A Long-Period, Violently Variable X-ray Source in a Young Supernova Remnant

Observations with the Newton X-ray Multimirror Mission satellite show a strong periodic modulation at 6.67 +/- 0.03 hours of the x-ray source at the center of the 2000-year-old supernova remnant RCW 103. No fast pulsations are visible. If genetically tied to the supernova remnant, the source could either be an x-ray binary, composed of a compact object and a low-mass star in an eccentric orbit, or an isolated neutron star. In the latter case, the combination of its age and period would indicate that it is a peculiar magnetar, dramatically slowed down, possibly by a supernova debris disc. Both scenarios require nonstandard assumptions about the formation and evolution of compact objects in supernova explosions.

Educating diabetic patients about insulin use: changes over time in certainty and correctness of knowledge

AIM

Diabetic patients should understand their disease correctly and be sure of what they know, but certainty is rarely considered by educators. Furthermore little is known about how certainty changes with time after an educational intervention. To clarify this, in 38 patients with type 1 diabetes (0.3-36 years duration) we analysed the effect of a course on insulin use by administering a questionnaire before the course, after the course and 1 and 3 years later.

METHODS

Answers, accompanied by a subjective estimate of the degree of certainty, were assigned to mastered knowledge (certainty>or=90%, correctness>or=90%), hazardous knowledge (certainty>or=90%, correctness<or=50%), uncertain knowledge (certainty<or=50%, correctness>or=90%) and residual knowledge (total-[mastered+hazardous+uncertain]). Answers were then counted and changes in distribution among areas were analysed by the chi2 test. We also followed the fate of wrong answers.

RESULTS

The course increased mastered knowledge, while other types of knowledge decreased. With time mastered knowledge decreased, patients losing both correctness and certainty. The loss affected declarative knowledge, based purely on theory, more than procedural knowledge, which concerns the way things are done. Wrong answers, mostly given with high degree of certainty, were heterogeneous since some became correct after the course, some remained wrong, some became wrong after the course, some became mistaken after having been corrected earlier.

CONCLUSIONS

The analysis of certainty helps in evaluating patient's knowledge; programmes tending to improve procedural knowledge are more likely to have long lasting effects; wrong answers need to be considered on a individual basis.

Lower within-subject variability of fasting blood glucose and reduced weight gain with insulin detemir compared to NPH insulin in patients with type 2 diabetes

AIM

The aim of this study was to compare the efficacy and safety of a basal-bolus insulin regimen comprising either insulin detemir or neural protamine hagedorn (NPH) insulin in combination with mealtime insulin aspart in patients with type 2 diabetes.

METHODS

This was a 26-week, multinational, open-label, parallel group trial with 505 patients with type 2 diabetes (mean age, 60.4 +/- 8.6 years; mean BMI, 30.4 +/- 5.3 kg/m(2); mean HbA(1c), 7.9 +/- 1.3%). Patients, randomized 2:1 to insulin detemir or NPH insulin, received basal insulin either once or twice daily according to their pretrial insulin treatment and insulin aspart at mealtimes.

RESULTS

After 26 weeks of treatment, significant reductions in HbA(1c) were observed for insulin detemir (0.2%-points, p = 0.004) and NPH insulin (0.4%-points; p = 0.0001); HbA(1c) levels were comparable at study end (insulin detemir, 7.6%; NPH insulin, 7.5%). The number of basal insulin injections administered per day had no effect on HbA(1c) levels (p = 0.50). Nine-point self-measured blood glucose (SMBG) profiles were similar for the two treatment groups (p = 0.58), as were reductions in fasting plasma glucose (FPG) (insulin detemir, 0.5 mmol/l; NPH insulin, 0.6 mmol/l). At study end, FPG concentrations were similar for the two treatment groups (p = 0.66). By contrast, within-subject day-to-day variation in fasting SMBG was significantly lower with insulin detemir (p = 0.021). Moreover, patients receiving insulin detemir gained significantly less body weight than those who were administered NPH insulin (1.0 and 1.8 kg, respectively, p = 0.017). The frequency of adverse events and the risk of hypoglycaemia were comparable for the two treatment groups.

CONCLUSIONS

Patients with type 2 diabetes, treated for 26 weeks with insulin detemir plus insulin aspart at mealtimes, experienced comparable glycaemic control but significantly lower within-subject variability and less weight gain compared to patients treated with NPH insulin and insulin aspart. Insulin detemir was well tolerated and had a similar safety profile to NPH insulin.

Effect of sodium intake on blood pressure and albuminuria in Type 2 diabetic patients: the role of insulin resistance

AIMS/HYPOTHESIS

This study was done to measure the effect of Na+ intake on blood pressure and albuminuria, in relation with insulin sensitivity and kidney haemodynamics, in Type 2 diabetic patients with and without microalbuminuria.

