Relaxation Techniques

Relaxation Audio Sounds Log Cabin Fire

Relaxation Audio Sounds Log Cabin Fire

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Brain Evolution System

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Brain Evolution System Overview

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Irreversible Magnetic Relaxation

The magnetic moment of a ferromagnetic system magnetized in an external field and then left on its own often changes with time. This is one of the manifestations of the so-called ''irreversible magnetic relaxation phenomena'', which inevitably occur at finite temperatures in any magnetic system which is not in a thermal equilibrium state. A typical experiment to observe irreversible magnetic relaxation is as follows a system is magnetized in an external field so that it acquires some total magnetic moment in the direction of this field. The magnitude and (or) the direction of the applied field is then suddenly changed and the time dependence of the system magnetic moment is measured. For a wide class of magnetic systems (magnetic powders, some alloys, thin films, etc.) such measurements provide a nontrivial result magnetization relaxation is not exponential (mz exp( t tc), which one would expect for the thermal relaxation of a system over an energy barrier) but rather can be described...

Brain Tissue Relaxation Times Diffusion Properties and Cerebrovascular Flow Abnormalities

Alternative structural MRI approaches are based on the quantitative assessment of MRI parameters determining image contrast. For instance, the occurrence of microstructural changes in brain parenchyma due to plaque and tangle formation should translate into locally altered MRI relaxation times. High-field MRI has been used to investigate brain regional changes of MR relaxation times in two different murine AD models 76 . The transverse relaxation time T2 was significantly reduced in various brain regions (hippocampus, cingulate, and retrosplenial cortex) of PSAPP mice 24 as compared to nontransgenic animals. No significant differences were observed between T2-values measured in PS mice 23 , which do not display deposition of solid A 3-containing plaques, and control animals. These results indicate that T2 might constitute a sensitive marker of parenchymal abnormalities due to massive deposition of insoluble A 3. No significant changes have been found in the longitudinal relaxation...

Changes in Relaxation Times

A third fundamental challenge for ultrahigh field MRI arises from the fact that relaxation times change substantially compared to lower field strengths, thus significantly altering image appearance. Bottomley extrapolated data obtained at lower field strengths, and predicted increasing tissue T1 relaxation times with increasing field strength, whereas T2 relaxation times were predicted to remain approximately constant (Bottomley et al., 1984). Because of susceptibility effects, T2* relaxation times are expected to become significantly shorter at ultrahigh field MRI. Since all Table 3.1. Relaxation time measurements at 8 T.

Relaxation Is Just A Breath Away

When a patient is obviously anxious about being in the dental treatment room and wants a quick procedure for experiencing a relaxing hypnotic state, the 5-minute relaxation exercise, developed by the author in 1982, is offered. The patient does this hypnotic exercise before the dental procedure is initiated. There is no need for the doctor to be present while the patient is experiencing the calming affects. Copies of this tape can be given to patients to practice at home, or the tape can be listened to as the first part of the dental visit.

Thermal Relaxation Effects in Magnetic Nanoparticles

Heating of magnetic particles in an alternating magnetic field may be understood in terms of several types of energetic barriers which must be overcome for reversal of the magnetic moments. With decreasing particle size, these barriers decrease and the probability of jumps of the spontaneous magnetization due to thermal activation processes increases. Accordingly, relaxation effects may be observed if the measurement frequency is smaller than the characteristic relaxation frequency of the particle system. The latter one may be understood in the frame of a model of two energy levels which are separated by an energy barrier being proportional to the anisotropy energy KV (V particle volume). Then, the so-called Neel relaxation time of the system is determined by the ratio of anisotropy energy KV to thermal energy kT (Neel, 1949)

Integral And Relaxation Pulse Frequency Modulation Models For The Spike Generator Locus

To model spike generation heuristically on a computer, there are two mathematical models that are considerably simpler than the HH equations. The simpler model for action potential generation as a function of a GP is called integral pulse frequency modulation (IPFM) (Li, 1961 Meyer, 1961 Pavlidis, 1964). A more realistic SGL model uses relaxation pulse frequency modulation (RPFM), in which the integrator is replaced with a simple, one-pole low-pass filter (Meyer, 1961). The properties and simulation of these simple SGL models are described below.

Three Kinds of Relaxation Occur in the Gastric Reservoir

Vagovagal Reflex

Neurally mediated decreases in tonic contracture of the musculature are responsible for relaxation in the gastric reservoir (i.e., increased volume). Three kinds of relaxation are recognized. Receptive relaxation is initiated by the act of swallowing. It is a reflex triggered by stimulation of mechanoreceptors in the pharynx followed by transmission over afferents to the dorsal vagal complex and activation of efferent vagal fibers to inhibitory motor neurons in the gastric ENS. Adaptive relaxation is triggered by distension of the gastric reservoir. It is a vago-vagal reflex triggered by stretch receptors in the gastric wall, transmission over vagal afferents to the dorsal vagal complex, and efferent vagal Adaptive relaxation in the gastric reservoir. P Adaptive relaxation is a vago-vagal reflex in which information from gastric stretch receptors is the afferent component and outflow from the medullary region of the brain is the efferent component. Vagal efferents transmit to the ENS,...

Endothelial Cells Can Release Chemicals That Cause Relaxation or Constriction of Arterioles

An important contributor to local vascular regulation is released by endothelial cells. This substance, endothelium-derived relaxing factor (EDRF), is released from all arteries, microvessels, veins, and lymphatic endothelial cells. EDRF is nitric oxide (NO), which is formed by the action of nitric oxide synthase on the amino acid arginine. NO causes the relaxation of vascular smooth muscle by inducing an increase in cyclic guanosine monophosphate (cGMP). When cGMP is increased, the smooth muscle cell extrudes calcium ions and decreases calcium entry into the cell, inhibiting contraction and enzymatic processes that depend on calcium ions. Compounds such as acetylcholine, histamine, and adenine nucleotides (ATP, ADP) released into the interstitial space, as well as hypertonic conditions and hypoxia cause the release of NO. Adenosine causes NO release from endothelial cells and directly relaxes vascular smooth muscle cells through adenosine receptors.

Myocyte Relaxation

Myocyte relaxation is a complex process whose rate is determined by three main factors the kinetics of crossbridge cycling (particularly the rate at which the crossbridges transition from a force-producing to a non-force-producing state), the affinity of Ca ions for TnC, and the activity and affinity of the main Ca reuptake and extrusion mechanisms.64,65 All else being equal, slower kinetics of crossbridge cycling, increased Ca affinity for TnC, and reduced activity of SERCA2 and or the Na-Ca exchanger slow relaxation. Relaxation is also modulated by the load on the myocyte, at least in part because of the aforementioned dependence of crossbridge cycling kinetics on load. As noted previously, relaxation also may be influenced by restoring forces generated by compression of titin.

Herbal Therapy And Nutritional Supplements

Botanical medicine or herbal therapy is a type of complementary alternative therapy that uses plants or herbs to treat various disorders. Individuals worldwide use both herbal therapy and nutritional supplements extensively. According to the World Health Organization (WHO), 80 of the world's population relies on herbs for a substantial part of their health care. Herbs have been used by virtually every culture in the world throughout history, from the beginning of time until now. For example, Hippocrates prescribed St. Johns Wort, currently a popular herbal remedy for depression. Native Americans used plants such as coneflower, ginseng, and ginger for therapeutic purposes. Herbal therapy is part of a group of nontraditional therapies commonly known as complementary alternative medicine (CAM). Unfortunately, CAM therapies are not widely taught in medical schools. A 1998 survey revealed that 75 of 117 US medical schools offered elective courses in CAM or included CAM topics in required...

Educating the Client on the Use of Herbs and Nutritional Supplements

The use of herbs and nutritional supplements to treat various disorders is common. Herbs are used for various effects, such as to boost the immune system, treat depression, and for relaxation. Individuals are becoming more aware of the benefits of herbal therapies and nutritional supplements. Advertisements, books, magazines, and Internet sites abound concerning these topics. People, eager to cure or control various disorders, take herbs, teas, megadoses of vitamins, and various other natural products. Although much information is available on nutritional supplements and herbal therapy, obtaining the correct information sometimes is difficult. Medicinal herbs and nutritional substances are available at supermarkets, pharmacies, health food stores, specialty herb stores, and through the Internet. The potential for misinformation abounds. Because these substances are natural products, many individuals may incorrectly assume that they are without adverse effects. When any herbal remedy...

