PubMed Health⌕ Search

Biomedical subjects

D E Thomas

Publications and source records attributed to D E Thomas.

At least 19 recordsLinked to original sources
PubMed2006

Exercise for type 2 diabetes mellitus.

BACKGROUND: Exercise is generally recommended for people with type 2 diabetes mellitus. However, some studies evaluate an exercise intervention including diet or behaviour modification or both, and the effects of diet and exercise are not differentiated. Some exercise studies involve low participant numbers, lacking power to show significant differences which may appear in larger trials. OBJECTIVES: To assess the effects of exercise in type 2 diabetes mellitus. SEARCH STRATEGY: Trials were identified through the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and manual searches of bibliographies. Date of last search was March 3, 2005. SELECTION CRITERIA: All randomised controlled trials comparing any type of well-documented aerobic, fitness or progressive resistance training exercise with no exercise in people with type 2 diabetes mellitus. DATA COLLECTION AND ANALYSIS: Two authors independently selected trials, assessed trial quality and extracted data. Study authors were contacted for additional information. Any information on adverse effects was collected from the trials. MAIN RESULTS: Fourteen randomised controlled trials comparing exercise against no exercise in type 2 diabetes were identified involving 377 participants. Trials ranged from eight weeks to twelve months duration. Compared with the control, the exercise intervention significantly improved glycaemic control as indicated by a decrease in glycated haemoglobin levels of 0.6% (-0.6 % HbA(1c), 95% confidence interval (CI) -0.9 to -0.3; P < 0.05). This result is both statistically and clinically significant. There was no significant difference between groups in whole body mass, probably due to an increase in fat free mass (muscle) with exercise, as reported in one trial (6.3 kg, 95% CI 0.0 to 12.6). There was a reduction in visceral adipose tissue with exercise (-45.5 cm(2), 95% CI -63.8 to -27.3), and subcutaneous adipose tissue also decreased. No study reported adverse effects in the exercise group or diabetic complications. The exercise intervention significantly increased insulin response (131 AUC, 95% CI 20 to 242) (one trial), and decreased plasma triglycerides (-0.25 mmol/L, 95% CI -0.48 to -0.02). No significant difference was found between groups in quality of life (one trial), plasma cholesterol or blood pressure. AUTHORS' CONCLUSIONS: The meta-analysis shows that exercise significantly improves glycaemic control and reduces visceral adipose tissue and plasma triglycerides, but not plasma cholesterol, in people with type 2 diabetes, even without weight loss.

Blood Glucose↗
PubMed2003

Knowledge and use of evidence-based nutrition: a survey of paediatric dietitians.

OBJECTIVE: To survey paediatric dietitians' knowledge and use of evidence-based nutrition (EBN). DESIGN: Cross-sectional survey using reply-paid questionnaires. SUBJECTS: Paediatric dietitians in Australian teaching hospitals. MAIN OUTCOME MEASURES: Age, sex, appointment, clinical practice, research activities; attitudes to, training in and use of EBN; and perceived barriers to use of EBN. STATISTICAL ANALYSIS: Data were analysed using descriptive statistics (SPSS). RESULTS: Fifty-nine (86%) of 69 questionnaires were returned. Most (97%) dietitians were women working full-time (63%), mean age 37 years (+/-9 SD). Most (75%) dietitians encountered knowledge gaps less than five times per week and most (87%) questions related to therapy. The majority (95%) performed their own literature searches, less than five times per month. All had access to >or=1 electronic literature databases including Medline (n = 58, 98%), Cochrane Library (n = 44, 75%) and CINAHL (n = 35, 59%). Information sources used most often were Medline and consultation with colleagues. Reported barriers to using EBN were lack of time (n = 53, 90%) or lack of skills for critical appraisal of published articles (n = 51, 86%) or literature searching (n = 48, 81%). While 53 (90%) believed in an evidence-based approach, 43 (73%) either did not practise EBN or rated themselves as beginners. CONCLUSION: Most dietitians favoured evidence-based practice, but reported lack of time, skills or rapid access to electronic databases as barriers to its practice.

Adult↗
PubMed2003

Preparation of monoclonal antibodies using the electrophoresis separation instrument, Gradiflow.

