Tissues and Biological Fluids

Standard curves performed under our defined radioimmunoassay conditions ([ H]PbTx-3 = 1 nM, antiserum dilution = 1 2000, assay volume = 1 ml) demonstrated the ability of this antiserum to bind equally to PbTx-2 and PbTx-3, suggesting specificity for the cyclic polyether backbone region of the molecule (Figure 8). The linear portion of the curve indicated a lower detection limit of 0.2-0.5 ng in saline buffer under these conditions. Evaluation of this assay for use with biological fluids and tissue extracts is underway. 

The availability of Compound 118 for wide scale experimentation in the field of agricultural, household, and public health uses makes necessary a method for determining minute amounts such as would be present in spray or dust residues on plants and in biological fluids and tissues. 

Kohen R, Vellaichamy E, Hrbac J, Gati I and Tirosh O. 2000. Quantification of the overall reactive oxygen species scavenging capacity of biological fluids and tissues. Free Radic Biol Med 28(6) 871—879. 

Determination in Biological Fluids and Tissues All the advances in pharmacokinetics and drug metabolism described in Sections 7 and 8 would not have been possible without the availability of the proper analytical methods. The following is a tabulation of publications in this field, most of which have already been discussed in Section 5. It should be mentioned that a few publications talk about aspirin blood levels, but really mean salicylate levels. The following tabulation covers only those papers where aspirin was differentiated from other salicylates by chromatography or other means. It seems that the "workhorse" for serum salicylate levels is still the colorimetric (ferric-nitrate) method of Brodie, Udenfriend and Coburn153 published in 1944, or modifications thereof. Simplified versions (cf. 206) may lead to erroneous results under certain conditions.207 The method is also applicable for urinary metabolites after proper hydrolysis (cf. 208). For other methods restricted to salicylic acid, see Section 5.61. 

The chemistry, metabolism, and clinical importance of folic acid have been the subject of many excellent reviews (A7, Gil, H14, H20, Rl). Folic acid deficiency leads to a macrocytic anemia and leucopenia. These symptoms are due to inadequate synthesis of nucleic acid. The synthesis of purine bases and of thymine, required for nucleic acid synthesis, is impaired in folic acid deficiency. Detection of folic acid activity in biologic fluids and tissues is of the utmost importance it distinguishes between the various anemias, e.g., those due to vitamin Bi2 or folic acid deficiency. Because morphology of the abnormal red cell does not help in diagnosing vitamin deficiency, one must rely on assay methods for differential diagnosis. Treatment of pernicious anemia with folic acid has led to subacute combined degeneration of the spinal cord despite... 

Hcxanc can be determined in biological fluids and tissues and breath using a variety of analytical methods. Representative methods are summarized in Table 6-1. Most methods utilize gas chromatographic (GC) techniques for determination of -hexane. The three methods used for preparation of biological fluids and tissues for analysis are solvent extraction, direct aqueous injection, and headspace extraction. Breath samples are usually collected on adsorbent traps or in sampling bags or canisters prior to analysis by GC. 

The most commonly used methods for measuring mirex in blood, tissues (including adipose tissue), milk, and feces are gas chromatography (GC) or capillary GC combined with electron capture detection (ECD) or mass spectrometry (MS). Tables 6-1 and 6-2 summarize the applicable analytical methods for determining mirex and chlordecone, respectively, in biological fluids and tissues. 

GC-.MS and LC-MS provide highly sensitive and specific methods for determining drugs and their metabolites in biological fluids and tissues. 

In order to determine an optimum dosage regimen for a drug and to determine its mode of metabolism, methods for analysis of the drug and its metabolites in blood, urine and tissues have to be developed. Analysis of drugs in biological fluids and tissues by GC is quite common although GC-MS (see Ch. 9) has replaced many GC methods which are reliant on less selective types of detector. 

Monitoring human exposure to fluoride can be accomplished with varying degrees of accuracy through the analysis of several biological fluids and tissues. The concentrations of fluoride in plasma, serum and urine have been considered... 

The analytical methods used to quantify diazinon in biological and environmental samples are summarized below. Table 6-1 lists the applicable analytical methods for determining diazinon in biological fluids and tissues and Table 6-2 lists the methods used for determining diazinon in environmental samples. 

