Type 2 diabetes prevalence and incidence among adults in Taiwan during 1999-2004: a national health insurance data set study

AIM

To evaluate annual prevalence and incidence of Type 2 diabetes and to examine possible trends among adults in Taiwan.

METHODS

A retrospective nationwide longitudinal study using the Taiwan National Health Insurance Research Database collected during 1999-2004. Adult patients aged > or = 20 years old with prevalent and incident Type 2 diabetes were identified using ICD-9-CM diagnostic codes. Age-specific and age-direct-standardized annual incidence and prevalence were calculated to describe their trends in different gender and age group and compared using Poisson regression.

RESULTS

During the study years, the age-standardized prevalence of Type 2 diabetes increased from 4.7 to 6.5% for men and from 5.3 to 6.6% for women. The increasing trends in prevalence were significant and higher among people aged < 40 and > or = 80 years. The age-standardized incidence rates of Type 2 diabetes per 1000 person-years were approximately 7.6 and remain stable for men, but decreasing from 7.7 to 6.9 for women. However, the incidence increased significantly in younger adults aged < 40 years whose relative incidence (RI with 95% confidence interval) was 1.31 (1.20-1.42) for men and 1.04 (1.01-1.08) for women. The incidence trends for people aged > or = 40 years were decreased for men and women. The differences in incidence trends between age groups and between genders were all statistically significant (all P < 0.001).

CONCLUSIONS

This study demonstrated a substantial increasing trend in Type 2 diabetes prevalence during 1999-2004 among adults in Taiwan. Despite the incidence decreased in older people, young men aged 20-40 years were most susceptible to higher incidence of Type 2 diabetes.

Insulin sensitivity and resistin expression in nitric oxide-deficient rats

AIMS/HYPOTHESIS

The aim of this study was to investigate changes in insulin sensitivity and expression of the gene encoding resistin (Retn) in adipocytes from long-term nitric oxide (NO)-deficient rats.

METHODS

Male Sprague-Dawley rats received [Formula: see text]-nitro-L: -arginine methyl ester (L-NAME 0.5 mg/ml) in their drinking water for 4 weeks, while control rats received plain drinking water. During the experimental period, changes in plasma glucose, insulin and C-peptide levels were measured. After administration of L-NAME for 4 weeks, insulin sensitivity was evaluated in vivo and in vitro. An insulin binding assay was also performed to determine the number and binding affinity of insulin receptors in adipocytes. Adipocyte Retn mRNA levels were examined using northern blotting.

RESULTS

Successful induction of NO deficiency was demonstrated by an increase in systemic blood pressure. No difference in plasma glucose levels was found between the two groups. Compared with the control rats, plasma insulin and C-peptide levels were significantly decreased in the NO-deficient rats, and insulin sensitivity was significantly increased. Insulin-stimulated glucose uptake and insulin binding capacity, but not binding affinity, were significantly increased in adipocytes isolated from NO-deficient rats. In addition, adipocyte Retn mRNA levels, but not plasma resistin levels, were significantly decreased in NO-deficient rats, and the Retn mRNA levels were negatively correlated with insulin sensitivity.

CONCLUSIONS/INTERPRETATION

Insulin sensitivity was increased in NO-deficient rats and this was associated with insulin binding capacity and downregulated Retn expression. These findings suggest that NO plays a regulatory role in metabolism. Dysregulation of NO production may result in the development of metabolic disorders.

Surrogate estimates of insulin sensitivity in Chinese diabetic patients and their offspring

AIMS

To evaluate the relationship between surrogate measures of insulin sensitivity and results from euglycaemic insulin clamp in Chinese diabetic patients and their offspring.

METHODS

The study included 59 volunteers from 20 diabetic families. Each participant completed a 75-g oral glucose tolerance test (OGTT) and a euglycaemic insulin clamp. We tested the correlation of surrogate measures of insulin sensitivity with M-values and M/I ratios (the amount of glucose infused during 90-120 min of the clamp was defined as M, and the mean values of plasma insulin during 90-120 min as I) from the euglycaemic insulin clamp. These measures included fasting insulin (FPI), insulin at 120 min of OGTT, insulin area under the curve of OGTT, fasting glucose-to-insulin ratio, homeostasis model assessment for insulin sensitivity (HOMA-IR and HOMA %S) and the Matsuda-DeFronzo index from OGTT.

RESULTS

The Matsuda-DeFronzo index closely correlated to M-value and M/I in 21 diabetic, 38 non-diabetic individuals and the 59 participants overall (with M-value, r = 0.68, 0.84 and 0.84; with M/I, r = 0.71, 0.72 and 0.75, respectively, all P < 0.001). Without OGTT, HOMA %S was a good surrogate index for diabetic (correlated to M-value and M/I, r = 0.71 and 0.68, P = 0.001) and for non-diabetic subjects (to M-value, r = 0.73; to M/I, r = 0.55, both P < 0.001). FPI was as good as HOMA %S and Matsuda-DeFronzo index.

CONCLUSIONS

The Matsuda-DeFronzo index, HOMA %S and FPI are good surrogate estimates of insulin sensitivity in Chinese diabetic subjects and their offspring.

Exacerbation of insulin resistance and postprandial triglyceride response in newly diagnosed hypertensive patients with hypertriglyceridaemia

The purpose of the study is to examine the differences in insulin resistance and postprandial triglyceride (TG) response between hypertensive patients with or without hypertriglyceridaemia. The study is a comparative cohort study with matching. Thirty-one newly diagnosed hypertensive patients without any medication were recruited from a health survey. The participants were further divided into two groups: those with fasting TG <2.26 mmol/L, and those with TG between 2.26 and 5.65 mmol/L. Both groups were matched in age, sex, body mass index and waist circumference. Each patient received a 75-g oral glucose tolerance test, an insulin suppression test, and a 1000 kcal high fat mixed meal test. The hypertriglyceridaemic hypertensive patients had significantly higher fasting insulin, 2-h plasma glucose, 2-h insulin, and steady-state plasma glucose (SSPG) (13.16 +/- 1.87 vs 9.76 +/- 3.18 mmol/L). They also had a greater postprandial TG response to the challenge of mixed meal (DeltaAUC 20.76 +/- 10.06 vs 7.97 +/- 3.18 mmol 8 h/L). The postprandial TG response was closely correlated (r = 0.72-0.95, P < 0.0001) with fasting TG in all hypertensive patients. Both fasting TG levels and postprandial TG response were significantly (P < 0.05) correlated with SSPG. In conclusion, the hypertensive patients with hypertriglyceridaemia were more insulin resistant than those without it. Exacerbation of postprandial hypertriglyceridaemia was identified in these patients. The TG response to the challenge of high fat meal was significantly correlated with fasting TG and insulin resistant in them. The results provide a rationale for the alleviation of insulin resistance and hypertriglyceridaemia in these atherosclerosis-prone hypertensive patients.

Waist circumference predicts insulin resistance in offspring of diabetic patients

The purpose of the study was to identify a good abdominal obesity index for insulin resistance in offspring of diabetic patients. A total of 74 non-diabetic subjects (male =36; female =38) were recruited from a diabetic family study. The waist circumference (W), waist-hip ratio (WHR) and conicity index were used as the abdominal obesity indices. The body mass index (BMI) and indices obtained from bioelectric impedance analysis (BIA) (body fat percentage, fat mass and fat mass index) were used as overall obesity indices. Fasting plasma insulin (FPI), homeostasis model assessment for insulin resistance (HOMA-IR) and Matsuda-Defronzo index from oral glucose tolerance test were chosen as the insulin sensitivity indices. We correlated obesity indices with insulin resistance indices with age and family adjusted. W was closely correlated in both sexes of subjects with Matsuda-DeFronzo index (male, r=-0.661,p<0.001; female, r=-0.419,p=0.026), FPI (male, r=0.614,p=0.001; female, r=0.503,p=0.006) and HOMA-IR (male, r=0.609,p=0.001; female, r=0.472,p=0.011). WHR and its log transformation predicted insulin resistance only in males. BMI as an overall obesity index was in good correlation with Matsuda-DeFronzo index (male, r=-0.646,p<0.001; female, r=-0.469,p=0.012), FPI (male, r=0.711,p<0.001; female, r=0.464,p=0.013) and HOMA-IR (male, r=0.708,p<0.001; female, r=0.469,p=0.012). Overall obesity indices from BIA were similar to BMI to predict insulin resistance. In conclusion, W is a good abdominal obesity predictor of insulin resistance in offspring of diabetic patients in Taiwan.