Gradiflow, a preparative electrophoresis separation device, was utilized to develop and test generic protocols for the preparation of monoclonal antibodies (MAbs) from tissue culture supernatant and ascites fluid. The charge based protocol separated the high pI antibodies from the lower isoelectric points (pI) contaminants by either moving the antibody (ascites fluid) or contaminants (tissue culture supernatant) through a polyacrylamide separation membrane. A total of 60 separations were performed with tissue culture supernatant, and a further 30 separations with ascites fluid. The Gradiflow procedure resulted in higher yields, equivalent functionality and similar purity compared with affinity chromatography antibody preparation on protein A and G. The results suggest that the Gradiflow protocols may be an alternative method of antibody preparation for these samples.

Animals↗
PubMed2001

Referrals to a hospital-based child abuse committee: a comparison of the 1960s and 1990s.

OBJECTIVE: Although reports of child maltreatment have increased yearly since national data were first collected in 1976, little information is available about changes in the characteristics of children reported. Therefore, to examine changes over time in recognition and reporting in a medical setting, we compared referrals to a hospital-based child abuse committee in the late 1960s and early 1990s. DESIGN: Retrospective, cross-sectional review of medical records and logs of the hospital's child abuse committee. SETTINGS: Ambulatory, emergency, and inpatient services at Yale-New Haven Hospital. PATIENTS: Medical records were reviewed for 101 of the 165 children referred to the child abuse committee in 1968-1969 (early group) and 107 of the 843 children referred in 1990-1991 (late group). Cases of sexual abuse were excluded. RESULTS: Referrals for nonsexual abuse cases increased from 80 children per year in the early group to 181.5 per year in the late group; the late group was characterized by a larger number of newborn referrals (1% vs. 52%, p < .001). When non-newborns were compared, the two groups were similar with respect to gender and race, but the late group had fewer patients with private insurance (31% vs. 12%, p < .05). The late group also had more female-headed households (32% vs. 67%, p < .05) and more parents with a history of substance abuse (4% vs. 49%, p < .001). Excluding newborns, who were all classified as "at-risk," the types of problems were classified as abuse (41% early vs. 29% late), neglect (41% vs. 35%), and "at-risk" (16% vs. 35%). Although the types of injuries were similar: superficial injuries (20% vs. 16%), burns (9% vs. 8%), and fractures (6% vs. 4%), fewer maltreated children suffered physical injuries in the late group (71% vs. 49%, p < .05). CONCLUSIONS: A substantial change has occurred in referrals to the hospital's child abuse committee for abuse or neglect. Most referrals have become socially high-risk newborns and children or children with minimal injuries. This shift is likely due to broader definitions of maltreatment and earlier recognition of troubled families.

Adolescent↗
PubMed2000

Evaluation of the iScreen digital screening system for amblyogenic factors.

BACKGROUND: A digital photoscreener, the iScreen screening system, is now available to detect amblyogenic factors. We carried out a prospective study to evaluate the accuracy of the device in detecting anisometropia, significant refractive error, strabismus and opacities of the ocular media. METHODS: A total of 449 consecutive patients (median age 7 years) from a private pediatric ophthalmology practice underwent screening with the iScreen photoscreener operated by a minimally trained technician. The results were compared to the masked clinical examination of a pediatric ophthalmologist. RESULTS: The iScreen device had a sensitivity of 92.4%, specificity of 89.1%, positive predictive value of 94.1% and false-negative rate of 13.8%. Of the 21 patients with a false-negative result, 12 had myopia of less than -1.50 dioptres. High hyperopia was missed in two patients, high astigmatism in one, unequal cylindrical error in one and strabismus in five. INTERPRETATION: The iScreen digital photoscreener produced accurate and timely screening for potentially amblyogenic defects in the study population.

Adolescent↗
PubMed2000

A cross-sectional survey of the opinions on weight loss treatments of adult obese patients attending a dietetic clinic.

