Peripheral muscles

Muscle biopsy shows some features in common with JDM for example, perifascicular atrophy resulting from preferential involvement of peripheral muscle fibers is seen in some cases of ADM whereas it is never seen in adult PM. Since... 

Fatigue of muscles is found post-exercise and in some patients with disorders of limb or respiratory muscles. Peripheral muscle fatigue is generally characterized by the changes in force frequency relationships that occur. The process is traditionally divided into a failure of force production at either low or high frequencies of electrical stimulation. 

Metformin is the only biguanide available in the United States. It enhances insulin sensitivity of both hepatic and peripheral (muscle) tissues. This allows for increased uptake of glucose into these insulin-sensitive tissues. Metformin consistently reduces A1C levels by 1.5% to 2%, FPG levels by 60 to 80 mg/dL, and retains the ability to reduce FPG levels when they are very high (>300 mg/dL). It reduces plasma triglycerides and low-density lipoprotein (LDL) cholesterol by 8% to 15% and modestly increases high-density lipoprotein (HDL) cholesterol (2%). It does not induce hypoglycemia when used alone. 

Figure 1.13 Communication to and from the cardiovascular centre in the brain. The cardiovascular centre controls changes in the output from the heart (cardiac output) and the flow of blood through peripheral b ssues and organs. It is the efferent neurones that transfer informab on from the brain to the heart and peripheral vessels. The afferent neurones transfer informab on from the heart and other b ssues, e.g. muscle, to the centre. Informab on transfers from the major arteries, the coronary arteries and peripheral muscles to the brain. There is also informab on transfer within the brain and within the muscle.

D. E. Jones, K. G. Hollingsworth, R. Taylor, A. M. Blamire and J. L. Newton, Abnormalities in pH handling by peripheral muscle and potential regulation by the autonomic nervous system in chronic fatigue sjmdrome. J. Intern. Med., 2010, 267,394-MOl. 

Atherosclerosis can result in ischemia of peripheral muscles just as coronary artery disease causes cardiac ischemia. Pain (claudication) occurs in skeletal muscles, especially in the legs, during exercise and disappears with rest. Although claudication is not immediately life-threatening, peripheral artery disease is associated with increased mortality, can severely limit exercise tolerance, and may be associated with chronic ischemic ulcers and susceptibility to infection. 

The exactly opposite effects of drugs and dreams on pupillary aperture and reflex excitability are important examples of informative differences between the two states. REM sleep is off-line—that is, the brain is dissociated from inputs and outputs—precisely because access of afferent stimuli to the CNS is blocked (e.g., pupillary myosis), as is access of internally generated motor commands to the peripheral muscles (e.g., inhibited deep tendon reflexes). Were this not the case, REM sleep would be waking (or a hybrid state even more like drug psychosis). And if the converse were... 

Fig. 20.10. The muscles of the lower hind limb in cross-section. In this image, anterior is down and medial is left. Abbreviations are as follows MG, medial gastrocnemius LG, lateral gastrocnemius Plant, plantaris PN, plantar nerve Sol, soleus Fib, fibula EDL, extensor digitorum longii TA, tibialis anterior Tib, tibia. The mouse muscles are predominantly fast muscle fibers, but the soleus is valuable for its high percentage of slow fibers. Note, the darker mass on the posterior portion of the leg is a lymph node that provides a convenient landmark when sectioning to establish that reproducible sections are examined in the proximal/distal axis. Also, the peripheral muscles in the section are the hamstrings, which insert along the tibia in the lower leg in the mouse. (Color figure is available online).

Matsumoto, H. Takenami, E. Iwasaki-Kurashige, K. Osada, T. Katsumura, T. Hamaoka, T. 2005. Effects of blackcurrant anthocyanin intake on peripheral muscle eirculation during typing work in humans. Eur. J. Appl. Physiol. 94 36-45. 

Receptor distribution probably explains why ephedrine has no effect on diastolic pressure, and only minimal effect on systolic. p2 Stimulation of vessels in peripheral muscles results in peripheral vasodilation and diastolic runoff, which more than cancels ephedrine s other inotropic effects (29). The absence of any significant effect on blood pressure was firmly established during the late 1970s and early 1980s in dozens of double-blind, placebo-controlled studies performed to compare the effectiveness of ephedrine with that of newly synthesized adrenergic agents (30-60). 

