Search PubMed⌕ Search

Biomedical subjects

A Golay

Publications and source records attributed to A Golay.

At least 55 records · Page 3Linked to original sources
PubMed2000

Insulin resistance, lipid and fatty acid concentrations in 867 healthy Europeans. European Group for the Study of Insulin Resistance (EGIR).

BACKGROUND: Insulin resistance, dyslipidaemia and abnormal nonesterified fatty acid (NEFA) metabolism are features of the 'metabolic syndrome', but the mechanisms of these relationships are uncertain. MATERIALS AND METHODS: We studied associations between insulin resistance and lipoprotein concentrations by retrospective analysis of euglycaemic hyperinsulinaemic clamp data from 867 normoglycaemic subjects in 21 European centres. Data on NEFA concentrations were available in a subgroup of 541 subjects from 9 clinical centres. These subjects' characteristics do not vary significantly from those of the whole cohort. RESULTS: After adjustment for the effects of age, sex, obesity and intercentre variability, regression analysis showed relationships between triglycerides and markers of insulin sensitivity. There were significant correlations between triglycerides and fasting plasma glucose (P < 0.0001), fasting plasma insulin (P < 0.0001) and mean glucose infusion rate at steady state (M-value, P < 0.0001). Indices of insulin resistance were related to NEFA concentrations. Fasting NEFA were negatively correlated with the M-value (P < 0.0001). Non-esterified fatty acids at steady state were positively correlated with fasting markers of insulin resistance: fasting plasma glucose (P < 0.05), fasting plasma insulin (P < 0.005) and negatively correlated with the M-value (P < 0.0005). There were relationships between fasting concentrations of plasma lipids and of NEFAs. Non-esterified fatty acids at steady state correlated with fasting triglycerides (P < 0.0001), but not with any of the other plasma lipoprotein concentrations. The associations of fasting triglycerides with the M-value and with NEFAs at steady state were independent of each other. All these associations were independent of obesity and geographical location CONCLUSION: The results in this large cohort of healthy European subjects suggest that triglyceride concentrations depend upon both insulin's gluco-regulation (estimated by glucose uptake) and antilipolytic insulin action (measured by NEFA levels) during an euglycaemic clamp.

Adolescent↗
PubMed2000

Acute hyperinsulinemia and very-low-density and low-density lipoprotein subfractions in obese subjects.

BACKGROUND: The influence of hyperinsulinemia on concentrations of lipoprotein subfractions in obese, nondiabetic persons has not been clarified. OBJECTIVE: We analyzed VLDL and LDL subfractions before and after a euglycemic, hyperinsulinemic clamp. DESIGN: Lipoprotein subfractions were isolated from plasma samples obtained in the basal state and after a 4-h clamp from obese patients, obese patients with type 2 diabetes, and nonobese control subjects. RESULTS: Hyperinsulinemia tended to reduce concentrations (&xmacr;: 20%) of large, triacylglycerol-rich VLDL(1) in obese patients but had a minor effect on VLDL(2) and VLDL(3). Placing obese patients into insulin-sensitive and insulin-resistant subgroups revealed distinct effects of the degree of insulin sensitivity on VLDL. VLDL(1) concentrations decreased by a mean of 38% (P < 0.05) in insulin-sensitive patients after the clamp, similar to but less marked than the decrease observed in control subjects (&xmacr;: 62%; P < 0.01). VLDL(1) concentrations did not change significantly after the clamp in insulin-resistant patients (and patients with type 2 diabetes), whereas VLDL(3) concentrations decreased in both groups, in contrast with the changes seen in the insulin-sensitive patients and control subjects. Acute hyperinsulinemia modified the LDL subfraction profile toward a greater prevalence of small, dense LDLs in insulin-resistant patients and patients with type 2 diabetes. CONCLUSIONS: Insulin resistance appears to be the primary determinant of the modifications to VLDL subfraction concentrations. Our results suggest a continuum of impaired insulin action on VLDL, ranging from that in healthy persons to that in patients with type 2 diabetes, in which obese patients occupy a transition state. Insulin resistance may also play a role in detrimental modifications to the LDL profile by allowing the development of hypertriglyceridemia.

Adult↗
PubMed2000

Energy economy hampers body weight loss after gastric bypass.