METHODS

Type 2 diabetic patients, 20 with microalbuminuria, 21 without, spent two consecutive 7-day periods, one on a high (250 mmol), the other on a low-Na+ (20 mmol) diet. Body weight, 24-h blood pressure and albuminuria were measured at the end of each period. At the end of high-Na+ diet insulin sensitivity (euglycaemic insulin clamp; 2 mU.kg(-1).min(-1)) and kidney haemodynamics were measured in nine patients from each group.

RESULTS

Switching from low to high-Na+ diet resulted in an increase in blood pressure (7.4+/-4.7 mmHg; p<0.001), body weight (1.9+/-0.4 kg; p<0.05) and albuminuria [from 80 (31-183) microg/min to 101 (27-965) microg/min; p<0.01) in patients with microalbuminuria. No changes occurred in patients without microalbuminuria. Patients with microalbuminuria also had greater intraglomerular pressure (44+/-1 mmHg vs 36+/-1; p<0.001), calculated from glomerular filtration rate, renal plasma flow, plasma protein concentration and the relationship between pressure and natriuresis. In these patients insulin sensitivity was lower (5.16+/-49 vs 7.36+/-0.63 mg.kg(-1).min(-1); p=0.007). Urinary albumin excretion (r=0.40; p=0.009) and insulin sensitivity (r=-0.59; p=0.01) were correlated with intraglomerular pressure.

CONCLUSION/INTERPRETATION

High salt intake increases blood pressure and albuminuria in Type 2 diabetic patients with microalbuminuria. These responses are associated with insulin resistance and increased glomerular pressure. Insulin resistance could contribute to greater salt sensitivity, increased glomerular pressure and albuminuria.

Role of anti-granulocyte Fab??? fragment antibody scintigraphy (LeukoScan) in evaluating bone infection: acquisition protocol, interpretation criteria and clinical results

Scintigraphy using anti-granulocyte Fab' fragment (LeukoScan) was performed in a series of 220 consecutive patients with suspected bone infection referred to our centre between September 1999 and June 2002. Two protocols were compared for interpreting scans: (1) evaluation of early 4 h imaging alone (protocol A), and (2) evaluation both of early and delayed 24 h imaging (protocol B). Protocol A and protocol B showed equal values of sensitivity (91.9% in patients with diabetic foot and 84.2% in patients with joint prosthesis/peripheral bone implants). Conversely, specificity was higher adopting protocol B than protocol A: 87.5% vs 75.0% in patients with diabetic foot, and 85.7% vs 76.2% in patients with joint prosthesis/peripheral bone implants, respectively. In particular, an improvement in specificity using protocol B was found in those patients with infection and with only a mild LeukoScan uptake in the early 4 h imaging: in these patients an increasing uptake intensity pattern observed in the delayed 24 h imaging was indicative of infection while a decreasing pattern suggested a negative result. Instead, the evidence of a high uptake intensity in the early LeukoScan imaging was a strong indicator of infection and delayed imaging in these cases did not further improve specificity. In conclusion, in our experience, LeukoScan showed high sensitivity in diagnosing bone infection in patients with diabetic foot and joint prosthesis or other peripheral bone implants. Moreover, in patients with an early high LeukoScan uptake intensity further delayed images appears unnecessary for the purpose of diagnosing infection. In contrast in patients with an early mild LeukoScan uptake intensity only, delayed imaging appears to be recommendable for improving specificity.

Moderate alcohol consumption, glucose metabolism and lipolysis: the effect on adiponectin and tumor necrosis factor alpha

Moderate alcohol consumption has a cardioprotective effect on coronary artery disease. Among the beneficial effects of alcohol, a suppression of the plasma free fatty acid (FFA) concentration has been shown but the mechanism which accounts for this action is not clear. We assessed whether moderate alcohol intake affects plasma adiponectin levels and tumor necrosis factor (TNF)-alpha, two regulators of lipolysis. Oral glucose tolerance tests were performed twice on 22 volunteers: "the alcohol study" and "control study". In the former, red wine was sipped to maintain steady state alcohol concentration. Samples for plasma glucose, insulin, FFA, adiponectin, and TNF-alpha concentrations were obtained. In the latter, tap water was sipped. Insulin action has been assessed by the Oral Glucose Insulin Sensitivity (OGIS) Model. The mean blood alcohol concentration was 5+/-2 mg/dl. No differences were observed between the two studies in the OGIS (406+/-19 ml x min(-1) x m(-2) with alcohol and 402+/-20 without, respectively). Baseline FFA levels were lower in the alcohol study; however, post-glucose inhibition was comparable. No differences in the TNF-alpha and adiponectin responses were observed. A significant correlation was observed between the OGIS index and the fasting adiponectin level (r=0.589, p<0.0001). Moderate red wine intake improves post-glucose FFA profiles but does not modify the plasma concentrations of both TNF-alpha and of adiponectin concentrations: the latter is significantly and positively associated to the insulin action. Further studies are needed to clarify the antilipolytic effect of moderate alcohol intake.

