Association of genetic variations near P2 promoter of the hepatocyte nuclear factor-4alpha gene and insulin secretion index in Thais

This study was aimed to assess the association of the two single nucleotide polymorphisms (SNPs) near P2 promoter (rs1884614 and rs2144908) of hepatocyte nuclear factor-4alpha (HNF4A) with insulin secretion index and type 2 diabetes in Thais. Participants were categorized into three groups; unrelated type 2 diabetes (N = 219), prediabetes subjects (N = 228), and normal glucose tolerant controls (N = 203). Homeostasis model assessment was calculated for individual insulin secretion and insulin sensitivity index. Genotyping of both SNPs was done by allele-specific PCR technique. Difference of SNP allele frequencies between groups were computed using the chi (2)-statistic. Multivariate regression analysis was performed to determine the effect of SNPs on insulin secretion index. The clinical features of all groups were similar. We demonstrated genotype TT at rs1884614, BMI, and waist circumference were significantly associated with insulin secretion index (P = 0.023) but not with diabetes phenotype.

Prevalence of type 2 diabetes mellitus and impaired glucose tolerance in Asian women with polycystic ovary syndrome

OBJECTIVES

To determine the prevalence of abnormalities of glucose metabolism in Asian women with polycystic ovary syndrome (PCOS) and to assess the different impacts of the 1985 and 1999 WHO consultations and the ADA criteria for the diagnosis of type 2 diabetes mellitus (DM).

METHODS

Eighty-five women with PCOS were consecutively included in the study at the Reproductive Endocrinology Unit, Department of Ob-Gyn, Ramathibodi Hospital, Mahidol University. All women underwent a standard oral glucose tolerance test (OGTT). Fasting insulin and testosterone levels were also measured.

RESULTS

Seventy-nine women consented to the OGTT. The prevalence of impaired glucose tolerance (IGT) and type 2 DM was 22.8 and 15.2% with the 1985 WHO criteria, and 20.3 and 17.7% according to the 1999 WHO consultation criteria, respectively. The recommendation of the ADA using the fasting glucose levels could only determine a prevalence of 6.3% for type 2 DM. The fasting insulin and testosterone levels were significantly higher in DM than IGT and normal glucose tolerance (NGT) subgroups. The PCOS women with abnormalities of glucose metabolism had a greater body mass index (BMI), higher fasting glucose and 2-h post-load glucose levels than those with NGT. The prevalence of glucose intolerance significantly increased with BMI.

CONCLUSIONS

Similar to other ethnic populations, Asian women with PCOS are at risk of developing IGT and type 2 DM especially if obese. The recommendation of the ADA is not appropriate for the diagnosis of type 2 DM in PCOS women.

A simple prediction rule and a neural network model to predict pancreatic beta-cell reserve in young adults with diabetes mellitus

In the present study we developed and assessed the performance of a simple prediction rule and a neural network model to predict beta-cell reserve in young adults with diabetes. Eighty three young adults with diabetes were included in the study. All were less than 40 years old and without apparent secondary causes of diabetes. The subjects were randomly allocated to 2 groups; group 1 (n = 59) for developing a prediction rule and training a neural network, group 2 (n = 24) for validation purpose. The prediction rule was developed by using stepwise logistic regression. Using stepwise logistic regression and modification of the derived equation, the patient would be insulin deficient if 3(waist circumference in cm) + 4(age at diagnosis) < 340 in the absence of previous diabetic ketoacidosis (DKA) or < 400 in the presence of previous DKA. When tested in the validation set, the prediction rule had positive and negative predictive values of 86.7 per cent and 77.8 per cent respectively with 83.3 per cent accuracy while the ANN model had a positive predictive value of 88.2 per cent and a negative predictive value of 100 per cent with 91.7 per cent accuracy. When testing the performance of the prediction rule and the ANN model compared to the assessment of 23 internists in a subgroup of 9 diabetics whose age at onset was less than 30 years and without a history of DKA, the ANN had the highest ability to predict beta-cell reserve (accuracy = 88.9), followed by the prediction rule (accuracy = 77.8%) and assessments by internists (accuracy = 60.9%). We concluded that beta-cell reserve in young adults with diabetes mellitus could be predicted by a simple prediction rule or a neural network model. The prediction rule and the neural network model can be helpful clinically in patients with mixed clinical features of type 1 and type 2 diabetes.