Suppressed gene expression of adipocyte resistin in an insulin-resistant rat model probably by elevated free fatty acids

Resistin, the peptide specifically secreted from adipocytes, is a hormone antagonistic to insulin action and, thus, may serve as a link between human obesity due to adiposity and insulin resistance associated with type 2 diabetes. To test this hypothesis, we studied the gene expression of resistin in adipocytes isolated from rats fed with a fructose diet which induced insulin resistance. Compared to the control rats (C) on a normal chow diet, the fructose-fed rats (F) developed hyperinsulinemia, glucose intolerance, hypertriglyceridemia and hypertension, a profile reminiscent of the syndrome X of patients with non-insulin-dependent diabetes mellitus (NIDDM). The F rats had significantly elevated plasma free fatty acids (FFA), enlarged epididymal fat pads, and increased adipocyte size compared with the C rats. We examined the glucose transport and the relative quantity of resistin mRNA produced in the adipocytes of these two groups of rats. Compared to the C rats, the F rats had a clearly reduced insulin-stimulated glucose transport. The gene expression of resistin and other adipocyte peptides was measured on the mRNA by semiquantitative RT-PCR; the validity of this technique was established in advance with a rat-fasting and then refeeding experiment. The F rats showed a decreased expression of the resistin gene, whereas gene expression of leptin and angiotensinogen in contrast increased. Free fatty acids were found to suppress the expression of resistin gene in normal rat adipocytes. These results demonstrate that an insulin-resistant instance in the fructose diet rat model exists with the decreased gene expression of resistin.

Growth inhibition of cultured smooth muscle cells by corrosion products of 316 L stainless steel wire

The potential cytotoxicity on vascular smooth muscle cells of corrosion products from 316 L stainless steel, one of most popular biomaterials of intravascular stents, has not been highlighted. In this investigation, 316 L stainless steel wires were corroded in Dulbecco's modified eagle's medium with applied constant electrochemical breakdown voltage, and the supernatant and precipitates of corrosion products were prepared as culture media. The effects of different concentrations of corrosion products on the growth of rat aortic smooth muscle cells were conducted with the [3H]-thymidine uptake test and cell cycle sorter. Both the supernatant and precipitates of corrosion products were toxic to the primary culture of smooth muscle cells. The growth inhibition was correlated well with the increased nickel ions in the corrosion products when nickel concentration was above 11.7 ppm. The corrosion products also changed cell morphology and induced cell necrosis. The cell growth inhibition occurred at the G0/G1 to S transition phase. Similar to our recent study of nitinol stent wire, the present investigation also demonstrated the cytotoxicity of corrosion products of 316 L stainless steel stent wire on smooth muscle cells, which might affect the poststenting vascular response.

Glucose suppresses the enhancement by free fatty acids on thrombin- stimulated production of prostacyclin in cultured aortic endothelial cells

BACKGROUND

Prostacyclin (PGI2) is a potent vasodilator and inhibitor of platelet aggregation. It may reduce in diabetic patients to contribute to the platelet hyperaggregability and acceleration of atherosclerosis. While the major clinical manifestation of diabetes mellitus is increased blood levels of glucose, elevation of free fatty acids (FFA) levels in the circulation has also been reported.

METHODS

Cultured rat aortic endothelial cells were treated with media containing high concentration of FFA (oleic acid 0.5 mM, palmitic acid 0.25 mM, linoleic acid 0.25 mM, stearic acid 0.06 mM, arachidonic acid 0.04 mM, total 1.1 mM, and the molar ratio of FFA/albumin < 2), glucose (22 mM) or both. Then the PGI2 release was studied by measuring 6-keto-PGF1alpha in the media.

RESULTS

We found that high concentration of FFA increased the PGI2 production at basal (1.227 +/- 0.031 vs 0.762 +/- 0.028 ng/mg protein, n = 6, p = 0.002) and when stimulated by 0.5 unit/ml of thrombin (2.708 +/- 0.115 vs 1.337 +/- 0.225 ng/mg protein, n = 6, p = 0.002). Two-day treatment with high-glucose did not affect PGI2 production. However, in the presence of high-glucose, the enhancement by high FFA of thrombin stimulated PGI2 production disappeared (high-glucose 1.461 +/- 0.312 ng/mg, normal-glucose 2.708 +/- 0.115 ng/mg, n = 6, p = 0.002).

CONCLUSIONS

The interaction between glucose and FFA can reduce PGI2 production in thrombin-stimulated state. Our findings further support their role in the pathogenesis of platelet hyperaggregability and acceleration of atherosclerosis in diabetes.

Undiagnosed glucose intolerance encountered in clinical practice: reappraisal of the use of the oral glucose tolerance test

BACKGROUND

In 1997, the Expert Committee of the American Diabetes Association (ADA) revised the diabetes mellitus (DM) diagnostic criteria to facilitate the diagnosis of DM on the basis of fasting plasma glucose (PG). The major purpose of the study is to evaluate if oral glucose tolerance test (OGTT) is still needed after the revision of criteria.

METHODS

From September 1994 to March 1995, 247 ambulatory subjects referred by clinicians for 75-g OGTT were recruited for the study. Fasting and 2-h PG and serum insulin concentrations were determined. Additional fasting blood samples were collected for the measurement of HbA1c. We used the receiver operating characteristic (ROC) curve to locate a cut-point of fasting PG corresponding to 2-h PG of 200 mg/dl.

RESULTS

The optimal fasting PG level depicted by ROC curve was more than 105 mg/dl, giving 80.6% sensitivity and 85.6% specificity for the diagnosis of DM in clinical setting. If fasting PG > or = 126 mg/dl was employed, the specificity was 98.3% but the sensitivity went down to 42.6%. High rates of glucose intolerance would remain undiagnosed in subjects with fasting PG less than 126 mg/dl (41.6% of them being IGT and 38.6% DM), if the OGTT was exempted from clinical practice. HbA1c more than 6.2% could be a clue to recognize undiagnosed DM, but was unable to separate impaired glucose tolerance (IGT) from non-DM.

CONCLUSIONS

In the population studied, undiagnosed glucose intolerance can still be encountered in a large number of subjects with fasting PG less than 126 mg/dl. OGTT is still indispensable in clinical setting for the diagnosis of DM and IGT after the revision of diagnostic criteria.

Abnormal cardiovascular reflex tests are predictors of mortality in Type 2 diabetes mellitus

AIMS

To determine whether diabetic autonomic neuropathy is an important factor contributing to mortality in Type 2 diabetes mellitus.

METHODS

Between 1989 and 1993, 431 men and 181 women with Type 2 diabetes were given diabetic autonomic neuropathy cardiovascular reflex (CVR) tests. These subjects were followed for the subsequent 5--9 years to assess mortality rates.

RESULTS

The prevalence rate of abnormal CVR tests was 46.1% in patients with the history of diabetes less than 5 years and up to 69.4% when the history of diabetes exceeded 20 years. During the follow-up period from 1 January 1989 to 31 December 1997 (mean 7.7 years), a total of 135 participants died. The 8-year survival rate for patients with abnormal CVR tests was 63.6% in males and 76.4% in females, compared with 80.9 and 93.3% for patients with normal CVR tests. The results were grouped as: group 1, normal CVR tests without postural hypotension (PHT); group 2, normal CVR tests with PHT; group 3, abnormal CVR tests without PHT; and group 4, abnormal CVR tests with PHT. The 8-year survival rate was 85.4% in group 1, 80.9% in group 2, 74.5% in group 3 and 61.1% in group 4.

CONCLUSION

Type 2 diabetic patients with abnormal CVR tests may have increased mortality, and those combined with postural hypotension have higher mortality than those without. Abnormal CVR tests may be important predictors of mortality in Type 2 diabetes mellitus.

