Metabolism metabolic variations

Few submitted to metabolism variations, in particular to hepatic metabolism Submitted to metabolism variations, in particular via cytochroms... 

For Further Reading J. J. R. Frausto da Silva and R. J. P. Williams, The Biological Chemistry of the Elements The Inorganic Chemistry of Life (Oxford Oxford University Press, 1991). M. F.. Wastney, W. A. House, R. M. Barnes, and K. N. S. Subramanian, "Kinetics of zinc metabolism variation with diet, genetics and disease, Journal of Nutrition, vol. 130, 2000, pp. 1355S-1359S. 

Briggs D, Calder I, Woods R, Tange J The influence of metabolic variation on analgesic nephrotoxicity. Experiments with the Gunn rat. Pathology 14 349, 1982... 

Basis for differences in carbon tetrachloride effects on periportal and pericentral hepatocytes enzymic and metabolic variations. 

PB-PK modelling allows further refinement of the dose-response evaluation by partitioning the relationship into pharmacokinetic (exposure vs. tissues dose) and pharmacodynamic (tissue dose vs. toxic response) components. This allows the uncertainties associated with each component to be assessed separately and adds accuracy to the overall animal to man extrapolation. Future developments of PB-PK modelling may allow specific sub-populations such as the newborn or individuals with metabolic variations to be taken into account. However, before this can be done there will need to be considerable growth in the amounts of physiological, pharmacokinetic and pharmacodynamic information available. 

The food supply is strongly influenced by the temperature of the water where the fish live. For this reason, the amplitude of metabolic variations during the annual cycle of a given fish is specific for each climatic zone, whether tropical, temperate-warm, temperate-boreal or polar. The seasonal variations in metabolism (e.g. lipid dynamics) display the greatest range in the... 

In fish which require cold water (sprat and whiting), the annual rhythms are not nearly so well defined. Their preferred temperature zone is in deep water, where the temperature is relatively stable throughout the year. The temperature of the regions of the Black Sea inhabited by warm-water fish may vary by as much as 10-15° over the year, but the habitat of cold-water fish varies by only 3-5°. The latter fish have not only a smaller metabolic variation throughout the year, but also a higher consumption of food in winter (sprats consume 7.3% of their body weight daily at that time) than that of the species requiring warm water. 

The plans for effective synthesis therefore aimed at common intermediates suitable for the synthesis of the natural prostanoids in high yield and for the synthesis of desirable analogues with variations in the molecule around those areas where metabolic variations occur. 

Although considerable progress has been made in the metabolic profile approach, a number of problems remain to be overcome. Many of these centre around the fluctuations in component composition, not from metabolic disorders, but brought about by other influences. These are principally due to diet and the metabolic variations in individuals in relation to activity. Drugs can also affect the excretion levels of compounds, in addition to the production of their own metabolites. These factors all make quantitative data difficult to obtain and evaluate. Careful statistical analysis of the results are necessary and a population of 500 subjects, grouped in age and sex, has been studied with a view to obtaining a suitable data base for urinary organic acids [370]. 

Agarwal, D.P. Goedde, H.W. Medicohiological and genetic studies on alcoholism. Role of metabolic variation and ethnicity on drinking habits, alcohol abuse and alcohol-related mortality. Chn. Invest. 1992 70 465-477... 

In vivo studies. - Many natural compounds and therapeutic drugs form glycosides during transport through the gastrointestinal tract. Mortenson et al have used directly coupled LC- H NMR to various acylated isomers of the glucuronide of S-naproxen in human urine samples. This technique has also been used to study the metabolic variation in rats to identify metabolic populations in urine. 

Gavaghan, C.L. Nicholson, J.K. Connor, S.C. Wilson, I.D. Wright, B. Holmes, E. HPLC-NMR Spectroscopic and Chemometric Studies on Metabolic Variation in Sprague Dawley Rats, Anal. Biochem. 291 (2), 245-252 (2001). 

Derosa G, Franzetti I, Gadaleta G, Ciccarelli L, Fogari R. Metabolic variations with oral antidiabetic drugs in patients with Type 2 diabetes comparison between glimepiride and metformin. Diabetes Nutr Metab 2004 17(3) 143-150. 

Isoflurane is more resistant to biotransformation in man than are other volatile halogenated anaesthetics [201,241,245] although there can be metabolic variations in different animal species [245], An average recovery of95 percent has been obtained in exhaled air, while post-operative urinary excretion of ionic and bound organic fluoride accounted for less than 0.2 per cent of the total fluorine dose [201]. In a separate study of 9 surgical patients, serum inorganic fluoride levels were 4.4 0.4 umol dm 6 h after anaesthesia [241 ]. 

How the MHC confers distinctive odors is not known. The odorants need not be structural derivatives of MHC products, although they could be. MHC genes may be involved in normal metabolic variation which in turn results in different patterns or profiles of odorous materials in the urines of animals of differing H-2 types (see Boyse et al., 1983). 

The observation that the urine odor of animals is discriminably different from urine odor of a 50 50 mixture of individuals of the respective inbred strains (Yamazaki et al., 1984) is consistent with this view. This metabolic variation hypothesis of H-2 odor determination suggests that several tissues, rather than one, contribute to the H-2 odor phenotype. Except for the intact mouse and urine, no highly potent source of H-2 odors has been identified, probably because the odorants, whatever their source, are concentrated in secretions and excretions. 

A cross-validated score plot of PLS-DA model (Q2 [cum] 0.803, R2Y [cum] 0.935) is represented in Figure 8.6. It was built to confirm the metabolic variations... 

Wastney, M., House, W., Barnes, R., and Subramanian, K. (2000) Kinetics of zinc metabolism variation with diet, genetics and disease. J. Nutr., 130, 1355S-1359S. 

Special isotope ratio mass spectrometers are needed to measure the small variations, which are too small to be read off from a spectrum obtained on a routine mass spectrometer. Ratios of isotopes measured very accurately (usually as 0/00, i.e., as parts per 1000 [mil] rather than parts per 100 [percent]) give information on, for example, reaction mechanisms, dating of historic samples, or testing for drugs in metabolic systems. Such uses are illustrated in the main text. 

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