Clinical implication of multiple risk factor control in the management of diabetic macrovasucular complications.

Using cross-sectional and prospective analyses, the risk factors for macroangiopathy (MA) in nonobese Type 2 diabetic patients were evaluated. In the cross-sectional study, we determined a cutoff point for each variable at which changes in the prevalence of total MA reached statistically significant levels. In the prospective study, those who met more than four out of seven control criteria as set forth in the Multiclinical Study for Diabetic Macroangiopathy (MSDM) had less risk of MA in Type 2 diabetes initially diagnosed without MA compared with those who fulfilled less than three factors. These results suggest that multiple risk factor control is the most effective and reasonable way to lower the incidence of MA in Type 2 diabetes.

Theoretical study for volume changes associated with the helix-coil transition of peptides.

We calculate the partial molar volumes and their changes associated with the coil(extended)-to-helix transition of two types of peptide, glycine-oligomer and glutamic acid-oligomer, in aqueous solutions by using the Kirkwood-Buff solution theory coupled with the three-dimensional reference interaction site model (3D-RISM) theory. The volume changes associated with the transition are small and positive. The volume is analyzed by decomposing it into five contributions following the procedure proposed by Chalikian and Breslauer: the ideal volume, the van der Waals volume, the void volume, the thermal volume, and the interaction volume. The ideal volumes and the van der Waals volumes do not change appreciably upon the transition. In the both cases of glycine-peptide and glutamic acid-peptide, the changes in the void volumes are positive, while those in the thermal volumes are negative, and tend to balance those in the void volumes. The change in the interaction volume of glycine-peptide does not significantly contribute, while that of glutamic acid-peptide makes a negative contribution.

Involvement of a CbbR homolog in low CO2-induced activation of the bicarbonate transporter operon in cyanobacteria.

The cmpABCD operon of Synechococcus sp. strain PCC 7942, encoding a high-affinity bicarbonate transporter, is transcribed only under CO2-limited conditions. In Synechocystis sp. strain PCC 6803, the slr0040, slr0041, slr0043, and slr0044 genes, forming an operon with a putative porin gene (slr0042), were identified as the cmpA, cmpB, cmpC, and cmpD genes, respectively, on the basis of their strong similarities to the corresponding Synechococcus cmp genes and their induction under low CO2 conditions. Immediately upstream of and transcribed divergently from the Synechocystis cmp operon is a gene (sll0030) encoding a homolog of CbbR, a LysR family transcriptional regulator of the CO2 fixation operons of chemoautotrophic and purple photosynthetic bacteria. Inactivation of sll0030, but not of another closely related cbbR homolog (sll1594), abolished low CO2 induction of cmp operon expression. Gel retardation assays showed specific binding of the Sll0030 protein to the sll0030-cmpA intergenic region, suggesting that the protein activates transcription of the cmp operon by interacting with its regulatory region. A cbbR homolog similar to sll0030 and sll1594 was cloned from Synechococcus sp. strain PCC 7942 and shown to be involved in the low CO2-induced activation of the cmp operon. We hence designated the Synechocystis sll0030 gene and the Synechococcus cbbR homolog cmpR. In the mutants of the cbbR homologs, upregulation of ribulose-1,5-bisphosphate carboxylase/oxygenase operon expression by CO2 limitation was either unaffected (strain PCC 6803) or enhanced (strain PCC 7942), suggesting existence of other low CO2-responsive transcriptional regulator(s) in cyanobacteria.

The relationship between risk of hypoglycemia and use of cibenzoline and disopyramide.

