Metabolic characteristics

In general, most of the metabolizing enzyme systems would appear to develop from the middle of gestation until a few months after birth. Enzyme activities related to oxidation/hydroxylation and reduction are developed early after birth and reach adult levels at approximately six months of age. Oxidative demethylation, on the other hand, is not expressed until several months after birth, and the adult capacity will not be reached until one to two years after birth. 

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Kim et al, 2000). The specific metabolic activities depend on the composition of the resident assemblages and dietary inputs. Collectively, these findings highlight how changes in the populations and metabolic characteristics of the resident bacteria can affect the GIT and the host. 

Gieg LM, A Otter, PM Fedorak (1996) Carbazole degradation by Pseudomonas sp. LD2 metabolic characteristics and identification of some metabolites. Environ Sci Technol 30 575-585. 

Cohen N, Wrenn ME. 1973. Metabolic characteristics of241 Am in the adult baboon. Radiat Res 55 129-143. 

Waagepetersen, H. S., Sonnewald, U., Larsson, O. M. etal. Multiple compartments with different metabolic characteristics are involved in biosynthesis of intracellular and released glutamine and citrate in astrocytes. Glia 35 246-252, 2001. 

Phosphorus MRS studies of depressed subjects strongly indicate that this disorder arises from altered brain energy metabolism 944 Hydrogen MRS has revealed unique and consistent metabolic characteristics in the brains of patients with probable AD 944 Hydrogen and phosphorus MRS have proven to be useful tools in the characterization of several epilepsies 944... 

Other than the sweeteners discussed so far thaumatin is a polypeptide consisting of amino acids commonly found in food proteins. It is quickly and completely digested like proteins and did, after demonstration of its metabolic characteristics, only require a rather limited set of safety data. In contrast to the other intense sweeteners the ADI of thaumatin is not specified , as for substances of similar composition.27 It is approved in many countries but, owing to its flavour enhancing properties, is often used as a flavour enhancer rather than a sweetener. 

Fruchard (F16) also observed, performing affinity chromatography, two distinct classes of particles that contain apo(a) one with and one without apoE, exhibiting different structural, functional, and metabolic characteristics. 

Functional differences are reflected by metabolic characteristics of the skeletal musculature in particular where specialized cell types have evolved to permit activity of different intensity and duration to accommodate the wide range of actions for which skeletal muscle is responsible. 

Florea BI, Cassara ML, Junginger HE, Borchard G (2003) Drug transport and metabolism characteristics of the human airway epithelial cell line Calu-3. J Control Release 87(1-3) 131-138. 

Archaea Unicellular microorganisms that are structurally similar to prokaryotes but include some metabolic characteristics of eukaryotes. The archaea are genetically distinct from the other two domains. Most extremoptules are members of the archaea. 

Xia XY, Peng RX, Yu JP, Wang H, Wang J (2002) In vitro metabolic characteristics of cytochrome P-450 2A6 in Chinese liver microsomes. Acta Pharmacol Sin 23(5) 471-476 Zevin S, Benowitz NL (1999) Drug interactions with tobacco smoking. An update. Clin Pharma-cokinet 36(6) 425 38... 

Table 21.1 Metabolic characteristics of normal proliferating cells and tumour cells...

There are several natural milestones during drug development, and although there are differences between companies, both in the number and in the names of the milestones, these differences are quite small. The first milestone is the selection of a compound in the drug discovery phase for development. In the past this decision was exclusively based on the pharmacology (potency, selectivity) of the compound. Since there is now greater awareness that compounds with attractive pharmacological properties may fail later because of poor solubility or extensive metabolism, the physical chemistry, preliminary PK and metabolism characteristics of the... 

These properties dictate the therapeutic, toxic, and metabolic characteristics of the overall drug molecule. These properties also completely control the ability of the drug to withstand the arduous journey from the point of administration to the receptor site buried deep within the body. These physical properties of drug molecules may be categorized into the following major groupings ... 

Both Pu and Th will probably enter the skeleton and other internal tissues predominantly from inhalation. This statement is based on the fact that in the field, Pu and Th demonstrate similar transfers from soil to small mammals and laboratory studies demonstrate similar metabolic characteristics (1,3,23). Soil chemical behavior is also similar (20). As demonstrated in Table I, natural Th in human bone originates largely from inhalation, even assuming that adsorption from the diet is 0.1%. Another strong agrument for the importance of inhalation is found in tissue distributions of Th-232 and Th-230 in humans. Table V summarizes work by Wrenn, et al. (53) which shows that lungs of non-occupationally exposed individuals contains burdens of Th isotopes comparable to the skeleton. Thorium-228 distributions are different from Th-230,... 

When two signals have opposite effects on a metabolic characteristic such as the concentration of a second messenger X, or the membrane potential Vm, the regulatory outcome results from the integrated input from both receptors. 

Other large animals, such as the elephant and rhinoceros, have similar metabolic characteristics, as do diving mammals such as whales and seals. Dinosaurs and other huge, now-extinct animals probably had to depend on lactic acid fermentation to supply energy for muscular activity, followed by very long recovery periods during which they were vulnerable to attack by smaller predators better able to use oxygen and thus better adapted to continuous, sustained muscular activity. 

As stated earlier, the annual cycles of species and populations divide into periods. The overall description would be the syndrome of the population, while individual metabolic characteristics would be symptoms , borrowing terms from the medical profession. Each period manifests a specific set of metabolic features which support the normal course of vital processes in the population, and the population would enter the next period of the cycle only if the preceding step had been completed. If it had not, the situation would lead to that mass mortality which is so common in nature. The change in metabolism is triggered with the help of the endocrine system, as will be described in the next section. 

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