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Biomedical subjects

M C Foster

Publications and source records attributed to M C Foster.

At least 19 recordsLinked to original sources
PubMed1992

Effects of serotonin and carbachol on glial and neuronal rubidium uptake in leech CNS.

Effects of serotonin (5-HT) and carbachol on Rb uptake (used as a K marker) in leech neuron and glia were studied by electron probe microanalysis (EPMA). Hirudo medicinalis ganglia were perfused 60 s in 4 mM Rb substituted normal leech Ringer's with and without 5-HT (dosage range 5-500 microM) or carbachol (range 10-1000 microM), quench frozen cryosectioned, and subjected to EPMA to determine elemental mass fractions and cell water content. Both 5-HT and carbachol altered leech neuron and glial cell elemental distribution and water content. In glial cells, a dose-dependent increase in Rb uptake was observed following 5-HT (control: 26 +/- 2 microM; 5 microM: 47 +/- 4; 50 microM: 62 +/- 4; 500 microM: 82 +/- 11 mmol/kg dry wt. +/- S.E.M.) and carbachol (10 microM: 35 +/- 3; 100 microM: 52 +/- 3; 1000 microM: 68 +/- 3 mmol/kg dry wt. +/- S.E.M.). In neurons, 5-HT and carbachol had small effects. 5-HT decreased glial and neuronal cell water content. Carbachol decreased neuronal (but not glial) water content by approximately the same amount (mean decrease 9%) regardless of dose. Both 5-HT and carbachol affected glial cell K-accumulating properties, providing evidence that certain neurotransmitters may modulate invertebrate glial cells' K clearance function.

Animals↗
PubMed1992

Preferential uptake of rubidium from extracellular space by glial cells compared to neurons in leech ganglia.

Glial cells play a significant role in maintaining extracellular space (ECS) potassium (K) by temporarily buffering or accumulating excess ECS K and then returning that K to neurons. Yet, little is known about the relative affinity of neurons or glial cells for K when both cells are simultaneously exposed to the same ECS K, in situ. Also, the process by which glial cells return K to neurons remains unknown. Therefore, electron probe X-ray microanalysis was used to measure rubidium (Rb) uptake, as a K tracer, into leech packet neurons and glial cells, and to measure the distribution of cell water content, K, Na and Cl. When ECS Rb was increased from 4 mM to 20 mM, there was a clear preferential Rb uptake into glial cells compared to neurons. At 4 mM extracellular Rb there was only a small difference between uptake velocity of neurons and glial cells (maximum mean uptake velocity at 4 mM Rb was 1.09 for glia, and 0.41 mmol Rb/kg dry wt/s for neurons), whereas at 20 mM extracellular Rb, glial uptake velocity was dramatically greater than of neurons (max. mean Rb uptake velocity for glia was 4.3 compared to 1.47 mmol Rb/kg dry wt/s for neurons). Glial Rb uptake velocity was enhanced by low temperature (max. mean Rb uptake velocity at 20 mM ECS Rb at 6 degrees C was 6.04 for glia compared to 0.78 mmol Rb/kg dry wt/s for neurons) and by substitution of Cl with isethionate (max. mean Rb uptake velocity was 10.6 for glia compared to 1.33 mmol Rb/kg dry wt/s for neurons).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Personal-computer-based system for electron beam X-ray microanalysis of biological samples.

A system based on a personal computer has been developed which provides a relatively inexpensive way to equip an electron microscopy laboratory for quantitative elemental analyses of cryosectioned biological samples. This system demonstrates the feasibility of making an X-ray analyser from a personal computer, together with commercially available hardware and software components. Hardware and software have been assembled to drive the beam in a scanning electron microscope, collect and analyse X-ray spectra, and save, retrieve, and analyse data. Our software provides a menu-controlled user interface to direct spectra acquisition and analysis. Spot analyses, video images, and quantitative elemental images may be obtained and results transferred in ASCII format to other computers. Wet weight, as well as dry weight, concentrations are calculated, if measurements were made of areas of the hydrated sample before it was freeze-dried. Grey-level copies of video and quantitative elemental images may be made on a laser printer.

Animals↗
PubMed1990

Using self-help support groups: a framework for nursing practice and research.

Social support groups are receiving increased attention in professional literature and the media and the number of groups is growing. Nurses are often urged to utilize social support groups as part of client care. These groups cannot be effectively used by nurses unless they are approached from the framework of the nursing process. This approach helps assure individualization of referrals and evaluation of the support group in relation to the client's needs. Based on the literature reviewed and the proposed nursing process framework, many research questions are identified.

Humans↗
PubMed1990

Health visitors as educators.

This paper describes some models of health education as a context for considering data from a recent study of mothers' and health visitors' perspectives on good child health care. Most health visitors favoured an individualistic top-down approach aimed at changing mothers' behaviour. Mothers preferred a dialogue which started from their own priorities.

Adult↗
PubMed1990

Carcinoma of the prostate masquerading as rectal carcinoma. Report of 3 cases and review of the literature.

We present 3 patients with prostatic tumours who presented with symptoms of rectal stenosis. In all 3 cases digital examination of the rectum revealed a mass suggestive of rectal carcinoma, but carcinoma of the prostate was suspected because of other clinical features and this was confirmed by biopsy. Treatment by hormonal manipulation resulted in a dramatic improvement in symptoms. The diagnostic and management difficulties associated with this unusual presentation of carcinoma of the prostate are described, together with a review of the literature.

Adenocarcinoma↗
PubMed1990

Characteristics of cadaveric renal allograft recipients developing chronic rejection.