OBJECTIVE: To investigate the views and opinions on weight loss treatments of adult obese patients attending a dietetic clinic. DESIGN: Cross-sectional survey. SUBJECTS: 161 adults attending dietetic outpatients clinics in Portsmouth for obesity with a body mass index of at least 30 kg/m2. MEASUREMENTS: Self-administered questionnaire developed from a series of focus groups with obese adults. Key topics were previous attempts to lose weight, methods used, the role of physical activity and patients' views about treatment from health professionals. RESULTS: The preferences and usefulness of different methods to lose weight varied according to the number of attempts to lose weight, gender, age, body mass index and medical condition of the patient. Men were less likely to use special slimming products, attend slimming groups and swimming than women (odds ratios (95% confidence interval), 0.1 (0.03-0.6) for slimming groups other than Weight Watchers, 0.3 (0.1-0.80) for special slimming products and 0.3 (0.1-0.6) for swimming). Men were more likely to use physical activity (2.6 (1.1-6.2)) and in particular walking (3.7 (1.0-13.6)) and cycling (2.8 (1.0-7.6)) and were more likely to see the dietitian (3.8 (1.4-9.9)) than women. Those with more than 10 attempts to lose weight were more likely to see the dietitian (3.6(1.6-8.2)), use Weight Watchers (2.5 (1.1-5. 6)) and newspapers and magazines (4.4 (1.8-10.9)) than those with fewer attempts. The younger age group were more likely to use more vigorous forms of exercise (4.2 (1.6-11.2) for keep fit and 3.7 (1. 5-9.6) for cycling) than the older subjects. The most obese were more likely to have negative views on their treatment by health professionals (4.4 (1.9-9.8) 'chairs are never big enough' and 4.0 (1.8-8.8) 'I am regarded as a second class citizen') than those who were less obese. Those without a medical condition were more likely to exercise (2.8 (1.3-6.3)) and use books (4.8 (2.0-11.2)) than those with a medical condition. CONCLUSION: The views of obese people should be considered when planning services for the treatment of obesity and a variety of options should be available. International Journal of Obesity (2000) 24, 164-170

Adolescent↗
PubMed1999

Reuse of single-use medical devices: informed consent and physician liability.

This overview addresses the controversial practice of reuse and reprocessing of single-use medical devices and the issues this practice raises for physician liability. Specifically, we describe the health risks associated with medical device reprocessing, analyze the market costs arising from the reuse and reprocessing of single-use medical devices, and discuss physician liability for failure to obtain informed consent of the patient for the use of reprocessed single-use medical devices.

Disposable Equipment↗
PubMed1998

Hepatic artery aneurysm rupture: case report, imaging findings, and literature review.

Hepatic artery aneurysm rupture is a rare condition that requires urgent diagnosis and treatment in order to avoid a potentially fatal outcome. The clinical presentation is often non-specific. The classic triad of abdominal pain, gastrointestinal hemorrhage, and obstructive jaundice occurs in less than one-third of cases. Physical examination is rarely helpful since bruits, masses or pulsations are infrequent. Radiologic imaging provides the best tool to early diagnosis. Angiography has historically been the gold standard of diagnosis and is needed prior to radiologic intervention. Computerized tomography, doppler ultrasound and even magnetic resonance imaging have all demonstrated visceral artery aneurysms with success. Conventional treatment has included surgical ligation and resection. More recently transcatheter embolization or even percutaneous transhepatic injection of thrombin has been successfully performed by the interventional radiologist. This article discusses the clinical presentation, imaging findings, and review of the literature of this elusive entity.

Aged↗
PubMed1996

Modulation of human T-lymphocyte plasma membrane Ca2+ permeability by imidazole antimycotics.

The role of cytochrome P-450 in the regulation of plasma membrane Ca+2 permeability of human peripheral T-lymphocytes by intracellular Ca+2 was examined. We assessed the effect of imidazole inhibitors of cytochrome P-450 on the intracytoplasmic free Ca+2 ([Ca+2]i) response generated using the microsomal ATPase inhibitor thapsigargin (THG) to deplete the intracellular Ca+2 stores. Econazole, miconazole and clotrimazole dramatically inhibited the THG mediated increase in [Ca+2]i and induced an increase in [Ca+2]i themselves. This inhibitory effect was previously observed in other cell systems and was attributed to inhibition of cytochrome P-450 by these agents. However, we evaluated a variety of structurally dissimilar P-450 inhibitors and found that none affected [Ca+2]i, indicating that the mechanism of imidazole action does not involve P-450.

