Spectral cross-cumulants for multicolor super-resolved SOFI imaging

Super-resolution optical fluctuation imaging provides a resolution beyond the diffraction limit by analysing stochastic fluorescence fluctuations with higher-order statistics. Using nth order spatio-temporal cross-cumulants the spatial resolution and the sampling can be increased up to n-fold in all spatial dimensions. In this study, we extend the cumulant analysis into the spectral domain and propose a multicolor super-resolution scheme. The simultaneous acquisition of two spectral channels followed by spectral cross-cumulant analysis and unmixing increases the spectral sampling. The number of discriminable fluorophore species is thus not limited to the number of physical detection channels. Using two color channels, we demonstrate spectral unmixing of three fluorophore species in simulations and experiments in fixed and live cells. Based on an eigenvalue/vector analysis, we propose a scheme for an optimized spectral filter choice. Overall, our methodology provides a route for easy-to-implement multicolor sub-diffraction imaging using standard microscopes while conserving the spatial super-resolution property.

X-ray resonant photoexcitation: linewidths and energies of Kα transitions in highly charged Fe ions

Photoabsorption by and fluorescence of the Kα transitions in highly charged iron ions are essential mechanisms for x-ray radiation transfer in astrophysical environments. We study photoabsorption due to the main Kα transitions in highly charged iron ions from heliumlike to fluorinelike (Fe24+ to Fe17+) using monochromatic x rays around 6.6 keV at the PETRA III synchrotron photon source. Natural linewidths were determined with hitherto unattained accuracy. The observed transitions are of particular interest for the understanding of photoexcited plasmas found in x-ray binary stars and active galactic nuclei.

STED nanoscopy reveals molecular details of cholesterol- and cytoskeleton-modulated lipid interactions in living cells

Details about molecular membrane dynamics in living cells, such as lipid-protein interactions, are often hidden from the observer because of the limited spatial resolution of conventional far-field optical microscopy. The superior spatial resolution of stimulated emission depletion (STED) nanoscopy can provide new insights into this process. The application of fluorescence correlation spectroscopy (FCS) in focal spots continuously tuned down to 30 nm in diameter distinguishes between free and anomalous molecular diffusion due to, for example, transient binding of lipids to other membrane constituents, such as lipids and proteins. We compared STED-FCS data recorded on various fluorescent lipid analogs in the plasma membrane of living mammalian cells. Our results demonstrate details about the observed transient formation of molecular complexes. The diffusion characteristics of phosphoglycerolipids without hydroxyl-containing headgroups revealed weak interactions. The strongest interactions were observed with sphingolipid analogs, which showed cholesterol-assisted and cytoskeleton-dependent binding. The hydroxyl-containing headgroup of gangliosides, galactosylceramide, and phosphoinositol assisted binding, but in a much less cholesterol- and cytoskeleton-dependent manner. The observed anomalous diffusion indicates lipid-specific transient hydrogen bonding to other membrane molecules, such as proteins, and points to a distinct connectivity of the various lipids to other membrane constituents. This strong interaction is different from that responsible for forming cholesterol-dependent, liquid-ordered domains in model membranes.

Laser Doppler imaging for intraoperative human brain mapping

The identification and accurate location of centers of brain activity are vital both in neuro-surgery and brain research. This study aimed to provide a non-invasive, non-contact, accurate, rapid and user-friendly means of producing functional images intraoperatively. To this end a full field Laser Doppler imager was developed and integrated within the surgical microscope and perfusion images of the cortical surface were acquired during awake surgery whilst the patient performed a predetermined task. The regions of brain activity showed a clear signal (10-20% with respect to the baseline) related to the stimulation protocol which lead to intraoperative functional brain maps of strong statistical significance and which correlate well with the preoperative fMRI and intraoperative cortical electro-stimulation. These initial results achieved with a prototype device and wavelet based regressor analysis (the hemodynamic response function being derived from MRI applications) demonstrate the feasibility of LDI as an appropriate technique for intraoperative functional brain imaging.

Six-month efficacy of benfluorex vs. placebo or metformin in diet-failed type 2 diabetic patients

Six-month efficacy of benfluorex (Mediator) (150-450 mg/day) was assessed in a double-blind multicenter study vs. placebo or metformin hydrochloride (850-2550 mg/day). After a 2-month run-in period of strict dieting, 722 type 2 diabetic patients were randomized (1:2:2) to receive placebo (n=144), benfluorex (n=294) or metformin (n=284). After a 5-week dose-finding phase, the efficacy of benfluorex was compared with that of placebo (test for difference, main analysis) and metformin (non-inferiority test, secondary analysis) during a 6-month fixed-dose treatment. At entry after strict dieting, there was no difference between groups for HbA(1C) (placebo, 7.4%+/-1.5%; benfluorex, 7.7%+/-1.6%; metformin, 7.8%+/-1.6%) and fasting plasma glucose (FPG; placebo, 9.7+/-2.3 mmol/l; benfluorex, 10.0+/-2.0 mmol/l; metformin, 10.2+/-2.5 mmol/l). At the end of the dose-finding phase, mean doses were 2.71 tablets/day for placebo group, 2.65 tablets/day for benfluorex (397.5 mg/day) and 2.50 tablets/day for metformin (2125 mg/day). At the end of treatment, HbA(1C) level decreased by 0.60% ( p<0.001) in benfluorex patients while it increased by 0.50% ( p<0.001) with placebo (intent-to-treat analysis). The mean endpoint difference was -0.86% (SE, 0.17%; p<0.001). Mean endpoint difference in HbA(1C) between benfluorex and metformin was 0.28% (SE, 0.12%) [90% CI, 0.07 to 0.48] (non-inferiority test, p=0.037). Treatment with benfluorex was well tolerated; 39% of these patients reported one or more emergent adverse events (compared to 38% on placebo and 43% on metformin) and only two patients suffered a treatment-related, serious adverse event. This study demonstrates that benfluorex: (1) significantly reduces HbA1C and fasting plasma glucose when compared to placebo; (2) has a good safety profile; and (3) has relatively lower potency compared to metformin, although the non-inferiority test (equivalence limit for HbA(1C) of 0.5%) was significant.

