Diffuse narrowing of coronary arteries in diabetic patients: the earliest phase of coronary artery disease

Coronary arteries in diabetic patients appear to be narrower than in normal subjects, but this has not been examined systematically. To investigate this hypothesis we reviewed the data of 711 consecutive patients with angiographically 'normal coronary arteries'. Excluded were patients with valvular, myocardial or pericardial disease, and patients with hypertension or hyperlipidemia. Thirteen diabetic patients (10 men) and 22 nondiabetic persons (8 men) constituted the study and control groups, respectively. The diameters of the coronary arteries and their branches were measured and adjusted for body surface area. The sum of the proximal left anterior descending (LAD), circumflex and right coronary arteries (RCA) was calculated and defined as total coronary diameter (TCD). The sum of the distal LAD, first diagonal, first marginal and distal RCA was calculated and defined as total distal coronary diameter (dTCD). The clinical data of both groups were comparable. Adjusted TCD for body surface area was 5.4 +/- 1.1 and 6.5 +/- 1.1 mm/m2 (p < 0.05) in diabetics and nondiabetics, respectively, and adjusted dTCD was 4.9 +/- 1.2 and 6.1 +/- 1.2 mm/m2 (p = 0.01) in diabetics and normal subjects, respectively. Specific arteries and branches that were significantly smaller in diabetics included: left main coronary artery, distal LAD, first diagonal, proximal RCA, distal RCA, right ventricular branch, and posterolateral and posterior descending artery of RCA origin. Gender was not a confounding factor since the control group had a larger proportion of women and still larger arteries than the diabetic group. In conclusion, coronary arteries and their branches in diabetic patients have smaller diameters than normal subjects. This may be due to increased coronary tone, diffuse mild atherosclerosis or both.

The association between two common mutations C677T and A1298C in human methylenetetrahydrofolate reductase gene and the risk for diabetic nephropathy in type II diabetic patients

Mutations of the methylenetetrahydrofolate reductase (MTHFR) gene have been shown to be associated with a predisposition to developing diabetic nephropathy (DN) in specific populations. The frequency of two MTHFR mutations, a recently described mutation in the human MTHFR gene A1298C and C677T, whose association with DN is already known, was determined in an Israeli Jewish population with type 2 diabetes mellitus (DM). Both A1298C and C677T are highly prevalent in the diabetic population with allele frequencies of 0.35 and 0.36, respectively. The genotype frequency and allele frequency for these two polymorphisms in patients who are normoalbuminuric (n = 55) were compared with those of patients who had either micro- or macroalbuminuria (n = 43). For both polymorphisms, there were no significant differences in either the genotype distribution or allele frequency in patients with or without DN. However, in patients with serum folate <15.4 nmol/L, there was a greater incidence of DN in those patients who were homozygous or heterozygous for the C677T mutation. For the A1298C mutation, there is evidence suggesting that the homozygous state may be protective in patients with low-normal serum folate. Folate supplementation in diabetic patients with the C677T mutation and low-normal serum folate may prevent the onset or retard the progression of DN.

Renal nitric oxide production during the early phase of experimental diabetes mellitus

BACKGROUND

Diabetic nephropathy (DN) is characterized by hyperfiltration and hypertrophy in experimental models of diabetes mellitus (DM). Several studies have demonstrated that the pathophysiologic and morphologic changes in DN are mediated by either an increase or decrease in renal nitric oxide (NO) production and/or activity. The goal of the present study was to determine the effects that the early diabetic state has on NO production in the kidney of rats with streptozotocin-induced DM.

METHODS

Experimental DM was induced in rats with streptozotocin. Urinary NO production was measured, and levels and activity of the different NOS isoforms were determined by a combination of techniques, including immunoblotting, immunohistochemistry, diaphorase staining, and reverse transcription-polymerase chain reaction.

RESULTS

During the first week of DM, urinary NO metabolites (uNO2 + NO3) were reduced as compared with controls, which were unrelated to changes in serum levels of NO. Total NO synthase (NOS) activity was reduced in the renal cortex beginning at 30 hours after the induction of DM. NADPH diaphorase staining of renal cortical slices showed reduced NOS activity in the macula densa in diabetic animals. By immunohistochemical staining with antibodies to the different isoforms of NOS, it was found that protein levels of the neuroneal NOS (nNOS) isoform was diminished in the macula densa. No changes were found in the levels of endothelial NOS (eNOS) activity and protein in the renal cortex in the early diabetic state.