The impact of energy economy on body weight loss was investigated in 20 obese women, submitted to Roux-en-Y gastric bypass. Resting energy expenditure (REE), substrate oxidation rates, plasma glucose, free fatty acid, and insulin and leptin levels were measured before and 3, 6, and 12 months after surgery. Predicted REE was obtained from linear regression analysis of REE and fat free mass, in a group of 85 women, whose body mass index ranged between 20 and 60 kg/m(2). The deviation from predicted REE, calculated as area under the curve (AUC) over the 12-month period for each patient, was considered as the expression of energy economy. Energy economy AUC was significantly (P: < 0.005) negatively related to the weight lost during 12 months after surgery. Energy intake, calculated from self-reported food consumption, was also expressed as AUC. Energy intake AUC showed a significant (P: < 0.002) positive correlation with weight loss. Lipid oxidation rate, also calculated as AUC, significantly correlated, negatively, with energy economy (P: < 0. 001) and, positively, with energy intake (P: < 0.002). Preoperative leptin values were significantly (P: < 0.01) linked to individual energy economy capacity. In conclusion, after Roux-en-Y gastric bypass, energy economy hampers the weight loss process, probably through a low fat oxidation rate.

Adult↗
PubMed2000

[Randomized placebo-controlled trial of orlistat for weight loss and prevention of weight regain in obese patients].

BACKGROUND: We undertook a randomised controlled trial to assess the efficacy and tolerance of orlistat, a gastrointestinal lipase inhibitor, in promoting weight loss and preventing weight regain in obese patients over a 2-year period. METHODS: 743 patients (body-mass index 28-47 kg/m2), recruited at 15 European centres, entered a 4-week, single-blind, placebo lead-in period on a slightly hypocaloric diet (600 kcal/day deficit). 688 patients who completed the lead-in were assigned double-blind treatment with orlistat 120 mg (three times a day) or placebo for 1 year in conjunction with the hypocaloric diet. In a second 52-week double-blind period patients were reassigned orlistat or placebo with a weight maintenance (eucaloric) diet. FINDINGS: From the start of lead-in to the end of year 1, the orlistat group lost, on average, more bodyweight than the placebo group (10.2% [10.3 kg] vs 6.1% [6.1 kg]; LSM difference 3.9 kg [p < 0.001] from randomisation to the end of year 1). During year 2, patients who continued with orlistat regained, on average, half as much weight as those patients switched to placebo (p < 0.001). Patients switched from placebo to orlistat lost an additional 0.9 kg during year 2, compared with a mean regain of 2.5 kg in patients who continued on placebo (p < 0.001). Total cholesterol, low-density lipoprotein (LDL) cholesterol, LDL/high-density lipoprotein ratio, and concentrations of glucose and insulin decreased more in the orlistat group than in the placebo group. Gastrointestinal adverse events were more common in the orlistat group. Other adverse symptoms occurred at a similar frequency during both treatments. INTERPRETATION: Orlistat taken with an appropriate diet promotes clinically significant weight loss and reduces weight regain in obese patients over a 2-year period. The use of orlistat beyond 2 years needs careful monitoring with respect to efficacy and adverse events.

Adolescent↗
PubMed1999

Beneficial effect of hormone replacement therapy on weight loss in obese menopausal women.

OBJECTIVE: At the onset of menopause, weight-gain and the aggravation of certain cardiovascular risk factors are frequently observed. The aim of this study was to examine the metabolic effects of combined hormone replacement therapy (17beta-oestradiol transdermic 50 microg for 21 days and oral medroxyprogesterone acetate 5 mg from day 10 to 21) using, in particular, indirect calorimetry. METHODS: Patients (21; 12 substituted and nine controls) were studied twice (3 months apart) during an oral glucose load (75 g). RESULTS: Total body weight was unaltered after 3 months in the control group, whereas a fat-loss of 2.1+/-0.2 kg and a decrease of the waist:hip ratio were observed in the substituted group. In the latter group, a significant increase in lipid oxidation was observed (0.58+/-0.06 mg/kg/min before and 0.75+/-0.04 mg/kg/min after substitution P<0.05), whilst total energy expenditure and thermogenesis were also increased. Glucose, lipid and protein oxidation remained stable during three months in the control group. The insulin response to an oral glucose load diminished by 30% with hormone replacement therapy (102.3+/-32.8 mmicro/l versus 71.4+/-20.0 mmicro/l). Total and LDL-cholesterol improved after hormone replacement therapy whereas plasma triglycerides were not altered. CONCLUSIONS: Combined hormone replacement therapy not only prevented weight-gain, but favored weight-loss by significantly increasing lipid oxidation after 3 months of treatment. It also favourably influenced the insulin response, plasma lipids and energy expenditure.