Diabetes mellitus in young Thai adults

The purposes of the present study were to 1) find the prevalence of various types of diabetes; 2) determine the prevalence of glutamate decarboxylase autoantibody (anti-GAD) and 3) identify clinical characteristics which may help in predicting insulin deficiency in young Thai adults with diabetes. Subjects consisted of 93 adults with diabetes mellitus aged 15-40 years. In each subject, basal and post glucagon C-peptide levels were determined by radioimmunoassay. Anti-GAD was measured by radioimmunoassay and mitochondrial 3243 tRNA(Leu(UUR)) gene mutation was detected by PCR-RFLP. Data were expressed as mean +/- SEM. The mean age of subjects was 31.0 +/- 0.7 years with age at diagnosis of 25.6 +/- 0.9 years. Thirty nine (41.9%) were males and 54 (58.1%) were females. Pancreatic calcification was found in 7 (7.5%) of the patients while 2 (2.2%) were identified as having Wolfram syndrome. Four (4.3%) had nonketotic diabetes with affected family members in multiple generations consistent with MODY. Mitochondrial 3234 tRNA(Leu(UUR)) gene mutation was detected in only one patient. After excluding 14 subjects with pancreatic calcification, Wolfram's syndrome, MODY or mitochondrial gene mutation, 45 (57.0%) were found to be insulin-deficient and 34 (43.0%) were insulin-sufficient based on post-glucagon C-peptide levels. Using stepwise logistic regression analysis, it was found that younger age at diagnosis (p<0.001), smaller waist circumference (p<0.01), previous history of DKA (p<0.01) was significantly associated with insulin deficiency. After excluding patients with DKA, younger age at diagnosis of diabetes (p<0.05) and lower BMI (p<0.01) were related to insulin deficiency. Concerning the role of autoimmunity, it was found that 13 (28.3%) of insulin-deficient subjects were positive for anti-GAD while 4 (11.8%) of those who were insulin-sufficient had positive results. Of the 54 patients currently on insulin, 42 (77.8%) are insulin deficient and 14 (25.9%) have positive anti-GAD. There were 10 (18.5%) who were both insulin sufficient and negative for anti-GAD suggesting that insulin therapy may not be required. We concluded that about half of young Thai adults with diabetes are not insulin-deficient and treatment with insulin may be unnecessary. The prevalence of glutamate decarboxylase antibody and mitochondrial 3234 tRNA(Leu(UUR)) gene mutation is low and as yet undefined factors are accountable for insulin deficiency in a significant number of patients.

Correlation between serum insulin and features of metabolic syndrome in Thais

Several clinical and metabolic abnormalities, i.e. central obesity, hypertension, impaired glucose tolerance or diabetes and dyslipidemia often cluster together and are commonly found in patients with atherosclerotic cardiovascular disease. Hyperinsulinemia and insulin resistance are often evident in subjects with these metabolic abnormalities, so called insulin resistance or metabolic syndrome. In the present study, we looked into the correlations between serum insulin or index of insulin sensitivity and various clinical and metabolic abnormalities. Subjects consisted of 103 males and 118 females. Oral glucose tolerance test was performed on all subjects. Homeostasis model assessment of insulin sensitivity (HOMA-S) was used to determine insulin sensitivity. In males, HOMA-S was found to be significantly correlated with BMI, plasma glucose, insulin, triglycerides and waist circumference. Male subjects in the highest quartile of HOMA-S also had significantly higher systolic blood pressure compared to those in the lowest quartile. In females, HOMA-S was significantly correlated with BMI, blood pressure, plasma glucose, insulin, triglycerides, HDL-cholesterol, waist circumferences and waist-hip ratio. However, after adjustment for BMI, correlation between HOMA-S and blood pressure in women was no longer statistically significant. We, therefore, concluded that correlations between serum insulin or index of insulin sensitivity with certain metabolic abnormalities also existed in Thai subjects. Some of these correlations seem to be at least in part dependent on obesity.

