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Biomedical subjects

J Powell-Tuck

Publications and source records attributed to J Powell-Tuck.

At least 19 recordsLinked to original sources
PubMed2004

Use of quantitative 16S ribosomal DNA detection for diagnosis of central vascular catheter-associated bacterial infection.

Many central vascular catheters (CVCs) are removed unnecessarily because current diagnostic methods for CVC-associated infection are unreliable. A quantitative PCR assay using primers and probe targeted to bacterial 16S ribosomal DNA was used to measure the levels of bacterial DNA in blood samples drawn through the CVC in a population of patients receiving intravenous nutrition. Bacterial DNA concentrations were raised in 16 of 16 blood samples taken during episodes of probable bacterial CVC-associated infection. Bacterial DNA concentrations were raised in 4 of 29 episodes in which bacterial CVC-associated infection was unlikely. The use of this technique has the potential to substantially reduce the unnecessary removal of CVCs.

Bacterial Infections↗
PubMed2002

Electronic poster presentations in BAPEN--a controlled evaluation.

INTRODUCTION: We sought to compare the quality of e-poster and traditional poster communications. METHODS: At the 2001 BAPEN congress, ten presenters were invited to supplement their poster by submitting its title and contents electronically. On projection, the submissions appeared as a poster. During chaired rounds, presenters 'talked to' the projection as if it were a traditional poster. They 'clicked' onto individual tables or figures to enlarge to full screen. A further 'click' returned the screen to poster format. Delegates attending two e-poster sessions, and a control group attending two simultaneous traditional poster rounds, responded to a questionnaire, on a scale 0--4, to statements which related: to the ability to (1) hear and (2) see well, (3) the posters'clarity and attractiveness, (4) whether the format of the session captured their interest and (5) encouraged discussion. Delegates also responded on how e-posters should be used in future meetings. Comparison was made using chi2 for trend. RESULTS: Questionnaires were returned from attendees at e-poster (27) and traditional (25) poster rounds. For all questions, the trend was in favour of e-posters with significant differences seen for 'seeing' (P= 0.009), 'interest capture' (P< 0.007) and 'encouragement of discussion' (P<0.05). Thirty-two vs one delegates thought that e-posters should be used in future, 28 vs 4 delegates thought that e-posters and traditional posters should be used together, but most(23 vs 8) thought that traditional posters should not be completely replaced. CONCLUSIONS: E-posters enable detailed search of a computer-based database of presentations, and viewing of the full content of all posters. Post-conference collaboration is enhanced by facilitating e-mail contact. E-posters should be used in tandem with traditional posters to improve the delivery of original communications.

Audiovisual Aids↗
PubMed2001

Should the food intake of patients admitted to acute hospital services be routinely supplemented? A randomized placebo controlled trial.

BACKGROUND: Many patients admitted to acute hospital services are underweight or harbour vitamin deficiencies. OBJECTIVES: To determine the effect on patient throughput of a policy of routine vitamin supplementation, and of early routine sipfeed supplementation in 'thin' patients (5-10% weight loss or body mass index 18-22). DESIGN: Factorial randomized placebo controlled trial of oral multivitamins from the first day of admission, and, after nutritional screening, of a nutritionally complete sipfeed from the second day in 'thin' patients. SETTING: Acute medical, surgical and orthopaedic hospital services of a London teaching hospital. PARTICIPANTS: 1561 patients admitted as emergencies were included in the vitamin study of which 549 were included in the sipfeed study. MAIN OUTCOME MEASURE: Length of hospital stay (LOS). RESULTS: Offering multivitamins to acute admissions resulted in a mean change (reduction) in LOS of -0.4 days 95% CI (-2-1.2days). The results suggest greater reductions for those discharged after 10 days: mean change=-2.3 days 95% CI (-5.7 to 1.2). Sipfeed supplementation was associated with an increased mean length of stay 2.8 days 95% CI (-0.8-6.3). 18% of acute admissions were classified undernourished on the basis of BMI, MUAC or percent weight loss combined. CONCLUSIONS: No benefit was observed for sipfeed intervention although a small benefit of less than one day is not excluded. Vitamin supplementation may have slight but economically important benefit.

Adult↗
PubMed2000

Insulin reduces leucine oxidation and improves net leucine retention in parenterally fed humans.

