Muscles wasting

Insulin is a powerful anabolic hormone but it is unlikely that insulin deficiency causes skeletal muscle atrophy by direct action on muscle fibers (as opposed to neurogenic atrophy) except in chronic untreated cases. There is however a close parallel between the catabolic states induced by glucocorticoid excess and by insulin deficiency. Moreover, impaired insulin action is implicated in other endocrine myopathies as a contributory cause of muscle wasting. Both acromegaly and thyrotoxicosis are associated with insulin resistance due to a postreceptor defect, and secondary hyperparathyroidism due to hypophosphatemia also gives rise to insulin insensitivity. 

Motor neuron disease AIDS Subacute Motor dysfunction, muscle wasting with upper motor neuron signs bulbar dysfunction Possible immune mediated... 

Pathogen-suppressing oligosaccharides in human milk were quantitated using capillary Electrophoresis by MEKC with detection by absorption at 205 nm.90 A 24 kDa glycoprotein associated with muscle-wasting cachexia... 

Approximately 80% of patients with a GFR less than 20 to 30 mL/minute develop metabolic acidosis.38 Metabolic acidosis can increase protein catabolism and decrease albumin synthesis, which promote muscle wasting, and alter bone metabolism. Other consequences associated with metabolic acidosis in CKD include worsening cardiac disease, impaired glucose tolerance, altered growth hormone and thyroid function, and inflammation.38... 

Albumin and amino acid loss Muscle wasting Increased adipose tissue Fibrin formation in dialysate... 

Poly(L-lysine) has also been suggested as a carrier for pepstatin, a specific inhibitor of the lysosomal proteinase cathepsin D, responsible for causing muscle-wasting diseases, such as muscular dystrophy [257],... 

Musculoskeletal Effects. Muscle wasting and atrophy have been reported in humans occupationally exposed to n-hexane (Yamamura 1969). These effects occurred in individuals with severe neurotoxicity. 

Musculoskeletal Effects. Muscle wasting and atrophy have been reported in humans occupationally exposed to -hexane (Yamamura 1969). These effects occurred in individuals with severe neurotoxicity. Muscle atrophy is a common finding after intermediate-duration inhalation exposure to n-hcxanc in experimental animals. This atrophy is secondary to i -hexane-induccd neurotoxicity which results in... 

The muscle wasting associated with critical illness cannot be prevented/reversed by provision of calories and nitrogen alone. The need to overcome this catabolic drive has led to a number of trials of supplementary feeding regimens with, for example, either glutamine or growth factors. Whilst both have shown some benefit, there is no unequivocal evidence to support their use and... 

Adequate nutrition improves wound healing, decreases the risk of infection, reduces muscle wasting and maintains muscle function after trauma. The following extract emphasises this ... 

Symptoms of hepatic failure include accumulation of fluid in the abdomen and lower body leading to ascites, weight loss, muscle wasting, jaundice and anaemia. 

Kemp, G., Crowe, A.V., Anijeet, H.K.I., Gong, O.Y., Bimson, W.E., Frostick, S.P., Bone, J.M., Bell, G.M. and Roberts, L.N. (2004) Abnormal mitochondrial function and muscle wasting, but normal contractile efficiency, in haemodialysed patients studied non-invasively, in vivo. Nephrology, Dialysis, Transplantation, 19, 1520-1527. 

Symptoms include arrested growth, extreme muscle wasting (emaciation), weakness, and anemia all these symptoms contribute to frequent infections. 

These conditions may produce cachexia, in which increased degradation of proteins leads to muscle wasting. 

ALS, as already discussed, is a condition characterized by degeneration of the spinal and brainstem motor neurons, resulting in muscle wasting and eventually death. It affects approximately 70000 people worldwide. Several neurotrophic factors known to positively influence motor neurons in vitro and/or in vivo (Table 7.11) have or are being assessed in clinical trials as therapeutic agents for ALS. 

Long-term therapy may cause hypocalcemia, hypokalemia, muscle wasting in arms and legs, osteoporosis, spontaneous fractures, amenorrhea, cataracts, glaucoma,... 

Mechanism of Action An immunomodulator whose exact mechanism is unknown. Has sedative, anti-inflammatory, and immunosuppressive activity, which may be due to selective inhibition of the production of tumor necrosis factor-alpha. Therapeutic Effect Improves muscle wasting in HIV patients reduces local and systemic effects of leprosy. 

Accuracy reduced in muscle wasting diseases (e.g., neuromuscular disease) and amputees... 

The decrease of renal function with age is independent of the decrease in creatinine production. Because of the difficulty of obtaining complete urine collections, creatinine clearance calculated in this way is at least as reliable as estimates based on urine collections. Fat-free mass (equation [14]) should be used for obese patients, and correction should be made for muscle wasting in severely ill patients. 

Muscle Wasting in Starvation One consequence of starvation is a reduction in muscle mass. What happens to the muscle proteins ... 

Marasmus Marasmus occurs when calorie deprivation is rela tively greater than the reduction in protein. Marasmus usually occurs in children younger than one year of age when the mother s breast milk is supplemented with thin watery gruels of native cereals, which are usually deficient in protein and calories. Typical symptoms include arrested growth, extreme muscle wast ing (emaciation), weakness, and anemia. Victims of marasmus do not show the edema or changes in plasma proteins observed in kwashiorkor. 

Although the net effect of HIV infection is immunodeficiency, the infection generally results in the increased activation of the immune response but the overall impact of this immune hyperactivity is negative. The activated CD4+ cells play a pivotal role in the replication of the virus this activation of CD4+ cells enhances the secretion of various cytokines, some of which contribute to muscle wasting. A superactive humoral response against HIV impairs the body s ability to mount antibody response against other pathogens, and the activation of immune response... 

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