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Biomedical subjects

L D Koller

Publications and source records attributed to L D Koller.

At least 91 records · Page 5Linked to original sources
PubMed1973

Pathology of polychlorinated biphenyls in rabbits.

Rabbits were administered, orally, 300 mg of polychlorinated biphenyl Aroclor 1221, 1242 or 1254 once a week for 14 weeks. Elevated SGPT and SGOT levels occurred in the male and female 1254- and male 1242-treated rabbits as early as 2 weeks. The female 1242-treated rabbits had increased SGPT and SGOT activities at 4 and 8 weeks, respectively. These serum enzyme activities in the 1221-treated rabbits were similar to the controls during the 14-week period. Serum cholesterol concentrations were moderately elevated in the 1254-treated males throughout the experiment. The BUN, serum proteins, liver ALA-synthetase and hematologic values were similar in all groups. The livers in the 1254- and 1242-treated rabbits were significantly enlarged compared to the 1221-treated and control animals. The earliest change was megalohepatocytosis which was followed by subcapsular midzonal necrosis. In the 1254-treated rabbits, the midzonal necrosis was diffuse and frequently included most of the central part of the lobule. Fibrous connective tissue replaced the necrotic part of the lobules in the more severely affected livers. The rough endoplasmic reticulum in the livers of the 1254-treated rabbits appeared to have been destroyed. There was also atrophy of the uteri in the 1254-treated rabbits.

5-Aminolevulinate Synthetase↗
PubMedDate not supplied

Neopterin values in selected groups of normal animals.

To establish baseline information on neopterin concentrations in livestock, companion and laboratory animals and identify the factors that may influence these concentrations, blood samples were taken from normal dairy cattle, horses, llamas, dogs, cats and rats of varying ages and sexes. In addition, neopterin concentrations in normal, adult equines were compared with those found in racing Thoroughbreds. There were no differences due to sex, sexual maturity, pregnancy, castration, or age. For all ages and sexes combined, mean neopterin concentrations were significantly lower in llamas (2.27+/-0.33 nmol litre(-1)) and rats (2.13+/-0.21 nmol litre(-1)) when compared with the other species tested. Racing Thoroughbreds demonstrated higher neopterin values than adult equines not in training (3.54+/-0.64 vs 3.13+/-1.02 nmol litre(-1)).

Aging↗
PubMedDate not supplied

2,3,7,8-Tetrachlorodibenzo-p-dioxin co-stimulates staphylococcal enterotoxin beta (SEB) cytokine production and phenotypic cell cycling in Long-Evans rats.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an environmental contaminant that is considered to be a potent immunotoxicant. In the present study, we examined the effect of 25 micrograms/kg TCDD on cytokine production and T lymphocyte phenotype, cell cycling and receptor activity in female Long-Evans rats that had been injected with 50 micrograms of Staphylococcal Enterotoxin B (SEB). In the SEB-injected rats, TCDD increased the serum levels of interleukin-2 (IL-2) but did not affect the serum levels of interleukin-1 (IL-1), interleukin-6 (IL-6) or tumor necrosis factor (TNF). The ability of spleen cells and peritoneal cells to produce cytokines in response to SEB restimulation in vitro was also evaluated. TCDD exposure significantly enhanced IL-2 production by spleen cells from SEB-primed rats after 6 h or 24 h in cultures co-stimulated with SEB in vitro. However, TCDD treatment did not alter the production of IL-6 and TNF in these cultures. Although TCDD did not influence the production of IL-6 and TNF in peritoneal cells from SEB-primed rats with SEB restimultion in vitro, IL-1 production was significantly increased at 2 h. Both the kinetics and extent of SEB-induced IL-2 receptor (IL-2R) and T-cell receptor (TCR) expression on CD4+ cells was unaffected by TCDD. TCDD did not significantly alter the percentage or the total numbers of CD4+ and CD8+ subpopulations at various times after SEB injection. However, flow cytometric analysis showed that TCDD exposure increased the percentage of both CD4+ and CD8+ cells cycling in the S and G2M phase. TCDD, in the absence of SEB priming, did not affect any of the immune parameters tested. Nevertheless, collectively these results showed that TCDD can enhance the production of IL-2 and the percentage of CD4+ and CD8+ cells cycling in SEB-exposed Long-Evans rats. Histopatholgically, there were not observable effects of SEB on lymphoid organs while thymic atrophy and diffuse hepatocellular hypertrophy was observed in the TCDD-treated animals.

Animals↗
PubMedDate not supplied

Synergism of methylmercury and selenium producing enhanced antibody formation in mice.

