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Biomedical subjects

J C Mason

Publications and source records attributed to J C Mason.

At least 73 records · Page 4Linked to original sources
PubMed1980

Medical students and psychiatric patients: an encounter of the first kind.

The use of psychiatric patients in teaching interview techniques to inexperienced medical students is a common practice. This report describes the impact of this training as assessed through questionnaire analysis of 35 patients and 32 medical students involved in an interview course for second-year medical students. The experience was viewed by both patients and students as useful, and more students reported it as being stressful than did patients. Patients valued it because they thought it would improve medical education, while students found it personally helpful. Most patients (94 percent) and all students indicated they would participate in a similar experience. Most patients felt that the students understood them well in contrast to the student's perception of not understanding the patient.

Attitude to Health↗
PubMed1979

Starvation-induced changes in secretin-like immunoreactivity of human plasma.

Levels of secretin-like immunoreactivity in the plasma of 50 starved subjects were measured by radioimmunoassay and rose from 18 +/- 3 (S.E.) pg/ml after 12 h, to 103 +/- 12 pg/ml (P less than 0.005) after 36 h. The assay antibodies were found to be specific for a region of secretin located towards the C-terminal residue. Lactoperoxidase was used to label the secretin with 125I and ionexchange chromatography on SP-Sephadex C-25 was used to purify the labelled product. The plasma immunoreactivity was purified by immunoaffinity chromatography on antibody-Sepharose conjugates and characterised by gel-filtration on Sephadex G-50 calibrated with molecular weight markers. After a 12-h fast, 10-20% of the immunoreactivity had a molecular weight of about 12 000, possibly due to precursors of secretin. Most of the remainder was smaller than secretin with molecular weight of less than 3000. This material comprised over 90% of the plasma immunoreactivity after a 36-h fast and may be due to degradation products.

Antibody Specificity↗
PubMed1979

The ultrastructure of frog mesenteric capillaries of known filtration coefficient.

The capillaries of the frog mesentery were investigated by transmission electronmicroscopy. The mean diameter of these vessels was 20 micrometers and a single layer of five to six endothelial cells (on average) contributed to each circumference. Their ultrastructure was very similar to that of mammalian capillaries of the continuous type [Bennett, Luft and Hampton, 1959]. The endotherlial cells, which contained many vesicles, were joined by specialized junctions and surrounded by a continuous basement membrane. Eleven capillaries were examined after the filtration coefficient of their walls had been investigated by the microperfusion micro-occlusion technique of Michel, Mason, Curry and Tooke [1974]. No abnormal appearances were observed even after the vessels had been perfused with protein free solutions which have been shown to increase filtration coefficient five fold. No morphological differences between capillaries were seen to accompany large differences in the filtration coefficients.

Animals↗
PubMed1978

Obtaining informed consent for mental health treatment.

A series of forms has been developed by staff at the Veterans Administration Hospital in Seattle in response to a Washington state law requiring that patients give informed consent to treatment. The forms, which describe the nature of the treatment and possible risks and benefits, follow four models: a single consent form that meets all the needs of a clinical unit; separate consent forms for various services of a clinical unit, such as medication or group or individual therapy; a limited-consent form combined with a brochure or fact sheet; and a consent form combined with a treatment contract. The authors report that use of the forms has required very little additional staff time and has not discouraged patients from entering treatment.

Hospital Bed Capacity, 300 to 499↗
PubMed1976

Osmotic reflextion coefficients of capillary walls to low molecular weight hydrophilic solutes measured in single perfused capillaries of the frog mesentery.

1. Individual capillaries of the transilluminated frog mesentery have been perfused with suspensions of human red cells in frog Ringer solution containing 1-0 g albumin 100 ml.-1. The outer surface of the mesentery has been washed with normal frog Ringer solution and with frog Ringer solutions made hypertonic by addition of one of the following solutes: sodium chloride (100 m-mole. 1.-1); urea (100 m-mole.1.-1); sucrose (20-50 m-mole. 1.-1); cyanocobalamin (8-5 m-mole. 1.-1). The temperature of the mesentery was between 14 and 16 degrees C in all experiments. 2. Wtih the mesentery superfused with normal Ringer, the filtration coefficient was determined from measurements of the rate of fluid filtration across the capillary wall, at a series of known capillary pressures (Michel, Mason, Curry & Tooke, 1974). Filtration coefficient varied from 0-69 X 10(-3) to 4-45 X 10(-3) mum. sec-1 .cm H2O-1 with an average value of 1-87 X 10(-3) mum. sec-1. cm H2O-1. 3. When the superfusate was made hypertonic by the addition of a test solute, the osmotic reflextion coefficient (sigma) of the capillary wall to test solute was calculated from the additional rate of filtration, the concentration of test solute in the superfusate and the filtration coefficient. Average values for sigma were: sodium chloride, 0-068 +/- 0-03 (three capillaries); urea, 0-071 +/- 0.015 (four capillaries); sucrose, 0-115 +/- 0-023 (seven capillaries); cyanocobalamin, 0-100 +/- 0-03 (three capillaries). 4. In further experiments, the osmotic reflextion coefficients to sodium chloride, urea and sucrose were determined in the same capillary. Five technically acceptable experiments were carried out. Although there were differences in the value of sigma between different capillaries, in any one capillary values of sigma were of the same magnitude and there appeared to be no significant trend with the molecular size of the test solute. 5. Our findings are inconsistent with the hypothesis that there is a single pathway for water and small hydrophilic molecules across the capillary wall. 6. Our results may be interpreted in terms of an exclusive channel for water in parallel with a channel shared by both water and small hydrophilic molecules. It is suggested that the exclusive water channel may be the membranes and cytoplasm of the endothelial cells and the shared channel may be located in the intercellular junctions. 7. Our data suggest the exclusive water channel represents about 10% of the total filtration coefficient in frog mesenteric capillaries. The shared channel shows relatively little restriction to the molecules investigated. Estimates of the volume flow throught the two channels are made for conditions where hydrostatic pressure differences and osmotic pressure differences are the driving forces.

Animals↗