Aspirin in type 2 diabetes, a randomised controlled study: effect of different doses on inflammation, oxidative stress, insulin resistance and endothelial function.

OBJECTIVES: The effect of aspirin upon platelet function is well documented although experimental studies suggest that aspirin may also affect oxidative stress, vascular inflammation, endothelial dysfunction and dysglycaemia. The optimal dose of aspirin for cardiovascular protection in type 2 diabetes is still debated. We examined the effects of different doses of aspirin upon these novel markers of cardiovascular risk and any association between aspirin-mediated changes in these markers. METHODOLOGY: Subjects with type 2 diabetes attended for baseline evaluation including BMI, glycaemic and lipid markers, endothelial function (photoplethysmography), insulin resistance (HOMA), inflammation (sVCAM-1 and Hs-CRP) and markers of oxidative stress [total anti-oxidant status (TAOS and FRAP), whole blood total glutathione (GSH) assays]. Subjects then received in random, sequential, blinded fashion aspirin 75 mg day(-1) , aspirin 300 mg day(-1) , aspirin 3.6 g day(-1) or placebo for 2 weeks with a 2-week washout. The above investigations were repeated after each intervention. Aspirin-related changes compared with placebo were analysed using repeated measures ANOVA. RESULTS: Subjects = 17 (M - 12; F - 5), mean age - 57.4 ± 9.1 years (mean ± 1 SD), HbA1c - 63 ± 13 mmol mol(-1) (7.9 ± 1.2%), total cholesterol 4.57 ± 1.01 mmol l(-1) . At baseline TAOS value was 59.3 ± 9.7 µM AEAC (Ascorbate Equivalent Anti-oxidant Concentration), glutathione 302.2 ± 183.3 mmol l(-1) and FRAP 0.86 ± 0.23 mM FeII. None of the aspirin doses had a significant impact upon BMI, blood pressure, lipid parameters, insulin sensitivity (HOMA), FRAP, TAOS, GSH, endothelial function, glycaemic control (fructosamine) or inflammation (sVCAM-1 and HsCRP). CONCLUSIONS: Aspirin exhibited no significant dose-dependent effect on markers of vascular inflammation, oxidative stress, insulin resistance and endothelial function (photoplethysmography) when used in type 2 diabetes over a 2-week period. ( CLINICAL TRIALS REGISTRATION: NCT00898950, EUDRACT:2004-001418-14).

Thiamine deficiency in diabetes mellitus and the impact of thiamine replacement on glucose metabolism and vascular disease.

Despite the targeting of traditional risk factors for cardiovascular disease, disease burden has not been completely eliminated. Thiamine is an essential cofactor in carbohydrate metabolism and individuals with diabetes are thiamine deficient. The pathophysiology of recognised complications of thiamine deficiency is similar to that underlying atherosclerosis and the metabolic syndrome, namely oxidative stress, inflammation and endothelial dysfunction. This review examines the mechanisms by which thiamine deficiency occurs in individuals with diabetes, how this deficiency leads to hyperglycaemic-induced damage, and the effect of thiamine replacement on vascular disease, endothelial function and oxidative stress. Thiamine administration can prevent the formation of harmful by-products of glucose metabolism, reduce oxidative stress and improve endothelial function. The potential benefit of long-term replacement in those with diabetes is not yet known but may reduce cardiovascular risk and angiopathic complications.

The effect of oral folic acid upon plasma homocysteine, endothelial function and oxidative stress in patients with type 1 diabetes and microalbuminuria.

AIMS: The purpose of this study was to investigate the effect of oral folic acid supplementation upon plasma homocysteine (HCY), endothelial function and oxidative stress on patients with type 1 diabetes and microalbuminuria to test the hypothesis that oral folic acid would lower plasma HCY and thereby improve endothelial function and reduce oxidant stress in this high-risk group of patients. METHODS: We measured plasma HCY, forearm blood flow, total antioxidant status and whole blood glutathione at baseline and after 2 months treatment with oral folic acid or placebo in 16 patients with type 1 diabetes and microalbuminuria. RESULTS: Plasma HCY fell by 25% in the folic acid group but there was no difference in endothelial function or markers of oxidant stress in the treatment group. CONCLUSIONS: Oral folic acid supplementation successfully lowered plasma HCY levels in patients with type 1 diabetes and microalbuminuria, however this was not associated with improvements in endothelial function or markers of oxidant stress.