[Severe decubitus ulcer: risk factors and nursing requirements in the terminal life phase]

We present an analysis of the risk factors, the origin and the nursing and medical practice of 140 deaths with high-grade pressure sores which had been detected by post-mortem examination before cremation.

METHODS

All available nursing and medical records from nursing homes and hospitals were screened; in addition, relatives and head nurses were interviewed. The data sources were screened for individual risk factors, information about pressure sore prevention and treatment activities by nursing staff and general practitioners. Moreover, the utilization of pressure relieving devices for patients before and after development of the final decubitus was analyzed.

RESULTS

More than 50% of the pressure ulcers had been incident in nursing homes. The mean duration of the disease was 307 days (median duration 123 days); the maximum duration ranged up to about 6 years. As far as it could be judged from the nursing records, there was a shortfall of nursing quality in terms of prevention efforts which appeared to be frequently inadequate in relation to the risk profile of the residents. Standardized pressure sore record files were missing in most of the cases. General practitioners were not involved in the treatment in 20% of all cases; some of them prescribed an obsolete wound management. In this study 52% of the patients had been classified into the maximum grade within the three-stage German nursing care insurance scheme. In cases of private care information about utilization of financial support and of professional help should be enforced.

DISCUSSION

Being an indicator of nursing quality, shortfalls of prevention measures should be combatted by a broad pattern of quality management strategies which could be adapted from the clinical sector.

Gastric emptying is accelerated in obese type 2 diabetic patients without autonomic neuropathy

OBJECTIVE

To clarify the impact of type 2 diabetes mellitus on the gastric emptying rate.

MATERIAL AND METHODS

Using a double-isotope scintigraphic technique, we assessed the gastric emptying of a standard liquid-solid meal in 13 obese type 2 diabetic patients without autonomic neuropathy (age: 47.4 +/- 8.6 yr, body mass index: 33.9 +/- 4.8 kg/m(2), glycaemia: 9.1 +/- 2.6 mmol/l) and in 7 controls with similar sex ratio, age, BMI and body fat distribution.

RESULTS

The half gastric emptying time for the liquid phase was not significantly different between diabetic patients and controls (respectively: 52.7 +/- 14.5 min and 63.1 +/- 15.2 min). However, the half gastric emptying time for the solid phase was significantly shortened in diabetic patients versus controls (respectively 88.8 +/- 23.2 min in diabetic patients and 113.6 +/- 26.9 min in controls; p<0.04). Furthermore, a negative relationship was highlighted between the half gastric emptying time for the solid phase and basal glycaemia (r=-0.65, p<0.02) in diabetic patients. No significant relationship was found between gastric emptying parameters and cardiac autonomic nerve function, insulin or gastrin levels.

CONCLUSION

Solid gastric emptying is accelerated in obese type 2 diabetic patients without patent autonomic neuropathy when compared to obese non diabetic patients.

Predictive value of cardiac autonomic neuropathy in diabetic patients with or without silent myocardial ischemia

OBJECTIVE

The aim of this study was to determine the predictive value of silent myocardial ischemia (SMI) and cardiac autonomic neuropathy (CAN) in asymptomatic diabetic patients.

RESEARCH DESIGN AND METHODS

We recruited 120 diabetic patients with no history of myocardial infarction or angina, a normal 12-lead electrocardiogram (ECG), and two or more additional risk factors. SMI assessment was carried out by means of an ECG stress test, a thallium-201 myocardial scintigraphy with dipyridamole, and 48-h ECG monitoring. CAN was searched for by standardized tests evaluating heart rate variations. Accurate follow-up information for 3-7 years (mean 4.5) was obtained in 107 patients.

RESULTS

There was evidence of SMI in 33 patients (30.7%). CAN was detected in 33 of the 75 patients (38.9%) who were tested, and a major cardiac event occurred in 11 of them. Among these 75 patients, the proportion of major cardiac events in the SMI+ patients was not significantly higher than that in the SMI- patients (6 of 25 vs. 5 of 50 patients), whereas it was significantly higher in the CAN+ patients than in the CAN- patients (8 of 33 vs. 3 of 42 patients; P = 0.04), with a relative risk of 4.16 (95% CI 1.01-17.19) and was the highest in the patients with both SMI and CAN (5 of 10 patients). After adjusting for SMI, there was a significant association between CAN and major cardiac events (P = 0.04).

CONCLUSIONS

In asymptomatic diabetic patients, CAN appears to be a better predictor of major cardiac events than SMI. The risk linked to CAN appears to be independent of SMI and is the highest when CAN is associated with SMI.

