In SilicoStructure-Based Design of a Potent and Selective Small Peptide Inhibitor of Protein Tyrosine Phosphatase 1B, A Novel Therapeutic Target for Obesity and Type 2 Diabetes Mellitus: A Computer Modeling Approach

Protein Tyrosine Phosphatase 1B (PTP1B) has been shown to be a negative regulator of insulin signaling by dephosphorylating key tyrosine residues within the regulatory domain of the beta-subunit of the insulin receptor. Recent gene knockout studies in mice have shown the mice to have increased insulin sensitivity and improved glucose tolerance. Furthermore, these mice also exhibited a resistance to diet induced obesity. Inhibitors of PTP1B would have the potential of enhancing insulin action by prolonging the phosphorylated state of the insulin receptor. In addition, recent clinical studies have shown that the haplotype ACTTCAG0 of the PTPN1 gene, which encodes PTP1B, is a major risk contributor to type 2 diabetes mellitus (T2DM). Thus, there is compelling evidence that small molecule inhibitors of PTP1B may be effective in treating insulin resistance at an early stage, thereby leading to a prevention strategy for T2DM and obesity. Based on the crystal structure of the complex of PTP1B with a known inhibitor, we have identified a tetrapeptide inhibitor with the sequence WKPD. Docking calculations indicate that this peptide is as potent as the existing inhibitors. Moreover, the peptide is also found to be selective for PTP1B with a greatly reduced potency against other biologically important protein tyrosine phosphatases such as PTP-LAR, Calcineurin, and the highly homologous T-Cell Protein Tyrosine Phosphatase (TCPTP). Thus the designed tetrapeptide is a suitable lead compound for the development of new drugs against type 2 diabetes and obesity.

High-dose vitamin E supplementation does not diminish ribavirin-associated haemolysis in hepatitis C treatment with combination standard alpha-interferon and ribavirin

BACKGROUND

Ribavirin is associated with haemolytic anaemia. Antioxidants have been reported to decrease severity of this anaemia.

AIM

To determine effect of vitamin E supplementation on ribavirin-associated haemolysis in chronic hepatitis C treated with standard alpha-interferon and ribavirin.

METHODS

Fifty-one naive chronic hepatitis C patients were randomized to receive either alpha-interferon/ribavirin therapy (control) or therapy plus vitamin E 800 IU b.d. with 24-week follow-up. Alanine aminotransferase ALT, haemoglobin and reticulocyte percentage were monitored. Symptoms and health-related quality of life were also monitored at each visit.

RESULTS

Forty-seven subjects were treated (27 vitamin E /20 controls). Thirteen withdrew because of adverse effects or non-compliance. Groups were similar in demographics, genotype and baseline lab indices. Comparison with baseline, treatment and follow-up values showed a significant haemoglobin and ALT reduction in both groups. There was no significant difference in haemoglobin and reticulocyte percentage between groups. Sustained viral response was not significantly different between vitamin E (11/18) and control (6/16) groups. Three patients required ribavirin dose-reduction in the vitamin E group compared with two controls. Health-related quality of life during and end-of-treatment was not different between groups.

CONCLUSIONS

Vitamin E supplementation alone during standard alpha-interferon and ribavirin therapy does not appear to diminish ribavirin-associated haemolysis.

Coagulation profile and platelet function in patients with extrahepatic portal vein obstruction and non-cirrhotic portal fibrosis

BACKGROUND AND AIMS

Coagulation disorders commonly develop in patients with cirrhosis of the liver. They have also been reported in patients with non-cirrhotic portal fibrosis (NCPF) and extra-hepatic portal venous obstruction (EHPVO); the two conditions with portal hypertension and near-normal liver functions. The spectrum and prevalence of coagulation abnormalities and their association with the pathogenesis of these diseases and with hypersplenism was prospectively studied.

METHODS

Eighteen EHPVO patients that included an equal number of NCPF patients and 20 healthy controls were prospectively studied. The coagulation parameters assessed included: international normalized ratio, partial thromboplastin time, and fibrinogen and fibrinogen degradation products. Platelet aggregation and malondialdehyde levels were measured.

