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1.
Diabet Med ; 33(1): 32-8, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25970741

RESUMO

AIM: To examine concentrations of biomarkers (adiponectin, C-reactive protein, fibrinogen and tissue plasminogen-activator antigen) associated with glucose homeostasis and diabetes risk by history of gestational diabetes (GDM). METHODS: We conducted a secondary analysis of the Diabetes Prevention Program, a randomized trial of lifestyle intervention or metformin for diabetes prevention. At baseline, participants were overweight and had impaired glucose tolerance. Biomarkers at baseline and 1 year after enrolment were compared between parous women with (n = 350) and without histories of GDM (n = 1466). Cox proportional hazard models evaluated whether history of GDM was associated with diabetes risk, after adjustment for baseline biomarker levels as well as for change in biomarker levels, demographic factors and anthropometrics. RESULTS: At baseline, women with histories of GDM had lower adiponectin (7.5 µg/ml vs. 8.7 µg/ml; p < 0.0001) and greater log C-reactive protein (-0.90 mg/l vs. -0.78 mg/l, p = 0.04) levels than women without histories of GDM, but these associations did not persist after adjustment for demographic factors. Fibrinogen and tissue plasminogen-activator antigen were similar between women with and without histories of GDM. Women with and without histories of GDM had a similar pattern of changes in biomarkers within randomization arm. Adjustment for age, race/ethnicity, baseline weight, change in weight, baseline biomarker level and change in biomarker level did not significantly alter the association between history of GDM, and diabetes risk. CONCLUSIONS: Among women with impaired glucose tolerance, biomarkers in women with and without histories of GDM are similar and respond similarly to lifestyle changes and metformin. Adjustment for biomarker levels did not explain the higher risk of diabetes observed in women with histories of GDM.


Assuntos
Adiponectina/sangue , Proteína C-Reativa/análise , Diabetes Mellitus Tipo 2/etiologia , Diabetes Gestacional/fisiopatologia , Intolerância à Glucose/sangue , Sobrepeso/terapia , Ativador de Plasminogênio Tecidual/sangue , Adulto , Biomarcadores/sangue , Índice de Massa Corporal , Estudos de Coortes , Terapia Combinada , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/prevenção & controle , Dieta Redutora , Feminino , Fibrinogênio/análise , Intolerância à Glucose/complicações , Intolerância à Glucose/etiologia , Intolerância à Glucose/terapia , Humanos , Hipoglicemiantes/uso terapêutico , Estilo de Vida , Pessoa de Meia-Idade , Atividade Motora , Sobrepeso/complicações , Gravidez , Risco , Estados Unidos/epidemiologia , Redução de Peso
2.
J Clin Endocrinol Metab ; 100(10): 3778-86, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26200237

RESUMO

CONTEXT: Steroid sex hormones and SHBG may modify metabolism and diabetes risk, with implications for sex-specific diabetes risk and effects of prevention interventions. OBJECTIVE: This study aimed to evaluate the relationships of steroid sex hormones, SHBG and SHBG single-nucleotide polymorphisms (SNPs) with diabetes risk factors and with progression to diabetes in the Diabetes Prevention Program (DPP). DESIGN AND SETTING: This was a secondary analysis of a multicenter randomized clinical trial involving 27 U.S. academic institutions. PARTICIPANTS: The study included 2898 DPP participants: 969 men, 948 premenopausal women not taking exogenous sex hormones, 550 postmenopausal women not taking exogenous sex hormones, and 431 postmenopausal women taking exogenous sex hormones. INTERVENTIONS: Participants were randomized to receive intensive lifestyle intervention, metformin, or placebo. MAIN OUTCOMES: Associations of steroid sex hormones, SHBG, and SHBG SNPs with glycemia and diabetes risk factors, and with incident diabetes over median 3.0 years (maximum, 5.0 y). RESULTS: T and DHT were inversely associated with fasting glucose in men, and estrone sulfate was directly associated with 2-hour post-challenge glucose in men and premenopausal women. SHBG was associated with fasting glucose in premenopausal women not taking exogenous sex hormones, and in postmenopausal women taking exogenous sex hormones, but not in the other groups. Diabetes incidence was directly associated with estrone and estradiol and inversely with T in men; the association with T was lost after adjustment for waist circumference. Sex steroids were not associated with diabetes outcomes in women. SHBG and SHBG SNPs did not predict incident diabetes in the DPP population. CONCLUSIONS: Estrogens and T predicted diabetes risk in men but not in women. SHBG and its polymorphisms did not predict risk in men or women. Diabetes risk is more potently determined by obesity and glycemia than by sex hormones.