CONCLUSIONS

This study provides strong evidence that renal production of NO is reduced in early DM and that this reduction is associated with decreased levels of nNOS activity and protein in the macula densa.

Octreotide, a somatostatin analogue, fails to inhibit hypoxia-induced retinal neovascularization in the neonatal rat

OBJECTIVE

Octreotide, a somatostatin analogue, has been shown to prevent angiogenesis in diverse in vitro models. We evaluated its effect on retinal neovascularization in vivo, using a neonatal rat retinopathy model.

METHODS

We used, on alternating days, hypoxia (10% O2) and hyperoxia (50% O2) during the first 14 days of neonatal rats, to induce retinal neovascularization. Half of the rats were injected subcutaneously with octreotide 0.7 microg/g BW twice daily. At day 18 the eyes were evaluated for the presence of epiretinal and vitreal hemorrhage, neovascularization and epiretinal proliferation. Octreotide pharmacokinetics and its effect on serum growth hormone (GH) and insulin-like growth factor I (IGF-I) were examined in 28 rats.

RESULTS

Serum octreotide levels were 667 microg/l two hours after injection, 26.4 microg/l after nine hours and 3.2 microg/l after 14 hours. GH levels were decreased by 40% (p = 0.002) two hours after injection but thereafter returned to baseline. IGF-I levels were unchanged two hours after injection and were elevated by 26% 14 hours after injection (p = 0.02). Epiretinal membranes were highly associated with epiretinal hemorrhages (p < 0.001), while retinal neovascularization was notably associated with vitreal hemorrhages (p < 0.001).

CONCLUSIONS

Twice-daily injections of octreotide failed to produce sustained decrease in serum GH, but produced rebound elevation of serum IGF-I. Accordingly, no statistically significant effect of injections on retinal pathology was noted. This finding, however, does not contradict our assumption that GH suppression may decrease the severity of retinopathy.

Prevalence of diabetes mellitus among workers in Israel: a nation-wide study

The prevalence of diabetes mellitus in Israel has been described in various populations and ranges from 4.1% to 8.9%. However, the large immigration wave in the late 1980s and early 1990s could have affected the previous estimates. Moreover, data from the United states and other countries report a significant proportion of undiagnosed diabetes. The main purpose of this study was to estimate the prevalence and the ratio of undiagnosed/diagnosed diabetes in a large sample of workers. The study involved interviews, anthropometric measurements at the work site, and blood glucose determinations (casual capillary, fasting, and when necessary, 2 h after a 75-gram oral glucose load). Diabetes and impaired glucose tolerance (IGT) were diagnosed according to WHO criteria. Five thousand four hundred sixteen workers participated in the study. Three hundred ten reported to be known diabetics (5.7%), 35 (0.7%) were diagnosed as diabetic during the survey, and an additional 93 (1.8%) were classified as IGT. The ratio undiagnosed/diagnosed diabetes was therefore 1:10. Extrapolation of these results produced an estimate of diabetes prevalence in Israel of 10% among people over age 40 years. It seems that in the Israeli health care system, based on universal health insurance and easy access to primary care, the proportion of undiagnosed diabetes is lower than that described in other countries.

Time course of lipopolysaccharide-induced nitric oxide synthase mRNA expression in rat glomeruli

The decrease in glomerular filtration rate that is characteristic of sepsis has been shown to result from the local glomerular inhibition of endothelial nitric oxide synthase (NOS) by nitric oxide (NO) generated from the inducible isoform of NOS (iNOS). iNOS activation depends on de novo synthesis of both RNA and protein. Therefore it is assumed that several hours are required for its full activation. Yet the renal hemodynamic response in sepsis has been documented as early as 60 minutes after lipopolysaccharide (LPS) administration. Experiments were designed to determine the time course of LPS-induced glomerular iNOS mRNA expression and activity in rats. Rats were treated with LPS (2 mg/kg body weight IP). Kidneys were removed after 1,2, 4, 6, and 16 hours. Glomeruli were isolated and incubated. Nitric oxide generation was measured with a Griess assay, and iNOS mRNA was studied by reverse transcriptase-polymerase chain reaction. Similar time course experiments were repeated in glomeruli isolated from normal rats and exposed to LPS in vitro. A significant increase in iNOS mRNA expression was evident as early as 60 minutes after both in vivo and in vitro administration of LPS. The quantity of iNOS mRNA reached its peak between 2 to 4 hours after administration and declined to baseline levels after 16 hours. Immunohistochemical studies were remarkable for a significant increase in the staining for iNOS in glomeruli 2 hours after the in vivo administration of LPS. Plasma nitric oxide concentration after the in vivo administration of LPS increased from a baseline level of 11.25 +/- 0.8 micromol/L to a peak level of 62.9 +/- 3.8 micromol/L (P < .05 vs baseline) at 4 hours and then decreased to 17.5 +/-1.9 micromol/L at 16 hours. Similar results were obtained when the glomerular generation of nitric oxide after in vivo administration of LPS was measured (2.6 +/- 0.8 pmol/h/microg tissue, 17.2 +/- 2.1 pmol/h/microg tissue (P < .05 vs baseline), and 0.4 +/- 0.65 pmol/h/microg tissue, respectively). These results provide evidence of the rapid activation of glomerular iNOS after in vivo and ex vivo administration of LPS and thus support the role of nitric oxide in the early renal hemodynamic response to LPS.