RESULTS

Both EHPVO (83%) and NCPF (78%) patients had a significantly prolonged international normalized ratio and a decrease in fibrinogen and platelet aggregation. The EHPVO patients had a significant prolongation in partial thromboplastin time (67% patients), with increased levels of fibrinogen degradation product levels occurring in all patients; these were normal in NCPF patients. Platelet malondialdehyde levels were normal in both groups. Hypersplenism was present in four EHPVO and seven NCPF patients. It did not significantly influence the coagulation profile in either NCPF or EHPVO patients.

CONCLUSIONS

Coagulation anomalies are common and significant in both NCPF and EHPVO patients, suggestive of a mild disseminated intravascular coagulation disorder. These imbalances could be caused by chronic subclinical endotoxemia and cytokine activation after the initial portal thromboembolic event. The persistence of these abnormalities in adolescent patients indicates an ongoing coagulation derangement.

Synergistic immunosuppression by candida in HIV infection: a cytokine based analysis

Candida is a common opportunistic pathogen in HIV infection and is regarded a signal infection for progression to AIDS. Cytokine imbalances between Th1/Th2 groups have been described in both candida and HIV infections. A study was undertaken to assess the role of candida in furthering immunosuppression in HIV infection based on cytokine levels and CD4 cell counts. 30 Indian subjects were enrolled; 10 HIV positive patients with and 10 without mucosal candidiasis and 10 age matched controls. Th1 cytokines; interleukin (IL) 2, IL 12 and interferon (IFN) gamma, Th2 cytokines; IL 4, IL 6, IL 10 and tumor necrosis factor (TNF) alpha with CD 4 cell counts were estimated using ELISA in all subjects. CD4 cell counts were reduced in both patient groups as compared to controls; significantly more in patients with both HIV and candida infections. There was a decrease in Th1 cytokine levels in all patients; lower levels of Th1 cytokines were seen in patients with both infections. Among the Th2 cytokines, there was a significant increase in the levels of IL 6, IL 10 and TNF alpha in both patient groups; IL 10 and TNF alpha values were significantly raised in patients with dual HIV and candida infections as compared to the other patients. There was no difference in IL 4 values across the subject groups. A positive correlation between CD4 cell counts and Th1 cytokine levels and a negative correlation with Th2 cytokines were noted; these were stronger in patients with both HIV and candidiasis. Thus, there was a Th1/Th2 cytokine imbalance with CD4 cell count reduction in all HIV infected patients, which was more pronounced in patients with both infections. It can be concluded that, owing to the depressed CD4 cell count and Th1 response and increased Th2 cytokines in patients with both candidiasis and HIV as compared to patients with only HIV candidiasis may have a synergistic immunosuppressive effect with HIV in patients with dual infections.

Effects of long-term use of testosterone enanthate. II. Effects on lipids, high and low density lipoprotein cholesterol and liver function parameters

The present study was designed to evaluate the effects of long-term administration of testosterone enanthate (TE) on lipid and liver function parameters in rhesus monkeys (n = 9) maintained under controlled dietary conditions. Bimonthly administration of 50 mg of TE increased serum testosterone into the supraphysiological range one day after injection and peak levels were seen on day 3, followed by a decrease to above baseline values by day 14. High density lipoprotein cholesterol (HDL-C) levels decreased gradually; compared to baseline values, the decline was significant from the 19th month of injection until the first month of recovery. The increase in low density lipoprotein cholesterol (LDL-C) levels and the LDL-C/HDL-C ratio during the treatment period was not significant compared to baseline values; however, when compared to control animals, HDL-C and LDL-C levels and the LDL-C/HDL-C ratio were significantly elevated from the 12th month until the end of the treatment period. All lipid parameters recovered by the end of the treatment period. Control animals (n = 9) did not show significant changes in HDL-C and LDL-C levels and the LDL-C/HDL-C ratio during the study period. Total cholesterol levels decreased in control (n = 9) and treated animals from 6 to 15th months of the treatment period, coinciding with the feeding of sprouted grams to animals. TE injections did not change the levels of triglycerides, alkaline phosphatase or bilirubin in control and treated animals. However, transaminase (SGOT and SGPT) levels increased following TE injections and remained elevated until the end of injections followed by a return to baseline values or below during the recovery period. These effects could be due to the pharmacokinetic profile of TE in which testosterone levels were elevated to supraphysiological values after injections. The recovery of the TE-induced changes in lipid parameters and liver transminases is reassuring but the changes in these parameters during TE injections indicate the need for long-acting androgens with better pharmacokinetic properties.