Assuntos
Androgênios/sangue , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/epidemiologia , Estrogênios/sangue , Globulina de Ligação a Hormônio Sexual/metabolismo , Adulto , Idoso , Glicemia/análise , Índice de Massa Corporal , Diabetes Mellitus Tipo 2/prevenção & controle , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Fatores de Risco , Globulina de Ligação a Hormônio Sexual/genética , Estados Unidos , Circunferência da Cintura
4.
Diabetes Obes Metab ; 16(4): 326-33, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24118860

RESUMO

AIMS: To determine the association of metabolic syndrome (MetS) and its components with diabetes risk in participants with impaired glucose tolerance (IGT), and whether intervention-related changes in MetS lead to differences in diabetes incidence. METHODS: We used the National Cholesterol Education Program/Adult Treatment Panel III (NCEP/ATP III) revised MetS definition at baseline and intervention-related changes of its components to predict incident diabetes using Cox models in 3234 Diabetes Prevention Program (DPP) participants with IGT over an average follow-up of 3.2 years. RESULTS: In an intention-to-treat analysis, the demographic-adjusted hazard ratios (95% confidence interval) for diabetes in those with MetS (vs. no MetS) at baseline were 1.7 (1.3-2.3), 1.7 (1.2-2.3) and 2.0 (1.3-3.0) for placebo, metformin and lifestyle groups, respectively. Higher levels of fasting plasma glucose and triglycerides at baseline were independently associated with increased risk of diabetes. Greater waist circumference (WC) was associated with higher risk in placebo and lifestyle groups, but not in the metformin group. In a multivariate model, favourable changes in WC (placebo and lifestyle) and high-density lipoprotein cholesterol (placebo and metformin) contributed to reduced diabetes risk. CONCLUSIONS: MetS and some of its components are associated with increased diabetes incidence in persons with IGT in a manner that differed according to DPP intervention. After hyperglycaemia, the most predictive factors for diabetes were baseline hypertriglyceridaemia and both baseline and lifestyle-associated changes in WC. Targeting these cardiometabolic risk factors may help to assess the benefits of interventions that reduce diabetes incidence.


Assuntos
Glicemia/metabolismo , Doenças Cardiovasculares/prevenção & controle , Diabetes Mellitus Tipo 2/prevenção & controle , Angiopatias Diabéticas/prevenção & controle , Intolerância à Glucose/complicações , Intolerância à Glucose/terapia , Hipoglicemiantes/uso terapêutico , Síndrome Metabólica/prevenção & controle , Metformina/uso terapêutico , Comportamento de Redução do Risco , Triglicerídeos/sangue , Fatores Etários , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/etiologia , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/etiologia , Angiopatias Diabéticas/sangue , Angiopatias Diabéticas/epidemiologia , Dieta Redutora , Exercício Físico , Jejum , Feminino , Intolerância à Glucose/tratamento farmacológico , Humanos , Incidência , Masculino , Síndrome Metabólica/sangue , Síndrome Metabólica/epidemiologia , Síndrome Metabólica/etiologia , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Indução de Remissão , Fatores de Risco , Circunferência da Cintura
5.
Diabet Med ; 30(1): 46-55, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22812594

RESUMO

AIMS: Whether long-term cardiovascular risk is reduced by the Diabetes Prevention Program interventions is unknown. The aim of this study was to determine the long-term differences in cardiovascular disease risk factors and the use of lipid and blood pressure medications by the original Diabetes Prevention Program intervention group. METHODS: This long-term follow-up (median 10 years, interquartile range 9.0-10.5) of the three-arm Diabetes Prevention Program randomized controlled clinical trial (metformin, intensive lifestyle and placebo), performed on 2766 (88%) of the Diabetes Prevention Program participants (who originally had impaired glucose tolerance), comprised a mean of 3.2 years of randomized treatment, approximately 1-year transition (during which all participants were offered intensive lifestyle intervention) and 5 years follow-up (Diabetes Prevention Program Outcomes Study). During the study, participants were followed in their original groups with their clinical care being provided by practitioners outside the research setting. The study determined lipoprotein profiles and blood pressure and medication use annually. RESULTS: After 10 years' follow-up from Diabetes Prevention Program baseline, major reductions were seen for systolic (-2 to -3) and diastolic (-6 to -6.5 mmHg) blood pressure, and for LDL cholesterol (-0.51 to -0.6 mmol/l) and triglycerides (-0.23 to -0.25 mmol/l) in all groups, with no between-group differences. HDL cholesterol also rose significantly (0.14 to 0.15 mmol/l) in all groups. Lipid (P = 0.01) and blood pressure (P = 0.09) medication use, however, were lower for the lifestyle group during the Diabetes Prevention Program Outcomes Study. CONCLUSION: Overall, intensive lifestyle intervention achieved, with less medication, a comparable long-term effect on cardiovascular disease risk factors, to that seen in the metformin and placebo groups.