Characteristics of insulin-Naïve people with type 2 diabetes who successfully respond to insulin glargine U100 after 24 weeks of treatment: a meta-analysis of individual participant data from 3 randomized clinical trials.

BACKGROUND: To identify baseline/clinical characteristics associated with clinically meaningful responses to insulin glargine 100 U/mL (IGlar) in insulin-naive people with type 2 diabetes mellitus (T2DM). METHODS: Individual participant data were pooled from 3 randomized trials to compare baseline characteristics and clinical outcomes associated with 24-week response to IGlar in combination with non-insulin antihyperglycemic agents in participants with T2DM. Responders were defined as achieving endpoint HbA1c target < 53 mmol/mol (< 7%) and/or ≥ 11 mmol/mol (≥ 1%) HbA1c reduction from baseline. RESULTS: Differences in baseline characteristics for responders versus nonresponders were higher HbA1c (99 vs 91 mmol/mol [9.1 vs 8.3%]; P < 0.001), higher fasting blood glucose (FBG; 10.4 vs 8.8 mmol/L [187 vs 159 mg/dL; P < 0.001), and fewer participants (94% vs 98%; P = 0.006) taking oral medications targeting postprandial blood glucose (BG). Most participants (80%) achieved one or both components of composite endpoint. 12-week response was a strong predictor of subsequent 24-week response (sensitivity, 85.9%; predictive positive value, 91.4%). At both 12 and 24 weeks, < 40% of responders and nonresponders reached target FBG ≤ 5.6 mmol/L (≤ 100 mg/dL). Responders at 24 weeks had higher incidence of hypoglycemia (total, 82.5% vs 70.4%; P < 0.001; nocturnal, 60.3% vs 50.5%; P = 0.002; documented symptomatic, 65.8% vs 55.6%; P < 0.001) than nonresponders. CONCLUSIONS: Baseline characteristics associated with response were identified. The strong predictability of 12-week response suggests that the magnitude of early HbA1c reduction should be considered when assessing response to IGlar. More aggressive IGlar titration may be reasonable for nonresponders and responders who have not reached FBG and HbA1c targets, taking into account other BG timepoints.

Acute hyperinsulinemia decreases the hepatic secretion of very-low-density lipoprotein apolipoprotein B-100 in NIDDM.

In a randomized crossover study, we measured the hepatic secretion rate of very-low-density lipoprotein (VLDL) apolipoprotein B-100 (apoB) in seven patients with well-controlled non-insulin-dependent diabetes mellitus (NIDDM) (HbA1 8.4 +/- 0.4% [mean +/- SE]) on two occasions: during a 13-h hyperinsulinemic (plasma insulin concentration 586 +/- 9.7 pmol/l) euglycemic (plasma glucose concentration 5.2 +/- 0.1 mmol/l) clamp; and during a 13-h saline (control) infusion. After 5 h of the hyperinsulinemic euglycemic clamp (or saline infusion) when a new steady state of apoB turnover was reached, [1-(13)C]leucine was administered by a primed (1 mg/kg), constant 8-h infusion (1 mg.kg-1. h-1). VLDL apoB isotopic enrichment was determined with gas chromatography-mass spectrometry, and a monoexponential model was used to calculate the fractional secretion rate of VLDL apoB. VLDL apoB secretion rate was significantly reduced during the hyperinsulinemic euglycemic clamp compared with the saline study (12.2 +/- 3.6 vs. 24.5 +/- 7.1 mg.kg-1.day-1, P = 0.001), but there was no change in the fractional catabolic rate of VLDL apoB. Concomitantly, plasma concentrations of nonesterified fatty acids (NEFAs), glycerol, and triglycerides (TGs) were significantly lower during the hyperinsulinemic euglycemic clamp compared with the saline study (NEFAs, P < 0.001; glycerol, P = 0.005; TGs P = 0.004). We conclude that acute hyperinsulinemia decreases the hepatic secretion rate of VLDL apoB in NIDDM, probably in part due to reduction in the delivery of NEFA and glycerol substrate to the liver.