Volitional Changes And Alterations In Voluntary Muscle Activity

Relaxation, paralysis, automatic movements and rigid catalepsy may all be experienced as avolitional changes in response to hypnotic suggestion. Enhanced muscle performance may also be reported, but this may be due to reduced perception of muscle fatigue, rather than to actual improved performance.

Muscle Function And Body Movement

During both simple and light-load skilled movements, the antagonist is relaxed. Contraction of the agonist with concomitant relaxation of the antagonist occurs by the nervous system function of reciprocal inhibition. Co-contraction of agonist and antagonist occurs during movements that require precise control.

Types of patient education

Preoperative education prepares the patient for the experience of surgery and what can be expected, by teaching relaxation and other coping skills that can reduce patient anxiety, length of hospital stay, postsurgical complications, use of pain medications, and overall hospital costs.

Study in Ileal Pouch Anal Anastomosis IPAA

In a study of some years ago 96 , our aim was to determine whether a meal induces specific motor patterns in longstanding IPAA. Nine patients (6M, 3F) aged 35-58 (median 49) years were studied 1-10 (median 6.8) years after ileostomy closure. Two had a W-pouch and seven had a J-pouch. None of the patients showed endoscopic findings of pouchitis daily bowel movements were 2-6 (median 4.6). After at least 12 h of fasting, an 8-channel perfused catheter with an open central lumen was placed by means of a guide-wire inserted during a regular colonoscopy. Recording ports, 15 cm apart, were positioned such that four were in the proximal small bowel, three in the reservoir and one on the internal anal sphincter. After at least 1 h after colonoscopy, we recorded pressure signals for 120 min before the ingestion of a 1 000-Kcal meal with 40, 30 and 30 of lipids, proteins and carbohydrates respectively. Postprandial recording continued for a further 60 min. Small bowel and pouch...

Magnetic Field in Condensed Matter Special Topics

In this section, we consider some special topics dealing mainly (but not only) with ferromagnetic materials various contributions to the magnetic energy of such materials, magnetic domains and domain walls, hysteresis phenomena, very small (so-called single-domain) ferromagnetic particles, and irreversible magnetic relaxation. Further, we briefly review the energy dissipation in alternating magnetic fields and discuss the possibility of a reconstruction of the magnetization distribution inside a body from magnetic field measurements outside it.

Who Are Our Hypnotic Clients Indications

In fact, patients are far more apt to present in our offices requesting an hypnotic intervention. We might then think of clients as falling into several categories. There is that group of clients who present with symptoms that are particularly amenable to an hypnotic intervention. Areas of increased use of hypnosis include stress reduction, pain management wellness, and uncovering work in a psychodynamic relationship. Many of these clients are sophisticated in their knowledge of alternative health benefits and ask for information on hypnosis, while others are aware of the benefits of stress reduction techniques such as relaxation exercises, meditation and guided imagery, but are uninformed about their similarity to hypnosis. Still others are uninformed about hypnosis and ignorant of its application to their problem. Those who are actively resistant to the idea of hypnosis pose a particular challenge to clinicians. Resistance may come from several sources. Religious and cultural...

Benefits And Limitations Of Mris

The principal assets of MRI are noninvasiveness, high spatial resolution, of the order of 100 fim for rodent studies, and excellent soft tissue contrasting capabilities. The MR signal is governed by a number of parameters, e.g., proton density, relaxation times (7 , T2, T ), proton exchange rates, water diffusion, macroscopic motion (blood flow), which depend on the biophysical properties of the tissue. This wealth of information renders MRI a valuable tool for diagnosis, tissue staging, and in vivo morphometry, for obtaining physiological and functional readouts, and for deriving metabolic and, to some extent, target-specific tissue characteristics (see Section 2.6 below) in a noninvasive manner.

Whatis The History Of Previous Treatments

In making the determination as to whether an hypnotic intervention is suitable for a client, it is important to learn whether the client has had any prior experience with hypnosis or other alternative health approaches such as meditation, relaxation tapes or guided imagery. When there has been previous experience, inquiry about the client's experience as to depth of trance, reaction to suggestions, and the client's measure of the success or usefulness of the previous interventions, will provide the clinician with valuable data. This feedback will be useful in several areas continuing to set positive expectancies for the client tailoring the hypnotic intervention to the individual needs of the client and correcting misinformation. Therapists report that when a previous experience with hypnosis has soured a client on the use of hypnosis, it may still be valuable to pursue the consideration of using hypnosis, patiently correcting misinformation and encouraging the client to reassess the...

Intrinsic Control Systems

Another important intrinsic control mechanism is the force-frequency relation (FFR)73-75 (Fig. 3-14). At a basal rate of 60 per minute, the duration of the myocardial twitch contraction is such that relaxation would be incomplete at rates achieved during exercise and cause impaired diastolic filling. Therefore, the myocardium must have mechanisms that automatically speed contraction and relaxation at rapid rates. In conjunction with this abbreviation of contraction, the strength of contraction is markedly enhanced, allowing maintenance of SV even though less time is available for filling and emptying. The mechanism of the positive FFR involves increased and more rapid Ca cycling per beat as frequency increases.8,59,76-79 Factors contributing to this include the direct effect of a greater number of APs per unit time, causing intracellular accumulation of Ca ions, as well as increases in SR Ca pumping. Thus Ca entry increases directly with more frequent opening of L-type Ca channels and...

Various Types Of Cells

These specialized cells form muscle tissues such as skeletal muscles to move joints, cardiac muscles to produce heartbeat, and smooth muscle tissues found around the internal organs and large blood vessels. Muscle cells produce mechanical force by their contraction and relaxation.

Shortterm Modulation Of Ventricular Function

The ventricle has a positive FFR with an optimal frequency that parallels the myocardial FFR.7475 As indicated earlier, this is an important means of modulating ventricular function that is intimately connected with changes in adrenergic stimulation. Changes in contraction frequency also influence relaxation and filling. There is some shortening of relaxation in conjunction with the positive FFR even without concurrent increases in adrenergic stimulation.73 Moreover, with increased HR, diastole is shortened much more than systole, especially the slow-filling phase. This has been discussed previously in the section on cellular control of contractility. It is important to emphasize that the significance of these factors with respect to norma1 ventricular function is not established. In the ventricle, these factors tend to have more prominent effects on relaxation than on contraction.161 NO and endothelial-dependent vasodilators cause very modest depression of systolic function and an...

Blood Volume and Blood Vessels

The vessels at various points in the circulatory path differ anatomically and functionally. The great arteries have thick walls heavily lined with smooth muscle and contractile tissue to enable them to transport blood under pressure from the heart to peripheral tissues. The arteries become smaller and thinner-walled as they branch out toward the periphery. The systemic arteries deliver blood to the microcirculatory beds of the tissues and organs. These capillary beds consist of microscopic arterioles, capillaries, and venules. The contraction (vasoconstriction) and relaxation (vasodilation) of the smooth muscles in the terminal branches of the arteries play an important role in regulating blood flow in the capillary bed. Control of the arteriole muscles is mediated by sympathetic neurotransmitters, hormones, and local effects. From the arterioles, the blood enters the capillaries, minute vessels whose walls consist of a single layer of cells, facilitating transfer of oxygen and...

The Measurement of Magnetic Fields

For many years, the primary position with regard to the greatest sensitivity or lowest value of detection limit was held by the SQUID principle this type of field sensor is described in detail in Section 2.2. More recently, the atomic magnetometer was developed with slightly higher sensitivity (Kominis et al., 2003 Schwindt et al., 2004). In addition, the optical pumped magnetometer could be used to map the human cardiomagnetic field (Bison et al., 2003). This new measuring principle is based on the detection of the so-called Larmor-spin precession of atoms which are excited by optical radiation. The sensitivity of the technique is essentially determined by the relaxation time which passes until the increased energy of the atoms is delivered to the surroundings.

Hazard Identification

The rate-limiting step in processing of antigen and presentation to the immune system appears to be unfolding of proteins at the cleavage site. Immunodominant epitopes are associated with structurally unstable protein segments associated with highly flexible polypeptide loops (Landry, 1997). These epitopes can be measured by NMR relaxation parameters.