Assuntos
Diabetes Mellitus/prevenção & controle , Angiopatias Diabéticas/etiologia , Análise de Variância , Anti-Hipertensivos/uso terapêutico , Feminino , Seguimentos , Humanos , Hipoglicemiantes/uso terapêutico , Hipolipemiantes/uso terapêutico , Masculino , Metformina/uso terapêutico , Pessoa de Meia-Idade , Fatores de Risco , Comportamento de Redução do Risco
6.
Diabet Med ; 29(12): 1579-88, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22443353

RESUMO

AIMS: Baseline adiponectin concentrations predict incident Type 2 diabetes mellitus in the Diabetes Prevention Program. We tested the hypothesis that common variants in the genes encoding adiponectin (ADIPOQ) and its receptors (ADIPOR1, ADIPOR2) would associate with circulating adiponectin concentrations and/or with diabetes incidence in the Diabetes Prevention Program population. METHODS: Seventy-seven tagging single-nucleotide polymorphisms (SNPs) in ADIPOQ (24), ADIPOR1 (22) and ADIPOR2 (31) were genotyped. Associations of SNPs with baseline adiponectin concentrations were evaluated using linear modelling. Associations of SNPs with diabetes incidence were evaluated using Cox proportional hazards modelling. RESULTS: Thirteen of 24 ADIPOQ SNPs were significantly associated with baseline adiponectin concentrations. Multivariable analysis including these 13 SNPs revealed strong independent contributions of rs17366568, rs1648707, rs17373414 and rs1403696 with adiponectin concentrations. However, no ADIPOQ SNPs were directly associated with diabetes incidence. Two ADIPOR1 SNPs (rs1342387 and rs12733285) were associated with ∼18% increased diabetes incidence for carriers of the minor allele without differences across treatment groups, and without any relationship with adiponectin concentrations. CONCLUSIONS: ADIPOQ SNPs are significantly associated with adiponectin concentrations in the Diabetes Prevention Program cohort. This observation extends prior observations from unselected populations of European descent into a broader multi-ethnic population, and confirms the relevance of these variants in an obese/dysglycaemic population. Despite the robust relationship between adiponectin concentrations and diabetes risk in this cohort, variants in ADIPOQ that relate to adiponectin concentrations do not relate to diabetes risk in this population. ADIPOR1 variants exerted significant effects on diabetes risk distinct from any effect of adiponectin concentrations.


Assuntos
Adiponectina/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Resistência à Insulina , Obesidade/metabolismo , Receptores de Adiponectina/metabolismo , Adiponectina/genética , Alelos , Diabetes Mellitus Tipo 2/genética , Feminino , Variação Genética , Genótipo , Humanos , Incidência , Resistência à Insulina/genética , Masculino , Obesidade/genética , Polimorfismo de Nucleotídeo Único/genética , Modelos de Riscos Proporcionais , Receptores de Adiponectina/genética
7.
Diabetologia ; 54(10): 2570-4, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21779873

RESUMO

AIMS/HYPOTHESIS: Individuals with impaired glucose tolerance have increased proinsulin levels, despite normal glucose or C-peptide levels. In the Diabetes Prevention Program (DPP), increased proinsulin levels predicted type 2 diabetes and proinsulin levels were significantly reduced following treatment with metformin, lifestyle modification or troglitazone compared with placebo. Genetic and physiological studies suggest a role for the zinc transporter gene SLC30A8 in diabetes risk, possibly through effects on insulin-processing in beta cells. We hypothesised that the risk allele at the type 2 diabetes-associated missense polymorphism rs13266634 (R325W) in SLC30A8 would predict proinsulin levels in individuals at risk of type 2 diabetes and may modulate response to preventive interventions. METHODS: We genotyped rs13266634 in 3,007 DPP participants and examined its association with fasting proinsulin and fasting insulin at baseline and at 1 year post-intervention. RESULTS: We found that increasing dosage of the C risk allele at SLC30A8 rs13266634 was significantly associated with higher proinsulin levels at baseline (p = 0.002) after adjustment for baseline insulin. This supports the hypothesis that risk alleles at SLC30A8 mark individuals with insulin-processing defects. At the 1 year analysis, proinsulin levels decreased significantly in all groups receiving active intervention and were no longer associated with SLC30A8 genotype (p = 0.86) after adjustment for insulin at baseline and 1 year. We found no genotype × treatment interactions at 1 year. CONCLUSIONS/INTERPRETATION: In prediabetic individuals, genotype at SLC30A8 predicts baseline proinsulin levels independently of insulin levels, but does not predict proinsulin levels after amelioration of insulin sensitivity at 1 year.


