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Biomedical subjects

F X Pi-Sunyer

Publications and source records attributed to F X Pi-Sunyer.

At least 73 records · Page 4Linked to original sources
PubMed1995

Insulin resistance in adipocytes of obese women: effects of body fat distribution and race.

Upper-body obesity (UBO) in white women is associated with increased fatty acid turnover and resistance to the effects of insulin on systemic glucose metabolism. The present study determined whether the abilities of insulin to stimulate glucose transport and suppress lipolysis are impaired in adipocytes from white UBO (W-UBO) women. Because the clinical risks associated with UBO are attenuated in black women, the effects of race on adipocyte insulin sensitivity were assessed. Forty-two healthy, equally obese women were selected for study on the basis of race (black or white) and body fat distribution (UBO or lower-body obesity [LBO]). In white women, both abdominal and gluteal fat cells from the UBO versus LBO group were less responsive to the stimulatory effects of insulin on glucose uptake and less sensitive to the antilipolytic effects of insulin and the adenosine analog, phenylisopropyladenosine (PIA). In contrast, in black women, fat cells from UBO and LBO groups were equally sensitive to the stimulatory effects of insulin on glucose transport and the suppressive effects of insulin and PIA on lipolysis. These in vitro data correlate well with previous clinical findings that UBO in white women but not in black women is associated with insulin resistance and dyslipidemia. Thus, resistance to the antilipolytic effects of insulin and adenosine at the level of adipose tissue may increase systemic lipolysis and play a role in the development or maintenance of peripheral insulin resistance associated with UBO in white women, but not in black women.

Abdomen↗
PubMed1995

The use of areas under curves in diabetes research.

Recently, several articles appearing in the diabetes literature have suggested that many investigators are unclear about a number of issues involving the use of areas under the curve (AUCs). This prompted us to reconsider issues in the calculation, use, meaning, and presentation of AUCs. We discuss five issues: 1) What is a curve and an area? 2) How should one graphically present a group's curve? 3) How should one calculate AUCs? 4) Should one subtract baseline values from outcome values before calculating AUCs? And 5) are AUCs the best way to combine multiple readings into a single index?

Analysis of Variance↗
PubMed1995

Is the intra-uterine period really a critical period for the development of adiposity?

OBJECTIVE: The intra-uterine environment may be a critical period for the development of adiposity. Alternatively, most of the co-variance of relative weight from birth to adulthood may be genetic in origin. This study tested whether birth weight 'tracks' into adulthood, independent of genetic factors. DESIGN: Observational twin study. Birth weights and gestational ages from birth records of 8040 twins from the Minnesota Twin Registry including 699 monozygotic (MZ) male pairs, 609 dizygotic (DZ) male pairs, 939 MZ female pairs, 880 DZ female pairs, and 893 opposite sex DZ pairs ages (yrs) 28 to 52 (Mean = 40.3; s.d. = 6.2) were compared to self-reported adult height and weight. RESULTS: The correlation of birth weight with adult height was 0.236, with adult weight 0.188, and with adult body mass index 0.078 (all P-values < 0.0005). To test if this tracking was independent of genetic influences, we analyzed intra-pair differences for MZ twins. If differences in birth weight between members of a MZ twin pair correlate with adult relative weight, this association cannot be attributed to genetic influences. The correlation of intra-pair differences in birth weight with intra-pair differences in adult height was 0.316 (P < 0.0005), with adult weight 0.136 (P < 0.0005), and with adult BMI 0.026 (P = 0.331). Results were unchanged when multivariate regression modeling was employed. CONCLUSION: These data suggest that the intra-uterine environmental influences on birth weight have an enduring impact on adult height but not on adult relative weight. This suggests that the intra-uterine period is a critical period for the development of height but not for adiposity.

Adipose Tissue↗
PubMed1994

Columbia respiratory-chamber indirect calorimeter: a new approach to air-flow modelling.

A new air-flow modelling approach for respiratory-chamber indirect calorimetry is introduced. Based on thermodynamic theory, differential equations describing the dynamics of the calorimeter are derived. These equations are then developed into a linear state space model that can be conceptualized as a modern control system. Furthermore, both the system/output noises and input/output delays are considered in the model in the context of real applications. Finally, system accuracy is analysed so that the parameters in the calorimeter can be selected to minimise the error in estimating energy expenditure in humans.

Basal Metabolism↗
PubMed1994

Effects of glucose and fructose solutions on food intake and gastric emptying in nonobese women.