Electronic Luminescence Spectroscopy

Luminescence spectroscopy deals with emission associated with a transition from an excited electronic state to a lower state (generally the ground state) (Lakowicz, 1999 Lakowicz, 1991-2000). Biological molecules at room temperature exhibit fluorescence. Phosphorescence from a triplet excited state to the singlet ground state is rarely observed at room temperature. One-photon absorption produces a fluorescence band that is red-shifted (to a lower energy). This shift between the peak of the absorption band and that of the fluorescence band is called Stokes shift. The amount of Stokes shift is a measure of the relaxation process occurring in the excited state, populated by absorption. The difference in the energy of the absorbed photon and that of the emitted photon corresponds to the energy loss due to nonradiative processes. The Stokes shift may arise from environmental effect as well as from a change in the geometry of the emitting excited state. Figure 4.9 shows the absorption and...

Cardiac Function Of The Hypertrophied Heart

Mechanical function of the hypertrophied heart has been studied at the isolated myocyte, muscle, and chamber levels and in the intact circulation.71-73 The results of these studies have revealed variable alterations in the rate and extent of contraction and relaxation, in the amount of force development, and in resting muscle and chamber properties. In the intact circulation, altered systolic and diastolic function is a composite result of subcellular changes in the myocyte, changes in the extracellular matrix, altered chamber geometry and mass, altered ventricular-vascular coupling, and the modulatory effects of neural and hormonal influences. The earliest changes in mechanical performance observed in isometrically contracting papillary muscles extracted from hypertrophied hearts consist of a prolongation of time to peak tension and relaxation, despite normal peak twitch tension normalized for cross-sectional area of the muscle.74 Afterloaded isotonically shortening papillary muscle...

Mechanisms For The Transition From Compensated Hypertrophy To Heart Failure

In contrast to hypertrophied skeletal muscle, chronically increased work eventually results in depressed contractility and relaxation of the hypertrophied heart. Compensated hypertrophy, which is characterized by abnormal chamber function but preserved muscle and myocyte function, evolves into a decompensated phase characterized by abnormal chamber, muscle, and myocyte function Fig. 5-1). Attempts to elucidate the underlying mechanisms for this transition

The Many Types of Magnetic Resonance Examination

Reformatting of the two-dimensional image in any plane and with any slice thickness. This is akin to the ability to reformat (or remontage) the electroencephalogram (EEG) data after it is acquired if it is acquired digitally. This is important for dealing with partial volume effects and for volume measurement techniques. Techniques are also available that can help to quantify tissue characteristics such as the T2 or T1 relaxation times. This requires different sequences and provides different information from that obtained with standard anatomic imaging techniques. MR can also identify biochemical aspects of a selected region of the brain by MR spectroscopy (MRS) and can provide low-resolution images of these metabolites using chemical shift imaging (CSI). These techniques can be used to identify specific metabolites and their relative concentrations in specific areas of the brain (Chapter 13).

Nondepolarizing neuromuscular blocking drugs

Muscle but do not cause depolarization. (They may also block prejunctional receptors responsible for facilitating the release of acetylcholine.) They are sometimes referred to as competitive neuromuscular blockers. The time to maximum effect, that is when relaxation is adequate to allow tracheal intubation, is relatively slow compared with suxamethonium, generally 1.5-3mins. A synopsis of the drugs used is given in Table 2.6. following suxamethonium to maintain muscle relaxation during surgery

Artificial control pats

These impacts are likely to be devastating for many insect species, with synergistic effects of pollution, pesticides, fragmentation, invasive aliens and global warming taking an immediate toll, followed in time by the effects of ecological relaxation as populations are gradually lost from the small remaining natural fragments.

Small Arteries Arterioles and Capillaries Account for 90 of Vascular Resistance

Serving a profile of the pressure drop along the vascular tree (Fig. 15.8). Little change in pressure occurs in the aorta and large arteries. Approximately 70 of the pressure drop occurs in the small arteries and arterioles, and another 20 occurs in the capillaries. Contraction and relaxation of the smooth muscle in the walls of small arteries and arterioles cause changes in vessel diameter, which, in turn, influence blood flow.

The Management Of Chronic Stress

Longer term it is desirable that the patient can manage the exaggerated phasic and tonic arousal via other strategies such as relaxation, meditation, self-hypnosis, biofeedback or exercise programmes. Relaxation meditation techniques if practised regularly have been shown to progressively lower the basal physiological arousal. There are many different approaches to meditation and relaxation (Jacob-son, 1929 Benson, 1975), but they essentially involve similar principles. The patient needs to be motivated to persist as it is the alteration of a habitual basal or Where stress is not the result of challenges being turned into threats, stress management may need to consider lifestyle changes. Constant, ongoing stimulation (even positive stimulation) may accumulate to manifest itself in a hyperarousal stress response. The patient needs to accept the requirement for restoration of biological and psychological homeostasis, or in other words the reduction of basal arousal back into the middle...

Adenosine And Related Compounds

Both adenine nucleosides (adenosine) and nucleotides (ADP and ATP) are released by the endothelium in response to such stimuli as thrombin94 and flow.92 Adenine nucleosides bind to P1 purinergic receptors that activate cyclic AMP leading to relaxation, whereas adenine nucleotides stimulate P2 receptors that are coupled to phosphoinositide hydrolysis. Stimulation of P2 receptors in endothelial cells results in an increase in intracellular Ca2+ and release of EDRF prostacyclin,93 whereas P2 receptors on vascular smooth muscle mediate contraction.94 Thus, depending on the relative amounts of adenosine, ATP, and ADP in the vessel wall, and the presence of a functional endothelium, these compounds can have a net dilatory or constrictor effect on vascular smooth muscle. Additionally, the endothelium possesses an extracellular ectonucleotidase enzymatic system that mediates the conversion of ATP or ADP to adenosine, thereby regulating the local levels of these compounds.45 These systems are...

Endothelialderived Inhibitors Of Smooth Muscle Cell Growth

That other endothelial cell factors may be involved. Another possibility is NO, which is usually associated with vascular relaxation. NO is released tonically from the endothelium of large arteries, which have a relatively minor role in the control of vascular tone, suggesting that it may have an additional function in these vessels. Studies on cultured VSMC have shown that pharmacologic agents such as sodium nitroprusside and 8-bromo-cyclic GMP, which mimic the effect of NO on vascular smooth muscle G kinase, can inhibit mitogenesis.108 This raises the possibility that NO may have an important role in maintaining the normal artery in a state refractory to mitogens. It is of interest that the myointimal proliferation in response to balloon injury can be inhibited by overexpression of NO synthase using gene transfer techniques.109'110 Finally, endothelial cells have been shown to make and secrete TGF-ft, which is subsequently activated by smooth muscle cells. This growth factor...

Tubes for synovial fluid analysis

Arthrocentesis Wrist

Comfortably extended to relax the quadriceps muscle. If one can gently rock the patella medially and laterally, relaxation is adequate. By grasping the medial and lateral margins of the patella, a skin mark can be made that corresponds to the inferior plane of the patella. It is generally easier to aspirate at the medial aspect of the joint. After the skin and subcutaneous tissue are anesthetized, a 19-gauge needle is introduced in a direction parallel to the plane of the posterior surface of the patella. With thick exudative effusions, a larger-bore needle may be required. Drainage of the knee bursa can be facilitated by compressing the suprapatellar pouch during aspiration. With large knee effusions, the distended suprapatellar pouch can be aspirated directly from either the medial or lateral aspect of the quadriceps muscle mass.

Necessary Attributes Of Small And Mediumscale Neural Models

The relaxation pulse frequency modulator (RPFM) is very similar to the IPFM system except that, instead of an integrator with infinite memory, the RPFM system inputs the SGP into a simple low-pass filter (LPF) with the transfer function, H(s) a (s + a). The output of the LPF then must exceed a firing threshold voltage, Vr with positive slope to initiate an output spike. As in the case of IPFM, the output spike resets the LPF output to zero. The RPFM system is not a linear voltage-to-frequency converter, and it has finite memory to transient SGP inputs.

Electronic Neural Models Neuromimes

The author and graduate students J.-M. Wu and E.F. Guignon, inspired by the work of Harmon and Lewis, designed and built their own neuromime computer in 1966. We followed Lewis's designs for synaptic loci, but developed our own SGL circuit using a unijunction transistor (UJT) relaxation oscillator that closely followed the IPFM architecture (Li, 1961). Our SGL circuit is shown in Figure 3.2.1. Note that the SGL is a current-controlled oscillator where the UJT firing frequency is nearly linear with the dc current leaving the input node. The capacitor C1 charges under constant-current conditions from the collector of the PNP BJT, Q1. When VC1 reaches the firing threshold for the 2N489 UJT, its gate conductance abruptly increases, discharging C1. A 6 V negative pulse about 100 s in duration is seen at the UJT B2. This pulse is reshaped by a one-shot (monostable multivibrator) circuit and given a low output impedance at the SGL output. Note that we used negative signals, i.e., a more...