Assuntos
Proteínas de Transporte de Cátions/genética , Cromanos/uso terapêutico , Diabetes Mellitus/sangue , Diabetes Mellitus/genética , Metformina/uso terapêutico , Polimorfismo Genético/genética , Proinsulina/sangue , Tiazolidinedionas/uso terapêutico , Adulto , Peptídeo C/sangue , Diabetes Mellitus/tratamento farmacológico , Diabetes Mellitus/terapia , Diabetes Mellitus Tipo 2/genética , Feminino , Humanos , Insulina/sangue , Masculino , Pessoa de Meia-Idade , Troglitazona , Transportador 8 de Zinco
8.
Diabet Med ; 28(9): 1088-95, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21517955

RESUMO

AIM: To determine if a regimen with prandial + basal insulin compared with basal insulin attenuates post-meal inflammatory and glycative biomarkers in patients with Type 2 diabetes. METHODS: This test-meal sub-study in the USA is from a previously reported clinical trial comparing the effect on glycaemic control of 24 weeks of thrice-daily pre-meal insulin lispro mix 50 (50% insulin lispro, 50% insulin lispro protamine suspension) or bedtime insulin glargine, both plus metformin. In the sub-study, glucose, insulin, triglycerides, high-sensitivity C-reactive protein, tumour necrosis factor α, interleukin-6, methylglyoxal and 3-deoxyglucosone were measured during the post-meal period of a mixed-meal breakfast at the final visit. Prandial + basal (n = 25) and basal (n = 21) insulin were administered at the same times as during the previous 24 weeks. RESULTS: Post-meal, the prandial + basal insulin group had significantly higher insulin, lower glucose and triglycerides, as well as lower high-sensitivity C-reactive protein, tumour necrosis factor α and interleukin-6, than the basal insulin group. Glucose incremental area under the concentration curve significantly correlated with high-sensitivity C-reactive protein, tumour necrosis factor α, interleukin-6, methylglyoxal and 3-deoxyglucosone incremental area under the concentration curve. Insulin incremental area under the concentration curve correlated inversely with high-sensitivity C-reactive protein and tumour necrosis factor α incremental area under the concentration curve. However, after adjusting for glucose incremental area under the concentration curve, these inverse correlations were no longer significant. Triglyceride incremental area under the concentration curve was not correlated with any biomarker incremental area under the concentration curve. CONCLUSIONS: Controlling post-meal hyperglycaemia with prandial + basal insulin in patients with Type 2 diabetes attenuates meal-induced increases in high-sensitivity C-reactive protein, interleukin-6 and tumour necrosis factor α compared with basal insulin. The rise in post-meal glucose, but not triglycerides, significantly correlated with the rise in post-meal inflammatory and glycative biomarkers.


Assuntos
Proteína C-Reativa/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Hiperglicemia/metabolismo , Hipoglicemiantes/farmacologia , Insulina/análogos & derivados , Interleucina-6/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Adulto , Idoso , Diabetes Mellitus Tipo 2/tratamento farmacológico , Feminino , Hemoglobinas Glicadas , Humanos , Hiperglicemia/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Insulina/farmacologia , Insulina/uso terapêutico , Insulina de Ação Prolongada , Masculino , Pessoa de Meia-Idade , Período Pós-Prandial , Resultado do Tratamento , Estados Unidos
9.
Diabetes Obes Metab ; 11(9): 855-64, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19508464

