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Biomedical subjects

J A Moore

Publications and source records attributed to J A Moore.

At least 145 records · Page 8Linked to original sources
PubMed1984

Acyclovir for herpes simplex infections.

Herpes simplex infection can appear in a wide variety of clinical presentations. The primary herpes infection can be recognized as grouped vesicles on an erythematous base which may ulcerate. Laboratory confirmation can be made by a rapid Tzanck smear or culture. When used appropriately, acyclovir is effective in treating herpes infection. The drug is available in topical and intravenous forms, and an oral form is being investigated. Acyclovir-resistant viruses have already appeared.

Acyclovir↗
PubMed1984

Selenium concentrations in plasma of patients with arteriographically defined coronary atherosclerosis.

A prospective epidemiological study (Lancet ii: 175-179, 1982) implicates low concentrations of selenium in plasma in coronary atherogenesis. We examined this relationship more directly by fluorometry of selenium in the plasma of 91 hospitalized patients who were being examined by coronary arteriography for clinical evaluation of chest pain. We observed a significant, inverse correlation between the plasma selenium and severity of coronary atherosclerosis. These results confirm those of the epidemiological studies, but the role, if any, of selenium in atherogenesis still is unclear. Its concentration in plasma is decreased by ethanol and cigarette use; possibly this is the mechanism of its relation to hypertension and atherosclerosis.

2-Naphthylamine↗
PubMed1983

Effects of a polybrominated biphenyl mixture in the rat and mouse. I. Six-month exposure.

A 1973 environmental accident in Michigan resulted in exposure of humans via the food chain to polybrominated biphenyl (PBB). To better characterize the toxicity of the halogenated polycyclic aromatic hydrocarbon class of chemicals, rodents were dosed with PBB and their target organs examined for morphological, histological, biochemical, and selected endocrine changes. Male and female rats and mice were given 125 po doses of PBB over a 6-month period at 0.1, 0.3, 1.0, 3.0, and 10.0 mg/kg of body weight/day (5 days/week). There was a dose-related decrease in body weight gain in both male and female rats and male mice. Thymus weights were significantly decreased in all rats exposed to 0.3 mg/kg or more of PBB. Dose-related hepatotoxic effects were observed in both rats and mice characterized by marked increase in liver weight with accentuation of hepatic lobular markings. Microscopically, there were moderate to marked swelling, disorganization, and single cell necrosis of hepatocytes, fatty infiltration, bile duct proliferation, and presence of atypical hyperplastic foci. Hepatic porphyrin levels were markedly increased in both rats and mice primarily in females. There was a significant decrease in serum thyroxine (T4) and triiodothyronine (T3) suggesting that PBB may interfere with thyroid hormone secretion. There was a significant dose-related increase in serum cholesterol and gamma-glutamyl transpeptidase, and a decrease in serum glucose.

Animals↗
PubMed1983

Effects of a polybrominated biphenyl mixture in the rat and mouse. II. Lifetime study.

This study was undertaken to characterize the long-term toxic and carcinogenic potential of a polybrominated biphenyl (PBB) mixture in rats and mice of both sexes. Fischer 344 rats and B6C3F1 mice were given 125 po doses of PBB over a 6-month period at 0 (control), 0.1, 0.3, 1.0, 3.0, and 10.0 mg/kg body weight/day (5 days/week) and observed for an additional 23 months for rats and 24 months for mice (lifetime observation). The treatments (0.3 mg/kg or higher dosages) shortened the survival time in male rats whereas no such effect was observed in treated females. There was also evidence of shortened survival time in mice treated with 10.0 mg/kg PBB. As observed by uv light, hepatic porphyrin markedly increased at the 6-month observation, then tended to decrease, primarily in mice, following cessation of exposure. Significantly higher incidences of atypical hepatocellular foci, neoplastic nodules, hepatocellular carcinomas, and cholangiocarcinomas were observed in exposed rats. The incidence of hepatocellular carcinoma was also increased in both male (95%) and female (88%) mice (highest dose level) compared with control male (48%) and female (0%) mice. The incidence of hepatic neoplasms appeared to be dose dependent in both species. Liver tumors were observed primarily in those groups of animals to which PBB was given in doses sufficient to induce readily observable hepatic toxicity. Under the conditions of this experiment, polybrominated biphenyl mixture (Firemaster FF-1) was carcinogenic for Fischer 344 rats and B6C3F1 mice of both sexes. Lesions included neoplastic nodules, hepatocellular carcinomas, and cholangiocarcinomas in rats and hepatocellular carcinomas in mice. Other manifestations of toxicity included porphyrogenic effects and hepatotoxicity. A significantly higher incidence of chronic progressive nephropathy was observed in male rats of the 1.0, 3.0, and 10.0 mg/kg dosage groups when compared with control males. Gastric ulcers and hyperplastic gastropathy of the glandular portion of the stomach were observed more frequently in male rats, primarily in the high dosage groups.