Protein metabolism during parenteral feeding was measured with and without euglycemic hyperinsulinemic clamping in five healthy human subjects using the primed continuous infusion of [(13)C]leucine (LEU) tracer methodology. All subjects underwent two periods of protein measurement. Subjects were randomized to have the clamp first or second. Two subjects had the clamp first, and they participated in another study in which the measurement period after the clamp was increased by another 2 h. Insulin reduced LEU oxidation (from 26 to 22 microM. kg(-1). h(-1); P < 0.05) and improved net LEU balance (from 3 to 7 microM. kg(-1). h(-1); P < 0. 05). The order of the clamp influenced the effects of insulin. With clamping performed second, insulin reduced LEU flux (from 152 to 134 microM. kg(-1). h(-1); P < 0.01), endogenous LEU rate of appearance (Ra; from 125 to 107 microM. kg(-1). h(-1); P < 0.01), and non-oxidative LEU disappearance (NOLD; from 128 to 113 microM. kg(-1). h(-1); P < 0.01). With clamping performed first, NOLD decreased after insulin was stopped (from 129 to 121 microM. kg(-1). h(-1); P < 0.05), but no change was seen in the flux and LEU Ra, despite the return of plasma insulin and amino acid concentrations to basal levels. The reduction in NOLD was accentuated with time and did not reach plateau even after 6 h and indicated a prolonged carry-over effect for NOLD and Ra. This effect was not seen for leucine oxidation.

Adult↗
PubMed2000

The postprandial rates of glycogen and lipid synthesis of lean and obese female Zucker rats.

OBJECTIVE: To determine the relative rates of glycogenesis and lipogenesis following administration of a test meal in lean and obese Zucker rats. PROTOCOL: Nine-week-old lean and obese Zucker rats were fasted overnight, then tube-fed a test meal of balanced composition amounting to 16kJ (lean rats and one group of obese rats) or 24kJ (one group of obese rats) and containing 200 mg 1-(13)C glucose. Immediately after the meal the rats were injected intraperitoneally with 5 mCi of 3H2O and killed 1 h later. METHODS: Glycogenesis was calculated from the incorporation of 3H into liver glycogen divided by the specific activity of plasma water. Lipogenesis was calculated similarly from the incorporation of 3H into saponifiable lipids in liver and perirenal adipose tissue. The proportion of glycogen synthesized by the indirect pathway via pyruvate was determined from the ratio of 3H labelling at positions C6 and C2 in the glycogen glucose residues. Glycogen synthesis from glucose was determined from the ratio of 13C enrichment in liver glycogen to that in plasma glucose. RESULTS: The rate of synthesis of glycogen was considerably lower in the livers of obese rats than those of lean controls, with the larger meal causing a small but significant increase in glycogenesis. The proportion of glycogen synthesized via pyruvate showed a non-significant increase in the obese rats, while the amount of glycogen synthesized from glucose was significantly decreased. Hepatic lipogenic rates were about five times higher in both groups of obese rats than the lean controls. In adipose tissue, lipogenesis per g tissue was slightly reduced in the obese rats, although there was clearly an increase in adipose tissue lipogenic activity per whole animal. The larger meal caused a greater rise in plasma glucose and insulin concentrations but did not affect lipogenic rates, although it did cause a greater suppression of lipolysis, as indicated by a lower plasma glycerol concentration. CONCLUSION: Ingested carbohydrate is partitioned predominantly into hepatic fatty acid synthesis in obese Zucker rats. Hepatic glycogen synthesis is suppressed and comes mainly from precursors other than glucose. The suppression of hepatic glycogen synthesis may contribute to the increased energetic efficiency of obese Zucker rats.

Animals↗
PubMed1999

The thiamin, riboflavin and pyridoxine status of patients on emergency admission to hospital.

The aim of this study was to assess the prevalence of thiamin, riboflavin and pyridoxine deficiencies at admission to an acute hospital. One hundred and twenty adult patients were selected at random from those admitted via the Accident and Emergency department over 3 days. Comparisons were made with a group of 80 healthy blood donors sequentially attending a local transfusion centre. The alcohol intake of 500 patients admitted sequentially via the same Accident and Emergency department was also assessed. Erythrocyte transketolase (ETK), glutathione reductase (EGR) and aspartate aminotransferase (EAA) coenzyme activation assays were used to determine thiamin, riboflavin and pyridoxine deficiencies. The prevalences of deficiency states in the inpatient group were 21, 2.7 and 32% for thiamin, riboflavin and pyridoxine deficiencies respectively with 49.2% being deficient in one or more vitamin. The mean alcohol intake in the group of patients in whom this was assessed was 9.7 units per week compared with 10 units per week amongst blood donors.

Adolescent↗
PubMed1999

A double blind, randomised, controlled trial of glutamine supplementation in parenteral nutrition.

