In body fluids and tissues

The microbial assay is based on the growth of l ctobacillus casei in the natural (72) or modified form. The lactic acid formed is titrated or, preferably, the turbidity measured photometrically. In a more sensitive assay, l euconostoc mesenteroides is employed as the assay organism (73). It is 50 times more sensitive than T. casei for assaying riboflavin and its analogues (0.1 ng/mL vs 20 ng/mL for T. casei). A very useful method for measuring total riboflavin in body fluids and tissues is based on the riboflavin requirement of the proto2oan cHate Tetrahjmenapyriformis which is sensitive and specific for riboflavin. 

PLC studies in the field of medicine cover the processes of separation, purification, and determination of xenobiotics or endogenous substances present in body fluids and tissues. Such research is carried out with the following aims ... 

Analytical methods for the determination of residues in body fluids and tissues must be submitted only if the a.i. is classified as toxic or highly toxic. The method has to be validated only at the LOQ in general blood 0.05 mgL and tissues 0.1 mgkg (meat or liver, if not investigated under food of animal origin, see Section 4.2.1). 

The specific and sensitive GLC determination of griseofulvin in body fluids and tissues such as skin, sweat, urine and plasma with electron capture detection has been used by several investigators (34,51,52). 

Identification and Determination in Body Fluids and Tissue Griseofulvin has usually been determined in body fluids... 

The recognition of their structure permits the determination of vitamins by the tools of analytical chemistry, but while such methods are widely used in industrial production, the minute quantities in body fluids and tissues limit the purely chemical approach to a few members of this group present in relatively high concentration, e.g., vitamin C (K5). Microchemical methods are in use for the determination of thiamine, riboflavin, and some of the fat-soluble vitamins, based on the most sensitive colorimetric and, in particular, fluorometric techniques. Vitamin D, on the other hand, is determined by animal assay. 

The establishment of quantitative methods for the determination of vitamins in body fluids and tissues by microbiological assay techniques should stimulate the search for the significance of vitamins in disease, not only in nutritional deficiency, but in the much wider field of all metabolic disturbances. Functional vitamin deficiencies are produced by malabsorption, by inhibitors of the vitamin function through products of the body, and particularly through drugs and other toxic substances. Vitamin deficiencies may be relative deficiencies whenever an individual s metabolism is deranged so as to require enhanced quantities of a given vitamin to cure or to counteract certain symptoms as, e.g., in Darier s disease (keratosis follicularis) (P2a). 

Although we can measure the amount of chloroform in the air that you breathe out, and in blood, urine, and body tissues, we have no reliable test to determine how much chloroform you have been exposed to or whether you will experience any harmful health effects. The measurement of chloroform in body fluids and tissues may help to determine if you have come into contact with large amounts of chloroform. However, these tests are useful only a short time after you are exposed to chloroform because it leaves the body quickly. Because it is a breakdown product of other chemicals (chlorinated hydrocarbons), chloroform in your body might also indicate that you have come into contact with those other chemicals. Therefore, small amounts of chloroform in the body may indicate exposure to these other chemicals and may not indicate low chloroform levels in the environment. From blood tests to determine the amount of liver enzymes, we can tell whether the liver has been damaged, but we cannot tell whether the liver damage was caused by chloroform. 

Morgan and Rouge 1984 Toijussen and Andersen 1979). These data do not refer to populations living aroimd the hazardous waste sites that contain elevated levels of nickel. Additional studies which examine nickel levels in body fluids and tissues from persons living near hazardous waste sites that contain elevated levels of nickel would be useful. 

High Performance Liquid Chromatography Determination in Body Fluids and Tissues Miscellaneous Analysis Methods... 

The initial metabolism of heroin involves loss of one acetyl group, forming6-monoacetylmorphine, or 6-MAM. If6-MAM is detected in body fluids and tissues, it can only have come from heroin. When 6-MAM is further metabolized, it loses the second acetyl group and forms morphine. At this point, finding morphine, is not helpful in determining whether the individual had used heroin or morphine, or even codeine, since it also is metabolized to morphine. 

After oral adrninistration, the fluoroquinolones are well absorbed with the bioavailability of 80 to 95 % and distributed widely in body fluids and tissues. Depending upon the newer compound, the different dose regimen have been adopted. The fluoroquinolones are excreted mainly by tubular secretion and by glomerular filtration. 

Disposition According to Microme-dex, data on the metabohsm of interferon beta are lacking. However, this compound is similar to interferon alfa, which is rapidly inactivated in body fluids and tissue. 

Trimethoprim is usually given orally, alone, or in combination with sulfamethoxazole, which has a similar half-life. Trimethoprim-sulfamethoxazole can also be given intravenously. Trimethoprim is well absorbed from the gut and distributed widely in body fluids and tissues, including cerebrospinal fluid. Because trimethoprim is more lipid-soluble than sulfamethoxazole, it has a larger volume of distribution than the latter drug. 

A large elevation of Hey in body fluids and tissues is found in several genetic enzyme deficiencies, the homocystinurias. These include cystathionine /3-synlhase deficiency [9], the remethylation defects due to deficiency of MTHF reductase [10], methionine synthase and methionine synthase reductase deficiencies, as well as defects of intracellular cobalamin metabolism [11], namely the cblF, cblC and cblD defects. It is noteworthy that low levels of total Hey (tHcy) have been described in sulphite oxidase deficiency [12]. 

Several alternative methods for the determination of sialic acid in body fluids and tissues have been described. Most of these methods make use of the classic periodate-TBA assay in combination with purification using HPLC [13]. Another method makes use of fluorometric HPLC of sialic acids after derivatization with a fluorogenic compound [9]. The most promising new method for the determination of free sialic acid in urine (and probably also other body fluids and tissues) is the HPLC-tandem mass spectrometry method [19]. This method is rapid, accurate, and sensitive, and is more robust than earlier methods. The only disadvantage is the expensive equipment that is required, which makes it only economical for specialized metabolic laboratories. Since this equipment is used for many different metabolic assays, the investment is certainly warranted, and nowadays almost essential for any metabolic laboratory. 

In the past decade, eight inherited disorders have been linked to specific enzyme defects in the isoprenoid/cholesterol biosynthetic pathway after the finding of abnormally increased levels of intermediate metabolites in tissues and/or body fluids of patients (Table 5.1.1) [7, 9, 10]. Two of these disorders are due to a defect of the enzyme mevalonate kinase, and in principle affect the synthesis of all isoprenoids (Fig. 5.1.1) [5]. The hallmark of these two disorders is the accumulation of mevalonic acid in body fluids and tissues, which can be detected by organic acid analysis, or preferably, by stable-isotope dilution gas chromatography (GC)-mass spectrometry (GC-MS) [2]. Confirmative diagnostic possibilities include direct measurement of mevalonate kinase activities in white blood cells or primary skin fibroblasts [3] from patients, and/or molecular analysis of the MVK gene [8]. 

Z Deyl, J Hyanek, M Horakova. Review profiling of amino acids in body fluids and tissues by means of liquid chromatography. J Chromatogr 379 177-250, 1986. 

The amount consumed could be considerably higher in the Mediterranean diet, which is rich in olive oil, citrus fruits, and greens. These quantities could provide pharmacologically significant concentrations in body fluids and tissues. Nevertheless, flavonoid dietary intake far exceeds that of vitamin E, a monophenolic antioxidant, and that of P-carotene on a milligram per day basis. From this we can conclude that... 

---