Animals↗
PubMed1983

The effect of age and exposure duration on cancer induction by a known carcinogen in rats, mice, and hamsters.

Female Golden Syrian hamsters, F-344 rats, Swiss CD-1 mice, and B6C3F1 hybrid mice were exposed 6 hr/day, 5 days/week to carcinogenic levels of vinyl chloride (VC) for 6, 12, 18, or 24 months (rats and hamsters only). Other groups of rodents were held for 6 or 12 months and then exposed for 6 or 12 months. At the end of the study the incidence of VC-induced neoplasms was compared in each of the groups to assess the effects of duration of exposure and age at the start of exposure on carcinogenicity of VC. In rats, with early initial exposure, hemangiosarcomas, hepatocellular carcinomas, and mammary gland carcinomas occurred with increasing incidence with longer exposure duration. Rats held for 6 months before exposure developed VC-related neoplasms, while rats held 12 months before the start of exposure failed to show a significantly increased incidence of these neoplasms. In hamsters, hemangiosarcomas, mammary gland carcinomas, gastric adenocarcinomas, and skin carcinomas resulted from VC exposure. The highest incidence of malignant neoplasms occurred in hamsters exposed for the first 12 months, whereas exposure begun after 12 months of age did not cause neoplasms. In both strains of mice, VC exposure during the first 6 months of the experiment induced a high incidence of hemangiosarcomas and mammary gland carcinomas. Swiss mice also developed lung carcinomas after only 6 months of exposure. In all three rodent species an initial 12 month exposure to VC was adequate to detect its carcinogenic potential, but the shortened survival of VC exposed mice and hamsters precluded a meaningful comparison with longer periods of exposure. Exposures were most effective when started early in life.

Age Factors↗
PubMed1983

Chronic effects of dietary exposure to amosite and chrysotile asbestos in Syrian golden hamsters.

Bioassays of amosite, short-range (SR), intermediate-range (IR) or intermediate-range chrysotile asbestos in combination with the intestinal carcinogen 1,2-dimethylhydrazine dihydrochloride (DMH) were conducted with male and female Syrian golden hamsters. Amosite and both forms of chrysotile asbestos were administered at a concentration of 1% in pelleted diet for the entire lifetime of the hamsters starting with mothers of the test animals. Group sizes varied from 125-254. There was no adverse effect on body weight gain or survival by either type of asbestos or by IR chrysotile asbestos in combination with DMH. A significant increase (p less than 0.05) in adrenal cortical tumors was observed in male hamsters exposed to SR and IR chrysotile asbestos and in females treated with IR chrysotile asbestos when compared to the pooled control groups. However, statistical significance (p less than 0.05) was lost when these dosed groups were compared with temporal control groups. Neither of the male or female amosite asbestos groups showed increased neoplasia in any tissue or organ compared to the control groups. The cocarcinogen studies using IR chrysotile asbestos and 1,2-dimethylhydrazine dihydrochloride were considered inadequate because there was no increase in intestinal neoplasia in the DMH group.

1,2-Dimethylhydrazine↗
PubMed1983

Chronic effects of dietary exposure to amosite asbestos and tremolite in F344 rats.