They seem to increase glucose uptake by peripheral muscle cells and reduce gluco-neogenesis and intestinal glucose absorption. Only one, metformin, is available in the United Kingdom. It does not stimulate appetite and therefore is useful in obese patients. 

Normally, visible brain white matter consists of large tracts of many thousands of myelinated nerve fibers—nerve fibers individually covered by a periodically interrupted fatty sheath that makes rapid conduction of electrical impulses over long distances possible. Rapid conduction of nerve activity to peripheral muscles is necessary for effective muscle movements, especially for movements such as walking. 

Cellular studies indicate that the peripheral muscle targets for motoneurons play a variety of roles in shaping the axon morphology of those neurons causing motor axons to diverge away from a fascicle, providing a substrate for axon advancement, and signalling motoneurons to withdraw inappropriate branches. Studies of the molecular basis for these phenomena are in their infancy. 

Two techniques are used predominantly, such as (a) the radioligand binding assays on the brain-tissues and b) the electrically stimulated peripheral muscle preparations. 

Activity C-T. 1 is probably the most effective peripheral muscle relaxant. It is hardly used in current therapy because the corresponding diallylnortoxiferinium chloride (alcuronium chloride, Alloferin ) has a shorter duration of action. The muscle relaxant effect results from a (competitive) expulsion of acetylcholine from the receptors of the motoric endplates with paralysis of the transversely striated musculature (overdoses cause death by asphyxiation). 

Neural Excitation of Muscle. Voluntary contraction of human muscle initiates in the frontal motor cortex of the brain, where impulses from large pyramidal cells travel downward through corticospinal tracts that lead out to peripheral muscles. These impulses from the motor cortex are called action potentials, and each impulse is associated with a single motor neuron. The principle structure of a motor neuron is shown in Fig. 6.IS. The action potential initiates in the cell body, or soma, and travels down a long efferent trunk, called the axon, at a rate of about 80 to 120 m/s. The action potential waveform is the result of a voltage depolarization-repolarization phenomenon across the neuron cell membrane. The membrane ionic potential at rest is distuibed by a surrounding stimulus, and Na ions are allowed to momentarily rush inside. An active transport mechanism, called the Na —K+ pump, quickly returns the transmembrane potential to rest This sequence of events, which lasts about 1 ms, stimulates a succession of nerve impulses or waves that eventually reach muscle... 

In untreated diabetes, the peripheral muscles are, like the liver, depleted of glycogen. In contrast, glycogen has been found in the hearts of diabetics. However, on the basis of histochemical and chemical analyses, researchers concluded that there was no correlation between the amount of glycogen deposited in the heart and the severity of the diabetes. The presence of glycogen in the liver nuclei has been contested by Byrd and Fischer. These authors believe that the vacuolization observed in that cellular organelle results from fluid imbalance rather than from the accumulation of glycogen. 

Although they interfere with the insect s nervous system their mode of action is different to that of organophosphates and carbamates and is novel. It involves inhibition of a-aminobutyric acid (GABA)-mediated inhibitory potentials as well as the excitatory postsynaptic potentials at the neuromuscular junction. This stops GABA-mediated nerves from regulating peripheral muscles. 

Approximately 15% of patients receiving PMV or LTMV have NMD (37,64). NMD can be grouped into disorders involving the central nervous system, such as multiple sclerosis and amyotrophic lateral sclerosis the motor neuron, such as postpolio syndrome and amyotrophic lateral sclerosis the peripheral nerves, such as Guillain-Barre syndrome the neuromuscular junction, such as botulism and myasthenia gravis and the peripheral muscles, such as inflammatory myopathies, myotonic dystrophy type 1, and Duchenne s muscular dystrophy (40). 

Muscle retraining Respiratory muscle training Peripheral muscle training NMES... 

Zanotti E, Felicetti G, Maini M, et al. Peripheral muscle strength training in bed-bound patients with COPD receiving mechanical ventilation. Effect of electrical stimulation. Chest 2003 ... 

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