Characterization of the regulatory region of the human testis-specific form of the pyruvate dehydrogenase alpha-subunit (PDHA-2) gene

The alpha-subunit of human pyruvate dehydrogenase (E(1)) is encoded by two separate genes. The gene located on chromosome X (PDHA-1) is expressed in somatic tissues, whereas the second gene (PDHA-2), located on chromosome 4, is expressed only in post-meiotic spermatogenic cells. A genomic fragment harboring the human gene encoding PDHA-2 has been isolated and approximately 800 nucleotides of the promoter region have been characterized. Functional studies of the promoter indicate the presence of both enhancer and repressor elements that are common to other genes that are only expressed in mature sperm.

Maggot therapy for the treatment of intractable wounds

BACKGROUND

Fly maggots have been known for centuries to help debride and heal wounds. Maggot therapy was first introduced in the USA in 1931 and was routinely used there until the mid-1940s in over 300 hospitals. With the advent of antimicrobiols, maggot therapy became rare until the early 1990s, when it was re-introduced in the USA, UK, and Israel. The objective of this study was to assess the efficacy of maggot therapy for the treatment of intractable, chronic wounds and ulcers in long-term hospitalized patients in Israel.

METHODS

Twenty-five patients, suffering mostly from chronic leg ulcers and pressure sores in the lower sacral area, were treated in an open study using maggots of the green bottle fly, Phaenicia sericata. The wounds had been present for 1-90 months before maggot therapy was applied. Thirty-five wounds were located on the foot or calf of the patients, one on the thumb, while the pressure sores were on the lower back. Sterile maggots (50-1000) were administered to the wound two to five times weekly and replaced every 1-2 days. Hospitalized patients were treated in five departments of the Hadassah Hospital, two geriatric hospitals, and one outpatient clinic in Jerusalem. The underlying diseases or the causes of the development of wounds were venous stasis (12), paraplegia (5), hemiplegia (2), Birger's disease (1), lymphostasis (1), thalassemia (1), polycythemia (1), dementia (1), and basal cell carcinoma (1). Subjects were examined daily or every second day until complete debridement of the wound was noted.

RESULTS

Complete debridement was achieved in 38 wounds (88.4%); in three wounds (7%), the debridement was significant, in one (2.3%) partial, and one wound (2.3%) remained unchanged. In five patients who were referred for amputation of the leg, the extremities was salvaged after maggot therapy.

CONCLUSIONS

Maggot therapy is a relatively rapid and effective treatment, particularly in large necrotic wounds requiring debridement and resistant to conventional treatment and conservative surgical intervention.

Expression of the insulin-like growth factors and their receptors in adenocarcinoma of the colon

AIMS

To study changes in the expression of insulin-like growth factors (IGFs) and their receptors, as well as production of the IGF-I and IGF-II polypeptides, in adenocarcinoma of the colon.

METHODS

Malignant tissue obtained at operation was used. Total RNA was extracted and specific IGF-I and IGF-II and their receptor mRNAs were measured by a solution hybridisation RNase protection assay. IGF-I and IGF-II polypeptides were measured by specific immunoassays.

RESULTS

All normal tissues expressed IGF-II, IGF-I receptor, and IGF-II/mannose-6-phosphate (Man-6-P) receptor. IGF-I mRNA could not be detected but the polypeptide was present in small but equal amounts in normal and malignant tissue. IGF-II was expressed 40 times more abundantly in colonic tumours than in adjacent normal tissue and the concentration of the corresponding polypeptide was twice as high in the malignant tissue. IGF-I receptor expression was increased by a factor of 2.5 and IGF-II/Man-6-P receptor by a factor of 4.