Visceral obesity is characterized by impaired nitric oxide-independent vasodilation

BACKGROUND

Endothelial dysfunction has been described in obesity. This study examines the impact of visceral obesity on nitric oxide-independent relaxation in the human forearm.

METHODS AND RESULTS

In ten viscerally obese and ten matched controls forearm blood flow (FBF) was measured by venous occlusion plethysmography during intrabrachial infusion of: (1) sodium nitroprusside; (2) bradykinin, before and after inhibition of vasoactive prostaglandins and nitric oxide; (3) potassium; (4) ouabain (Na(+)/K(+)ATPase inhibitor) alone or (5) in combination with BaCl(2)(K(IR)inhibitor). Baseline FBF and endothelium-independent vasodilatation were similar in the two groups. In obese patients, bradykinin-induced increase of FBF was significantly less than in controls (P<0.01). Irrespective of prostaglandins and nitric oxide inhibition, bradykinin response was lower in the viscerally obese. Intrabrachial potassium determined a significantly blunted response (P<0.05). Ouabain caused a similar, moderate decrease in basal FBF in the two groups; the coinfusion of BaCl(2)caused a more intense decline in FBF which was significantly relevant in obese (-24+/-5%, P<0.01).

CONCLUSIONS

In obese patients there is a blunted nitric oxide-independent relaxation determined by a decreased response of inwardly rectifying potassium channels.

In situ protein Kinase C activity is increased in cultured fibroblasts from Type 1 diabetic patients with nephropathy

AIMS/HYPOTHESIS

To verify whether individual susceptibility to diabetic nephropathy resides in an intrinsic difference in Protein Kinase C (PKC) activity.

METHODS

We compared the effect of different glucose concentrations on PKC activity, PKC isoform expression and diacylglycerol (DAG) content in cultured fibroblasts from 14 Type 1 diabetic patients who developed nephropathy with those in cells from 14 patients without nephropathy. We recruited 14 normal subjects as control patients. Forearm skin fibroblasts were cultured in either normal (5 mmol/l) or high (20 mmol/l) glucose concentrations.

RESULTS

In normal glucose, in situ PKC activity was higher in Type 1 patients with nephropathy (10.1+/-1.4 pmol/min/mg protein; p<0.01) than in those without (6.8+/-0.8) and the normal control subjects (6.3+/-0.5). This difference was due to increased concentrations of PKCalpha isoform in the membrane fraction of fibroblasts from patients with nephropathy. DAG content was also higher in cells from Type 1 patients with nephropathy. Incubation in high glucose concentration caused a further increase in PKC activity and DAG content in quiescent fibroblasts from patients with diabetic nephropathy, with no significant changes in cells from diabetic patients without nephropathy and normal control subjects.

CONCLUSION/INTERPRETATION

Differences in PKC activation could contribute to the individual susceptibility to renal damage in Type 1 diabetic patients.

Diabetic ketosis activates lymphomonocyte-inducible nitric oxide synthase

AIMS

Inappropriate production of nitric oxide (NO) may be responsible for the haemodynamic disturbances of diabetic ketoacidosis. We investigated whether this metabolic condition is associated with increased plasma nitrate (the stable oxidation product of NO) levels and NO synthase gene expression in lymphomonocytes.

RESEARCH DESIGN AND METHODS

Plasma nitrate concentrations, lymphomonocyte-inducible nitric oxide synthase (iNOS) gene expression, tumour necrosis factor-alpha (TNF-alpha) and soluble thrombomodulin were measured in 11 Type 1 diabetic patients at baseline, during mild ketosis and after euglycaemia was re-established.

RESULTS

During diabetic ketosis plasma nitrate concentrations were higher (18 (16-21) vs. 9 (7-11) micro mol/l; (95% lower-upper confidence interval) P < 0.05) than at baseline. At baseline lymphomonocyte iNOS mRNA expression and iNOS protein levels were undetectable, but in ketosis both were increased (both at P < 0.0001). After recovery from ketosis, NO3 concentration, iNOS mRNA, and iNOS expression (270 +/- 36%, mean +/- sd) decreased but not significantly. No significant changes were observed in either TNF-alpha or soluble thrombomodulin levels between the three conditions.

CONCLUSIONS

Diabetic ketosis is associated with increased nitrate levels and the activation of iNOS expression in circulating lymphomonocytes, but it does not affect either the proinflammatory cytokine TNF-alpha or a marker of endothelial dysfunction such as thrombomodulin. Our data support the hypothesis that, during diabetic ketosis, alterations in NO homeostasis are present in circulating lymphomonocytes.