OBJECTIVE: A case-control study was carried out to compare the risks of hypoglycemia caused by disopyramide and cibenzoline. METHODS: We selected 91 subjects with hypoglycemia from among 14,156 outpatients who consulted the National Cardiovascular Center (NCVC) and received drug therapy between September 1997 and February 1998. We used the fasting blood sugar (FBS) level of 75 mg/dl or less as the cut-off level to screen for hypoglycemia. For each case, five controls matched for gender and age were selected from the clinical division consulted by relevant subjects. RESULTS: Ninety-one cases and 455 controls were enrolled in this study. Of 91 cases with hypoglycemia, 8 (8.8%) were treated with cibenzoline and 3 (3.3%) with disopyramide. The percentage of cases treated with cibenzoline was greater than that in the controls (1.5%), and the prescription frequency of cibenzoline during the study period was 2%. With adjustment for potential confounding factors using conditional logistic regression, hypoglycemia was significantly correlated with the use of cibenzoline [OR 8.0 (95% CI 1.7-36.8)], insulin [OR 48.4 (95% CI 8.8-267.2)], and thyroid agents [OR 13.0 (95% CI 1.1-160.4)]. An increased risk of hypoglycemia associated with the use of sulfonylureas was not detected. In additional logistic regression analysis, including the variables with individual sulfonylureas, glibenclamide but not gliclazide significantly increased the risk of hypoglycemia. The use of disopyramide did not affect the risk of hypoglycemia. In separate analyses for diabetic and non-diabetic patients, the risks of hypoglycemia associated with the use of drugs other than beta-blocking agents in non-diabetic patients were estimated to be lower than those in diabetic patients. CONCLUSION: The use of cibenzoline was significantly correlated with an increased risk of hypoglycemia.

Insulin resistance in diabetic microangiopathies.

To investigate whether insulin resistance is associated with diabetic microangiopathies in type 2 diabetes mellitus, insulin sensitivity was measured in 133 type 2 diabetic subjects with or without diabetic retinopathy and/or nephropathy. Insulin sensitivity was measured by steady-state plasma glucose method or euglycemic glucose clamp method. Regarding retinopathy, in the insulin-resistant group, advanced retinopathy (preproliferative and proliferative retinopathy) was more frequently observed compared with the insulin-sensitive group (significance: p<0.02). Similarly, as for nephropathy, the occurrence of continuous proteinuria in the insulin-resistant group was significantly (p<0.01) more frequent compared with the insulin-sensitive group. Insulin sensitivity expressed as glucose utilization and glucose clearance was significantly (p<0.05) lower in diabetic subjects with retinopathy (without nephropathy) compared with subjects without the microangiopathies after adjustment for age, body mass index (BMI), fasting blood glucose (FBS), and diabetic duration. Similarly, insulin sensitivity in subjects with nephropathy (without retinopathy) was significantly (p<0.05) decreased compared with those without microangiopathies. Furthermore, insulin resistance was significantly (p<0.01) severe in the subjects with both retinopathy and nephropathy than in those without the two microangiopathies. Insulin resistance of type 2 diabetes is closely associated with the progression of microangiopathies, and causal relationship between insulin resistance and microangiopathies has remained to be solved.

Hyperapobetalipoproteinemia with compositional abnormality of LDL and IDL, a characteristic lipoprotein alteration in essential hypertension.

The number and composition of apoprotein B (apoB)-containing lipoproteins that are very low density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), and low-density lipoprotein (LDL) have been analyzed in subjects with essential hypertension who have no obesity and glucose intolerance. Twenty-three essential hypertensive subjects without diabetes mellitus and obesity were recruited. VLDL, IDL, LDL, and high-density lipoprotein (HDL) were separated by ultracentrifugation in the 23 hypertensive and 17 healthy subjects (control group). ApoB was determined by highly sensitive latex agglutination method in each lipoprotein fraction. There were no significant differences in age and body mass index between the hypertension and control groups. In hypertension, cholesterol levels significantly increased in plasma (13%, P < .05) and in LDL (20%, P < .05), but decreased in HDL (-14%, P < .05). Triglyceride significantly increased in plasma (66%, P < .05) and in VLDL (105%, P < .05). ApoB also significantly increased in plasma and all lipoprotein fractions except HDL. (plasma, 35%; VLDL, 94%; IDL, 82%; LDL, 42%; P < .05). With respect to lipoprotein composition, the ratio of cholesterol to apoB significantly decreased in IDL (P < .05) and LDL (P < .05). In essential hypertension, the number of apoB-containing lipoproteins (VLDL, IDL, LDL) all increased. A low ratio of cholesterol to apoB without changes in the ratio of triglyceride to apoB was noted in IDL and LDL, indicating the presence of small dense lipoprotein particles. Characteristic disorders of pure essential hypertension are characterized by hyperapobetalipoproteinemia and small dense LDL.