Recurrent severe hyperandrogenism during pregnancy: a case report.

This report describes the case of a 28 year old woman with virilisation occurring in two successive pregnancies. Recurrent maternal virilisation is rare (seven previous reports) and this case is unique in its severity. Differential diagnoses include ovarian disease and fetal aromatase deficiency. New techniques to exclude a fetal cause were used in this case. This patient presented during the third trimester of her first pregnancy with rapid onset of hirsuitism, increased musculature, and deepening voice. A blood hormone profile revealed significant hyperandrogenism (testosterone, 72.4 nmol/litre; normal range, 0.5-3.0). She delivered a normal boy and maternal androgen concentrations returned rapidly to normal (testosterone, 0.8 nmol/litre). She presented two years later, during her second pregnancy, with similar symptoms and biochemistry (testosterone, 47.5 nmol/litre). Again, she delivered a healthy normal boy and androgens returned immediately to normal (serum testosterone, 2.0 nmol/litre). Ultrasonography revealed no evidence of ovarian (or adrenal) masses in either pregnancy. Umbilical cord venous blood sampling and placental assays revealed no evidence of fetal aromatase deficiency. Recurrent hyperandrogenism during pregnancy is rare. Ovarian luteoma rarely recurs and hyperreactio luteinalis does not lead to such pronounced androgen concentrations. Therefore, this patient has a unique ovarian condition that could be harmful to offspring and mother.

Cardiovascular risk in women with polycystic ovarian syndrome (PCOS).

AIMS: Studies have suggested that polycystic ovary syndrome (PCOS) is associated with increased cardiovascular risk. The aim of this study was to examine cardiovascular risk profiles in women with PCOS compared with healthy age and weight matched control subjects using novel biochemical and biophysical markers. METHODS: After ethics committee approval, 11 women with PCOS and 12 controls were recruited (mean age, 32; SD, 6.5 years; mean body mass index (BMI), 33.1; SD, 5.9 kg/m2). Serum was analysed for lipid and lipoprotein profile (total and high density lipoprotein cholesterol, triglycerides, apolipoprotein B-100, apolipoprotein A1, lipoprotein (a)), and sialic acid, fibrinogen, homocysteine, and C reactive protein (CRP) concentrations. Endothelial function was also assessed by a standard venous occlusion plethysmography technique to measure reactive hyperaemic forearm blood flow (RH), and expressed as per cent increase from baseline. RESULTS: There were no significant differences in glucose, lipid, or lipoprotein concentrations between the two groups. Furthermore, sialic acid (PCOS: mean, 70.5; SD, 149 mg/litre; controls: mean, 71.3; SD, 112 mg/litre), fibrinogen (PCOS: mean, 3.1; SD, 1.0 g/litre; controls: mean, 3.3; SD, 0.7 g/litre), CRP (PCOS: mean, 4.6; SD, 4.2 mg/litre; controls: mean, 5.41 SD, 5.5 mg/litre), and RH (PCOS: mean, 158.7; SD, 135.5%; controls: mean, 200.1; SD, 114.2%) were similar. CONCLUSIONS: There were no differences in surrogate markers of the processes linked to enhanced cardiovascular risk between patients with PCOS and weight matched controls.

Dyslipidaemia in Adult Growth Hormone (GH) Deficiency and the Effect of GH Replacement Therapy: A Review.

Adult growth hormone (GH) deficiency is associated with a lipid profile known to be related to atherosclerosis. GH replacement therapy improves the lipid profile with the exception of lipoprotein (a) concentrations, which tend to increase after GH therapy. Plasma lipid concentrations depend on its plasma carriers, the lipoproteins. Possible mechanisms involved in the dyslipidaemia of GH-deficient patients and the effects of GH replacement therapy are discussed with a special focus on hepatic lipoprotein metabolism.

Effects of cyclo-oxygenase inhibition on vasodilatory response to acetylcholine in patients with type 1 diabetes and nondiabetic subjects.

