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Biomedical subjects

J S Wilkinson

Publications and source records attributed to J S Wilkinson.

15 recordsLinked to original sources
PubMed1989

Establishment of a system to standardize acceptability criteria for alanine aminotransferase activity in donated blood.

A multilaboratory study was conducted to develop a system for standardizing alanine aminotransferase (ALT) acceptability criteria ("cutoffs") for donated blood. Without standardized cutoffs, each laboratory must develop its own cutoff, and this may not make optimal use of ALT testing to reduce transmission of non-A, non-B hepatitis (NANB). Defining an ALT acceptability criterion in absolute terms is necessary because relative cutoffs based on local donor populations may be affected by the prevalence of NANB in each community. This study involved 16 laboratories using 23 different analytic systems. The ALT results of the analysis of a plasma reference sample could be used to translate mathematically a single, absolute cutoff to units applicable to each analytic system. The distribution of ALT results in 1.4 million donations from across the country was established; basing the cutoff on this sample avoids the problems inherent in using a local donor base to establish a cutoff. We propose the implementation of a system to standardize ALT acceptability criteria to an activity level defined by analysis of a nationwide donor sample.

Alanine Transaminase↗
PubMed1988

Blood volume change during isolated ultrafiltration and combined ultrafiltration-dialysis.

Despite extensive study of the difference in the cardiovascular response to ultrafiltration in isolation and during haemodialysis, there is still disagreement in the literature as to whether or not there is a difference in the efficiency of plasma refilling between the two procedures. We believe that this results both from the use of inadequate techniques to measure change in blood volume and shortcomings in experimental design. We have employed novel methods in ten patients to study plasma refilling during isolated ultrafiltration and dialytic ultrafiltration. Measurement of blood pressure and heart rate confirmed the inferior cardiovascular tolerance to haemodialysis observed by others. However, no difference in the rate of plasma refilling could be demonstrated. Our observations suggest that the superior tolerance to isolated ultrafiltration is not explained by differences in vascular refilling.

Adult↗
PubMed1988

Dialysis-induced change in erythrocyte volume: effect on change in blood volume calculated from packed cell volume.

Blood volume (BV) change during hemodialysis is often monitored by packed cell volume (PCV). This assumes erythrocyte volume is constant. We tested this by dialyzing 5 patients for 2 hours against high (154 mmol/l), normal (140 mmol/l) and low (126 mmol/l) dialysate sodium concentrations. Erythrocyte water content, calculated from measured blood and plasma water contents, decreased with high and increased with low dialysate sodium concentrations. Erythrocyte volume, calculated from mean corpuscular hemoglobin concentration (MCHC) decreased 3.8% with high concentration dialysate and increased 2.5% when dialysate concentration was low. These changes correlated significantly (r = 0.80, p less than 0.01) with alterations in plasma sodium. Mean corpuscular volume (MCV), measured with a Coulter-S Plus Counter did not alter because of a methodological artefact. BV change can be calculated from PCV when plasma concentrations of osmotically active substances are changed only if allowance is made for altered erythrocyte volume.

Adult↗
PubMed1987

Effect of dialysate composition on intercompartmental fluid shift.

Effect of dialysate composition on intercompartmental fluid shift and hemodynamics was studied in 12 patients during 1.5 or 2 hours of hemodialysis without net ultrafiltration, using high (H;Na 154 mmol/liter), normal (N;Na 140 mmol/liter) or low (L:Na 126 mmol/liter) concentration dialysate. H dialysate was associated with a small (0.9%) increase in blood volume, a larger increase in plasma volume and a decrease in erythrocyte volume. L dialysate resulted in a 2.3% decrease in blood volume, a larger decrease in plasma volume and an increase in erythrocyte volume. N dialysate gave results which were intermediately between the other two dialysis conditions. There was no difference in the post-dialysis mean arterial pressure between the groups, although heart rate increased more during H dialysis than during the other two conditions. Change in blood and erythrocyte volume correlated significantly with change in plasma Na concentration and osmolality, but not with change in plasma urea concentration. We conclude that dialysate composition affects the movement of water into and out of the plasma and erythrocytes in a manner that can be accounted for by altered plasma concentrations of osmotically active substances.

Adult↗
PubMed1978

Hyperlipaemia in ponies.

The case histories and clinical findings of 15 ponies with hyperlipaemia are presented. The disease was characterised by hyperlipidaemia with inappetance, progressing somnolence, muscle fasciculation, diarrhoea, and ventral oedema as the predominant clinical findings. Post mortem examinations of 12 ponies showed extensive lipidosis and vascular thrombosis with widespread secondary changes. Most cases occurred in late pregnant and early lactating mares in the summer months and it is postulated that the disease was initiated in this group by a falling nutritional plane in the face of high nutrient requirements.

Animals↗
PubMed1976

A clinincal evaluation of abdominal paracentesis in the horse.

This paper evaluates the usefulness of abdominal paracentesis as a diagnostic aid in abdominal disease in the horse and in particular considers whether or not it can be effectively utilised as an indication for surgical intervention in cases of colic. The results are based upon peritoneal fluid samples collected from 20 normal horses and from 20 cases of colic and peritonitis. Peritoneal fluid was collected from standing horses by inserting a bovine teat cannula into the horses abdomen through the linea alba after desensitisation of the skin on the ventral midline with local anaesthetic. Usually, from 3-5 ml of fluid could be collected from a normal horse. This was either clear or cloudy white or yellow in colour and contained 3310 +/- 703 leucocytes/ml consisting of 63.81% neutrophils, 1.4 +/- 1.3% monocytes, 13.5 +/- 4.3% mesothelial cells and 21.25% +/- 6.2% lymphocytes. Protein content was 1.29 +/- .4g/100ml. Changes in the volume, colour, cellular constituents and protein content of fluid, characterised abdominal disease. In cases of colic, discolouration of the abdominal fluid was found to be the most consistent, reliable and useful indication of bowel necrosis. This in turn indicated the need for urgent surgical intervention rather than conservative treatment. Discolouration commenced early in the course of the disease even while the segment of bowel involved was still viable. Increased volume of fluid, elevated leucocyte count (statistically significant at the 5% level), increased neutrophil percentage and elevated protein levels were less useful criteria for determining the integrity of the bowel. Similar changes from the normal were also found in cases of peritonitis. Here, however, microscopic examination of cells in a smear of the fluid was more useful, as phagocytosis and abnormal cell types indicating infection or inflammation could be seen readily, and a diagnosis based upon these findings. It was concluded that abdominal paracentesis, although no substitute for thorough clinical examination, was a valuable diagnostic aid for abdominal conditions of the horse.

Animals↗