Correlation of acetylator phenotype with peripheral, autonomic and central neuropathy in Northern Indian non-insulin-dependent diabetes mellitus patients

OBJECTIVES

Genetic susceptibility to diabetic neuropathy has been suspected and tentatively explored; however, diabetic autonomic and central neuropathies are poorly investigated areas. Previous trials correlating types of diabetes and diabetic neuropathy with acetylator dimorphisms have not been conclusive. The present study was designed to test peripheral neuropathy, autonomic neuropathy and integrity of central conduction pathways in patients of non-insulin-dependent diabetes mellitus (NIDDM), and to correlate the findings with the acetylator phenotype.

METHODS

Twenty-six patients of NIDDM with stable glycaemic control and 11 age- and sex-matched control subjects were recruited, clinically examined and investigated with glycaemic and lipid profile, renal function tests, nerve conduction studies (sensory and motor), auditory brain stem evoked responses (ABERs) and somatosensory evoked potentials (SEPs). Acetylator status of the subjects was determined by sulphadimidine test.

RESULTS

Out of 26 NIDDM patients, eight (30.7%; group 1A) were slow acetylators and 18 (69.3%; group 1B) were fast acetylators. The distribution of slow and rapid acetylators in both the groups was similar. Glycaemic and lipid profiles and 24-h urinary albumin excretion in groups 1A and 1B were also similar. Motor nerve conduction velocity, latency of F wave, sensory nerve conduction and amplitudes of sensory nerve action potentials were not different between fast and slow acetylator NIDDM patients. On testing for ABERs, there were no statistically significant differences in peak latencies of waves I, III and V; interpeak latencies (IPLs) I-III, III-V and I-V; amplitude of waves I, III and V on both sides between NIDDM patients and controls. However, peak latencies of wave III (P < 0.01), wave V (P < 0.005), IPLs I-III and I-V (P < 0.005), IPLs III-V (P < 0.05), and amplitudes of wave I (P < 0.05) and wave V (P < 0.05) on the left side were significantly different in slow acetylator NIDDM patients. Increase on the right side for the same group was statistically significant for IPLs I-III and I-V (P < 0.05). SEPs showed no statistically significant difference between NIDDM patients and controls, and slow and fast acetylator NIDDM patients.

CONCLUSIONS

No significant association of acetylator status with peripheral neuropathy in NIDDM subjects was observed in the present study. However, central neural conduction, primarily tested by ABERs, was significantly delayed in slow acetylators compared with fast acetylator NIDDM patients. Hence, there may be a predisposition to neuropathy in this group of patients, and such a predisposition may be better detected by studying central rather than peripheral nervous conduction pathways in NIDDM patients.

Effects of long-term treatment with testosterone enanthate in rhesus monkeys: I. Pharmacokinetics of testosterone, testicular volume and liver metabolism of testosterone

The effects of long-term administration of testosterone enanthate on the pharmacokinetics and bioavailability of testosterone were studied in adult male rhesus monkeys (n = 9), injected with 50 mg of testosterone enanthate (TE) once every 14 days for a total of 32 months. Control animals were injected with 0.2 mL olive oil. Serum testosterone levels increased sharply within 24 h of the first injection of TE and reached a peak on day 3 followed by a sharp decline, but baseline values were not reached even by day 14. Subsequent injections of TE caused a similar pharmacokinetic profile until the 55th injection; testosterone levels on day 3 declined from the 56 to 58th injection and remained in a lower range until the last injection. Repeated injections of TE increased the bioavailability of testosterone as shown by the Area Under the Curve. The nocturnal (22.00 h) surge in testosterone levels during the pretreatment phase was abolished by TE injections. TE injections altered the metabolism of testosterone by the liver, as studied in vitro; while liver from control animals converted testosterone to androstenedione as the major metabolite, androsterone was the major metabolite in chronically TE-treated animals. Spermatogenesis and the associated increase in testicular volume observed in control animals in winter were suppressed in TE-treated animals. The results indicate that repeated TE injections elevate serum testosterone to supra-physiological levels with marked fluctuations in circulating testosterone levels after each injection. Possibly in response to these elevated levels, there was a change in the metabolism of testosterone by the liver as observed in vitro.

