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Biomedical subjects

B Bush

Publications and source records attributed to B Bush.

At least 37 records · Page 2Linked to original sources
PubMed1985

Lifetime toxicity of chloroform and bromodichloromethane when administered over a lifetime in rats.

Chloroform (CHCl3) and bromodichloromethane (CHBrCl2) are the two most common haloorganic contaminants of chlorinated drinking water. A significantly increased incidence of hepatic neoplastic nodules was found in female rats when each of these compounds was administered in drinking water to Wistar rats throughout their life span. Hepatic adenofibrosis was also produced by chronic ingestion of these two halomethanes.

Adenofibroma↗
PubMed1985

Oral dosing of rats with polychlorinated biphenyls increases urinary homovanillic acid production.

The effect of a single oral gavage with a mixture of Aroclors 1254 and 1260 on 24-h production of urinary homovanillic acid was determined in the laboratory rat. Adult male Wistar-derived rats were exposed to a single dose of corn oil, either alone or containing equal amounts of Aroclors 1254 and 1260 at a dosage of 500 or 1000 mg/kg. Urinary homovanillic acid concentrations were determined by high-performance liquid chromatography with electrochemical detection. The 500-mg/kg group showed a transient increase in homovanillic acid production, while the 1000-mg/kg group showed a biphasic response-an initial decrease (due to decreased food consumption) followed by a prolonged elevation. Only transient changes in body weight, food and water consumption, and urine output were observed. The results demonstrate that peripheral measurement of a dopamine metabolite may provide a means of monitoring changes in an important neurotransmitter system after exposure to a putative neurotoxin.

Administration, Oral↗
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↗
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↗
PubMedDate not supplied

Assimilation of polychlorinated biphenyls by a marine mollusc and comparison with a rat.

The marine mollusc Aplysia californica was fed seaweed Rhodymenia palmata contaminated with polychlorinated biphenyls (PCBs) at a high (experimental) and low (control) level for a period of 18 days in flow-through systems which limited the animals to dietary uptake. The assimilation of PCBs, determined by subtraction of fecal output from food intake, was greater at the high dosage (94 +/- 29%) than at the low dosage (84 +/- 22%). Assimilation selectivity of the different congeners favored those with lower chlorine content, and discriminated against those chlorinated in the para position on one of the rings. After assimilation, selectivity for incorporation into the hepatopancreas favored those congeners with higher chlorine contents over those with but 1 to 3 chlorines on the molecule. Similarities between incorporation into the liver of rats and into the hepatopancreas of Aplysia were found, suggesting that common mechanisms for bioaccumulation, and by extension, physiological effects, may be present in such diverse species of the animal kingdom.

Animals↗
PubMedDate not supplied

Polychlorobiphenyl (PCB) congeners in striped bass (Morone saxatilis) from marine and estuarine waters of New York State determined by capillary gas chromatography.

Edible filets of striped-bass samples (60) from the Hudson River estuary, the Atlantic shore of Long Island, and Long Island Sound were analyzed by high-resolution glass-capillary gas chromatography for 74 polychlorobiphenyl (PCB) compounds. The fish, a non-random subset of a larger sample, contained the following concentrations of total PCB residue (mean +/- the standard error of the mean). The corresponding mean values for the entire survey (N = 717) are given in parentheses: eastern Long Island Sound 1.8 +/- 0.4 (1.91 +/- 0.1) mg/kg; western Long Island Sound, 1.9 +/- 0.2 (2.51 +/- 0.1) mg/kg; eastern Atlantic shore, 3.0 +/- 0.5 (2.45 +/- 0.2) mg/kg; western Atlantic shore, 7.5 +/- 1.9 (3.04 +/- 0.2) mg/kg; Hudson River, 15 +/- 3 (6.19 +/- 0.4) mg/kg. All the samples contained PCB residues derived from Aroclors 1242, 1016, 1254, and 1260 but none of the residue present came from Aroclor 1221 as evidenced by the complete absence of 4-chlorobiphenyl from the fish. Fish from the Hudson River and the majority from the Atlantic shore of Long Island contained 2,2'- and 2,6-dichlorobiphenyls indicating recent exposure to Hudson River PCBs. On this basis, there was evidence that a subpopulation of fish was not exposed to the Hudson River PCB source. The detailed PCB congener make-up of the typical residue found in these fish differs from that found in the majority of human food-stuff in that it contains a proportionately large amount of mono- through tetra-chlorinated PCB. The mean concentration of the more toxicologically suspect congeners which are not readily degraded by mammals and birds (those with two 4-substituents) comprise less than 1 ppm in Long Island Sound fish.

Animals↗