CONCLUSIONS

This study confirms that in adenocarcinoma of the human colon there is increased expression of IGF-I receptor and IGF-II. Furthermore, IGF-II/Man-6-P receptor message is increased and the increase in IGF-II message is accompanied by a doubling of the IGF-II protein in the tumour tissue compared with the adjacent normal tissue. These findings suggest that the IGF-II/Man-6-P receptor may also be involved in development of adenocarcinoma of the colon. There is rapidly accumulating evidence implicating the IGF system in the development of malignancy of the large bowel.

T cell proliferative responses of type 1 diabetes patients and healthy individuals to human hsp60 and its peptides

T cell responses to peptide epitopes of the 60 kDa heat shock protein (hsp60) have been shown to play a role in the pathogenesis of type 1 insulin-dependent diabetes mellitus (IDDM) in mice. To test whether hsp60 autoimmunity might be involved in human type 1 diabetes, we studied T cell proliferative responses (stimulation index; SI) to intact human hsp60, to hsp60 peptides and to a recall antigen (tetanus toxoid) in 25 newly diagnosed type 1 diabetes patients, in 22 type 2 (non-insulin-dependent diabetes mellitus, NIDDM) patients, and in 25 healthy blood donors. There were no significant differences between the T cell responses of the three groups to tetanus toxoid. However, the responses to hsp60 of the type 1 diabetes group (median SI=5) were significantly greater (P<0. 01) than those of the type 2 group (median SI=1.67) and of the blood donors (median SI=1.7). Epitope mapping revealed significant responses to at least seven different peptides, with prevalent responses to the p277 peptide previously mapped in NOD mice and to peptide p32. Thus, newly diagnosed type 1 diabetes patients, similar to prediabetic and newly diabetic NOD mice, show heightened autoimmunity to hsp60 and hsp60 peptides.

The effect of the mode of administration on the hypolipidaemic activity of niacin: continuous gastrointestinal administration of low-dose niacin improves lipid-lowering efficacy in experimentally-induced hyperlipidaemic rats

The effect of different routes and modes of administration of niacin (nicotinic acid) on its hypolipidaemic activity has been evaluated. Our working hypothesis was that the major sites of niacin action are located presystemically (i.e. in the gut wall or the liver, or both) which would make niacin a gastrointestinal drug. For such drugs continuous administration to the gastrointestinal tract is expected to augment their efficacy compared with bolus oral administration or parenteral administration. The hypothesis was examined in two rat models of experimentally induced hyperlipidaemia-Model A, based on a cholesterol-enriched diet, and Model B, in which acute hyperlipidaemia is induced by intraperitoneal administration of triton (225 mg kg(-1)). Continuous administration of niacin into the duodenum at 1.66 mg h(-1) (total dose 40 mg kg(-1) day(-1)) for up to 7 days (Model A) or at 2.22 mg h(-1) over 18 h (Model B) had significantly greater lipid-reducing effects both on total cholesterol and on triglyceride levels (15-25%) and elevation of high-density lipoprotein (HDL) cholesterol levels than did bolus oral administration of the same dose. Continuous duodenal infusion of niacin also had an even greater lipid-reducing effect than continuous intravenous infusion of the drug at the same rate and dose. The results indicate that the site(s) of action are located presystemically and that continuous duodenal administration of a low dose of niacin (40 mg kg(-1)) has a greater lipid-lowering effect than a higher dose (200 mg kg(-1)) administered by peroral bolus administration. These conclusions were validated by administration of a specially designed niacin sustained-release matrix tablet formulation that was non-invasively administered to hyperlipidaemic rats. The hypolipidaemic activity of the sustained-release tablet was of similar magnitude to that resulting from continuous duodenal administration, thus providing a pharmacodynamic rationale for this mode of administration.

Gene expression of insulin-like growth factor-I, its receptor and binding proteins in retina under hypoxic conditions

