RESUMEN
A three-dimensional (3D) approach for visualizing the phyletic relationship of living animals is proposed and developed as an alternative to current two-dimensional (2D) evolutionary trees. The 3D tree enhances visualization and qualitative analysis since it simultaneously provides topological (tree-structure) and spatial information (based upon genetically measured distances). However, the meaning of the third dimension, particularly its relationship to temporal processes, and further quantitative analyses emerge as open questions. Our method consists of two phases. First, a 3D representation of the genetic relationships of a related group of extant animals is produced using an optimization algorithm developed here. Second, linear connections are added to suggest a visual representation of the differing evolutionary trajectories of the organisms involved on the basis of a 2D tree algorithm. The method is applied to a set of distantly related Caenophidian snakes, and the resulting relationships are analysed. The discussions here are meant to stimulate the generation of 3D trees in the goal of complementing standard 2D views and, perhaps ultimately, improving our classification of evolutionary relationships.
Asunto(s)
Algoritmos , Evolución Biológica , Animales , Modelos Biológicos , Filogenia , Serpientes/genéticaAsunto(s)
Tejido Adiposo/patología , Resistencia a la Insulina/fisiología , Adulto , Población Negra , Presión Sanguínea , Enfermedades Cardiovasculares/etiología , Diabetes Mellitus/etiología , Ayuno/sangre , Femenino , Prueba de Tolerancia a la Glucosa , Hormonas Esteroides Gonadales/sangre , Humanos , Lípidos/sangre , Obesidad/patología , Obesidad/fisiopatología , Factores de Riesgo , Somatotipos/fisiología , Población BlancaRESUMEN
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.
Asunto(s)
Adipocitos/fisiología , Población Negra , Composición Corporal/fisiología , Resistencia a la Insulina/fisiología , Obesidad/fisiopatología , Población Blanca , Abdomen , Adenosina Desaminasa/farmacología , Adipocitos/metabolismo , Adipocitos/patología , Adolescente , Adulto , Transporte Biológico/fisiología , Nalgas , Ácidos Grasos/metabolismo , Femenino , Glucosa/metabolismo , Humanos , Hiperlipidemias/metabolismo , Hiperlipidemias/fisiopatología , Insulina/farmacología , Resistencia a la Insulina/genética , Lipólisis , Persona de Mediana Edad , Obesidad/genética , Obesidad/metabolismo , Fenilisopropiladenosina/farmacologíaRESUMEN
Portions of two mitochondrial genes (12S and 16S ribosomal RNA) were sequenced to determine the phylogenetic relationships among the major clades of snakes. Thirty-six species, representing nearly all extant families, were examined and compared with sequences of a tuatara and three families of lizards. Snakes were found to constitute a monophyletic group (confidence probability [CP] = 96%), with the scolecophidians (blind snakes) as the most basal lineages (CP = 99%). This finding supports the hypothesis that snakes underwent a subterranean period early in their evolution. Caenophidians (advanced snakes), excluding Acrochordus, were found to be monophyletic (CP = 99%). Among the caenophidians, viperids were monophyletic (CP = 98%) and formed the sister group to the elapids plus colubrids (CP = 94%). Within the viperids, two monophyletic groups were identified: true vipers (CP = 98%) and pit vipers plus Azemiops (CP = 99%). The elapids plus Atractaspis formed a monophyletic clade (CP = 99%). Within the paraphyletic Colubridae, the largely Holarctic Colubrinae was found to be a monophyletic assemblage (CP = 98%), and the Xenodontinae was found to be polyphyletic (CP = 91%). Monophyly of the henophidians (primitive snakes) was neither supported nor rejected because of the weak resolution of relationships among those taxa, except for the clustering of Calabaria with a uropeltid, Rhinophis (CP = 94%).
