Components In Biological Samples Research Articles

The levels of kerosene components in biological samples after repeated dermal exposure to kerosene in rats

The current study was experimentally investigated using rats whether or not kerosene components are accumulated from daily repeated dermal exposure. Rats received daily 1 h-exposure to kerosene for 5 days (5K), daily 1 h-exposure for 4 days and left for 1 day (4KL), a single 1 h-exposure (1K), a single 1 h-exposure and left for 1 day (1KL), or a single 1 h-exposure, sacrificed and left dead for 1 day (1KLD). Kerosene components, trimethylbenzenes (TMBs) and aliphatic hydrocarbons (AHCs) in blood and tissues were determined by GC-MS. In blood, almost the same concentrations of TMBs were detected in the rats sacrificed immediately after exposure (5K, 1K and 1KLD), and only trace levels were detected in the rats sacrificed 1 day after exposure (4 and 1KL). Almost the same levels of AHCs in blood were detected among groups except for the rats sacrificed 1 day after a single exposure (1KL), in which AHCs were slightly lower. These results suggest that (1) AHCs tend to be accumulated from daily exposure, while TMBs do not, (2) the proportions of detected kerosene components in blood can be an indicator of whether the last exposure occurred just before death or not, (3) the kerosene levels last at least 1 day without blood circulation.

The use of 96-well Scintiplates to facilitate definitive metabolism studies for drug candidates

Semi-quantitative analysis of the drug-related components in biological samples collected during definitive metabolism studies using radiolabelled drug candidates is commonly achieved by HPLC profiling, using either on-line radiochemical detection or off-line liquid scintillation counting (LSC) following collection of the HPLC eluent into vials. However, although the use of LSC with vials has high sensitivity, the approach is time-consuming, laborious and destructive, whilst on-line detection methods are inappropriate for samples with low-levels of radioactivity (commonly the case with plasma samples). The use of 96-well microtitre plates (Scintiplates) for fraction collection during HPLC profiling provides a sensitive, effective and efficient alternative method for the semi-quantitative analysis of radiolabelled components in biological samples. Furthermore, the approach is non-destructive, such that subsequent identification of the isolated components can be achieved. Although the Scintiplate methodology is not appropriate for the analysis of excreta samples, where quenching of the radiochemical signal by endogenous components was observed, the approach was demonstrated to be valid for the relative quantification of [ 14 C ]-labelled material in plasma samples for all species investigated. In addition, good sensitivity was observed, with a counting efficiency of 79% for [ 14 C ], such that a drug-related component accounting for 10–15 dpm is quantifiable. The utility of the methodology for profiling circulating metabolites was demonstrated by the analysis of a rat plasma sample following oral administration of [ 14 C ]-UK-349,862. The Scintiplate approach and subsequent mass spectrometric analysis resulted in the relative quantitation and specific characterisation of circulating metabolites accounting for 93% of the total plasma radioactivity.

Dermal absorption of kerosene components in rats and the influence of its amount and area of exposure

The influences of amount and area of dermal exposure to kerosene upon the levels of kerosene components in biological samples were examined in vivo and in vitro. Thirty-two rats were randomly divided into four groups and exposed to kerosene through the abdominal skin for 2 h. The amounts (soaked in cotton) and area of kerosene exposed were 1 ml/4 cm 2 in Group I, 4 ml/4 cm 2 in Group II, 4 ml/16 cm 2 in Group III and 16 ml/64 cm 2 in Group IV. Before, then 5, 10, 20, 30, 45, 60, 90 and 120 min after exposure, 0.5 ml of blood was collected. Solid tissue samples, including the exposed skin area, were harvested at 120 min. Kerosene components were analyzed by gas chromatography/mass spectrometry. Trimethylbenzens (TMBs) that are easily absorbed kerosene components, appeared at 5–20 min. The time course changes in TMB levels in blood were significantly different between Groups I and II or Groups I and III, and almost identical between Groups II and III. Similar trends were observed in tissue samples at 120 min. High concentrations of aliphatic hydrocarbons (AHCs) were detected in the exposed skin and the AHC levels were dependent on the amount of kerosene exposed per unit area. These results suggest that (1) dermal absorption of kerosene occurs soon after dermal exposure started, (2) absorption of TMBs is influenced by the total amount of kerosene rather than area of exposure, and (3) AHCs remaining in the skin at significant levels are influenced by the amount of kerosene per unit area exposed.