OBJECTIVE: Studies examining vasodilatory responses to acetylcholine (ACh) and its derivatives have been conflicting. Enhanced activation of the cyclo-oxygenase pathway and increased availability of vasodilatory prostanoids may occur in type 1 diabetes, and this may compensate for the observed reduction in nitric oxide (NO) activity We examined the role of cyclo-oxygenase inhibition on vasodilatory responses in 12 healthy normotensive type 1 diabetic adults and 12 nondiabetic control subjects of similar age, sex, and BMI. RESEARCH DESIGN AND METHODS: Forearm blood flow was measured using a venous occlusion plethysmography technique at baseline and after brachial artery infusions of ACh (7.5, 15, and 30 microg/min). Forearm blood flow at baseline and after ACh was then reexamined after local intra-arterial infusion of indomethacin (0.3 mg/100 ml forearm volume), a cyclo-oxygenase inhibitor. RESULTS: Baseline blood flow in the diabetic and control groups were similar (2.65 +/- 0.26 vs. 2.59 +/- 0.20 ml/min per 100 ml, respectively; P = 0.4). After indomethacin infusion, the vasodilatory responses to all doses of ACh were reduced in both the diabetic (by 25.30 +/- 4.90%) and control group (by 11.23 +/- 5.45%). However, the reduction in blood flow response to ACh after indomethacin was greater in diabetic patients compared with control subjects (P = 0.03). CONCLUSIONS: Our findings suggest that vasodilatory, prostanoids are important in determining endothelial response to ACh in diabetic and nondiabetic subjects. Increased prostaglandin-mediated vasodilation may compensate for attenuated responses to NO previously reported in diabetic subjects. These findings may partly explain the conflicting reports of endothelial dysfunction in patients with type 1 diabetes.

Effects of growth hormone (GH) replacement therapy on low-density lipoprotein apolipoprotein B100 kinetics in adult patients with GH deficiency: a stable isotope study.

GH replacement therapy has been shown to improve the dyslipidemic condition in a substantial proportion of patients with adult GH deficiency. The mechanisms are not yet fully elucidated. Low-density lipoprotein (LDL) apolipoprotein B100 (apoB) formation and catabolism are important determinants of plasma cholesterol concentrations. This study examined the effect of GH replacement therapy on LDL apoB metabolism using a stable isotope turnover technique. LDL apoB kinetics was determined in 13 adult patients with GH deficiency before and after 3 months GH/placebo treatment in a randomized, double-blind, placebo-controlled study. LDL apoB (13)C-leucine enrichment was determined by isotope-ratio mass spectrometry. Plasma volume was assessed by standardized radionuclide dilution technique. GH replacement therapy significantly decreased LDL cholesterol, LDL apoB concentrations, and LDL apoB pool size compared with placebo. Compared with baseline, GH replacement therapy resulted in a significant increase in plasma volume and fractional catabolic rate, whereas LDL formation rate remained unchanged. LDL lipid content did not significantly change after GH and placebo. This study suggests that short-term GH replacement therapy decreases the LDL apoB pool by increasing removal of LDL particles without changing LDL composition or LDL apoB production rate. In addition, it is possible that the beneficial effects of GH on the cardiovascular system contribute to these findings.

Abnormalities of very low density lipoprotein apolipoprotein B-100 metabolism contribute to the dyslipidaemia of adult growth hormone deficiency.