RESUMO

AIM: To evaluate the effects of the usual starting and next higher doses of ezetimibe/simvastatin and atorvastatin on the cholesterol content of lipoprotein subclasses in patients with type 2 diabetes and hypercholesterolaemia. METHODS: This post hoc analysis compared the effects of treatment with ezetimibe/simvastatin 10/20 mg vs. atorvastatin 10 and 20 mg/day and ezetimibe/simvastatin 10/40 mg/day vs. atorvastatin 40 mg/day on the cholesterol content of lipoprotein subclasses in the modified intent-to-treat (mITT) population (n = 1013) and in subgroups of patients with triglyceride (TG) levels <200 mg/dl (n = 600) and >or=200 mg/dl (2.6 mmol/l) (n = 413). RESULTS: Ezetimibe/simvastatin significantly reduced low-density lipoprotein cholesterol (LDL-C) subclasses LDL(1)-C, LDL(2)-C and LDL(3)-C; real LDL-C (LDL-C(r)); intermediate-density lipoprotein cholesterol (IDL-C), IDL(1)-C, IDL(2)-C; very low-density lipoprotein cholesterol (VLDL-C), VLDL(3)-C; and remnant-like lipoprotein cholesterol (RLP-C) from baseline more than atorvastatin at all dose comparisons (p < 0.01) in the mITT population. Significant improvements were also observed in high-density lipoprotein cholesterol (HDL-C) subclass HDL(3)-C at the ezetimibe/simvastatin 10/20 mg vs. atorvastatin 20 mg and highest dose comparisons (p < 0.001) and in VLDL(1 + 2)-C at the lowest and highest dose comparisons (p < 0.001). Changes in LDL(4)-C and LDL-C subclass patterns (A, B and I) were comparable for both treatments. Generally, similar results were observed for patients with TG levels <200 and >or=200 mg/dl (2.3 mmol). For both treatments, notable differences between TG subgroups were that patients with elevated TGs had smaller reductions in LDL(2)-C, slightly smaller decreases in all IDL subclasses and greater decreases in all VLDL-C subclasses than those with lower TG levels. Frequency of pattern B was also reduced more in patients with higher TGs for both treatments. CONCLUSIONS: Ezetimibe/simvastatin reduced the cholesterol content of most lipoprotein subclasses from baseline with generally similar efficacy in patients with low and high TGs. Despite the different mechanism of action of ezetimibe, the response to ezetimibe/simvastatin and atorvastatin treatment related to these lipoprotein subclasses was generally consistent with the overall effects of these therapies on the major lipid/lipoprotein classes. The clinical significance of these results awaits further study.


Assuntos
Anticolesterolemiantes/administração & dosagem , Azetidinas/administração & dosagem , Diabetes Mellitus Tipo 2/tratamento farmacológico , Ácidos Heptanoicos/administração & dosagem , Hipercolesterolemia/tratamento farmacológico , Pirróis/administração & dosagem , Sinvastatina/administração & dosagem , Adulto , Idoso , Atorvastatina , Colesterol/sangue , Colesterol/classificação , HDL-Colesterol/sangue , LDL-Colesterol/sangue , VLDL-Colesterol/sangue , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Quimioterapia Combinada , Ezetimiba , Feminino , Humanos , Hipercolesterolemia/sangue , Hipercolesterolemia/complicações , Masculino , Pessoa de Meia-Idade , Adulto Jovem
10.
Int J Obes Relat Metab Disord ; 27(1): 82-7, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12532158

RESUMO

OBJECTIVE: To compare plasma plasminogen activator inhibitor type 1 (PAI-1) levels and to examine the association of PAI-1 with visceral adiposity and other components of the metabolic syndrome in overweight and obese premenopausal African-American (AA) and Caucasian (CC) women. DESIGN: Cross-sectional study. SUBJECTS: 33 CC and 23 AA healthy, overweight and obese, premenopausal women (age 19-53 y, body mass index 28.1-48.9 kg/m(2)). MEASUREMENTS: Body mass index, sagittal diameter, waist circumference, percentage body fat, visceral and subcutaneous adipose tissue (by anthropometry, magnetic resonance imaging (MRI), and bioelectric impedance techniques), PAI-1, leptin, lipids, glucose, insulin, and insulin resistance (by HOMA IR). RESULTS: AA women had lower triglyceride levels and less visceral adipose tissue (VAT) volume than CC despite similar BMI. PAI-1 levels were not significantly different in the two groups. Insulin resistance was associated with PAI-1 in both groups but only in CC women were VAT, triglyceride, HDL cholesterol and blood pressure related to plasma PAI-1 levels. Multiple regression analysis showed that VAT in CC and insulin resistance in AA were independent predictors of PAI-1. CONCLUSION: VAT is significantly associated with circulating PAI-1 levels in overweight and obese CC but not AA premenopausal women.