Association of insulin resistance with salt sensitivity and nocturnal fall of blood pressure.

Insulin resistance was demonstrated in hypertensive patients and in salt-sensitive subjects. It was recently reported that the salt-sensitive state was related to a reduced fall in blood pressure during the night in essential hypertension. In the present study, the relationship among insulin sensitivity, blood pressure response to salt intake, and nocturnal fall in blood pressure was examined in 20 subjects with nondiabetic and nonobese essential hypertension during a low-salt and a high-salt diet. The subjects were maintained on a low-salt diet (50 mmol/d) and a high-salt diet (255 mmol/d) for 1 week each, in random order. On the sixth day of each diet, blood pressure was measured every hour for 24 hours with an automatic device. Insulin sensitivity was measured according to the steady-state plasma glucose (SSPG) method on the seventh day of each diet. Salt-induced increase in blood pressure, which we defined as the change in 24-hour mean arterial pressure between the low and the high dietary salt intakes, was significantly correlated with SSPG (r=0.60, P<0.01) during the high-salt period. There was a significant negative correlation (r=-0.61, P<0.01) between SSPG and a nocturnal fall in mean arterial pressure during the high-salt period. Salt-induced increase in blood pressure was inversely correlated with a nocturnal fall in mean arterial pressure (r=-0.52, P<0.02) with the high-salt diet. These results suggest that insulin resistance, salt sensitivity, and failed nocturnal fall in blood pressure are associated with each other in subjects with essential hypertension.

Evaluation of factors during OGTT to correlate insulin resistance in non-diabetic subjects.

The correlation between various factors obtained during oral glucose tolerance tests (OGTT) and insulin sensitivity tests (steady state plasma glucose, SSPG method) were analyzed in non-diabetic subjects by Pearson's simple correlation. Similar data were obtained for normal as well as normal and impaired glucose tolerance (IGT) subjects. Three factors (AUCI(120)0AUCG(120)0, AUCI(120)0 and AUCI(120)60, area of under curve (AUC), insulin (I), glucose (G)) were found to have significant correlation (r=0.47-0.54) with SSPG, thus indicating insulin resistance. Those with hyperinsulinemia were noted to have insulin resistance with high precision (98%), but insulin resistant subjects without hyperinsulinemia were all judged to have normal sensitivity. These three factors all had high specificity (98%), but low sensitivity (21-25%) with false negative results being obtained in 75-78%, and false positive results in less than 2%. It was difficult to distinguish positive and negative for the insulin resistance by receiver operating characteristic (ROC) curve of I0G0. The sensitivity of which was 12.8% and specificity 93.8%. By ROC curve, the specificities and sensitivities for the proposed factors, including homeostatic model assessment (HOMA) product (I0G0, I0-120, G0-120, insulin and glucose at 0-120' during OGTT) ranged from 60 to 70%, which is far from an acceptable level of 90% or more. Therefore, these factors were useful to correlate insulin sensitivity with OGTT results in hyperinsulinemic subjects or in general non-diabetic subjects, but less useful when it came to identifying individual cases with insulin resistance. These parameters should be used only in non-diabetic subjects and their significance is thought to be restricted to cases with hyperinsulinemia.

Effect of bezafibrate treatment on the altered lipoprotein profiles in hypertriglyceridemic subjects.

The effects of bezafibrate treatment on lipoprotein metabolism were investigated in hypertriglyceridemic subjects. Bezafibrate, a fibric acid derivative, was administered at 200-400 mg/day to 8 patients with hyperlipoproteinemia (type IIb and IV) for 3-6 months. We evaluated the effects of bezafibrate on the plasma levels of total cholesterol(chol), triglyceride(TG), and apoB. In addition, the lipid and apoB contents were also analyzed in VLDL, IDL, LDL and HDL fractions before and after the treatment. It was revealed that plasma levels of chol, TG and apoB significantly decreased after the treatment, 236.3 vs 210.9,192.4 vs 90.2 (p< 0.01) and 129.8 vs 116.2 (p<0.05) mg/dl respectively. VLDL-chol, VLDL-TG and VLDL-apoB dropped from 26.5,127.6 and 11.1 mg/dl to 9.1, 49.5 and 6.7 mg/dl respectively after the treatment. Regarding qualitative alterations of VLDL, TG/apoB, chol/apoB and TG + chol/apoB ratios in VLDL were significantly reduced, indicating that the size of VLDL was diminished by the treatment. In addition, HDL-chol increased from 40.4 to 60.8 mg/dl after the treatment. Consequently LDL-chol/HDL-chol significantly decreased. In conclusion, bezafibrate administration decreased the TG, chol and apoB content in VLDL, suggesting a reduced number of VLDL. Significant rise of HDL-chol and decrease of LDL-chol/HDL-chol are additional beneficial effects following bezafibrate treatment.