Relation of beta3-adrenergic receptor gene mutation to total body fat but not percent body fat and insulin levels in Thais

A Trp64Arg mutation in the beta3-adrenergic receptor gene has been implicated in the pathophysiology of non-insulin-dependent diabetes mellitus and obesity. However, the findings have been controversial due to the use of different populations and different methods for the estimation of body fat. In the present study, the prevalence of Trp64Arg mutation of the beta3-adrenergic receptor gene was determined and its relation to body fat as assessed by dual-energy x-ray absorptiometry (DEXA) was evaluated in Thai men and women. The effect on insulin sensitivity as assessed by the serum insulin to glucose ratio was also examined. The subjects were 76 men and 135 women aged 20 to 80 years. Body fat and its regional distribution were assessed by DEXA. Mutation in the beta3-adrenergic receptor gene was determined by polymerase chain reaction (PCR)-restriction fragment length polymorphism. Data are expressed as the mean +/- SEM. Fifty-nine subjects (28.0%) had the Trp64Arg mutation in the beta3-adrenergic receptor gene; 54 (25.6%) were heterozygotes and five (2.4%) were homozygotes. The gene frequency of Trp64Arg mutation was 15.2% in these subjects. In women, Trp64Arg mutation was not associated with the difference in total body fat (Trp/Arg or Arg/Arg, 19.4 +/- 1.0 kg; Trp/Trp, 19.2 +/- 0.6 kg) or percent body fat (Trp/Arg or Arg/Arg, 34.6% +/- 1.2%; Trp/Trp, 34.3% +/- 0.6%). In contrast to the findings in women, men with Trp64Arg mutation had lower total body fat after controlling for age (Trp/Arg or Arg/Arg, 13.2 +/- 1.1 kg; Trp/Trp, 15.8 +/- 0.7 kg; P < .05). However, no difference was found in percent body fat (Trp/Arg or Arg/Arg, 20.9% +/- 1.3%; Trp/Trp, 23.3% +/- 0.7%). No difference in the fasting insulin resistance index (FIRI) was found between subjects with and without Trp64Arg mutation. The data suggest that Trp64Arg mutation of the beta3-adrenergic receptor is common in Thais and appears to exert effects on total body fat but not percent body fat in men. Trp64Arg mutation is not associated with insulin resistance as assessed by the FIRI in Thais.

The effects of oestrogen exposure on bone mass in male to female transsexuals

OBJECTIVE

The importance of oestrogen on bone mineral density (BMD) in males was suggested by reports of patients with oestrogen resistance and aromatase deficiency who demonstrated osteoporosis and epiphyseal plate maturation defect despite high testosterone levels. In the present study, we examined the effects of oestrogen exposure on BMD in transsexual men.

DESIGN

Cross-sectional study of BMD in male to female transsexuals.

PATIENTS

Subjects consisted of two groups of transsexual male dancers aged 16-34 years who did not receive transsexual operations (n = 28). Group 1 (n = 11) and group 2 (n = 17) had used oestrogen for 2 years or less and more than 2 years, respectively. Twenty-four healthy adult males served as controls.

RESULTS

Signs of feminization were presented in both group 1 and group 2, with Tanner's stage II-III breast development. BMD at various sites were correlated only to body weight and not to smoking or milk consumption. After controlling for body weight, it was found that group 2 had significantly higher BMD at L2-4 than controls (1.22 +/- 0.03 vs. 1.14 +/- 0.03 g/cm2, P < 0.05) and group 1 (1.22 +/- 0.03 vs. 1.08 +/- 0.04 g/cm2, P < 0.05). BMD at femoral neck was also higher in group 2 compared to controls (1.10 +/- 0.03 vs. 1.01 +/- 0.03 g/cm2, P < 0.05) and group 1 (1.10 +/- 0.03 vs. 0.95 +/- 0.04 g/cm2, P < 0.05). Group 1 subjects had lower BMD compared to controls at femoral trochanter (0.70 +/- 0.04 vs. 0.83 +/- 0.03 g/cm2, P < 0.05) and total femur (0.96 +/- 0.05 vs. 1.07 +/- 0.03 g/cm2, P < 0.05).

CONCLUSIONS

Long-term oestrogen exposure transsexual men result in an increase in bone mineral density despite signs of feminization. This suggests that oestrogen has positive effects on bone density in males. The finding of the trend towards reduced bone density in group 1 remains unexplained.