Antifungal Agents↗
PubMed1994

Plasma glucose levels after prolonged strenuous exercise correlate inversely with glycemic response to food consumed before exercise.

It was hypothesized that slowly digested carbohydrates, that is, low glycemic index (GI) foods, eaten before prolonged strenuous exercise would increase the blood glucose concentration toward the end of exercise. Six trained cyclists pedaled on a cycle ergometer at 65-70% VO2max 60 min after ingestion of each of four test meals: a low-GI and a high-GI powdered food and a low-GI and a high-GI breakfast cereal, all providing 1 g of available carbohydrate per kilogram of body mass. Plasma glucose levels after more that 90 min of exercise were found to correlate inversely with the observed GI of the foods (p < .01). Free fatty acid levels during the last hour of exercise also correlated inversely with the GI (p < .05). The findings suggest that the slow digestion of carbohydrate in the prevent food favors higher concentrations of fuels in the blood toward the end of exercise.

Adult↗
PubMed1991

Fetotoxic alterations in the normal ontogenies of rat microsomal and lysosomal enzymes.

The activity patterns during development for acid phosphatase (Ac-P), alkaline phosphatase (A1-P), beta-glucuronidase (beta G), and UDP-glucuronyltransferase (UDPGT) have been determined in various tissues of the rat for corn oil and distilled water controls as well as in animals prenatally exposed to four fetotoxic chemicals. Postnatal assays were performed on both sexes separately. In control animals, tissue-specific differences between male and female activity levels were found for UDPGT. In the liver of mature offspring, enzyme activity was greater in males than in females. Although no sex difference was observed in the intestine, the kidneys of females exhibited higher values than those of males. An original computer-assisted methodology is presented, designed (a) to permit a mathematical description for the complex curves exhibited by these ontogeny profiles, and (b) to assess the statistical significance of chemical-induced alterations in these complex developmental patterns, specifically, to target sensitive periods and subtle changes near the fetotoxic threshold. Oral administration (days 6-18 of gestation) of 3,3',4,4'-tetrachlorobiphenyl (4CB) to pregnant females resulted in an induction of liver UDPGT activity in offspring postnatally, and some alterations in the perinatal pattern of beta G in the same tissue. This treatment also produced differences in the intestinal patterns of Ac-P and male UDPGT. No significant changes were observed in offspring exposed to diethylstilbestrol (DES). Treatment with zeranol (ZN) caused reductions in activity over the entire postnatal period for beta G in liver, brain, intestine, and kidney, for A1-P in brain, and for Ac-P in the intestine. Cadmium-treated dams gave birth to offspring that exhibited slightly altered ontogenies only in intestine for UDPGT and AcP. The alterations in these developmental profiles indicate periods of increased sensitivity, and may be useful in directing more specific studies into the fetotoxic mechanisms of these compounds.

Acid Phosphatase↗
PubMed1991

Carbohydrate feeding before exercise: effect of glycemic index.

Low glycemic index (GI) foods may confer an advantage when eaten before prolonged strenuous exercise by providing a slow-release source of glucose to the blood without an accompanying insulin surge. To test this hypothesis, eight trained cyclists pedalled to exhaustion one hour after ingestion of equal carbohydrate portions of four test meals: lentils, a low GI food (LGI); potato, a high GI food (HGI), and glucose and water. Plasma glucose and insulin levels were lower after LGI than after HGI from 30 to 60 min after ingestion (p less than 0.05). Plasma free fatty acid (FFA) levels were highest after water (p less than 0.05) followed by LGI and then glucose and HGI. From 45 to 60 min after ingestion, plasma lactate was higher in the HGI trial than in the LGI trial (p less than 0.05) and remained higher throughout the period of exercise. The rank order from lowest to highest for total carbohydrate oxidation during exercise was water, lentils, glucose and potato. Endurance time was 20 min longer after LGI than after HGI (p less than 0.05). These findings suggest that a low GI pre-game meal may prolong endurance during strenuous exercise by inducing less post-prandial hyperglycemia and hyperinsulinemia, lower levels of plasma lactate before and during exercise, and by maintaining plasma glucose and FFA at higher levels during critical periods of exercise.

