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1.
Horm Metab Res ; 48(8): 497-502, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26882050

RESUMEN

The purpose of this study was to compare plasma 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH), VO2max, bone (by DXA), and metabolic outcomes across age and race-matched postmenopausal women (54±1 years; mean±SEM): 1) with previous gestational diabetes (GDM) (32±1 kg/m(2); n=17), 2) without previous GDM, but with a similar BMI to GDM (32±1 kg/m(2); n=17), and 3) without previous GDM, but with a higher BMI than GDM (36±1 kg/m(2); n=17; p<0.01). The prevalence of 25(OH)D insufficiency and deficiency was high (~80%), but not different across groups, while PTH tended to be ~30% lower in women with a history of GDM (p=0.09). Women with a history of GDM had lower HDL cholesterol and higher diastolic blood pressure and fasting and 2-h glucose levels (by oral glucose tolerance test) (vs. groups 2 and 3; p<0.05). Bone mineral density (BMD) tended to be slightly higher in women with prior GDM than the BMI matched women with no prior GDM (p=0.09). Overall, higher PTH was associated with lower femoral neck (r=- 0.33) and (r=- 0.38) (p <0.05), while lower 25(OH)D was associated with lower VO2max (r=0.25, p=0.05) and higher fasting glucose (r=- 0.14) and insulin (r=- 0.29 (p <0.05). We observed that the poor metabolic profiles of postmenopausal women with a history of GDM are independent of 25(OH)D and PTH. However, due to associations between 25(OH)D and PTH with bone and metabolic outcomes, maintaining recommended 25(OH)D and PTH concentrations is important regardless of a previous history of GDM.


Asunto(s)
Huesos/metabolismo , Diabetes Gestacional/sangre , Diabetes Gestacional/metabolismo , Hormona Paratiroidea/sangre , Vitamina D/análogos & derivados , Adulto , Anciano , Femenino , Humanos , Resistencia a la Insulina , Vértebras Lumbares/patología , Persona de Mediana Edad , Embarazo , Análisis de Regresión , Factores de Riesgo , Vitamina D/sangre
2.
J Org Chem ; 81(3): 787-802, 2016 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-26735748

RESUMEN

We report the first example of a very general Cu-catalyzed cross-coupling of organoaluminum reagents with organohalides. The reactions proceed for the couplings of alkyl-, aryl-, and alkynylaluminum reagents with aryl and heteroaryl halides and vinyl bromides, affording the cross-coupled products in good to excellent yields. Both primary and secondary alkylaluminum reagents can be utilized as organometallic coupling partners. These reactions are not complicated by ß-hydride elimination, and as a result rearranged products are not observed with secondary alkylaluminum reagents even for couplings with heteroaryl halides under "ligand-free" conditions. Radical clock experiment with a radical probe and relative reactivity study of Ph3Al with two haloarenes, 1-bromonaphthalene and 4-chlorobenzonitrile, having two different redox potentials indicates that the reaction does not involve free aryl radicals and radical anions as intermediates. These results combined with the result of the Hammett plot obtained by reacting Ph3Al with iodoarenes containing p-H, p-Me, p-F, and p-CF3 substituents, which shows a linear curve (R(2) = 0.99) with a ρ value of +1.06, suggest that the current transformation follows an oxidative addition-reductive elimination pathway.

3.
J Frailty Aging ; 12(1): 49-58, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36629084

RESUMEN

The People aged 50 years and above comprise over 50% of people living with HIV (PLWH) in the US. Despite the advances made with anti-retroviral therapy in increasing their life span, PLWH are plagued with non-AIDS associated conditions which increase their risk for morbidity and mortality. Frailty, a decline in physical and functional reserve, is one of the manifestations of aging, has a prevalence of 5-30%, and occurs up to 2 decades earlier in people aging with HIV (PAWH). The majority of providers for PAWH have minimal experience with the concept of gerontology, frailty, and aging. Hence, there is a gap in clinicians' knowledge on how to address frailty and aging in PAWH. This review will focus on the clinical interventions that mitigate frailty and aging in PAWH as well as highlight areas of investigation towards achieving these mediations. Beyond the identification of the roles of exercise and nutrition, more studies are needed on the pragmatic approach to apply these resources to routine care. There should be continued reinforcement of the proven strategy of combination antiretroviral therapy as well as treatment of co-infections and age-appropriate health and cancer screening in PAWH.


