Mechanical skeletal failure

The ACE gene encodes two isozymes (somatic ACE isozyme and germinal ACE isozyme). ACE is a membrane-bound enzyme on the surface of vascular endothelial cells that also circulates in plasma and shows great individual variability determined by an I/D polymorphism in intron 16 of the ACE gene (ACE-I/D polymorphism). More than 160 ACE polymorphisms have been reported, 34 of which are located in coding regions, and 18 are missense mutations (606). ACE-related polymorphic variants have been associated with hypertension, atherosclerosis, stroke, left ventricular hypertrophy, chronic renal failure in IgA nephropathy, Henoch-Schonlein purpura nephritis, mechanical efficiency of skeletal muscle, intracranial aneurysms, susceptibility to myocardial infarction, diabetic nephropathy, AD, and longevity (12,606,607). 

Cardiomyocytes are known to express HSL [68, 78, 79 see below] and the hormone-responsiveness of myocardial lipolysis suggests that HSL is probably responsible. In addition, the heart can synthesize and secrete apoB-containing lipoproteins [3]. If, as apparently with the liver, endogenous TAG is mobilized for lipoprotein assembly via a lipolytic event the question arises can HSL fulfil this function in the heart or is another lipase involved in a mechanism identical to that in the liver It has been proposed that mobilization of endogenous cardiac TAG for lipoprotein secretion provides the heart with a safety valve to dispose of excess lipid [3] and thus protects against lipotoxicity [65]. Lipoapoptosis observed in the heart leads to the development of heart failure [80, 81]. If, as apparently with skeletal muscle [82], excess TAG accumulation plays a role in insuhn resistance, hpoprotein secretion may enable cardiac muscle insuhn sensitivity in the face of an excessive flux of FA. 

Failure to detect oligosaccharides in the early stages of dextran synthesis and the observation that dextrans attain high molecular weights (Mw 5 X 10°) in the early stages of the synthetic reaction have been cited as evidence that a single-chain mechanism operates during the synthesis of skeletal chains. 

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