Plasma levels of tumor necrosis factor-alpha (TNF-alpha) are essentially dependent on visceral fat amount in type 2 diabetic patients

TNF-alpha is considered as one of the potential determinants of insulin resistance. However several data suggest that TNF-alpha expression itself, could be modulated by the degree of adiposity and/or plasma insulin levels. To clarify the determinants of plasma TNF-alpha levels in type 2 diabetes mellitus, we studied the impact of intensive insulin treatment on plasma TNF-alpha levels in 16 type 2 diabetic subjects with failure to oral antidiabetic medication (HbA1c: 10.8 +/- 1.2 %). Furthermore, we analyzed the relationship between plasma TNF-alpha levels and total or regional body fat measurements using anthropometry, bienergetic absorptiometry and computed tomography in a cohort of 33 caucasian obese type 2 diabetic subjects (BMI: 32.2 +/- 4.4 kg/m(2) ). The plasma TNF-alpha level was neither affected by plasma glucose level variations nor intensive insulin treatment despite a 37 % decrease in daily insulin needs at the end of insulin therapy (total duration: 11.5 +/- 2.0 days). The plasma TNF-alpha level was similar in men and women and unrelated to age, fasting glycemia or HbA1c. A relationship was highlighted with BMI (r =0.39, p <0.02), but not with total fat mass. This relationship was only dependent on the intra-abdominal fat mass amount as assessed by the waist-to-hip circumference ratio (r =0.52, p <0.01) and the visceral adipose tissue area (r =0.56, p <0. 01). These results show that plasma TNF-alpha levels are essentially dependent on visceral fat amount, thus suggesting that TNF-alpha could be one of the factors mediating insulin resistance and cardiovascular risk in obese type 2 diabetic patients.

Measurement of visceral adipose tissue by DXA combined with anthropometry in obese humans

OBJECTIVE

To get accurate measurements of visceral adipose tissue (VAT) using dual energy X-ray absorptiometry (DXA).

DESIGN

DXA and anthropometric data and their combinations were compared to the VAT area calculated from a computed tomography (CT) single scan.

SUBJECTS

71 overweight subjects (44 women, 27 men), age: 16-70 y, BMI: 27-52 kg/m2.

MEASUREMENTS

Total body and segmental tissue composition, and new parameters obtained from DXA, in addition to waist and hip circumferences and abdominal sagittal diameter measurements.

RESULTS

The ratio measured at the umbilical level (sagittal diameter - subcutaneous fat width) x (transverse internal diameter)/(height) was closely related to VAT (r=0.94 for women and 0.88 for men). It gave the most predictive equation for VAT: y = 79.6x (s.e. 3.9) - 149 cm2 for the whole population (r2=0.86, P<0.0001, root mean square error=38.2 cm2. An independent relationship between lean mass or its index (r=0.52 and 0.72, P<0.001) and VAT was also found in women.

CONCLUSION

This study demonstrates the potential usefulness of DXA to supply accurate measurements of VAT in addition to total body composition determination in obese subjects.

GH deficiency in adults: an epidemiological approach

OBJECTIVE

The prevalence of adult onset GH deficiency (GH-D) is poorly documented. Epidemiological data are now required to estimate the financial cost of GH treatment in adults. The aim of the present study was to estimate the prevalence of GH-D, from a cohort of 1652 adult patients with hypothalamo-pituitary diseases.

DESIGN

The hormonal status of all patients presenting with pituitary diseaseand observed during the year 1994 in 15 endocrine units was retrospectively analyzed, irrespective of the date of disease onset, of the nature and date of pituitary investigations, and whether or not they included specific testing of the GH axis. Of the whole population of 1652 patients, a selected group (RG2) was chosen after exclusion of patients with active acromegaly (n=1414).

RESULTS

GH stimulation tests had been performed in 549 patients of the RG2 group and a documented GH-D was found in 301. A relationship between the value of the GH peak and the number of pituitary deficits was evaluated. For instance, it was shown that 93% of patients with three deficits had GH-D. These results constituted the basis for estimating the number of GH-D in the group of untested patients. The number of GH-D deduced from the number of established GH-D (n=301) and from the number of GH-D hypothesized from other pituitary deficits (n=406) was 707 cases. Prevalence and annual incidence were calculated from data recorded in a referral center with a well-defined catchment area, Marseilles (Bouches du Rhône department). We projected a prevalence of 2638 for France and an annual incidence of 12 GH-D per million of the adult population.

Determinants of echocardiographically measured left ventricular mass in diabetic patients with or without silent myocardial ischaemia

Left ventricular hypertrophy (LVH) is a recognized independent risk factor for cardiovascular morbidity and mortality. The purpose of this study was to assess the determinants of left ventricular mass index (LVMI), according to the presence or absence of silent myocardial ischaemia (SMI), in diabetic patients with at least two additional risk factors but with no known coronary artery disease. Eighty diabetic patients (14 Type 1 and 66 Type 2) were studied, and LVMI was measured echocardiographically. Three non-invasive tests (the ECG stress test, thallium-201 myocardial scintigraphy with intravenous dipyridamole infusion, and ambulatory 48-h ECG monitoring) were performed on all patients. Forty-five percent of patients had LVH (LVMI > or = 110 g/m2 in men and > or = 106 g/m2 in women). Twenty-six patients (37%) had SMI assessed on at least one of the non-invasive tests, 7 of whom had significant coronary stenoses on angiography. LVMI was significantly higher in patients with coronary stenoses on angiography than in those with SMI but without coronary stenoses or in those without SMI (p < 0.05), and was correlated with systolic blood pressure. In patients free of SMI, LVMI correlated with creatininemia. In patients with SMI and normal coronary arteries on angiography, LVMI correlated with the waist/hip girth ratio, the log urinary albumin excretion rate and the red blood cell filtration index (a rigidity index). This study suggests that LVH is very frequent in diabetic patients and that the main factor contributing to the increase of LVMI differs according to the presence or absence of SMI and coronary stenoses: volume load in patients free of SMI, microcirculatory disorders in those with SMI but with normal coronary arteries, and blood pressure in those with coronary stenoses.