Impediment of the progressions of microalbuminuria and hyperlipidemia in normotensive type 2 diabetes by low-dose ramipril

In a randomized, double-blind, placebo-controlled study, we investigated in normotensive type 2 diabetics with microalbuminuria the effect of ramipril, an ACE inhibitor, on urine albumin excretion and serum lipids. A total of 1,882 patients were screened for urine microalbumin consecutively by dipstick test, Rapi Tex-Albumin test and RIA. The final 28 normotensive and microalbuminuric patients were assigned to receive either ramipril (1.25 mg/d, n = 16) or placebo (n = 12) for 12 weeks. Throughout the study, both groups had no changes in blood pressure, fasting plasma glucose, HbA1C, serum creatinine and electrolytes and no difference in creatinine clearance. At week 12 only the placebo group showed the significant increment of urine albumin excretion and triacylglycerol (30.6 +/- 38.3 to 39.0 +/- 19.7 and 167 +/- 64 to 208 +/- 77 mg/dl, respectively) but the decrement of HDL-cholesterol (46 +/- 16 to 35 +/- 6 mg/dl). During a 3 month period, increased urine albumin excretion was observed in normotensive type 2 diabetes with microalbuminuria who received only placebo. We conclude that ramipril may arrest the progression of albumin excretion and had favorable effects on serum lipids. Ramipril was safe and well-tolerated without untoward side effects during the study period.

Increased functional Na(+)-K+ pump activity in the vasculature of fructose-fed hyperinsulinemic and hypertensive rats

We hypothesized that hyperinsulinemia may alter insulin's ability to stimulate vascular Na+/K(+)-ATPase pump activity and modulate changes in vascular responsiveness associated with hypertension. We measured potassium-induced relaxation as an indicator of Na+/K(+)-ATPase pump activity in isolated femoral arteries from fructose-fed (FF) hyperinsulinemic, Sprague-Dawley rats. FF rats had higher mean arterial blood pressures than did normal diet-fed (NF) rats (FF, 125 +/- 2.2, n = 20, vs. NF, 113.5 +/- 2.5 mmHg, n = 20, p < 0.05) and were hyperinsulinemic (FF, 64 +/- 4 vs. NF, 37 +/- 2, microU/ml insulin, p < 0.01). FF rats were more sensitive to KCl in the Na+/K+ pump bioassay (FF, 0.86 +/- 0.07, n = 21 vs. NF, 1.18 +/- 0.08, n = 17, p < 0.05, expressed as ED50 in mmol/l KCl). Exogenous insulin (100 mU/ml) increased Na+/K+ pump sensitivity in FF rats as compared with a boiled insulin control (insulin 45 +/- 6%, n = 11, vs. control, 11 +/- 7%, n = 13, p < 0.01, expressed as percent increase in sensitivity, i.e., ED50). There were no significant differences in Na+/K+ pump sensitivity between insulin and control responses in the NF animals (insulin 29 +/- 6%, n = 11, vs. control 46 +/- 5%, n = 10, NS). Dose-response curves were obtained in tail and femoral arteries from the same animals to norepinephrine and acetylcholine, basally and after exogenous insulin. FF vessels had reduced sensitivity to norepinephrine as compared with the NF group. Insulin increased sensitivity to acetylcholine-induced relaxations and increased AII-induced contractions in FF-rat vessels. These data suggest that in the FF rat insulin's influence on the vascular Na+/K+ pump is enhanced and may modulate the changes in vascular responsiveness seen in this model.

Impaired in vivo adrenergic responses in diet-induced hypertensive rats

This study was conducted to investigate whether altered vascular responsiveness to vasoactive compounds contributes to the development of hypertension in diet-induced hyperinsulinemic rats. Male Sprague-Dawley rats were randomly assigned to receive high fructose, high sucrose, or standard rat chow for 13-18 wk. Blood pressure was monitored by indirect (tail-cuff) measurements at regular intervals during the diet treatment. Vascular responses to various vasoactive agents were studied both in vivo and in vitro. Blood pressure response, as assessed by direct (intra-arterial) measurement, to graded dose infusions of norepinephrine or angiotensin II or bolus infusion of acetylcholine were determined. In vitro vascular responses of the tail arteries to exogenous norepinephrine were also studied. The fructose- and the sucrose-fed rats had significantly higher blood pressure than controls. Serum insulin levels were also significantly higher in fructose- and sucrose-fed rats than in controls. The blood pressure responses to graded infusions of norepinephrine were significantly less in the fructose-fed rats than in controls. The blood pressure responses to angiotensin II and acetylcholine infusion were not significantly different among the three groups of rats. In vitro studies of vascular reactivity in the tail arteries revealed than the concentration of norepinephrine that produced half-maximal contraction (NE EC50) was significantly higher in the fructose group than control. Thus, impaired vascular responses to exogenous norepinephrine were observed in fructose-fed rats both in vivo and in vitro. This may be due to an adaptation to increased sympathetic nervous activity, or may be a compensatory response to other structural or functional changes that produce hypertension in this model.