Fourier Transform Ion Cyclotron Resonance Analyzers

Second altering trap plate potentials, in order to (a) inject or eject ions along magnetic field lines or (b) manipulate the z-amplitude of the ions. Third delaying events, that occur by not making changes in the electric fields and allowing time for (a) relaxation (homogeneous and inhomoge-nous) (b) collisions (dissociative and reactive) and (c) detection of the image current.

Herbal Alert Passion Flower

The term passion flower is used to denote many of the approximately 400 species of the herb. Passion flower has been used in medicine to treat pain, anxiety, and insomnia. Some herbalists use the herb to treat symptoms of parkinson-ism. Passion flower is often used in combination with other herbs, such a valerian, chamomile, and hops, for promoting relaxation, rest, and sleep. Although no adverse reactions have been reported, large doses may cause CNS depression. The use of passion flower is contraindicated in pregnancy and in patients taking the monoamine oxidase inhibitors (MAOIs). Passion flower contains coumarin, and the risk of bleeding may be increased when used in patients taking warfarin and passion flower.

Increasing Selfesteem Empowerment And Control

In discussing their clinical use of hypnosis for depression, Crasilneck & Hall (1985) state that 'our approach is to increase the patient's ego strength and to enhance his ability to deal with the problems leading to depression' (p. 324). Sachs (1992) describes the use of ego-strengthening achieved by hypnotically enhanced mental imagery, in conjunction with progressive relaxation in the management of cancer patients. McBrien's (1990) depression prevention programme utilizes self-hypnosis to produce an increased confidence in managing and reducing depressed feelings. Hypnosis is also used to increase the ability to experience positive thoughts and feelings that lead to an increase in pleasant events.

Nitric oxide is a gas that can act as a second messenger

Level of another second messenger, cyclic GMP (cGMP). This nucleotide bound to a protein kinase, which then stimulated a kinase cascade leading to muscle relaxation. So far, the pathway seemed straightforward. The spectacular discovery of NO as a second messenger explained the action of nitroglycerin, a drug that has been used for over a century to treat angina, the chest pain caused by insufficient blood flow to the heart. Nitroglycerin releases NO, which results in relaxation of the blood vessels and increased blood flow. Penile erection is also caused by the dilation of blood vessels in that organ, and the new drugs that promote erection are NO synthesis activators.

Severely Depressed Individuals Lack The Capacity To Utilize Hypnosis

Spiegel & Spiegel (1978) suggest that 'Those with serious depressions may be so narcissistically withdrawn and devoid of energy that they cannot attend to the input signals' (pp. 148-149). Others point to the difficulties in concentration and attention associated with severe depression, suggesting that these individuals are unable to focus on the induction process. Yapko (1992) talks about the way in which depression impairs the client's ability to focus. Rather than seeing this phenomenon as a contraindication for therapy, Yapko (1992) spends some sessions 'providing some general relaxation and focusing techniques to help build an attention span adequate to utilize in therapy'. He advocates the repeated use of session tapes as ongoing practice increases ability to focus meaningfully (p. 47).

Vasculature Endothelial Dysfunction

In a rat model of CHF, the addition of spironolactone to ACE inhibitor therapy normalized nitric oxide-mediated endothelial relaxation by beneficially modulating the balance of nitric oxide and superoxide anion formation (41). In the New Zealand rabbit, eplerenone improved endothelial function and reduced free radical stress in early atherosclerosis (42). In vitro studies suggest that aldosterone causes non-genomic vasoconstriction of rabbit pre-glomerular afferent arterioles via the protein kinase C and inositol (1,4,5)-triphosphate (IP3) pathways (9). This effect of aldosterone, which

Intracellular Distribution of the Imaging Probe

When the imaging probe is internalized into the cell, its effect may depend upon its location. To improve our insight into this issue, we have compared the relaxation enhancement measured for Gd-HPDO3A internalized in HTC (post-hepatocarcinoma cell line) by pynocytosis and by electroporation, respectively, 84 . Whereas the former route causes the entrapment of the contrast agent into endosomic vesicles, the latter one leads to its dispersion into the cytoplasm. Electroporation consists of the formation of transient hydrophilic pores on the cell membrane upon the application of suitable electric pulses between the two electrodes placed in the cell suspension 85 . As shown in Figure 4.9, the relaxation rate of the cells labeled by pynocytosis shows a saturation effect upon increasing the amount of the internalized Gd-HPDO3A with limiting Rj values of approximately 3 sConversely, the Rj values for the cellular pellets labeled by electroporation are markedly higher, and even more...

Caveolae and Membrane Tension Mechano Sensitivity and Mechano Regulation

Tension Caveolae

The morphological changes of caveolae with the tension of the plasma membrane provides the basis for mechanical regulation at the cell membrane. It is known that the tension of a cell increases if it is mechanically perturbed 32 , and that cells have developed regulatory mechanisms to accommodate mechanical perturbations 32,33 . Caveolae might play a role in this mechanism, and many pathologies associated with caveolin seem to involve the mechanical behavior of the cell. One can cite their involvement in various muscular diseases 34 , and defects in vascular relaxation and contractility in mice deficient of caveolin-1 4 . There is an increase of the number of caveolae in Duchenne muscular dystrophy 35 , and such an increase has also been observed in cells subjected to long-lasting shear stress 36 . Furthermore, there exists evidence that caveolin can contribute significantly to cell-cycle regulation 37 , and cell entry into mitosis can be inhibited by artificially maintaining a high...

Behavioral Conditioning Affects Cardiovascular Responses

Behavioral conditioning of cardiovascular responses has significant clinical implications. Animal and human studies indicate that psychological stress can raise blood pressure, increase atherogenesis, and predispose to fatal cardiac arrhythmias. These effects are thought to result from an inappropriate fight-or-flight response. Other studies have shown beneficial effects of behavior patterns designed to introduce a sense of relaxation and well-being. Some clinical regimens for the treatment of cardiovascular disease take these factors into account.

Hypnotic Induction For The Modification Of Hopelessness

And perhaps as you notice the heaviness of your body I wonder if you can discover that some of that heaviness that weighs you down is a sense of increasing relaxation and your wait can feel like an untying. Let yourself become aware of the point where the wait becomes the burden of curiosity As you look around in what seems like endless blackness I wonder if you can look closely enough to see the beginnings of new growth Because you know that Nature will always find a way to renew. Even when the landscape seems overwhelmingly barren it is always possible to find signs of change Because change can move so gradually perhaps you can begin to let yourself notice how much the comfortable weight of relaxation can seem lighter And the heavy darkness of night becomes the lightness of day because you know that there will always be a moving forward And you can discover yourself less tied to the darkness and increasingly aware of signs of the lightness ahead More and more, it will be possible to...

Identification of Plaque Components in the Vessel Wall by MRI

Findings from in vitro studies demonstrated the ability of MRI to identify various plaque components 65, 66 and T2-weighted sequences have shown promise for the differentiation of plaque components 65, 67 . Serfaty et al. 68 used T2-weighted MR imaging to measure fibrous cap thickness and lipid core volume. Unfortunately, their ex vivo study was limited by overestimation of the lipid core. Shinnar et al. 66 suggested the use of two echo times to differentiate the lipid core from fibrocellular areas that contain lipid. However, one limitation of T2-weighted MR imaging is an inherently low SNR. In vivo application of these techniques is supported by the strong agreement demonstrated between in vivo and ex vivo measurements of vessel wall thickness and T2 relaxation of plaque components 69, 70 . Wasserman et al. 71 used gadolinium (Gd) in combination with Tl-weighted MRI to describe plaque morphology and demonstrated not only that delayed hyperenhancement preferentially occurs in...

Display 251 Effects of the Cholinergic Blocking Drugs

Accommodation or inability to focus the eye) Respiratory tract-drying of the secretions of the mouth, nose, throat, bronchi, relaxation of smooth muscles of the bronchi resulting in slight bronchodilatation Gastrointestinal tract-decrease in secretions of the stomach, decrease in

Regulation of the Pulmonary Vascular Signaling System by ROS and RNS

Mechanical changes can influence 02' production. For example, alterations in the shear stress caused by increased blood flow promote endothelium-derived 02 generation in the pulmonary circulation (6). Local levels of 02 are also elevated during lung injury or distress conditions by an imbalance between its rate of formation and its rate of removal via SOD. When the concentrations of 02' rise over the nanomolar concentration range, it directly interacts with catecholamines (including the neurotransmitter norepinephrine and the hormone epinephrine) and NO, which inactivates the bioactivity of these mediators. 02 inhibits vascular relaxation to H202, which may be a result of 02 inhibiting the activity of catalase.02 inactivates glutathione peroxidase by oxidizing selenium and aconitase by interacting with iron-sulfur center in the enzyme resulting in increased oxidant stress and an impairment of mitochondrial function. Increased levels of 02' reductively release iron from the iron-sulfur...