[Management of DNA banks: ethical concerns]

With the creation of DNA banks, short and long-term studies can be conducted on the DNA of many individuals using stored cells and tissues. These studies allow an analysis of the pathophysiological impact of genetics and help define individual markers predictive of risk. Genome analysis is thus an important advance in medical science, providing essential information for establishing appropriate measures to slow disease development, limit severity or improve safe recovery. The use of genetic results may however have an adverse effect in certain situations if the genetic information collected were deviated from its purely medical purpose under the influence of social, occupational or economic factors. The aim of our study was to analyse the ethical challenges linked to the implementation of DNA banks in France, particularly to see how to maintain the concept of individual protection in biomedical research within the patient-physician relationship in the current context of legal and administrative regulations in France. In this study, we discuss a set of criteria which should be systematically evaluated in information collection and consent procedures prior to blood or tissue procurement for DNA bank purposes.

Insulin and body fat distribution have no direct effect on plasma leptin levels in obese Caucasian women with and without type 2 diabetes mellitus

Leptin, a hormone produced by adipose tissue, is potentially involved in the regulation of adiposity. The effects of insulin and body fat distribution on human plasma leptin have not yet been clearly defined. The present study investigated the relationships between plasma leptin and total and regional body fat parameters measured by anthropometry and bienergetic absorptiometry associated or not with computed tomography, taking glucose metabolism into account. A cohort of 51 obese Caucasian women (23 with normal glucose tolerance, 11 with impaired glucose tolerance, and 17 with Type 2 diabetes) was analysed. All non-diabetic subjects had an oral glucose tolerance test together with plasma glucose and insulin measurements. Moreover, a subgroup of 7 diabetic subjects with failure to oral antidiabetic treatment was submitted to about 12 days of intensive subcutaneous insulin therapy. Plasma leptin was essentially dependent on total body fat mass (r = 0.83, p < 0.0001, for the whole population), but not related to adipose tissue distribution. An independent correlation between leptin adjusted on body fat mass and fasting insulinaemia (R = 0.72, p < 0.02) or C-peptide (R = 0.62, p < 0.03) was found significant only in the diabetic group. Insulin treatment was associated with a moderate and transient increase of plasma leptin. The relative variations of plasma leptin levels were strongly negatively correlated with those of free fatty acids. The present data confirm that plasma leptin is not dependent on body fat distribution and suggest an indirect effect of insulin on leptin secretion in clinical conditions.

Influence of endogenous and environmental factors on variations of serum lipoprotein (a) concentrations in a large population of insulin-treated diabetic patients

Variations of serum Lp(a) concentrations were studied in a large population of insulin-treated diabetic patients in relation to the type of diabetes, insulin treatment and long-term complications. Lp(a) concentrations were measured by immunonephelometry in 740 diabetic patients [493 insulin-dependent diabetic (IDDM) patients and 247 insulin-treated Type 2 diabetic (ITD) patients]. Concentrations and distributions were compared with those of 128 non-diabetic controls. Correlations were investigated with lipidic and glycaemic parameters, daily lipid intake, body mass index (BMI), macrovascular and nephropathic complications, and insulin therapy. Both groups of insulin-treated patients (IDDM and ITD) displayed significantly higher Lp(a) concentrations when compared to controls. No relationship was found with macrovascular complications and nephropathy, except in IDDM patients in whom Lp(a) was elevated when creatinine concentration was above 120 mumol/L. Mean variations of Lp(a) were correlated with BMI and triglyceride variations in IDDM patients and only with triglycerides in ITD patients. These results suggest a direct and/or indirect (via serum triglycerides) potential role of exogenous insulin in the modulation of serum Lp(a) concentrations. BMI and lipid daily fat intake could be considered as additional modulating factors of Lp(a) serum concentrations in ITD patients.

Added benfluorex in obese insulin-requiring type 2 diabetes

To determine the effect of benfluorex on glycaemic control in obese insulin-requiring Type 2 diabetes, 76 patients (aged 53.8 +/- 12.8 years) receiving insulin (> or = 0.5 IU/kg) and an appropriate low-calorie diet were evaluated after a 1-month run-in followed by a 3-month double-blind treatment period (3 tablets daily) with benfluorex (B; n = 37) vs placebo (P; n = 39). At inclusion, the B and P groups respectively did not differ in body weight (80.9 +/- 10.3 vs 77.2 +/- 9.1 kg), body mass index (BMI) (30.1 +/- 4.6 vs 29.0 +/- 2.3 kg/m2) or fasting blood glucose (11.22 +/- 4.33 vs 10.35 +/- 4.42 mmol/l). However, daily insulin dose and HbA1c levels were higher in the B group (59.9 +/- 18.6 vs 50.4 +/- 12.8 IU, p = 0.012; and 7.72 +/- 1.60 vs 6.96 +/- 1.27%, p = 0.025, respectively). After 3 months of treatment, the decrease in daily insulin dose was greater in the B group (8.7 +/- 10.1 vs 2.7 +/- 8.1 IU; p = 0.032), with a decrease in HbA1c (-0.73 +/- 1.74%, p = 0.026), vs no change in the P group (+0.01 +/- 1.65%, NS) and a tendency towards a greater decrease in fasting blood glucose (-1.43 +/- 5.41 vs +0.42 +/- 3.78 mmol/l respectively). Body weight and BMI were also lower in the B group (1.77 ñ 2.27 vs 0.21 ñ 2.68 kg, p = 0.013; and 0.64 +/- 0.84 vs 0.07 +/- 1.07 kg/m2, p = 0.019, respectively) in parallel with the decrease in insulin dose. Triglycerides decreased in the B group vs an increase in the P group (-0.54 +/- 2.04 vs +0.21 +/- 0.70 mmol/l p = 0.06). Total cholesterol decreased within the B group (-0.47 +/- 1.01 mmol/l; p = 0.013) and vs the P group (intergroup p = 0.006). Adverse events were reported in 11 patients in the B group vs 5 in the P group (NS), causing dropout in only one case (intercurrent illness, P group). Addition of benfluorex in obese insulin-requiring Type 2 diabetes thus enhances glycaemic control and lowers both daily insulin requirement and body weight. Benfluorex + insulin is a valid alternative for obese patients who remain poorly controlled despite insulin or who require high doses of insulin.

