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Biomedical subjects

P Collins

Publications and source records attributed to P Collins.

At least 343 records · Page 19Linked to original sources

Transmission of Salmonella mbandaka to cattle from contaminated feed.

Salmonella mbandaka was isolated from cattle on three dairy farms. The duration of infection was less than four weeks and none of the animals became clinically ill. The animals had all consumed a diet containing a vegetable fat supplement contaminated with S. mbandaka and this was shown to be the source of the infections. It is significant that a feed containing purely vegetable components was incriminated.

Animal Feed↗

Hepatic Injury following halothane, enflurane, and isoflurane anesthesia in rats.

Halothane anesthesia administered to enzyme-induced animals in a hypoxic atmosphere consistently produced hepatic necrosis. Rats pretreated with phenobarbital were exposed to hypoxia at varying intervals after administration of halothane, enflurane, or isoflurane anesthesia. Anesthetics were administered at 1 MAC for 2 h. For each agent, hypoxia consisting of 8 per cent oxygen-balance nitrogen for 1 h was imposed at the end of anesthesia. In other groups of rats, we also used a 15-, 30-, 60-, and 120-min interval of 100 per cent oxygen between 2 h of halothane anesthesia and the imposition of hypoxia. Controls included enzyme-induced animals with and without hypoxia, hypoxia alone, and cage controls. Hepatic injury was graded by histologic examination of the livers. Injury was greater when hypoxia followed halothane anesthesia than when it followed enflurane, isoflurane, or enzyme-induction alone. A difference in injury score existed between control animals and those anesthetized with halothane who received a 15-min interval of oxygen before hypoxia. Combined results from the 15- and 30-min delay groups also were different from control. There was no difference between control and halothane groups when the oxygen interval was 60 or 120 min. The injury score of the enflurane and isoflurane groups were comparable to that of controls. We conclude that the potential for hypoxia-induced liver injury during recovery exists after halothane anesthesia. Neither enflurane nor isoflurane anesthesia produced significant hepatic injury in this model.

Anesthetics↗

Postanesthetic hepatic injury in rats: influence of alterations in hepatic blood flow, surgery, and anesthesia time.

Hepatic injury was measured in enzyme-induced rats following ligation of the hepatic artery performed under anesthesia with thiamylal, halothane, enflurane, or isoflurane. The influence of surgical site was determined by performing upper abdominal (sham ligation), lower abdominal, and peripheral surgery on rats anesthetized with halothane. The effect of anesthesia time was evaluated by continuing halothane anesthesia for 1, 2, or 4 hours after upper abdominal (sham ligation) surgery. Centrilobular necrosis did not occur in enzyme-induced rats anesthetized with thiamylal, isoflurane, or enflurane, or in halothane-anesthetized animals that had not undergone enzyme induction. When halothane was the anesthetic, hepatic injury was significant after both the sham operation and ligation of the hepatic artery, and hepatic injury was directly related to anesthesia time. Lower abdominal surgery and the sham operation were associated with comparable hepatic damage, which was more than that occurring after peripheral surgery.

Abdomen↗

Titanium, silver, and tantalum clips in brain tissue.

The brain tissue reaction to a recently devised titanium haemoclip and to the conventional silver and tantalum clips were investigated in rabbit brain. Titanium, silver, and tantalum wires 5 X 0.5 X 0.5 mm in size were implanted into the white matter of the brain. After one and six months the brain specimens were sectioned, stained with haematoxylin eosin and with phosphotungstic acid Haematoxylin, and were studied by light microscopy. The examination revealed neither tissue reaction nor pigmentation in the case of titanium implant, while there was pigmentation surrounding the tantalum, and there was pigmentation as well as reactive gliosis around the silver wires.

Animals↗

The occurrence and significance to animal health of Leptospira, Mycobacterium, Escherichia coli, Brucella abortus and Bacillus anthracis in sewage and sewage sludges.

Samples of sewage, sewage sludge and sewage effluent from one or more of four sewage treatment plants were examined for the presence of Leptospira, Mycobacterium, Escherichia coli, Brucella abortus and Bacillus anthracis. Brucella abortus and Bacillus anthracis were not isolated. Eleven strains of E. coli potentially enteropathogenic for calves or piglets, eight pathogenic strains of Mycobacterium and one patho;genic Leptospira strain were isolated from 101, 189 and 189 samples respectively. Sewage sludge is no;t considered to play a major part in the epidemiology of disease caused by these organisms.

Animal Diseases↗

Minimum alveolar concentrations and oil/gas partition coefficients of four anesthetic isomers.