Carcinogenesis bioassays of blocky (nonfibrous) tremolite and amosite asbestos alone or in combination with the intestinal carcinogen 1,2-dimethylhydrazine dihydrochloride (DMH) were conducted with male and female Fischer 344 rats. The minerals were administered at a concentration of 1% in pelleted diet for the entire lifetime of the rats starting with the dams of the test animals. One group of amosite rats also received chrysotile asbestos via gavage during lactation. Group sizes varied from 100 to 250 animals. The offspring from mothers exposed to tremolite or amosite asbestos were smaller at weaning than those from untreated mothers and remained smaller throughout their life. The administration of dimethylhydrazine (DMH) did not affect body weight gain, either in amosite-exposed or nonexposed animals. Survival was comparable in the tremolite and control groups. The amosite-exposed rats showed enhanced survival compared to the untreated controls. DMH exposure reduced survival by approximately one year, although the amosite plus DMH groups survived slightly better than the DMH alone groups. No toxicity or increase in neoplasia was observed in the tremolite-exposed rats compared to the controls. Significant increases (p less than 0.05) in the rates of C-cell carcinomas of the thyroid and monocytic (mononuclear cell) leukemia in male rats were observed in amosite-exposed groups. However, the biological significance of the C-cell carcinomas in relation to amosite asbestos exposure is discounted because of a lack of significance when C-cell adenomas and carcinomas were combined and the positive effect was not observed in the amosite plus preweaning gavage group. The biological significance of an increased incidence of mononuclear cell leukemia is questionable, because of a lack of statistical significance in the amosite group when evaluated using life table analysis, lack of significance when compared to the tremolite control group, and the fact that no toxic or neoplastic lesions were observed in the target organs, i.e., gastrointestinal tract and mesothelium. DMH caused a high rate of (62-74%) of intestinal neoplasia in amosite and nonamosite-exposed groups. Neither an enhanced carcinogenic nor protective effect was demonstrated by exposure to amosite asbestos.

1,2-Dimethylhydrazine↗
PubMed1983

Influence of various purified interferons on effects of drugs in mice.

Direct determinations indicate that some types of interferon increase the duration of hexobarbital-induced sleep time and decrease acetaminophen toxicity. Pretreatment of mice with cloned human leukocyte interferon subtype A, IFN-alpha A, did not increase hexobarbital sleep time but pretreatment with mouse interferon or a hybrid human leukocyte interferon, IFN-alpha AD (Bgl), increased the duration of the effect of the barbiturate. Hybrid IFN-alpha AD (Bgl) also decreased the lethality of acetaminophen. These findings are predictable based on reports of hepatic cytochrome P450 depression resulting from treatment with some interferons.

Acetaminophen↗
PubMed1982

Teratogenicity of a commercial xylene mixture in the mouse.

Pregnant outbred albino (CD-1) mice received (gavage, three times a day in cottonseed oil) a xylene mixture (60.2% m-xylene, 9.1% o-xylene, 13.6% p-xylene, and 17.0% ethyl benzene) on d 6-15 of gestation (d 1 being the day vaginal plugs were observed). The mice were killed on d 18, the general and reproductive health of the dams evaluated, and the fetuses examined and processed to characterize external, visceral, and skeletal malformation. At 3.6 ml/kg.d, xylene killed 12 of 38 dams and caused a significantly (p less than 0.05) smaller average weight gain during pregnancy than did the vehicle (cottonseed oil). Fetuses from dams treated with xylene at 2.4 ml/kg.d and higher doses had average fetal weights significantly lower than that of the control fetuses. However, the percent of resorptions for xylene was significantly greater than for the control only at 3.6 ml/kg-d. At 2.4, 3.0, and 3.6 ml/kg-d xylene produced a significantly (p less than 0.01) greater average percent of malformed fetuses than did the control. Cleft palate was the major malformation at all three doses. When bilateral (multiple) wavy ribs were counted as a malformation, the average percent of malformed fetuses increased from 7.8 to 10.5 at 3.0 ml/kg.d and from 9.1 to 13.4 at 3.6 ml/kg.d. It is concluded that xylene (mixed isomers) is teratogenic to the CD-1 mouse at 2.4 and 3.0 ml/kg.d, doses approaching lethal levels.