Materials in which these elements are determined by flame spectrometry include water, glasses, cement, soils, fertilizers, plant materials, biological fluids and tissues, petroleum products and metallurgical products. 

The microbiological assays recommended for moxalactam are performed with gram-negative organisms. Specifically, Escherichia coli is used for potency determinations with the bulk material and the final dosage forms, Providencia stuartii with biological fluids and tissues, and Pseudomonas aeruginosa for the assay of moxalactam in susceptibility discs. 

The contribution of lipophilic antioxidants is small. Escobar et al. (E5) found that the TAC of lipophilic antoxidants in blood plasma was 16.5 1.5 pM and corresponded almost exclusively to a-tocopherol the concentration of this compound in the blood plasma, analyzed independently, was 17.6 0.3 pM. Popov and Lewin (PI9) found TAC of lipid-soluble antioxidants in blood plasma to be 28.0 8.1 /u.M, a value comparable with the concentration of a-tocopherol (20.5 6.6 /U.M). These (and other) results confirm that a-tocopherol is the main lipid-soluble antioxidant of blood plasma (II) and indicates that the contribution of the lipid-soluble antioxidants to TAC of blood plasma is in fact negligible, taking into account that TAC of human blood plasma is of the order of 1 mM (see later). The contribution of ascorbic acid is also low. This situation may differ considerably in other biological fluids and tissue homogenates. In seminal plasma, the concentration ratio of ascorbate to urate is about 1 (G3). Ascorbate and urate contribute 29% of the fast TRAP of human seminal plasma the share of proteins and polyphenolic compounds is 57%, whereas tyrosine contributes 15% of the slow TRAP (R14) (Table 7). Ascorbate and uric acid account for about half of TAC of human tears (K3). TAC of urine is determined mainly by urate and proteins (K5). 

K6. Kohen, R., Beit-Yannai, E., Berry, E. M., and Tirosh, O., Overall low molecular weight antioxidant activity of biological fluids and tissues by cyclic voltammetry. Meth. Enzymol. 300, 285-296 (1999). 

Methods for measuring CDDs in biological fluids and tissues are available. Adipose tissue and liver are the primary storage site for CDDs and tissue samples have been analyzed in several studies. It was demonstrated that the relative (lipid-based) levels of 2,3,7,8-TCDD are similar in hepatic and adipose tissues (Leung et al. 1990a) and between adipose tissue and serum (Patterson et al. 1988 Schecter et al. 1990) from the same patients. However, this was not the case for more highly chlorinated dioxins for... 

The toxicological analysis is essential in the clinical and medicolegal process, aimed at seeking evidence of the presence of psychoactive substances in biological fluids and tissues. The fields of intervention of a clinical toxicology laboratory are mainly two ... 

Detectors used to identify DEHP include the electron capture detector (ECD) (Mes et al. 1974 Vessman and Rietz 1974) and the flame ionization detector (FID) (Albro et al. 1984). When unequivocal identification is required, a mass spectrometer (MS) coupled to the GC column might be employed (Ching et al. 1981 a EPA 1986 f Hillman et al. 1975 Sjoberg and Bondesson 1985). Analytical methods for the determination of DEHP in various biological fluids and tissues are summarized inTable7-l. 

Biodistribution analysis is conducted at the molecular level. The current gold standard is a quantitative polymerase chain reaction (Q-PCR) assay that detects the number of vector copies per microgram of genomic DNA. Biological fluids and tissue samples are carefully harvested (to avoid crosscontamination) from control and gene therapy product-injected animals at... 

No analytical methods specifically used for the determination of tetryl in biological fluids and tissues were located. One attempt to develop a method for detecting tetryl in animal tissues using high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection was unsuccessful because of suspected metabolism and binding of the parent compound and/or metabolites to macromolecules (Army 1981a). However, methods were located for the detection of the tetryl metabolites, picric acid and picramic acid, in urine and for the analysis of tetryl in hand swabs. Table 6-1 is a summary of methods used to determine tetryl metabolites in urine and tetryl in hand swabs. 

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