Analysis of Variance↗
PubMed1991

Composition of the subsistence foods of the Wopkaimin people of Papua New Guinea.

Forty-four samples of food, representing 35 species of animals and plants consumed by the Wopkaimin people of highland Papua New Guinea, were analyzed for their nutrient composition, many for the first time. Moisture, protein, fat and minerals (Na, K, Mg, Ca, Fe, Zn, Cu) were assayed directly. Energy and total carbohydrate content were calculated. The animal foods were high in protein, Fe and Zn. Ca was very high (greater than 1000mg/100g) in birds, frogs and fish containing soft edible bones. Leafy vegetables were relatively high in protein, iron and calcium. The five samples of taro (Colocasia esculenta) showed wide variation in composition. The results provide further information on the nutritional value of Papua New Guinean foods.

Food Analysis↗
PubMed1990

Solid-state 13C-NMR studies of the effects of sodium ions on the gramicidin A ion channel.

End-to-end helical dimers of gramicidin A form transmembrane pores in lipid bilayers, through which monovalent ions may pass. The groups within the peptide that interact with these ions have been studied by application of solid-state spectroscopic methods to a series of gramicidin A analogues synthesized with 13C in selected peptide carbonyl groups. The resonances of D-Leu10, D-Leu12 and D-Leu14 analogues were perturbed in the presence of 0.16 M sodium ions, whereas the resonances of the carbonyls of Gly2, Ala3, D-Leu4 and Val7, which are closer to the formylated N-terminal end of the peptide, were unaffected. The observed changes in chemical shift anisotropy are indicative of a change in orientation of the abovementioned leucine carbonyls.

Dimyristoylphosphatidylcholine↗
PubMed1989

Effect of acyl chain length on the structure and motion of gramicidin A in lipid bilayers.

The transmembrane ion transport properties of gramicidin A have previously been shown to dependent on the nature of its lipid environment. Solid-state NMR spectroscopic studies of 13C-labelled analogues of gramicidin in oriented multilayers of phosphatidylcholine have shown that variation of the lipid hydrocarbon chain length has no effect on the structure or orientation of the peptide backbone.

Carbon Isotopes↗
PubMed1989

Determination of the structure of a membrane-incorporated ion channel. Solid-state nuclear magnetic resonance studies of gramicidin A.

Solid-state nuclear magnetic resonance (NMR) measurements on 13C-labeled analogues of the ion channel-forming peptide, gramicidin A, have been used to directly determine the structure of this peptide in lipid membranes. Seven gramicidin analogues, each labeled in a single carbonyl group of gly2, L-ala3, D-leu4, L-val7, D-leu10, D-leu12, or D-leu14 were synthesized by the solid-phase method. These gramicidin analogues were incorporated into aligned multilayers of dimyristoylphosphatidylcholine, or diether lipid bearing 14- or 16-carbon chains, at a 1:15 peptide:lipid mole ratio. Proton-enhanced, 13C, solid-state spectra were obtained at several temperatures and over a range of sample orientations with respect to the spectrometer magnetic field to permit accurate measurement of the chemical shift anisotropies. The observed anisotropies indicate that all of the labeled carbonyl bonds are oriented almost parallel to the molecular long axis and perpendicular to the lipid bilayer plane. These orientations are consistent with gramicidin forming a beta 6.3 single-strand helix that is oriented parallel to the methylene chains of the lipid molecules. Comparison of the linewidths from labeled residues that are in the innermost turn of the helix (gly2, ala3, and D-leu4), in the center of the molecule (val7), and in the turn nearest the lipid bilayer surface (D-leu10, D-leu12, and D-leu14) suggests that although the peptide behaves largely as a rigid barrel, segments of the peptide close to the membrane surface possess greater motional freedom. At temperatures above the gel-to-liquid crystalline transition temperature (Tc) the gramicidin molecules rotate, with a less than millisecond correlation time, about the bilayer normal: several degrees below Tc they become immobile on the NMR timescale, without change in the channel conformation. In the L beta' phase the linewidths of the D-leu10, D-leu'2, and D-leu" resonances become equal to those of the other labeled sites, indicating reduced but equivalent motion for all of the peptide carbonyl groups.

Amino Acid Sequence↗