A close association between insulin resistance and dehydroepiandrosterone sulfate in subjects with essential hypertension.

To examine the serum levels of dehydroepiandrosterone sulfate (DHEAS) and its relation with insulin resistance and the other risk factors in essential hypertension, serum DHEAS and insulin sensitivity were assessed in 35 male hypertensive and 17 male healthy control subjects aged 50-59 years. Fasting plasma insulin and the area under curve of plasma insulin were determined during a 75 g oral glucose tolerance test. Insulin sensitivity was measured by the steady state plasma glucose method. Fasting plasma insulin and the area under curve of plasma insulin were significantly higher in the hypertensive group than in control group. Steady state plasma glucose was significantly higher in hypertensive subjects indicating insulin resistance compared with control subjects. On the other hand, fasting serum DHEAS levels were significantly lower in the hypertensive group than in the control group. Fasting serum DHEAS levels were inversely correlated with steady state plasma glucose significantly (p=0.0008), indicating a close association between DHEAS levels and insulin resistance. Fasting serum DHEAS was inversely correlated with systolic blood pressure and fasting plasma insulin. In multiple regression analysis of hypertensive subjects, steady state plasma glucose was the strongest determinant of the fasting serum level of DHEAS, followed by systolic blood pressure and fasting plasma insulin. These 3 factors accounted for 51.6% of the variation in DHEAS. In nonobese and nondiabetic essential hypertension, serum DHEAS was lower and insulin resistance was the most significant independent determinant of reduced serum DHEAS, followed by systolic blood pressure and fasting plasma insulin.

Improvement of insulin resistance in essential hypertension by long-acting Ca antagonist benidipine.

To investigate whether the long-acting Ca channel blocker, benidipine improves insulin resistance in patients with essential hypertension, insulin sensitivity was measured using the steady state plasma glucose (SSPG) method in 11 or 14 nonobese and nondiabetic hypertensive subjects before and after treatment with benidipine or placebo, respectively, and 11 healthy control subjects. SSPG level was significantly higher in two hypertensive groups, indicating reduced insulin sensitivity than in controls. SSPG level significantly decreased after benidipine treatment, with a decrease of blood pressure. SSPG level and blood pressure did not change in the placebo group. As for oral glucose tolerance test, the area under the curve of insulin diminished significantly after benidipine treatment. SSPG level significantly correlated with intra-platelet Ca2+ concentrations in 9 hypertensive subjects. The long-acting Ca channel blocker benidipine has partially improved insulin resistance in essential hypertension, contributing to the prevention of atherosclerosis associated with insulin resistance.

Effect of carbohydrate intake on serum 3,5,3'-triiodothyronine-response to glucose ingestion and its relation to glucose tolerance in lean non-insulin-dependent diabetic patients.