Asunto(s)
ADN Mitocondrial/genética , ADN Ribosómico/genética , ARN Ribosómico/genética , Serpientes/clasificación , Serpientes/genética , Animales , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADNRESUMEN
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)
Asunto(s)
Tejido Adiposo/anatomía & histología , Población Negra , Glucemia/metabolismo , Lípidos/sangre , Obesidad/fisiopatología , Población Blanca , Adulto , Análisis de Varianza , Antropometría , Presión Sanguínea , Composición Corporal , Índice de Masa Corporal , Peso Corporal , Colesterol/sangre , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Deshidroepiandrosterona/análogos & derivados , Deshidroepiandrosterona/sangre , Sulfato de Deshidroepiandrosterona , Femenino , Hormona Folículo Estimulante/sangre , Prueba de Tolerancia a la Glucosa , Humanos , Insulina/sangre , Hormona Luteinizante/sangre , Obesidad/complicaciones , Factores de Riesgo , Globulina de Unión a Hormona Sexual/análisis , Testosterona/sangre , Triglicéridos/sangreRESUMEN
BACKGROUND AND METHODS: Some obese subjects repeatedly fail to lose weight even though they report restricting their caloric intake to less than 1200 kcal per day. We studied two explanations for this apparent resistance to diet--low total energy expenditure and underreporting of caloric intake--in 224 consecutive obese subjects presenting for treatment. Group 1 consisted of nine women and one man with a history of diet resistance in whom we evaluated total energy expenditure and its main thermogenic components and actual energy intake for 14 days by indirect calorimetry and analysis of body composition. Group 2, subgroups of which served as controls in the various evaluations, consisted of 67 women and 13 men with no history of diet resistance. RESULTS: Total energy expenditure and resting metabolic rate in the subjects with diet resistance (group 1) were within 5 percent of the predicted values for body composition, and there was no significant difference between groups 1 and 2 in the thermic effects of food and exercise. Low energy expenditure was thus excluded as a mechanism of self-reported diet resistance. In contrast, the subjects in group 1 underreported their actual food intake by an average (+/- SD) of 47 +/- 16 percent and overreported their physical activity by 51 +/- 75 percent. Although the subjects in group 1 had no distinct psychopathologic characteristics, they perceived a genetic cause for their obesity, used thyroid medication at a high frequency, and described their eating behavior as relatively normal (all P < 0.05 as compared with group 2). CONCLUSIONS: The failure of some obese subjects to lose weight while eating a diet they report as low in calories is due to an energy intake substantially higher than reported and an overestimation of physical activity, not to an abnormality in thermogenesis.
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Ingestión de Energía , Ejercicio Físico , Obesidad/terapia , Calorimetría , Dieta Reductora , Metabolismo Energético , Femenino , Humanos , Masculino , Persona de Mediana Edad , Obesidad/psicología , Pruebas Psicológicas , Revelación de la VerdadRESUMEN
The absorption of inorganic, trivalent chromium (Cr) by the rat small intestine was investigated by quantifying three components of the absorptive process: 1) Cr uptake from a test meal, 2) Cr transport into the circulation and 3) Cr retention by the intestine. An in vitro, in situ double-perfusion technique was used in which the intestinal vasculature, from the superior mesenteric artery to the portal vein, and the intestinal lumen, from the duodenum to the ileum, were perfused simultaneously. The vasculature was perfused with a synthetic "plasma" (vascular perfusate) while the lumen was perfused with a nutrient-rich solution (intestinal perfusate) at concentrations of trivalent Cr of 0.2-20 mumol/l (10-1000 ppb). Dose-response curves, in which Cr transport, retention and uptake were plotted against the luminal Cr concentration, revealed that Cr absorption is a nonsaturable process. Regardless of the Cr concentration of the intestinal perfusate, 5.90 +/- 0.33% (mean +/- SEM) of the test dose was taken up from the meal, 5.52 +/- 0.33% was transported into the vascular perfusate and 0.38 +/- 0.03% was retained by the small intestine. Based on the criterion of saturability, it was concluded that inorganic, trivalent Cr is absorbed by the nonmediated process of passive diffusion in the small intestine of rats fed a Cr-adequate diet (1.44 micrograms Cr/g diet).
