R.G. Clark

A simple computer model for insulin-receptor interactions and insulin dependent glucose uptake by adipocytes.

A simple computer model is described for the simulation of insulin binding to cell surface receptors on adipocytes and the subsequent stimulation of glucose uptake. The model is based on the currently accepted physiology and biochemistry of insulin action. The model successfully simulated changes in sensitivity to insulin with changes in receptor numbers seen with in vitro experiments; it is also consistent with the proposal that an increased rate of insulin-receptor complex internalisation should lead to an insulin-resistant state. The model also suggests that such an insulin-resistant state should not be affected by a subsequent increase in the rate of return of internalised receptors to the outer cell surface.

A simple computer model for albumin and water distribution and flux in man

The physiological and mathematical basis for a simple computer model of albumin and water distribution in man is described. The factors which are important in determining albumin and water flux are discussed and some clinical implications are considered.

Long term parenteral nutrition in the management of severe Crohn's disease

Twelve patients with active severe Crohns disease, who failed to respond to medical treatment, received total parenteral nutrition (T.P.N.) via a Broviac long term feeding catheter for periods of 35-190 days prior to surgery. The 10 patients who were non-oedematous increased their mean weight by 3.3 Kg (p<0.01) and their mean plasma albumin by 5.80 g/l (p<0.025) after 28 days T.P.N. There were two episodes of catheter-related sepsis. Although the mean Crohns disease activity index was significantly reduced from 364.50 (+/-91.51) to 236.75 (+/-121.29) (p<0.005) after 28 days T.P.N., all 12 patients were found to have active disease at operation. There was no post-operative mortality and the only major post-operative morbidity was a pelvic abscess following a panproctocolectomy. It is concluded that long term T.P.N. does not eliminate the need for surgery, but it may improve the nutritional status and reduce the post operative morbidity of malnourished patients with severe Crohns disease.

Undernutrition in elective colorectal surgery. Implications for post operative morbidity

The nutritional status of 65 patients undergoing elective colorectal surgery was assessed using 5 conventional nutritional indices, percentage ideal weight, mid arm muscle circumference, triceps skin fold thickness, serum albumin and serum total iron binding capacity. Only 9 patients had values for all five indices which are taken to represent normal nutritional status. This survey suggests that many patients undergoing elective colorectal surgery in this country have subnormal values of the indices commonly used for nutritional assessment but only severe depression of serum albumin however appears to adversely affect the outcome of surgery.

A comparison of immediate post-operative enteral and parenteral nutrition in patients with gastric carcinoma

Abstract Fourteen patients with gastric carcinoma were studied in the first post-operative week following the administration of immediate post-operative nutrition. Eight received Clinifeed ISO® enteral feed and six received parenteral nutrition (TPN) (Vamin-glucose, dextrose and Intralipid®). Plasma albumin and transferrin concentrations decreased post-operatively in both groups, but did not differ significantly between the groups. Positive nitrogen balance was achieved on the fifth post-operative day in the enteral group and on the first post-operative day in the TPN group. There were no significant differences in the pre and post-operative weights and anthropometric measurements in either group. One patient in each group developed a subphrenic abscess, six patients in the enteral group experienced nausea and diarrhoea and two of these also vomited. The results indicate that immediate post-operative enteral nutrition is accompanied by a degree of negative nitrogen balance because a 3 day ‘build up’ period is necessary to achieve a full intake and with a higher incidence of minor gastro-intestinal complications which are easily controlled.

Effect of nutrition support on clinical outcome

There are historical reasons why assessment of clinical outcome came late in the development of artificial nutrition support (ANS). The contrast between a relentless deterioration associated with total starvation in a serious complicated disease for which no nutritional remedy was available and the dramatic clinical improvement after even the most rudimentary artificial nutrition regimen was so striking that statistical proof seemed unnecessary. It is interesting to note that the obvious advantages which appeared at that time to prove the value of ANS are quite different from the outcome factors being used now to prove value and efficacy. Early users of ANS were impressed by the marked early improvement in nutritional well-being and the more manageable aspects of patient care such as nursing care and fluid and electrolyte balance, with the bonus of additional time to make more leisured clinical decisions and avoid ‘last ditch’ radical interventions, frequently fatal. The role of ANS was therefore seen as supporting homeostasis and improving nutritional status and not directly altering the course of disease. Currently, outcome is seen in a clinical context demanding measurable benefits to be clearly visible to the untutored eye in economic terms as improved bed occupancy, decreased length of stay and better cost per measured unit, all of which emanate from an altered clinical course. However, for our purposes at the end of ESPEN’s second decade, assessment of outcome should have a broader base reflecting how successful ANS is as a food both in the absence and presence of acute disease and whether it can influence positively the course of an acute disease.

Priapism — A complication of home parenteral nutrition?

A case of priapism in a patient receiving home parenteral nutrition is reported. To our knowledge this is the first such case to occur in a patient receiving home parenteral nutrition. The literature is reviewed and the possible aetiology discussed.