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Biomedical subjects

J Gibson

Publications and source records attributed to J Gibson.

At least 253 records · Page 14Linked to original sources
PubMed1987

Clonal analysis of autoreactive B cells in a murine model of autoimmune hemolytic anemia.

Hybridoma technology was used to examine the repertoire of autoantibody producing B cells in mice with autoimmune hemolytic anemia induced by injection of rat red blood cells (RBC). The results point to the importance of suppressor T cells (Ts) in both the induction as well as the maintenance of the self-specific B-cell repertoire at the clonal level. Thus when normal BALB/c mice were immunized to provoke a high autoantibody response, the hybrids generated were mainly (97%) cross-reactive with mouse RBC, whereas after immunization to elicit Ts and a low autoantibody response, hybrids were mainly (87%) rat RBC specific. In addition, when hybrids were generated from rat RBC immunized (CBA X B10A)F1 mice, in which Ts levels had been depleted during ontogeny, hybrids with "forbidden" purely anti-self (mouse RBC) specificity were detected.

Anemia, Hemolytic↗
PubMed1987

Ammonium and methylammonium transport in Rhodobacter sphaeroides.

Rhodobacter sphaeroides maintained intracellular ammonium pools of 1.1 to 2.6 mM during growth in several fixed nitrogen sources as well as during diazotrophic growth. Addition of 0.15 mM NH4+ to washed, nitrogen-free cell suspensions was followed by linear uptake of NH4+ from the medium and transient formation of intracellular pools of 0.9 to 1.5 mM NH4+. Transport of NH4+ was shown to be independent of assimilation by glutamine synthetase because intracellular pools of over 1 mM represented NH4+ concentration gradients of at least 100-fold across the cytoplasmic membrane. Ammonium pools of over 1 mM were also found in non-growing cell suspensions in nitrogen-free medium after glutamine synthetase was inhibited with methionine sulfoximine. In NH4+-free cell suspensions, methylammonium (14CH3NH3+) was taken up rapidly, and intracellular concentrations of 0.4 to 0.5 mM were maintained. The 14CH3NH3+ pool was not affected by methionine sulfoximine. Unlike NH4+ uptake, 14CH3NH3+ uptake in nitrogen-free cell suspensions was repressed by growth in NH4+. These results suggest that R. sphaeroides may produce an NH4+-specific transport system in addition to the NH4+/14CH3NH3+ transporter. This second transporter is able to produce normal-size NH4+ pools but has very little affinity for 14CH3NH3+ and is not repressed by growth in high concentrations of NH4+.

Biological Transport↗
PubMed1987

Chronic lymphocytic leukaemia complicated by recurrent Bell's palsy.

A patient who presented with a transient right-sided Bell's palsy (lower motor neurone lesion of the facial nerve) and chronic lymphocytic leukaemia (CLL) is described. During the following 5 years whilst receiving intermittent treatment for her CLL, the patient experienced two further episodes of Bell's palsy, one on the right side and the other left-sided. Each episode completely resolved. This is the first reported case of recurrent Bell's palsy complicating CLL.

Facial Paralysis↗
PubMed1987

Felodipine versus prazosin as an addition to a beta-blocker in the treatment of essential hypertension. The Australian Multicentre Study.