A comparison of insulin suppression tests performed with somatostatin and octreotide with particular reference to tolerability

To evaluate the tolerability of insulin suppression test (IST) using octreotide instead of somatostatin, we compared the steady-state plasma glucose (SSPG) values and the safety during and after the test in 17 normal volunteers. The subject received IST twice (with somatostatin or with octreotide) in random order. During the test, all subjects were infused with regular insulin and glucose simultaneously for 180 min. In addition, either somatostatin or octreotide was infused intravenously over the same period of time. Plasma glucose, insulin and C-peptide were measured. The subject response to the test was recorded during and one day after the test by a structured questionnaire. The SSPG and the steady-state plasma insulin (SSPI) values reached during IST were similar, irrespective of the use of somatostatin or octreotide. There was a positive correlation between the SSPG values obtained from both methods (r = 0.67, P = 0.003). However, the mean intra-individual coefficient of variation is 17.9% for SSPG. The SSPG levels, no matter from which method, correlated positively with the 2-h insulin after oral glucose challenge. Most adverse events (especially gastrointestinal discomfort) occurred after the test, and increased much more after using octreotide than somatostatin (P = 0.002 by chi 2 test). In conclusion, the SSPG values measured by IST using octreotide or somatostatin are similar in normal healthy subjects. Yet, the octreotide method has more adverse events after the test.

Linoleic acid and oleic acid increase the endothelin-1 binding and action in cultured rat aortic smooth muscle cells

An increase in circulating non-esterified fatty acids (NEFA) has been observed in patients with poorly controlled diabetes mellitus. To investigate whether fatty acids will affect the endothelin-1 (ET-1) receptor and thus contribute to the acceleration of atherosclerosis in diabetic patients, cultured rat aortic smooth muscle cells (SMC) were maintained in media containing higher (similar to those in diabetic patients) concentrations of oleic acid (OA) or linoleic acid (LA). The ET-1 binding and ET-1-stimulated thymidine uptake were then examined. We found that cells treated with OA (500 micromol/L) or LA (250 micromol/L) showed a significant increase in ET-1 receptor amount as demonstrated by Scatchard analysis (Bmax: 7.40 +/- 1.04 v 2.71 +/- 0.54 fmol/mg and 5.00 +/- 1.00 v 3.32 +/- 0.70 fmol/mg, respectively). No change in binding affinity was found. Moreover, both the basal and ET-1-stimulated thymidine uptake were enhanced by treatment with either LA (basal, 11,367 +/- 4,117 cpm/mg; LA, 13,933 +/- 4,003 cpm/mg; ET-1 (10(-8)), 16,931 +/- 4,412 cpm/mg; LA +/- ET-1 (10(-8)), 28,855 +/- 5,217 cpm/mg) or OA (basal, 4,912 +/- 1,193 cpm/mg, OA, 8,027 +/- 1,318 cpm/mg; ET-1 (10(-8)) 9,947 +/- 2,520 cpm/mg; OA + ET-1 (10(-8)), 16,761 +/- 1,740 cpm/mg). This enhancement in thymidine uptake was associated with an increase in cell number. Because ET-1 and its receptor are involved in atherogenesis, our findings suggested that increase in circulating NEFA may contribute to the acceleration of atherosclerosis in diabetic patients. Further studies to confirm its role in the vascular wall are warranted.

The cytotoxicity of corrosion products of nitinol stent wire on cultured smooth muscle cells

Although nitinol is one of most popular materials of intravascular stents, there are still few confirmative biocompatibility data available, especially in vascular smooth muscle cells. In this report, the nitinol wires were corroded in Dulbecco's modified Eagle's medium with constant electrochemical breakdown voltage and the supernatant and precipitates of corrosion products were prepared as culture media. The dose and time effects of different concentrations of corrosion products on the growth and morphology of smooth muscle cells were evaluated with [(3)H]-thymidine uptake ratio and cell cycle sorter. Both the supernatant and precipitate of the corrosive products of nitinol wire were toxic to the primary cultured rat aortic smooth muscle cells. The growth inhibition was correlated well with the increased concentrations of the corrosion products. Although small stimulation was found with released nickel concentration of 0.95 +/- 0.23 ppm, the growth inhibition became significant when the nickel concentration was above 9 ppm. The corrosion products also altered cell morphology, induced cell necrosis, and decreased cell numbers. The cell replication was inhibited at the G0-G1 to S transition phase. This was the first study to demonstrate the cytotoxicity of corrosion products of current nitinol stent wire on smooth muscle cells, which might affect the postimplantation neointimal hyperplasia and the patency rate of cardiovascular stents.

Using semi-automated oscillometric blood pressure measurement in diabetic patients and their offspring

To determine whether a semi-automatic oscillometric blood pressure (BP) monitor Dinamap 1846SX (DIN) can replace the standard mercury sphygmomanometer (SMS) for BP measurements in diabetic patients and their offspring, we compared SMS with DIN in 105 diabetic patients and their families. Their mean age was 50.6 (range 24-86) years, of whom 41 had diabetes mellitus (DM), 32 impaired glucose tolerance and 32 non-DM. After resting quietly for 10 min, their right arm BP were measured twice with each device at random and with 1-min intervals between each measurement. Agreement between measurements was tested by plotting the differences between the methods against means and by intraclass correlation coefficient (r(I)). The DIN was also evaluated by the criteria of American Association for the Advancement of Medical Instrumentation (AAMI), the British Hypertension Society (BHS) criteria and clinical criteria of O'Brien. All measurements by DIN [first readings or averaged readings of duplicate measurements of systolic BP (SBP) or diastolic BP (DBP)] satisfied the AAMI criteria and had good agreement with SMS (r(I)=. 951 for SBP and r(I)=.905 for DBP). The first readings of systolic BP measured by DIN vs. SMS failed to satisfy the criteria by O'Brien and reached BHS grade C level. Other measurements passed the limits of O'Brien and reached BHS grade A or B. In conclusion, averaged readings of duplicate BP measurements by DIN are interchangeable with that by SMS in Chinese diabetic patients and their offspring. Only one single DIN measurement is not acceptable for clinical application.

A novel mutation in the hepatocyte nuclear factor-1alpha/MODY3 gene in Chinese subjects with early-onset Type 2 diabetes mellitus in Taiwan

AIMS

The goal of this study was to determine the frequency of mutation in hepatic nuclear factor (HNF)-1alpha, a gene recently implicated as causing maturity-onset diabetes of the young (MODY) and to analyse the respective clinical presentations in an ethnically Chinese population.

METHODS

Fifteen unrelated subjects (nine females and six males) aged less than 35 years who had early-onset diabetes were analysed to test the possibility that mutation of the HNF-1alpha gene was responsible for this disorder. Genomic DNA extraction, polymerase chain reaction and DNA sequence analysis were performed accordingly.

RESULTS

One patient with MODY had a novel missense mutation in exon 3 of the HNF-1alpha gene (Y218C) in a region of the protein that corresponds to a predicted DNA binding domain.

CONCLUSIONS

A Y218C mutation in HNF-1alpha gene was identified in one family in Taiwan.

Combined use of insulin and endothelin-1 causes decrease of protein expression of beta-subunit of insulin receptor, insulin receptor substrate-1, and insulin-stimulated glucose uptake in rat adipocytes

Previously, we reported that insulin-stimulated glucose uptake (ISGU) can be inhibited by endothelin (ET-1). However, the mechanism by which ET-1 impairs ISGU in adipocytes remains unclear. This study investigated the effects of ET-1 on insulin action in rat adipocytes in order to elucidate the molecular mechanism of action of ET-1 on ISGU. The results show that ISGU was increased fivefold after 3-h treatment with 1 nM insulin. Treatment with 100 nM ET-1 had no effect on basal glucose uptake. However, ET-1 inhibited approximately 25% of ISGU and 20% of insulin binding after 3-h treatment in the presence of 1 nM insulin. Expression of the beta-subunit of the insulin receptor (IRbeta) and the insulin receptor substrate-1 (IRS-1) in adipocytes was not significantly affected by 1 nM insulin or by 100 nM ET-1, even after 3-h treatment. However, expressions of IRbeta and IRS-1 were dramatically decreased in a dose- and time-dependent manner when adipocytes were treated with both insulin and ET-1. Approximately 50% of IRbeta and 65% of IRS-1 expression levels were suppressed when adipocytes were simultaneously treated with both 1 nM insulin and 100 nM ET-1 for 3 h. These results suggest that the inhibitory effect of ET-1 on ISGU may be mediated via the insulin receptor and suppression of IRbeta/IRS-1 expression.

Insulin sensitivity in normotensive offspring of hypertensive parents

OBJECTIVES

To investigate the insulin sensitivity in normotensive offspring of hypertensive parents.

SUBJECTS

Fifteen young normotensive offspring of hypertensive parents were paired with 15 controls matched for age, sex and body mass index.