Clustering of impaired glucose tolerance, hyperinsulinemia and dyslipidemia in young north Indian patients with coronary heart disease: a preliminary case-control study

Metabolic insulin resistance syndrome is a critical factor in the pathogenesis of atherosclerosis and coronary heart disease in Indians. In a preliminary case-control study, 44 young patients (age < 40 years) with coronary heart disease (angina, myocardial infarction), not previously diagnosed to have diabetes mellitus, were recruited seven days to six weeks after the cardiac event (group I), and compared to 20 healthy subjects (group II). After recording history and anthropometric data, they were subjected to oral glucose tolerance test. Each group was divided into A and B subgroups according to the magnitude of impaired glucose tolerance. Hypertension was recorded in 11 (25%) patients in group I, while all the subjects in group II were normotensive (p < 0.05). Groups IB and IIB, consisting of subjects with impaired glucose tolerance displayed significantly high post-load blood glucose values. After excluding patients with the family history of diabetes mellitus, there were 13 (39%) and 3 (17%) patients with impaired glucose tolerance in groups I and II, respectively. Total cholesterol and low-density lipoprotein cholesterol levels were higher in group I as compared to group II (p < 0.01). Group IB showed highest mean values of total cholesterol, triglycerides, low-density lipoprotein cholesterol and lowest level of high-density lipoprotein cholesterol as compared to other subgroups. Serum insulin levels at 30 and 90 minutes were significantly higher in group I (p < 0.05). Group IB and IIB showed higher insulin values at 90 minutes when compared to group IA (p < 0.05) and IIA (p < 0.05). Elevated serum insulin values at 90 minutes during oral glucose tolerance test could differentiate among both groups and subgroups, except IB versus IIB. The study demonstrates significantly high prevalence of hypertension, obesity, impaired glucose tolerance, hyperinsulinemia and dyslipidemia, suggesting fully developed metabolic insulin resistance syndrome in young north Indian patients with manifest coronary heart disease.

Effects of long-term administration of testosterone enanthate on glucose metabolism in rhesus monkeys

The effects of long term administration of testosterone enanthate (TE) on glucose metabolism including glucose tolerance test (GTT) and fasting serum insulin levels were evaluated in adult rhesus monkeys kept under controlled dietary conditions. Adult male rhesus monkeys (n = 9) were administered 50 mg of TE bimonthly for 32 months, whereas control animals were injected the vehicle only. Glucose concentration reached a maximum 5 min after an intravenous glucose load and thereafter decreased gradually to reach near baseline values within 60 min. Significant changes in GTT or t1/2 of glucose were not seen in animals treated with TE, throughout the treatment period. However, serum insulin levels decreased significantly from months 27-32 of TE treatment and returned to baseline values within 3 months of recovery.

Changes in structure and functions of prostate by long-term administration of an androgen, testosterone enanthate, in rhesus monkey (Macaca mulatta)

The increasing use of androgens in clinical trials for developing a safe, effective, and reversible male contraceptive has necessitated a critical evaluation of the effects of their long-term use on the structure and functions of the prostate gland, which is androgen dependent. Combination regimens using progestogens, gonadotropin-releasing hormone antagonists, or antiandrogens along with androgens are undergoing clinical evaluation as antispermatogenic agents. The majority of these regimens have used testosterone enanthate (TE) as the androgen of choice, but very limited information is available on the side effects of long-term androgen use. The present study is the first report that critically evaluates the effects of long-term use of TE on prostate structure and functions. Adult male rhesus monkeys received intramuscular injections of 50 mg of TE once in 14 days for 33 months. The cranial and caudal lobes of the prostate, which were removed under ketamine anesthesia, were processed for the preparation of semithin sections to evaluate histological changes. The DNA distribution in the cells was studied in single cell suspensions of cranial and caudal lobes of the prostate by using flow cytometry. Changes in the levels of testosterone, estradiol, prostate-specific acid phosphatase (PAP), and prostate-specific antigen (PSA) in samples collected during the pretreatment period and at the time of removal of the prostate were estimated by using conventional procedures. Control samples were processed simultaneously. The administration of TE for 33 months caused the following changes: 1) significant increase in the weight of both lobes of the prostate, 2) cellular hypertrophy and increase in secretory material in the cells and in the lumen of the acini in the central and peripheral zones of the two lobes of the prostate, 3) cellular hyperplasia indicated by flow cytometric analysis of DNA content, 4) significant increase in the secretion of PAP and levels of estradiol, and 5) a marked increase in fibromuscular stroma in the central and peripheral zones of both the lobes of the prostate. The present study is the first report to provide evidence that long-term androgen treatment has caused hypertrophy of the prostatic epithelial cells, which showed increased secretory activity. The hyperplastic changes indicate a need for the development of new androgens with a better pharmacokinetic profile for use in male contraceptive regimens.