The differential effects of fructose and glucose on food intake were studied by giving two concentrations (1 and 10%) of glucose and fructose solutions (500 ml) to one group of women 30 min, and to another 135 min, before a meal of macaroni and beef. The 1% solutions of each sugar were sweetened to match 10% fructose by selective additions of aspartame. Gastric emptying of the 10% solutions and water was measured for 90 min. Under the 30-min delay, subjects ate a mean of 75.8 g more (P < 0.05) after the 1% solutions than after water, and 52.2 g (P > 0.05) less after the 10% solutions than after water, but there were no differences in intake between types of sugar under either delay nor between concentrations at the 135-min delay. However, 10% fructose and 1% glucose sweetened to match it reduced intake significantly compared with water. Glucose (10%) emptied significantly slower (t1/2 = 93.61 min) than water (t1/2 = 29.77 min), while fructose (10%) was intermediate (t1/2 = 65.45 min). Therefore, gastric emptying differences did not account for these results. We conclude that sweetener-enhanced dilute sugar solutions may increase subsequent intake at 30 min, but dilute glucose solutions may have potential for substantial energy savings if consumed 135 min before a meal.

Adult↗
PubMed1994

Effects of the carbohydrase inhibitor miglitol in sulfonylurea-treated NIDDM patients.

OBJECTIVE: To examine the effects of the carbohydrase inhibitor miglitol (BAY m 1099) on the metabolic profiles of non-insulin-dependent diabetes mellitus (NIDDM) patients suboptimally controlled on maximal daily doses of sulfonylurea (SFU) agents. RESEARCH DESIGN AND METHODS: Multicenter, double-blind, randomized, placebo-controlled 14-week clinical trial with six-week, single-blind placebo lead-in and run-out periods. NIDDM volunteers (192) with fasting plasma glucose (FPG) 140-250 mg/dl and hemoglobin A1c (HbA1c) 6.5-12.0% after at least 4 weeks of treatment with SFU at maximal dose were stratified by baseline HbA1c (above and below 9.0%) and then randomly assigned within strata to placebo (n = 63), 50 mg miglitol 3 times a day (n = 61), or 100 mg miglitol 3 times a day (n = 68). Efficacy was assessed by HbA1c, FPG, insulin, and lipid concentrations, and by plasma glucose and serum insulin responses to a standard meal. RESULTS: In the 50 and 100 mg miglitol treatment groups, the mean changes from baseline in HbA1c (with placebo values subtracted) were 0.82 and 0.74%, respectively, and were highly significant (P = 0.0001 in each case). Mean peak plasma glucose levels after a standard test meal were comparably lowered by 57 mg/dl with the 50 mg miglitol dose, and by 64 mg/dl with the 100 mg miglitol dose compared with placebo (P = 0.0001 for each), with associated reductions in integrated serum insulin response (P < 0.05). No significant drug-associated changes in FPG, insulin, or cholesterol levels were noted, but fasting triglyceride levels were lowered significantly with the 50 mg miglitol dose. Miglitol's side effects were limited to flatulence, loose stools, and abdominal discomfort, which were dose-related, rapidly resolved on drug discontinuation, and led to withdrawal from the study of 5 and 15% of patients taking 50 and 100 mg miglitol, respectively. CONCLUSIONS: Miglitol may be indicated as effective adjuvant therapy in NIDDM patients with suboptimal metabolic control despite conventional treatment with diet and maximal daily doses of SFU. The dose of 50 mg miglitol 3 times a day may be preferable to 100 mg miglitol 3 times a day because of comparable efficacy and substantially reduced side effects.

1-Deoxynojirimycin↗
PubMed1993

Medical hazards of obesity.

The medical hazards of obesity are discussed. Risks include insulin resistance, diabetes mellitus, hypertriglyceridemia, decreased levels of high-density lipoprotein cholesterol, and increased levels of low-density lipoprotein cholesterol. Obesity is also associated with gallbladder disease and some forms of cancer as well as sleep apnea, chronic hypoxia and hypercapnia, and degenerative joint disease. Obesity is an independent risk factor for death from coronary heart disease. A central distribution of body fat enhances the risk for most of these conditions.

Humans↗
PubMed1993

Short-term medical benefits and adverse effects of weight loss.

Weight loss reduces many of the health hazards associated with obesity including insulin resistance, diabetes mellitus, hypertension, dyslipidemia, sleep apnea, hypoxemia and hypercarbia, and osteoarthritis. Potential adverse effects of weight loss include a greater risk for gallstone formation and cholecystitis, excessive loss of lean body mass, water and electrolyte problems, mild liver dysfunction, and elevated uric acid levels. Less consequential problems such as diarrhea, constipation, hair loss, and cold intolerance may also occur. The short-term adverse effects are not severe enough to contraindicate weight loss, nor do they outweigh its short-term benefits.

Diet, Reducing↗
PubMed1993

Metabolic efficiency of macronutrient utilization in humans.

Macronutrient utilization in humans is a complex phenomenon, with each macronutrient having its separate storage and utilization pathways. Carbohydrate and fat are to some extent interdependent, but while carbohydrate utilization is greatly dependent on intake, fat is not. The food quotient of the diet is important in determining how nutrients are utilized and stored, and thus is an important determinant of body composition. Also, the effect of these two macronutrients on food intake differs. The bioenergetics of utilization of the macronutrients are discussed.