Assuntos
Negro ou Afro-Americano , Resistência à Insulina/fisiologia , Obesidade/metabolismo , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Tecido Adiposo/metabolismo , Adulto , Peso Corporal , Dieta , Exercício Físico , Feminino , Humanos , Recém-Nascido , Síndrome Metabólica/metabolismo , Pessoa de Meia-Idade , Pré-Menopausa , Vísceras/metabolismo
11.
Plant Cell ; 13(11): 2409-25, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11701878

RESUMO

We investigated gene activity within the giant embryos of the scarlet runner bean (Phaseolus coccineus) to gain understanding of the processes by which the apical and basal cells become specified to follow different developmental pathways after division of the zygote. We identified two mRNAs, designated G564 and C541, that accumulate specifically within the suspensor of globular-stage embryos. G564 mRNA accumulates uniformly throughout the suspensor, whereas C541 mRNA accumulates to a higher level within the large basal cells of the suspensor that anchor the embryo to the surrounding seed tissue. Both G564 and C541 mRNAs begin to accumulate shortly after fertilization and are present within the two basal cells of embryos at the four-cell stage. In contrast, at the same stage, these mRNAs are not detectable within the two descendants of the apical cell. Nor are they detectable within cells of the embryo sac before fertilization, including the egg cell. We used a G564/beta-glucuronidase reporter gene to show that the G564 promoter is activated specifically within the basal region and suspensor of preglobular tobacco embryos. Analysis of the G564 promoter identified a sequence domain required for transcription within the suspensor that contains several copies of a conserved motif. These results show that derivatives of the apical and basal cells transcribe different genes as early as the four-cell stage of embryo development and suggest that the apical and basal cells are specified at the molecular level after division of the zygote.


Assuntos
Regulação da Expressão Gênica de Plantas , Phaseolus/crescimento & desenvolvimento , RNA Mensageiro/genética , RNA de Plantas/genética , Sementes/fisiologia , Sequência de Bases , Biblioteca Gênica , Genes Reporter , Hibridização In Situ , Dados de Sequência Molecular , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , RNA de Plantas/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência , Homologia de Sequência do Ácido Nucleico , Nicotiana/genética , Transcrição Gênica , Transformação Genética
12.
Proc Natl Acad Sci U S A ; 98(24): 14156-61, 2001 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-11698668

RESUMO

All plants flower late in their life cycle. For example, in Arabidopsis, the shoot undergoes a transition and produces reproductive flowers after the adult phase of vegetative growth. Much is known about genetic and environmental processes that control flowering time in mature plants. However, little is understood about the mechanisms that prevent plants from flowering much earlier during embryo and seedling development. Arabidopsis embryonic flower (emf1 and emf2) mutants flower soon after germination, suggesting that a floral repression mechanism is established in wild-type plants that prevents flowering until maturity. Here, we show that polycomb group proteins play a central role in repressing flowering early in the plant life cycle. We found that mutations in the Fertilization Independent Endosperm (FIE) polycomb gene caused the seedling shoot to produce flower-like structures and organs. Flower-like structures were also generated from the hypocotyl and root, organs not associated with reproduction. Expression of floral induction and homeotic genes was derepressed in mutant embryos and seedlings. These results suggest that FIE-mediated polycomb complexes are an essential component of a floral repression mechanism established early during plant development.


Assuntos
Proteínas de Arabidopsis , Arabidopsis/crescimento & desenvolvimento , Proteínas de Plantas/fisiologia , Proteínas Repressoras/fisiologia , Arabidopsis/embriologia , Arabidopsis/genética , Fusão Gênica Artificial , Caulimovirus/genética , Expressão Gênica , Genes de Plantas , Vetores Genéticos , Proteínas de Fluorescência Verde , Proteínas Luminescentes/genética , Proteínas de Plantas/genética , Proteínas do Grupo Polycomb , Regiões Promotoras Genéticas , Proteínas Repressoras/genética , Sementes , Fatores de Tempo , Transgenes
13.
J Spinal Cord Med ; 24(1): 2-9, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11587430

