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Biomedical subjects

J Reynolds

Publications and source records attributed to J Reynolds.

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

Differentiation of B lymphocytes in sheep. I. Phenotypic analysis of ileal Peyer's patch cells and the demonstration of a precursor population for sIg+ cells in the ileal Peyer's patches.

The ileal Peyer's patches (IPP) of sheep may be a primary lymphoid organ for b cells since they have a number of important features in common with the bursa of Fabricius of chickens. We have examined the surface phenotype of IPP cells. Approximately 90% to 95% of IPP cells are 'low sIgM+'; that is, they have surface IgM, but in much smaller amounts than peripheral B cells, which are 'high sIgM+'. IPP cells with sIgG or sIgA are very rare. Upon exposure to a tumour promotor, phorbol myristate acetate (PMA), in vitro, low sIgM+ cells differentiated into high sIgM+ cells. The amount of Ia-like antigens on the surface also increased after PMA treatment. Approximately 5% of IPP cells bore no identifiable markers. However, these cells could also be induced into high sIgM+ cells upon exposure to PMA; this may indicate the presence of precursors of sIgM+ cells within the IPP. While PNA (peanut agglutinin) binds strongly to the vast majority of IPP cells, it binds very little, if at all, to B cells obtained from the periphery, unless they have been treated with neuraminidase; this suggests that cells in the B lineage retain their PNA receptors, but that these become masked by sialic acid on mature B cells.

Animals↗
PubMed1982

Noninvasive assessment of changes in myocardial perfusion and ventricular performance following exercise training.

Seventeen coronary patients (CAD) underwent thallium (TI-201) treadmill and radionuclide (RNV) ejection fraction supine bicycle testing before and after 5.6 +/- 1.6 (mean +/- SD) months of an exercise program. Thallium data were assessed both using analog images and a computerized circumferential profile technique. Patients exercised on the treadmill to a higher workload after the exercise program, but achieved a similar pressure-rate product. When interpreting the analog thallium images, only 50% agreement was obtained for the assessment of changes in myocardial perfusion (pre/post-training). The computer technique, however, had low inter-intraobserver variability (6%) and better agreement (90.5%). Using the circumferential profile method, five patients improved (a total of 11 regions) and one patient worsened (with two regions). Before the exercise program, the ejection fraction (EF) response to supine bike exercise was normal (an increase greater than 11%) in four, flat in seven, and severely abnormal (a decrease of more than 4%) in six patients. After the exercise program, even though achieving similar or higher pressure-rate products, six patients improved their EF response, nine did not change, and two worsened. Of the five patients who improved their thallium images, one improved his EF response, two remained normal, and two did not change. One patient worsened both his thallium study and the EF response after the exercise program. Changes in thallium exercise images and the EF response to supine exercise occurred in our patients after an exercise program, but were not always concordant. Indeed, of five patients with exercise-induced ischemic ST changes before and after training, the EF response improved in three whereas myocardial perfusion was unchanged. Reasons for this lack of agreement are discussed, and have been considered in the planning of a randomized trial of the effects of an exercise program on myocardial perfusion and function.

Adult↗
PubMed1982

Piperacillin and gentamicin v carbenicillin and gentamicin for treatment of serious gram-negative infections.

Piperacillin sodium, a new penicillin with remarkable in vitro activity against Pseudomonas aeruginosa and other Gram-negative bacilli, and gentamicin sulfate were compared with carbenicillin disodium and gentamicin in a prospective, randomized, double-blind comparison for treating serious Gram-negative infections. Of the 32 patients whose courses were "evaluable" for efficacy, 12 of 14 who received piperacillin and gentamicin and 13 of 18 who received carbenicillin and gentamicin had favorable outcomes. Of the 99 patients whose courses were evaluable for toxicity, nine of 51 recipients of piperacillin and gentamicin and 15 of 48 recipients of carbenicillin and gentamicin suffered clinical reactions possibly, probably, or definitely related to the penicillin. No statistically significant differences were found in the two groups in the frequencies of biochemical abnormalities, including hypokalemia, that occurred in 19 or 44 recipients of piperacillin and gentamicin and 16 of 45 recipients of carbenicillin and gentamicin. Thus, this study did not prove differences in efficacy of toxicity for piperacillin and gentamicin plus carbenicillin and gentamicin for serious Gram-negative infections.