Solutions To Exercises Lesson

A major function of the large intestines is to salvage water. To facilitate movement, mucus is added to the contents of the large intestines. Microorganisms in the large intestines manufacture vitamin K. Some microorganisms can act upon certain foods to produce gases. Feces is stored in the rectum and the lower portion of the sigmoid colon. Defecation is accomplished by relaxation of the anal sphincter muscles. (paras 6-35 thru 6-37)

Upper Airway Tone May Be Compromised During Sleep

A prominent feature during REM sleep is a general reduction in skeletal muscle tone. Muscles of the larynx, pharynx, and tongue share in this relaxation, which can lead to obstruction of the upper airways. Airway muscle relaxation may be enhanced by the increased effectiveness of the lung inflation reflex.

Concentration Response Curves

In vasodilator curves, each vessel is first contracted to 80 of its maximum using a suitable agonist, e.g., NE. Once the vessel starts to relax, subsequent doses of agonist should be added when the response has leveled off. In vasodilator curves a common problem is spontaneous relaxation, where the vessel will fail to maintain contraction and relax to baseline either before or during the CCRC. If this happens, the vessel should be washed with fresh PSS and allowed to rest before a further attempt is made.

D eTRT1x y sin a MX y M0x y 11 etrtxy cos a339

For a given repetition time and flip angle, the image intensity is determined by the local longitudinal relaxation time T1(x, y). Since at short repetition times with small flip angles a large signal can still be obtained, this pulse sequence is often referred to as FLASH (fast low angle shot Haase et al., 1986). With FLASH imaging it is assumed that the phase memory of the transverse nuclear magnetization has been lost at the end of the repetition interval since this is not true when the repetition interval is smaller than the transversal relaxation time, spoiling gradient pulses must be applied at the end of each interval in order to prevent the emergence of coherent image artifacts. An alternative is to add a stochastically varying jitter to the repetition interval. In order to obtain an imaging sequence that actually uses the phase memory of the spins in order to yield a stronger signal at rapid repetition, and also to obtain information on the local transversal relaxation time,...

Negativefeedback Path

How might the changes in orientation of Listing's planes be accomplished Physiological studies indicate that simple gain changes of the obliques and perhaps the vertical recti might be involved. Mays et al. (1991) found that convergence-dependent changes of cyclovergence with gaze elevation were associated with a reduced discharge rate of trochlear motor neurons and an implied relaxation of the superior oblique muscle during convergence. The modulation of trochlear activity with convergence varied systematically with gaze elevation, and was largest in downward gaze. The fact that these authors observed no net increase in trochlear activity when the eyes incyclorotate with eye elevation during convergence indicates that the forces of other vertical ocular muscles were modulated during convergence to account for torsional adjustments in upward directions of gaze. Enright's measures of ocular translation also suggested that the superior oblique relaxes during convergence (Enright, 1992).

Micturition Involves Autonomic and Somatic Nerves

Micturition (urination), the periodic emptying of the bladder, is a complex act involving both autonomic and somatic nerve pathways and several reflexes that can be either inhibited or facilitated by higher centers in the brain. The basic reflexes occur at the level of the sacral spinal cord and are modified by centers in the midbrain and cerebral cortex. Distension of the bladder is sensed by stretch receptors in the bladder wall these induce reflex contraction of the detrusor and relaxation of the internal and external sphincters. This reflex is released by removing inhibitory influences from the cerebral cortex. Fluid flow through the urethra reflexively causes further contraction of the detrusor and relaxation of the external sphincter. Increased parasympathetic nerve activity stimulates contraction of the detrusor and relaxation of the internal sphincter. Sympathetic innervation is not essential for micturition. During micturition, the perineal and levator ani muscles relax,...

Contrast in MR Imaging

Variations in local relaxation times 7 and T2, and the amount of hydrogen nuclei per unit volume (known as proton density or N(H)) are the predominant sources of contrast in proton MRI. The use of local relaxation times for identification of pathology by MRI was inspired by the observation that malignant tissue can have longer T and T2 than normal tissue 2 . Although the relaxation properties of 1H nuclei in tissue are not completely understood, there is evidence that the pathological states of different tissues are characterized by specific biochemical processes that can alter relaxation times and proton density 3,4 , image contrast and NMR relevant tissue parameters, such as inherent relaxation times and proton density.

Therapeutic Intervention With Hypnosis

When evaluating a new patient, I listen to the patient's communication regarding dysphoric feelings of helplessness, anxiety, hopelessness, inner tension, insomnia, fear, restlessness, and so on. I introduce the idea of using hypnosis by making it relevant to the patient's presenting symptoms, saying to the patient something like this, 'Would you like to learn an exercise of how to reduce your anxiety and promote a sense of calmness and relaxation ' Patients generally respond affirmatively. I then proceed by teaching the patient a self-hypnosis exercise loaded with suggestions and images of calmness and comfort, asking the patient to select a place associated in their mind with such feelings. Some patients select a mountain trail, an inland lake or a state park, many select an ocean beach.

Assessment of Diastolic Function

Diastolic dysfunction is the hallmark of diabetic cardiomyopathy and echocardi-ography is invariably the most commonly employed test at the present time to reliably assess diastolic functional abnormalities. Left ventricular diastolic filling abnormalities in patients with diabetes do not correlate with the duration of diabetes nor with the presence of other complications such as retinopathy, nephropathy, or peripheral neuropathy. In diabetic cardiomyopathy, the initial abnormality of diastolic filling is characterized by a slowed or impaired myocardial relaxation as is the case for most other cardiac diseases. It should be noted that there is a gradual impairment of myocardial relaxation with normal aging, but in pathological states it is more pronounced than what is usually expected for the patient's age. With continued progression of the disease, LV compliance is reduced and elevation in left atrial pressure results in a restrictive LV filling pattern, which initially may be...

Allergic Reactions In The Skin

Introduction of allergens into the skin induces the immediate release of histamine from tissue-bound mast cells. Histamine activates venule endothelial cells by interacting with surface receptors. Activated endothelial cells initiate synthesis ofPAF and nitric oxide that induce relaxation of the vasculature. Red cells accumulate in the area creating a characteristic redness (erythema) in the skin. Concurrently, the endothelial cells retract creating openings in the venules. Plasma leaks from the vessel into the skin inducing edema or swelling in the skin (wheal). Bloodvessels at the periphery of the wheal often dilate creating a flare (Mathews, 1990).

Concrete Applications Of Hypnotic Techniques

BEGINNING PHASE Teaching Relaxation Many obese patients are often very tense and have learned to reduce this tension through excessive eating. It is therefore useful to teach a self-hypnosis exercise for relaxation and as an alternative coping strategy for overeating. Patients will be strongly encouraged to practice their self-hypnosis daily by means of an audiocassette. To introduce hypnosis, we use a classical induction technique with eye fixation and deepening suggestions. Next, the patient will be asked to imagine herself in a safe, secret place, wherein she can become even more and more relaxed and further reflect upon the things in her (or his) life that are important right now. 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....

Hypnosis In Enhancing Anxiety Reduction

While relaxation is not a requirement of hypnosis, the use of hypnosis can facilitate relaxation and reduction in the anxiety which may directly or indirectly impair sexual functioning. Hypnotically cued relaxation may be utilized at the time of sexual intimacy, during self-stimulation or during the sensate focus or pleasuring technique, a process of in vivo desensitization. This use of cued relaxation may also overcome the anxiety accompanying sexual guilt. Alternatively hypnotically based relaxation may be added to systematic desensi-tization in imagination, if in vivo work is not practical, for example when the patient does not currently have a partner. In fact Wolpe (1958), in his original account of systematic desensitization in imagination, utilized hypnotically based relaxation techniques, without further discussing the role hypnosis played.

