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Biomedical subjects

R W Moore

Publications and source records attributed to R W Moore.

At least 73 records · Page 4Linked to original sources
PubMed1986

Thyroid status and thermogenesis in rats treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin.

Several key aspects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxicity resemble the effects of hypothyroidism, while in other ways the toxic responses are characteristics of hyperthyroidism. Whether thyroid dysfunction plays a role in TCDD toxicity remained unknown, however. We therefore determined the dose-related effects of TCDD treatment on plasma concentrations of L-thyroxine (T4), 3,5,3'-triiodo-L-thyronine (T3), and thyroid-stimulating hormone (TSH), and compared these changes with signs of TCDD toxicity. We also determined whether indices of functional thyroid status (and thermogenesis) were altered in response to TCDD treatment. Young adult male Sprague-Dawley rats were given single oral doses of TCDD (6.25-100 micrograms/kg) and evaluated 1 week later. Toxicity, measured by decreases in feed intake and body weight, ranged from minimal to severe. Plasma concentrations of T4 were greatly reduced at all doses tested, while T3 was increased in a dose-related fashion (up to 35%). TSH was elevated but was inversely proportional to dose. Thyroid histology was unremarkable, and TCCD treatment had little effect on the ability of rats to raise serum T4, T3, and TSH concentrations in response to acute cold stress. TCDD treatment caused a slight (8%) decrease in basal metabolic rate, yet comparable decreases were seen in pair-fed control animals. Thermogenesis, as measured by O2 consumption and colonic temperatures in rats exposed to various ambient temperatures, was only marginally affected. In summary, although thyroid hormone concentrations were markedly altered, rats given doses of TCDD sufficient to cause overt toxicity appeared to be essentially euthyroid. These results do not support proposals by other researchers that altered thyroid status is a major contributor to TCDD toxicity and/or a key response to TCDD exposure.

Animals↗
PubMed1986

Impact of a rural high blood pressure control program on hypertension control and cardiovascular disease mortality.

Kentucky is a predominantly rural state with relatively high death rates from hypertension and cardiovascular disease. We report the results of a community-based high blood pressure control educational program undertaken in two rural counties of southeastern Kentucky. In the intervention counties, systolic and diastolic blood pressures of both men and women decreased despite the five-year increase in age; moreover, hypertension was better controlled after the program, and substantial decreases in deaths due to cardiovascular disease were seen. These differences were greater among men in the two regions than among women. The results of this program suggest that, in sparsely populated rural areas, existing resources and programs can be successfully utilized in a communitywide cardiovascular disease risk reduction educational program.

Adolescent↗
PubMed1985

Androgenic deficiency in male rats treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin.

Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the male reproductive system were investigated. Sexually mature (290 g) Sprague-Dawley rats were given single oral doses of TCDD sufficient to cause varying degrees of hypophagia and impaired body weight gain. The largest doses decreased plasma testosterone and dihydrotestosterone concentrations by 90 and 75%, respectively, from ad libitum-fed control values, while decreasing seminal vesicle and ventral prostate weights by 68 and 48%. On Day 7, the approximate ED50 for these responses was 15 micrograms TCDD/kg, a nonlethal dose. Reductions in caput epididymis and testis weights were also observed. The androgenic deficiency was seen as early as 2 days after dosing and persisted for at least 12 days. Based on data from pair-fed control rats, only about half the decreases in accessory sex organ weights and in plasma androgen concentrations could be accounted for by TCDD-induced hypophagia or body weight loss. These signs of androgenic deficiency were not the result of stress (based in part on plasma corticosterone assays), nor could they be accounted for by the known effects of TCDD on steroid metabolism. While the TCDD-induced depression in plasma testosterone concentrations appears to be the primary event observed, the mechanism by which testosterone concentrations were decreased remains unknown. The androgenic deficiency may account for the male reproductive pathology and dysfunction in animals treated with overtly toxic doses of TCDD.