Hyperinsulinemia and dyslipidemia in non-obese, normotensive offspring of hypertensive parents in northern India

Insulin resistance contributes to initiation and acceleration of hypertension and atherosclerosis. This study attempted to detect occurrence of pre-hypertensive metabolic abnormalities, including hyperinsulinemia, in the offspring of hypertensive patients. Thirty-eight healthy offspring of hypertensive parents (group I, mean age 23.6+/-3.7 years) and 18 control offspring of normotensive parents (group II, mean age 24.2+/-2.8 years) were clinically examined, subjected to oral glucose tolerance test (OGTT), and the samples were analysed for blood glucose, insulin and lipid profile. Subjects in group I with fasting serum insulin <90 nmol/L constituted group Ia (n = 23, 62%) and those with >90 nmol/L constituted group Ib (n = 15, 38%). Both groups consisted of non-obese and normotensive subjects matched for body mass index and waist-hip ratio. There were no statistically significant differences in blood glucose levels between groups Ia, Ib and II during OGTT. Serum insulin levels during OGTT in group I were significantly higher than in group II (p<0.05), except at 30 min. Fasting insulin and 2 h post-OGTT insulin in group Ib were significantly higher than the other groups. Serum triglyceride levels, though within normal range, were higher in group I than group II (p<0.01). Similarly, high-density lipoprotein cholesterol levels in groups Ia and Ib were lower than those observed in group II (p<0.01). In conclusion, non-obese, normotensive offspring of hypertensive parents were observed to be hyperinsulinemic and dyslipidemic at an early age. These metabolic abnormalities may be associated with hypertension, glucose intolerance and accelerated atherosclerosis in adulthood.

Suppression of testicular and epididymal functions in a non-human primate (bonnet monkey) by combined administration of a gonadotropin-releasing hormone antagonist and testosterone buciclate

The ability of a long-acting androgen, testosterone buciclate (TB), to induce suppression of testicular and epididymal sperm functions when given in combination with a potent GnRH antagonist (Antide) either on day 1 or 45 of Antide administration (days 1-90) as well as the ability of TB to maintain Antide-induced suppression of spermatogenesis were evaluated in adult bonnet monkeys. A group of untreated animals (group I) acted as controls. All animals given Antide and androgen simultaneously (group II) became azoospermic but at different times. When androgen administration was delayed 45 days after start of Antide treatment (group III), the mean sperm concentration remained in the normospermic range and only three animals became azoospermic. Antide given alone (group IV) induced azoospermia in three animals and oligospermia in the remaining animals; spermatogenesis recovered when Antide was withdrawn and TB was injected. In all Antide-treated animals (groups II-IV), non-motile spermatozoa or sperm with non-progressive motility and poor gel penetrability were seen in the ejaculate.

Pattern of non-insulin dependent diabetes mellitus in Kuwait

The aim of this study was to examine distinctive clinical characteristics of non-insulin dependent diabetes mellitus (NIDDM) patients in Kuwait including mode of presentation at diagnosis, family history of diabetes, therapeutic management and response to treatment. We studied 3299 Kuwaiti patients (1454 male (M) and 1845 female (F) subjects) registered in Salmiya diabetic clinic, a part of the national network of diabetes control and care programme, and located in the urban Hawally Governorate, Kuwait. The mean age of the patients was 53 years (+/- 13.9 years), and 73.8% were in the age group 45-64 years. The majority of patients (53.6%) were diagnosed as they were clinically symptomatic; in contrast a significant minority (37.8%) were diagnosed by chance mainly during investigation for unrelated events. The 8.6% of the women diagnosed during pregnancy had a high parity index 6.5 +/- 2.9. A high percentage of the diabetic patients (63%) reported a positive family history in first degree relatives. The mean duration of diabetes mellitus was 7.8 years (range 2-28 years) and 70% of the patients had diabetes mellitus for 9 years or less. The mean body mass index (BMI) was 31.8 +/- 6.3 kg/m2 and 28.5 +/- 6.3 kg/m2 in women and men, respectively. Among the diabetic women 57.7% were obese (BM > 30 kg/m2) and 30.2% were overweight (BMI 25-30 kg/m2) as compared to 33.6% and 44.3% among diabetic men, respectively. High blood pressure (> or = 160/95 mmHg) was reported in 14.9%. The main therapeutic modality in the majority of patients, (63.2%), was the administration of oral hypoglycaemic agents (OHA), while 23.7% were on a diet regimen and only 13.1% were on insulin therapy. The study throws light on the pattern of NIDDM among Kuwaiti patients. Frequent association with obesity suggests that it may be a major risk factor. The strong familial aggregation reported paves the way for future research among these families for cosegregation of a defined genetic trait with NIDDM in the Arab population subset.