Asunto(s)
Fragilidad , Geriatría , Infecciones por VIH , Humanos , Envejecimiento , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/epidemiología , Longevidad
4.
Biol Res Nurs ; 23(2): 218-222, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-32748635

RESUMEN

Interleukin 6 (IL-6) and its receptors are expressed in approximately half of breast cancer (BC) tissues, and high serum IL-6 levels are associated with poor prognosis. African American (AA) patients with BC have higher serum IL-6 levels compared to Caucasians, suggesting additional risk of disease-related complications in AAs. The purpose of this study was to compare IL-6 complex biomarkers in AA women with and without a history of BC. We conducted a secondary analysis of phenotypic data from two studies of weight loss in AA women with and without a history of BC who had similar age and adiposity. Biomarkers analyzed included tumor necrosis factor alpha (TNF-α), IL-6, IL-6 soluble receptor (IL6sr), and soluble glycoprotein 130 (GP130); IL6sr and GP130 were newly analyzed for this study. TNF-α levels were 1.86 times higher in the BC group (N = 7) compared to those without BC (N = 10; p < 0.001) despite similar age, weight, and body mass index. GP130 levels tended to be higher in women with BC; IL-6 and Il-6 sr were not different between groups. There was a strong correlation between GP130 and TNF-α (r = .638; p = .006) in the group overall. High TNF-α levels in the BC group and a strong correlation between GP130 and TNF-α in the overall group suggest the presence of IL-6 complex initiated TNF-α production. Further study is needed to evaluate IL-6 reduction through a variety of approaches, including weight loss and anti-IL-6 therapies, which may ultimately implicate the reduction of IL-6 complex associated BC-specific recurrence and mortality.


Asunto(s)
Negro o Afroamericano/estadística & datos numéricos , Neoplasias de la Mama/sangre , Interleucina-6/sangre , Sobrepeso/sangre , Receptores de Interleucina-6/sangre , Adulto , Biomarcadores/sangre , Neoplasias de la Mama/etnología , Femenino , Glicoproteínas/sangre , Humanos , Persona de Mediana Edad , Obesidad/sangre , Obesidad/etnología , Sobrepeso/etnología , Factor de Necrosis Tumoral alfa/sangre
5.
J Frailty Aging ; 9(3): 134-138, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32588026

RESUMEN

BACKGROUND: High levels of intramuscular adipose tissue and low levels of capillarization are both predicative of low muscle and mobility function in older adults, however little is known about their relationship. OBJECTIVES: The purpose of this study was to examine the relationship of intramuscular adipose tissue and capillarization in older adults. SETTING: An outpatient medical center. PARTICIPANTS: Forty-seven sedentary adults (age 59.9 ± 1.0 years, BMI 32.0 ± 0.7 kg/m2, VO2max 22.4 ± 0.7 ml/kg/min); Measurements: All participants underwent CT scans to determine intramuscular adipose tissue and muscle biopsies to determine capillarization in the mid-thigh. A step-wise hierarchical linear regression analysis was used to examine the contributions of age, sex, race, body mass index, 2-hour postprandial glucose, VO2max, and muscle capillarization, to the variability in intramuscular adipose tissue. RESULTS: The predictors as a group accounted for 38.1% of the variance in intramuscular adipose tissue, with body mass index and capillarization each significantly contributing to the final model (P<0.001). The part correlation of body mass index with intramuscular adipose tissue was r = 0.47, and the part correlation of capillarization with intramuscular adipose tissue was r = 0.39, indicating that body mass index and capillarization explained 22.1%, and 15.2% of the variance in intramuscular adipose tissue. CONCLUSIONS: While increased muscle capillarization is typically thought of as a positive development, in some clinical conditions, such as tendinopathies, an increase in capillarization is part of the pathological process related to expansion of the extracellular matrix and fibrosis. This may also be an explanation for the surprising finding that high capillarization is related to high levels of intramuscular adipose tissue. Future studies are necessary to determine the relationship of changes in both capillarization and intramuscular adipose tissue after interventions, such as exercise.


Asunto(s)
Tejido Adiposo/metabolismo , Músculo Esquelético/irrigación sanguínea , Músculo Esquelético/metabolismo , Índice de Masa Corporal , Capilares/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Muslo/irrigación sanguínea
6.
Org Lett ; 22(8): 3268-3272, 2020 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-32237752

RESUMEN

We describe a novel method to synthesize 2,5-dialkyl-4,6,7-tricyanoindole derivatives from a base-catalyzed reaction of 1,3-diketones with fumaronitrile. The reaction proceeds by the condensation of two molecules of fumaronitrile and one molecule of 1,3-diketone in a remarkable process that involves the cleavage of one C(sp3)-C(sp2) bond in 1,3-diketones and the formation of one carbon-nitrogen bond and four carbon-carbon bonds to construct both the aryl and pyrrole rings of the indole in one step.