METHODS

The insulin sensitivity was investigated by 75 g oral glucose tolerance test (OGTT) and modified insulin suppression test. A high-fat mixed meal was administered to observe the changes of TG levels.

RESULTS

The plasma glucose and serum insulin responses to oral glucose challenge were comparable between both groups. High-fat mixed meal made no difference in the plasma glucose, serum triglyceride or insulin between the 2 groups. With the modified insulin suppression test, the steady-state plasma glucose levels (SSPG) were higher in the offspring of parents with essential hypertension (138+/-43 mg/dl) than in the control group (95+/-26 mg/dl). The diastolic blood pressure and heart rate of the offspring of hypertensive parents are also higher than the control group.

CONCLUSIONS

Insulin resistance exists in young normotensive offspring of hypertensive parents, and the impairment of insulin-mediated glucose uptake in these subjects develop before any alteration of fasting and postprandial triglyceride.

Lack of effect of simvastatin on insulin sensitivity in Type 2 diabetic patients with hypercholesterolaemia: results from a double-blind, randomized, placebo-controlled crossover study

AIMS

To evaluate the effects of simvastatin on serum lipids and insulin sensitivity in Type 2 diabetic patients with hypercholesterolaemia.

METHODS

A double-blind, randomized, placebo-controlled and two-period crossover study. After a 2-month run-in, 19 eligible Type 2 diabetic patients with hypercholesterolaemia were randomized to receive either simvastatin or placebo for 3 months, exchanging their treatment thereafter for another 3 months. Blood samples were taken in month 0 and at monthly intervals to measure serum lipids and indices of glycaemic control. An euglycaemic insulin clamp was performed in months 0, 3 and 6 to assess change of insulin sensitivity. The amount of glucose infused during 90-120 min of the clamp (M), and the mean values of serum insulin during 90-120 min (I) were measured. The M and M/I ratio were used to represent the in vivo insulin sensitivity of the subject.

RESULTS

Simvastatin significantly reduced serum total cholesterol (TC) by 23+/-18% and low density lipoprotein-cholesterol (LDL-C) by 30+/-26%. It did not alter glycaemic control. The M-values and M/I ratios were similar in both groups in each period and no drug effect on insulin sensitivity could be identified.

CONCLUSIONS

Simvastatin significantly reduced the serum TC and LDL-C levels without alteration of insulin sensitivity in Type 2 diabetic patients with hypercholesterolaemia.

Octreotide effect on hypersecretion of growth hormone in a patient with fibrous dysplasia: a case report

We report the case of a 17-year-old adolescent boy with polyostotic fibrous dysplasia and hypersecretion of growth hormone (GH). The fasting serum GH, insulin-like growth factor-I (IGF-I), alkaline phosphatase activity and osteocalcin levels were all elevated. The GH secretion was stimulated by thyrotropin-releasing hormone and was not suppressed by an oral glucose test. Magnetic resonance imaging of the sella turcica showed no abnormal findings. The patient was treated with octreotide, 100 micrograms subcutaneous injection three times a day for two weeks to observe the effects of octreotide on growth hormone secretion. GH and IGF-I secretions were suppressed by octreotide therapy, while alkaline phosphatase activity and osteocalcin secretion were partially suppressed. We suggest that the high bone turnover states in this patient may be attributed to both hypersecretion of growth hormone and the polyostotic fibrous dysplasia itself.

Clinical response and patient acceptance of a prefilled, disposable insulin pen injector for insulin-treated diabetes

BACKGROUND

The aim of this study was to evaluate the clinical response and patient acceptance of a prefilled, disposable insulin pen injector (Novolet, Novo-Nordisk, Bagsvaerd, Denmark) for treating insulin-dependent diabetic patients.

METHODS

After a run-in period of six weeks, 19 patients participated in an open, randomized, controlled, crossover study with two 12-week periods using insulin pens or conventional syringes. Clinical responses were assessed every 12 weeks, including glycosylated hemoglobin (HbA1c), seven-point blood glucose profiles and hypoglycemic reactions. At the end of the trial, patients completed questionnaires about their acceptance of the insulin delivery device.

RESULTS

Neither of the regimens rendered significant changes in HbA1c, blood glucose profiles or hypoglycemic episodes. Most of the study subjects reported that the prefilled, disposable devices were convenient and easy to use, and many of them wished to continue using the device for insulin delivery.

CONCLUSIONS

The clinical response was the same for both treatment regimens, but most subjects preferred the prefilled disposable pen injector for insulin delivery because it was more convenient for daily use.

Exogenous hyperinsulinemia causes insulin resistance, hyperendothelinemia, and subsequent hypertension in rats

In many clinical and animal studies, hypertension and insulin resistance coexist, but their mechanistic relationship is unclear. We explored the causal link between these two parameters in a rat model with chronic hyperinsulinemia induced with human insulin (1 U/d) released from subcutaneously implanted minipumps. Rats with saline minipumps served as a control. During the first experiment, plasma levels of insulin and glucose and the systolic blood pressure of the two groups were continuously monitored for 17 days. In the subsequent four experiments, rats were killed on days 10 and 13 to measure plasma endothelin-1 (ET-1) levels and the glucose transport into and insulin and ET-1 binding of isolated adipocytes. In one experiment, rats were tested for oral glucose tolerance on days 10 and 13. In another experiment, ET-1 binding to the aortic plasma membrane was also determined. The results showed that rats became hyperinsulinemic throughout the experimental period by the instillation of exogenous insulin. Hyperinsulinemic rats were consistently hypoglycemic during the first day, but they became euglycemic thereafter, indicating an insulin-resistant state. Glucose intolerance was obvious by day 10, but significant hypertension was not detected until the 11th day on insulin infusion. Compared with the saline controls, insulin-infused rats had an increase of plasma ET-1 levels but a decrease of both basal and insulin-stimulated glucose transport into adipocytes. ET-1 binding to adipocytes of the insulin-infused group was elevated significantly from day 10 through day 13. ET-1 binding to the aortic membranes, supposedly downregulated by the increased plasma ET-1 and hypertension, was similar to that found in the controls on day 13. These results imply that hyperinsulinemia in rats could lead to hypertension via the elevation of plasma ET-1 levels together with an unaltered vascular binding of ET-1, which was probably unrelated to the insulin resistance.

Evidence that endothelin-1 (ET-1) inhibits insulin-stimulated glucose uptake in rat adipocytes mainly through ETA receptors

The specificity of endothelin (ET) receptors involved in the inhibition of insulin-stimulated glucose uptake (ISGU) in rat adipocytes was investigated. Adipocytes were isolated from the epididymal fat pads of Sprague-Dawley rats. To determine receptor subtypes, we used three ET isopeptides, ET-1 and ET-2, both of which are nonselective agonists, and ET-3, a selective agonist for ETC receptors, to displace [125I]ET-1 binding from the fat cells. The efficiency of displacement was ET-1 > ET-2 >> ET-3, indicating that the primary receptors involved belonged to the ETA subtype. At an equal concentration of 1 micromol/L, BQ-610, a selective ETA antagonist, displaced [125I]ET-1 from binding to fat cells, whereas IRL-1038, a selective ETB antagonist, did not. Using [3H]2-deoxy-D-1-glucose ([3H]2-DG) as a tracer in studies of glucose uptake, we found that equimolar BQ-610 completely reversed the inhibitory effect of ET-1 on ISGU, whereas IRL-1038 was ineffective. Northern blot analysis of adipocyte receptors showed abundant mRNA for ETA, but no ETB subtype. These results clearly demonstrate that ETA is the predominant receptor in rat adipocytes.

Overexpression of vascular endothelin-1 and endothelin-A receptors in a fructose-induced hypertensive rat model

OBJECTIVE

To examine the temporal relationship between hyperinsulinemia and hypertension in the fructose-hypertensive rat model and to study the function of endothelin-1 (ET-1) in fructose-induced hypertension.

DESIGN

Since ET-1 induces insulin resistance in conscious rats, we tested the hypothesis that both hyperinsulinemia and hypertension developed in the fructose-hypertensive rat model might be the sequelae of an elevated tissue content of ET-1 and ET(A) receptors.

MATERIALS AND METHODS

Systolic hypertension was induced within 3 weeks in male Sprague-Dawley rats fed on a fructose-rich diet. After continual monitoring of blood pressure and plasma insulin concentrations, the animals were killed at the end of experiment to determine plasma levels of ET-1, the contractile response of aortic rings to ET-1, and ET-1 and ET(A) receptor gene expressions. In a separate experiment, BQ-610 was administered to lower the effect of ET-1 in rats with fructose-induced hypertension.