This study was conducted to know the effect of carbohydrate intake on serum 3,5,3'-triiodothyronine (CAS 6893-02-3, T3)-response to glucose ingestion and its relation to glucose tolerance in lean non-insulin-dependent diabetes mellitus (NIDDM) patients. Ten patients, body mass index: 21.8 +/- 2.2 (mean +/- SD) kg/m2, were given a control diet (2012 kcal/day(d); carbohydrate (CHO): 299 g/d) on admission. Several days later, they were given a low-calorie and low-CHO diet (Low-CHO) (1156 kcal/d; CHO: 139 g/d) and 2 weeks later, they received a low-calorie and high-CHO diet (High-CHO) (1154 kcal/d; CHO: 176 g/d) and another 2 weeks later, they were given Low-CHO again for 2 weeks. They received oral 75 g glucose tolerance tests after completion of each diet. sigma dGlucose (mmol/l) decreased from 54.3 +/- 11.9 (control) to 42.5 +/- 7.5 after Low-CHO and reached 34.5 +/- 10.4 after High-CHO but increased to 36.4 +/- 11.1 after the 2nd Low-CHO (F = 7.46, p = 0.0005). sigma dT3 (nmol/l) increased from -0.18 +/- 0.52 (control) to 0.12 +/- 0.67 after Low-CHO and reached 0.92 +/- 0.59 after High-CHO but decreased to 0.36 +/- 0.65 after the 2nd Low-CHO (F = 5.92, p = 0.0022). Serum insulin and body weight remained unchanged throughout the study. Negative correlation between sigma dT3 and sigma dGlucose (r = -0.493, n = 40, p = 0.0012) was found throughout the diet modification. Carbohydrate intake affected serum T3-response to glucose ingestion and the response was closely related to glucose tolerance in lean NIDDM patients.

Development of approximate formula for LDL-chol, LDL-apo B and LDL-chol/LDL-apo B as indices of hyperapobetalipoproteinemia and small dense LDL.

Estimation of LDL-chol and LDL-apo B is useful for the diagnosis of hyperapobetalipoproteinemia (normal LDL-chol with increased LDL-apo B), which is one of the most commonly occurring lipoprotein disorders associated with atherosclerotic cardiovascular diseases. The LDL-chol/LDL-apo B ratio reflects the level of small dense LDL, which is an important risk factor for IHD, CVD and ASO. In order to estimate LDL-apo B and LDL-chol/LDL-apo B ratio from blood chol, TG, HDL-chol and apo B values, we developed a formula for LDL-chol ¿0.94Chol- 0.94HDL-chol - 0.19TG¿, LDL-apo B ¿apo B - 0.09Chol + 0.09HDL-chol-0.08TG¿, and LDL-chol/LDL-apo B [¿0.94Chol-0.94HDL-chol - 0.19TG¿/¿apo B - 0.09Chol + 0.09HDL-chol-0.08TG¿] using ultracentrifugal data from 2179 subjects. These were calculated by the least squares method on the assumption that a certain compositional relationship exists between Chol, TG and apo B in VLDL, IDL and LDL. Friedewald's formula for LDL-chol (Chol - HDL-chol - 0.2TG) includes IDL-chol, but the present new formula theoretically excludes IDL-chol. It suggests a better estimation for the correct LDL-chol. Estimated LDL-apo B is useful for the diagnosis of hyperapobetalipoproteinemia and detection of small dense LDL. Without performing ultracentrifuge, additional information is obtained for the quantitative and qualitative alteration of LDL, such as small dense LDL. The above formulae and a new classification of lipoproteinemia including apo B were applied to the analyses of lipoprotein profiles of subjects with cardiovascular diseases, which were compared with those in the general population. Hyperapobetalipoproteinemia with high TG was observed 2-3 times more frequently in subjects with CAD, MI and ASO than in the Suita population. Lower ratios of LDL-chol/LDL-apo B, reflecting preponderance of small dense LDL, were observed in the above three groups. Type IIb and combined low HDL-chol were also frequent phenotypes in CAD, A-Th and ASO. The present formulae are useful for the detailed analyses of lipoprotein disorders in both qualitative as well as quantitative aspects.

Lipoprotein disorder in brain infarction and hemorrhage.

The cholesterol, triglyceride, and apolipoprotein B content of very low-, intermediate-, low-, and high-density lipoprotein fractions (separated by ultracentrifugation) and plasma were measured in healthy controls and patients with atherothrombotic infarction (26), lacunar infarction (26), and brain hemorrhage (14). In both atherothrombotic and lacunar infarction, increased plasma and low-density lipoprotein apolipoprotein B and a decreased low-density lipoprotein cholesterol/apolipoprotein B ratio were noted. In brain hemorrhage patients, a decreased ratio was also observed. These findings suggest that increased small dense low-density lipoprotein is a characteristic risk factor for atherothrombotic and lacunar infarction.