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Biomedical subjects

C Bowman

Publications and source records attributed to C Bowman.

At least 19 recordsLinked to original sources
PubMed1990

The effects of immersion and exercise on prolactin during pregnancy.

Prolactin is an important hormone during pregnancy, affecting mother, fetus, and amniotic fluid volume. Immersion is known to affect prolactin levels significantly. To determine the effect of immersion and exercise on the prolactin response during pregnancy, we examined serum prolactin levels at 15, 25, and 35 weeks' gestation and 10 weeks post partum. Twelve women completed 20 min land rest, 20 min immersion in 30 degrees C water to the xiphoid, and 20 min exercise in the water at 60% VO2max. Resting prolactin levels were 1.91 +/- 0.32, 4.55 +/- 0.5, and 5.85 +/- 0.27 nmol.l-1 +/- standard error of the mean at 15, 25, and 35 weeks' gestation, respectively. Postpartum lactating women had a resting mean prolactin level of 3.95 +/- 1.6 versus 0.22 +/- 0.4 nmol.l-1 in non-lactating women. Prolactin levels declined significantly during immersion even after correction for dilution by plasma volume shifts. The immersion response was inversely related to the duration of pregnancy with 29%, 22%, and 12% drops during 15-, 25- and 35-week trials, respectively. Compared to rest, exercise prolactin levels remained depressed during the 15th and 25th week trials. We hypothesize that immersion in water caused prolactin levels to decline.

Adult↗
PubMed1990

Renal responses to immersion and exercise in pregnancy.

Twelve healthy pregnant women were studied at 15, 25, and 35 weeks' gestation and at 8 to 12 weeks postpartum. Women were immersed for 20 minutes at 30 degrees C. They then exercised at 60% maximum oxygen capacity on a modified ergometer. Substantial diuresis and natriuresis occurred without changes in osmolarity or serum sodium. The diuresis was significantly greater during pregnancy than postpartum. The natriuresis was similar. Diuresis and natriuresis were greater than would be expected from investigations in nonpregnant subjects. This study suggests that immersion may be a beneficial therapy for edema without decreasing plasma volume.

Diuresis↗
PubMed1990

Kinetics and pathogenicity of autoantibodies induced by mercuric chloride in the brown Norway rat.

Repeated low-dose injections of mercuric chloride (HgCl2) in the brown Norway (BN) rat result in polyclonal activation which includes the induction of anti-glomerular basement membrane (GBM) autoantibodies. We examined the kinetics of various autoantibodies produced in vivo, general features of polyclonal activation such as total IgG levels and immune complex formation, and the relationship between organ specific autoimmunity and tissue injury in the kidney and thyroid. The production of immune complexes and autoantibodies to GBM and thyroglobulin was short lived, and the increase in levels of total IgG and antibodies to ssDNA and dsDNA was prolonged; the antibody response to collagen types I and II was intermediate in duration. Autoantibodies induced by HgCl2 caused only mild and variable tissue injury in the kidneys and did not induce abnormalities in the thyroid. These studies demonstrate that immunostimulation by mercury may result in the formation of a range of autoantibodies, with variable kinetics and pathogenicity.

Animals↗
PubMed1988

Transfacial resection of intracranial tumor.

Tumors of the skull base with intracranial and extracranial components pose special access problems. Traditional craniotomy and extensive external incisions produce morbidity that can be avoided in properly selected cases. Current surgical techniques extend previously described operations to allow good visualization and safe resection through the face for certain intracranial tumors. Meticulous attention to surgical techniques and wide exposure for complete tumor visualization are essential to ensure the safety of these procedures.

Adolescent↗
PubMed1987

The effect of endotoxin on peripheral blood lymphocytes in the rat.

We have studied the effects on peripheral blood lymphocytes of the administration to rats of a single dose of endotoxin. Lymphopenia occurred during the first hour, and persisted during 24 hours. Lymphocyte subpopulations were examined by flow cytometry. T-lymphocytes were relatively resistant to the initial effects of endotoxin, but there were no differences in the responses of cells identified as T-helper or T-suppressor/cytotoxic lymphocytes. The effects of endotoxin on peripheral blood lymphocytes is less extreme but appears more persistent than the effects on granulocytes.

Animals↗
PubMed1987

Circulating T-cell populations during mercuric chloride-induced nephritis in the Brown Norway rat.

Fluorescence-activated cell sorter analysis was used to study the peripheral lymphocyte populations during mercuric chloride (HgCl2)-induced autoimmune nephritis in the Brown Norway (BN) rat. Sequential studies showed a transient loss of T cells from peripheral blood attributable to decreases in the percentage of T-helper cells. In addition, there was a decrease in the percentage of T-cytotoxic/suppressor cells prior to the appearance of circulating anti-GBM antibodies, followed by elevated levels of T-suppressor cells during down-regulation of the response. This method may allow closer inspection of the events linking changes in T-cell populations and induction and termination of an autoimmune response.

Animals↗
PubMed1987

Restriction of human IgG subclass expression in the population of auto-antibodies to glomerular basement membrane.

