Tissues determination

Dry weight of living tissues, determined by long-wavelength x-ray absorptiometry, 297-300 Duane and Hunt, law of, 7 Dynodes, 56... 

Tin plate, thickness of tin coating on, determination by x-ray spectrography, 148, 149, 157, 158 Tissues, determination of dry weight by absorptiometry, 297-300 Tissue sections, biological, determination of mineral elements in, 301-305 Titanium, as internal standard in vanadium determination, 188 determination by x-ray emission spectrography, 222, 329 trace analysis by x-ray emission spectrography, 163, 225-229 Topaz, as analyzing crystal, 116-118, 220, 318-327 Total reflection, 112, 117... 

Janak K, G Becker, A Colmsjo, C Ostman, M Athanasiadou, K Valters, A Bergman (1998) Methyl sulfonyl polychlorinated biphenyls and 2,2-bis(4-chlorophenyl)-l,l-dichloroethene in gray seal tissues determinated by gas chromatography with electron capture detection and atomic emission detection. Environ Toxicol Chem 17 1046-1055. 

Distribution. Generally the highest concentration of PCB residues in fish are in tissues of high lipid content. In Table V juvenile coho salmon were fed equal amounts of three chlorobi-phenyls for 117 days. Fish were then killed and lipid content and PCB concentration of various tissues determined (33). Tissues are arranged from top to bottom in order of increasing PCB concentration. For most tissues, but not all, as lipid content increases so does PCB concentration. Lipid content and PCB concentration are low in liver and white muscle, intermediate in spinal column and lateral line muscle, and high in adipose tissue. Lipid content cannot be the sole determinant of PCB concentration in fish tissues because a discrepancy exists between lipid content of brain, heart and spleen and PCB concentration. 

Relaxation times, MT ratios, and diffusion properties allow insight into the microstructure of various tissues. Determination of these parameters is possible by recording and analysing of a series of volume selective spectra, even for metabolites with relatively low concentrations in vivo. For recording series of spectra usually one parameter is changeable (e.g., inversion time TI for Ti measurements, echo time TE for T2 measurements, MT preparation for assessment of spin transfer and chemical reaction rates, or diffusion sensitizing gradients for assessment of apparent diffusion coefficients or even diffusion... 

The pharmacokinetics fCD and HlftCD after intravenous administration have been assessed (Frijlinket al., 1990). As determined at doses of 25,100, and 200 mg/kg in permanently cannulated rats, plasma levels of both CDs decreased rapidly upon injection. Within 24 h after administration, most of the doses were excreted unchanged via urine. There was no evidence forsigniLcant metabolism of the intravenously administered CDs. The pharmacokinetics and the tissue concentrations of methyl-p-cyclodextrin (MEBCD) and doxorubicin (DOX) in rabbits following administration of MEBCD and DOX, alone or in combination were studied (Grosse et al., 1999). Results indicated that DOX did not modify MEBCD pharmacokinetic proLle, but MEBCD reduced signiLcantly the distribution half-life of DOX. Tissue determination showed that MEBCD did not enhanced the cardiac accumulation of DOX. 

Van Zyl et al. reported on the diffusion of ipratropium through porcine bronchial epithelium tissue [74], In principle, ipratropium is administered via the respiratory tract by inhalation to treat pulmonary diseases associated with bronchoconstriction. Therefore, pulmonary absorption by bronchial tissue determines its local efficacy and was thus investigated in a diffusion cell in vitro. Bronchial epithelium was equilibrated in PBS and discs of 4 mm2 were mounted on that diffusion cell separating the donor and receiver compartment. The donor compartment contained the drug dissolved in PBS (1 mg/ml) and the receiving chamber was permanently flushed with a low flow (1.5 ml/h) of PBS thus allowing time-resolved fractionation for subsequent direct analysis by LC-ESI MS/MS in MRM mode. Transition to the product ion at m z 124 was monitored for quantification (Table 9). The transfer of ipratropium was characterized by the flux (about 220 ng/cm2/min) and the permeability coefficient calculated to be 1.6 x 10-8 cm/s. 

Schwan, H. P. Some tissue determinants of interactions with electric fields. Neurosci. Res. Program Bull. 1977, 15, 88-98. 

Chemcosorb C-18 (3 pm) — Amperometric Rat brain tissues determines lOpmol [150]... 

This external exposure may not necessarily correlate with internal exposure. The rate of absorption through the skin, the lung or the gastrointestinal tract determines the body burden of the chemical. Measurement of the chemical, its metabolites or products of the interaction of the chemical or its metabolites with cellular macromolecules such as proteins or DNA in body fluids and tissues determines internal exposure . Use of such biomarkers provides exact information on actual internal exposure (target dose) to an agent (Angerer et al. 2007 Boogaard 2007 Needham et al. 2007). When used in experimental studies in animals and humans they allow assessment of the individual and internal exposure as compared to external exposure. 

W. R. Waldrip, E. K. Bikolf, P. A. Hoodless, J. L. Wrana, and E. J. Robertson. Smad2 signaling in extra-embryonic tissues determines anterior-posterior polarity of the early mouse embryo. Cell, 92, 797-808, 1998. 

After absorption the blood distributes alcohol to all of the body s tissues. Since alcohol is easily dissolved in water, the proportion of water in a tissue determines the... 

Note that the effect equilibration rate constant (ke0) may be viewed as a first-order distribution rate constant. It can also be thought of in terms of the rate of presentation of a drug to a specific tissue, determined by, for example, tissue perfusion rate, apparent volume of the tissue and eventual diffusion into the tissue. The results of the data fitting in this exercise with the analgesic are Emax 4.5 EC50 0.61 ng-ml 1 and e0 0.07 h1. 

The lipophUicity of PAHs enables them to readily penetrate cellular membranes and remain in the body indefinitely. However, the metabolism of PAHs renders them more water-soluble and more excretable. Metabolism of PAHs occurs in all tissues. The metabolic process involves several possible pathways with varying degrees of enzyme activities. The activities and affinities ofthe enzymes in a given tissue determine which metabolic route will prevail. 

Van Kuijk, F.J.G.M., Thomas, D.W., Stephens, R.J. and Dratz, E.A. (1986) Occurrence of 4-hydroxy-alkenals in rat tissues determined as pentafluorbenzyloxime derivatives by gas chromatography-mass spectrometry. Biochem. Biophys. Res. Commun. 139 144—149. 

Connective tissue, which consists primarily of fibroblasts, produces extracellular matrix materials that surround cells and tissues, determining their appropriate position within the organ (see Chapter 49). These materials include structural proteins (collagen and elastin), adhesive proteins (fibronectin), and glycosaminoglycans (heparan sulfate, chondroitin sulfate). The unique structures of the proteins and carbohydrates found within the extracellular matrix allow tissues and organs to carry out their many functions. A loss of these supportive and barrier functions of connective tissue sometimes leads to significant clinical consequences, such as those that result from the microvascular alterations that lead to blindness or renal failure, or peripheral neuropathies in patients with diabetes mellitus. 

For internal quality control commercially available (certified) reference materials from e.g. BCR (Belgium, for Cd-B), Nycomed (Norway, for Cd-B and Cd-U), and NIST (U.S.A., for Cd-B and Cd-U) can be used. For tissue determinations many animal certified reference materials exist, e.g. from BCR and NIST, (see chapter on Reference Materials with a list of certfied reference materials)... 

---