RESULTS

Compared with control rats given normal chow, the fructose-fed rats developed systolic hypertension after 3 weeks of the diet (127+/-3.7 versus 110+/-5.5 mmHg, P < 0.01) and hyperinsulinemia both before (1 07.1+/-32.5 versus 48.5+/-14.3 pmol/l, P < 0.005) and after (96.6+/-63.7 versus 50.4+/-5.6 pmol/l, P< 0.05) they became hypertensive. Although plasma ET-1 levels did not differ between the rat groups, aortic ring contraction-concentration curves, indicating vessel contractility in response to ET-1, were significantly greater in these rats than in controls (F1,72 = 12.34, P< 0.00077). Messenger RNA extracted from the tail arteries and blotted with both ET-1 and ET(A) probes showed that fructose-fed rats had greater ET-1 and ET(A)-receptor gene expression than control rats. Concomitant administration of BQ-610 to rats fed on a fructose diet significantly reduced the hypertension. Conclusions These findings suggest that elevated vascular expression of ET-1 and ET(A) receptor genes may mediate the development of hypertension and hyperinsulinemia in rats fed a fructose-rich diet

Technical and clinical evaluation of an electrochemistry glucose meter: experience in a diabetes center

The Sensorex (Metertech, Taipei, Taiwan), an electrochemical blood glucose meter, is designed for self-monitoring of blood glucose (BG) concentrations in capillary blood through the use of an electrochemical test strip. The intra-assay coefficients of variation of Sensorex were 5.2, 5.4, and 4.7% at BG levels of 46, 154 and 302 mg/dl respectively. The BG concentrations tested by Sensorex were correlated well with those by YSI method (r approximately/= 0.85, P < 0.0001). The intraclass correlation coefficients (rI) between the results obtained by Sensorex and YSI were 0.84 in capillary blood and 0.69 in venous whole blood, which indicated good agreement between both methods. The Sensorex was evaluated by error grid analysis and revealed 'acceptance' results. In field test, the Sensorex results obtained by lay users were in concordance with those by trained technicians (rI = 0.87). Our data show that the Sensorex glucometer is reliable and easy to use. We also demonstrate a practical clinical approach for the evaluation of a novel SMBG system.

4-Bromocrotonic acid enhances basal but inhibits insulin-stimulated glucose transport in 3T3-L1 adipocytes

Inhibitors of fatty acid oxidation, 2-bromopalmitic acid (Br-C16) and 4-bromocrotonic acid (Br-C4) were examined for their effect on glucose transport in 3T3-L1 adipocytes. Whereas Br-C16 was without effect, Br-C4 augmented basal but inhibited insulin-stimulated 2-deoxyglucose uptake in a dose- and time-dependent manner. Immunoblot analysis indicated that following Br-C4 pretreatment, the content of GLUT1 in plasma membranes was increased whereas insulin-induced translocation of GLUT4 was greatly eliminated. The total cellular amount of GLUT1 or GLUT4, on the other hand, was not altered. Thus these results seem to suggest that Br-C4 has opposite effect on basal and insulin-stimulated glucose transport by a mechanism other than its inhibition of fatty acid oxidation. The translocation processes for both GLUT1 and GLUT4 transporters appears to be altered.

Trilinolein inhibits the adhesion of neutrophils to endothelial cells

1. Trilinolein is a triacylglycerol with linoleic acid as the only type of fatty acid in all three esterified positions of glycerol. It was recently reported to have a myocardial protective effect in coronary ligated rats. We now study its effect on the adhesion of human neutrophils to cultured bovine endothelial cells. 2. Pretreatment of an endothelial monolayer with trilinolein at concentrations ranging from 10(-10) to 10(-6) mol/L significantly inhibited neutrophil adhesion to endothelial cells. Trilinolein was less potent than sodium nitroprusside in inhibiting neutrophil adhesion. 3. The inhibitory effect of trilinolein was antagonized by methylene blue and N(G)-nitro-L-arginine methyl ester. The inhibitory effect of trilinolein was not mediated through linoleic acid because linoleic acid did not inhibit neutrophil adhesion. 4. Pretreatment of neutrophils with trilinolein did not reduce neutrophil adhesion. However, in neutrophils activated with N-formyl-methionyl-leucyl-phenylalanine, trilinolein inhibited the neutrophil adhesion to endothelial cells. 5. We conclude that trilinolein inhibits neutrophil adhesion to the endothelial monolayer by stimulating the nitric oxide and cyclic GMP pathways in endothelial cells. It may also inhibit neutrophil adhesion by scavenging free radicals. The inhibitory effect of trilinolein on neutrophil adhesion may play a role in its myocardial protective activity.

Steroid cell tumors of the ovary: clinical, ultrasonic, and MRI diagnosis--a case report

Steroid cell tumors of the ovary are rare sex-cord neoplasms which account for less than 0.1% of all ovarian tumors. They have been divided into two subtypes according to their cell of origin as follows: stromal luteoma, and Leydig cell tumors, and a third subtype with lineage unknown is a steroid cell tumor, not otherwise specified (NOS). The clinical presentation may take many forms, including pain, abdominal distention and bloating, but perhaps the most interesting and noticeable presentations are those related to the hormonal activity and virilizing properties of the tumor. No radiological features of the steroid cell tumor, NOS have been presented in the literature. This report presents the MRI and ultrasonographic findings of a patient having steroid cell tumor, NOS, of the right ovary with metastasis to the uterus.

Amelioration of insulin resistance and hypertension in a fructose-fed rat model with fish oil supplementation

In type II diabetic patients, one can detect several pathologic changes including insulin resistance and hypertension. Sprague-Dawley rats fed a fructose-rich diet (group F) exhibited these characteristic abnormalities within 2 weeks and were an excellent laboratory animal model for research on insulin action and development of hypertension. Since fish oils containing omega-3 fatty acids have a beneficial effect in preventing atherosclerotic diseases, we performed repeated experiments to test the effects of fish oil supplementation in group F rats. Compared with control rats on a normal diet (group C), group F consistently developed hypertriglyceridemia without elevated plasma free fatty acid (FFA), fasting hyperinsulinemia together with fasting hyperglycemia (insulin resistance syndrome), and systolic hypertension within 3 weeks. Insulin-stimulated glucose uptake and insulin binding of adipocytes were significantly reduced. Rats fed the same high-fructose diet but supplemented with fish oil (group O) had alleviation of all of these metabolic defects and a normalized insulin sensitivity and blood pressure. beta-Cell function as shown by plasma glucose and insulin responses to oral glucose remained intact in group F and group O. The plasma endothelin-1 (ET-1) level and ET-1 binding to adipocytes were not different among the three groups. Based on these results, we suggest that dietary high fructose induced hypertriglyceridemia and insulin resistance with normal islet function, and that the induced hypertension was not associated with plasma ET-1 abnormalities and was probably caused by other undefined pathologic changes that can be prevented by dietary omega-3 fatty acids.

Growth hormone (GH) replacement reduces total body fat and normalizes insulin sensitivity in GH-deficient adults: a report of one-year clinical experience

The effects of GH replacement on body fat composition and insulin sensitivity were assessed in GH-deficient adults. The patients were randomized into a double-blind, placebo-controlled study of human recombinant GH replacement therapy for 6 months (period 1), followed by an open phase of GH for another 6 months (period 2). Anthropometric variables, body fat composition (fat %), and biochemical parameters were measured during the trial. Measurements of in vivo insulin sensitivity were carried out at the commencement of the study and on completion of the trial by modified insulin suppression test. The modified insulin suppression test was performed both in the morning (AM) and in the afternoon (PM) to further evaluate the PM-AM steady-state plasma glucose (SSPG) pattern. We found that the GH-deficient adults had more body fat and were insulin resistant. Significant reduction in fat % and total body fat mass was found in the active arm of period 1 without alteration of body weight. Besides, we demonstrated, for the first time, the GH replacement for 6 months did not alter the insulin sensitivity, but replacement for a longer period (12 months) normalized not only the AM SSPG level but also the PM-AM SSPG pattern. We also found a positive correlation between SSPG (regardless of AM vs. PM) and fat % and total body fat mass. In conclusion, normalization of insulin sensitivity in GH-deficient adults after replacement of GH may be related to the reduction of total body fat.