Silent myocardial ischaemia and left ventricle hypertrophy in diabetic patients

The purpose of this study was to evaluate the ability of three noninvasive techniques to detect silent myocardial ischaemia and analyse the factors associated with this condition, particularly left ventricular hypertrophy, in diabetic patients. An ECG stress test, a thallium-201 myocardial scintigraphy with dipyridamole intravenous infusion, ambulatory 48 h ECG monitoring and an echocardiographic study were performed in 92 diabetic patients without cardiac symptoms but with > or = 2 additional cardiovascular risk factors. At least one of these tests was positive in 28 patients (30.4%), suggesting silent myocardial ischaemia. Twenty-four of these patients had a coronary angiography which showed significant coronary stenosis in only 9 cases. An accurate echocardiographic tracing was obtained in 79 patients, particularly in 7 of the 9 with coronary stenosis. Left ventricular hypertrophy was detected in 34 patients, 6 of whom had coronary stenosis. In patients with left ventricular hypertrophy, the positive predictive values of myocardial scintigraphy and the ECG stress test were respectively 50% and 100%, as compared to only 33% and 11% in those without hypertrophy. In summary, coronary stenoses were found in < 10% of asymptomatic diabetic patients with > or = 2 cardiovascular risk factors, but more frequently in individuals with left ventricular hypertrophy. Thus, silent myocardial ischaemia should be searched for first in diabetic patients with hypertrophy, for which the stress test was the most accurate detection method in this study.

Short-term intensive insulin therapy in insulin-requiring diabetes: effectiveness and factors predicting success

Insulin-requiring diabetes (IRD) is a condition of permanent blood glucose imbalance which occurs despite a regulated diet and treatment with maximum doses of oral anti-diabetic drugs (glibenclamide 15 mg/d + metformin 1,700 mg/d). This report describes the results of a 2-year prospective study in 75 IRD patients treated to eliminate their insulin requirement. All had residual endogenous insulin secretion (REIS) (urinary C peptide > 80 micrograms/24 h and/or basal C peptide > 2.4 ng/ml) and were treated for 10 days by subcutaneous insulin infusion via a portable pump. REIS was measured, and insulin resistance was determined by an insulin tolerance test (ITT) to define their insulin sensitivity index (DG/G) before and after 10-day intensive therapy. The patients were monitored as outpatients, and the attempt at remission was considered to be a failure (F) or a success (S). Thirty of the 75 patients (40%) were in remission at 1 year, and 14/67 (21%) at 2 years. No clinical criterion differentiated successes from failures at 1 year, nor was the initial degree of blood glucose imbalance or the REIS predictive of the metabolic changes that occurred after insulin therapy. However, the drop in the insulin requirement (IR) (-26% for F and -39% for S, p < 0.05) and the increases in the DG/G index (+68 +/- 51% for F and 176 +/- 50% for S, p < 0.01) after insulin therapy were indicative of their condition 1 year later. Receiving operating characteristic curves showed that a 35% decrease in IR and an 80% increase in DG/G were indicative of a successful outcome at 1 year, with a specificity and sensitivity of about 70%. It is concluded that a decrease in daily IR and an increase in the DG/G index during insulin treatment are prognostic indicators of the course of insulin-requiring diabetics after temporary intensive insulin treatment.

Post-prandial metabolism of triglyceride-rich lipoproteins in non-insulin-dependent diabetic patients before and after bezafibrate treatment

Retarded post-prandial (pp) lipid clearance is potentially a major component of the increased cardiovascular risk incurred by hypertriglyceridaemic non-insulin-dependent diabetic mellitus (NIDDM) patients. The effect of bezafibrate (Bz, 400 mg per day for 5 weeks on chylomicron (CM) and remnant clearance after loads of 100 g of fat and vitamin A was therefore explored in 10 male patients (glycaemia 11.9 +/- 3.3 TG 4.5 +/- 2.4 mmol L(-1)). In all subjects CM-TG and retinyl palmitate (RP) were reduced by 50%, but 8-h non-CM (remnant) RP decreased only in initially mildly hypertriglyceridaemic subjects (-35%, P < 0.05), while in three patients with very elevated initial TG (epsilon3/3, epsilon3/2 and epsilon2/2 genotypes) 8-h remnant RP increased by 100%. The decrease in pp CM-TG correlated with that of fasting Sf 20-400 (r = 0.686, P = 0.026), suggesting that improved lipolysis was a major determinant of hypolipidaemic effect. Apo CIII synthesis is known to be depressed by Bz: concentrations were lower under Bz (P < 0.05). A positive correlation (r = 0.880, P < 0.001) with fasting TG before treatment and its disappearance after treatment suggested an involvement of high concentrations with hypertriglyceridaemia. Post-prandial non-esterified fatty acids were decreased by 35 in correlation with a significant (-19%, P < 0.05) improvement in fasting glycaemia (r = 0.801, P < 0.005). These results suggest that Bz acts both on lipolysis and on removal of CM remnants, but that removal can become saturated when lipolysis is massively improved.