Body Composition↗
PubMed1993

Intravenous infusion of bombesin reduces food intake in humans.

Infusion of bombesin into healthy young men at two dosages (1.33 and 4.0 ng.kg-1.min-1) resulted in a significant 135-g reduction in intake of a yogurt and fruit blend, compared with saline infusions, at the higher dose, but only a 20-g (nonsignificant) reduction at the lower dose. There were no overt side effects, although half of the subjects reported a slightly elevated (mean elevation = 0.5 on a 1-5 category scale) sick sensation when receiving bombesin at the higher dose, but not when receiving saline. At the higher dose, the mean palatability of the test meal was reduced by 0.5 units on a nine-point scale of liking. This study demonstrates for the first time in humans that a slow intravenous infusion of bombesin can decrease spontaneous food intake when infused at the rate of 4 ng.kg-1.min-1 beginning at the onset of a meal. These results confirm that the short-term satiety effect of peripherally administered bombesin previously reported in animals can be obtained in humans.

Bombesin↗
PubMed1993

Race-dependent health risks of upper body obesity.

For Caucasian women, an excess of abdominal fat is a potent risk factor for the development of diabetes and cardiovascular disease. However, there is limited information regarding the health risks of upper body obesity for African-American women despite a higher prevalence of obesity and obesity-related diseases and a reportedly higher prevalence of abdominal fat accumulation. This study aimed to determine whether UBO, independent of total body fatness, is as potent a diabetic and CVD risk factor for black women as has been confirmed for white women. Diabetes and CVD risks and androgenic status were assessed in nondiabetic, premenopausal women of similar body fatness who differed by race (black or white) and body fat distribution (UBO or lower body obesity). In black women, high-density lipoprotein cholesterol was the only measurement adversely affected by abdominal fat; HDL cholesterol was significantly lower in the black UBO group (1.14 +/- 0.05 mM) compared with the black LBO group (1.37 +/- 0.08 mM). This contrasts markedly with our findings in white women. In confirmation of previous reports, white UBO women, compared with white LBO counterparts, had significantly higher glucose (967.6 vs. 709.2 mM/2 h) and insulin (120.5 vs. 52.1 pM/2 h) areas and significantly lower peripheral insulin sensitivities (0.99 vs. 2.95 x 10(-4) min-1/microU/ml). In addition, HDL cholesterol levels were significantly lower in the white UBO group (1.03 mM) compared with the white LBO group (1.49 mM), whereas plasma TG levels (white UBO, 1.72 vs. white LBO, 0.88 mM) and dBPs (white UBO, 84 vs. white LBO, 75 mmHg) were significantly higher.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1992

Composition of weight loss in severely obese women: a new look at old methods.

Seven severely obese, outpatient dieters lost weight (mean +/- SEM, 14 +/- 1 kg), and the composition of weight lost was determined by six different models. Total body water (TBW), total body potassium (TBK), and body density, bone mineral content, and fat as determined by dual photon absorptiometry (DPA) were measured while subjects were weight-stable, before and after weight loss. Fat loss was calculated by three two-compartment models (2C-TBW, 2C-TBK, and hydrodensitometry [2C-HD]), one three-compartment model (HD with correction for water content of fat-free mass [FFM], 3C), and one four-compartment model (HD with correction for water and mineral content of FFM, 4C), and was measured directly by DPA. Mean composition of weight loss was similar for all models (mean weight lost as fat: 89% for DPA, 91.5% for 4C, 89% for 3C, 88.6% for 2C-HD, and 87% for 2C-TBW) except 2C-TBK (weight lost as fat, 66%). There was a much wider range of individual values for the 2C-TBW and 2C-TBK models (17% to 138% and 18% to 93%, respectively) than for the multicompartment models (63% to 112%) and DPA (76% to 107%). Almost opposite results were obtained for the same individual when using the 2C-TBK and 2C-TBW models. The discrepancy between these models was due to the inverse relationship between changes in TBW and TBK in the group as a whole (r = -.34, NS). In addition, TBK loss was found to be dependent on the initial level of hyperinsulinemia, calculated as the area under the 2-hour oral glucose tolerance curve.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1992

The role of very-low-calorie diets in obesity.

The popularity of very-low-calorie diets (VLCDs) is enormous, but questions persist about their safety and their long-term efficacy. This article addresses the following questions: who should be placed on a VLCD? when should a patient go on a VLCD? how much should an individual lose? where should a VLCD program be carried out and by whom? It stresses the importance of evaluating VLCD programs by their long-term goals and long-term results. Also, a few of the unanswered questions in VLCD treatment are addressed. Finally, worrisome financial-ethical questions of the business of VLCDs is discussed.

Adipose Tissue↗