Acipimox attenuates hypertriglyceridemia in dyslipidemic noninsulin dependent diabetes mellitus patients without perturbation of insulin sensitivity and glycemic control

Hyperlipidemia, hypertriglyceridemia in particular, is a common feature in patients with noninsulin dependent diabetes mellitus (NIDDM) and may associate with insulin insensitivity. Acipimox, being widely prescribed for treating hypertriglyceridemia, is also used in NIDDM patients for their dyslipidemia. In the present study, we evaluated the effect of acipimox in Chinese NIDDM patients with hypertriglyceridemia. A total of 16 patients enrolled in a double-blind, randomized, placebo-controlled and two-period crossover study. After an 8 week run-in period, patients were randomly assigned into two groups receiving either acipimox (250 mg, twice daily) or placebo treatment. A total of 12 weeks later, these two groups switched their treatment for an additional 12 weeks. Blood samples were collected at the end of the run-in period and then at 4-week intervals in the whole study for lipid profile. A modified insulin suppression test was performed at the ends of the run-in period, 12-week and 24-week treatment to assess changes in insulin sensitivity. Our results showed that acipimox significantly lowered serum total triglyceride while compared to those by placebo. However, no difference was observed in serum non-esterified fatty acid, low-density lipoprotein cholesterol, total cholesterol (TC), high density lipoprotein-cholesterol (HDL-C) and HDL-C/ TC ratio between the two groups. Furthermore, glycemic indices and insulin sensitivity were similar during the base-line, placebo or acipimox periods. Taken together, our data suggest that acipimox significantly lowered TG without perturbation of insulin sensitivity in hypertriglyceridemic NIDDM patients.

Endothelin-1 induces insulin resistance in conscious rats

Since endothelin-1 (ET-1) might regulate insulin secretion and glucose metabolism, we carried out experiments to study the effect of ET-1 in conscious rats by injecting ET-1 (0.5 or 1.0 microgram/100 g body weight, i.p.) and examining the plasma glucose (PG) and insulin (PI) concentrations and PG/PI ratios continuously for 3 hours after the injection. Compared to the saline controls, ET-1 increased PG and PG/ P1 ratios in a dose-dependent manner. Oral glucose tolerance test (OGTT) performed at 30 min after the injection showed that PG levels stayed significantly higher in rats preinjected with ET-1 than rats with saline injection, although the change in PI levels was not different. Simultaneous infusion of glucose and insulin to somatostatin-primed rats with ET-1 or saline injection resulted in significantly higher steady state plasma glucose (SSPG) levels and SSPG/PI ratios in rats injected with ET-1 than control rats with saline. These results unequivocally indicated that intraperitoneally administered ET-1 induces insulin resistance in conscious rats.

Heterogeneous responses to the long-term treatment of active acromegaly with octreotide

To study GH response to the long-acting somatostatin analogue, we treated 11 actively acromegalic patients with octreotide (Sandostatin), 100 micrograms, sc, tid, for six months. Their endocrinological outcomes and clinical improvements varied. The 11-h GH secretory profiles on pretreatment day confirmed the hypersecretion of GH in all patients. Three hours after the first dose of octreotide, serum GH declined rapidly to levels below 5 ng/ml in all but two patients who failed to normalize their serum GH. In spite of the subsequent doses, there was no further suppression in serum GH. Drug resistance with GH rebound developed in some patients after three months of continued treatment. The paradoxical serum GH rises in response to oral glucose or iv TRH detected before the treatment in all patients attenuated or disappeared after the 6-month octreotide therapy; an exceptional case was one of the above-mentioned two patients, whose serum GH was stimulated more than before by glucose and TRH at the end of therapy. Serum insulin-like growth factor I (IGF-I) levels of all patients showed a significant reduction after 6-month treatment, but their mean values remained abnormally high. There were no intolerable adverse side effects; some patients, however, experienced pain at the injection site, passage of loose stool, and incidence of new gall stone or intrahepatic lesions on octreotide therapy. We concluded that octreotide was a useful long-term adjunctive therapeutic agent for patients with active acromegaly, but that a high degree of response heterogeneity including total refractoriness would be expected.

Lovastatin lowers serum cholesterol levels in non-insulin-dependent diabetes mellitus patients without altering their insulin sensitivity

BACKGROUND

Lovastatin, a potent 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, has been widely used in the treatment of hypercholesterolemia. It is also applied to dyslipidemia in patients with diabetes mellitus. The influence of lovastatin on insulin sensitivity was evaluated in twelve Chinese non-insulin-dependent diabetes mellitus (NIDDM) patients with hypercholesterolemia.

METHODS

This double-blind, randomized, placebo-controlled, and two-period cross-over experiment enrolled 12 patients. After a run-in period of two months, the patients were randomized into 2 groups to receive either lovastatin (20 mg once daily) or placebo treatment. Eight weeks later, two groups of patients exchanged their treatment for another 8 weeks. Blood samples were collected at the end of the run-in period and at 4-week intervals during the study to observe serum lipid profiles. A modified insulin suppression test was made to assess insulin sensitivity three times: at the end of run-in period, in week 8 and week 16, respectively. Wilcoxon signed rank test was used for analysis of statistical significance of the difference between lovastatin and placebo treatments.

RESULTS

As compared with the placebo, lovastatin reduced serum total cholesterol (TC) levels significantly. Serum total triglyceride (TG) concentrations decreased slightly by lovastatin. The ratio of TC to high density lipoprotein-cholesterol (HDL-C) also decreased significantly in lovastatin period. No difference was found in serum apolipoprotein A1 levels. A significant reduction of serum apolipoprotein B concentrations was also noted in lovastatin period. No difference in glycemic indices and insulin sensitivity was observed in the base-line, placebo or lovastatin periods.

CONCLUSIONS

The results demonstrated that lovastatin significantly lowered the serum TC levels without perturbation of insulin sensitivity in hypercholesterolemic NIDDM patients.

Endothelin-1 inhibits insulin-stimulated glucose uptake in isolated rat adipocytes

A single class of high affinity endothelin-1 (ET-1) binding sites with an apparent Kd of 350 pM and a binding capacity of 69,000 sites/cell was found in isolated rat adipocytes. Whereas ET-1 had no effect on basal glucose uptake, it inhibited insulin-stimulated glucose uptake in both a dose- and time-dependent manner. Insulin binding, however, was not altered. Thus, the present study demonstrates the presence of ET-1 receptor in isolated rat adipocytes and the inhibition of insulin-stimulated glucose uptake by ET-1 via a post-receptor mechanism.

Insulin-like growth factor-I receptor increases in aortic endothelial cells from diabetic rats

Endothelial cells are likely to play an important role in the development of diabetic vascular diseases, since they are exposed directly to the abnormal circulating metabolites of diabetes and may be easily damaged early in the natural course of vascular complications. In this study, aortic endothelial cells were cultured from diabetic BB rats. Their binding and internalization of insulin-like growth factor-I (IGF-I) were measured. IGF-I binding was higher in cells of diabetic rats than of control rats at both 37 degrees C (4.5% +/- 1.6% v 2.74% +/- 0.9% per mg protein, P < .05) and 4 degrees C (20.6% +/- 5.6% v 13.7% +/- 4.6% per mg protein, P < .01). Internalization of IGF-I also increased (1.62% +/- 0.2% v 0.74% +/- 0.15% of total count at 37 degrees C after 60 minutes, P < .05). Cross-linking studies showed that in cells from diabetic rats, the major band of 140 kd corresponding to the alpha-subunit of the IGF-I receptor increased in density by 50% compared with those from control rats. The IGF-I-stimulated tyrosine kinase activity (TKA) of partially purified receptor from cells of diabetic rats, measured using poly-glu-tyr as substrate, was normal. Since the biological effects of IGF-I are initiated by its binding to the IGF-I receptor, which is able to transduce mitogenic and metabolic signals, our results support the hypothesis that the IGF-I receptor is involved in the development of diabetic vascular complications.

Arginine induced insulin release in patients with newly onset non-insulin-dependent diabetes mellitus

To examine the release of insulin in response to oral glucose, intravenous glucagon and intravenous arginine, we measured the levels of plasma glucose, immuno-reactive insulin (IRI) and C-peptide levels on fasting and following an oral glucose loading (OGTT), intravenous glucagon (GON) and arginine (ARG) infusion test in nine newly diagnosed non-insulin dependent diabetics. Their ages ranged from 38 to 65. The fasting plasma glucose and hemoglobin A1c levels were 240 +/- 14 mg/dl (Mean +/- SEM) and 10.7 +/- 0.54%, respectively. Mean values of the peak C-peptide/fasting C-peptide ratio and peak IRI/fasting IRI ratio were significantly increased, as compared with the basal level (P < 0.05), but not significantly different from those of the OGTT, GON and ARG test. In conclusion, the effect of arginine-induced insulin secretion in non-insulin dependent diabetes mellitus is as good as those of glucose or glucagon.