Androgens↗
PubMed1985

A comparison of electro-ejaculation with the artificial vagina for ram semen collection.

Nine fertile three-year-old Romney rams were ejaculated both by means of electro-ejaculation and by the artificial vagina. The ram repeatabilities of semen volume, concentration, total sperm number, percentage normal sperm and wave motion score of ejaculates collected by electro-ejaculation were 0.17, 0.08, 0.12, 0.61 and 0.23 respectively compared with the repeatabilities of ejaculates collected by the artificial vagina of 0.28,0.79, 0.56,0.72 and 0.54. The repeatability results showed that it was possible to rank rams on the quantity of sperm produced in a single ejaculate obtained by an artificial vagina, but not on the quantity obtained by electro-ejaculation. The correlation co-efficients between the ram means for the two techniques were for volume 0.05, concentration 0.06, total sperm number -0.21, percentage normal sperm 0.73, and wave motion score 0.35. Only the percentage normal sperm coefficient was significant.

Journal Article↗
PubMed1985

Relationship between carcass composition and first oestrus in Romney ewe lambs.

Weaned Romney ewe lambs were grazed at two levels of nutrition from 20 December to 12 April. Both groups were grazed together at a high level of nutrition thereafter. Vasectomized rams were introduced on 1 April. Oestrus occurred in 62/84 (74%) of the low nutrition group and in all 24 of the high nutrition group. The mean date of first oestrus was 3 June for the former and 28 May for the latter. The non-oestrous ewes were killed on 17 July and the others within 5 days of showing oestrus. From each carcass, certain organs (i.e. adrenals, ovaries, thyroid, heart, kidneys, liver, lungs, spleen, stomach and uterus) and various fat depots were dissected out and weighed. In addition, half of the carcass was minced and subsampled for protein and fat analysis. The weight of uterus discriminated between oestrous and non-oestrous animals, as did a linear combination of the weights of lungs, spleen and stomach. The data suggest that fatness or protein content, or the weights of the other organs, are not important indicators of sexual maturity in female sheep.

Animal Nutritional Physiological Phenomena↗
PubMed1984

Glucose-dependent lactate production by homogenates of neuronal tissues prepared from rats treated with 2,4-dithiobiuret, acrylamide, p-bromophenylacetylurea and 2,5-hexanedione.

Chronic treatment of rats with dithiobiuret (DTB) produces a delayed onset muscle weakness and, as suggested by a preliminary study, a distal axonopathy. An inhibition of glycolysis resulting in an energy deficit has been suggested as a possible mechanism of neurotoxin-induced distal axonopathies. To determine whether chronic DTB administration (1 mg/kg/day X 7 days; sacrificed on Day 7) might be associated with a perturbation of glucose metabolism in neuronal tissues, lactate production was measured in brain and spinal cord homogenates prepared from rats which exhibited hindlimb skeletal muscle weakness. Kinetic and statistical analysis showed that glucose-dependent lactate production in these homogenates was not different from that of controls. Lactate production was also determined in brain homogenates prepared from rats intoxicated with acrylamide (50 mg/kg/day X 9 days; sacrificed on Day 9), p-bromophenylacetylurea (200 mg/kg/day X 2 days; sacrificed on Day 14) or 2,5-hexanedione (400 mg/kg/day X 21 days; sacrificed on Day 21). The results indicated that whereas 2,5-hexanedione produced a slight decrease in Vmax, acrylamide and p-bromophenylacetylurea did not cause changes in glucose-dependent lactate production. These findings do not support the suggestion that an inhibition of glycolysis represents a common biochemical lesion associated with neurotoxins which cause delayed onset muscle weakness and distal axonopathy.

Acrylamide↗
PubMed1983

Enzymatic determination of oxalates.

An assay for oxalate, based on oxalate oxidase, was studied. It is relatively simple, rapid and reproducible and may be semi-automated and is accurate in the range 10-140 mg/l, has a coefficient of variation of 4.2% in the healthy range (10-19 mg/l serum). Samples may be stored at -20 degrees C for as long as 2 weeks. It cannot be used for the determination of urinary oxalate because of the presence of variable amounts of low molecular weight inhibitor(s).

