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Biomedical subjects

A Shenkin

Publications and source records attributed to A Shenkin.

At least 91 records · Page 5Linked to original sources
PubMed1989

The utilisation of peripherally-administered intravenous nutrient solutions.

The utilisation of three peripherally-administered intravenous nutritional regimens has been evaluated in 42 patients on the first four days following surgery for colorectal cancer. A standard dextrose-saline (DS) regimen (n = 16) has been compared with an amino-acid (AA) regimen (n = 12) and a regimen consisting of glucose, amino-acid and fat (GAF) (n = 14). Fat and carbohydrate oxidation was calculated pre- and post-operatively using indirect calorimetry. Patients receiving AA showed a fall in carbohydrate oxidation (p < 0.01) and a rise in fat oxidation (p < 0.05) post-operatively, whereas no significant changes in fat and carbohydrate oxidation occurred in the DS and GAF groups. Cumulative nitrogen balance (NB) for the first four post-operative days was significantly better (p < 0.01) in the AA group (-10.3 +/- 3.8 g; mean +/- s.e.m.) than in the DS group (-25.3 +/- 3.1 g), due to an improved NB in the AA group on the first and second days only. Cumulative NB in the GAF group (+7.7 +/- 2.3 g) was significantly better (p < 0.01) than in the other two groups. Where the provision of peripheral intravenous nutritional support is desired, the use of a combination of glucose, amino-acid and fat is recommended.

Journal Article↗
PubMed1989

Clinical effects and adequacy of a new all-in-one dextrose-electrolyte-trace element preparation in patients on prolonged TPN.

We have devised a new all-in-one dextrose/electrolyste/trace element mixture (Polyfusor DY) and tested its efficacy in clinical practice. Polyfusor DY was designed to be combined with an amino-acid preparation and to be infused with lipid in a standard total parenteral nutrition (TPN) regimen. This standard regimen was formulated to provide minimum nitrogen, energy, fluid, electrolyte, vitamin and trace element requirements for the stable patient. The adequacy of currently recommended levels of provision of trace elements was tested in patients receiving long periods of intravenous nutrition. Eleven consecutive patients were fed from 13 to 280 days using TPN prescriptions based on this standard regimen. Two patients died but the nutritional state of the remainder improved. Serum concentrations of zinc, copper, chromium and manganese remained largely within or above the reference ranges, however the selenium content of Polyfusor DY (500 nmol/l) was marginally inadequate to maintain normal biochemistry. Pharmacy compounding time for the standard TPN regimen based on Polyfusor DY was 10.6 +/- 0.19 min (mean +/- SEM) compared with 22.5 +/- 0.30 min for non-standard TPN regimens prescribed independently by other clinicians (P < 0.001). A standard TPN regimen based on Polyfusor DY was clinically effective, in particular giving generally adequate trace element provision with a reduction in pharmacy time and costs.

Journal Article↗
PubMed1989

Subclinical riboflavin deficiency is associated with outcome of seriously ill patients.

The biochemical status of 152 patients in the Intensive Therapy Unit (ITU) was examined in relation to their clinical outcome. Patients who died in ITU or within one week of discharge were found to have significantly poorer riboflavin status than those who survived, but the majority of these measurements were within the normal range. Normal ranges established on a healthy population may therefore not be appropriate in investigation of vitamin nutritional status in seriously ill patients. These results do however suggest that riboflavin status is a risk factor in critically ill patients, and that subclinical riboflavin depletion may affect outcome.

Journal Article↗
PubMed1989

Hypothermia and the stress response to cardiopulmonary bypass.

There is no consensus on the optimal level of intraoperative hypothermia during cardiopulmonary bypass (CPB). To assess the effect of systemic cooling on the stress response to CPB, the acute phase and endocrine responses were measured in 20 male patients undergoing elective coronary artery surgery and randomised to an intraoperative blood temperature of 28 degrees C or 20 degrees C. The acute phase response was assessed by changes in the plasma concentration of C-reactive protein (CRP) and the endocrine response by the urinary excretion of the counter-regulatory hormones adrenaline, noradrenaline and cortisol. The groups were comparable with respect to age, anthropometric indices, cross clamp and bypass times. There was no significant difference in the groups in the acute phase response but the endocrine response was attenuated in the 20 degrees C group. These findings may have implications for the severely stressed preoperative patient.