Metabolic control and B cell function in patients with diabetes mellitus secondary to chronic pancreatitis

To investigate the relationship between metabolic control and beta cell functions in chronic pancreatitis, 30 patients were selected for study, including 10 with diabetes mellitus in insulin-dependent state (group 1, Mean age 37.6), 10 with diabetes mellitus in non-insulin-dependent state (group 2, Mean age 47.8), and 10 with normal fasting glucose levels (group 3, Mean age 42.1). Each patient received urine routine, stool fat, renal function, biochemical study such as: serum lipid and glycosylated hemoglobin, eye fundi and X-ray examinations. Beta cell function was measured by C-peptide concentration six minutes after intravenous infusion of 1 mg glucagon. The results showed that the glycosylated hemoglobin concentrations were higher in group 1 than in group 2 or 3 patients (P less than 0.05), and were higher in group 2 than in group 3 patients (P less than 0.001) as well. The cholesterol and triglyceride levels were not significantly different among three groups. Furthermore, eight and two of group 1 and 2 patients manifested pancreatic calcification on abdomen X-ray examination (P less than 0.05). All and eight of group 1 and 2 patients received insulin injection respectively. In addition, group 1 patients were more likely to develop steatorrhea, other associated diseases and uncontrolled plasma glucose levels as compared with group 2 patients. In conclusion, insulin-dependent pancreatic diabetics had more advanced disease process and were therefore more likely to get other associated diseases than noninsulin-dependent pancreatic diabetics.

Insulin-pen: preliminary report on its use for multiple injection regiment in insulin-dependent diabetic patients

Insulin pens are pen-like devices for multiple injection of insulin. They can cut down the equipment necessary for a multidose regimen and thus make the therapy more convenient and flexible to help improve daily-life quality. It is of interest for us to known whether the average diabetic patients are motivated to achieve better metabolic control by means of insulin-pens. Seven insulin-dependent diabetic patients (male: 3, female: 4, age: 21-34 years) from the Veterans General Hospital participated in the study. None of them had diabetic proliferative retinopathy or proteinuria. They are initially treated with twice daily injection of mixtures of short- and intermediate-acting insulin (run-in period, 8 weeks). A multi-dose regimen with three premeal injections of short-acting insulin with insulin-pen plus one injection of long-acting insulin at bedtime was then used during the study period (12 weeks). Improved in metabolic control as assessed by HbAlc (7.6 +/- 0.9 vs 6.9 +/- 0.8%) and mean blood glucose (175.2 +/- 34 vs 152.3 +/- 28.1 mg/dl) in all patients was found. The frequency and severity of hypoglycemic episodes were not changed. In addition, all patients chose to continue multiple injection using insulin-pen, indicating a high acceptability of such device.

A twelve month double-blind randomized study of the efficacy and immunogenicity of human and porcine insulins in non-insulin-dependent diabetics

This study aims to compare the effectiveness and immunogenicity of semisynthetic human insulin (NOVO) and highly purified (monocomponent) porcine insulin over a 12 month period in 16 non-insulin-dependent diabetic subjects not previously exposed to insulin. Sixteen patients were randomly allocated for treatment with either human (n = 9) or monocomponent porcine (n = 7) insulin in a double-blind trial. Both groups were identical with respect to age, sex and measures of metabolic control. Significant insulin antibody was detected in seven of the nine patients (78%) 3 months after the commencement of human insulin therapy whereas it was detected in all patients (100%) in the group treated with monocomponent porcine insulin as early as 2 months after insulin therapy. Besides the delayed rise of insulin antibodies during the first 3 months of human insulin therapy, it tended to have a lower mean insulin antibody titer, though statistically insignificant, at the end of the study. No adverse reaction to either type of insulins was noted. It is concluded that both semisynthetic human and monocomponent porcine insulin were safe and effective. Although human insulin showed a slightly lower immunogenicity than monocomponent porcine insulin of the same formulation and purities, it was not non-immunogenic. Hence, there is no reason to treat all insulin-requiring diabetic subjects with human insulin except those who have developed insulin allergy or those at risk or with a history of allergy.

Insulin treatment improved glucose-induced insulin release in elderly non-insulin-dependent diabetes mellitus, secondary failure to oral hypoglycemic agents

In order to observe whether the improvement of diabetic control would promote insulin release of elder non-insulin-dependent diabetics, we performed oral glucose tolerance test and glucagon infusion in eight patients before and after fasting plasma glucose normalized with insulin therapy for three weeks. The levels of plasma glucose and C-peptide both on fasting and following intravenous glucagon infusion and oral glucose loading were measured. Their ages ranged from 60 to 72 years old. The initial fasting plasma glucose levels were 261 +/- 18 mg/dl (Mean +/- SEM). After insulin therapy for three weeks, the fasting plasma glucose levels dropped to 130 +/- 8 mg/dl (Mean +/- SEM, P less than 0.001). The fasting C-peptide/glucose ratio showed no difference before and after therapy. On the other hand, the C-peptidogenic index was markedly improved following insulin therapy, as compared with the value before therapy (P less than 0.05). These results suggested that greater C-peptide response was found in non-insulin dependent elderly diabetics following oral glucose after plasma glucose normalized with insulin therapy.

Coexisting hyperthyroidism and hyperparathyroidism: two cases report

To examine the biochemical changes in coexisting hyperthyroidism and hyperparathyroidism, we have studied two female cases in our medical center. Both patients received biochemistry study, thyroid function test, thyroid autoantibody determination, parathyroid function tests and thyroid scan. They all had increased thyroid function. The concentration of parathyroid hormone was found to elevate in both cases. After thyroid function turned normal, hypercalcemia was still present. Both patients underwent neck operation. Parathyroid adenoma was found in both cases. The pictures of thyroid pathology showed diffuse hyperplasia in one case and lymphocytic thyroiditis in the other case.

Changes of insulin receptor in aortic endothelial cells from diabetic rats

Endothelial cells are likely to play an important role in the development of diabetic vascular diseases since they are exposed directly to the abnormal circulating metabolites of diabetes and may be easily damaged early in the natural course of vascular complications. Recently, we have demonstrated a decrease of insulin binding and autophosphorylation of the insulin receptor in cultured capillary endothelial cells of diabetic rats. In this study, similar defects in insulin receptor of aortic endothelial cells cultured from diabetic BB rats were found. The specific insulin binding was 45% lower in cells from diabetic than from non-diabetic rats (3.9 +/- 1.3 vs 7.3 +/- 1.2% per mg protein, p less than 0.05), which was due to a decrease of cell surface binding sites. In contrast to the decrease in insulin binding, insulin-like growth factor-I binding was higher in cells of diabetic than control rats (20.6 +/- 5.6 vs 13.7 +/- 4.6% per mg protein). The decrease in insulin binding could not be induced by the two-week treatment of endothelial cells from non-diabetic rats with medium containing high concentration of glucose (400 mg/dl). Insulin-induced tyrosine kinase activity of partially purified insulin receptor measured using poly-glutyr as substrate was also lower in cells from diabetic rats (normal:1.4 +/- 0.6-fold; diabetic 0.5 +/- 0.3-fold above baseline; (p less than 0.05). These data suggest that the diabetic milieu in vivo can induce persistent defects in insulin receptor of aortic endothelial cells. Further studies are warranted to understand the potential pathophysiological role of these defects.

Thyrotropin-and prolactin--secreting pituitary tumor dissociated hormonal response to bromocriptine

A 41-year-old male with recurrent hyperthyroidism resulting from pituitary tumor was studied. Because of recurrent hyperthyroidism, he had been treated with propylthiouracil for four years and had been operated. At the time of high serum thyroid hormone (T4: 20 micrograms/dl; T3:502 ng/dl), there was also elevated basal serum TSH level (55 microU/ml) which could not be suppressed by exogenous thyroid hormone administration. In addition, the serum TSH showed blunt response to intravenous TRH infusion. An elevated serum prolactin level was also observed (111 ng/ml). After bromocriptine administration (2.5 mg daily), the suppressibility of serum TSH level was found better than that of prolactin level. The existence of a TSH- and PRL-secreting pituitary tumor in this patient exhibited a dissociated hormonal response to low doses of dopaminergic agents.

