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Biomedical subjects

B Collins

Publications and source records attributed to B Collins.

At least 73 records · Page 4Linked to original sources
PubMed1988

Natural occurrence of black-pigmented Bacteroides species in the gingival crevice of the squirrel monkey.

The objective of this study was to determine whether the squirrel monkey (Saimiri scuireus) is indigenously colonized with black-pigmented bacteroides (BPB) resembling human Bacteroides gingivalis and Bacteroides intermedius (suspected periodontal pathogens) and to determine the usefulness of the squirrel monkey as an in vivo model for studying colonization by putative pathogens. We assayed the subgingival plaques of 138 monkeys of various ages and in four different colonies for the presence of anaerobic BPB microorganisms. We also tested half the animals for the presence of Actinobacillus actinomycetemcomitans. Clinical indices and levels of serum antibody to B. gingivalis were recorded. We detected BPB in 50% of the animals and A. actinomycetemcomitans in 69% of the animals. The presence of BPB was generally associated with increased age, increased gingival index, presence of calculus, and increased levels of serum antibody. These data indicate that the squirrel monkey may be a good model for studying the parameters of natural infection of the gingival crevice with suspected periodontopathogenic BPB microorganisms.

Age Factors↗
PubMed1987

Tarsal coalitions. A new surgical procedure.

Coalition is a congenital fusion of two or more tarsal bones. Symptoms, if present, usually begin in early adolescence. The typical symptom complexes are aching pain in the rearfoot exacerbated by activity, progression of the flatfoot deformity, decreased tarsal motion, and sometimes peroneal spasm. When patients are asymptomatic, no treatment is necessary. If symptoms begin, the individual should be treated conservatively. If that fails, surgical intervention should be undertaken. Calcaneonavicular coalitions respond well to excision with extensor digitorum brevis interposition. Talocalcaneal middle facet coalitions have responded well to resection with implant arthroplasty. When degenerative changes are present in the subtalar and midtarsal joints, triple arthrodesis is still the procedure of choice.

Biomechanical Phenomena↗
PubMed1986

Effects of 1,1-dichloro-2,2-bis[p-chlorophenyl]ethylene (DDE) on lactation in rats.

An inverse correlation between the concentration of DDE in human breast milk samples and the duration of breast feeding prompted the present study of the effects of DDE administration on the lactational performance of primiparous rats. Daily doses of 10 mg p,p'-DDE/kg body weight were given to virgin female Sprague-Dawley rats 5 d/wk for 5 wk prior to mating and continued throughout the gestation and lactation periods. Lactation capacity was determined by monitoring neonatal growth and by measuring milk production, milk composition (total protein, total lipid, and lactose), and mammary-gland weight and nucleic acid content on d 9 and 20 postpartum. Gross toxicity was assessed by monitoring clinical signs and body weight of the dams, and by measuring organ weights of the dams on lactation d 9 and 20. Histopathological evaluation of the mammary glands and selected organs in the dams and pups was also performed. The dose level of DDE employed was apparently not toxic to the dams and did not have a pronounced effect on neonatal mortality. No significant differences between DDE-treated and control groups were observed for any of the lactation parameters, even though the concentration of DDE in the milk of treated rats was approximately two orders of magnitude greater than the upper range of the DDE levels measured in human milk samples. These findings indicate that DDE does not adversely affect lactation or neonatal growth in Sprague-Dawley rats at the dose level used in this study.

Animals↗
PubMed1986

Absorber hazard.

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Anesthesiology↗
PubMed1986

The prevalence of health risks in an employed population.

To optimize use of the limited resources of the Tennessee State Employee Health Service, health risk and abnormality rates were tabulated for employees screened in the multiphasic screening program in 1983. Histories and health questionnaires revealed many more preventable or correctable health risks and abnormalities than did laboratory or physiologic tests or physical examinations. No previously unknown abnormalities were located by physical examination alone. The authors conclude that health history, risk appraisal, and counseling may be the most productive elements of a preventive screening program for employed groups, as well as for the general population.

Adult↗
PubMed1985

The College I know.

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Societies, Nursing↗
PubMed1983

Serologic and immunopathologic findings in temporal arteritis.

In 104 patients undergoing biopsies for temporal arteritis, lymphocyte characterization identified both T4 helper/inducer and T8 cytotoxic/suppressor lymphocytes in approximately equal numbers. B lymphocytes were absent. Deposition of IgM and IgG was observed in three of 16 positive biopsy specimens. Antinuclear antibodies were present in ten of 16 biopsy-proven cases of temporal arteritis compared with 19 of 55 in the control group with negative biopsy specimens. Anti-smooth-muscle, anti-DNA, and antimitochondrial antibodies were not useful in distinguishing between the two groups.

Antibodies, Antinuclear↗
PubMed1982

Toxicological procedures for assessing the carcinogenic potential of agricultural chemicals.

Pesticides and other agricultural chemicals are now widely used throughout the world as a means of improving crop yields in order to meet the increasing demands being placed upon the global food supply. In Canada, the use of such chemicals is controlled through government regulations established jointly by the Department of Agriculture and the Department of National Health & Welfare. Such regulations require a detailed evaluation of the toxicological characteristics of the chemical prior to its being cleared for use. In this paper, procedures for assessing the carcinogenic potential of agricultural and other chemicals are discussed. Consideration is given to both the classical long-term in vivo carcinogen bioassay in rodent or other species and the more recently developed short-term in vitro tests based on genetic alterations in bacterial and other test systems.