Acute-Phase Proteins↗
PubMed1989

Acute phase reaction during chemotherapy in small cell lung cancer.

We have measured the serum concentration of the acute phase reactant, C-reactive protein (CRP), in 20 patients with histologically proven small cell lung cancer undergoing their first pulse of induction cytotoxic chemotherapy. Baseline CRP concentrations were raised in 16 of 20 patients (median baseline CRP 18.5 mg l-1; normal range less than 10 mg l-1). CRP levels more than doubled in 11 of 20 patients during induction chemotherapy. This acute phase reaction was seen in seven of the 10 chemosensitive patients, but was not observed in any of the five non-responding patients. Five patients were non-evaluable for chemoresponse. These data indicate that there is a previously undescribed quantifiable acute phase response during chemotherapy for small cell lung cancer which has potential for predicting chemoresponse.

Acute-Phase Reaction↗
PubMed1989

Plasma albumin and haemodilution: the problem of interpretation in sequential studies.

The ability of four formulae (3 based on packed cell volume and one on alpha-2 macroglobulin) to correct for postoperative dilutional changes in plasma albumin was assessed in 4 patients undergoing coronary artery surgery. Cardiopulmonary bypass is a stringent test of the efficacy of the formulae to correct for haemodilution as a large volume of fluid is added to the circulation in a relatively short period of time. Plasma albumin was measured 8 times in the perioperative period in the 4 patients and the clinical situation was mimicked in vitro by adding various volumes of diluent to whole blood. None of the formulae consistently corrected for predicted changes in plasma albumin concentration in vivo; two of the formulae corrected for in vitro changes in plasma albumin but the same formulae produced considerable over-correction when applied in vivo. The problem of correcting for perioperative dilutional changes in plasma albumin is discussed.

Coronary Artery Bypass↗
PubMed1989

Changes in iron, zinc, and copper concentrations in serum and in their binding to transport proteins after cholecystectomy and cardiac surgery.

Concentrations of iron, zinc, and copper and of their respective transport proteins transferrin, albumin, and ceruloplasmin were measured in serum after elective cholecystectomy and cardiac surgery. The pattern of changes in the concentrations of iron, zinc, and copper was reproducible, with an early increase in serum iron and zinc, then a decrease in the concentrations as these metals are dissociated from their serum transport proteins. Zinc and iron concentrations change before the increase in C-reactive protein, which begins 8 h after incision, whereas the copper concentration in the serum remains constant in the early postoperative period. Quantitative and kinetic differences were observed in both the trace metal and protein changes after cardiac surgery and cholecystectomy. These studies indicate the complexity of interpreting changes in trace elements in serum after surgery.

Adult↗
PubMed1989

The serum interleukin 6 response to elective surgery.

We have investigated changes in serum interleukin 6 (IL-6) in patients undergoing elective cholecystectomy. Serum IL-6 increased in all patients within 1.5 hour of incision, reaching a maximum between 1.5-4 hours after incision (median 50 U/ml; range 22-79 U/ml). The maximum serum IL-6 correlated with the length of the operation (r = 0.95). Serum C-reactive protein was not detectable until 8-12 hours post-incision, but maximum serum C-reactive protein did not correlate with maximum serum IL-6 concentration or length of operation. There was no consistent increase in plasma interleukin 1 or tumour necrosis factor following surgery. Serum IL-6 is an early marker of tissue damage and may be of value in the study of the metabolic response to injury.

C-Reactive Protein↗
PubMed1988

Influence of whole body protein turnover rate on resting energy expenditure in patients with cancer.