RESUMO

BACKGROUND: People with chronic paraplegia frequently experience dyslipidemias characterized by depressed levels of high-density lipoprotein cholesterol (HDL-C) and elevated levels of low-density lipoprotein cholesterol (LDL-C). These abnormal lipid profiles and poor fitness levels increase their risk for cardiovascular disease. METHODS: To test the hypothesis that circuit resistance exercise training improves both upper-extremity fitness and the atherogenic lipid profile in persons with chronic paraplegia, a homogeneous cohort of 5 men with neurologically complete spinal cord injuries at T6 to L1 underwent 3 months of exercise training using uninterrupted resistance and endurance exercises of the upper extremities. Training was performed 3 times a week on alternating days. RESULTS: Results of graded arm exercise testing showed a 30.3% improvement in peak oxygen consumption (P < .01), a 33.5% increase in time to fatigue (P < .01) and a 30.4% increase in peak power output (P < .05). Pretraining total cholesterol levels (TC) were in the low-risk category and were nonsignificantly lowered following training. Similar nonsignificant reductions of plasma triglycerides averaging 12 mg/dL were attained. Conversely, a 25.9% lowering of LDL-C (P < .05) and 9.8% elevation of HDL-C (P < .05) were observed after training. These changes reduced the average LDL-C-to-HDL-C ratio by 1 unit (P < .05) and the TC-to-HDL-C ratio from 5.0 +/- 1.1 (mean +/- SD) to 3.9 +/- 0.7 (P < .05). CONCLUSIONS: This change reflects a cardiovascular risk reduction of almost 25%; the TC/HDL-C declined from the high-risk score of 5.0 to near the desired score of 3.5. These findings support the beneficial effects of circuit exercise resistance training on fitness and atherogenic lipid profiles in persons with chronic paraplegia.


Assuntos
Doenças Cardiovasculares/prevenção & controle , Hiperlipidemias/prevenção & controle , Lipídeos/sangue , Paraplegia/terapia , Aptidão Física/fisiologia , Traumatismos da Medula Espinal/fisiopatologia , Adulto , Humanos , Hiperlipidemias/sangue , Lipoproteínas/sangue , Masculino , Paraplegia/sangue , Traumatismos da Medula Espinal/sangue
14.
Proc Natl Acad Sci U S A ; 98(20): 11806-11, 2001 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-11573014

RESUMO

The Arabidopsis LEAFY COTYLEDON2 (LEC2) gene is a central embryonic regulator that serves critical roles both early and late during embryo development. LEC2 is required for the maintenance of suspensor morphology, specification of cotyledon identity, progression through the maturation phase, and suppression of premature germination. We cloned the LEC2 gene on the basis of its chromosomal position and showed that the predicted polypeptide contains a B3 domain, a DNA-binding motif unique to plants that is characteristic of several transcription factors. We showed that LEC2 RNA accumulates primarily during seed development, consistent with our finding that LEC2 shares greatest similarity with the B3 domain transcription factors that act primarily in developing seeds, VIVIPAROUS1/ABA INSENSITIVE3 and FUSCA3. Ectopic, postembryonic expression of LEC2 in transgenic plants induces the formation of somatic embryos and other organ-like structures and often confers embryonic characteristics to seedlings. Together, these results suggest that LEC2 is a transcriptional regulator that establishes a cellular environment sufficient to initiate embryo development.


Assuntos
Proteínas de Arabidopsis , Arabidopsis/genética , Proteínas Estimuladoras de Ligação a CCAAT , Proteínas Estimuladoras de Ligação a CCAAT/genética , Proteínas de Ligação ao GTP , Proteínas de Plantas/genética , Proteínas , Proteínas Repressoras , Proteínas de Saccharomyces cerevisiae , Fatores de Transcrição/genética , Sequência de Aminoácidos , Arabidopsis/crescimento & desenvolvimento , Proteínas Estimuladoras de Ligação a CCAAT/química , Complexo do Signalossomo COP9 , Cotilédone/crescimento & desenvolvimento , Cotilédone/fisiologia , Proteínas Fúngicas/genética , Regulação da Expressão Gênica no Desenvolvimento , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas Quinases Ativadas por Mitógeno/genética , Dados de Sequência Molecular , Folhas de Planta/metabolismo , Proteínas de Plantas/química , Raízes de Plantas/metabolismo , Sementes/fisiologia , Alinhamento de Sequência , Fatores de Transcrição/química
15.
Plant Physiol ; 126(2): 717-30, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11402200

RESUMO

We identified a T-DNA-generated mutation in the chaperonin-60alpha gene of Arabidopsis that produces a defect in embryo development. The mutation, termed schlepperless (slp), causes retardation of embryo development before the heart stage, even though embryo morphology remains normal. Beyond the heart stage, the slp mutation results in defective embryos with highly reduced cotyledons. slp embryos exhibit a normal apical-basal pattern and radial tissue organization, but they are morphologically retarded. Even though slp embryos are competent to transcribe two late-maturation gene markers, this competence is acquired more slowly as compared with wild-type embryos. slp embryos also exhibit a defect in plastid development-they remain white during maturation in planta and in culture. Hence, the overall developmental phenotype of the slp mutant reflects a lesion in the chloroplast that affects embryo development. The slp phenotype highlights the importance of the chaperonin-60alpha protein for chloroplast development and subsequently for the proper development of the plant embryo and seedling.


