PubMed Health⌕ Search

Biomedical subjects

J C Rivera

Publications and source records attributed to J C Rivera.

9 recordsLinked to original sources
PubMed2001

A comparison of 0.5% ropivacaine and 1% mepivacaine for sciatic nerve block in the popliteal fossa.

BACKGROUND: The purpose of this study was to compare anesthetic efficacy and postoperative analgesia of 0.5% ropivacaine and 1% mepivacaine for sciatic nerve block in the popliteal fossa (popliteal block). METHODS: A prospective, double-blind study was carried out in 58 adult patients scheduled for outpatient foot or ankle surgery. They were randomized to receive popliteal block with 40 ml of either 0.5% ropivacaine (group R) or 1% mepivacaine (group M). An atraumatic, Teflon-coated needle connected to a neurostimulator was used to make a single puncture using a posterior approach. The times to onset of sensory and motor block, and the need for intraoperative sedation were recorded. Before discharge, patients were asked to document the time to first analgesic use, time to return of full sensation in the foot, and their evaluation of the technique. RESULTS: Onset time (mean+/-standard deviation, 95% confidence interval) of both sensory block (6.5+/-5.1 min, 4.47-8.49, in group R and 6.2+/-3.7 min, 4.83-7.69, in group M) and motor block (6.6+/-4.4 min, 4.81-8.23, in group R and 7.9+/-4.1 min, 6.29-9.53, in group M) was similar in both groups. Postoperative analgesia lasted longer in group R (15.2+/-5.1 h, 13.25-17.21) than in group M (5.7+/-1.8 h, 5.01-6.41; P<0.001). Duration of sensory block was longer in group R (20.7+/-6.2 h, 18.51-23.01) than in group M (6.5+/-1.7 h, 5.86-7.16; P<0.001). Acceptance of the anesthetic procedure was similar in both groups. CONCLUSION: In this study we demonstrated that both 0.5% ropivacaine and 1% mepivacaine for popliteal block produced rapid, effective and safe anesthesia but postoperative analgesia was more long-lasting with ropivacaine.

Adult↗
PubMed2001

Expression of prolactin gene and secretion of prolactin by rat retinal capillary endothelial cells.

PURPOSE: Prolactin fragments inhibit blood vessel formation, whereas anti-prolactin antibodies induce angiogenesis in the cornea. Endothelial cells from brain capillaries and the umbilical vein produce prolactin, and this study was undertaken to determine whether retinal capillary endothelial cells could be a source for prolactin in the eye. METHODS: Primary cultures of rat retinal endothelial cells were investigated for the expression of prolactin mRNA by reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot analysis and by in situ hybridization. The prolactin protein was analyzed by immunocytochemistry, enzyme-linked immunoabsorbent assay, Western blot analysis, and the Nb2-cell bioassay. The effect of prolactin and the 16-kDa prolactin fragment on retinal endothelial cell proliferation was investigated, and the expression of the cloned prolactin receptor was analyzed by RT-PCR and Southern blot analysis. RESULTS: Retinal endothelial cells expressed prolactin mRNA and full-length 23-kDa prolactin. Prolactin was observed in the cytoplasm of cells and in their conditioned medium at levels 300 times those described in endothelial cells from other vessels and species. Exogenous 16-kDa prolactin inhibited rat retinal endothelial cell proliferation, whereas 23-kDa prolactin was inactive. No evidence was obtained for the expression of the cloned prolactin receptor in these cells, but the prolactin receptor was amplified in whole rat retina. CONCLUSIONS: Endothelial cells from the microcirculation of rat retina produce and release prolactin. That the cloned prolactin receptor was not expressed in these cells argues against direct autocrine effects of prolactin. Possible paracrine effects are suggested by the expression of the prolactin receptor in retinal tissue.

Animals↗
PubMed1988

Liver function testing in a working population: three strategies to reduce false-positive results.

A very high rate of mildly abnormal results on a liver panel of five serum chemistries was observed when these tests were performed on a group of asymptomatic, normal workers. These results often led to lengthy delays in hiring, which benefited neither worker nor employer. Three strategies which markedly reduce the number of false-positive examinations with little or no reduction in test sensitivity are available.

False Positive Reactions↗
PubMed1986

Occupational allergy to laboratory animals: an epidemiologic study.

A cross-sectional study has been carried out at The National Institutes of Health to examine the prevalence of laboratory animal allergy (LAA) in a population exposed to animals, and to compare the prevalence of general allergy in the exposed v a control group. A group of 289 workers with light-to-moderate exposure to animals, 260 with heavy exposure, and 242 control subjects were interviewed. A slightly greater prevalence of general allergy was found among those working with laboratory animals (39%), than in the control group (33.9%), but the difference was not statistically significant. The prevalence of LAA in the total exposed group was 23.9%. A history of atopic problems and history of allergy to domestic animals correlated significantly with LAA, as did the number of species of animals handled and the average number of hours per week exposed to laboratory animals, with evidence of dose-response relationships.

Animals↗
PubMed1984

The National Institutes of Health animal handlers medical surveillance program.

The medical surveillance program for animal caretakers, technicians, and other personnel having contact with animals at the National Institutes of Health is described. The program classifies workers according to the groups of animals with which they work. It includes preplacement physical examinations, preventive immunizations, testing, and monitoring of health status. This program helps to protect the workers' health from diseases acquired from animals and to prevent ill employees from adversely affecting the health of the animals with which they work.

Animals↗
PubMedDate not supplied

Allergy to laboratory animals in health care personnel.

Lab animal allergy is a frequent affliction of health care and research personnel whose work involves contact with lab animals. It affects up to 30% of those who are exposed directly and even some workers exposed indirectly, often unwittingly. The consequences of LAA may be severe, including disabling asthma and loss or attenuation of a career. Although recognized for many years, the working-out of the fine details about animals antigens, extracts, and diagnosis and treatment regimens is still far from finished. Not one prospective study longer than one year has been reported, although at least three are underway. It is hoped that information from these studies will contribute to the knowledge about the true incidence of LAA, exposure dose-response, and sensitivity, specificity, and positive predictive value of possible contributory factors such as atopy. The consesus of opinion is that, until the full significance of possible predictive factors is known, judgments concerning employment based on these factors should be avoided. Finally, there is a great need for increased emphasis on the development and objective evaluation of preventive measures.

Animals↗