BACKGROUND AND AIMS: To determine whether the inclusion of 20 g free glutamine as part of the nitrogen source of parenteral feeds reduces length of hospital stay or mortality. METHODS: In a randomised, double blind, controlled trial in 168 patients clinically accepted for parenteral nutrition, standard feeds were compared with feeds in which 3.8 g of the total nitrogen was replaced with the equivalent 20 g glutamine. A minimum of 11 g nitrogen/day was used in all patients. Daily intakes of energy and nitrogen were determined using a validated computer protocol and were similar for the two groups. All feeds included trace elements, vitamins, electrolytes, and minerals. RESULTS: A total of 85 patients received a median of eight (interquartile range 5-13) daily feeds containing glutamine while 83 received a median of eight (5-15) standard feeds. No difference between groups was detected for infective complications. Twenty control patients and 14 who had received glutamine died during their hospital stay (NS). Median length of stay was 32 (23-52) days on glutamine, which was not significantly different from the control value of 35 (25-55) days. Glutamine was associated with a significant (p<0.03) reduction in length of stay in surgical patients (45 days (range 29-81) versus 30 days (range 19-54)). CONCLUSION: The benefit from glutamine supplementation of parenteral feeds as used in this trial has not been proved. Supplementation may have advantages in surgical patients and in haematological malignancy. Further trials are required.

Adolescent↗
PubMed1998

A placebo controlled investigation of the effects of tryptophan or placebo on subjective and objective measures of fatigue.

OBJECTIVE: To examine the effect of L-tryptophan administration on subjective and objective measures of fatigue in healthy volunteers. SUBJECTS: Six healthy volunteers (4M:2F) were recruited from staff and students at the College. SETTING: Department of Human Nutrition, St. Bartholomews and the Royal London School of Medicine and Dentistry. DESIGN: Subjects were tested for central and peripheral fatigue using a visual analogue scale, flicker fusion frequency, grip strength, reaction time and wrist ergometry. In addition, plasma free tryptophan concentrations and Trp:LNAA ratio were determined. Measurements were made before, and at 1, 2, 3 and 4 h after drinking one of two test drinks. The drinks were of either caffeine free diet Coca-Cola (placebo) or caffeine free diet Coca-Cola plus L-tryptophan (30 mg/kg: active drink). Each of the six subjects was tested after placebo and active drink with a one week washout period between test days. RESULTS: Subjective fatigue was significantly increased following tryptophan compared to placebo (P < 0.002), and objective measures of central fatigue were significantly increased by tryptophan compared to placebo (flicker fusion frequency: P < 0.001; reaction time P < 0.001). No significant changes in grip strength were found following tryptophan compared to placebo, but a significant increase in ergometric work output was seen (P < 0.001). CONCLUSION: Tryptophan ingestion in the quantity 30 mg/kg leads to increased subjective and central fatigue. Increases in work output observed following tryptophan may be as a result of a reduced perception of discomfort during ergometry.

Adult↗
PubMed1997

Post-prandial changes in measures of fatigue: effect of a mixed or a pure carbohydrate or pure fat meal.

OBJECTIVES: To assess the changes in measures of fatigue after meals of varying composition, and to compare the relation of the fatigue with changes in the plasma tryptophan:large neutral amino acids (Trp:LNAA) ratio. SUBJECTS: Sixteen healthy volunteers were recruited from staff and students at the College. DESIGN: Subjects were tested for central and peripheral fatigue using a visual analogue scale, flicker fusion frequency, grip strength, reaction time and wrist ergometry. In addition, plasma amino acid concentrations and Trp:LNAA ratio were determined. Measurements were made before, and at 1, 2, 3 and 4 h after drinking one of three liquid test meals. The meals were isoenergetic (1672 kJ) and were of mixed carbohydrate, fat and protein, or of pure carbohydrate or pure fat. SETTING: Department of Human Nutrition. RESULTS: Subjects consuming the pure carbohydrate meal reported more subjective feelings of fatigue and had slower reaction times. Aspects of central fatigue were greater in subjects consuming a pure fat meal. The Trp:LNAA ratio was depressed in those consuming a pure fat or mixed meal and raised only after pure carbohydrate. CONCLUSIONS: Central and subjective fatigue may be influenced by raised plasma free tryptophan to competitor amino acid ratios induced by carbohydrate intake but other aspects of central arousal are affected by fat intake.

Adult↗
PubMed1997

Four years' experience of an undergraduate medical nutrition course.

In 1992 the medical colleges of The Royal London and St Bartholomew's hospitals launched a new curriculum in which basic medical sciences were to be integrated with early exposure to clinical medicine in the first phase. The curriculum was to be modular and integrative, combining clinical and medical-science-based teaching of body systems, rather than the traditional teaching by departmental discipline. We describe the inception, content and evaluation of a 7-day course on nutrition which was developed as part of this curriculum. It was rated highly by the students, whose feedback led to important modifications. The programme works well in practice, and could provide a useful guide for other schools about to set up nutrition courses for medical students.

Curriculum↗