Vascular Endothelial Function and ACE Inhibition

The predominant tone of a vascular bed is the sum of simultaneously acting vasodilator and vasoconstrictor influences. In normally functioning endothelial cells, a basal rate of production of NO is maintained by the action of the constitutive enzyme NO synthase (22). This basal production, which requires a normal endothelium, maintains a net vascular relaxation. However, various vasoactive substances (i.e., bradykinin, serotonin, adenosine diphosphate, and substance P), as well as the effect of blood's shearing force on the endothelium, can up-regulate NO synthase activity, increasing production and secretion of NO (23-25). NO inhibits cellular growth and migration. In concert with prostacyclin, NO exerts potent anti-atherogenic and antithrombotic properties by preventing platelet aggregation and cell adhesion (21).

Conclusion and Future Outlook

In recent years, DWI has undergone rapid growth and development, such that the technique has escalated rapidly from an experimental tool to an established clinical methodology, the primary use of which has been in the evaluation of acute cerebral ischemia. Much like T1- and T2-relaxation, diffusivity can be thought of as an intrinsic tissue property. Thus, DWI may also be useful in imaging extracranial organs, such as the solid organs within the abdomen, or abnormalities in the musculoskeletal system. The ability to determine diffusion coefficients in vivo has great potential for furthering our understanding of normal and abnormal physiology, as well as for characterizing focal and diffuse disease within the human body. Historically, bulk physiologic motion has hampered the application of DWI to a wide variety of clinical questions. However, developments in MR hardware, pulse-sequences and computer science - all enhanced by the rapid evolution of parallelimaging improvements - have...

Potential and Challenges with Ultrahigh Field MRI

These potential advantages are offset not only by the increased cost for large high-field magnets, but by several fundamental physical conditions that presently pose serious challenges for ultrahigh field MRI, including artifacts from inhomo-geneous B0 and B1 fields, different tissue relaxation times, and safety concerns.

Evidence of Detrimental Effects of Air Space Collapse

On the cellular level, the consequences of controlled deformation on the alveolar epithelial viability were assessed in an in vitro model 34 . In this model, repetitive stretching of alveolar epithelial cells was more damaging than tonically held deformations. For the same maximum deformation, any reduction of the amplitude of cell deformation (obtained by increasing the tonic or sustained deformation during the relaxation phase) significantly reduced damage as compared with full range or large-amplitude deformations. These data suggest that prevention of cyclic air space deflation to low volumes followed by re-expansion by means of enough end-expiratory pressure might reduce injury.

Quantitative Measurements of Hippocampal Sclerosis

Also, just because a measurement is reported as a number does not necessarily mean that it is a totally objective measurement or that a high degree of subjective skill is not needed for the acquisition of that number. Similarly, once a number is derived, we can become totally oblivious to the assumptions and compromises that went into acquiring that number, and mistakenly confuse it with objective reality. What this means, really, is that if you use numbers to make decisions, you need to know something about how they were acquired, what they mean, and what their limitations are. This is also true of such statistically based methods as voxel-based morphology and relaxometry (discussed below). In the context of temporal lobe epilepsy these numbers (hippocampal volumes and T2 relaxation times) are a means of reaching a diagnosis, and trying to standardize information and objectify the thresholds at which significant abnormality is diagnosed. As in all medical measurements, the clinical...

Normal Aging and Alzheimers Disease

It is well known that tissue iron content varies among different regions of the brain, and also changes with aging (Hallgren and Sourander, 1958). Paramagnetic tissue iron changes MRI relaxation times due to the diffusion of water molecules in the susceptibility field of the iron inclusions, and ultrahigh field MRI is particularly sensitive in this respect. Comparative contrast differences in T2-weighted brain images of two subjects aged 27 years and 50 years at 1.5 Tand 7 Tare shown in Figure 3.65. For example, gray matter in the motorsensory cortex has a lower signal than adjacent white matter, and this difference is more pronounced in older than in younger subjects, whereas contrast is inverted in the frontal and temporal cortices. The signal is lowest in the globus pallidus, substantia nigra, red nuclei and caudate, all of which have much higher iron contents. Quantitative measurements of T2-values exhibit a linear relationship to iron content computed from published values for...

Conclusion and Outlook

Bottomley, P.A., Foster, T.H., Argensinger, R.E., and Pfeifer, L.M. (1984). A review of normal tissue hydrogen NMR relaxation times and relaxation mechanism from 1-100 MHz - Dependences on tissue type NMR frequency, temperature, species, excision and age. Med. Phys., 11, 425-448. Gelman, N., Gorell, J.M., Barker, P.B Savage, R.M., Spicklee, E.M., Windham. J.P., and Knight, R.A. (1999). MR imaging of human brain at 3.0 T preliminary report on transverse relaxation rates and relation to estimated iron content. Radiology, 210. 759-767. Georgiades, C.S., Itoh, R., Goiay, X., van Zijl, P.C.M., and Melhem, E.R. (2001). MR imaging of the human brain at 1.5 T Regional variations in transverse relaxation rates in the cerebral cortex. Am. J. Neuro-radiol, 22, 1732-1737. Glover, G.H. (1999). 3D z-shim method for reduction of susceptibility effects in BOLD fMRI. Magn. Reson. Med., 290-299. Jensen, J.H., Chandra, R., and Yu, H. (2001). Quantitative model for the interecho time dependence of the...

Muscle Response Rates

Asynchronous muscles are not directly attached to the wings of the insect. Elevator muscles are attached to the roof of the thorax. Their contraction pulls the roof of the thorax down and elevates the wings. Contraction of the wing depressor muscles pulls down the wings, but this stretches the wing elevators, stimulating them to contract and allowing the thorax roof to pop up. Raising the thorax shortens the wing depressor muscles and terminates the active state of the depressors. They relax until stretched again by the elevation of the wings. The elevator and depressor muscle contractions follow the same sequence of stretch contraction shortening relaxation stretch, but are out of phase with each other. The frequency of wing beats depends upon the

Contraindications Precautions And Interactions

The peripheral vasodilating drugs are contraindicated in patients with known hypersensitivity to the drugs, women in the immediate postpartum period (isoxsuprine causes uterine relaxation), and in patients with arterial bleeding. Safe use during pregnancy has not been established (Pregnancy Category C). Cilostazol is contraindi-cated in patients with CHF and during pregnancy (Pregnancy Category C). These drugs are used cautiously in patients with bleeding tendencies, severe cerebrovascu-lar or cardiovascular disease, and after a myocardial infarction. There are no significant drug-drug interactions.

Muscles In Vertebrates

A specialized function twitch a rapid muscular contraction followed by relaxation that occurs in response to a single stimulus voluntary capable of being consciously controlled The ability of vertebrates to move their bodies and many of the contents of their bodies is a feature of major importance for their survival. The movements result from the contractions and relaxations of tissues specialized for the active generation of force the muscles. Although initially it may seem sufficient to have only one type of muscle tissue, reflection on the functional requirements makes it clear that more than one type of muscular tissue is probably necessary. For example, the movement of the limbs should be under the conscious, voluntary activation and control of the animal. Otherwise, unwanted and uncoordinated random limb movements would result, or desired and possibly vital movements would not be forthcoming. In addition, the control of the limb movements should be precise, with as wide a range...

Observing Hippocampai Sclerosis Development

Whereas the studies reported above consist of case reports or small series, one recent report assessed a series of 35 children (298). All had MR investigations within 5 days of a generalized status epilepticus. Quantitative assessments included T2 relaxometry and hippocampal volumetry. T2 relaxation time was elevated in patients with prolonged febrile convulsions compared with control subjects when they were scanned within 2 days of the acute event, whereas no difference in the T2-values were found in patients examined 3-5 days after the event. These findings are consistent with another series in children, scanned within 14 days of the event (299). In this series, T2 relaxometry findings showed no abnormalities.

Rho Rhokinase in Ca2 Sensitization and Pulmonary Vasoconstriction

VSMC tone is regulated by phosphorylation (causing contraction) and dephosphorylation (causing relaxation) of the 20-kDa regulatory MLC. Phosphorylation of MLC is catalyzed by Ca2+ calmodulin-dependent MLC kinase (MLCK) and dephosphorylation by Ca2+-independent MLC phosphatase (MLCP) that is targeted to myosin by its regulatory MBS. Thus, the balance in activities of MLCK and MLCP regulates contraction. At a given level of cytosolic Ca2+, the activity of both enzymes can be modulated by second messenger-mediated pathways to change MLC phosphorylation and force, i.e., to change theCa2+ sensitivity of contraction. There are multiple mechanisms of Ca2+ sensitization, but two major pathways lead to inhibition of MLCP and increased phosphorylation of MLC one by Rho-kinase-mediated phosphorylation of the MBS, and the other by PKC-mediated phosphorylation and activation of the 17-kDa MLCP-inhibitor protein CPI-17 (61). CPI-17 is also phosphorylated by Rho-kinase, and recent studies suggest...