Serum lipoprotein (a) concentrations in a population of 819 non-insulin-dependent diabetic patients

Variations in serum Lp(a) concentrations were studied in a large population of non-insulin-dependent diabetic (NIDDM) patients in relation to long-term complications. Lp(a) concentrations were measured by immunonephelometry in 819 NIDDM subjects and compared with those of 128 controls. Correlations were investigated relative to plasma lipid and glycaemic parameters, body mass index (BMI) and macro- and microvascular complications. Mean absolute and relative variations of Lp(a) concentrations were studied in a subgroup of 245 patients over a one-year period. No significant differences were found between Lp(a) concentrations in NIDDM and control subjects. No relationship was evidenced with macrovascular and microvascular complications or glycaemic control. Mean relative Lp(a) variations were correlated with BMI and absolute and relative variations in triglyceridaemia. These results confirm the absence of any alterations of Lp(a) concentrations in a large cohort of NIDDM patients, either with or without micro- and macrovascular complications, but suggest a particular modulatory role for BMI and serum triglyceride variations.

Postprandial cholesteryl ester transfer and high density lipoprotein composition in normotriglyceridemic non-insulin-dependent diabetic patients

Altered postprandial HDL metabolism is a possible cause of defective reverse cholesterol transport and increased cardiovascular risk in diabetic patients with a normal fasting lipoprotein profile. Ten normolipidemic, normoponderal non-insulin dependent diabetes mellitus (NIDDM) patients and seven controls received a 980 kcal meal containing 78 g lipids with 100 000 IU vitamin A. Chylomicron clearance was not different, but area under the curve (AUC) for retinyl palmitate in chylimicron-free serum (remnant clearance) was greater in patients (P < 0.02). LCAT activity increased postprandially to the same extent in both groups. In control subjects, cholesteryl ester transfer protein (CETP) activity (CETA) also increased by 20% (P < 0.01 at 6 h) in parallel with a 20% decrease in HDL2-CE (r = -0.55, P = 0.009). In NIDDM patients, on the contrary, CETA which was 35% higher in the fasting state (P < 0.005), decreased postprandially yet HDL2-CE remained unchanged. Postprandial HDL3 of controls were enriched with phospholipid (PL) (30.3 +/- 2.6% at 6 h) with respect to fasting (25.6 +/- 2.5%, P < 0.01) and to NIDDM-HDL3 (25.8 +/- 1.7% at 6 h, P < 0.01). These results show that variation in plasma CETA has little impact on HDL2-CE in NIDDH subjects. They support the concept that, in controls, the combined enrichment of HDL3 with PL, increased LCAT and CETA create the conditions for stimulation of cell cholesterol efflux and CE transfer to apo B lipoproteins. In NIDDM, because of the lesser HDL3 enrichment with PL and of the inverse trend of CETA, these conditions fail to occur, depriving the patients of a potentially efficient mechanism of unesterified cholesterol (UC) clearance, despite their strictly normal preprandial profile.

[Respiratory burst of neutrophils and cytokine profile in the non-insulin-dependent diabetic]

Many clinical and experimental data are in favour of a participation of leukocytes in vascular disease. Diabetes, a risk factor, is associated with a dysfunction of neutrophils. If chemotaxis and phagocytosis are deficient, it is not clearly established whether superoxide generation is conserved in these patients. We have measured this function in 35 noninsulin dependent diabetic patients, compared with a control population. We have assessed, in parallel, a profile of the cytokines involved in vascular phenomenons including TNF alpha, IL-1 beta et IL-6. Our results indicate that the generation of free radicals is normal in diabetics, with a significant elevation of TNF alpha. These results suggest a possible participation of this cytokine in the modulation of granulocyte reactivity.

[Diabetes mellitus and atherosclerosis. Physiopathology of diabetic macroangiopathy]

Numerous prospective epidemiological studies point out high mortality prevalence in diabetic subjects. Classical risk factors, especially arterial hypertension and hypertriglyceridaemia, are abnormally associated with diabetes mellitus. However, they don't account for overall surmortality in this disease. Additional markers of cardiovascular risk appeared as albuminuria, abdominal obesity, and the couple insulinoresistance/hyperinsulinism. Physiopathological intrinsic mechanisms inherent to macroangiopathy are multiple and intricate (hemostatic disorders, endothelial impairments, oxidative stress, quantitative and qualitative lipoproteins abnormalities, part of hyperinsulinism and growth factors). Strict normoglycaemia and exacting control of all other risk factors is essential. Use of other therapeutic agents as antioxidants and antiagregants, is discussed.