Cholesterol↗
PubMed1999

A new approach for patient education: beyond constructivism.

Over the last ten years, research developed in science education, especially at the University of Geneva, has demonstrated that education must be centered on interactions between the learner's conceptions and a systemic educational environment. Transposed to a medical knowledge, this new model, originally conceived by the authors and called the 'allosteric learning model', offers new ways of considering patient education. After criticizing the 'grand theories' of learning, mainly the latest ones called constructivist models, the authors suggest a new set of micromodels designed to explain thoroughly the functioning of the patient's thought process (questions, frame of references, semantic network,...) and his understanding of medical information on his own disease. For health care providers, these models also offer a series of new pedagogical approaches both efficient and original to regulate the act of education based on confrontation, mobilisation, integration, etc.

Attitude to Health↗
PubMed1999

Leptin plasma levels as a marker of sparing-energy mechanisms in obese women.

OBJECTIVE: To investigate possible relationships between leptin and energy expenditure (EE), both in the condition of stable body weight and during weight loss. SUBJECTS: Seventy four Caucasian, adult obese women with stable body weight (including 10 obese women studied before and during a body weight-reducing program). MEASUREMENTS: Resting EE (REE) and substrate oxidation rates by indirect calorimetry; plasma leptin concentrations by radioimmunoassay (RIA). RESULTS: In conditions of stable body weight, leptin values showed a significant, negative relationship with REE, as expressed in absolute values (P = 0.030) and as adjusted for the variation in lean body mass (LBM) (P = 0.017). This negative relationship was independent of both LBM and fat mass (FM). Linear regression analysis was used to obtain the equation linking REE and LBM; then both predicted REE and the percent deviation from predicted REE were calculated for each subject. Leptin values were negatively related (P < 0.0001) to the deviation from predicted REE. During active body weight loss, the modifications of both REE (delta REE) and lipid oxidation (delta lipid oxidation) were significantly negatively related to leptin concentrations, which were measured before the dieting period (P < 0.03 for both). CONCLUSION: In obese women, high plasma leptin concentrations are associated with a low rate of REE, when body weight is stable, and with a reduction of REE and lipid oxidation, in response to a hypocaloric diet. This suggests that, in severely obese women, leptin is a marker of sparing energy mechanisms operating in both basal and reducing weight conditions.

Biomarkers↗
PubMed1999

Metformin treatment leads to an increase in basal, but not insulin-stimulated, glucose disposal in obese patients with impaired glucose tolerance.

AIMS: This study was initiated to test the hypothesis that metformin treatment leads to enhanced glucose disposal at ambient insulin concentrations. METHODS: Nineteen obese patients with impaired glucose tolerance (IGT) were treated with either metformin or placebo in a randomized, double-blind, placebo-controlled, cross-over study. Insulin secretion and insulin resistance were quantified using the homeostasis model assessment (HOMA) and insulin-stimulated glucose disposal were measured by determining the steady-state plasma glucose (SSPG). RESULTS: The average benefit of metformin was 0.6 mmol/l for glucose (95% confidence interval (CI) 0.2-0.9 P = 0.002), 2.8 pmol/l for insulin (95% CI 0.2-5.4, P = 0.019). Insulin resistance, as quantified by HOMA, was improved by 1.1 (95% CI 0.2-2.0, P = 0.004), without any change in insulin secretion. Basal and insulin-stimulated glucose oxidation were comparable in the placebo and metformin-treated groups at the end of each treatment period, as was the SSPG concentration. However, both systolic and diastolic blood pressures fell significantly following metformin administration as compared to treatment with placebo. CONCLUSIONS: These results indicate that metformin administration to patients with IGT is associated with enhanced glucose disposal at baseline insulin concentrations and a fall in blood pressure. In contrast, neither glucose oxidation nor glucose disposal were increased in association with metformin treatment under conditions of physiological hyperinsulinaemia.

Blood Glucose↗
PubMed1998

Randomised placebo-controlled trial of orlistat for weight loss and prevention of weight regain in obese patients. European Multicentre Orlistat Study Group.