Transition From Acute To Chronic Pain Anxiety To Depression

The management of acute pain (including some aspects of terminal cancer pain and chronic transient headaches Evans, 1989) involves the direct management of anxiety. The growing anxiety about the short- and long-term consequences of an injury or illness which accompanies the increasing intensity of the noxious stimulation is usually relieved by adequate treatment such as pain medication, hypnosis, or any other intervention that reduces anxiety, facilitates relaxation and refocuses attention (Evans, 1990b, 2001).

Assessing Cannabis Craving in a Research Setting

At the conclusion of a session, participants should undergo a debriefing session to reduce potentially heightened craving. The debriefing session entails 10-15 min of guided progressive relaxation. This procedure involves alternatively tensing and relaxing the major muscle groups of the body (e.g., neck, shoulders, arms, legs). As the various muscle groups are tensed and relaxed, the person is encouraged to note the difference between muscle tension and relaxation. Relaxation has been shown to reduce craving in the laboratory (6,9,10). Participants should not be released from the laboratory until their self-reported cravings at the end of the relaxation session are less than or equal to their craving levels at the start of the session.

Cell Tracking to Assess the Efficacy of Cellbased Therapies

Two factors contribute to the attractiveness of using MRI techniques for cell tracking studies (1) the high temporospatial resolution provided by MRI and (2) the potentially high payloads of labels that can be achieved for a cell without affecting its vital functions (see Chapter 25 for more details). This overcomes in part the inherent sensitivity issues associated with MRI. Cell trafficking studies can be applied to qualitatively monitor the migration of cells within the intact organism. This has been discussed in the previous section with regard to the evaluation of stem cell therapies in stroke. Alternatively, quantitative assessments are feasible by either measuring the volume occupied by the labeled cells 82 or by estimating local cell densities via quantitative analyses of relaxation effects. The concentration of contrast agents can be estimated based on their effects on tissue relaxation rates according to with Tt and Tto (i 1,2) being the tissue relaxation times measured...

Case Study for Chapter

A 51-year-old woman is evaluated for difficulty in swallowing solid foods. She experiences chest pain while attempting to eat and often regurgitates swallowed food. Fluoroscopic examination of a barium swallow reveals a dilated lower esophagus with considerable residual barium remaining after the swallow. A manometric motility study of esophageal motility following a swallow reveals an absence of primary peristalsis in the distal third, without relaxation of contractile tone in the lower esophageal sphincter. 2. What is the most likely explanation for the failure of the lower esophageal sphincter relaxation during the swallow

In Patients With Diabetes

Accordingly, when diabetic patients have CHF in association with coronary artery disease, they typically have conventional manifestations of myocardial ischemia (i.e., acute and chronic infarction, stunned and or hibernating myocardium) that result in both systolic failure, characterized by a reduced ejection fraction and ventricular chamber dilatation (when the process is chronic), and diastolic failure, characterized by upward displacement of the diastolic pressure-volume relationship due to slowed or incomplete relaxation and or decreased passive compliance (with or without a decrease in ejection fraction). In addition, remodeling of noninfarcted myocardium in patients with chronic infarction may also contribute to systolic failure. A depressed and even inverted FFR is a common manifestation of ischemic as well as nonischemic dilated cardiomyopathy. In view of the manifestations of and mechanisms underlying diabetic cardiomyopathy discussed above, it is not difficult to envision...

Modeling Of Enzymatic Processes In Thin Layers

Concentration of an inhibitor away from the cell surface. Given tissue growth rates of a few millimeters per day, control mechanisms should operate on the scale of about a few hundred seconds if the active zone is 10 microns wide. Diffusion coefficients for molecules in aqueous solution range from about 10-5 to 10-7 cm2 sec as the molecular weight rises from 50 to 500,000. For a film of thickness 10 microns, these give relaxation times for equilibration of concentration of about 0.5 to 5 seconds. Thus a diffusion-based control system would require diffusion coefficients reduced by two orders of magnitude. This could be the case in a gel matrix, if either the diffusing species bound to the gel or were large compared to the pore size of the gel. Either of these may be true for proteins diffusing in extracellular matrix.

Correlation of Hippocampal T2signal Increase with Hippocampal Volume Deficit

In contrast to elaborate volumetric assessment, the measurement of T2 relaxometry is a quick technique and can be implemented in large studies and measured routinely by the radiographer or reporting radiologist (319). The measured value of both hippocampal volume and the T2 time are inversely correlated with each other (218, 247, 318, 320). The inverse correlation between T2 signal and hippocampal volumes is present in the ipsilateral hippocampus but not in the contralateral hippocampus (318). This indicates that a marked volume loss is associated with a significant increase in T2 relaxation time, or in other words that an atrophic

Heart Failure with Normal Ejection Fraction

The presumption is that patients with CHF and normal ejection fraction have elevated cardiac filling pressures reflecting diastolic dysfunction that is in turn caused by slowed or incomplete myocardial relaxation and or decreased passive compliance. This is obvious in patients with constrictive pericarditis and restrictive cardiomyopathy, who have major structural impediments to ventricular filling. However, the more commonly encountered patients with underlying concentric hypertrophy also have abnormalities of relaxation and filling, including possible depression of sarcoplasmic reticulum calcium pumping, increased ratio of wall thickness to chamber volume, and very likely increased myocardial connective tissue. In addition, concentric hypertrophy is a substrate for subendocar-dial ischemia when energy demands increase even in the absence of coronary artery disease. Patients with underlying concentric hypertrophy and CHF with normal ejection fraction present typically with acute...

Quantitative Extrahippocampal Abnormality in Patients with Epilepsy

The vast majority of quantitative MR studies using T2 relaxometry are focused on the hippocampus in patients with pathologically proven HS. Changes in other areas have also been documented. Amygdaloid changes were assessed in a study of 29 patients with newly diagnosed and 54 patients with chronic temporal lobe epilepsy. In the newly diagnosed patients, the mean amygdaloid volume did not differ from that in controls. The mean T2 relaxation time in newly diagnosed or chronic patients did not differ from each other or from control values. However, unilateral T2 time of the amygdala was prolonged in 12 (171). T2-weighted signal abnormalities have also been observed in the anterior temporal lobe of TLE patients (252, 330), although their etiology and relevance is not known. We have recently observed T2 relaxometry changes outside the ipsilateral hippocampus of patients with HS, affecting the subcortical structures. These observations suggest that the structural signal abnormality in HS is...

Measuring Maximal Oxygen Uptake Is the Most Common Method of Quantifying Dynamic Exercise

Dynamic exercise is defined as skeletal muscle contractions at changing lengths and with rhythmic episodes of relaxation. Fundamental to any discussion of dynamic exercise is a description of its intensity. Since dynamically exercising muscle primarily generates energy from oxidative metabolism, a traditional standard is to measure, by mouth, the oxygen uptake (Vo2) of an exercising subject. This measurement is limited to dynamic exercise and usually to the steady state, when exercise intensity and oxygen consumption are stable and no net energy is provided from nonox-idative sources. Three implications of the original oxygen consumption measurements deserve mention. First, the centrality of oxygen usage to work output gave rise to the now-standard term aerobic exercise. Second, the apparent excess in oxygen consumption during the first minutes of recovery has been termed the oxygen debt (Fig. 30.1). The excess oxygen consumption of recovery results from a multitude of physiological...

Specific Pain Control Techniques

Suggestions of deep relaxation in themselves may reduce the anxiety that often accompanies pain. These suggestions can be enhanced by providing imagery under pleasant environmental conditions, with as much visual and sensory imagery as possible. For example, asking patients to imagine that they are in a mountain cabin in the snow can be therapeutic in itself or it can lead to the production of 'glove anaesthesia'. This may occur when patients are asked to imagine going for a walk in the snow, picking up a handful of snow, holding it to the pain area and then transferring the cold and numbness to replace the pain.

What Is The Relationship Between Domestic Stresses And Work

This demands a fairly focused and very self-conscious daily regime of healthy eating and getting plenty of exercise and sleep. This seeds a feeling of relaxation and well-being and the inner strength and resilience to cope with often unexpected bumps in life.