The efficacy and tolerability of felodipine and prazosin were compared in a double-blind randomised parallel group study of 100 patients with moderately severe essential hypertension, treated concomitantly with a beta-blocking drug. After a 2- to 8-week run in phase (beta-blocking drug plus placebo), patients with a diastolic blood pressure greater than or equal to 95mm Hg were randomly given felodipine (n = 50) or prazosin (n = 50). After an initial dose of either felodipine 2.5mg bid or prazosin 0.5mg bid for 3 days, the drugs were titrated at 2-week intervals (felodipine 5, 10, 20mg bid, prazosin 1, 2, 4mg bid) if the supine diastolic blood pressure was greater than or equal to 90mm Hg. Treatment was continued for 8 weeks. Baseline supine blood pressures of each group were similar (177/104mm Hg, felodipine; 176/103mm Hg, prazosin). At week 6, supine blood pressures in the felodipine group were 144/82mm Hg and 161/90 in the prazosin group. The reductions in systolic and diastolic blood pressures were significantly greater for the felodipine group than the prazosin group in both the supine and standing positions at all visits after baseline. At 8 weeks, supine diastolic blood pressure less than 90mm Hg was achieved in more patients in the felodipine (36/47) than in the prazosin group (20/43, p less than 0.01). The total number of adverse reactions was similar in both groups. During active therapy, a greater number of patients experienced vascular adverse reactions (oedema and flushing) with felodipine (23) than with prazosin (12). Most events were mild and did not necessitate withdrawal from therapy. There were no clinically significant changes in laboratory variables in either treatment group. Felodipine was an effective, well tolerated hypotensive agent when used concomitantly with a beta-blocking drug. In the doses used it was more effective than prazosin at reducing blood pressure.

Adrenergic beta-Antagonists↗
PubMed1987

Association between Km1 immunoglobulin allotype and pulmonary tuberculosis in Indonesians.

Allotypes were determined in 121 cases of smear-positive pulmonary tuberculosis and 33 healthy controls from Indonesia. It was found that the occurrence of Km1 was significantly lower in patients than in controls (p = 0.011), and that phenotypes lacking G1m (17) and G3m(21) as well as Km1 occurred much more frequently among patients than controls (p = 0.0025). Some evidence for an allotypic influence on the antibody response to mycobacterial antigens was found. A lack of G1m(17) or G3m(21) was associated with increased antibody levels in the IgG2 subclass in control subjects and a lack of Km1 with decreased antibody levels in the IgG4 subclass in patients.

Antibodies, Bacterial↗
PubMed1986

Potentiation of hybridoma production by the use of mouse fibroblast conditioned media.

L-CM is a conditioned medium prepared from cultures of L-929 cells, a murine fibroblast line. It will promote the growth and antibody secretion of B cell hybridomas after fusion as well as facilitating cloning at limit dilution and the growth of cloned B cell lines in bulk culture. The medium is easy to prepare and stores well at 4 degrees C. It thus provides a convenient alternative to the use of feeder cells in the production of monoclonal antibodies.

Animals↗
PubMed1986

Drug-resistant tuberculosis in Sierra Leone.

Culture and sensitivity tests were performed on tubercle bacilli from patients with tuberculosis attending a provincial general hospital in Sierra Leone, who appeared clinically to have drug-resistant infections. Amongst the general intake of patients from 1978 to 1984 there was a 10.5% incidence of isoniazid resistance, with 7.7% of patients having strains resistant to both streptomycin and isoniazid, 1.3% resistant to rifampicin, and 0.8% resistant to ethambutol. Multiple drug resistance was more frequent than single drug resistance. This high incidence is largely due to inadequate and irregular supplies of first line drugs.

Antitubercular Agents↗
PubMed1986

I.v. sedation for conservative dentistry. A comparison of midazolam and diazepam.

Midazolam and the emulsion formulation of diazepam were compared in a cross-over study in 50 patients undergoing out-patient conservative dentistry, with particular regard to sedation and the quality of recovery. Both agents proved effective, but sedation was achieved more rapidly with midazolam (P = 0.001) and was more effective (P less than 0.02). Significantly greater anterograde amnesia for the dental procedure (P less than 0.001) and a more rapid return to normal activities (P less than 0.02) were found with midazolam. Psychometric testing, however, failed to show any objective differences between the treatments. A mean dose of midazolam 0.14 mg kg-1 was required to achieve sedation equating to 0.29 mg kg-1 of diazepam, although there was considerable variation between individual patients.

Adolescent↗
PubMed1986

Management of splenectomy failures in chronic immune thrombocytopenic purpura: role of accessory splenectomy.