7.
Obes Sci Pract ; 3(1): 106-114, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-28392937

RESUMEN

OBJECTIVES: This study examines the hypothesis that lower adipose tissue lipoprotein lipase (LPL) activity and a limited capacity for subcutaneous adipocyte expansion will be associated with metabolic syndrome (MSyn) in postmenopausal women who are overweight and obese. METHODS: Women (N = 150; age 60 ± 1 year; BMI: 31.5 ± 0.3 kg m-2; mean ± standard errors of the means [SEM]) with and without MSyn had dual-energy X-ray absorptiometry scans for total body fat, CT scans for visceral and subcutaneous abdominal adipose tissue areas, lipid and glucose metabolic profiles, and abdominal and gluteal fat aspirations for subcutaneous fat cell weight (FCW; N = 150) and LPL activity (N = 100). RESULTS: Women with MSyn had similar total body fat, but 15% larger abdominal and 11% larger gluteal FCWs and more visceral fat (179 ± 7 vs. 134 ± 6 cm2) than women without MSyn (P's < 0.05). Abdominal LPL activity was 13% (P = 0.18) lower in women with than without MSyn and correlated with abdominal FCW (r = 0.49, P < 0.01) only in those without MSyn. Visceral fat and abdominal and gluteal FCWs correlated with MSyn components, and subcutaneous adipose tissue correlated with abdominal FCW (r = 0.43, P < 0.01) and LPL activity (r = 0.18, P < 0.05), independent of total body fat. CONCLUSIONS: These results show that women with MSyn have lower LPL activity, limited capacity for subcutaneous adipocyte lipid storage and greater ectopic fat accumulation in viscera than women without MSyn of comparable obesity. This suggests that the development of novel therapies that would enhance adipocyte expandability might prevent the accumulation of ectopic fat and reduce the risk for MSyn in postmenopausal women with obesity.

8.
Diabetes ; 50(9): 2172-6, 2001 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11522688

RESUMEN

This study determined the effects of the peroxisome proliferator-activated receptor (PPAR)-gamma2 Pro12Ala variant on body composition and metabolism and the magnitude of weight regain in 70 postmenopausal women (BMI 25-40 kg/m(2)) who completed 6 months of a hypocaloric diet. At baseline, BMI, percent body fat, intra-abdominal and subcutaneous abdominal fat areas, resting metabolic rate, substrate oxidation, and postprandial glucose and insulin responses were not different between genotypes (Pro/Pro = 56, Pro/Ala and Ala/Ala = 14). The intervention similarly decreased body weight by 8 +/- 1% in women homozygous for the Pro allele and by 7 +/- 1% in women with the Ala allele (P < 0.0001). Fat oxidation did not change in Pro/Pro women but decreased 19 +/- 9% in women with the Ala allele (P < 0.05). Changes in glucose area were not different between groups; however, women with the Ala allele decreased their insulin area more than women homozygous for the Pro allele (P < 0.05). Weight regain during follow-up was greater in women with the Ala allele than women homozygous for the Pro allele (5.4 +/- 0.9 vs. 2.8 +/- 0.4 kg, P < 0.01). PPAR-gamma2 genotype was the best predictor of weight regain (r = 0.50, P < 0.01), followed by the change in fat oxidation (partial r = 0.35, P < 0.05; cumulative r = 0.58). Thus, the Pro12Ala variant of the PPAR-gamma2 gene may influence susceptibility for obesity.


Asunto(s)
Variación Genética , Metabolismo/genética , Receptores Citoplasmáticos y Nucleares/genética , Factores de Transcripción/genética , Pérdida de Peso/fisiología , Secuencia de Aminoácidos/genética , Femenino , Predicción , Genotipo , Humanos , Persona de Mediana Edad
9.
Top Stroke Rehabil ; 12(1): 1-16, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15735997

RESUMEN

Stroke patients have profound cardiovascular and muscular deconditioning, with metabolic fitness levels that are about half those found in age-matched sedentary controls. Physical deconditioning, along with elevated energy demands of hemiparetic gait, define a detrimental combination termed diminished physiological fitness reserve that can greatly limit that can greatly limit performance of activities of daily living. The physiological features that underlie worsening metabolic fitness in the chronic phase of stroke include gross muscular atrophy, altered muscle molecular phenotype, increased intramuscular area fat, elevated tissue inflammatory markers, and diminished peripheral blood flow dynamics. Epidemiological evidence further suggests that the reduced cardiovascular fitness and secondary biological changes in muscle may propagate components of the metabolic syndrome, conferring added morbidity and mortality risk. This article reviews some of the consequences of poor fitness in chronic stroke and the potential biological underpinnings that support a rationale for more aggressive approaches to exercise therapy in this population.