Hypoxia is the main stimulus for neovascularization in the retina. Insulin-like growth factor-I (IGF-I) is thought to be one of the mediators of this process. Severe persistent hypoxia, as occurs in central retinal artery occlusion, is associated with less retinal neovascularization than relative hypoxia. To study the influence of different types of hypoxia on the IGF system, we used a model of neonatal rat retina that responds with neovascularization to a relative hypoxic stimulus produced by alternating oxygen concentrations in the respired air. We studied the influence of 24-hour hypoxia (10% oxygen), 48-hour hyperoxia (75% oxygen), and relative hypoxia (shifting from 48 hours in 75% oxygen to 24 hours in room air) on the gene expression of IGF-I, IGF-I receptor (IGF-IR), and IGF binding protein-1 (IGFBP-1), IGFBP-2, and IGFBP-3 in retina using a solution hybridization RNase protection assay. Hypoxia induced a significant increase in retinal IGF-IR (178%), IGFBP-2 (227%), and IGFBP-3 (317%) mRNA; however, retinal IGF-I mRNA was reduced, as well as serum growth hormone (GH). Relative hypoxia caused a similar but less pronounced trend in the gene expression of IGF-IR and the binding proteins, whereas retinal IGF-I mRNA was unchanged and serum GH was elevated. Both hypoxia and relative hypoxia may cause IGF system stimulation in the retina through upregulation of IGF-IR and IGFBPs. This stimulation may result in neovascularization. However, during hypoxia, low levels of tissue oxygenation and reduced local production of IGF-I may impede the neovascularization process.

The effect of low dose octreotide administration on renal function and on gene expression of IGF-I axis components in experimental diabetes mellitus

The present study was undertaken to assess the chronic effects of low dose octreotide (Oc) administration in rats with experimental diabetes mellitus (DM). Metabolic and clearance studies were performed in control normal rats, in rats with streptozotocin-induced DM of 1 week duration and in similar DM rats treated with Oc, 10-20 microg/day. Gene expression of IGF-I, IGF-I receptor (IGF-I R) and IGF-binding protein-1 (IGFBP-1) was examined in renal tissue from normal DM animals and DM animals treated with Oc 10, 20 and 100 microg/day. Seven days of Oc administration, 10 microg/day, in rats with experimental DM, was associated with enhanced hyperglycemia, increased glomerular filtration rate and urinary sodium excretion as compared with untreated DM animals. After a higher Oc dose, 20 microg/day, however, there were no significant changes in renal function and in glycemic control. Significant increases in kidney weight and kidney weight/body weight ratio were seen in DM rats as compared with control intact animals. These changes were not affected by Oc therapy in various doses. Induction of DM was associated with a marked increase in renal IGFBP-1 mRNA expression. There were no significant changes in the expression of IGF-I or IGF-I R mRNA. Oc therapy in a low or high dose did not affect gene expression of IGF-I, IGF-I R or IGFBP-1. Thus, the response to chronic low dose Oc administration of DM rats may vary from enhanced hyperglycemia and hyperfiltration to a lack of change in renal function or in glycemic control. Low dose Oc therapy was not associated with significant variations in renal mass or in the gene expression of IGF-I axis components. These findings are at variance with previously published studies which show a suppressive effect of Oc on renal function and growth in experimental diabetes. This apparent discrepancy may be related to the duration of treatment or to a biphasic physiological effect of Oc when used in different doses.

Octreotide prevents the early increase in renal insulin-like growth factor binding protein 1 in streptozotocin diabetic rats

The early renal growth in streptozotocin (STZ)-induced diabetic rats is preceded by a transient rise in renal tissue insulin-like growth factor (IGF)-I concentration. Administration of the long-acting somatostatin analog octreotide to STZ diabetic rats inhibits the early increase in kidney IGF-I and the increase in kidney size without affecting metabolic control. We studied the effects of octreotide treatment on the intrarenal IGF axis at 2 and at 7 days after the induction of STZ diabetes. Two days after induction of diabetes, kidney IGF-I was increased from 850 +/- 43 ng/g tissue in controls to 1,648 +/- 165 ng/g tissue (P < 0.001) in diabetic animals. The diabetes-associated increase in renal IGF-I 48 h after STZ injection was totally prevented by octreotide (IGF = 780 +/- 57 ng/g tissue). However, 7 days after the induction of diabetes, kidney IGF-I was similar to that of control and was not affected by octreotide. No difference in serum IGF-I was observed between controls and diabetic rats after 2 days of diabetes; however, octreotide treatment resulted in a significant decrease of serum IGF-I after 2 days when compared with control rats (P < 0.05). Renal IGF-I mRNA was significantly decreased to the same extent in both diabetic groups 2 and 7 days after the induction of diabetes, while renal IGF-I receptor (IGF-IR) mRNA was unchanged in rats from either group. Two days after induction of diabetes, renal insulin-like growth factor binding protein (IGFBP)-1 mRNA and 30-kDa IGFBPs (containing IGFBP-1) increased by 186 and 192%, respectively, in untreated diabetic animals compared with controls. Octreotide treatment prevented the diabetes-associated rise in renal IGFBP-1 mRNA and protein. However, 7 days after the induction of diabetes, renal IGFBP-1 mRNA and protein were similarly increased in both octreotide-treated or untreated diabetic rats. Renal IGFBP-3 gene expression and protein and IGFPB-5 mRNA remained unchanged after 2 and 7 days of diabetes when treated or untreated with octreotide. We conclude that the well-known inhibitory effect of octreotide on the early increase in renal IGF-I concentration and renal size in diabetes may be mediated through a direct effect on renal IGFBP-1 levels.