Glycaemic control and microvascular complications in a large cohort of Italian Type 1 diabetic out-patients

The purpose of this cross-sectional study was to evaluate the degree of metabolic control, the prevalence of microvascular complications (nephropathy, retinopathy, and peripheral neuropathy) and their association with risk factors for cardiovascular diseases in all adult Type 1 diabetic out-patients attending 2 Diabetes Clinics of Northern Italy over 12 months. A total of 458 patients (mean age 37 +/- 12 yr, duration of diabetes 15.3 +/- 10.6 yr, BMI 23.2 +/- 3.1 kg/m2) were studied. Clinical characteristics and microvascular complications were evaluated. The proportion of patients with a good glycaemic control (HbA1c < 7%) was 14.7%. Nephropathy was observed in 24.4%, retinopathy in 41%, peripheral neuropathy in 23.7%. The prevalence of hypertension was 30.3%. Microvascular complications were associated with age, duration of diabetes, systolic blood pressure, creatinine, triglycerides and cholesterol plasma levels. Mean HbA1c was 8.5 +/- 1.6. Patients with HbA1c levels < 7% presented a lower prevalence of complications and lower levels of cholesterol, triglycerides, systolic blood pressure than patients with HbA1c > 9%. Our study indicates that an acceptable metabolic control is achieved in a too low proportion of Type 1 diabetic patients, even under multiple insulin injections. The association of poor metabolic control and microalbuminuria identifies a group of patients at higher risk of diabetic complications.

Continuous subcutaneous insulin infusion (CSII) in the Veneto region: efficacy, acceptability and quality of life

AIM

To study the effect of continuous subcutaneous insulin infusion (CSII) on metabolic control and well-being in patients with Type 1 diabetes.

METHODS

Efficacy, safety and interference with everyday life associated with CSII were studied retrospectively in 138 diabetic patients from the Veneto region treated for 7.4 +/- 0.4 years.

RESULTS

Glycosylated haemoglobin decreased during the first year of CSII from 9.3 +/- 0.2% to 7.9 +/- 0.1% (P < 0.0001), and then remained unchanged. Serious hypoglycaemia decreased from 0.31 +/- 0.07/year to 0.09 +/- 0.02/year (P < 0.003), as did ketoacidosis (from 0.41 +/- 0.12/year to 0.11 +/- 0.03/year, P < 0.013). During the first year of therapy daily insulin requirement decreased from 49 +/- 1 to 42 +/- 2 U/day (P < 0.0001) and did not change thereafter. The number of out-patient consultations and hospital admissions per year also decreased significantly. CSII was associated with a progressive increase of body weight (P < 0.05) and with 0.2 +/- 0.04 infections/patient per year at the infusion site. Infection was rated as mild in 72%, moderate in 18%, severe in 10%. Patients reported that CSII improved metabolic control (71%), sense of well-being (41%), and allowed more freedom (40%). Quality of life, assessed using the DQOL, after 7 years of CSII was rated as good by patients (score of 73.0 +/- 1.8 on a scale from 0 to 100).

CONCLUSIONS

This retrospective analysis suggests that CSII improves metabolic control in Type 1 diabetic patients, reduces hypoglycaemic and ketoacidotic events, is well accepted, allows a good quality of life and decreases out-patient consultations and hospital admissions.

Insulin infusion normalizes fasting and post-prandial albumin and fibrinogen synthesis in Type 1 diabetes mellitus

AIMS

The effect of metabolic control on hepatic synthesis of plasma proteins in Type 1 diabetes mellitus (T1DM), in the post-absorptive and post-prandial state, is not known.

METHODS

We measured fractional synthetic rates (FSR) of albumin and fibrinogen in six insulin-infused T1DM patients and in five to nine control subjects, before and for approx. 4 h after a mixed liquid meal. Phenylalanine tracer precursor/product relationships and steady-state conditions were used. In the post-absorptive state, patients were studied in near euglycaemic conditions after an overnight intravenous insulin infusion. During the meal (approx. 11 kcal/kg), the insulin infusion rate was increased to maintain plasma glucose concentrations below approx. 10 mmol/l.

RESULTS

Post-absorptive FSR of albumin (5.7 +/- 0.6%/day) and fibrinogen (11.3 +/- 0.6%/day) in T1DM were similar to control values (6.4 +/- 0.9 and 13.1 +/- 1.1, respectively). After the meal, albumin FSR increased (P = 0.0032 by anova) in both groups (T1DM, to 14.4 +/- 2.7%/day; controls, to 18.2 +/- 3.7%/day). Fibrinogen FSR also increased (P = 0.0048 by anova) in both the T1DM (to 18.2 +/- 2.6) and the control subjects (to 27.3 +/- 6.2). There was no difference between T1DM and control subjects in the post-prandial FSR of both proteins.

CONCLUSIONS

Albumin and fibrinogen FSR in T1DM can be maintained within near-normal ranges by insulin infusion under post-absorptive and post-prandial conditions.