Effects of testosterone buciclate on testicular and epididymal sperm functions in bonnet monkeys (Macaca radiata)

The effects of testosterone buciclate (TB), a long-acting androgen ester given i.m. at four sites (20 mg/site) on days 1 and 91 of the study period (360 days), on reproductive and hormonal parameters were evaluated in five adult male bonnet monkeys; untreated animals (n = 5) acted as controls to monitor seasonal changes in these parameters. In control animals, testicular volume remained unchanged throughout the study; sperm count, motility and gel penetrability decreased while the percentage of spermatozoa showing retention of cytoplasmic droplet and coiled tail increased in June-July (days 210-240), preceded by reduction in serum testosterone (T) levels on days 120-150 (March-April). The TB-treated animals showed reduced testicular volume (days 90-270), suppressed sperm motility and gel penetrability (days 45-240 except on day 120), decreased sperm count (days 75-270), and an increased percentage of spermatozoa showing retention of cytoplasmic droplet and coiled tail (days 45-240 except on day 120). Even though serum T levels remained elevated until day 300, these levels were within the physiological range. The changes induced by TB were reversible. The suppression of testicular and epididymal functions by TB indicates that this long-acting androgen may have the potentiality to induce and maintain reversible sterility, but further evaluation needs to be carried out to develop an appropriate dosage regimen that would prevent return to normal functions in order to develop this long-acting androgen as a hormonal male contraceptive.(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolic factors in the development of retinopathy of juvenile-onset type I diabetes mellitus

Thirty-five patients of insulin-dependent diabetes mellitus (IDDM) were investigated for the effect of various metabolic factors on retinopathy. The severity of retinopathy increased with duration and age of onset of IDDM. Degree of glycaemia (fasting blood sugar, FBS) was similar in patients with or without retinopathy. All IDDM patients as a group showed severe carbohydrate intolerance with lower basal and post glucose serum immunoreactive insulin (IRI) levels and serum C-peptide radioimmunoreactivity (CPR) as compared to controls. The insulin secretory response was similar in no retinopathy, mild retinopathy and severe retinopathy groups. Patients with retinopathy had higher incidence of hyperlipidemia but mean serum levels of cholesterol and triglyceride were similar. This study does not suggest a direct relationship between the various metabolic factors studied and retinopathy due to IDDM.

Environmental release of chemicals and reproductive ecology

Reproductive ecology is defined as "the study of causes and mechanisms of the effects of environmental risk factors on reproductive health and the methods of their prevention and management." Major areas of concern, within the purview of this paper, relate to adverse pregnancy outcomes, effects on target tissues in the male and the female, and alterations in the control and regulatory mechanisms of reproductive processes. Teratogenic potential of chemicals, released as a result of accidents and catastrophes, is of critical significance. Congenital Minamata disease is due to transplacental fetal toxicity caused by accidental ingestion of methyl mercury. Generalized disorders of ectodermal tissue following prenatal exposure to polychlorinated biphenyls have been reported in Taiwan and Japan. The Bhopal gas disaster, a catastrophic industrial accident, was due to a leak of toxic gas, methyl isocyanate (MIC), in the pesticide manufacturing process. The outcome of pregnancy was studied in female survivors of MIC exposure. The spontaneous abortion rate was nearly four times more common in the affected areas as compared to the control area (24.2% versus 5.6%; p < 0.0001). Furthermore, while stillbirth rate was found to be similar in the affected and control areas, the perinatal and neonatal mortality rates were observed to be higher in the affected area. The rate of congenital malformations in the affected and control areas did not show any significant difference. Chromosomal aberrations and sister chromatid exchange (SCE) frequencies were investigated in human survivors of exposure. The observed SCE frequencies in control and exposed groups indicated that mutagenesis has been induced. Strategies for the management, prediction, and preventability of such disasters are outlined.