Animals↗
PubMed1982

Identification of factors of affective meaning in four selected activities.

The premise that activities have inherent meanings is basic to the theory and practice of occupational therapy. In this study the investigators hypothesized that different activities would elicit different kinds of affective meanings in their participants. The subjects in this study were 59 students beginning their training in occupational therapy. On their first day in an activities class, and before instruction in activity analysis, the subjects were presented with four selected activities. Immediately after performing each activity, the students were requested to rate the activity according to Osgood's 12-scale short-form semantic differential. The data generated were reduced subsequently to Osgood's three factors of affective meaning: "evaluation," power," and "activity" (in this study called action). Results indicated that the four activities elicited significantly different responses on all three factors. Specific results and implications of this study's methodology for future occupational therapy research are discussed.

Adult↗
PubMed1982

Subchronic dietary exposure of rats to chlordecone (Kepone) modifies levels of hypothalamic beta-endorphin.

Rats were exposed for extended times to low doses of chlordecone (1 and 6 ppm in the diet). After 105 days of exposure of female rats to this diet, levels of circulating prolactin and growth hormone were not significantly altered, but at the higher dose of chlordecone, hypothalamic beta-endorphin levels were selectively reduced. Since no changes were seen in pituitary levels of beta-endorphin of treated rats, chlordecone had some regional specificity. Levels of dopamine, serotonin, and their metabolites were unchanged in the caudate nucleus of female rats exposed to chlordecone. Thus, low levels of chlordecone appear to selectively affect hypothalamic beta-endorphin suggesting the hypothalamus may be especially sensitive to this neurotoxicant. The gestationally and lactationally-exposed female offspring of these rats showed a major increase in the levels of growth hormone at 100 days of age. However, other parameters assayed remained unaltered. These consisted of biogenic amines within the caudate nucleus, pituitary and hypothalamic met-enkephalin and circulating prolactin, growth hormone, and estrogen.

Animals↗
PubMed1981

The influence of malnutrition on the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in rats.

A single oral dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (20 or 40 microgram/kg body wt) administered to rats resulted in reduced body weight gain, water intake, degenerative changes in the liver and involution of the thymus. Although a restricted diet alone caused thymic involutions it was shown that TCDD at 10 or 20 microgram/kg body wt accentuated this atrophy. Microscopically, a marked atrophy of the thymus and swelling and necrosis of the liver were found in the malnourished animals. The effects of TCDD were also tested in rats fed either 3.5%, 26% or 55% protein. There was no clear relation between the protein level and the influence of TCDD on the thymus. However, the effect of TCDD on body weight and the liver was more severe in rats given low protein diet. These effects were not reversed by high protein diet. Since it is unlikely that the influence of TCDD on the thymus is related to malnutrition, other mechanisms, such as depletion of energy reserves, a direct effect of TCDD on the thymus or a mediation by the hepatotoxic action may be involved.

Animals↗
PubMed1981

Comparative study of 3,4,3',4'-tetrachlorobiphenyl in male and female rats and female monkeys.

3,4,3',4'-Tetrachlorobiphenyl (TCB) is thought to be the most toxic chlorinated biphenyl present in commercial polychlorinated biphenyl (PCB) formulations. A comparative study of the distribution and excretion of TCB has been done in made and female rats and female rhesus monkeys in an effort to account for the toxicity of this PCB. The distribution and clearance of TCB were similar in male and female rats, and although TCB was cleared more slowly by monkeys than by rats, the monkeys were able to clear it at an appreciable rate so that tissue levels were negligible 6 wk after TCB administration. The results indicate that the toxicity of TCB cannot be attributed to inability of the animals to metabolize and excrete it or to its persistence in any tissue, with the possible exception of blood. TCB and/or TCB metabolites appear to be more persistent in blood than any PCB studied to date.

Animals↗