Asunto(s)
Actividades Cotidianas , Sistema Cardiovascular , Prueba de Esfuerzo , Atrofia Muscular/diagnóstico , Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular/diagnóstico , Femenino , Humanos , Masculino , Atrofia Muscular/rehabilitación , Consumo de Oxígeno/fisiología , Resistencia Física/fisiología , Aptitud Física , Pronóstico , Medición de Riesgo , Índice de Severidad de la Enfermedad
10.
Diabetes Care ; 24(9): 1646-52, 2001 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11522714

RESUMEN

OBJECTIVE: The ACE insertion/deletion (I/D) polymorphism has been identified as a genetic risk factor for coronary heart disease (CHD). The deletion (D) allele of the ACE gene may be associated with higher insulin sensitivity. Individuals who are homozygous for the DD allele have higher ACE levels and possibly more angiotensin II, which, when infused exogenously, causes an increase in insulin sensitivity. The purpose of this study was to investigate the association of the I/D polymorphism of the ACE gene with insulin sensitivity and CHD risk factors. RESEARCH DESIGN AND METHODS: The study included 66 women (ages 57 +/- 1 years) who were overweight or obese (means +/- SEM, BMI = 33 +/- 1 kg/m(2)) and sedentary (VO(2max) = 19.6 +/- 0.4 ml. kg(-1). min(1)). Total body fat mass and percent fat were determined by dual-energy X-ray absorptiometry, and abdominal fat was by computed tomography. Insulin sensitivity was measured during the last 30 min of 3-h hyperinsulinemic-euglycemic clamps (40 mU. m(-2). min(-1)). Comparisons were made among women with the II (n = 9), ID (n = 36), and DD (n = 21) genotypes. RESULTS: Age, percent body fat, waist-to-hip ratio, visceral and subcutaneous abdominal fat areas, plasma lipid levels, and systolic and diastolic blood pressures did not differ by ACE genotype. Fasting glucose and 2-h glucose levels were similar among genotypes, but fasting plasma insulin levels were lower in DD women than in ID women (P < 0.05). Glucose utilization was higher in women with the DD genotype than in women with the II genotype (53.1 +/- 3.9 vs. 36.0 +/- 3.8 micromol. kg(-1) FFM. min(-1), P = 0.01) and was higher in ID women than in II women (48.5 +/- 2.5 micromol. kg(-1) FFM. min(-1), P = 0.04). CONCLUSIONS: These data suggest that the I/D polymorphism is not associated with risk factors for CHD in overweight sedentary women; however, women who are homozygous for the D allele of the ACE gene are more insulin sensitive, whereas women who are homozygous for the I allele of the ACE gene have greater insulin resistance and potential risk for type 2 diabetes.


Asunto(s)
Glucemia/metabolismo , Peso Corporal/genética , Insulina/sangre , Insulina/farmacología , Obesidad/genética , Peptidil-Dipeptidasa A/genética , Polimorfismo Genético , Absorciometría de Fotón , Tejido Adiposo/anatomía & histología , Adulto , Alelos , Glucemia/efectos de los fármacos , Presión Sanguínea , Composición Corporal , Constitución Corporal , Calorimetría Indirecta , Enfermedad Coronaria/genética , Elementos Transponibles de ADN , Femenino , Genotipo , Técnica de Clampeo de la Glucosa , Homocigoto , Humanos , Lípidos/sangre , Obesidad/sangre , Obesidad/fisiopatología , Valores de Referencia , Análisis de Regresión , Factores de Riesgo , Eliminación de Secuencia , Tomografía Computarizada por Rayos X
12.
J Clin Endocrinol Metab ; 81(12): 4433-8, 1996 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8954055