Teaching and training programme on carbohydrate counting in Type 1 diabetic patients

Carbohydrates (CHO) are a major determinant of post-prandial blood glucose in the diet of people with Type 1 diabetes mellitus, but patients frequently fail to evaluate CHO food content. Poor education is thought to contribute heavily to this failure. Our aim was to plan and evaluate a simple educational program to improve dietary knowledge and teach how to count CHO in Type 1 diabetic subjects. Forty-eight patients (age 27+/-1 yr, diabetes duration 11+/-1 yr, HbA1c 9%) attended 4 interactive meetings held at monthly intervals. The targets of the course were: 1) to identify sources of CHO, fats and proteins; 2) to count CHO and to split them among meals; 3) to assume CHO-rich foods without changing daily calorie or carbohydrate intake; 4) to modify the diet so as to correct hypoglycaemic events. To evaluate the effect of the course, patients completed a 7-day food record and answered a questionnaire covering the targets of the course at baseline, at the end of the course and 7 months later. After the course dietary knowledge improved significantly. The number of patients who weighed foods, estimated CHO food content and correctly distributed CHO among meals also increased. After the course patients reacted better when faced with hypoglycaemia. The knowledge acquired persisted 7 months after the end of the course. Therefore, we conclude that a simple teaching program can improve diet knowledge in Type 1 diabetics and establish a sustained habit of counting CHO.

Gemfibrozil improves insulin sensitivity and flow-mediated vasodilatation in type 2 diabetic patients

BACKGROUND

Endothelial dysfunction is an early feature of atherosclerosis. The relationship between insulin action and hypertriglyceridaemia on endothelial function is still debated.

MATERIALS AND METHODS

This study was designed to determine the effect of a 3 month treatment with Gemfibrozil (GF) on flow-mediated vasodilatation and insulin sensitivity. Ten type 2 diabetic patients were randomised in crossover, double blind fashion, either to GF, 600 mg b.i.d. or placebo, for 12 weeks. Lipid profile, low-density lipoprotein (LDL) distribution and flotation properties, insulin action and flow-mediated vasodilatation (FMD) by brachial artery ultrasound, were assessed.

RESULTS

GF decreased serum triglyceride (TG) concentration with an absolute difference of 1.79 +/- 1.28 mmol L-1 (P < 0.0016) between active treatment and placebo, and significantly increased serum high-density lipoprotein (HDL) cholesterol (P = 0.0233). No differences were observed in total, intermediate-density lipoproteins (IDL), LDL cholesterol concentration and LDL peak buoyancy between treatments. GF also improved SI, an index of insulin action (P = 0.005). The FMD was 7 +/- 3% in the baseline condition, 7 +/- 2% during placebo and 14 +/- 3% after GF (P < 0.006).

CONCLUSIONS

GF treatment improves both insulin action and flow-mediated vasodilatation in type 2 diabetic patients. The reduction of TG concentration allows the simultaneous correction of two important components of the metabolic syndrome.

The importance of first-phase insulin secretion: implications for the therapy of type 2 diabetes mellitus

Type 2 diabetes is a heterogeneous disorder characterized by defects in insulin secretion and action. Insulin resistance is a key feature of type 2 diabetes. However, insulin resistance alone does not appear to be sufficient to cause diabetes. Longitudinal studies have shown that the development of overt hyperglycemia is associated with a decline in beta-cell secretion. In patients with impaired glucose tolerance or in the early stages of type 2 diabetes, first-phase insulin release is almost invariably lost despite the enhancement of second-phase secretion. Both animal and human studies support the critical physiologic role of the first-phase of insulin secretion in the maintenance of postmeal glucose homeostasis. This effect is primarily mediated at the level of the liver, allowing prompt inhibition of endogenous glucose production (EGP) and thereby restraining the mealtime rise in plasma glucose. In type 2 diabetes, the loss of the early surge of insulin release is a precocious and quite common defect that plays a pathogenic role in postmeal hyperglycemia and one that may require specific therapeutic intervention. This becomes even more apparent if the negative impact of prandial glucose spikes is taken into consideration. Epidemiological evidence exists to indicate that 2-h postload plasma glucose levels are strongly associated with all-cause and cardiovascular mortality relative risk. Indeed the acute elevation of plasma glucose concentration triggers an array of tissue responses that may contribute to the development of diabetic complications. Considering that type 2 diabetes begins with meal-related hyperglycemia in many patients, it becomes apparent that normalization of postmeal plasma glucose levels should be the target for rational therapy and the goal in the early stages of the disease. If a primary goal of diabetes therapy is control of postmeal glucose excursion, then the regulation of glucose absorption from the gut and entry into the circulation is an important mechanism to consider. The restoration of the rapid increase in plasma insulin concentration may be quite an efficient therapeutic approach.

