In various tissues

Glycosydation AChE and BChE carry 3 and 9, respectively, N-glycosylation consensus sequences attaching carbohydrate residues to the core protein via asparagines. Different molecular forms of the enzymes in various tissues, show different number and composition of carbohydrate residues. N-glycosylation at all sites was shown to be important for effective biosynthesis, secretion and clearance of ChEs from the circulation. Altered patterns of AChE glycosylation have been observed in the brain and cerebrospinal fluid of Alzheimer s disease (AD) patients, with potential diagnostic value. 

CYP27A1 catalyzes the side chain oxidation (27-hydroxylation) in bile acid biosynthesis. Because bile acid synthesis is the only elimination pathway for cholesterol, mutations in the CYP27A1 gene lead to abnormal deposition of cholesterol and cholestanol in various tissues. This sterol storage disorder is known as cerebrotendinous xanthomatosis. CYP27B1 is the 1-alpha hydroxylase of vitamin D3 that converts it to the active vitamin form. The function of CYP27C1 is not yet known. 

Histamine is a substance present in various tissues of die body, such as die heart, lungs, gastric mucosa, and skin (Pig. 36-1). The highest concentration of histamine is found in die basophil (a type of white blood cell) and mast cells diat are found near capillaries. Histamine is produced in response to injury. It acts on areas such as die vascular system and smooth muscle, producing dilatation of arterioles and an increased permeability of capillaries and venules. Dilatation of die arterioles results in localized redness. An increase in die permeability of... 

In-vitro models can provide preliminary insights into some pharmacodynamic aspects. For example, cultured Caco 2 cell lines (derived from a human colorectal carcinoma) may be used to simulate intestinal absorption behaviour, while cultured hepatic cell lines are available for metabolic studies. However, a comprehensive understanding of the pharmacokinetic effects vfill require the use of in-vivo animal studies, where the drug levels in various tissues can be measured after different dosages and time intervals. Radioactively labelled drugs (carbon-14) may be used to facilitate detection. Animal model studies of human biopharmaceutical products may be compromised by immune responses that would not be expected when actually treating human subjects. 

No studies were located regarding distribution in humans or animals after inhalation exposure to methyl parathion. Although cases of inhalation exposure have been reported, there were no data that provided detailed information on the distribution of methyl parathion residues in various tissues. 

Studies in animals and autopsy findings of endosulfan and metabolites in various tissues in humans suggest that absorbed endosulfan is most readily distributed to adipose and brain tissue, but that the liver and kidney may be longer-term repositories of endosulfan and its metabolites. Endosulfan residues were found in fat of hospitalized Spanish children (Olea et al. 1999), but no studies were located regarding known or suspected differences between children and adults with respect to endosulfan distribution. 

Table II. Activity Expressed as Percent of Dose per Gram (%/gram) in Various Tissues of Rats 3, 7, and 21 Days Following a Single Oral Dose of TCDD- C ...

Intravenous lipid emulsion particles are hydrolyzed in the bloodstream by the enzyme lipoprotein lipase to release free fatty acids and glycerol. Free fatty acids then are be taken up into adipose tissue for storage (triglycerides), oxidized to energy in various tissues (e.g., skeletal muscle), or recycled in the liver to make lipoproteins. 

Fig. 7 Thiopental concentrations in various tissues following 25-mg/kg IV bolus doses. Solid symbols indicate data in dogs the open circles are from data in humans. Lines correspond to predicted values in various tissues using a perfusion model containing compartments corresponding to the blood, viscera, lean, and adipose tissues. (From Ref. 26.)...

Table 4 Distribution and Characteristics of Endothelium in Various Tissues... 

Absorbed lead is distributed in various tissue compartments. Several models of lead pharmacokinetics have been proposed to characterize such parameters as intercompartmental lead exchange rates, retention of lead in various pools, and relative rates of distribution among the tissue groups. See Section 2.3.5 for a discussion of the classical compartmental models and physiologically based pharmacokinetic models (PBPK) developed for lead risk assessments. 

Unidirectional, first-order transfer rates (day1) between compartments were developed for 6 age groups, and intermediate age-specific values are obtained by linear interpolation. The range of age-specific transfer rate values are given in Table 2-8. The total transfer rate from diffusible plasma to all destinations combined is assumed to be 2,000 day"1, based on isotope tracer studies in humans receiving lead via injection or inhalation. Values for transfer rates in various tissues and tissue compartments are based on measured deposition fractions, or instantaneous fractional outflows of lead between tissue compartments (Leggett 1993). 

Protein Rat Body lead retention Low dietary protein either reduces or does not affect retention in various tissues Quarterman et al. 1978... 

Ujihara, M., et al. (1988). Prostaglandin D2 formation and characterization of its synthetases in various tissues of adult rats. Arch. Biochem. Biophys. 260,... 

Metallic nanoparticles have been synthesized in vivo using plants. Intracellular synthesis of gold nanopartides was demonstrated using the sweet desert willow (Chilopsis linearis) plant [95]. The average size of Au nanopartides formed in various tissues was dependent on the concentration of Au in the respective tissues. Haver-kamp et al. [96] synthesized a gold-silver-copper alloy in vivo using the Brasskajuncea plant. 

The carbohydrate metabolic routes in various tissues of the organism discussed above differ in intensity, which is defined by metabolic features specific of each tissue and organ. However, from the standpoint of activity of the whole organism, certain specializations of the carbohydrate metabolic routes in individual tissues are profitably complementary. For example, strenuous muscular exertion requires energy which is initially supplied by the breakdown of glycogen to lactic acid. The latter compound is excreted into the blood to be supplied... 

Wu, X., et al. Cloning and characterization of glucose transporter 11, a novel sugar transporter that is alternatively spliced in various tissues. Mol. Genet. Metab. 2002, 76, 37—45. 

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