Increased cardiovascular mortality in adult growth hormone deficiency (GHD) may be, in part, explained by the dyslipidaemia associated with this condition. It is possible that abnormalities of very low density lipoprotein apolipoprotein B-100 (VLDL apoB) metabolism contribute to this dyslipidaemia. To test this hypothesis, we measured VLDL apoB kinetics in adult GH deficient patients (4 females, 3 males; age 50.1 +/- 4.7 yr (mean +/- SEM); BMI 28.2 +/- 1.1 kg/m2; total cholesterol (TC) 6.6 +/- 0.3 mmol/l; triglyceride (TG) 2.8 +/- 0.6 mmol/l; HDL cholesterol 1.1 +/- 0.1 mmol/l) and in control subjects (4 females, 3 male; age 47.0 +/- 4.7 yr; BMI 27.0 +/- 2.6 kg/m2; TC 5.0 +/- 0.4 mmol/l; TG 0.9 +/- 0.2 mmol/l; HDL cholesterol 1.4 +/- 0.1 mmol/l). [1-(13)C] leucine was administered by a primed (1 mg/kg), constant intravenous infusion (1 mg/kg/hr) and VLDL apoB enrichment with 13C leucine was determined using gas-chromatography mass-spectrometry. The GHD patients had a significantly higher hepatic secretion rate of VLDL apoB (15.5 +/- 1.8 mg/kg/day vs 9.4 +/- 0.6 mg/kg/day p = 0.007) and reduced catabolism ofVLDL apoB (metabolic clearance rate; 12.3 +/- 1.7 ml/min vs 24.3 +/- 4.8 ml/min p < 0.05) compared with control subjects. These findings suggest that GH is integrally involved in the regulation of VLDL apoB metabolism.

The importance of growth hormone in the regulation of erythropoiesis, red cell mass, and plasma volume in adults with growth hormone deficiency.

Total body water (TBW) is reduced in adult GH deficiency (GHD) largely due to a reduction of extracellular water. It is unknown whether total blood volume (TBV) contributes to the reduced extracellular water in GHD. GH and insulin-like growth factor I (IGF-I) have been demonstrated to stimulate erythropoiesis in vitro, in animal models, and in growing children. Whether GH has a regulatory effect on red cell mass (RCM) in adults is not known. We analyzed body composition by bioelectrical impedance and used standard radionuclide dilution methods to measure RCM and plasma volume (PV) along with measuring full blood count, ferritin, vitamin B12, red cell folate, IGF-I, IGF-binding protein-3, and erythropoietin in 13 adult patients with GHD as part of a 3-month, double blind, placebo-controlled trial of GH (0.036 U/kg.day). TBW and lean body mass significantly increased by 2.5 +/- 0.53 kg (mean +/- SEM; P < 0.004) and 3.4 +/- 0.73 kg (P < 0.004), respectively, and fat mass significantly decreased by 2.4 +/- 0.32 kg (P < 0.001) in the GH-treated group. The baseline RCM of all patients with GHD was lower than the predicted normal values (1635 +/- 108 vs. 1850 +/- 104 mL; P < 0.002). GH significantly increased RCM, PV, and TBV by 183 +/- 43 (P < 0.006), 350 +/- 117 (P < 0.03), and 515 +/- 109 (P < 0.004) mL, respectively. The red cell count increased by 0.36 +/- 0.116 x 10(12)/L (P < 0.03) with a decrease in ferritin levels by 39.1 +/- 4.84 micrograms/L (P < 0.001) after GH treatment. Serum IGF-I and IGF-binding protein-3 concentrations increased by 3.0 +/- 0.43 (P < 0.001) and 1.3 +/- 0.15 (P < 0.001) SD, respectively, but the erythropoietin concentration was unchanged after GH treatment. No significant changes in body composition or blood volume were recorded in the placebo group. Significant positive correlations could be established between changes in TBW and TBV, lean body mass and TBV (r = 0.78; P < 0.04 and r = 0.77; P < 0.04, respectively), and a significant negative correlation existed between changes in fat mass and changes in TBV in the GH-treated group (r = -0.95; P < 0.02). We conclude that 1) erythropoiesis is impaired in GHD; 2) GH stimulates erythropoiesis in adult GHD; and 3) GH increases PV and TBV, which may contribute to the increased exercise performance seen in these patients.

The effect of recombinant human growth hormone on glucose and leucine metabolism in Cushing's syndrome.