Accessory splenic tissue was demonstrated in four of eight patients with chronic immune thrombocytopenic purpura investigated following post-splenectomy relapses. Time from initial splenectomy to relapse of thrombocytopenia ranged from immediately to eight years and post-splenectomy changes were present on the peripheral blood films of all patients at time of relapse. Three scanning techniques were employed to demonstrate and localise residual splenic tissue. Conventional 99mTc scans were positive in three of the four patients whilst 99mTc-heat damaged red cell scans and computerised tomographic scans were each positive in three out of three patients including the one patient in whom a conventional 99mTc scan was negative. Histological confirmation of splenic tissue was obtained in all cases with the weights of the accessory spleens ranging from 0.6 g to 2 g. Two patients responded to accessory splenectomy and, without immunosuppressive therapy, have remained well with normal platelet counts for over four years. There was no correlation between length of initial remission and the response to removal of the accessory spleen. The presence of a functioning accessory spleen should be considered in all patients with chronic ITP who fail to respond to, or relapse following, initial splenectomy.

Adult↗
PubMed1986

Uptake of benzoate by Rhodopseudomonas palustris grown anaerobically in light.

The uptake and anaerobic metabolism of benzoate were studied in short-term experiments with phototrophic cells of Rhodopseudomonas palustris. Cells that were preincubated and assayed anaerobically in the presence of 1 mM dithiothreitol accumulated [7-14C]benzoate at a rate of at least 0.5 nmol . min-1 . mg-1 of protein. Cells that were preincubated aerobically, or anaerobically in the absence of a reducing agent or an electron donor such as succinate, took up benzoate at reduced rates. Benzoate was removed from the external medium with remarkably high efficiency; initial uptake rates were independent of substrate concentration, and uptake remained linear down to concentrations of less than 1 microM. Uptake rates were not sensitive to external pH in the range of 6.5 to 8.1, and very little free benzoate was found associated with the cells. By contrast, benzoyl coenzyme A (CoA) was formed rapidly in cells exposed to labeled benzoate. Its appearance in such cells, together with the more gradual accumulation of other compounds tentatively identified as reduction products, is consistent with the identification of benzoyl CoA as an intermediate in the anaerobic reductive metabolism of benzoate. The very effective uptake of external benzoate can be explained by its conversion to benzoyl CoA immediately after its passage across the cell membrane by simple or facilitated diffusion. Such a chemical conversion would serve to maintain a downhill concentration gradient between the cell cytoplasm and the cell surroundings, even at very low external benzoate concentrations.

Acyl Coenzyme A↗
PubMed1986

Medical imaging of fetal ventriculomegaly.

Five cases of fetal ventriculomegaly are described in detail. Following ultrasonography, either computerized tomography or magnetic resonance imaging was used in an attempt to clarify the structural pathology of the ventriculomegaly. In two patients, a precise diagnosis was achieved while a probable diagnosis was established in a third patient. The diverse etiology of fetal ventriculomegaly in these five cases demonstrates that ancillary medical imaging may be necessary to achieve diagnostic precision prior to therapeutic intervention.

Adult↗
PubMed1985

Outpatient intravenous antibiotic therapy. Ten years' experience.

The experience within the past ten years at Methodist Hospital and Park Nicollet Medical Center, Minneapolis, has clearly demonstrated that outpatient intravenous (IV) antibiotic therapy can be undertaken with relative ease and results in substantial cost savings. During this time, no significant morbidity and no mortality associated with this modality have occurred. Patients of all ages with bone, joint, skin, or soft-tissue infection and other infectious diseases such as meningitis have participated. Patient compliance and enthusiasm have been high. Necessary elements for such a program include an enthusiastic medical staff, a central admixture service, and a team of nurses or other health care professionals available for IV cannula care. Careful patient selection, education, and follow-up are also essential. We believe use of outpatient IV antibiotic therapy will continue to grow in the future, in part because of changes in the financing of medical care.

Ambulatory Care↗