Sclerosis of the Amygdala

The majority of quantitative MR studies using T2 relaxometry are focused on the hippocampus in patients with pathologically proven HS. Changes in other areas, particularly the amygdala, have also been documented (165-167, 171, 172, 178, 236, 334). Amygdaloid changes were assessed in a study of 29 patients with newly diagnosed and 54 patients with chronic temporal lobe epilepsy. In the newly diagnosed patients, the mean amygdaloid volume did not differ from that in controls. The mean T2 relaxation time in newly diagnosed or chronic patients did not differ from each other or from control values. However, unilateral T2 time of the amygdala was prolonged in 12 (171).

Physiology of the Fetal Pulmonary Circulation

K+-channel activation appears to modulate basal PVR and vasodilator responses to shear stress and increased oxygen tension in the fetal lung, and may be particularly important in relaxation responses in resistance vessels. Whether this is partly related to EDHF activity remains unknown.

Artifacts Due To Magnetic Field Nonuniformity

For simplicity we will confine our discussion to the case of 2D gradient-echo imaging considered in Chapter 3. The magnetic field B' gives rise to the spatially-varying phase of the transverse magnetization < j> Jt, where J 7B'. A general equation describing the signal acquired in the presence of T2 relaxation and dephasing of spins caused by the field inhomogeneity B' can be written as where kx 7Gxt and ky *yGytph Gx and Gy are the readout and phase-encoding gradients, respectively t nrw and n changes from N 2 to N 2 - 1 TE is the echo time (see Chapter 3). To simplify our analysis we neglect T2 relaxation and assume that B' can be approximated as a sum of constant and linear terms B' a + G'xx + G'yy + G'zz. Using these assumptions we obtain from (6.1.2)

Long Term Effects ofET1 on Blood Vessels in Experimental Hypertension

We recently created a genetically engineered mouse that transgenically expresses human preproET-1 limited to the endothelium (by use of the endothelium-specific promoter Tie-2) (23). This induced a phenotype that, in the absence of significant blood pressure elevation, was associated with small artery hypertrophic remodeling and endothelial dysfunction, in support of our previous proposal that ET-1 induced vascular hypertrophy directly and independently of blood pressure elevation (19,20). Interestingly, NADPH oxidase activity was enhanced, indicating increased generation of superoxide anion that could contribute to the decreased endothelium-dependent relaxation through reduced NO bioavailability.

BProprioception Muscle Sense

(2) Another stretch receptor associated with the skeletal muscle is the Golgi tendon organ. As its name implies, this organ is located within the tendon of the muscle. The Golgi tendon organ is located in the tendon near its attachment to the muscle fibers. Thus, it detects relative muscle tension. Its threshold is higher than that of the muscle spindles in other words, there must be proportionately more contraction before it puts out a signal. Thus, when the muscle has been stretched excessively and might be subject to injury, its afferent neuron carries the message to the CNS. This results in relaxation of the muscle.

Arteries and arterioles have abundant elastic and muscle fibers

Smooth muscle cells in the walls of the arteries and arte-rioles allow those vessels to be constricted or dilated. When the diameter of the vessels changes, their resistance to blood flow changes as well, and the amount of blood flowing through them changes as a result. By influencing the contraction and relaxation of the smooth muscle in the vessel walls, neuronal and hormonal mechanisms can control the resistance of the vessels and therefore the distribution of blood to the different tissues of the body. (We'll see how these mechanisms work later in this chapter.) The arteries and ar-terioles are referred to as the resistance vessels because their resistance can vary.

Cytokines in Innate Immunity

Circulatory collapse is induced by several different mechanisms. Using the nitric oxide synthase enzyme, TNF induces the production of NO that decreases myocardial contractibility. Relaxation of smooth muscle and vascular tone further depresses blood pressure and tissue perfusion. Finally, TNF shifts the activity of procoagulants and the upregulation of endothelial adhesion factors. Both factors induce clotting and the occlusion of blood vessels by neutrophils attaching to the endothelium (Beutler and Grau, 1993).

The Original Technique First Pass Bolus Mapping of Changes in rCBV

The first functional MR images were collected by Belliveau and colleagues at the Massachusetts General Hospital (MGH) around 1989 and 1990 and published in 1991 1 . The technique these investigators chose to use was one that had also been pioneered at the MGH (no accident) 63 using intravenous administration of a bolus of paramagnetically labeled salt, Gd(DTPA)2. This technique allows the measurement of relative cerebral blood volume based upon the fact that the contrast agent remains in the intravascular space. Since the contrast agent is chosen to have a high magnetic susceptibility a large gradient is induced between the blood and the brain tissue. These gradients, which spread out far beyond the actual spatial volume distribution of the blood vessels, decrease in turn the relaxation rates of the water spins that diffuse through the gradients thereby affecting a relatively large proportion of the total water signal (i.e., in excess of the actual CBV). This renders the technique...

Is The Pain In The Main Plainly In The Brain

Effectively managing TMD requires a two-pronged approach of physically eliminating the noxious dental stimulus and mentally relaxing the muscles of mastication and muscles of facial expression. The use of medication and massage of sore muscles may expedite the healing process. Treatment of the physical etiology may be as simple as polishing fillings that have expanded with the course of time. Other treatment options may range from wearing a specially designed 'bite guard' appliance during sleep (or when stress is experienced during the day), to comprehensive orthodontic treatment and full mouth reconstruction with dental implants, crowns and bridges. But it may be impossible to determine the proper bite relation as long as the supporting muscles are in the clenched or braced posture. Resolution of the disorder requires a coordinated effort. The patient needs to learn how to relax the muscle of mastication and the dentist needs to adjust the bite for optimal comfort. Learning how to...

Nitrous Oxide Conscious Sedation

Nitrous oxide has been shown to emulate and enhance the hypnotic state. Goepherd et al. (1985) wrote that when hypnotic suggestion is combined with nitrous oxide, in general the patient is able to attain a therapeutic state of relaxation, euphoria and or sedation with decreased levels of nitrous oxide. In addition the use of nitrous oxide enhances the patient's response to suggestion even in an otherwise resistant patient. As well as its apparent trance-inducing effects, the gas also preserves both deep tendon and protective reflexes, and the airway is maintained in a clear state.

Anesthetic Considerations

Suprapubic prostatectomy can be comfortably performed with the patient under a general or regional anesthetic. With respect to the latter, options include a continuous spinal or epidural anesthetic. Regional anesthesia is advantageous because it is an excellent skeletal and smooth muscle relaxation, airway-related complications (unexpected coughing, gagging, or bucking) can be mostly avoided, and postoperative hemostasis is enhanced in because the patient is more comfortable and tranquil patient (1). Potential disadvantages include a history of documented central or peripheral neurologic deficits after the use of regional anesthetic, potential bleeding tendencies associated with this method, documented chronic low back pain after receiving regional anesthetic, spinal stenosis and or severe degenerative disk disease after regional anesthetic, and associated osseous metastasis (6). In addition, patient acceptance is low. Given the need for prolonged exaggerated lithotomy necessary to...

Assessment Of Systolic Function By Twodimensional Echocardiography

In an attempt to refine and facilitate the derivation of LV volume measurements from echocardiography, a number of technical developments have been evaluated. Images of the power spectrum of the Doppler signal produced by contraction relaxation and colorization of the B-mode tissue image have been utilized to visualize the endocardial surface.46 These techniques have been reported to be useful in identifying endocardial signals, particularly in patients with suboptimal tissue images. Greater enhancement of endocardial border delineation and improvement of the reliability of measures of LV size and contraction has been achieved through utilization of tissue harmonic imaging and by the injection of ultrasonic contrast agents to produce LV cavity opacification.18a46a A software package that provides instantaneous and automated endocardial border delineation throughout the cardiac cycle has been developed based upon the display of tissue signals as backscatter rather than specular...

Altered States Of Consciousness External Influences

Narcotic drugs are agents that relieve anxiety, produce relaxation, or reduce pain. Abuse of the two most common narcotic drugs, heroin and morphine, has become widespread. Initial misuse of narcotics commonly occurs for social reasons, but repeated dosages lead to a physiological dependence that continues to increase. This dependence has two aspects, the need for larger doses to prevent withdrawal symptoms (which can be quite severe) and the need for larger doses to produce the euphoric effect. Often, satisfaction of these needs leads to illegal activities to procure the narcotic. A hypnotized individual accepts the hypnotist's directions, showing little or no emotional feeling (unless prompted to do so) and increased suggestibility. The hypnotist usually can restrict or direct the subject's attention. Furthermore, a hypnotized subject may experience a distorted perception of reality or show pronounced relaxation or alertness, depending on the hypnotist's...