Mice fed 1, 5, and 10 ppm methylmercury plus 6 ppm selenium for 10 wk had a significant increase in antibody synthesis. Since methylmercury singly depresses antibody synthesis and the response was greater than that produced by selenium alone, synergism between methylmercury and selenium occurred. In this case, the synergism is considered to be advantageous to a host, while exposure by other combinations of environmental contaminants may be detrimental. Mercury concentrations in the kidney were markedly elevated when methylmercury and selenium were administered simultaneously compared to when methylmercury was given without selenium supplement. These results indicate that data collected from individual pollutants may not be of value in predicting responses to multiple exposure.

Animals↗
PubMedDate not supplied

Polycythemia produced in rats by environmental contaminants.

Polycythemia developed in progeny from mothers who were exposed during pregnancy to a combination of methylmercury chloride plus ethylurea and sodium nitrite. The polycythemia occurred as early as one month of age and as many as 24% of the offspring developed the polycythemic condition. Many features of this condition are similar to those of polycythemia vera in man, such as elevated hematocrits and white and red blood cell counts, splenomegaly, and hyperplasia of bone marrow accompanied by megakaryocytosis.

Animals↗
PubMedDate not supplied

Lead-cadmium interaction: effects on viral-induced mortality and tissue residues in mice.

Simultaneous exposure to lead and cadmium is highly probable due to common environmental sources of exposure. Mice were exposed simultaneously for 10 wek to lead and cadmium and effects were observed on accumulation of the metals in tissues and susceptibility to viral challenge. The incidence of viral-induced mortality was enhanced in all groups of mice exposed to lead and suppressed in groups of mice treated with cadmium. Mice exposed to both lead and cadmium had mortality rates intermediate to those observed after exposure to the individual metals. Lead and cadmium residues in tissues of mice exposed to both metals, as compared to residues in tissues of mice which received lead or cadmium only, indciated that interaction occurs in regard to metabolism, storage, and excretion of these elements. Chronic coexposure to lead and cadmium appears to alter certain effects produced by exposure to each metal alone.

Animals↗
PubMedDate not supplied

Pathology of "toxic oils" and selected metals in the MRL/lpr mouse.

The Toxic Oil Syndrome epidemic that occurred in Spain in 1981 and affected nearly 20,000 people was caused by ingestion of oil mixtures that contained analine-denatured rapeseed oil. To date, an animal model in which to identify the actual etiologic agents(s) and to investigate the pathogenesis of the disease has not been discovered. In this study, the MRL/lpr was used to assess the histopathological response of 3 "toxic oils" and 3 metals. The oils tested were a denatured rapeseed oil collected from a family who were affected by the Toxic Oil Syndrome epidemic in Spain (CO756) plus two synthesized oils (RSD and RSA). Female mice, 7 weeks of age, received an undiluted (neat) or a 1:10 diluted dose of each oil; mercury (50 ppm), cadmium (100 ppm), or lead (50 ppm). Half of each group was killed after 5 weeks of exposure and the remaining mice after 10 weeks of exposure. Body and organ weights (liver, kidney, thymus, and spleen) were recorded and selected organs were collected for histopathology. Ten weeks after treatment, body weights (BW) of the cadmium and lead groups were significantly suppressed, and the body weight of the C0756-neat group was significantly increased compared to their respective controls. Kidney/BW were decreased in the RSA-neat and RSA 1:10 groups after 10 weeks of exposure, and the kidney/BW in the mercury and cadmium groups were increased. Spontaneous development (12 weeks of age) and progression (17 weeks of age) of histopathological lesions are described for selected organs examined in the naïve mice as are changes that resulted from exposure to the "toxic oils" and metals. C0756-neat, mercury, and lead suppressed progression of the glomerulonephritis that normally occurs in the MRL/lpr mouse. Also of interest were lesions that included mononuclear cuffing of hepatic bile ducts, progression of the granulomas that formed in the renal glomeruli, vessels in the lymphoid organs that contained tightly packed lymphocytes, and the presence of plasma cells in the thymus. All 3 oils stimulated early development of the lymphoproliferative syndrome characteristic of the MRL/lpr mouse as demonstrated by an increase in the thymus/BW and spleen/BW ratios after 5 weeks of treatment. These data contribute to our knowledge of spontaneous disease progression in the thymus, spleen, lymph nodes, and kidneys in the MRL/lpr mouse and the effects of 3 different "toxic oils" and metals on the development and progression of those lesions.

Animals↗