[Insulin tolerance tests]

Impaired sensitivity to insulin is a frequent clinical situation and interest in measuring sensitivity to insulin has greatly increased since Reaven described the X syndrome in 1988. This syndrome is an association of increased serum triglycerides, high blood pressure, low levels of HDL and insulin resistance; affected patients have an increased risk of coronary artery disease. Several methods have been described to measure insulin resistance. They rely on the effect of insulin on glucose metabolism. The euglycaemic clamp interprets the interactive feedback control between insulin and glucose. Insulin is infused to reach a constant serum insulin level, then glucose is administered at predetermined levels. The blood glucose level thus corresponds to hepatic production and insulin sensitivity is expressed as the amount of glucose infused in mg/kglmin. Metabolic glucose clearance is the relationship between glucose consumption and blood glucose level during the test. This method is reliable, reproducible and eliminates the errors related to insulinindependent metabolism. Steady state plasma glucose relies on drugs which suppress endogenous insulin secretion. Glucose and insulin are then infused at constant rates and the resulting glucose and insulin levels express insulin sensitivity. This method is technically difficult to handle and is used less often. Bergman's minimal model and the modified insulin tolerance test offer other more practical and global methods with particular indications. Each method has its advantages and disadvantages in terms of precision, cost and duration. The choice of a method is basically made as a function of the clinical or research needs.

Roles of LH and insulin resistance in lean and obese polycystic ovary syndrome

OBJECTIVE

The relationship between insulin resistance and hyperandrogenism led us to study insulin resistance in polycystic ovary syndrome (PCOS) in order to determine its prevalence and pathogenesis.

DESIGN

Blood samples were taken on the 8th day after menses commenced.

PATIENTS

Sixty-one women with PCOS, 30 with normal weight (BMI < 25 kg/m2) (group 1) and 31 with obesity (BMI > 26 kg/m2) (group 2) were studied. They were divided also according to LH level: group A, low or normal LH (n = 23) and group B, high LH (n = 38). Twenty lean control women and 16 obese control women were studied.

MEASUREMENTS

Serum LH, testosterone, free testosterone, dehydroepiandrosterone, sex-hormone binding globulin, androstenedione, and fasting insulin were measured. Insulin sensitivity was explored by the insulin tolerance test (ITT). ITT was performed by bolus i.v. insulin of 0.1 IU/kg. Blood glucose was measured before (-5,0) and after injection (3, 5, 7, 10, 15 minutes). Insulin sensitivity was given by the ratio of glycaemic variation to initial blood glucose (delta G/G index).

RESULTS

delta G/G was correlated with other insulin resistance parameters, particularly fasting insulin r = 0.40, P < 0.01. The PCOS groups had the following insulin resistances (mean +/- SEM) compared to matched groups: delta G/G lean PCOS vs lead controls: 0.45 +/- 0.02 vs 0.61 +/- 0.01, P < 0.001; delta G/G obese PCOS vs obese controls: 0.32 +/- 0.02 vs 0.40 +/- 0.01, P < 0.02. Insulin resistance was higher in group A than in group B: delta G/G 0.29 +/- 0.02 vs 0.45 +/- 0.02, P < 0.001. The prevalence of insulin resistance was 63% in lean PCOS and 51% in obese PCOS. Positive correlations between delta G/G index and LH were found in group 1 and 2, respectively r = 0.45, P < 0.01 and r = 0.55, P < 0.01.

CONCLUSION

PCOS was associated with a significant decrease of insulin sensitivity, independent of obesity. The correlation between LH and insulin sensitivity suggests a complementary action in PCOS.

Study of the rate of early glucose disappearance following insulin injection: insulin sensitivity index

The euglycaemic hyperinsulinaemic glucose clamp is usually considered as the reference technique to evaluate insulin sensitivity. As it is an expensive and time-consuming tool, we therefore tried to validate a simple insulin tolerance test (ITT) (IV bolus of 0.1 IU/kg of regular insulin, with glucose sampling at -5, 0, 3, 5, 7, 10 and 15 min) and to demonstrate its usefulness. Insulin sensitivity was measured by DG/G0 ratio (G0 = initial glycaemia, DG is the variation between G0 and the glycaemia obtained at 15 min by the calculation of the regression plot). We confirmed the existence of a correlation between the glucose uptake (mg/kg per min) evaluated by glucose clamp and the DG/G0 index (r = 0.9, P < 0.01). There was no stimulation of hormonal counter regulation during the test. The ITT was significantly correlated both with fasting insulin (r = -0.43, P < 0.01), and post-glucose load insulin concentration (r = -0.67, P < 0.01); each measurement expressing insulin sensitivity. Four groups of patients with different insulin sensitivity: controls, NIDDM, gynoid and android obese subjects, were clearly separated by ITT. We showed that fasting glycaemia and DG/G0 were correlated (y = 2.63/x - 0.093; r = 0.82, P < 0.01). These results suggest that ITT could be an easy, quick and low cost method to evaluate insulin resistance in clinical practice and epidemiological studies.

Heterogeneity in the mutations responsible for X chromosome-linked Kallmann syndrome

Kallmann syndrome represents the association of hypogonadotropic hypogonadism with anosmia. Three modes of transmission, X chromosome-linked, autosomal recessive and autosomal dominant, have been described. The KAL gene, responsible for the X-linked form of the disease, has been isolated and its intron-exon organization recently determined. We have searched for mutations of the KAL gene in 21 unrelated males affected by familial Kallmann syndrome. In these families, segregation of the disease was suggestive of the X-linked mode of transmission. In 2 families, large Xp22.3 deletions, both including the entire KAL gene, have been detected by Southern blot analysis. Here we report the sequence analysis of the entire coding region of the KAL gene in the 19 remaining patients. The approach consisted of sequencing each of the 14 coding exons and splice site junctions. Each exon was amplified by PCR on the genomic DNA, using oligonucleotides from the flanking intronic sequences as specific primers. Nine point mutations were identified at separate locations in four exons and one splice site, providing strong evidence for heterogeneity in mutations responsible for the X-linked Kallmann syndrome. In addition, the high frequency of unilateral renal aplasia in X-linked Kallmann patients (6 out of 11 males with identified alterations of the KAL gene) should be emphasized.