Assuntos
Arabidopsis/embriologia , Chaperonina 60/genética , Mutação , Sementes/crescimento & desenvolvimento , Sequência de Aminoácidos , Arabidopsis/genética , Chaperonina 60/química , DNA Bacteriano , DNA Complementar , Teste de Complementação Genética , Germinação , Dados de Sequência Molecular , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Homologia de Sequência de Aminoácidos , Transformação Genética
16.
Clin Lab Med ; 21(1): 147-72, vii, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11321932

RESUMO

Atherosclerotic cardiovascular disease is the most important cause of morbidity and mortality in diabetic subjects. Abnormalities in circulating lipids and lipoproteins are considered to be important risk factors for cardiovascular disease because they occur with increased frequency in diabetic individuals. Because reversal of these abnormalities carries the potential for preventing or ameliorating cardiovascular disease, their identification and management with other cardiovascular disease risk factors deserve equal importance to the management of hyperglycemia and frequently are complementary to it.


Assuntos
Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 2/complicações , Hipertrigliceridemia/complicações , Hipertrigliceridemia/metabolismo , Doença da Artéria Coronariana/etiologia , Doença da Artéria Coronariana/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Hipertrigliceridemia/tratamento farmacológico , Hipolipemiantes/uso terapêutico
17.
Horm Metab Res ; 33(1): 39-43, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11280714

RESUMO

Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis in central obesity has been demonstrated in women. We studied the corticotropin (ACTH) and cortisol response to ovine corticotropin releasing hormone (oCRH) and its association to parameters of adiposity and insulin resistance in a group of 19 healthy obese (BMI > 25 kg/m2) and 9 non-obese men. Relative insulin resistance was assessed by the homeostatic model assessment (HOMA IR). Baseline ACTH was similar, while cortisol was lower in the obese group. The ACTH response to oCRH was significantly higher in the obese group. ACTH incremental area under the curve (iAUC) correlated with age, HOMA IR, and sagittal diameter but not with leptin. In multiple regression analysis, only HOMA IR was an independent predictor of ACTH iAUC. In conclusion, obese men have hyperactivity of the HPA axis at the pituitary level, which appears to be linked to insulin resistance.


Assuntos
Hormônio Liberador da Corticotropina/farmacologia , Resistência à Insulina/fisiologia , Obesidade Mórbida/sangue , Hipófise/efeitos dos fármacos , Hormônio Adrenocorticotrópico/sangue , Adulto , Animais , Peso Corporal , Teste de Tolerância a Glucose , Humanos , Hidrocortisona/sangue , Masculino , Pessoa de Meia-Idade , Ovinos
19.
J Appl Physiol (1985) ; 89(2): 636-43, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10926648

RESUMO

This study sought to determine whether visceral adipose tissue (VAT) and/or its anthropometric surrogates could significantly predict health-related variables (HRV) in overweight Caucasian (CC) (n = 36) and African-American (AA) (n = 30) women. With the use of magnetic resonance imaging, findings showed significantly higher volume and area of VAT (P < 0.0001 for both) as well as higher triacylglycerol (P = 0.009) in CC compared with AA women. Furthermore, VAT volume, race, and VAT volume x race interaction could significantly predict triacylglycerol (P = 0.0094), high-density lipoprotein cholesterol (P = 0.0057), insulin (P = 0.0002), and insulin resistance (P < 0. 0001). Additionally, the VAT volume x race interaction for insulin (P = 0.040) and insulin resistance (P = 0.003) was significant. In a separate analysis, waist circumference and race predicted the identical variables. Our results support the use of volume or area of VAT in predicting HRV in CC women; however, its use in AA women appears limited. In contrast, waist circumference can provide a suitable VAT alternative for both CC and AA women; however, VAT clearly represents the more powerful predictor.


Assuntos
Tecido Adiposo/fisiologia , Antropometria , Indicadores Básicos de Saúde , Grupos Raciais , Adulto , Apolipoproteínas B/sangue , População Negra , Pressão Sanguínea/fisiologia , Composição Corporal/fisiologia , Peso Corporal/fisiologia , Dieta , Exercício Físico/fisiologia , Feminino , Humanos , Lipoproteínas/sangue , Lipoproteínas LDL/metabolismo , Imageamento por Ressonância Magnética , Obesidade/fisiopatologia , Estresse Psicológico/fisiopatologia , Resistência Vascular/fisiologia , População Branca
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