Whole body protein turnover and resting energy expenditure are measured simultaneously in weight stable and weight losing patients with lung (n = 22) or colorectal cancer (n = 38). These results were compared with those from weight stable and weight losing non-cancer controls (n = 22). Rates of whole body protein turnover were calculated from the plateau isotopic enrichment of urinary ammonia and urea following a primed, continuous, 24-h infusion of [15N]glycine. Resting energy expenditure was measured by indirect calorimetry. All groups of cancer patients had significantly elevated rates of whole body protein turnover (P less than 0.05) and synthesized, on average, 1.9 g/kg/day more protein compared with weight stable non-cancer controls. In contrast, the resting energy expenditure of cancer patients and controls was similar. Moreover, there was no correlation between individual rates of whole body protein turnover. Thus, although cancer patients had rates of whole body protein turnover which were 50-70% greater than controls, this did not result in a measurable increase in resting energy expenditure. The assumption that elevation of whole body protein turnover or resting energy expenditure causes weight loss in cancer patients must be an oversimplification. An acute phase protein response was observed in the majority of cancer patients. Although the presence of such an inflammatory response did not correlate with the rate of whole body protein turnover, the role of inflammatory mediators in the pathogenesis of disturbed protein metabolism in cancer patients merits further investigation.

Aged↗
PubMed1988

Rapid, sensitive detection of plasma IL-1 by extraction and bioassay.

A method for separating IL-1 from plasma inhibitors by silica extraction has been developed and coupled to a highly sensitive bioassay using the LBRM TG6 cell line and the I1-2 dependent HT2A cell line. Using this assay we have detected IL-1 activity in plasma from patients undergoing elective surgery.

Animals↗
PubMed1988

Thiamine deficiency in the critically ill.

There have been recent reports of hospitalised patients developing clinical thiamine deficiency, combined with much debate on the optimal supplementation of thiamine for the parenterally fed patient, particularly in the intensive therapy environment. We performed a retrospective study on 158 patients admitted to the Intensive Care Unit who required nutritional support. Patients who survived had significantly higher body thiamine status than those who died (p less than 0.01). There was no difference between serum albumin concentrations of the two groups. Twenty percent of the patients had biochemical evidence of thiamine deficiency and the mortality rate in these patients was 72% as compared with 50% mortality overall. Follow-up results suggest that current levels of thiamine supplementation are insufficient for critically ill intravenously fed patients. We suggest that patients be given a loading dose of 50-250 mg thiamine on admission to the Intensive Care Unit.

Adult↗
PubMed1988

Clinical aspects of vitamin and trace element metabolism.

An adequate provision of all micronutrients, vitamins and essential trace elements is necessary for maintenance of normal tissue function. In patients requiring nutritional support, these factors are essential for optimal utilization of the major nutrients and play a role in all aspects of intermediary metabolism. In this chapter, some of the main features of the micronutrients have been described, together with suggestions regarding their provision enterally or parenterally. For most of these nutrients, diagnostic methods are not available to permit accurate assessment of status and hence the level of provision necessary for optimal results. However, there is now sufficient understanding of nutritional requirements such that few patients should now develop clinical or biochemical signs of under- or overprovision of micronutrients.

Avitaminosis↗
PubMed1988

Cancer cachexia: influence of systemic ketosis on substrate levels and nitrogen metabolism.

The aim of this study was to determine whether a ketogenic diet could decrease nitrogen losses in cachectic cancer patients and at the same time reduce the supply of glucose for tumor energy metabolism. Five patients with malignant disease and severe weight loss (mean 32%) were fed via a fine bore nasogastric tube. A normal diet was given for 6 d and this was followed by 7 d of an isonitrogenous, isocaloric, ketogenic diet. Both diets were well tolerated. At 7 d the mean ketone body concentration in the blood of patients fed the ketogenic diet was 1.21 +/- 0.33 mM. This ketosis was associated with a significant reduction of the concentration in blood of glucose, lactate, and pyruvate (p less than 0.05). There was, however, no significant alteration in host N balance or whole-body protein synthesis, degradation, or turnover rates. Whether the change from glucose- to fat-derived energy substrates might reduce tumor growth rates in the long term remains to be determined.

Acidosis↗