Polyglandular autoimmune (PGA) syndromes: report of three cases and review of the literature

Polyglandular autoimmune (PGA) syndrome is caused by autoimmune process in multiple endocrine glands. This usually results in endocrine gland hypofunction, except for the thyroid gland, in which both hyper or hypofunction may occur. The syndrome can be classified into two types, type I and type II, each with distinct clinical characteristics. We report three cases of PGA syndromes. The first patient had type I PGA syndrome, characterized by hypoparathyrodism, primary adrenal insufficiency and primary ovarian failure. She also had chronic mucocutaneous candidiasis, which is the distinct feature in this syndrome. The second patient had type II PGA syndrome, with primary adrenal insufficiency, Hashimoto's thyroiditis and primary ovarian failure. She also had widespread vitilgo. The last patient also had type II PGA syndrome. She had insulin dependent diabetes mellitus, Graves' disease and alopecia areata.

Transformed phenotype conferred to NIH/3T3 cells by ectopic expression of heparin-binding growth factor 1/acidic fibroblast growth factor

Heparin-binding growth factor 1 (HBGF-1), also known as acidic fibroblast growth factor, is a potent mitogen and angiogenic factor found in tissues such as brain, kidney and heart. The genomic and cDNA sequences indicate that HBGF-1 does not have a typical signal peptide sequence. HBGF-1 was shown to be localized to the extracellular matrix of cardiac myocytes, but the mechanism of secretion is not presently known. We have cloned the HBGF-1 cDNA which allowed us to directly test the biological activity, mechanism of secretion and transforming potential of the recombinant protein. A previous report showed that the truncated HBGF-1 confers partial transformed phenotype to the recipient fibroblasts. However, expression of full-length HBGF-1 has not been reported. The HBGF-1 coding sequence was cloned into the retroviral expression vector, SVX, and transfected into NIH/3T3 cells. Transfectants expressing full-length HBGF-1 protein at high levels form foci and grow to a higher cell density than the parental NIH/3T3 cells. Western blotting analysis showed that the recombinant HBGF-1 is a unique band of approximately 20 kDa and can be detected in the cell homogenate but not in the conditioned medium. NIH/3T3 cells were conferred anchorage independence when HBGF-1 was provided exogenously. We showed the transformed cells are capable of growing on soft agar even in the absence of exogenously-provided HBGF-1. Transfected cells expressing HBGF-1 also induced tumor formation when injected into nude mice. Thus NIH/3T3 cells acquired a full spectrum of transformed phenotype when full length HBGF-1 was expressed at high levels.

Plasma prostacyclin (PGI2) in dengue hemorrhagic fever

Dengue hemorrhagic fever (DHF) is an epidemic viral disease. The exact mechanism attributable to platelet and vascular dysfunctions is still obscure. Plasma 6-keto-PGF1a (6KPGF1), the stable metabolite of PGI2 was determined in 60 DHF patients and in 11 non-DHF (NDHF) patients with fever of over 38.5 degrees C to compare with that of 33 normal children (NC) in the same age group (2-15 years). Among 60 DHF patients, 32 had blood obtained during impending shock, whereas blood samples of the remainder were taken during normotension. Their plasma 6 KPGF1 values (mean +/- SE) were 201.06 +/- 12.42 and 132.87 +/- 13.08 pg/ml respectively. All patients had serology positive for acute dengue viral infection. The plasma 6 KPGF1 (mean +/- SE) of 33 NC and 11 - NDHF subjects were 149.82 +/- 4.93 and 108.69 +/- 14.53 respectively. The plasma 6KPGF1 levels of 32 DHF patients with impending shock were significantly higher than those of 28 normotensive DHF patients (p less than 0.005), 33 NC (p less than 0.005) and 11 - NDHF patients (p less than 0.005). However the levels in 28 normotensive DHF patients are not statistically different from the values of 33 NC and 11 - NDHF patients. It is concluded that there is a tendency of excessive PGI2 production in DHF patients during hypotensive crisis.