Enantioselective determination of persistent and partly degradable toxaphene congeners in high trophic level biota

Enantiomer separation of chiral toxaphene components in biological samples was studied by application of different chiral stationary phases based on modified cyclodextrins. Several pairs of enantiomers were resolved on permethylated β-cyclodextrin (β-PMCD), among them 2- endo,3- exo,5- endo,6- exo,8,8,9,10-octachlorobornane (B8-1412), which was not enantiomerically resolved on tert-butyldimethylsilylated β-cyclodextrin (β-BSCD). The latter column was applied to determine the enantiomer ratios (ERs) of 2- endo,3- exo,5- endo,6- exo,8,8,10,10-octachlorobornane (B8-1413 or P-26) in brain tissue of three seal species. The ER of B8-1413 (P-26) in brain was virtually racemic as well as those of the two persistent and chiral components of technical chlordane, 1- exo,2,2,4,5,6,7,8,8-octachloro-3a,4,7,7a-tetrahydro-4,7-methanoindane ( trans-nonachlor III or MC 6) and 1- exo,2- endo,3- exo,4,5,6,8,8-octachloro-3a,7,7a-tetrahydro-4,7-methanoindane (U82). In contrast, B8-1412 and 2- exo,5,5,8,9,9,10,10-octachlorobornane (B8-2229 or P-44) were significantly enantiomerically enriched in several samples of high trophic level biota. 2,2,5,5,8,9,9,10,10-Nonachlorobornane (B9-1025 or P-62), a chlorobornane metabolisable by seals and the presumable precursor of B8-2229 (P-44), was also enantiomerically enriched in seal blubber. These results confirm the assumption that some less persistent toxaphene components may be significantly degraded in biological samples. Enantioselective gas chromatography provides the information that such a degradation is happening by the characteristic change of the ratio of the two enantiomers in the respective tissues.

The First International Conference on the Environmental Health and Safety of Jet Fuel

The First International Conference on the Environmental Health and Safety of Jet Fuel

Applications of Capillary Electrophoresis in Nephrology

Capillary electrophoresis has recently emerged as a powerful technique for separating components in biological samples. A family of separation methods capable of handling a diverse range of samples has been developed, the sample volumes required are very small and a wide range of specialised detectors can be employed. This review examines some methods with particular application to the analysis of urine and tubular fluid samples and references relevant applications.

A sensitive fluorogenic enzyme linked immunosorbent assay for the detection of Vipera russelli venom.

A highly sensitive fluorogenic enzyme-linked immunosorbent assay (FELISA) has been adapted for the detection of Vipera russelli venom. The assay sensitivity was observed to be 0.1 pg/ml (1 x 10(-13) g/ml). Venoms from snakes of the Vipera group exhibited a high degree of cross-reactivity when tested with the antibody raised against V. russelli venom. With the exception of venom from Naja naja, all the tested venoms from unrelated families also showed cross-reactivity. This procedure is useful for detecting snake venom or its components in biological samples.

Pre-ashing of biological samples ? a sample preparation technique for solid sampling ZAAS

A pre-ashing method by a conventional electrothermal furnace was used as a concentration technique for powdered biological samples in the solid sampling technique with GF-ZAAS. A relationship equation between the concentration factors and the concentrations of main inorganic components in biological samples has been established, and it has become possible to calculate the concentration factors, if the total concentration of K, Na, Mg and Ca, or total concentration of K and Mg, or the concentration of K only are known. The proposed method has been successfully applied to the direct determination of Co, Ni, Mn and Pb at the μg/kg levels in biological samples.

An implification technology for improving sensitivity when measuring components in biological samples

A new technology for improving the sensitivity in measuring components in biological samples is described. The method is based on the use of spherical microbeads (detection beads) which contain a large amount of immobilized enzyme and a reagent with biospecific affinity for the component to be detected. These microbeads have been used in a ‘sandwich reaction’ for visualization of P-fimbriated Escherichia coli which has a known receptor structure (Gal(α1–4)Gal(β)). In the initial step the bacteria were enriched on a solid support (e.g., a plastic film or beads (> 150 μm) to which the receptor structure had been covalently bound. In the next step detection beads coupled with enzyme and receptor structure were added and finally a chromogenic substrate for the enzyme was used for visualization. A sensitivity of 10 5 bacteria/ml was reached. The detection beads are of general utility and might be useful for the detection of lectins on other pathogens.