Apolipoprotein A-I, A-II, B, C-II, and C-III in children with insulin-dependent diabetes mellitus

This study was conducted to determine whether changes in the levels of plasma apolipoproteins (apo) A-I, A-II, B, C-II, and C-III, along with cholesterol and triglycerides, could provide additional information on these parameters in relation to the control of glycemia. Plasma and lipoprotein lipids and apolipoprotein levels were measured in 123 insulin-dependent diabetic children (4- to 12-years-old), classified into good, fair, and poor diabetic control based on HbA1c and fructosamine levels, and in 62 comparable healthy controls. Total cholesterol, very low density lipoprotein cholesterol, and low density lipoprotein cholesterol, as well as total triglycerides, very low density lipoprotein, low density lipoprotein, and high density lipoprotein (HDL) triglycerides, and apo B and apo C-III were increased significantly in children with fair and poor diabetic control. While in diabetic children with good control, only very low density lipoprotein cholesterol was elevated significantly compared with healthy control subjects. Conversely, the levels of cholesterol in HDL, HDL2, HDL3, and apo A-I were decreased significantly in the three diabetic groups, but apo A-II and apo C-II did not change. We conclude that in children with insulin-dependent diabetes mellitus, abnormalities in plasma lipid, lipoprotein, and apolipoprotein levels occur, the extent of which depends on the degree (extent) of glycemic control (the poorer the control the more substantial the abnormality). We suggest that measurement of apo C-III level along with apo B and apo A-I in these patients may be a sensitive indicator to alterations in glycemic control.

Lipoprotein lipids and apolipoproteins (AI, AII, B, CII, CIII) in type 1 and type 2 diabetes mellitus in young Kuwaiti women

Plasma lipid and apolipoprotein levels of Type 1 and Type 2 young Kuwaiti diabetic women on insulin therapy were investigated to elucidate the relationship between coronary artery disease risk factors and lipid levels. Forty Type 1 and 52 Type 2 diabetic women and 45 and 62 corresponding control subjects (matched for age and body mass index) were investigated. In comparison with control subjects, both groups of diabetic patients showed marked increases in total-cholesterol, LDL-cholesterol, triglycerides, very low density triglycerides, apolipoprotein B, glucose, fructosamine, and glycosylated haemoglobin HbA1c (all p less than 0.001). However, apolipoprotein CIII was significantly elevated in Type 2 diabetic patients (p less than 0.001) but not in Type 1 patients. Concentrations of apolipoproteins CII and AII in both diabetic groups were not significantly different from those in control subjects. Levels of HDL-, HDL2- and HDL3-cholesterol and plasma apolipoprotein AI were markedly decreased in both the diabetic groups compared with their control groups (all p less than 0.001 except HDL3-cholesterol in Type 1 diabetic vs control, p less than 0.05). In Type 2 diabetic patients, HbA1c correlated positively with triglycerides (r = 0.70, p less than 0.001), cholesterol (r = 0.60, p less than 0.001), apolipoprotein B (r = 0.77, p less than 0.001), and apolipoprotein CIII (r = 0.55, p less than 0.001) and negatively with apolipoprotein AI (r = -0.49, p less than 0.001). In Type 1 diabetic patients HbA1c correlated positively only with apolipoprotein CIII (r = 0.50, p less than 0.001).

Anti-insulin antibodies and retinopathy in juvenile onset type-1 diabetes

Juvenile diabetics have severe loss of beta cell function and require replacement therapy with insulin. Insulin antigenicity can produce anti-insulin antibodies resulting in allergic reactions and insulin resistance. The role of insulin-anti-insulin antibody complexes in the development and progress of chronic diabetic complications like microangiopathy is not very clear. In the present study, there was statistically a significant trend of higher insulin antibody binding levels in IDDM patients who developed retinopathy. Though there was a trend of higher insulin antibody in IDDM patients with retinopathy, there was no association between insulin antibody and HLA antigen which some authors have reported.