Intractable diabetic ketoacidosis due to insulin antibody--response to steroid therapy

To examine the effect of steroid therapy on insulin antibody titer in insulin-dependent diabetes mellitus, we studied a 58 year-old gentleman with recurrent diabetic ketoacidosis. No any overt precipitating factors could be accounted for, except limited pancreatic beta cell reserve and high titers of anti insulin antibodies. Despite the persistence of high titers of plasma antiinsulin antibodies, the clinical manifestations of diabetic ketoacidosis improved greatly by the administration of steroid. Nevertheless, the patient still showed the great excursion of plasma glucose concentration.

Immunogenicity of highly purified porcine and human insulins in diabetic patients with high titers of insulin antibody

Twenty-nine non-insulin-dependent diabetic Chinese subjects previously treated with conventional porcine isophane insulin (NPH) for a period of time, whose titer of serum insulin antibody was greater than 40% were changed to either highly purified pork insulin (Nordisk, Denmark) or human insulin of recombinant DNA origin (Eli Lilly, USA) for 1 year in a double-blind and randomized trial. The human (n = 16) and pork insulin (n = 13) groups were carefully matched for age, sex and measures of metabolic control. In highly purified pork-insulin-treated patients, the glycated hemoglobin and fasting blood sugar values began to fall significantly from a mean of 13.2% to 12.3% (p less than 0.05) and 228 mg/dl to 183 mg/dl (p less than 0.005), respectively, 2 months after the commencement of this study, whereas insulin antibody levels began to fall significantly from a mean of 61.8% to 49.5% (p less than 0.01) 6 months after the start of the study. Also, daily insulin doses increased significantly from a mean of 58 units to 70 units (p less than 0.005) 6 months after the start of the study. In human-insulin-treated patients, there were no significant changes in the glycated hemoglobin values. The fasting blood sugar levels fell significantly (p = 0.0515) at the end of the study period but the insulin antibody levels did not show any significant change during the same study period. Daily insulin dose increased significantly from a mean of 51 units to 57 units (p less than 0.01) 4 months after beginning the study.(ABSTRACT TRUNCATED AT 250 WORDS)

The establishment of a radioimmunoassay of calcitonin in human serum

A sensitive sequential radioimmunoassay of calcitonin (CT) is described. Synthetic human CT was used for 125I-labelling and for preparation of anti-sera. The labelled hormone was purified by QUSO and P10 column. The specific activity of the purified 125I-CT was 39.8 Ci/g. The anti-sera was produced by immunization of guinea pigs with human synthetic CT which was conjugated with carbodiimide onto BSA (bovine serum albumin). Separation of free from antibody bound 125I-labelled CT was performed using DCC precipitation. Standard curves of extracted plasma, extracted plasma plus human CT were parallel to the standard curve. Recovery of 62.5 to 500 pg/ml CT were in the range of 80.72 to 113.4%. The Scatchart plot of the binding data showed a straight line with a kd of 56 pM and Bmax of 35 pM. The specificity of the antiserum was good. The lower limit of detection was 31.25 pg/ml. Our results indicate that this assay system may be useful in both clinical use and research.

Identification of persistent defects in insulin receptor structure and function capillary endothelial cells from diabetic rats

Insulin actions and receptors were studied in capillary endothelial cells cultured from diabetic BB rats and their nondiabetic colony mates. The endothelial cells from diabetic rats of 2 mo duration had persistent biological and biochemical defects in culture. Compared with normal rats, endothelial cells from diabetic rats grew 44% more slowly. Binding studies of insulin and insulin-like growth factor I (IGF-I) showed that cells from diabetic rats had 50% decrease of insulin receptor binding (nondiabetic: 4.6 +/- 0.7; diabetic: 2.6 +/- 0.4% per milligram protein, P less than 0.01), which was caused by a 50% decrease in the number of binding sites per milligram protein, whereas IGF-I binding was not changed. Insulin stimulation of 2-deoxy-glucose uptake and alpha-aminoisobutyric acid uptake were also severely impaired with a 80-90% decrease in maximal stimulation, in parallel with a 62% decrease in insulin-stimulated autophosphorylation (P less than 0.05). 125I-insulin cross-linking revealed an 140-kD alpha subunit of the insulin receptor similar to that in cells from nondiabetic rats, although bands at greater than 200 kD were also detected. The molecular weight of the insulin receptor beta subunit (by SDS-PAGE) was smaller in cells from diabetic than from normal rats (88-90 vs. 95 kD). Neuraminadase treatment of the partially purified insulin receptors decreased the molecular weight of the insulin receptors from nondiabetic rats to a greater degree than its diabetic counterpart. In contrast, Northern blot analysis of insulin receptor mRNAs using human cDNA probes revealed two species of 9.4 and 7.2 kb with no difference in mRNA abundance between cells from diabetic and nondiabetic rats. We conclude that the exposure of capillary endothelial cells to a diabetic milieu in vivo can cause specific and persistent changes in the insulin receptor and insulin action.

The antilipemic effectiveness of pentaerythritol tetranicotinate on hyperlipidemic patients with or without diabetes mellitus--a double-blind, randomized and two-period change-over experiment

Pentaerythritol tetranicotinate (Perycit), at an oral dosage of 750 mg daily, was given to 12 patients with idiopathic hyperlipidemia and to 12 patients with hyperlipidemia superimposed with diabetes mellitus (DM). With 2 months off-drug period as the baseline, each patient then received 3 months of placebo and 3 months of Perycit. The sequence of treatment was randomized and balanced in frequency. Blood glycosylated hemoglobin (Hb A1) and fasting plasma glucose (FPG) were used as indices of diabetic control. Serum triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), and TC/HDL-C ratio were measured and calculated in order to compare the antilipemic effectiveness of Perycit with that of placebo. The non-parametric Wilcoxon test was used for the statistical analysis. The results showed that in the idiopathic group, Perycit significantly lowered the serum level of TG and the ratio of TC/HDL-C, and elevated the serum level of HDL-C. In the diabetic group, although there was a similar improvement in diabetic control in both periods of placebo and Perycit treatments, there was no change in the serum levels of TG and HDL-C. There was a slight increase of the serum levels of TC in the periods of Perycit treatment, whereas a small increase of HDL-C resulted in a mild decrease of the TC/HDL-C ratio. There was mild and transient facial flushing during the Perycit treatment in 6 out of 12 diabetic patients. Otherwise, there was no side effects in either group. Pooling the two groups' data together, Perycit increased the serum levels of HDL-C and decreased the TC/HDL-C ratio. It is concluded that Perycit has antilipemic effects in patients with idiopathic hyperlipidemia, and may be helpful in reducing the atherogenic risks in these patients. In patients with hyperlipidemia superimposed with DM, although the serum lipids composition was not significantly changed after Perycit, the atherogenic risks might also be reduced as demonstrated by the decrease of the TC/HDL-C ratio.

A therapeutic trial of bezafibrate on patients with hyperlipidemia with or without diabetes mellitus

Bezalip (bezafibrate), at an oral dosage of 200 mg three times a day, has been used on 12 patients with idiopathic hyperlipidemia, and on 12 patients with hyperlipidemia superimposed with diabetes mellitus. Each patient received bezafibrate for 3 months and placebo for 3 months. Blood glycosylated hemoglobin (HbA1) and fasting plasma glucose (FPG) were used as indices of diabetic control. Serum triglyceride (TG), total cholesterol (TC), high density lipoprotein-cholesterol (HDL-C), and TC/HDL-C ratio were measured and calculated in order to compare the antilipemic effects of bezafibrate with that of placebo. Non-parametric Wilcoxon test was used for statistical analysis. In both the idiopathic group and diabetic group, bezafibrate significantly lowered the serum levels of TG and TC/HDL-C, as well as elevated the level of HDL-C. The serum TC levels were not significantly altered in either of the groups. These effects could not be ascribed to an improved diabetic control, since the percent changes of HbA1 were not different between the bezafibrate periods and the placebo periods. There were no significant facial flushing, nor other side effects during the treatment with bezafibrate. It is concluded that bezafibrate has antilipemic effects, and may be helpful in reducing the atherogenic risks.