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Biomedical subjects

B Bush

Publications and source records attributed to B Bush.

At least 55 records · Page 3Linked to original sources
PubMed1985

Improvements in glass capillary gas chromatographic polychlorobiphenyl analysis.

Separation of a 1:1:1:1 calibration mixture of Aroclors 1221, 1016, 1254, and 1260 on soda glass capillaries coated with Apolane (C-87) or Apiezon L is described. Polychlorobiphenyl congener structures are assigned to 112 separated and partially separated zones. The quantitative composition of Aroclor 1221 is reported. The performance of the two stationary phases on different lengths of laboratory and commercially prepared capillaries is compared and found to be very similar. Aroclors 1221, 1016, 1254, and 1260 are employed (1:1:1:1) for the primary calibration mixture because they contain all components of the commercial materials which pollute the environment; they are also easily obtained from the U.S. EPA Repository so that the method can be used in any laboratory by employing the calibration data given here.

Chromatography, Gas↗
PubMed1985

Polychlorinated biphenyls induce regional changes in brain norepinephrine concentrations in adult rats.

Adult male rats were gavaged with a mixture of Aroclor 1254 and 1260 at a dose level of either 500 or 1000 mg/kg and were killed on post-gavage Days 1, 3, 7 and 14. Total PCB concentrations and concentrations of norepinephrine were determined in the frontal cortex, hypothalamus, hippocampus, and brainstem. Brain regions behaved differently from each other in terms of both initial concentrations and redistribution patterns of PCBs following exposure. Norepinephrine concentrations were reduced in the frontal cortex and hippocampus but were unaffected in the hypothalamus and brainstem. These results demonstrate that the mature mammalian nervous system is sensitive to a brief exposure to PCBs, that the neurological effects are reversible and dependent on the presence of PCBs in the tissue, and that there are regional brain differences with regard to PCB concentrations and direction and magnitude of neurochemical change induced by the PCBs.

Animals↗
PubMed1983

Direct determination of 4-hydroxy-3-methoxyphenylacetic (homovanillic) acid in urine by high-performance liquid chromatography with amperometric detection.

The improvement of high-performance liquid chromatographic analysis with electrochemical detection for urinary homovanillic acid is described. The method permits the chromatographic resolution of authentic homovanillic acid from coeluting interfering compounds in human and nonhuman primate, and rat urine. The electrochemically derived results are compared with post-column derivatized fluorescence results, and quality-control checks necessary to maintain assay precision in automated analysis are described.

Animals↗
PubMed1983

High resolution gas chromatographic analysis of nonpolar chlorinated hydrocarbons in human milk.

A gas chromatographic method is described for the analysis of human milk to determine polychlorinated biphenyls (PCBs) as 72 congeners plus p,p'-DDE, mirex, hexachlorobenzene, and octachlorostyrene. The detection limit for individual compounds is about 0.05 ng/g when 30 g milk is analyzed. Total PCBs can be estimated with a detection limit of 1-5 ng/mL milk. Analytical precision is better than +/- 10% for all compounds at 20-50 ng/mL whole milk.

Chromatography, Gas↗
PubMed1982

Evaluation of erythrocyte protoporphyrin and zinc protoporphyrin as micro screening procedures for lead poisoning detection.

Seven hundred and three blood samples from children were analysed for lead by Delves cup atomic absorption, for protoporphyrin by solvent extraction and fluorescence, and for zinc protoporphyrin with two manufacturers' models of automated front-face fluorimeter (haemato-fluorimeter). This power of protoporphyrin analysis for predicting the level of lead in blood was found to be poor. Up to 30% of children with lead concentrations of greater than or equal to 40 g/100 ml (greater than or equal to 1.93 mumol/l) and nearly 60% of children with greater than or equal to 30 microgram/100 ml (greater than or equal to 1.45 mumol/l) would remain undetected if protoporphyrin analysis were used for screening with an action level of 60 microgram/100 ml (1.07 mumol/l) for the porphyrin analysis. The predictive power of protoporphyrin analyses improves with the age of the child, indicating that the less expensive protoporphyrin test may be acceptable for older children, if by this means a large population of children at risk can be screened.

Child↗
PubMed1980

High-performance liquid chromatographic determination of protoporphyrin and zinc protoporphyrin in blood.

Zinc protoporphyrin and protoporphyrin free acid in blood were determined by high-performance liquid chromatography on a C18 column. Results for 63 human blood samples obtained through a lead poisoning detection program compared favorably with the widely-used ethyl acetate--acetic acid extraction determination. Blood from 16 rats which had been maintained on water heavily spiked with chloroform or bromodichloromethane and blood from a lead-poisoned cow were examined by this procedure.

Animals↗
PubMed1980

Accumulation of polychlorinated biphenyls in american shad during their migration in the Hudson River, spring 1977.

Fifty-two female American shad (Alosa sapidissima) were collected during the spring of 1977 at two sites on the lower Hudson River, 27 miles and 75 miles from the river mouth. The fish were extracted with hexane, and the extracts were analyzed by electron-capture gas chromatography (EC-GC) and by GC/mass spectrometry (MS), PCBs were quantitated by EC-GC, and the concentrations were compared by fish length and by site. Fish collected from the downstream site contained a mean PCB concentration of 2.0 +/- 1.0 microgram/g, wet weight; fish from the upstream site contained a mean PCB concentration of 6.1 +/- 2.6 microgram/g, wet weight. Aliquots of the hexane extracts were fractionated before analysis by GC/MS. The presence of PCBs was confirmed, and DDE and the alkane series from C22 through C26 were detected. American shad are saltwater fish that only enter fresh water to spawn. Because they do not feed in fresh water before spawning, they may be used as an indicator of water contamination.

Animals↗
PubMed1977

Toxicity and persistence of low-level PCB in adult wistar rats, fetuses, and young.

Aroclor 1254 was fed to female and male rats daily for 9 weeks at a dose of 6.4 mg/kg in their drinking water. Control animals received plain tap water plus the emulsified (0.15% Tween 80). Elevated mixed function oxidase (MFO) activity appeared to be due to 2,4,5,2',4',5'- and 2,4,5,2'3'4'-hexachlorobiphenyls, since only these compounds were present to any degree in the tissues of the animals when MFO activity persisted after termination of exposure. The placenta apparently is an effective barrier to PCB transfer.

Animals↗
PubMed1976

Identification of gasoline contamination of ground-water by gas chromatography.

Individual components that make up different grades of gasoline - or gasolines of the same grade produced by different manufacturers - are resolved and identified by gas chromatography using packed columns and a flame ionization detector. Contaminants at levels as low as 0.5 mu1/1 may be identified by the method if samples of gasoline from the source of contamination can be obtained for comparison. The uniqueness of this method is that it can be applied for routine analysis without the use of sophisticated complements for the gas chromatograph.

Chromatography, Gas↗
PubMed1975

Analytical response of polychlorinated biphenyl homologues and isomers in thin-layer and gas chromatography.

Except for pure synthetic polychlorinated biphenyl (PCB), estimation methods of PCB by thin-layer and gas chromatography with electron capture detection give comparable results. Both give a good estimate of the true mass of a biologically modified residue, but where mostly hexachlorobiphenyls and above make up the residue, the estimate will be up to 50% too high. The Coulson detector does not, in our hands, yield comparable results with modified residues: the reason for this difference is not clear at present.

Chromatography, Gas↗