RESUMEN

The acute effects of hyperglycemia and hyperinsulinemia on plasma leptin levels were determined in 42 highly trained women athletes (18-69 yr) and 14 sedentary control women (18-50 yr, body mass index < 25 kg/m2), using the glucose clamp technique. The relationships of body composition, physical fitness, age, and plasma leptin levels were examined in all participants. In addition, the effect of weight loss and aerobic exercise and plasma leptin levels were examined in 4 Newly diagnosed untreated noninsulin-dependent diabetes mellitus patients. The time course of plasma leptin levels changed little from basal during hyperglycemic (approximately 10 mmol/L) or hyperinsulinemic-euglycemic (400-3000 pmol/L) clamp studies in either athletes, controls, or noninsulin-dependent diabetes mellitus patients. A strong correlation between plasma leptin levels and fasting insulin was present (r = 0.60, P < 0.001). Plasma leptin and percent fat were higher in controls than athletes (12.6 vs. 4.0 ng/mL and 33.2 vs. 20.8%; both P < 0.001). The relationships between percent fat (dual-energy x-ray absorptiometry) or intraabdominal adipose tissue (computed tomography) and leptin for the entire group were highly significant (r = 0.70, r = 0.52; P < 0.001). When percent fat was controlled, the relationship between fasting insulin and leptin remained (P < 0.002). There was not a significant association between age and plasma leptin levels in a univariate analysis in this population. However, after adjustment for percent fat, a significant inverse relationship between age and leptin appeared (P < 0.05). The weight loss and aerobic exercise program resulted in an average 6 +/- 0.8 kg wt loss. Leptin levels decreased > 28% in each patient (P < 0.01). In conclusion, neither acute hyperglycemia or hyperinsulinemia affects plasma leptin levels. Percent fat is the strongest predictor of leptin levels, even in lean, highly trained women athletes.


Asunto(s)
Tejido Adiposo/anatomía & histología , Hiperglucemia/sangre , Hiperinsulinismo/sangre , Proteínas/análisis , Adolescente , Adulto , Factores de Edad , Anciano , Diabetes Mellitus Tipo 2/sangre , Ejercicio Físico , Femenino , Glucagón/farmacología , Péptido 1 Similar al Glucagón , Humanos , Leptina , Persona de Mediana Edad , Fragmentos de Péptidos/farmacología , Precursores de Proteínas/farmacología , Pérdida de Peso
13.
J Clin Endocrinol Metab ; 82(12): 4088-93, 1997 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9398719

RESUMEN

Insulin is secreted in a pulsatile fashion. Rapid pulses are considered to be important for inhibiting hepatic glucose output, and ultradian pulses for stimulating peripheral glucose disposal. Aging is characterized by a progressive impairment in carbohydrate tolerance. We undertook the current studies to determine whether alterations in pulsatile insulin release accompany the age-related changes in carbohydrate metabolism. Healthy young (n = 8; body mass index, 21 +/- 1 kg/m2; age, 24 +/- 1 yr) and old (n = 9; body mass index, 24 +/- 1 kg/m2; age, 77 +/- 2 yr) volunteers underwent two studies. In the first study, insulin was sampled every 1 min for 150 min, and pulse analysis was conducted using a recently validated multiparameter deconvolution technique. In the second study, insulin was sampled every 10 min for 600 min, and insulin release was evaluated by Cluster analysis. In the 150-min studies, insulin secretory burst mass (P < 0.05) and amplitude (P < 0.01) were reduced in the elderly. In addition, approximate entropy, a measure of irregularity or disorderliness of insulin release, was increased in the aged (P < 0.01). In the 600-min studies, interpulse interval was greater in the aged (P < 0.05), and burst number was less (P < 0.05). We conclude that normal aging is characterized by more disorderly insulin release, a reduction in the amplitude and mass of rapid insulin pulses, and a decreased frequency of ultradian pulses. Whether these alterations in insulin pulsatility contribute directly to the age-related changes in carbohydrate metabolism will require further study.


Asunto(s)
Ciclos de Actividad/fisiología , Envejecimiento/metabolismo , Insulina/metabolismo , Adulto , Anciano , Glucemia/análisis , Composición Corporal , Constitución Corporal , Análisis por Conglomerados , Femenino , Técnica de Clampeo de la Glucosa , Humanos , Insulina/sangre , Secreción de Insulina , Masculino , Concentración Osmolar
14.
J Clin Endocrinol Metab ; 83(8): 2925-32, 1998 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-9709971