Combination of continuous subcutaneous infusion of insulin and octreotide in Type 1 diabetic patients

The effect of 7 day continuous subcutaneous infusion of octreotide (200 microg day(-1)) was evaluated in seven insulin-pump treated Type 1 diabetic patients (age 43+/-1.5 year; BMI 25.1+/-0.7 kg m(-2); HbA(1c) 7.4+/-0.3%). A 24-h metabolic and hormonal profile, and a euglycaemic hyperinsulinaemic clamp (0.25, 0.5, 1.0 mg kg(-1) min(-1)), with [3H]glucose infusion and indirect calorimetry, were performed before and after a 7-day octreotide infusion. Mean 24-h plasma glucose was similar before and after octreotide (9.7+/-0.8 vs. 9.1+/-1.0 mmol l(-1)) but insulin requirement dropped by 45% (49+/-4 vs. 27+/-2 U day(-1); P<0.01). Both 24-h plasma hGH and glucagon were suppressed by octreotide (1.85+/-0.35 vs. 0.52+/-0.04 microg l(-1), and 117+/-23 vs. 102+/-14 ng l(-1), respectively). Glucose utilisation increased after octreotide (insulin 0.5 mU kg(-1) min(-1) clamp 3.09+/-0.23 vs. 4.19+/-0.19 mg kg(-1) min(-1); 1 mU kg(-1) min(-1) clamp 5.64+/-0.61 vs. 7.93+/-0.57 mg kg(-1) min(-1); both P<0.05) and endogenous glucose production was similarly suppressed. Glucose oxidation was not affected by octreotide, while the improvement in glucose storage (insulin 1.0 mU kg(-1) min(-1) clamp 3.89+/-0.60 vs. 5.64+/-0.67 mg kg(-1) min(-1), P<0.05) entirely accounted for the increase in glucose disposal. Endogenous glucose production was more effectively suppressed at the two lower insulin infusion rates (P>0.05). Energy expenditure declined after octreotide. Continuous subcutaneous octreotide infusion suppresses counterregulatory hormones, increases insulin-mediated glucose metabolism by enhancing glucose storage, and reduces energy expenditure. These results support a role for counterregulatory hormones in the genesis of insulin resistance and the catabolic state of Type 1 diabetes.

Serum protein profiles of patients with pancreatic cancer and chronic pancreatitis: searching for a diagnostic protein pattern

In this study, 13 sera from patients with pancreatic cancer, 9 from chronic pancreatitis and 10 from healthy subjects were analyzed by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The MALDI mass spectra revealed the presence of several low molecular weight peptides, among which some were detected only in the sera from both pathological conditions. On the other hand many peptides were observed only in control sera, and were absent in the sera from the two diseases. Therefore, MALDI analysis of the low molecular weight fraction (<10 000 Da) of sera from patients with pancreatic diseases enabled us to identify the presence of some disease-related signals and also some signals characteristic of normal subjects.

Comparison of capillary electrophoresis with HPLC for diagnosis of factitious hypoglycemia

BACKGROUND

The diagnosis of "factitious hypoglycemia" is essentially based on the disclosure of hypoglycemic agents in blood or urine. The aim of this study was to evaluate the performance of capillary electrophoresis (CE) as a quantitative method for determination of chlorpropamide, tolbutamide, glipizide, gliclazide, and glibenclamide in serum.

METHODS

Serum samples (1 mL), with internal standard added, were purified by solid-phase extraction on OASIS(TM) HLB cartridges (Waters), dried under reduced pressure, and reconstituted with 30-60 microL of acetonitrile:H(2)O. Analysis was carried out by micellar electrokinetic capillary chromatography in 5 mmol/L borate, 5 mmol/L phosphate, 75 mmol/L sodium cholate, pH 8.5, containing 25 mL/L methanol. Separation was accomplished in a 20 cm x 50 microm (i.d.) silica capillary at 25 degrees C and a constant voltage of +10 kV. Pharmacokinetics of gliclazide (80-mg tablet) in a diabetic patient were assayed by both HPLC and CE. Two hypoglycemic patients positive by HPLC analysis for unreported gliclazide and tolbutamide overdose were also screened by CE.

RESULTS

Separation of six drugs (including the internal standard) was accomplished in 5 min plus 5 min rinsing. The between-day CV of the ratio of the areas of the sulfonylurea drugs to internal standard was <1% (n = 10). Linearity (r(2) > or =0.998) and recovery (> or =80%) were good for all sulfonylurea drugs tested. Pharmacokinetic curves for gliclazide by CE and HPLC were superimposable. CE analysis confirmed the HPLC diagnosis of surreptitious abuse of gliclazide and tolbutamide.

CONCLUSION

CE is a useful tool in the clinical chemistry and toxicology laboratory for drug monitoring and pharmacokinetic investigations.

