dioxide concentrations (3) decreased tissue pH (due to CO2, lactic acid, and other metabolic products) and (4) the release of adenosine or K+ from the tissue cells. Through these chemical changes, the organ signals its blood vessels of its need for increased oxygen delivery.

Introduction History of Metabonomics

Metabonomic analysis involves the quantitation of the dynamic multivariate metabolic response of an organism to a pathological event or genetic modification 1 . The concept of metabonomics has evolved over two decades of 1H NMR spectroscopic analysis of the multicomponent metabolic composition of biofluids, cells, and tissues under different physiological and

Hypocretin Actions In The Adrenal Gland

Mineralocorticoid Actions The Brain

The transgenic model that perhaps best mirrors human narcolepsy is the ataxin-3 expressing mouse62 and now rat.30 These animals express normal levels of the hypocretins until early adulthood, when expression of the truncated Machado-Joseph disease gene (driven by the orexin promotor) product causes lethality in neurons expressing the protein. The mice display as adults the behavioral phenotype most similar to human narcolepsy and in addition develop late-onset obesity, and what appears to be insulin resistance. Transgenic mice ate less food, but consistently gained more weight than wild type littermates. The decreased food intake may have been due to a loss of the orexigenic action of the hypocretins. These transgenic animals did display less spontaneous motor activity than controls during the dark phase, when the cataplexic attacks were most prevalent, and therefore a decreased metabolic rate may have contributed to the weight gain, although his was not directly assessed. This is...

The Aminergic Systems

Among the aminergic systems in the brain, histamine has received the least attention although it is an equally important regulator of many homeostatic body functions,21 including control of behavioral state (maintenance of wakefulness),69-71 appetite and energy metabolism, neuroendocrine regulation, nociception, and learning or memory.21 Indeed, several lines of evidence indicate an exceptionally close anatomical and functional relationship between histamine and hypocretin neurons, who exhibit mutual connectivity, cooperativity and associativity also with other neuroendocrine systems.72

The Rate of Diffusion Depends on Permeability and Concentration Differences

The number of perfused capillaries and blood and tissue concentrations of solutes are constantly changing, and chronic changes occur as well. Therefore, the diffusion distance and surface area for exchange can be influenced by physiological events. The same is true for concentrations in the tissue and blood. In this context, microvascular exchange is dynamically altered by many physiological events. For example, about half of the capillaries of the intestinal villus are perfused when the bowel lumen is empty. During absorption of foodstuff, all of the capillaries are perfused as arterioles dilate to provide a higher blood flow to support the increased metabolic rate of villus epithelial cells. In many cases, the above scenario may not be true. For example, as blood passes through the tissues, the tissues extract approximately one fourth to one third of the oxygen contained in arterial blood before it reaches the capillaries. The oxygen diffuses directly through the walls of the...

Energy Requirements of Skeletal Muscles

Skeletal muscles generate ATP through aerobic and anaerobic respiration and through the use of phosphate groups donated by creatine phosphate.The aerobic and anaerobic abilities of skeletal muscle fibers differ according to muscle fiber type, which are described according to their speed of contraction, color,and major mode of energy metabolism.

The Balance Between Heat Production And Heat Loss

Where M is metabolic rate,- E is rate of heat loss by evaporation,- R and C are rates of heat loss by radiation and convection, respectively,- K is the rate of heat loss by conduction,- W is rate of energy loss as mechanical work,- and S is rate of heat storage in the body, manifested as changes in tissue temperatures.

Exchange of Molecules Across the Placenta

The placenta is not merely a passive conduit for exchange between maternal and fetal blood, however. It has a very high metabolic rate, utilizing about a third of all the oxygen and glucose supplied by the maternal blood. The rate of protein synthesis is, in fact, higher in the placenta than in the liver. Like the liver, the placenta produces a great variety of enzymes capable of converting hormones and exogenous drugs into less active molecules. In this way potentially dangerous molecules in the maternal blood are often prevented from harming the fetus.

Cardiovascular control in diving mammals conserves oxygen

While diving, the seal accumulates lactic acid in its muscles, which constitutes an oxygen debt to be paid back through elevated metabolism after the dive ends. But the total metabolic debt is much less than the metabolism that would have occurred over the same period of time had the seal not dived. The diving reflex causes the seal to be hy-pometabolic (to have a metabolic rate below its basal rate) during the dive. Hypometabolism, increased oxygen stores, and a high capacity for anaerobic metabolism make it possible for the seal to perform its amazing diving feats.

Ectotherms and endotherms respond differently to changes in environmental temperature

A small lizard can serve as an example of an ectotherm. We can compare it with a mouse, which is an endotherm of the same body size. We can put each animal in a closed chamber and measure its body temperature and metabolic rate as we change the temperature of the chamber from 0 C to 35 C. The results obtained from the two species differ. The body temperature of the lizard equilibrates with that of the chamber, whereas the body temperature of the mouse remains at 37 C (Figure 41.7a). The metabolic rate of the lizard decreases as the temperature decreases (Figure 41.7b). In contrast, the mouse's metabolic rate increases as chamber temperature falls below about 27 C (notice that you must read the graph right to left to see this). Based on these observations, we might conclude that the lizard cannot regulate its body tem

Anaerobic pathways and environmental hypoxia

Most terrestrial insects are metabolic regulators. With declining pO2, oxygen consumption remains constant until a critical oxygen tension of about 5-10 kPa (generally lower in adults) (Loudon 1988). Thereafter, metabolic rate declines precipitously, and ATP levels are generally not defended while concentrations of ADP, AMP, and IMP increase (Hoback and Stanley 2001 Kolsch et al. 2002). At least some energy is made available via anaerobic metabolism with lactate and alanine forming the major end-products. In species that are regularly exposed to anoxia, such as the tiger beetle Cicindela togata, metabolism is rapidly downregulated and ATP levels are defended for at least 24 h. Thereafter anaerobic metabolism is responsible for energy provision (Hoback et al. 2000). Survival of long-term anoxia in the Arctic carabid beetle Pelophila borealis (Carabidae) is associated with metabolic downregulation and with provision of small amounts of energy via a lactate pathway (Conradi-Larson and...

If An Ob Ob Mouse Both Copies Of The Ob Gene Are Defective And A Normal Ob Ob Mouse Two Good Copies Of The Ob Gene Were

Parabiotic Mice

Thyroid hormones are intimately involved in regulating the basal metabolic rate. Liver tissue of animals given excess thy-roxine shows an increased rate of O2 consumption and increased heat output (thermogenesis), but the ATP concentration in the tissue is normal. Different explanations have been offered for the thermogenic effect of thyroxine. One is that excess thryroxine causes uncoupling of oxidative phos-phorylation in mitochondria. How could such an effect account for the observations Another explanation suggests that the thermogenesis is due to an increased rate of ATP utilization by the thyroxine-stimulated tissue. Is this a reasonable explanation Why

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