Hypoglycaemia following pancreatic allograft transplantation

Pancreatic transplantation is an established treatment for patients with insulin-dependent diabetes mellitus. Side-effects are mainly related to surgical complications, immunosuppressive therapy and graft rejection. We report on two patients having recurrent hypoglycaemic events following pancreatic transplantation. The cause of hypoglycaemia in our patients remained obscure. Hypoglycaemia following pancreatic transplantation has been described. Hypoglycaemic events may appear years after transplantation. In the article we review three possible mechanisms of hypoglycaemia: hyperinsulinaemia, secondary to systemic drainage (due to loss of first pass hepatic insulin clearance), presence of anti-insulin antibodies and persistence of counter-regulatory abnormalities. Physicians and patients should be aware of possible hypoglycaemia events following transplantation.

The endogenous insulin-like growth factor system in radiocontrast nephropathy

The response of insulin-like growth factor (IGF) I in acute renal failure was evaluated in a model of radiocontrast nephropathy associated with selective necrosis of medullary thick ascending limbs. In brief, rats were administered radiocontrast medium or vehicle injections for controls after combined inhibition of prostanoids and nitric oxide. Twenty-four hours after the insult, tissue mRNAs for IGF-I, the IGF-I receptor, and IGF-binding proteins (IGFBP) 1 and 3 were assayed in cortex, medulla, and liver by solution hybridization-RNase protection assay, and IGFBPs were measured in serum and tissue by Western ligand blotting. Cortical IGF-1 increased, whereas medullary IGF-I mRNA decreased. Renal IGFBPs decreased, whereas IGFBP-1 mRNA increased. The IGF system in the liver was unchanged. We conclude that general changes in renal IGFBPs in this experimental model of acute renal failure might increase the level of cortical IGF-I in a way that could modulate medullary recovery.

Comparison of factors associated with 30-day mortality after coronary artery bypass grafting in patients with versus without diabetes mellitus. Israeli Coronary Artery Bypass (ISCAB) Study Consortium

The purpose of this study was to identify factors associated with 30-day mortality after coronary artery bypass graft surgery (CABG) among diabetic patients, and to compare them with risk factors among nondiabetics. A subanalysis of a prospective national cohort study was performed which included patients who underwent CABG in 14 medical centers in Israel during 1994. Data including patient demographic and historical information, comorbidity, and cardiac catheterization results were collected by trained nurses. Data were derived from direct patient interviews, charts, catheterization reports, surgical reports, and national vital records. Multivariate logistic regression analysis was used to identify factors associated with a 30-day mortality in diabetic and nondiabetic patient populations. The results showed that crude mortality was 5.0% among diabetic patients (n = 1,034) and 2.5% among nondiabetics (n = 3,350; p < 0.001). The risk profile in diabetics was found to be worse. Multivariate logistic regression analysis identified female gender, 3-vessel disease, and left main disease as independent risk factors for 30-day, past-CABG mortality unique to diabetic patients. Left ventricular dysfunction was found to effect a greater risk among diabetic patients, whereas chronic renal failure was associated with greater risk among nondiabetics. In conclusion, we found differences in patterns of risk factors for post-CABG mortality between diabetics and nondiabetics. These findings may help physicians to identify patients at high risk for CABG mortality.

Effect of acute N-nitro-L-arginine methyl ester (L-NAME) hypertension on glucose tolerance, insulin levels, and [3H]-deoxyglucose muscle uptake

This study was conducted to test the hypothesis that acute, widespread N-nitro-L-arginine methyl ester (L-NAME) induced vasoconstriction and hypertension may affect glucose tolerance and insulin sensitivity in normal rats. Comparisons were made of blood pressure, intravenous glucose tolerance, and insulin response and [3H]-deoxyglucose tissue uptake between L-NAME and control treated rats. Chronically instrumented, awake rats were administered L-NAME (30 mg/kg) (n = 8) or saline (0.3 mL) (n = 8) intravenously. After blood pressure stabilized, a bolus injection containing glucose (300 mg/kg) and trace [3H]-deoxyglucose was administered. Arterial blood was sampled for evaluation of glucose tolerance, insulin response, and [3H]-deoxyglucose muscle uptake. L-NAME treated rats had a persistent 54 +/- 4 mm Hg blood pressure rise while fasting, and postload plasma glucose and insulin responses did not differ, nor did heart and striated muscle [3H]-deoxyglucose uptake differ. In conclusion, acute L-NAME induced hypertension does not result in glucose intolerance, hyperinsulinemia, or decreased [3H]-deoxyglucose muscle uptake.