Autoanalysis↗
PubMed1983

Enhancement of carrageenan and dextran-induced edemas by 2,3,7,8-tetrachlorodibenzo-p-dioxin and related compounds.

Paw edema formation after the subplantar injection of carrageenan was enhanced in rats treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The enhanced carrageenan response could be detected as early as 4.5 hr after TCDD; however, the magnitude of enhancement was greatest when rats were challenged with carrageenan 5 days after TCDD. In the latter case, the ED50 of TCDD in enhancing the carrageenan response was 6 micrograms/kg. TCDD also enhanced dextran-induced paw edema, which follows a time course different from that of carrageenan-induced edema and is produced by a different mechanism. The enhancement of carrageenan and dextran paw edemas was due to an increase in the edema-producing potency of the irritants and not to a change in their maximum effect. The ability of other 3-methylcholanthene-type inducers to enhance carrageenan-induced paw edema and the inability of phenobarbital-type inducers to cause the response suggest that the TCDD binding protein might be involved in edema enhancement. TCDD also enhanced carrageenan-induced pleural edema; however, the number and type of leukocytes recovered in the pleural exudate was not affected. TCDD did not alter granuloma formation produced by the subcutaneous implantation of cotton pellets, indicating that enhancement by TCDD was peculiar to edema formation and not to inflammation in general. It is suggested that TCDD may enhance carrageenan and dextran edemas by increasing the availability of mediators involved in each type of edema formation and/or by increasing the responsiveness of the vasculature to mediators.

Animals↗
PubMed1982

Acid-base and electrolyte values in dogs with acute gastric dilatation-volvulus.

Twenty dogs with acute gastric dilatation-volvulus (GDV) and 37 clinically normal dogs had arterial blood drawn for analysis of pH and blood gases. There was no statistically significant difference between values from the 2 groups. By calculation of the anion gap and by assessing arterial bicarbonate concentration, it appeared there were concomitant and offsetting factors, resulting in normal values for pH, blood gases, and anion gap in dogs with GDV. The results obtained indicated that sodium bicarbonate therapy should not be used in dogs with GDV.

Acidosis↗
PubMed1982

Behavioral preparation of patients for gastrointestinal endoscopy: information, relaxation, and coping style.

The effectiveness of two techniques for preparing patients to undergo a stressful medical examination was assessed using observer self-report, and physiological measures of distress during gastrointestinal endoscopy. Patients were either informed about expected sensations, trained in systematic muscle relaxation, or received normal hospital procedures. The influence of coping styles on the effectiveness of information and relaxation techniques was examined for measures of fear, avoidance, emotional control, arousability, and independence. Information and relaxation interventions reduced heart rate increases and observer ratings of distress during tube insertion. Relaxation training also increased positive mood change following the procedure. Interactions between coping styles and recovery measures suggested patients benefited most from preparation that matched their preferred coping style, but were not harmed by preparation that did not match their preferred style. Discussion focuses on how coping styles may interact with preparation procedures and suggests that the use of coping styles as criteria for excluding patients from certain preparation techniques is inappropriate.

Adult↗
PubMed1981

On the perceived meaning of symptoms.

The importance of understanding the manner in which symptoms are interpreted is generally recognized, but has received relatively little direct research attention. In an attempt to obtain some evidence on the meaning attached to each of a set of 45 symptoms, subjects were asked to rate the symptoms on eight semantic properties. The symptom ratings on the various properties were then correlated and the correlation matrix subjected to a principal components factor analysis. Three factors of perceived meaning emerged. The first factor is defined by the extent to which symptoms are perceived as threatening, disruptive and painful. The second factor consists of the familiarity of symptoms and the perceived personal responsibility for their occurrence. The third factor reflects how embarrassing the symptoms are. This structure of perceived meaning of symptoms is discussed with reference to the literature on delay in seeking medical care.

