Injection labelling

Further biosynthetic experiments were performed with the aim to clarify metabolic relationships between polygodial and the esters, as well as to ascertain whether or not polygodial was the precursor of the esters. Two series of experiments [86] were performed injecting labelled [2-14C] mevalonic acid into nine (4.5 pCi) and fourteen (7 pCi) animals, which were sacrificed at various times from 3 to 77 h. The two experiments, performed during the months of March and April, 1984, led to apparently conflicting but not contradictory results. In fact, in the first series of experiments the major specific recovered radioactivity was always associated with polygodial (30). On the other hand, the... 

The Council supports the recommendations of the USP-FDA Advisory Panel on Simplification of Injection Labeling. Furthermore, the Council encourages USP/FDA to consider expansion of the concepts of simplification to apply to package inserts and... 

Flow Injection Label-free MS Assay Screening of Natural Extracts... 

Step 2 Inject label onto antibody support... 

In man, the volume of distribution of the cyclic nucleotides exceeds the extracellular fluid space [125], and only about 15% of injected labelled cyclic AMP is excreted by the kidney. Extrarenal cyclic nucleotide clearance probably involves hepatic metabolism and/or biliary excretion, but cyclic AMP is also destroyed by renal phosphodiesterase. The isolated perfused rat kidney rapidly removes cyclic AMP from the perfusion medium [126]. 

When lipophorin, containing labeled DG, was injected into M. sexta larvae, the DG disappeared from the hemolymph with a half-life of about 50 min, and after 4 hr about 60% of the injected label was found in fat body as TG (Tsuchida and Wells, 1988). When DG-labeled lipophorin was incubated in vitro with fat body, more than 95% of the label was taken up by fat body within 4 hr the half-life of labeled DG in the incubation medium was about 60 min, a value comparable to the in vivo measurement. During the incubation, after 95% of the DG had entered the fat body, there was no detectable loss of lipophorin apolipoproteins from the incubation medium. However, the density of the lipophorin in the incubation medium increased substantially, consistent with the loss of DG. These results are compatible with the hypothesis that lipophorin functions as a reusable, noninternalized shuttle. 

Pathways PI3K clinical setting utilizes NIS activity by injecting labeled I2 that... 

The plasma clearance of an injected labeled TH can be used to calculate both the exchange of TH between plasma and major tissue compartments and the irreversible plasma clearance of TH which can be used to determine the TH DR67. TH plasma... 

Studies with ureido citrulline- C showed that the child could convert about 30% of the injected labeled citrulline to urea in a 24-hour period. 

Xanthine oxidase, which is capable of catalyzing the conversion of hypoxanthine and xanthine to uric acid, was first detected in 1882 by Horbaczewski (Hll), who noted that extracts of various tissues could catalyze the conversion of xanthine to uric acid. A similar enzyme was detected in milk (M15). These enzymes contain a flavin-adenine dinucleotide prosthetic group (C9). As a result of the essential nature of the flavin-adenine dinucleotide portion of the enzjmie, a striking parallelism was seen between the riboflavin content of the diet and the xanthine oxidase concentration in tissues of growing rats (DIO). The enzyme contains molybdenum. That the molybdenum is contained in a functionally important component has been demonstrated by several workers (G13, T5). Totter and his associates injected labeled molybdate into a cow, and then isolated the enzyme from the milk to show that the proportion between the molybdenum and flavin remained constant at a value of 0.5. Corran et al. (C9) postulated that the xanthine oxidase of milk is identical with the xanthine oxidase of liver, but the protein portions of the enzyme appear to differ. 

Large doses of iodate (1.4—15 mg iodine per kilogram) blocked thyroidal uptake of injected labeled iodide in rats, again suggesting that iodine from iodate is available to the thyroid (Pahuja et al., 1993 Wyngaarden et al., 1952). When added to animal feed, iodate increases the iodine content of eggs and milk (Anke et al., 1998). 

From the resulting residence-time function [F(t) from displacement labeling or w(t) from injection labeling], the mean residence time r can be calculated (Equation 2.2-24). 

Furman et al (1964) have reported studies on the metabolism of the HDL protein, labeled with P , in hyperlipemic subjects. In two patients with fat-induced familial hyperchylomicronemia, the plasma half-time values of the labeled product—1.7 and 1.9 days—were about 50% less than the normal values reported by Scanu and Hughes (1962) and Furman et al (1964). In carbohydrate-induced hyperglyceridemia where VLDL predominates, the half-time values of the radioiodinated protein were intermediate between normolipemic subjects and those with fat-induced hyperlipidemia. An association between the injected labeled... 

In studying the mode of action of D-T4, Rabinovitz [186] found that in euthyroid patients on the drug intravenously injected labeled cholesterol was removed from the serum 2 to 3 times faster than before treatment. It appears, therefore, that D-T4 acts as a h5 ocholesterolemic agent by increasing the rate of oxidative ehmination of cholesterol. 

Secondly, the injected labelled antibodies should not interfere with cellular function, which could significantly change the distribution of the antibodies antigens in the living cells. 

The initial desaturation and incorporation of the injected labeled stearic acid takes place very rapidly after the assimilation of the precursor acid from the blood into the liver cells, indicating that enz3rmatic fatty acid activation to acyl CoA proceeds at a very high rate. On the other hand, because of the very rapid turnover of plasma-free fatty acids, the supply of labeled precursor acid to the ester pools is rapidly exhausted. 

Apparently, in less than five minutes the injected labeled stearic acid is already desaturated and incorporated into lipids (Elovson, 1965). 

The processes reponsible of the different levels of polyenoic fatty acids in brain phosphoglycerides, and their possible differential roles in the various lipid classes are largely unknown. The selectively high levels of arachidonic acid in IPG, in the light of the special metabolic properties of this phospholipid in stimulated tissues, appear of possible significance. IPG has been shown to incorporate very actively intracerebrally injected labelled arachidonic acid (Yau Sun, 1974). The incorporation of the radioactivity in all lipid classes was constant by 40 minutes after the injection. 

No hypothesis yet proposed is in accord with all the observations which have been reported. To take the case of globin synthesis, Muir et injected labeled glycine and valine into rats and determined the specific activities of the terminal and nonterminal valine in the circulating hemoglobin 12, 24, and 72 hours and 1 and 2 weeks after the injection. The valine in the two sets of loci had the same specific activity. Also the ratio of incorporated glycine to valine remained the same throughout the experimental period. The authors conclusion was that... 

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