Role of reactive oxygen species in diabetes-induced embryotoxicity: studies on pre-implantation mouse embryos cultured in serum from diabetic pregnant women

Sera from diabetic patients or sera with high levels of diabetic metabolic products, were found to affect mouse and rat blastocysts. In the present study we examined the earliest developmental stages at which human diabetic serum will be lethal to mouse pre-implantation embryos, and whether reactive oxygen species (ROS) are involved in these diabetes-induced injuries. We cultured 2-4 cell-stage embryos and blastocysts in a medium containing 30 or 50% serum obtained from pregnant women with diabetes Type I, Type II and gestational diabetes (GDM) for 72 h. The development of the 2-4 cell-stage embryos was delayed when cultured in 30% diabetic serum, but the viability was impaired to a lesser extent. Viability was reduced in blastocysts cultured in 50% diabetic serum, but the development of the living embryos was not delayed. Cyclic voltametry measures the oxidation potential of the tissue and the concentration of antioxidants, thus reflecting the total antioxidative activity of the embryos. Pre-implantation embryos cultured in diabetic serum had a lower concentration of antioxidants than embryos cultured in non-diabetic serum. It seems, therefore, that diabetic metabolic factors may induce embryotoxicity in pre-implantation embryos through derangement of the antioxidant defense mechanism. A similar mechanism is suggested for the diabetes-induced teratogenicity in post-implantation embryos.

Dyslipidaemia in polycystic ovarian syndrome: different groups, different aetiologies?

The objective was to study the pathophysiology of the dyslipidaemia in polycystic ovarian syndrome (PCOS) patients, and to determine how it is related to hyperinsulinaemia, hyperandrogenism and dehydroepiandrosterone sulphate (DHEA-S) concentrations. The lipoprotein lipid profile, anthropometric measurements, endocrine profile and the presence of insulin resistance were evaluated in 31 PCOS patients and 20 age-matched healthy women, who served as controls. PCOS patients had higher fasting insulin concentrations, higher body mass indexes (BMI) and were hyperlipidaemic, with higher total cholesterol, low density lipoprotein (LDL) and triglyceride (TG) concentrations. There were no relationships between plasma lipids and anthropometric variables in the patient group as a whole. Insulin-resistant (IR) and non-IR (NIR) PCOS patients were then evaluated separately. Obesity with marked hyperandrogenism were the predominant features in patients with IR. NIR patients were not obese and had significantly less hyperandrogenism. The adrenal androgen DHEA-S was at the upper limit of its normal range in both groups. However, both PCOS subgroups exhibited similar significant abnormalities in terms of their lipid parameters. Insulin and DHEA-S concentrations were positively correlated with total cholesterol, LDL and TG, and negatively correlated with high density lipoprotein, in IR patients. In NIR subjects, insulin was not correlated with any of the lipids and DHEA-S was negatively related to cholesterol and LDL. Anthropometric variables were related to lipids in only the NIR patients. Thus PCOS subjects as a group exhibit dyslipidaemia, characterized by increased total cholesterol, LDL and TG concentrations. When divided into IR and NIR subjects, there were no differences in the degree of lipid abnormalities, despite significant variations in the BMI and androgen status. Thus, in PCOS subjects, dyslipidaemia may occur irrespective of insulin resistance. Insulin and DHEA-S concentrations were positively correlated with an atherogenic lipid profile in the IR group only. As distinct from syndrome X when IR was present, dyslipidaemia was not related to body weight or the waist:hip ratio. In the NIR group there was no relationship between lipids and insulin; DHEA-S, on the other hand, was negatively related to cholesterol and LDL concentrations. Thus, dyslipidaemia in PCOS patients may occur irrespective of insulin resistance, and may have different metabolic aetiologies depending on DHEA-S metabolism. It remains to be seen whether the two types of PCOS are associated with different risks for ischaemic heart disease.