Cushing's syndrome is characterized by central obesity and muscle wasting. As GH is anabolic, it may be able to counteract the loss of body protein. To evaluate the potential therapeutic use of GH preoperatively, eight patients with Cushing's syndrome received sc injections of recombinant human GH (0.07 U/kg.day) for 7 days. Whole body leucine and glucose turnover were measured after an infusion of [1-13C]leucine and [6,6-2H2]glucose before (day 0) and after 2 and 7 days of GH treatment. Compared with the value on day 0, there was a significant increase on days 2 and 7 in insulin (P < 0.005 and P < 0.001), C peptide (P < 0.01 and P < 0.005), insulin-like growth factor I (P < 0.001), and glucose concentrations (P < 0.01 and P < 0.005) and a decrease in the leucine concentration (P < 0.005). There was no significant change in glucose production rate, glucose MCR, leucine production rate (a measure of protein degradation), or nonoxidative leucine disappearance rate (a measure of protein synthesis). The leucine MCR was increased after 7 days (P < 0.05), and the clearance of leucine into protein (nonoxidative leucine disappearance rate/leucine concentration) was increased (P < 0.05) after 2 and 7 days of GH treatment. This is consistent with GH stimulating the availability of amino acid transporters. GH may, therefore, have a therapeutic role in the preoperative treatment of Cushing's syndrome.

Effects of growth hormone (GH) replacement therapy on very low density lipoprotein apolipoprotein B100 kinetics in patients with adult GH deficiency: a stable isotope study.

Patients with adult GH deficiency are often dyslipidemic and may have an increased risk of cardiovascular disease. The secretion and clearance of very low density lipoprotein apolipoprotein B 100 (VLDL apoB) are important determinants of plasma lipid concentrations. This study examined the effect of GH replacement therapy on VLDL apoB metabolism using a stable isotope turnover technique. VLDL apoB kinetics were determined in 14 adult patients with GH deficiency before and after 3 months GH or placebo treatment in a randomized double blind, placebo-controlled study using a primed constant [1-(13)C]leucine infusion. VLDL apoB enrichment was determined by gas chromatography-mass spectrometry. GH replacement therapy increased plasma insulin-like growth factor I concentrations 2.9 +/- 0.5-fold (P < 0.001), fasting insulin concentrations 1.8 +/- 0.6-fold (P < 0.04), and hemoglobin A1C from 5.0 +/- 0.2% to 5.3 +/- 0.2% (mean +/- SEM; P < 0.001). It decreased fat mass by 3.4 +/- 1.3 kg (P < 0.05) and increased lean body mass by 3.5 +/- 0.8 kg (P < 0.01). The total cholesterol concentration (P < 0.02), the low density lipoprotein cholesterol concentration (P < 0.02), and the VLDL cholesterol/VLDL apoB ratio (P < 0.005) decreased. GH therapy did not significantly change the VLDL apoB pool size, but increased the VLDL apoB secretion rate from 9.2 +/- 2.0 to 25.9 +/- 10.3 mg/kg x day (P < 0.01) and the MCR from 11.5 +/- 2.7 to 20.3 +/- 3.2 mL/min (P < 0.03). No significant changes were observed in the placebo group. This study suggests that GH replacement therapy improves lipid profile by increasing the removal of VLDL apoB. Although GH therapy stimulates VLDL apoB secretion, this is offset by the increase in the VLDL apoB clearance rate, which we postulate is due to its effects in up-regulating low density lipoprotein receptors and modifying VLDL composition.

Increased hepatic secretion of very-low-density-lipoprotein apolipoprotein B-100 in heterozygous familial hypercholesterolaemia: a stable isotope study.

We have measured the hepatic secretion of very-low-density-lipoprotein apolipoprotein B-100 (VLDL apo B) in 6 patients with heterozygous familial hypercholesterolaemia (FH) (4 males, 2 females, age 47.0 +/- 2.7 years (mean +/- S.E.M.), weight 71.0 +/- 5.3 kg) and 6 normocholesterolaemic subjects matched for age, weight and sex (4 males, 2 females, age 47.5 +/- 3.1 years, weight 70.0 +/- 4.4 kg) using a stable isotope method. Each subject received a primed, constant infusion of [I-13C]leucine and isotopic enrichment of VLDL apo B was determined using gas-chromatography mass-spectrometry (GCMS). Mean plasma low-density-lipoprotein (LDL) cholesterol and apo B concentrations in the FH group were more than twice that in the control group (FH, 8.5 +/- 0.5 mmol/l vs. controls, 3.3 +/- 0.2 mmol/l, P < 0.001; and FH, 2.0 +/- 0.1 g/l vs. controls, 1.0 +/- 0.04 g/l, P < 0.0001, respectively). Plasma triglyceride (TG) and high-density-lipoprotein (HDL) cholesterol concentrations were not significantly different between the two groups. Although the fractional secretion rates of VLDL apo B were similar (FH, 14.3 +/- 3.6 pools/day vs. controls, 11.6 +/- 1.7 pools/day, P = 0.53), VLDL apo B pool size and VLDL apo B absolute secretion rates (ASR) were significantly higher in the FH group (FH, 234.2 +/- 27.8 mg vs. controls, 66.3 +/- 13.5 mg, P < 0.001; and FH, 51.4 +/- 17.9 mg/kg per day vs. controls, 9.4 +/- 1.1 mg/kg per day, P < 0.02, respectively). We conclude that FH is associated with increased hepatic secretion of VLDL apo B and that this may contribute to the elevated concentration of LDL-cholesterol. The findings are also consistent with the hypothesis that in FH increased hepatic cholesterol availability (due to increased uptake of LDL-cholesterol via the receptor-independent pathway) stimulates hepatic secretion of VLDL apo B.