We determined the minimum alveolar concentration (MAC) of four structural isomers having the empirical formula C3H2F5CIO in dogs. MAC for three of the four isomers (including isoflurane and enflurane) ranged from 1.41 to 2.67 (volumes per cent at one atmosphere pressure). The olive oil/gas partition coefficients at 37 degrees C for these isomers ranged from 90.8 to 96.6. In contrast, MAC for the fourth isomer, compound 485, was 12.53 per cent atm. However, the oil/gas partition coefficient for that compound was 25.8. These results suggest that isomer 485, despite its high MAC, does not deviate strikingly from the established correlation between anesthetic potency and lipid solubility.

Anesthetics↗

Are convulsant gases also anesthetics?

This study investigated whether the convulsant gas flurothyl deviates from the correlation between anesthetic potency and lipid solubility. Flurothyl (CF3CH2OCH2CF3) produced convulsions in 50% of mice at 0.122 +/- 0.006% atm. Mice often convulsed repeatedly after exposure to flurothyl, the maximum number of convulsions occurring when the concentration was 0.24% atm. Concentrations greater than 0.6% atm produced convulsions immediately after addition of flurothyl, but rarely at later times. An ED50 value for loss of the righting reflex was obtained when the concentration was 1.22 +/- 0.19% atm. The oil/gas partition coefficient was found to be 46.9 for flurothyl at 37 C. The product of righting-reflex ED50 and oil/gas partition coefficient (0.0122 atm x 46.9 = 0.57 atm) is similar to that found for conventional anaesthetics in mice. Therefore, flurothyl does not deviate from the correlation of anesthetic potency and lipid solubility. It was also found that 0.3 to 0.8% atm flurothyl increased isoflurane MAC in dogs, but that 3 to 4% atm flurothyl decreased it. The increase of isoflurane requirement at lower concentrations of flurothyl suggests that anesthetics with a potential to cause convulsions may partly antagonize their own anesthetic effect. The decrease in isoflurane MAC in dogs at higher concentrations of flurothyl also implies that this compound has an anesthetic effect. A structural isomer of flurothyl, iso-Indoklon [(CSF3)2CHOCH3], was only anesthetic and did not have convulsant properties. Its MAC in dogs was 4.60 +/- 0.45% atm, and its righting-reflex ED50 in mice was 2.65 +/- 0.13% atm. The product of iso-Indoklon MAC in dogs and its oil/gas partition coefficient (27.0) was 1.24 atm, and the product of iso-Indoklon righting-reflex ED50 in mice and oil/gas partition coefficient was 0.72 atm. These values are close to those found for conventional anesthetic agents in dogs and mice; thus iso-Indoklon also does not deviate from the correlation between anesthetic potency and lipid solubilities.

Anesthesia, Inhalation↗

Survey of knowledge among primary health care workers in diabetes.

The knowledge of diabetes mellitus held by allied health professionals in Kentucky and the short-term and long-term effectiveness of a symposium in altering this knowledge was studied. The groups investigated consisted of: 136 primary health workers (nurses, dieticians, health educators, and other health professionals) surveyed before and after the 12-hour symposium (group 1); 37 of these primary health professionals studied again one year after the first symposium (group 2); and 26 nurses who work at a university hospital, and who did not attend the symposium (group 3). Before training, all groups performed similarly on this survey. Group 1 scored 58.5 +/- 0.2% correct, group 2, 56.9 +/- 3.1% correct, and group 3, 52.7 +/- 5.0% correct. Performance did not correlate with educational level, job description, or geographic location within Kentucky. There was a negative correlation between performance and age for group 1 (r = -0.3494, P < .001). Follow-up studies immediately after the symposium showed that a significant improvement occurred in the performance of group 1 and group 2 on this knowledge survey (correct score +/- SEM = 82.5 +/- 0.3%, and 81.7 +/- 2.4% respectively, P < .005) compared to pretraining scores. A repeat survey of group 2 one year later showed a significant deterioration of knowledge (P < .05), but not to pretraining levels (mean correct score = 69.2 +/- 3.4% at one year versus 56.9 +/- 3.1% before training, P < .02). These results suggest that more emphasis on professional education in diabetes and study of effective methods for providing this education is required.

Adult↗

Reissner's fibre in the rat: a scanning and transmission electron microscope study.

The structure and connexions of Reissner's fibre have been studied in the rat by means of scanning and transmission electron microscopy. The fibre was found to arise from a series of filaments, each of which was formed by a structure forming the juxta-aqueductal surface or lining of the subcommissural organ. This structure was termed 'apical spherical protrusion' and was found to be rich in rough endoplasmic reticulum. The fibre was firmly attached at its rostral end to the subcommissural organ, at its middle to the ventral surface of the termination of the aqueduct and finally to the calamus scriptorius of the fourth ventricle. It was held in a state of considerable tension between these three points and attached to it were numerous cilia from the ependymal lining. In sections examined by TEM the fibre appeared to be totally amorphous in structure, with erythrocytes and other debris attached to it.

Animals↗