ISSN:1068-3097    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Although this represents a relatively recent notion, the implication of peroxisome proliferator-activated receptors (PPARs) in human diseases is undergoing an exceptionally increasing rate of scientific study, currently involving most specialties of medicine. The present review starts with a survey of 1) the molecular regulatory properties of PPARs, including their interactions with cell transcription, cell signaling pathways, and natural and synthetic ligands; and 2) the biologically functional properties of PPARs, which addresses reversal of universal pathogenesis pathways (eg, inflammation, cell dedifferentiation, vascular tree development), explaining why in most cases the PPAR dependence of human disorders refers to their PPAR-induced therapeutic improvement rather than to their induction by PPAR-altered expression. Recent advances in the specific involvement of PPARs in human disorders covers the following items: 1) insulin resistance (diabetes) and obesity states with their complications (hypertension, dyslipidemia, atheromatosis); 2) cardiovascular disorders with emphasis on atherosclerosis; 3) neoplastic proliferative diseases (breast, gastric, prostate, and colon cancers; liposarcoma, choriocarcinoma, acute myeloid leukemia); and 4) inflammatory diseases (including digestive, cutaneous, and rheumatismal inflammatory processes).

ISSN:1068-3097    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Despite over 60 years’ accumulation of data from animal studies indicating that the kidney produces glucose responsive to hormonal and other physiologic and pathologic perturbations, most medical textbooks consider the liver to be the sole source of glucose in humans under most conditions. This view was based on simple (no longer valid) net renal glucose balance calculations. However, recent studies in humans and dogs using more sophisticated techniques (net balance plus isotopic measurements) indicate 1) that the kidney simultaneously produces and uses glucose and that it is a major gluconeogenic organ; 2) that the human kidney contributes significantly to the overall release of glucose into the circulation postabsorptively and under other conditions; and 3) that its release of glucose is under hormonal control and is increased during hypoglycemia and in diabetes.

ISSN:1068-3097    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Based on the observation that some common foods containing the same type and the same amount of carbohydrates were capable of producing different glycemic responses in normal subjects and subjects with diabetes, the concept of the glycemic index was developed. The glycemic index classifies carbohydrate-containing foods according to the patient’s glycemic responses expressed as a percentage of a reference food such as bread. The different glycemic responses to foods containing the same amount of carbohydrates depend mainly, at least in normal subjects, on their different rates of absorption by the small intestine. A major factor affecting absorption by the gut is the type of carbohydrates: mono-or disaccharides versus polysaccharides, the proportion of amylose versus amylopectin composing the polysaccharides, and the presence or absence of soluble dietary fibers. It was hoped that the glycemic index concept would provide a better means of predicting the impact of carbohydrate-containing foods on the glycemic response and help in the dietary prescription for patients with diabetes. Unfortunately, few studies have been published on the use of low glycemic index diet on the glycemic control of type I diabetes. In fact, no long-term studies are available; only acute and short-term studies have been done. Eight acute studies have assessed the effect of low glycemic index versus high glycemic index diets in a total of 80 subjects with type I diabetes. Only one of eight studies showed a significant decrease in the postprandial plasma glucose rise with the meal. Only five studies have evaluated the short-term effect of a low glycemic index diet in 42 subjects with type I diabetes. The mean treatment duration was 4 ± 0.7 weeks, and the mean reduction in glycemic index was 25.8% ± 5.5%; only one of the five studies showed a significant decrease in the fructosamine level after the low glycemic index diet. Overall, these studies suggest that the use of low glycemic index carbohydrate-containing foods does not have any advantage in the treatment of type I diabetes over the use of carbohydrate count or food exchanges. However, there is no contraindication to incorporating low glycemic index foods in the dietary treatment of type I diabetes.

ISSN:1068-3097    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Diagnosing diabetes can be easy in patients with symptoms of diabetes and markedly elevated blood glucose levels. However, defining cut-off points for diagnosing diabetes in asymptomatic individuals can be more difficult. Blood glucose levels tend to exist in a continuum in populations, without clear cut-off points separating normal from abnormal. This article reviews the historical background for diagnosing diabetes as well as the pros and cons of currently available diagnostic strategies.

ISSN:1068-3097    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Older reports of greater diabetes-associated increment in cardiovascular disease in women compared with men are confirmed in the recent reports of the Strong Heart Study of Native Americans. In that study, a greater apoprotein B level was seen in diabetic women, in keeping with a greater triglyceride, very low density lipoprotein C (VLDL-C), and lower high density lipoprotein C (HDL-C) level compared to men in previous studies. Greater total and low density lipoprotein (LDL) cholesterol levels may be seen as well. Lipoprotein abnormalities in diabetic women also predict the development of significant albuminuria in diabetic women compared with men and the development of diabetes itself which is a problem. Therapeutic interventions involving walking, triple drug therapy, and postmenopausal estrogen all offer promise. Major cardiovascular prevention trials have shown benefits in diabetic subjects but also have not differentiated response by gender. Such studies are greatly needed because of the greater degree of dyslipidemia and cardiovascular risk in diabetic women.

ISSN:1068-3097    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Deficient insulin secretion and relative hyperproinsulinemia are characteristic of non–insulin-dependent diabetes. Culture of human islets at high glucose concentrations generates β-cell dysfunctions that mimic those observed in diabetic patients, with depleted islet insulin stores. The increased proinsulin ratio probably results from accelerated discharge of insulin granules, rather than diminished expression of convertase. Insulin mRNA levels are decreased, and the rate of transcription of the human insulin gene is suppressed. In human islets exposed to high glucose for 4 to 9 days, the DNA binding of PDX-1, the key transcriptional factor of the insulin gene, is reduced, as is its mRNA level. These effects are reversed by normalizing the culture glucose concentration. It is proposed that β-cell “glucotoxicity” results from the inability of proinsulin biosynthesis to keep pace with chronic insulin hypersecretion. At least in human β-cells, downregulation of PDX-1 expression by hyperglycemia is the main cause for depletion of the insulin stores.

ISSN:1068-3097    

出版商:OVID    

年代:2000

数据来源: OVID