Prevalence of microalbuminuria, lipoprotein (a) and coronary artery disease in the lipid clinic.

AIMS: To assess the prevalence of microalbuminuria (MA) and elevated serum lipoprotein (a) (Lp (a)) concentration, and their association with coronary artery disease (CAD) and other conventional cardiovascular risk factors in non-diabetic patients attending a lipid clinic. METHODS: Clinical details were obtained from 96 consecutive non-diabetic patients from whom a fasting blood sample was taken to measure serum lipid, lipoprotein, apolipoprotein and plasma glucose, urea, and electrolyte concentrations. The urine albumin/creatinine ratio (Ua/Uc) was estimated from a random clinic sample. RESULTS: Of the patients, 26% had MA (defined as a Ua/Uc > 2.2 mg/mumol), 38% had an elevated Lp (a) concentration (defined as > 0.4 g/l), 36% were hypertensive (blood pressure > 160/95) or were taking antihypertensive medication, and 25% had established CAD defined on clinical criteria. In men the Ua/Uc ratio was highly associated with age, plasma low density lipoprotein cholesterol, and triglyceride concentrations. In women there was no association between the Ua/Uc ratio and variables examined. Lp (a) concentration was not associated with variables examined in either sex. In multiple logistic regression analysis adjusted for age and sex, serum Lp (a) concentration, diastolic blood pressure and treatment of hyperlipidaemia were highly associated with CAD. MA was not, however, associated with CAD. CONCLUSIONS: MA is common in a lipid clinic and is more likely to be found among older male patients with hyperlipidaemia. However, in contrast with Lp (a) concentrations, MA is not a risk factor for CAD in this high risk population. Lp (a) concentration may be a useful tool in the lipid clinic, but there does not seem to be a justification for measuring the Ua/Uc ratio, at least in non-diabetic subjects.

Comparison of immunoturbidimetric and Lowry methods for measuring concentration of very low density lipoprotein apolipoprotein B-100 in plasma.

To assess whether the Lowry-tetramethylurea method for measuring apolipoprotein B-100 (apo-B) in very low density lipoprotein (VLDL) could be replaced by direct assay of VLDL apo-B using a highly practicable immunological method. Seventy five fasting blood samples were collected from patients attending the lipid clinic at this hospital. Plasma was separated immediately and VLDL isolated by preparative ultracentrifugation at solution density 0.93-1.006 kg/l. Apo-B was precipitated from an aliquot of the VLDL fraction using the tetramethylurea (TMU) technique and protein mass determined by the Lowry method (LM); mean apo-B 83.02 micrograms/ml (SD 74.85). Apo-B was also measured in VLDL using direct immunoturbidimetry on the Cobas-Fara analyser; mean apo-B 82.32 micrograms/ml (SD 72.88). There was a very close correlation between methods (immunoturbidimetry = 0.94.LM + 3.95, r = 0.97, p < 0.001). The mean difference between methods (constant error) was small (0.70 microgram/ml) and not significant (p = 0.742). Random error was 13.01 micrograms/ml by analysis of variance. It is concluded that immunoturbidimetry, a more rapid and convenient test, may replace the LM and TMU techniques for measuring VLDL apo-B concentration and that this method could be applied to research studies requiring analysis of large numbers of samples.