[Lipoprotein (a) and diabetes: relationship based on 224 cases]

Recent studies have suggested that Lp(a) is implicated in the high incidence of coronary heart disease in diabetic subjects, but data are still controversial. We therefore studied the distribution of plasma Lp(a), assayed by radial immunodiffusion, in a group of 224 diabetics and compared them to 92 non diabetic controls. Besides plasma Lp(a), TG and glucose were evaluated in 16 insulin-requiring diabetic patients before and after 10 days of normoglycaemia. The distribution of plasma Lp(a), as usually skewed to the left, was not different either between diabetic subjects and controls or between Type 1 and Type 2 diabetic subjects. No significant correlation was observed between Lp(a) and glycaemic control expressed by HbA1c. The sequence of normoglycaemia did not affect plasma Lp(a), no significant correlation between the variations of glycaemia and Lp(a) levels and the variations of triglyceridaemia and Lp(a) levels were found. Thus our group of diabetic subjects has a similar distribution of Lp(a) to controls. Lp(a) concentrations do not seem to be affected by chronic hyperglycaemia or rapid normalisation of glycaemic levels. However there is a strong need of standardization of Lp(a) assay before any definitive conclusion. As we have so far no efficient treatment for lowering Lp(a) in daily clinical practice, the energetic care of other associated vascular risk factors is needed.

[Insulin-dependent diabetes and organ specific autoimmune diseases: a retrospective clinical and immunogenetic study of 165 consecutive cases]

We analysed clinical and immunological indexes in 165 caucasian adult patients presenting insulin-dependent diabetes mellitus associated with other organ-specific autoimmune diseases (type Ib IDDM). As diagnostic strategy, we recommend testing thyrogastric autoantibodies at diabetes onset and islet-cells antibodies three years after.

[Relationship between lipoprotein(a) and non-insulin-dependent diabetes in 602 patients]

Lipoprotein (a) status has been evaluated in a population of 602 non insulin-dependent diabetics and compared to 74 healthy controls. There was no significant difference in concentration and no obvious influence of glycaemic, coronarian or renal status.

[Theoretical aspects of the relationship between diabetic macroangiopathy and hyperinsulinism]

Epidemiological and clinical data suggest a relationship between hyperinsulinism and macroangiopathy in non insulin-dependent diabetes. On the other hand, a relationship between the plasma free insulin level and macroangiopathy has not been documented in insulin-dependent diabetes. Other abnormalities in addition to hyperinsulinism and glucose intolerance are frequently associated in the presence of insulin resistance and have been grouped by Reaven under the term syndrome X: raised VLDL triglycerides, decreased HDL, and raised blood pressure. Iatrogenic hyperinsulinism appears to be an arterial risk factor, but by what mechanism may it also constitute an independent risk factor? The following theoretical aspects of a possible atherogenic role of hyperinsulinism are currently being investigated: a) insulin stimulates the proliferation and migration of smooth muscle cells either directly or via a rise in IGF1; b) insulin induces lipogenesis in the intima-media, but it has not been demonstrated that this in situ lipogenesis is atherogenic; c) insulin raises the VLDL production, decreases HDL and modifies the clearance of LDL; d) insulin increases blood pressure by stimulating both the renal reabsorption of sodium and the sympathetic nervous system; insulin resistance may also be expressed at the level of the Na-K-ATPase of vascular smooth muscle cells by decreasing the vasodilator effect of the hormone; e) lastly, insulin induces a defect of fibrinolysis mediated by an increase in the level of plasminogen activator inhibitors (PAI1). In conclusion, the combination of hyperglycemia and hyperinsulinism is probably damaging to the artery. Therapeutic intervention studies are necessary to confirm and define the role of hyperinsulinism in macroangiopathy and to answer the unresolved questions: direct or indirect role? effect of endogenous and/or exogenous hyperinsulinism?

Remission of insulin requirement in late secondary failure to oral hypoglycemic agents (IRD): results at 24 months and analysis of predictive factors

Over the last four years, we have done a prospective study of insulin requiring diabetes (IRD). We offered 59 patients insulin therapy during 10 to 14 days by means of continuous subcutaneous insulin injection with the help of a pump in order to maintain the patient under oral hypoglycemic agents (OHA). We divided our population into two characteristic groups and isolated parameters that were predictive of post-insulin therapy evolution by means of C peptide assays. In one group, in 50% of cases, endogenous insulin production appeared impaired and could not be restored by insulin therapy. The patients in this group suffered a renewed drug failure within 3 months. In the other group, 50% of cases, endogenous insulin production was preserved and the CP/blood glucose level ratio improved. On insulin treatment interruption, we observed a significantly improved fasting blood glucose level and we observed decreased insulin needs. The patients, who were probably insulin resistant, suffered only late failures or went into remission, often for longer than one year. The data bring us to the logical conclusion of IRD heterogeneity. Only some of these patients can benefit from temporary insulin therapy and the remission attempt should be limited to them.

[Insulin-requiring diabetes]

The insulinorequiring diabetes is a notion which deserves a clear definition, essentially clinical, because it covers a wide range of physiopathological situations. The progressive degradation of Diabetes type II means a progressive discrepancy of insulinosecretion and above all an increase of insulinoresistance. The noxious part of chronical hyperglycemia is at present well known. The present therapeutical prospects tend to delay or limit insulinotherapy, by trying to obtain remission of insulinorequiring and some attempt to give a combined treatment associating insulin and hypoglycemic drugs.