Asunto(s)
Cromo/farmacocinética , Intestino Delgado/metabolismo , Absorción , Animales , Transporte Biológico Activo , Difusión , Relación Dosis-Respuesta a Droga , Masculino , Perfusión , Ratas , Ratas EndogámicasRESUMEN
A simplified method for preparing blood serum and plasma for Zeeman electrothermal atomic absorption spectrometry is described and applied to the measurement of chromium in human serum and plasma. This enzymatic degradation with bacterial protease (EC 3.4.21.3) requires little laboratory apparatus, decreases the work and time of sample preparation, and obviates some potential sources of contamination. We used bovine reference serum (USDA No. 7292) to validate Cr concentration. There was less Cr in serum than in plasma, whether sodium heparin or sodium citrate was used as anticoagulant. For six human subjects, Cr in serum averaged 0.15 (SD 0.02) micrograms/L, 0.26 (SD 0.03) micrograms/L in heparinized plasma, and 0.28 (SD 0.02) micrograms/L in citrated plasma. We postulate that the Cr concentration is lower in serum because some of the Cr binds to proteins complexed with the clot in the coagulation process.
Asunto(s)
Cromo/sangre , Adulto , Citratos , Ácido Cítrico , Heparina , Humanos , Estándares de Referencia , Manejo de Especímenes , Espectrofotometría Atómica/métodos , SubtilisinasRESUMEN
A chromium (Cr) balance study was conducted on a metabolic unit for 12 days in two normal males, ages 62 and 66, ingesting a nutritionally adequate, constant diet. Complete urine and stool collections were obtained daily. The diet, stool, and urine were analyzed for chromium by Zeeman atomic absorption spectrometry. On dietary Cr intakes of 36.9 and 36.7 micrograms/day, only a small fraction of the ingested Cr, 0.9 microgram and 0.5 microgram/day, was absorbed. Most of the dietary Cr, 36.0 micrograms and 36.2 micrograms/day, was excreted in the stool. Urinary Cr was constant from day to day with a mean of 0.30 microgram/day +/- 0.03 SD and 0.28 microgram/day +/- 0.05 SD. The Cr balances (apparent net retention) were positive, 0.6 and 0.2 microgram/day, indicating equilibrium. The average apparent net absorption of Cr for the two subjects was 1.8%.
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Cromo/metabolismo , Cromo/administración & dosificación , Cromo/análisis , Dieta , Humanos , Absorción Intestinal , Masculino , Persona de Mediana Edad , Necesidades Nutricionales , Espectrofotometría AtómicaAsunto(s)
Bacteriología/historia , Centers for Disease Control and Prevention, U.S. , Enfermedades Transmisibles/microbiología , Difteria/microbiología , Brotes de Enfermedades/microbiología , Estudios de Evaluación como Asunto , Femenino , Historia del Siglo XIX , Historia del Siglo XX , Hospitales Urbanos , Humanos , Masculino , Neumonía/microbiología , Estados UnidosAsunto(s)
Comunicación , Cooperación Internacional , Ciencia , Europa (Continente) , Humanos , LenguajeRESUMEN
We treated 70 patients with gallstones with chenodeoxycholic acid over 3 1/2 years and analyzed the factors influencing the outcome of therapy. This treatment was unsuccessful in 11 patients with radiopaque gallstones and in seven with nonfunctioning gallbladders, but 64 per cent with radiolucent gallstones treated for six months or more showed partial or complete gallstone dissolution, and of those whose bile became unsaturated with cholesterol, 100 per cent had evidence of dissolution. In patients with partial or complete gallstone dissolution, the mean post-treatment biliary cholesterol saturation index--0.78 +/- 0.04 (S.E.M.)--was significantly less (P less than 0.001), and the dose of chenodeoxycholic acid (14.4 +/- 1.0 mg per kilogram of body weight per day) significantly more (P less than 0.025) than in those whose gallstones did not change (1.15 +/- 0.04 and 10.6 +/- 1.2 respectively). In patients with radiolucent gallstones, the dose of chenodeoxycholic acid should be based on body weight; 14 to 15 mg per kilogram of body weight per day effectively lowers the saturation index and dissolves gallstones.