Direct correlation between cholesterol synthesis and hepatic secretion of apolipoprotein B-100 in normolipidemic subjects.

The regulation of apolipoprotein B-100 (apo B) metabolism in man is not fully understood. In vitro studies suggest a key role for the hepatic availability of cholesterol substrate. We therefore examined whether there was a direct association between plasma mevalonic acid (MVA) concentration (an index of in vivo cholesterol synthesis) and hepatic secretion of very-low-density lipoprotein (VLDL) apo B in eight normolipidemic, healthy adult subjects. Hepatic secretion of VLDL apo B was estimated by endogenous labeling of apo B with an 8-hour primed, constant infusion of 1-13C-leucine. Isotopic enrichment of VLDL apo B was measured by gas chromatography-mass spectrometry (GCMS), from which the fractional secretion rate (FSR) was derived by a modified monoexponential function. Plasma concentration of MVA was measured by gas chromatography-electron-capture mass spectrometry in blood samples taken at 9 AM. The absolute secretion rate (ASR) of VLDL apo B (mean +/- SD) was 9.7 +/- 2.6 mg/kg/d, and MVA concentration was 5.0 +/- 2.5 ng/mL. There was a highly significant positive correlation between ASR of VLDL apoB and plasma MVA (r = .88, P = .004), which persisted after adjusting for apo E phenotype. The findings suggest that in vivo cholesterol synthesis is a determinant of hepatic secretion of apo B in normolipidemic subjects.

Long-term predictors of coronary artery disease and mortality in type 1 diabetes.

We assessed clinical and biochemical predictors of death and/or cardiovascular disease in 147 type 1 diabetes mellitus (DM) patients followed-up for 14 years. At follow-up, 28 of patients (19%) had died, and 25 patients (18%) had developed or died of coronary artery disease (CAD). At baseline, those who died had significantly higher serum creatinine (p=0.001) and urine albumin/creatinine ratio (p=0.016), greater prevalence of retinopathy (p=0.006), lower serum apolipoprotein A1 (p=0.046), and lower daily insulin dose (p=0.024) than those who survived. CAD patients had a longer duration of diabetes (p<0.001), were older at the onset of diabetes and at presentation (p=0.001), and had higher prevalences of retinopathy (p=0.005) and neuropathy (p=0.016). The CAD group also had higher baseline serum creatinine (p=0.02), lower HDL cholesterol (p=0.004) and apolipoprotein A1 (p=0.007) and higher LDL cholesterol (p=0.028) and apolipoprotein B concentrations (p=0.027). Under logistic regression analysis (adjusted for age and sex), baseline urine albumin/creatinine ratio (p=0.003), presence of retinopathy (p=0.004), serum creatinine (p=0.028), and serum urea (p=0.034) were the most powerful predictors of mortality, while duration of diabetes (p<0.0001), baseline HDL cholesterol (p=0.012), serum creatinine (p=0.02), apolipoprotein B (p=0.038), LDL cholesterol (p=0.039), and systolic blood pressure (p=0.055) were the strongest predictors of CAD. These findings emphasize the role of abnormal lipoprotein metabolism in the development of CAD in type 1 DM. Indicators of renal impairment and the presence of retinopathy seem to be of greater importance in predicting overall mortality.

Delayed pathology of the appendiceal stump: a case report of stump appendicitis and review.

A case of right lower quadrant pain in a 53-year-old postmenopausal female who underwent appendectomy 21 years previously is presented. Recurrent appendicitis with rupture was noted in the appendiceal stump on exploratory celiotomy after diagnosis by computed tomography scan. Although rare, pathology of the appendiceal stump, whether inverted or not, is a real entity that can be encountered on laparotomy. Malignancy and hemorrhage can also occur in the appendiceal remnant, but the large number of disorders that can cause acute right lower quadrant abdominal pain makes appendiceal stump pathology extremely difficult to detect preoperatively. Because of the extensive differential diagnosis, timely operative intervention for clinical peritonitis in this region should not be delayed.