As the early results of renal transplantation improve, chronic rejection is increasing in relative importance as a cause of graft loss. The aetiology of the condition is unknown. In order to identify possible predisposing factors, the characteristics of 22 patients with chronic rejection were compared with those of 50 patients with stable graft function 2 years or more after transplantation. Patients with chronic rejection had significantly more acute rejection episodes in the first 6 months after transplant (P less than 0.01), a higher incidence of acute rejection with vascular features (P less than 0.01), and longer ischaemic times (P less than 0.05) compared to patients with stable graft function. In a logistic regression analysis both frequency and severity of acute rejection episodes were significantly associated with the subsequent development of chronic rejection. Thus chronic rejection is associated with early injury to the transplanted kidney.

Adult↗
PubMed1989

The increasing importance of chronic rejection as a cause of renal allograft failure.

A consequence of reducing early graft failure due to acute rejection has been that more patients are at risk of chronic rejection, something which has become an increasingly important cause of graft loss. We examine the graft survival rates and reasons for failure in our unit from 1981 to 1986. Patients were divided into two series according to treatment of acute rejection episodes. From 1983 onwards, by treating acute vascular (poor prognosis) episodes with antilymphocyte globulin (ALG), we have significantly improved the 6-month actuarial graft survival rate. However, the percentage of total graft failure due to chronic rejection in this second series has significantly increased. The need for greater understanding of the aetiology of chronic rejection, together with its present unsatisfactory treatment, is discussed.

Adult↗
PubMed1989

Early experience of the gittes "no-incision" pubovaginal suspension for stress urinary incontinence.

A series of 20 women with stress urinary incontinence underwent bladder neck suspension according to the method in which there are no suprapubic or vaginal incisions and no buttresses. Follow-up was between 9 weeks and 8 months. Twelve patients (60%) were cured, 2 (10%) were significantly improved and 6 (30%) were not improved; 3 patients had pre-operative detrusor instability; when they were excluded the failure rate fell to 23%. These results are inferior to those obtained in this unit using the Stamey procedure, although the difference is not significant. The operation is quick and easy to perform and was well tolerated with minimal complications; we believe it is worthy of further evaluation.

Adult↗
PubMed1989

The late results of renal transplantation and the importance of chronic rejection as a cause of graft loss.

The results of 279 renal transplants performed in a single centre between 1974 and 1986 are reviewed. Improvements in the management of acute rejection and a reduction in mortality have resulted in an improvement in 1-year actuarial graft survival rates from 44% for transplants performed before 1980 to 68% for those performed after 1983. After the second year post-transplant there has been a steady rate of graft failure (6% per annum), mainly due to chronic rejection. In total 52 grafts have developed chronic rejection (19% of the total and 30% of those at risk at 6 months). Chronic rejection is assuming greater relative importance as a cause of graft loss as early results improve.

Adult↗
PubMed1988

Use of older patients as cadaveric kidney donors.

We have no fixed upper age limit for cadaveric kidney donors and donors over the age of 50 provided kidneys for 22 per cent of our adult transplant recipients between 1983 and 1986. Immediate function following transplantation occurred in 17 per cent of these kidneys compared with 58 per cent for kidneys from donors under the age of 50. The 1-year actuarial graft survival rate for transplants from donors over 50 was 52 per cent, compared with 70 per cent for transplants from donors under 50 (P less than 0.05). Thus kidneys from older donors make an important contribution to the total pool of organs available for transplantation, but their use leads to inferior results in comparison with kidneys from younger donors.

Adolescent↗
PubMed1987

Perioperative prophylaxis with sulbactam and ampicillin compared with metronidazole and cefotaxime in the prevention of wound infection in children undergoing appendectomy.

Sulbactam is a beta-lactamase inhibitor, which when administered with ampicillin, increases the latter agents antibacterial activity against beta-lactamase producing organisms. One hundred children between the ages of 5 and 14 undergoing emergency appendectomy were entered into a prospective randomized trial comparing sulbactam and ampicillin (SA) with metronidazole and cefotaxime (MC) as prophylaxis against postoperative wound infection. Patients in whom the appendix was perforated or gangrenous received a 72-hour course of antibiotics, others received a single dose only. The overall wound infection rate was 8% (14% in patients with perforation or gangrene and 4% in those without). There was no difference in infection rate between the two antibiotic groups; there were three wound infections and one subphrenic abscess in patients receiving SA and four wound infections in patients receiving MC. SA, therefore, appears to be a suitable antibiotic combination for use as prophylaxis in appendicitis in children.

Adolescent↗
PubMed1986

Serial effects on left ventricular load and contractility during hemodialysis in patients with concentric hypertrophy.

To separate the effects of hemodialysis on loading conditions from those on contractile state, six patients with concentric left ventricular hypertrophy and normal left ventricular function were studied before, during, and after hemodialysis. Two-dimensional-directed M-mode ultrasound was used to measure left ventricular dimensions and wall thickness; a sphygmomanometer and carotid pulse recording were used to determine peak and end-systolic blood pressure. From these data, meridional stress at end systole was calculated and stress-dimension and stress-shortening relations were derived; measurements of metabolic parameters were made simultaneously. Heart rate and systolic blood pressure were stable throughout dialysis. Reductions in left ventricular dimensions and increased shortening were evident by 30 minutes of dialysis and were largely complete by mid-dialysis. These changes coincided with a decrease in potassium and an increase in ionized calcium but not in pH, which changed only in the latter half of dialysis. When stress-dimension and stress-shortening relations were examined, both individual and group data for all coordinates before, during, and after dialysis demonstrated an excellent linear fit consistent with a single contractile state. We conclude that in stable patients with left ventricular hypertrophy, the reduction in heart size and improvement in shortening are due primarily to reductions in preload and afterload.

Blood Pressure↗