To study the possible relationship between individual subclass expression and pathogenesis of antibody-mediated disease, we examined the immunoglobulin-G subclass of antiglomerular basement membrane (GBM) antibodies, in the sera of 20 patients with auto-antibody mediated nephritis, as well as in a limited number of kidney eluates, using a solid phase radioimmunoassay and monoclonal antibodies specific for human IgG subclasses. Only anti-GBM antibodies of the IgG1 and/or IgG4 subclass were detectable, both in the circulation and in renal eluates. Recurrence of circulating anti-GBM antibody during convalescence occurred in two patients out of 49 studied sequentially for more than 12 months. In both cases only antibodies of a single subclass were involved. The recurrence of IgG1 antibody (which can fix complement and bind macrophages) was associated with clinical manifestations of disease, whereas the reappearance of IgG4 antibody (which cannot engage amplifiers of the inflammatory response) did not appear to be harmful. Thus, in anti-GBM auto-antibody mediated nephritis, clear restriction in the subclass of IgG auto-antibody occurs, and this may be important in disease expression.

Autoantibodies↗
PubMed1986

Antiglomerular basement membrane antibody mediated disease in the British Isles 1980-4.

Clinical and pathological data on 71 patients from throughout the British Isles who developed antiglomerular basement membrane antibody mediated nephritis in the period 1980-4 were studied. Two principle patterns of disease were recognised: young men presenting in their 20s with Goodpasture's syndrome (glomerulonephritis and lung haemorrhage) and women presenting in their 60s with glomerulonephritis alone. The effect of treatment on prognosis of a total of 108 patients was also reviewed (the 71 patients plus patients seen before 1980 at Hammersmith Hospital). Treatment with prednisolone, cytotoxic drugs, and plasma exchange hastened the time to clearance of autoantibody and improved the outlook of patients who were not dependent on dialysis and those with lung haemorrhage.

Adolescent↗
PubMed1985

The reduction in the peritonitis rate among high-risk CAPD patients with the use of the Oreopoulos-Zellerman connector.

We have described a prospective controlled study of the Oreopoulos-Zellerman peritoneal dialysis connection system which is based on the principle of chemical sterilization of the connector between each dialysis exchange. This system, in a short-term study of 27 high-risk patients, has resulted in a fourfold difference in the peritonitis rate between the concurrent control group (1/8.8 patient months) and the O-Z group (1/35.7 patient months). The probability of developing peritonitis by 6 mos was 0.15 using the O-Z connector and 0.46 in the control group.

Adult↗
PubMed1985

Clinical application of a radio-immunoassay for auto-antibodies to glomerular basement membrane.

We describe a sensitive radio-immunoassay for auto-antibodies to glomerular basement membrane (GBM). The assay discriminates patients with glomerulonephritis associated with circulating auto-antibodies to glomerular basement membrane from those with other forms of nephritis. Monitoring of antibody levels in sequential serial serum samples enables drug therapy to be tailored precisely to control the aberrant immune response, a situation unique in the management of glomerulonephritis.

Autoantibodies↗
PubMed1979

Cation transport and membrane potential properties of primary astroglial cultures from neonatal rat brains.

This paper describes K+ and Na+ content and transport in primary monolayer cultures from dissociated newborn rat brains, considered to consist predominantly of astroglial cells. Net changes in cation content after addition of ouabain, and steady state fluxes using 86Rb+ as a marker for K+ and 22Na+ as a marker for Na+, were measured. The results found indicate that the cells maintained a conventional pattern of cation homeostasis with net efflux of K+ being balanced by its active uptake and net uptake of Na+ balanced by active extrusion mediated by a ouabain sensitive (Na+K) pump. These processes maintained internal measured K+:Na+ ratios of 12--25:1. The cells were normally flat but addition of DBcAMP caused them to round up and form numerous processes, an appearance resembling that of astroglial cells in vivo. DBcAMP treatment also reduced the steady state levels of K+ measured with 86Rb+ by 15--30%, and had no effect on initial rates of 86Rb+ and 22Na+ uptake. The membrane potentials of cells treated with DBcAMP were studied, since only these were easily impaled. The membrane potentials of separate groups of cells gave means ranging from --65 to --75 mV at 35 degrees C, at an external K+ concentration ([K+]o) of 4.5 mM. The dependence of the membrane potentials of individual cells and groups of cells on [K+]o was studied. The slope of the potential per 10-fold change in [K+]o was 55--57 mV, at concentrations of K+ greater than 10--20 mM K+, and diverged from this slope at concentrations below this. This shows that these cells had some permeability to ions other than K+. Assuming that Na+ was the only other ion affecting the membrane potential, it was calculated that the permeability to Na+ was about 30 times less than K+. A similar result was obtained based on estimates of Na+ and K+ permeability from transport experiments on cells also treated with DBcAMP. The results obtained from these cells are compared to those found for other cultured glial cells and glial cells in vivo. We conclude that the membrane potentials of the cultured cells used in the present study show the closest resemblance so far to glia in vivo, since they are large and negative and are determined mainly by K+. However, the cultured cells have different properties from those reported in some studies for glial cells in vivo by showing free permeability to ions other than K+.

Animals↗
PubMedDate not supplied

Parotid salivary secretion in diabetic autonomic neuropathy.

Parotid salivary flow rates and amylase concentrations were measured in three groups of eight subjects each (normal control, non-neuropathic diabetic, and neuropathic diabetic). Flow rates were significantly reduced in neuropathic diabetic patients as compared with normal controls (p less than 0.001) and non-neuropathic diabetic patients (p less than 0.02). Amylase concentrations were similar. These data are consistent with parasympathetic denervation of the parotid gland in diabetic neuropathy and provide evidence for a widespread distribution of autonomic denervation in diabetes.

Adult↗