RESUMEN

Normal aging is characterized by a progressive impairment in glucose tolerance. An important mechanism underlying the glucose intolerance of aging is an impairment in glucose-induced insulin release. These studies were conducted to determine whether the age-related impairment in insulin release was caused by a decreased beta-cell sensitivity to glucose-dependent insulinotropic polypeptide (GIP). Thirty-one Caucasian men were divided into four groups: two young groups (age range: 19-26 yr, n = 15) and two old groups (age range: 67-79 yr, n = 16). Each volunteer participated in three studies (n = 93 clamps). Hyperglycemic clamps were conducted at two doses [basal plasma glucose (G) + 5.4 mmol/L and G + 12.8 mmol/L] for 120 min. In the initial hyperglycemic clamp, only glucose was infused. In subsequent studies, GIP was infused at a final rate of 2 or 4 pmol/ kg(-1) x min(-1) from 60-120 min. Basal plasma insulin and GIP levels were similar in the young (41 +/- 6 and 51 +/- 6 pmol/L) and the old subjects (42 +/- 6 and 66 +/- 12 pmol/L) in all studies. First- and second-phase insulin responses were similar during the control study and during the first 60 min of each GIP infusion study in both groups. The 90-120 min GIP values were similar between groups and between hyperglycemic plateaus during the 2 and 4 pmol/kg(-1) x min(-1) GIP infusion (young: 342 +/- 28 and 601 +/- 44 pmol/L, old: 387 +/- 45 and 568 +/- 49 pmol/L). In response to the GIP infusions, significant increases in insulin occurred in young and old at both glucose levels (P < 0.01). The potentiation of the insulin response caused by GIP was greater in the young subjects than in the old, in the G + 5.4 mmol/L studies (P < 0.05). However, the insulin response to GIP was similar in both young and old during the G + 12.8 mmol/L clamps. The insulinotropic effect of the incretin was higher in the young and in the old, in the G + 12.8 mmol clamps, than in the G + 5.4 mmol/L clamps. We conclude that normal aging is characterized by a decreased beta-cell sensitivity to GIP during modest hyperglycemia, which may explain, in part, the age-related impairment in glucose-induced insulin release. We also find that the insulinotropic effect of GIP is increased with increasing levels of hyperglycemia.


Asunto(s)
Envejecimiento/fisiología , Glucemia/metabolismo , Polipéptido Inhibidor Gástrico/farmacología , Insulina/metabolismo , Islotes Pancreáticos/efectos de los fármacos , Adulto , Anciano , Polipéptido Inhibidor Gástrico/administración & dosificación , Polipéptido Inhibidor Gástrico/sangre , Glucagón/sangre , Técnica de Clampeo de la Glucosa , Humanos , Insulina/sangre , Secreción de Insulina , Islotes Pancreáticos/metabolismo , Cinética , Masculino , Tasa de Depuración Metabólica
15.
J Clin Endocrinol Metab ; 83(7): 2399-404, 1998 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9661618

RESUMEN

Glucagon-like peptide-1 (GLP-1) is an intestinal insulinotropic hormone that augments insulin secretion in response to meals and lowers blood glucose levels in both type 1 and type 2 diabetic subjects. It has been proposed that a substantial component of the glucose-lowering effects of GLP-1 occurs via insulin-independent mechanisms. However, the interpretations of the studies have been controversial. This study was conducted to examine whether glucagon-like peptide (GLP-1) has an insulin-like effect during euglycemia. Nine young lean men (age, 25 +/- 1.4 yr; body mass index, 24.0 +/- 0.7 kg/m2) volunteered to participate in two euglycemic clamp studies (n = 18 clamps) for 120 min. The initial clamp was performed with a primed continuous infusion of GLP-1 at a final rate of 1.5 pmol/kg.min from 0-60 min. At 60 min, the GLP-1 infusion was terminated, and euglycemia was maintained from 60-120 min. After the GLP-1 study, each individual's plasma insulin level was measured. A second study was performed that was identical to the first, with the infusion of regular insulin in place of GLP-1. Insulin infusion rates were designed in each individual to simulate plasma insulin levels produced during the GLP-1 infusion. The rate of disappearance of glucose was calculated for each subject. Basal plasma insulin levels were similar between studies and averaged 49 +/- 5 pmol/L. Basal GLP-1 levels were also similar (6.0 +/- 1.0 pmol/L). In response to the GLP-1 infusion, although basal plasma glucose levels were clamped, significant increases in insulin occurred in all subjects (P < 0.001). With the nearly identical plasma insulin levels during the two studies (30-60 min levels: GLP-1 study, 151 +/- 48; insulin study, 146 +/- 31 pmol/L), the rate of disappearance of glucose progressively increased in response to both GLP-1 and insulin infusions, but was not significantly different between the studies. The design of the study necessitated conducting the GLP-1 study first, which may have been accompanied by a greater stress than the second study. We, therefore, measured cortisol levels. Basal cortisol (and ACTH) levels were not different. However, cortisol levels significantly increased during the GLP-1 infusions, and this was preceded by an increase in ACTH levels. Somatostatin levels were not different either basally or during the clamps. We conclude that in the euglycemic state, an acute infusion of GLP-1 does not have insulin-like effects in lean nondiabetic men. Intravenous administration of GLP-1 activates hypothalamic neuroendocrine neurons.


