Polygen

California), Sibyl (Tripos, Missouri), ChemX (Chemical Design, UK), BioGraf (Molecular Simulations, California), Charmm/Quanta (Polygen Corp., Massachusetts), PC Model (Serena Software, Indiana), ChemLab (ChemLab Inc., Illinois), and a large number of personal computer-based packages. 

Leptin is a cytokine produced and secreted by adipose tissue in proportion to the body fat content [3]. Mice and humans lacking leptin or its receptor develop a severe hyperphagia and a dramatic degree of obesity which is considerably more pronounced than that of the NDRKO mouse. Thus, leptin is the key adiposity signal in rodents and humans. Leptin secretion appears to reflect the metabolic status of the adipocyte rather than the sheer size of triglyceride deposits, and leptin levels may transiently be dissociated from total body fat. Nonetheless, over the course of a day with unrestricted food supply, plasma leptin levels reliably reflect the amount of total body fat. Local administration of leptin into the brain results in reduced food intake. The vast majority of patients with obesity have elevated serum levels of leptin. Thus, it is believed that the polygenic obesity is due to leptin resistance rather than to inadequate leptin secretion, or to a reduced blood/brain transport of the cytokine. 

Leptin has been shown to markedly reduce appetite and weight in the extremely rare individuals who lack leptin. In contrast, in the first clinical study of patients with polygenic obesity and elevated leptin levels, weight loss was variable and relatively small. This disappointing result may be explained by the leptin resistance consistently observed in obese humans and rodents. However, it cannot be excluded that a small... 

Chemogenic Volcanogenic Polygenic <10 >50 <10 Iron-manganese nodules, glauconite, phosphorite, nodules, phUlipsite, palagonite, celestobarite, and evaporites Pyroclastic material 38 Red clay... 

There is a polygenic inheritance pattern which may account for disease susceptibility and expression.7 Family... 

Weeks D, Lathrop G. Polygenic disease methods for mapping complex disease traits. Trends Genet 1995 11 513-519. 

The development of autoimmune disease depends on a combination of genetic and environmental factors (Figure 24.1).3-5-28 Most autoimmune diseases are thought to be polygenic, involving more than one gene, and depend on the accretion of a number of genetic traits.5-10... 

Kotlikoff These are all very polygenic responses. Have you looked carefully at something like K+ depolarization in all three of your backgrounds ... 

Polygenic mutations, in which the condition results from the interaction of several genes and may include an environmental component. 

There is also the need to understand the relationship between gene structural defects and protein functions as it may be reflected in disease penetrance, or polygenic disorders. 

The term multifactorial refers to the fact that most common diseases are caused by multiple factors their expression is influenced simultaneously by multiple genes (i.e., a polygenic component) and by environmental factors. Because multiple factors are involved in the causation of these traits, they tend to foUow a normal ( bell-shaped ) distribution. An example would be the distribution of diastolic blood pressures in a population (Fig II-5-1). Other traits that have multiple genetic and environmental components include height, we t, and IQ. 

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