Increased fibrinogen production in type 2 diabetic patients without detectable vascular complications: correlation with plasma glucagon concentrations

Fibrinogen is a strong cardiovascular risk factor in the general population, and increased fibrinogen plasma concentrations have been reported in type 2 diabetic patients. However, the mechanisms leading to hyperfibrinogenemia in type 2 diabetes are not known. It is also not known whether possible alterations of fibrinogen turnover may precede clinical diabetic micro- and macrovascular complications and therefore potentially contribute to their onset. To address these questions, fibrinogen production was determined in six male type 2 diabetic patients without detectable micro- and macrovascular complications (age, 45 +/- 4 yr; body mass index, 27 +/- 0.9 kg/m2) and in seven nondiabetic matched controls using leucine isotope precursor-product relationships. Plasma glucose (P < 0.001), insulin (P < 0.05), and glucagon concentrations (P < 0.01) were increased in the patients. Diabetic patients also had increased plasma fibrinogen concentration (+ approximately 50%; P < 0.01) and pool (+ approximately 40%; P < 0.01) as well as fractional (+ approximately 35%; P = 0.08) and absolute (+ approximately 100%; P < 0.01) synthetic rates. The plasma glucagon concentration was positively related (P < 0.005 or less) to the fibrinogen concentration as well as to fractional and absolute synthetic rates. Thus, fibrinogen production is markedly enhanced, and this alteration is likely to determine the observed hyperfibrinogenemia in type 2 diabetic patients. Hyperglucagonemia may contribute to the increased fibrinogen production. These findings in normoalbuminuric patients without clinical complications support the hypothesis that increased fibrinogen production and plasma concentrations may precede and possibly contribute to the onset of clinical cardiovascular complications in type 2 diabetes.

Brain function rescue effect of lactate following hypoglycaemia is not an adaptation process in both normal and type I diabetic subjects

AIMS/HYPOTHESIS

We have previously shown that lactate protects brain function during insulin-induced hypoglycaemia. An adaptation process could, however, not be excluded because the blood lactate increase preceded hypoglycaemia.

METHODS

We studied seven healthy volunteers and seven patients with Type I (insulin-dependent) diabetes mellitus with a hyperinsulinaemic (1.5 mU.kg-1.min-1) stepwise hypoglycaemic clamp (4.8 to 3.6, 3.0 and 2.8 mmol/l) with and without Na-lactate infusion (30 mumol.kg-1.min-1) given after initiation of hypoglycaemic symptoms.

RESULTS

The glucose threshold for epinephrine response was similar (control subjects 3.2 +/- 0.1 vs 3.2 +/- 0.1, diabetic patients = 3.5 +/- 0.1 vs 3.5 +/- 0.1 mmol/l) in both studies. The magnitude of the response was, however, blunted by lactate infusion (AUC; control subjects 65 +/- 28 vs 314 +/- 55 nmol/l/180 min, zenith = 2.6 +/- 0.5 vs 4.8 +/- 0.7 nmol/l, p < 0.05; diabetic patients = 102 +/- 14 vs 205 +/- 40 nmol/l/180 min, zenith = 1.4 +/- 0.4 vs 3.2 +/- 0.3 nmol/l, p < 0.01). The glucose threshold for symptoms was also similar (C = autonomic 3.0 +/- 0.1 vs 3.0 +/- 0.1, neuroglycopenic = 2.8 +/- 0.1 vs 2.9 +/- 0.1 mmol/l, D = autonomic 3.2 +/- 0.1 vs 3.2 +/- 0.1, neuroglycopenic 3.1 +/- 0.1 vs 3.2 +/- 0.1 mmol/l) but peak responses were significantly attenuated by lactate (score at 160 min C = 2.6 +/- 1 vs 8.8 +/- 1, and 0.4 +/- 0.4 vs 4.8 +/- 1, respectively; p = 0.02-0.01, D = 1.3 +/- 0.5 vs 6.3 +/- 1.7, and 2.3 +/- 0.6 vs 5.7 +/- 1.1 p = 0.07-0.02). Cognitive function deteriorated in both studies at similar glucose thresholds (C = 3.1 +/- 0.1 vs 3.0 +/- 0.1, D = 3.2 +/- 0.1 vs 3.3 +/- 0.2 mmol/l). Although in normal subjects a much smaller impairment was observed with lactate infusion (delta four-choice reaction time at 160 min = 22 +/- 12 vs 77 +/- 31 ms; p = 0.02), in Type I diabetic patients lactate infusion was associated with an improvement in cognitive dysfunction (0.2 +/- 0.4 vs -38 +/- 0.2 delta ms, p = 0.0001).

CONCLUSION/INTERPRETATION

A blood lactate increase after the development of hypoglycaemic symptoms reduces counterregulatory and symptomatic responses to insulin-induced hypoglycaemia and favours brain function rescue both in normal and diabetic subjects. These findings confirm that lactate is an alternative substrate to glucose for cerebral metabolism under hypoglycaemic conditions.