Asunto(s)
Glucemia/metabolismo , Glucagón , Hipoglucemiantes/uso terapéutico , Insulina/uso terapéutico , Péptidos/uso terapéutico , Hormona Adrenocorticotrópica/metabolismo , Adulto , Péptido 1 Similar al Glucagón , Péptidos Similares al Glucagón , Técnica de Clampeo de la Glucosa , Humanos , Hidrocortisona/metabolismo , Insulina/metabolismo , Secreción de Insulina , Masculino , Fragmentos de Péptidos , Valores de Referencia , Tasa de Secreción/efectos de los fármacos , Somatostatina/metabolismo
16.
J Clin Endocrinol Metab ; 86(1): 97-103, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11231984

RESUMEN

Increased total and intraabdominal fat (IAF) obesity as well as other metabolic conditions associated with the insulin resistance syndrome (IRS) are related to low levels of sex hormone-binding globulin (SHBG) in young and older Caucasian (CAU) and young African-American (AA) women. We examined whether postmenopausal AA women, a population with a high incidence of obesity and IRS despite low IAF, would have higher levels of circulating SHBG compared with CAU women, and whether there would be negative relationships between indexes of obesity and risk factors associated with IRS and SHBG levels. We measured body composition, SHBG, free testosterone, leptin, glucose tolerance, insulin, and lipoprotein lipids in 55 CAU (mean +/- SD, 59 +/- 7 yr) and 35 AA (57 +/- 6 yr) sedentary women of comparable obesity (48% body fat, by dual energy x-ray absorptiometry). Compared with CAU women, AA women had larger waist (101 vs. 96 cm), larger fat mass (44.9 +/- 8.8 vs. 39.9 +/- 8.1 kg), larger sc fat area (552 +/- 109 vs. 452 +/- 109 cm(2)), and lower IAF/SC ratio (0.28 +/- 0.12 vs. 0.38 +/- 0.15; P < 0.01), but similar waist to hip ratio (0.83). Both groups had similar SHBG (117 vs. 124 nmol/L) and free testosterone (3.7 vs. 3.4 pmol/L) levels, but AA women had a 35% higher leptin, 34% higher fasting insulin, and 39% greater insulin response to a glucose load (P < 0.05) compared with CAU women. In CAU, but not AA, women SHBG correlated negatively with body mass index (r = -0.28; P < 0.05), waist (r = -0.36; P = 0.01), IAF (r = -0.34; P = 0.01), and insulin response to oral glucose (r = -0.37; P < 0.05) and positively with high density lipoprotein cholesterol (r = 0.30; P = 0.03). The relationship between insulin area and SHBG in CAU women disappeared after adjusting for IAF, whereas the relationship between high density lipoprotein cholesterol and SHBG persisted after adjusting for IAF, but not for fat mass. Leptin was positively related to fat mass (P < 0.05) in both groups, but it was related to insulin only in the Caucasian women (P< 0.01). There was a racial difference in the slopes (P< 0.05) of the relationships of leptin to fat mass (P < 0.05). Racial differences in leptin disappeared after adjustment for fasting insulin. These results suggest that the metabolic relationships between total and regional obesity, glucose, and lipid metabolism with SHBG in CAU women are different from those in postmenopausal obese AA women.


Asunto(s)
Población Negra , Obesidad/etnología , Obesidad/patología , Posmenopausia/fisiología , Globulina de Unión a Hormona Sexual/análisis , Población Blanca , Glucemia/análisis , Composición Corporal , Femenino , Hormonas/sangre , Humanos , Lípidos/sangre , Persona de Mediana Edad , Posmenopausia/metabolismo , Testosterona/sangre
17.
J Clin Endocrinol Metab ; 81(10): 3566-72, 1996 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-8855802