Animals↗
PubMed1982

Syntheses and adrenergic agonist properties of ring-fluorinated isoproterenols.

2-Fluoro-, 5-fluoro-, and 6-fluoroisoproterenol were synthesized by reduction of the Schiff base formed between the corresponding ring-fluorinated 3,4-bis(benzyloxy)phenethanolamine and acetone, followed by reductive debenzylation in the presence of oxalic acid to yield crystalline neutral oxalates. The apparent beta-adrenergic potencies were determined in the isolated guinea pig atria. 2-Fluoro- and 5-fluoroisoproterenol were equipotent with (+/-)-isoproterenol, while 6-fluoroisoprotenol was virtually inactive. No alpha-adrenergic agonist activity (guinea pig aorta) was shown by any of the fluoroisoproterenols. Displacement of alpha- and beta-specific radioligands from isolated membrane preparations from rat brain by the fluoroisoproterenols were in agreement with the responses of the organ preparations. Thus, the apparent fluorine-induced specificity is due to specificity at the receptor binding site. The effects of fluorine substitution are discussed with regard to the apparent negative influence of the 6-fluoro substituent on the beta-agonist properties of isoproterenol, the lack of any increase in potency due to the 2-fluoro substituent, and the possibility of fluorine-induced changes in the electron density of the aromatic ring as a possible rational for the fluorine-induced specificity of both the fluoroisoproterenols and the fluoronoirepinephrines.

Adrenergic alpha-Agonists↗
PubMed1979

Reversal by testosterone of atrophy of accessory genital glands of castrated male sheep. A histologic and morphometric study.

The histologic features of male accessory genital glands of entire sheep (group I), castrated sheep (group II), castrated sheep treated with 40 daily intramuscular injections of 50 milligrams testosterone propionate (group III), and castrated sheep treated with 600 milligrams testosterone propionate 72 hours before death (group IV) were compared. Sheep were castrated at 3 months old and all sheep were killed when 15 months old. Volume fractions of glandular tissue, intralobular fibromuscular tissue and perilobular fibromuscular tissue of the seminal vesicles and Cowper's glands fluctuated significantly (P less than 0.05) during postcastration atrophy and after repeated testosterone treatment. Atrophy in sheep in group II was least in the prostate but greatest in Cowper's glands, seminal vesicles and ampullae of vasa deferentia. Seminal vesicle plexi, whose cytons had a statistically significant (P less than 0.05) degree of shrinkage, also were atrophied. After treatment with testosterone the postcastration atrophy of plexal neurons was almost reversed in sheep in group III. There also was hypertrophy of epithelial cells but the testosterone treatment failed to reduce to normal the fibromuscular volume fraction of the accessory genital glands. Testosterone propionate treatment of sheep in group IV failed to elicit appreciable morphologic changes. These results are compared with our previous findings on the content and uptake of zinc by the accessory genital glands. It is suggested that accumulation of zinc in the accessory genital glands of sheep is not necessarily closely linked to normal histologic appearance.

Animals↗
PubMed1979

Reducing auditory feedback and the acquisition of motor response timing.

Three groups of subjects (n=10) attempted to move a lever 50 cm along a track in 1.50 sec under one of three auditory feedback conditions: Fully augmented increasing auditory feedback (FAF) in which a constant level of velocity-related auditory feedback was provided for all 25 learning trials, reducing auditory feedback (FAF) in which the level of feedback was progressively reduced over the learning trials, and no auditory feedback (NAF). All subjects performed 10 trials with no auditory feedback after a 10-min rest interval. The hypothesis that acquisition of the criterion task would be facilitated under RAF compared to FAF derived partial support. It was concluded that there is sufficient evidence to justify further investigation of reducing auditory feedback as a technique of motor skill acquisition.

Auditory Perception↗
PubMed1977

Hexachlorobenzene residues and effects on esterase activities in pre-weanling rats after a reciprocal transfer between HCB-treated and control dams.

Female Wistar rats were divided into two groups. One group was fed ad libitum powdered rat chow containing 80 ppm hexachlorobenzene (HCB) and the other was fed HCB-free diet 2 weeks before mating until the termination of the experiment. Immediately after parturition, the pups were randomly culled to 10 per litter and 5 pups were reciprocally transferred between HCB and control dams. All pups within same paired litters were sacrificed on the 16th to 17th day and on the 20th to 23rd day after birth. Liver esterase activity toward indophenyl, thiophenyl, and p-nitrophenyl acetates was determined. The liver to body weight ratio, liver esterase activity and HCB residues were significantly higher in pups nursed by HCB-fed dams than in those nursed by control dams. The HCB residue in the liver, kidney, spleen, heart and brain was analyzed by gas-liquid chromatography. At about the weaning time, the HCB residue levels in pups transferred after parturition from HCB fed to control dams were similar to those in pups which remained with the control dams. The results demonstrated that HCB in tissues at about weaning time was obtained largely through milk. In addition, transmission of HCB through milk had greater effects on esterase activities in suckling pups than placental transmission. The pups born to HCB-treated dams and nursed by the control dams were similar to the pups born and nursed by the same control dams.

Animals↗