Plasma lipoproteins and apolipoproteins in insulin-dependent and young non-insulin-dependent Arab women

Plasma lipids, lipoproteins and apolipoproteins (apo) were analysed in 30 young Arab IDDM and 50 young insulin-requiring NIDDM women. The mean age of IDDM and NIDDM groups was 20.2 and 34.5 years, and mean duration of diabetes was 5.7 and 4.6 years, respectively. Two groups of 40 and 60 healthy women (matched for age and BMI) provided corresponding control groups. In comparison with control subjects, diabetics showed marked increases in the following parameters: total cholesterol (TC), low density lipoprotein (LDL) cholesterol, total triglycerides (TG), very low density lipoprotein (VLDL) triglycerides, phospholipids, apoB, LDL apoB, glucose and glycosylated hemoglobin (HbA1c) as well as the ratios of total cholesterol/high density lipoprotein (HDL) cholesterol, LDL-cholesterol/HDL-cholesterol, LDL cholesterol/high density lipoprotein (HDL) cholesterol, LDL-cholesterol/HDL-cholesterol, LDL cholesterol/high density lipoprotein 2 (HDL2) cholesterol and apoB/apoAI. Plasma LCAT activity, concentrations of HDL3 apoAI and apoAII in plasma and lipoprotein fractions were normal in both the diabetic groups. Levels of C-peptide, HDL, HDL2 and HDL3 cholesterol, plasma apoAI, HDL apoAI and HDL2 apoAI were markedly decreased in the diabetic groups as compared to their corresponding controls. There was no significant correlation between fasting glucose or HbA1c and any of the above parameters. Despite insulin therapy in both the diabetic groups studied, abnormalities in lipids, apoB and apoAI still persisted. Our data suggest a possible higher risk of atherosclerosis in these patients.

A mathematical model for insulin kinetics. III. Sensitivity analysis of the model

A non-linear mathematical model involving four variables and several constants incorporating beta-cell kinetics, a glucose-insulin feedback system and a gastrointestinal absorption term had been applied in earlier papers to various forms of diabetes mellitus. In this paper, we examine the response of the system to variations in the parameters and to initial conditions using sensitivity analysis. It is found that such a method leads to results that are consistent with clinical findings. Further, it is suggested that such an analysis could help in making some predictions regarding future directions in the therapy of diabetes mellitus.

Plasma renin activity and urinary kallikrein excretion in response to intravenous furosemide in diabetic patients

The responsiveness of renin-angiotensin and kallikrein-kinin systems to furosemide challenge has been investigated in forty-six diabetic patients (34 NIDDM/12 IDDM), subdivided into Group I (uncomplicated DM), Group II (DM with hypertension), Group III (DM with nephropathy), Group IV (DM with hypertension and nephropathy) and a control group of 10 healthy volunteers. Plasma renin activity (PRA) was estimated by radioimmunoassay in blood samples drawn before and 10 min after furosemide administration (0.5 mg/kg i.v.). Urinary kallikrein levels were measured by bioassay using estrogenized rat uterus preparation in 4h urine samples collected before and after the diuretic. Urinary Na+ and K+ were also measured. The basal PRA in diabetics was not significantly different from controls, whereas, urinary kallikrein levels were markedly low in all patients. Both PRA and kallikrein levels increased after furosemide in controls while in diabetics this response was severely blunted. In a subset of Group I, a paradoxical fall in PRA and kallikrein levels was noted after furosemide, an effect similar to that observed in patients with nephropathy (Group III). This response in absence of clinical and biochemical parameters of nephropathy indicates early derangement of renal hemodynamic mechanisms heralding the onset of nephropathy.

A mathematical model for insulin kinetics. II. Extension of the model to include response to oral glucose administration and application to insulin-dependent diabetes mellitus (IDDM)

A generalized nonlinear mathematical model which incorporates beta-cell kinetics, a glucose-insulin feedback system and a gastrointestinal absorption term for glucose, is presented. Numerical simulations using this model lead to time variations of plasma glucose and insulin levels that are consistent with clinical observations in normal groups. The results obtained after suitable reduction in some of the parameters are in agreement with the clinical profile and laboratory data in insulin-dependent diabetes mellitus (IDDM). Linear stability analysis of the equations shows that there is a change in the nature of the stability in the transition from the normal case to IDDM, and it is the decrease in the beta cell function which causes this change.