Left ventricular mass in type 2 diabetes mellitus. A study employing a simple ECG index: the Cornell voltage

Both type 2 diabetes mellitus (DM2) and left ventricular hypertrophy are associated with an increased risk of cardiovascular diseases (CVD). A strong association between hyperinsulinemia, which is the hallmark of DM2 and of insulin resistance syndrome (a cohort of metabolic abnormalities such as DM2, dyslipidemia, hyperuricemia, obesity, hypertension, hyperfibrinogenemia), and left ventricular (LV) hypertrophy was found in several studies. We studied 140 consecutive (both normo- and hypertensive) DM2 patients to determine a possible link between metabolic features and the degree of LV mass, calculated by the ECG method of Cornell voltage. The Cornell voltage value was 12.9+/-0.5 mm in the DM2 population as a whole, and 13.6+/-0.7 vs 11.7+/-0.9 mm (p=NS) in hypertensive and normotensive DM2 subgroups, respectively. Among all the metabolic parameters taken into account, the multivariate analysis shows that the fasting plasma insulin level is the strongest independent predictor of LV mass, both in the whole population (p=0.0005) and in the normo (p=0.0460) and hypertensive DM2 (p=0.0184) subgroups.

Plasma free fatty acids and endothelium-dependent vasodilation: effect of chain-length and cyclooxygenase inhibition

Free fatty acids (FFA) are known to interfere with glucose metabolism. Moreover, it has been shown that they are able to impair the endothelium-dependent vasodilation. Therefore, we sought to determine whether their negative effect on endothelial function depends on their chain length or on their ability to modify PG production. Fourteen normal volunteers were studied under baseline conditions and then randomly allocated to two of the following four studies: 1) long chain triglyceride (LCT) emulsion and heparin infusion (n = 7), 2) infusion of an emulsion containing 56% medium chain triglycerides (MCT) and 44% LCT plus heparin (n = 7), 3) infusion of LCT and heparin preceded by an i.v. bolus of 900 mg lysine-salicylate (ASA; n = 7), and 4) after an i.v. bolus of ASA (n = 7). Basal forearm blood flow (FBF), endothelium-dependent vasodilation in response to intraarterial acetylcholine (Ach), and endothelium-independent vasodilation in response to intraarterial nitroprusside were assessed by venous occlusion plethysmography. Both LCT and MCT infusions significantly increased basal FBF from 1.58 +/- 0.35 to 2.60 +/- 0.76 and 2.28 +/- 0.56 mL/min 100 mL tissue, respectively (both P < 0.05). This increase was also observed for LCT plus heparin, but not after ASA alone. The percent increase in FBF during Ach was lowered during both LCT (252 +/- 34% of the ratio infused/control arm at maximal Ach dose) and MCT (255 +/- 41%) compared to the baseline conditions (436 +/- 44%; both P < 0.05). The response to Ach was also lower during LCT plus ASA, whereas it was similar to baseline with ASA alone. No differences were observed in the response to nitroprusside among the experimental conditions. In conclusion, 1) the effect of FFA on endothelium-dependent vasodilation is independent of their chain length; 2) both LCT and MCT increase baseline FBF, independently from cyclooxygenase inhibition; and 3) acute ASA administration does not affect endothelium-dependent vasodilation. The FFA effect on the endothelial response to Ach may contribute to altered endothelial function and, hence, to the development and progression of atherosclerotic cardiovascular disease.

Mechanisms of acute and chronic hypoglycemic action of gliclazide

An extrapancreatic effect of sulfonylureas has been postulated. However, in vivo results have been disputed because the amelioration of insulin action that follows sulfonylurea may represent the relief from glucose toxicity rather than a direct effect of the drug. Therefore, we studied the hypoglycemic action of gliclazide acutely and after 2 months of therapy in seven type 2 diabetic patients. All patients received a 240-minute i.v. glucose infusion with [3-3H]glucose. In a random order, 160 mg gliclazide (study 1) or placebo (study 2) was given orally before glucose infusion. Finally, the effect of 160 mg gliclazide was reassessed after a two-month treatment with the same sulfonylurea (80 mg t.i.d.). Basal plasma glucose, insulin, C-peptide and endogenous glucose production (EGP) were similar before the two initial studies. During glucose infusion, EGP was more suppressed after gliclazide in spite of comparable increase in plasma insulin and C-peptide. After the two-month therapy, basal plasma glucose levels and HbA1c were lower while plasma insulin and C-peptide were higher with respect to baseline (p < 0.05). Gliclazide further reduced plasma glucose, the incremental area above baseline, and EGP during glucose infusion, while plasma insulin and C-peptide achieved higher plateaus (p < 0.05). When data were pooled, plasma glucose concentration and EGP correlated both in the basal state (r = 0.71) and during the last hour of glucose infusion (r = 0.84; both p < 0.05). These data suggest that gliclazide enhances the suppression of EGP induced by insulin and that this effect is greater with chronic treatment because of concomitant improvement of insulin secretion.