BACKGROUND: We undertook a randomised controlled trial to assess the efficacy and tolerability of orlistat, a gastrointestinal lipase inhibitor, in promoting weight loss and preventing weight regain in obese patients over a 2-year period. METHODS: 743 patients (body-mass index 28-47 kg/m2), recruited at 15 European centres, entered a 4-week, single-blind, placebo lead-in period on a slightly hypocaloric diet (600 kcal/day deficit). 688 patients who completed the lead-in were assigned double-blind treatment with orlistat 120 mg (three times a day) or placebo for 1 year in conjunction with the hypocaloric diet. In a second 52-week double-blind period patients were reassigned orlistat or placebo with a weight maintenance (eucaloric) diet. FINDINGS: From the start of lead-in to the end of year 1, the orlistat group lost, on average, more bodyweight than the placebo group (10.2% [10.3 kg] vs 6.1% [6.1 kg]; LSM difference 3.9 kg [p<0.001] from randomisation to the end of year 1). During year 2, patients who continued with orlistat regained, on average, half as much weight as those patients switched to placebo (p<0.001). Patients switched from placebo to orlistat lost an additional 0.9 kg during year 2, compared with a mean regain of 2.5 kg in patients who continued on placebo (p<0.001). Total cholesterol, low-density lipoprotein (LDL) cholesterol, LDL/high-density lipoprotein ratio, and concentrations of glucose and insulin decreased more in the orlistat group than in the placebo group. Gastrointestinal adverse events were more common in the orlistat group. Other adverse symptoms occurred at a similar frequency during both treatments. INTERPRETATION: Orlistat taken with an appropriate diet promotes clinically significant weight loss and reduces weight regain in obese patients over a 2-year period. The use of orlistat beyond 2 years needs careful monitoring with respect to efficacy and adverse events.

Adult↗
PubMed1998

Contrast sensitivity in obese dyslipidemic patients with insulin resistance.

OBJECTIVE: To evaluate contrast sensitivity in insulin-resistant obese patients and in aretinopathic diabetic patients. METHODS: Contrast sensitivity was measured at 3 letter sizes (44 x 44, 9 x 9, and 5 x 5 mm) in mesopic (5 candela [cd]/m2) and low photopic (85 cd/m2) vision in 20 dyslipidemic obese patients with insulin resistance, 20 age-matched patients with type 2 diabetes mellitus, and 20 aged-matched healthy control subjects. RESULTS: Significant loss of contrast sensitivity at all 3 letter sizes was observed in low photopic vision (at 44 x 44-mm letter size, control vs obese, P<.002, and control vs diabetic, P<.005; at 9 x 9-mm letter size, control vs obese, P<.02, and control vs diabetic, P<.001; and at 5 x 5-mm letter size, control vs obese, P<.05, and control vs diabetic, P<.005) and mesopic vision (at 44 x 44-mm letter size, control vs diabetic, P<.005; at 9 x 9-mm letter size, control vs obese, P<.005, and control vs diabetic, P<.01; and at 5 x 5-mm letter size, control vs obese, P<.005, and control vs diabetic, P<.001) in insulin-resistant obese and diabetic patients. CONCLUSION: The results suggest that an early neurosensory dysfunction may occur without visible vascular involvement and without overt hyperglycemia.

Adult↗
PubMed1998

Qualitative evaluation of courses intended for patients suffering from chronic diseases. New observation method for the continuous training of the healthcare team.

Experience has shown that when teaching patients, healthcare providers concentrate more on information concerning the illness rather than on the handling of treatment. Therapeutic education of patients imposes a precise structure on the pedagogic method and teaching aids. It is essential that, during their clinical practice, care-providers develop teaching methods which encourage a maximum of interaction to help patients learn to manage their own treatment. In this perspective, the authors propose 'analytical observation' as a method of training evaluation for healthcare providers. Three observation charts, as well as an analytical method for evaluation, have been devised. They have been tried and validated during a study whose principal objective was to measure quantitatively the impact of supervision of care-providers in the domain of therapeutic education of patients. The authors conclude that this method has a definite impact on the pedagogic progress of the care-providers. It makes it possible to record and to give a structure to the pedagogic follow-up (inspection, examination, testing) of care-providers. Since patient education plays a key role in therapeutic success, this type of methodology for training and evaluation conforms to the rigorousness essential to any therapeutic undertaking.