RESUMEN

Chronic pancreatitis (CP) is associated with lowered plasma levels and a blunted nutrient-induced release of pancreatic polypeptide (PP). To investigate the possible role of PP on glucose metabolism, we studied male patients with documented CP (n = 5) and obesity-matched control subjects (NL) (n = 6). Hepatic glucose production (HGP) and overall glucose disposal rates were determined by [3-3H]glucose infusion during a hyperinsulinemic-euglycemic clamp during three separate admissions. Basal rates of HGP were higher in CP patients. In response to an infusion of insulin (60 pmol.m-2.min-1), HGP fell 91 +/- 5% in NL subjects but only 68 +/- 8% in CP subjects (P < 0.05). One month later, the clamp was repeated during the final 2 h of an 8-h infusion of bovine PP (2 pmol.kg-1.min-1). HGP before the insulin infusion and its subsequent suppression (NL: 83 +/- 5%; CP: 86 +/- 15%) were nearly identical between groups. In follow-up studies 1 month after the PP infusion, HGP both basally and in response to insulin alone were similar to the first study. During oral glucose tolerance tests (OGTT) performed 18 h after the PP infusion, subjects with normal (n = 7) baseline OGTT responses showed no effect. All patients with diabetic (n = 3) or nondiagnostic (n = 1) OGTT responses, however, demonstrated lowered mean plasma glucose levels (approximately -2.3 mmol/L; range: -0.6 to -7.2 mmol/L). OGTTs repeated 1 month after the PP treatment showed a return to pretreatment responses. We conclude that chronic pancreatitis accompanied by PP deficiency is associated with partial hepatic resistance both in the basal state and in response to hyperinsulinemia. This impairment is reversed after iv PP administration. PP deficiency may therefore play a role in the development of pancreatogenic diabetes caused by pancreatic injury.


Asunto(s)
Glucosa/metabolismo , Polipéptido Pancreático/uso terapéutico , Pancreatitis/tratamiento farmacológico , Pancreatitis/metabolismo , Adulto , Glucemia/metabolismo , Enfermedad Crónica , Glucagón/sangre , Glucosa/biosíntesis , Técnica de Clampeo de la Glucosa , Humanos , Insulina/administración & dosificación , Insulina/sangre , Cinética , Hígado/metabolismo , Masculino , Persona de Mediana Edad , Polipéptido Pancreático/administración & dosificación
18.
Am J Clin Nutr ; 54(3): 516-9, 1991 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-1877508

RESUMEN

The relationship of blood lead concentration to stature was evaluated by examining data from a sample of 1454 Mexican-American children aged 5-12 y, derived from the data sets of the Hispanic Health and Nutrition Examination Survey (HHANES) conducted in 1982-1984. The results indicate that there is an inverse relationship between blood lead concentration in the range 0.14-1.92 mumol/L with stature. The present finding suggests that growth retardation may be associated even with moderate concentrations of blood lead. Therefore, permissible exposure levels of lead for children deserve reexamination in light of the present analysis.


Asunto(s)
Estatura , Hispánicos o Latinos , Plomo/sangre , Factores de Edad , Niño , Preescolar , Femenino , Hematócrito , Humanos , Masculino , Concentración Osmolar , Pobreza
19.
Am J Clin Nutr ; 34(8): 1465-8, 1981 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-6973925

RESUMEN

As shown in 564 girls and 553 boys followed for a period of 18 yr, long-term gain in both subscapular and triceps skinfold thickness was higher in children of lower family income level than those of higher family incomes. This differential fatness gain accounts for the socioeconomic "reversal" of fatness in the female shown in cross-sectional studies and newly extends the phenomenon to both sexes. The finding that low-income children show a greater long-term increase in fatness bears on the prevention and control of obesity.


Asunto(s)
Tejido Adiposo/anatomía & histología , Obesidad/epidemiología , Grosor de los Pliegues Cutáneos , Adolescente , Adulto , Anciano , Niño , Preescolar , Estudios Transversales , Femenino , Estudios de Seguimiento , Encuestas Epidemiológicas , Humanos , Lactante , Masculino , Michigan , Persona de Mediana Edad , Encuestas Nutricionales , Factores Sexuales , Factores Socioeconómicos , Estados Unidos
20.
Am J Clin Nutr ; 34(9): 1645-7, 1981 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-7282587

RESUMEN

As shown in 3321 age-matched pairs of black and white participants in the National Health and Nutrition Examination Surveys (NHANES I) the magnitude of difference in hemoglobin approximates 0.73 g/dl both before and after exclusion of low transferrin saturation values (i.e., equal to or less than 15%). These new income-matched, age-matched comparisons of individuals of the same sex provide a useful estimate of the magnitude of the hemoglobin difference between American blacks and whites.


Asunto(s)
Población Negra , Hemoglobinas/análisis , Población Blanca , Adolescente , Adulto , Factores de Edad , Anciano , Niño , Preescolar , Femenino , Hematócrito , Humanos , Lactante , Masculino , Tamizaje Masivo , Persona de Mediana Edad , Factores Socioeconómicos , Transferrina/análisis , Estados Unidos
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