Pre-clinical Cushing's syndrome: an unexpected frequent cause of poor glycaemic control in obese diabetic patients

OBJECTIVE

Autonomous cortisol secretion without clinical stigmata of Cushing's syndrome (CS) has been recently recognized and termed pre-clinical or sub-clinical CS. The common assumption is that CS is an extremely rare cause of uncontrolled diabetes; however, the prevalence of this entity has not been studied. We assessed the prevalence of pre-clinical CS among obese patients with uncontrolled diabetes.

PATIENTS AND DESIGN

(1) In a retrospective analysis, the medical records of 63 patients with endogenous CS were reviewed. (2) In a cross-sectional study, 90 obese patients (BMI > 25 kg/m2) followed in a University Hospital and the local Health Fund endocrine and diabetes clinics, with poorly controlled diabetes (glycosylated haemoglobin > 9%), underwent an overnight 1 mg dexamethasone suppression. In patients with non-suppressible cortisol levels (> 140 nmol/l), Liddle's 2 and 8 mg dexamethasone suppression tests and imaging studies were performed.

MEASUREMENTS

The prevalence of poorly controlled diabetes, the major presenting symptom of CS, was assessed in the retrospective analysis. The prevalence of "true' CS and the false positive rate in the overnight dexamethasone suppression test were calculated. The endocrine evaluation of the patients with pre-clinical CS and the effects of surgical cure on glycaemic control are described.

RESULTS

In the retrospective analysis, 11 (17.5%) had diabetes and 2 (3.2%) lacked the classic physical characteristics of the syndrome. In the cross-sectional study, 4 patients failed to suppress plasma cortisol (< 140 nmol/l). In one patient the diagnosis of CS was not confirmed by a standard Liddle's test and was therefore considered false positive. In the other 3, the diagnosis of CS was confirmed (prevalence of 3.3%, 95% confidence interval 1-9%). In all other patients the overnight cortisol suppression test was normal (cortisol level 47.3 +/- 2.5 nmol/l (mean +/- SEM)). After surgical treatment of CS, glycaemic control was markedly improved in all 5 patients (2 from retrospective and 3 from cross-sectional studies).

CONCLUSIONS

The prevalence of pre-clinical Cushing's syndrome in obese patients with poorly controlled diabetes appears to be considerably higher than previously believed. The overnight dexamethasone suppression test proved to be a simple, sensitive and highly specific screening test for Cushing's syndrome despite the presence of obesity and hyperglycaemia.

A patient with hypoparathyroidism, dysmorphic features and mental retardation

There have been various reports in the medical literature concerning children with syndromes of congenital hypoparathyroidism, seizures, dysmorphic features and mental retardation. We describe a patient with hypoparathyroidism, mental retardation, micrognathia, deep-set eyes and pes cavus in a 31-year-old man. This combination of abnormalities in an adult is unique.

Rapid activation of glycogen synthase and protein phosphatase in human skeletal muscle after isometric contraction requires an intact circulation

The effects of isometric contraction (66% of maximal force) and recovery on glycogen synthase fractional activity (GSF) in human skeletal muscle have been studied. Biopsies were taken from the quadriceps femoris muscle at rest, at fatigue and 5 min postexercise on two occasions: after one of the contractions, the circulation to the thigh was occluded during the 5 min recovery (OCC), and after the other contraction, the circulation was intact (control, CON). During CON, GSF decreased from (mean +/- SE) 0.34 +/- 0.05 at rest to 0.24 +/- 0.02 at fatigue and then increased to 0.74 +/- 0.04 at 5 min postexercise; corresponding values for OCC were 0.37 +/- 0.04, 0.25 +/- 0.04 and 0.48 +/- 0.05 (P < 0.001 vs. CON for 5 min postexercise only). Compared with the value at fatigue, protein phosphatase activity (PP) increased by 79 +/- 16% during CON recovery (P < 0.01), whereas no change was observed during OCC recovery. Uridine diphosphate glucose increased by approximately 2.5-fold at fatigue, remained elevated during OCC recovery, but reverted to the preexercise level during CON recovery (P < 0.001 vs. OCC recovery). Glucose 6-P increased approximately 5-fold at fatigue and was higher at 5 min postexercise in OCC vs. CON recovery (8.6 +/- 1.5 vs. 4.1 +/- 0.9 mmol/kg dry wt; P < 0.01). It is concluded that the rapid increase in GSF after intense exercise with an intact circulation may be at least partly attributed to an increase in the specific activity of PP. The increase in GSF during recovery in OCC may be at least partly attributed to the high glucose 6-P content in vivo, which enhances the substrate suitability of GS for PP. Thus, separate mechanisms exist for the activation of PP and GS during recovery from intense short term exercise.