Chronic Disease↗
PubMed1997

Personalities and alimentary behaviors in obese patients.

The actual tendency in the care of obese patients is the association of dietetic information with an eating behavior therapy. Studies attempting to attribute the origin of obesity to psychiatric pathologies are contradictory. We studied whether certain eating disorders are more specific to a personality type. We studied eating disorders with the Eating Disorder Inventory (EDI) test in 281 obese women compared to 252 age-matched non-obese women. Both obese patients and non-obese volunteers were divided into four groups depending upon their personality (PERSONA test). This test defines four types of personality, based on the level of emotion (expansive or reserved) and the degree of power (dominant or consenting). According to our study, eating disorders vary between the four personality groups and were significantly higher in the facilitating group (consenting and expansive) compared to the three other obese groups. Neither promoting (expansive and dominant) nor controlling obese patients (dominant and reserved) present eating disorders. The analyzing obese patients (reserved and consenting) are reticent when it comes to consulting (18%) since they distrust others. Analyzing obese patients present an interpersonal distrust and an interoceptive awareness. The group which presents most eating disorders is that of facilitating obese patients (consenting and expansive). These present eating disorders of the compulsive types favored by interoceptive awareness, body dissatisfaction, ineffectiveness, and maturity fears. The diversity, even the absence, of eating disorders brought to evidence by our tests based upon different personality types should allow better understanding of the psychological and behavioral causes of weight gain and the means for improving compliance in the following of an obese patient.

Adult↗
PubMed1997

Energy expenditure and substrates oxidative patterns, after glucose, fat or mixed load in normal weight subjects.

OBJECTIVES: To evaluate energy balance after three isocaloric oral loads of different composition and to establish possible relationships between the substrates oxidative patterns and the modifications of insulin and free fatty acids (FFA) plasma profiles. DESIGN: Each subject received, in a randomized order, three oral loads of 2658 +/- 45 kJ (636 +/- 11 Kcal) either as glucose, lipids (cream) or a mixture (glucose+cream). SETTING: The experiments were performed at the University Hospital of Geneva. SUBJECTS: Ten normal body-weight volunteers. METHODS: Energy expenditure (EE) and substrates oxidation were measured by indirect calorimetry during 8 h following each load. Plasma glucose, insulin and FFA were also measured. RESULTS: EE was 1776 +/- 107, 1818 +/- 125 and 1785 +/- 117 KJ over 8 h after glucose, mixed and lipids load, respectively. Glucose oxidation was the highest after oral glucose as compared to mixed and lipids load, while the highest value of lipids oxidation was measured after fat load. A significant relationship linked fat oxidation to plasma FFA (r = 0.54, P < 0.002) as well as to insulin (r = -0.40, P < 0.002). CONCLUSIONS: (a) The energetic cost of glucose and fat intake is the same; (2) after each load, the main source of energy corresponds to the substrate administered; (3) both plasma insulin and FFA influence the substrate oxidative patterns observed after each load; (4) alimentary fat may contribute to fat oxidation by maintaining elevated plasma FFA levels.

Aged↗
PubMed1997

Lipoprotein distribution and composition in obesity: their association with central adiposity.

OBJECTIVE: To examine the relationships between the distribution and composition of subfractions of very low density (VLDL), low density (LDL) and high density (HDL) lipoproteins and central fat deposition as measured by the waist-to-hip ratio (WHR). DESIGN: Participants (n = 62, 44 women and 18 men; body mass index (BMI) > or = 25.0) were recruited from those consecutively attending the outpatient obesity clinic at the University Hospital, Geneva. MEASUREMENTS: Lipoprotein subfractions were isolated from fasting blood samples by cumulative flotation or density gradient ultracentrifugation. Concentration and composition were analysed as a function of obesity indices. RESULTS: There were significant correlations between the WHR and the profiles of the three major lipoprotein subclasses. Central obesity was associated with larger VLDL, small, dense LDL and lower levels of HDL-2 independently of other indices of obesity and plasma triglycerides. Central obesity was also significantly and independently associated with compositional anomalies, specifically an increased free cholesterol content of VLDL and LDL. CONCLUSIONS: Central body fat was associated with modifications of an atherogenic nature to lipoprotein distribution and composition. The data are consistent with an impact of body fat distribution on cardiovascular disease (CVD) via the agency of modified lipoprotein metabolism independently of raised triglycerides.

Adolescent↗