Bacterial Infections↗
PubMed1982

T-cell recirculation in the sheep: migratory properties of cells from lymph nodes.

T lymphocytes derived from different sources in sheep were compared for their ability to recirculate from blood to lymph. Nylon wool columns were used to prepare T-cell-enriched populations from efferent intestinal lymph, efferent prescapular lymph and from cell suspensions of mesenteric lymph nodes and prescapular lymph nodes. With each animal, T cells from two of the above sources were labelled in vitro, one population with fluorescein isothiocyanate the other with rhodamine isothiocyanate; both populations were returned to the animal at the same time by intravenous injection. The intestinal lymph and prescapular lymph were continuously monitored to compare the recirculating properties of the two populations of T cells. This technique led to confirmation of the earlier reports in sheep of a preferential recovery of intestinal lymph T cells and of prescapular lymph T cells in the lymph from which the cells were originally collected. This phenomenon was much less evident with T cells from mesenteric nodes and prescapular nodes and in a number of experiments a random pattern of recirculation occurred. It is concluded that there are differences in the composition of the T-cell population in a node compared with that of the lymph draining the node. The advantages of using fluorescently-labelled cells to study lymphocyte migration are discussed.

Animals↗
PubMed1981

Latex agglutination inhibition card test for gentamicin assay: clinical evaluation and comparison with radioimmunoassay and bioassay.

Gentamicin levels were determined in 100 serum specimens by a new latex agglutination inhibition card test, a radioimmunoassay (RIA), and a bioassay. Correlation coefficients determined by linear regression analysis demonstrated that the levels obtained by the latex agglutination inhibition card test had a high degree of correlation with the RIA and could be performed much faster and more economically when processing small numbers of specimens. The bioassay had a slightly lower degree of correlation with both the RIA and the latex test and was adversely influenced by concurrently administered antibiotics which could not be eliminated by beta-lactamase. When measuring gentamicin concentrations above 2 micrograms/ml, the coefficient of variation was less than 14% for the latex agglutination assay compared with 15% for the bioassay and 12% for RIA. The latex agglutination inhibition card test is a rapid, accurate, specific, and reproducible method for monitoring gentamicin levels in patients and is particularly applicable for laboratories processing small numbers of specimens.

Animals↗
PubMed1981

The effect of search time on perception.

A group of 100 carefully selected chest radiographs was read by ten observers, five experienced and five inexperienced. The radiographs were chosen to present the readers with a disproportionately large number of both subtle abnormalities and nonpulmonary lesions. Each reader was allowed to search the radiographs for as long as appropriate, up to a maximum of four minutes. The length of time taken for each observation was recorded to the nearest second. The time-perception data were plotted on both linear and semilogarithmic graphs. The results showed that experienced readers concluded their visual search while positive detection rate was higher than the rate for false-positives. For lesions in the central phasic, with both a rapid and a slow component of perception. If these data are plotted on a semilogarithmic scale, each of the two components plots as a straight line. For lesions in the periphery of the radiograph (chest wall and upper abdomen), the time-perception curve is monophasic, showing only a slow component.

False Negative Reactions↗
PubMed1980

Studies of the transport of polyclonal IgA antibody from blood to bile in rats.

Bile or thoracic duct lymph, collected from rats 7-9 days after suspensions of B. abortus, S. typhi or SRBC had been injected into the Peyer's patches, contained high titres of specific agglutinins. Samples of these fluids were injected i.v. into unimmunized, syngeneic recipients and the partitioning between blood and bile of the injected antibodies was studied and found to depend on the source and class of the antibody. IgA antibodies from lymph plasma disappeared rapidly from the recipients' blood and half of the dose was recovered in the bile within 2 h of its injection. IgA antibodies which had been collected from bile and so had previously traversed the liver and acquired secretory component, appeared in the recipients' bile much less rapidly so that less than half of the dose entered the bile over a period of 40 h. Passively administered IgG antibodies did not enter the recipients' bile to any significant extent and specific haemolysins never appeared in the bile after either passive or active immunization.

Agglutinins↗