Decision Making↗
PubMed1981

Promoting effects of polychlorinated biphenyls (Aroclor 1254) and polychlorinated dibenzofuran-free Aroclor 1254 on diethylnitrosamine-induced tumorigenesis in the rat.

The hepatic tumor-promoting activity of a commercial polychlorinated biphenyl mixture, Aroclor 1254 (AR 1254), with and without its intrinsic polychlorinated dibenzofuran (PCDF) impurities, was investigated. Male Sprague-Dawley non-inbred albino rats were treated with 66 microgram diethylnitrosamine (DENA)/ml drinking water for 5 weeks and subsequently given a control diet or a diet supplemented (100 ppm for 18 wk) with either AR 1254 or AR 1254 from which the PCDF moieties were removed (AR 1254-PCDF). Of those animals receiving DENA alone, 16% exhibited hepatocellular carcinomas. Of those rats treated with DENA followed by administration of AR 1254 or AR 1254-PCDF, 64 or 84%, respectively, developed hepatocellular carcinomas. Thus promotion with either AR 1254 or AR 1254-PCDF significantly (P less than 0.05) increased the incidence of DENA-initiated hepatocellular carcinomas. Administration of AR 1254 or AR 1254-PCDF alone did not induce hepatic tumors. Therefore, PCDF impurities were not necessary for the promoting activity of AR 1254.

Animals↗
PubMed1980

Fertilizing ability of semen from rams of high- and low-prolificacy flocks.

The difference between fresh undiluted ram semen from high (H) and low (L) prolificacy Romney selection lines in success in fertilizing artificially inseminated Romney, half-Romney and Cheviot ewes (unrelated and randomly allocated) was examined in 3 experiments. For ewes producing natural multiple ovulations, the fertilization rate was 71% (40/56) and 40% (20/50) for semen from H rams and L rams respectively (P < 0.01). Fertilization rates for PMSG-induced multiple-ovulating ewes were 61% (11/18) for H semen and 22% (4/18) for L semen (P > 0.05). Values for single-ovulating ewes were 52% (35/67) for H semen and 50% (28/56) for L semen (P > 0.05).

Animals↗
PubMed1980

Effects of PMSG and the prostaglandin F-2 alpha analogue, cloprostenol, on superovulation, fertilization and egg transport in the ewe.

Romney ewes were artificially inseminated at the oestrus after treatment with PMSG on Day 12 of the cycle, Cloprostenol on Day 14, or both. PMSG resulted in increased numbers of ovulations and large follicles but Cloprostenol had no effect alone or with PMSG, PMSG and Cloprostenol alone led to reduced proportions of eggs fertilized, and PMSG also reduced the proportion of ewes with fertilized eggs. The distribution of eggs in the reproductive tract indicated more rapid egg transport in ewes treated with PMSG. A greater proportion of eggs was recovered from the uterus in ewes in which oestrus was first detected at night. Cloprostenol, as administered to PMSG-treated ewes in this trial, offered no advantage for the preparation of donor ewes for egg transfer.

Animals↗
PubMed1979

Intervals between multiple ovulations in PMSG-treated and untreated ewes and the relationship between ovulation and oestrus.

The timing of ovulations in 42 PMSG-treated ewes was determined by repeated endoscopy. The first ovulation occurred at a median time of 23 . 6 +/- 0 . 5 (s.e.m.) h after the onset of oestrus. The median interval between first and second ovulations was less than 1 h, and that between first and last ovulations was approximately 6 h. In 59 untreated ewes, probit regression analysis was applied to the number of ovulations which were found by endoscopy to have occurred by 23, 25 and 27 h after the onset of oestrus. The median time of first ovulation was 25 . 5 +/- 0 . 5 h after the onset of oestrus, this interval being similar in single- and twin-ovulating ewes. The median interval between twin ovulations was 1 . 2 +/- 0 . 6 h. Ovulation occurred after the end of oestrus in at least 75% of ewes.

Animals↗