Determination of a redox compensation index and its relationships to glycaemic control in type 2 diabetes mellitus.

The measurement of single parameters of oxidative stress in biological fluids can often give results difficult to interpret as to the real involvement of oxidative processes in a given disease condition. In the present study we propose a novel integrated parameter, called "redox compensation index", obtained by combining the results of two established and convenient procedures, i.e. the Fox-2 assay for plasma lipid hydroperoxides and the ferric reducing/antioxidant power (FRAP) assay for total antioxidant potential of plasma. These procedures were employed for the evaluation of oxidative stress in a group of patients with type 2 diabetes mellitus, a condition in which oxidative processes are implicated in the development of complications. In type 2 diabetic patients, plasma lipid hydroperoxides were directly correlated with levels of glycated hemoglobin. On the other hand, a significant inverse correlation was observed between levels of glycated hemoglobin and redox compensation values. The data reported suggest that the redox compensation index could represent a convenient parameter for the direct appraisal of oxidative status in clinical subjects, and are in support of the proposed role of protein glycation in production of oxidative alterations during type 2 diabetes mellitus.

[Effect of naloxone and naltrexone on the postprandial energy expenditure and endocrine pancreas response to a mixed meal in essential obesity]. / Effetto del naloxone e del naltrexone sulla spesa energetica post-prandiale e sulla risposta del pancreas endocrino ad un pasto misto nell'obesità essenziale.

It has been recently shown that the opioid antagonists naloxone and naltrexone are able to reduce appetite and to raise energy expenditure in animal models. The results of studies in humans are inconclusive. In 10 female obese patients we have evaluated the effects of naloxone infusion (2 mg/2 h) on energy expenditure, measured by indirect calorimetry (Deltatrac) and on plasmatic levels of glucose, insulin, glucagon and somatostatin, fasting and after the assumption of a standard 567 kcal meal (C = 20%, P = 20%, L = 60%). We have repeated the tests after a dietary period of 1 month, associated with naltrexone assumption. Acute administration of naloxone caused similar effects at the beginning and at the end of the study; we have observed a raise of caloric expenditure, a decrease of hyperinsulinemia and a high response of somatostatin to metabolic stimulus. After therapy, even with a weight reduction of 6%, we haven't observed either variations of energy expenditure or hormonal level changes. We conclude that in obese women opioid hypertone plays a role in thermic effect of meals and in the impaired response to the nutrients of the gastroenteropancreatic axis. The absence of any effects of naltrexone on the variables that we have studied is perhaps due to the difference in the dose, way of administration and of the different action on the target receptor by the two opioid antagonists.

Prevalence of glomerular hyperfiltration and nephromegaly in normo- and microalbuminuric type 2 diabetic patients.

Glomerular hyperfiltration, correlated with nephromegaly, is a frequent finding in type 1 (insulin-dependent) diabetes. In type 2 (non-insulin-dependent) diabetes, very few studies have been performed, and the results have been inconclusive. Glomerular filtration rate (GFR) and kidney volume, using 99mTc-DTPA scintigraphy and ultrasonography, respectively, were evaluated in 58 control subjects and 163 type 2 diabetic patients; 79 of whom were normoalbuminuric and 84 microalbuminuric. In the two groups of patients, these parameters did not differ significantly from those of controls, even when hypertensive subjects were excluded. Glomerular hyperfiltration was observed in 10 cases; all were normotensive (9.8%), of whom 7 were normoalbuminuric and 3 microalbuminuric. Nephromegaly was observed in 3 other normotensive microalbuminuric diabetic patients. Hypertensive subjects showed a lower GFR than normotensive patients and control subjects. Multivariate analysis showed a negative correlation between glomerular filtrate and systolic blood pressure (BP) in the overall population of patients and in normo- and microalbuminuric patients taken separately. It is concluded that the relationship between these variables forms a continuum in our type 2 diabetic patients; it may also be important in determining the low prevalence of hyperfiltration and nephromegaly found in our patients, who had BP levels higher than those of controls.

[Glomerular filtration and renal volume in type II diabetes (non-insulin-dependent): study in normal and microalbuminuria patients]. / La filtrazione glomerulare ed il volume renale nel diabete tipo II (non-insulino dipendente): studio nei pazienti normo e microalbuminurici.

In type 2 diabetes elevated glomerular filtration rate (GFR) and increased renal volume (RV), often accompanied to normo or microalbuminuria, were demonstrated. This condition is considered a pathogenetic factor for clinical nephropathy. As this topic is little studied in type 2 diabetes, we have investigated 73 type 2 diabetic patients (34 normo and 39 microalbuminuric), looking for a correlation between GFR, RV, hypertension, duration of diabetes and indexes of metabolic control. GFR was measured by a scintigraphy, after infusion of 99Tc-DTPA. Renal volume was determined by ultrasound scanning. Between the groups GFR and RV weren't different; elevated GFR was demonstrated in 3 patients; increased RV in 1 patient. In the hypertensive group GFR was lower than in normotensive group and in controls. Multivariate analysis in stepwise demonstrated that GFR presents a negative correlation to systolic blood pressure as in normo as in microalbuminuric patients. In the normotensive group GFR didn't correlate to the other variables. The present data suggest that in type 2 diabetes there is a little prevalence of glomerular hyperfiltration and increased renal volume and that hypertension plays a role on GFR of hypertensive diabetic patients.

[Validity of the first morning urine collection for screening for microalbuminuria in the diabetic]. / Validità della raccolta urinaria del primo mattino per lo screening della microalbuminuria nel diabete.

With the aim of evaluating the reliability of morning urine collection, compared to the overnight period, in the assessment of microalbuminuria, we measured albumin and creatinine concentration in overnight and morning urine of 125 diabetic outpatients. The overnight albumin excretion rate resulted in relation to morning albumin concentration and morning albumin/creatinine ratio. The sensitivity of this method of urine collection, compared to the overnight sample, was 55.5%, the specificity 96.6% and the predictive value 43% using, as a measure, the albumin concentration. These values improved by correcting albumin for creatinine concentration. Concerning high risk albuminuria (overnight excretion rate greater than 30 micrograms/min), we found a sensitivity and predictive value of the first morning collection highly improved by the albumin/creatinine ratio. It is concluded that the first morning urine collection can be used in the diagnosis of microalbuminuria in diabetic patients, especially when we calculate the albumin/creatinine ratio. This simple and reliable method allows the identification of microalbuminuric subjects and of the patients at risk to develop clinical nephropathy with a good sensitivity.

Effects of somatostatin on the behaviour of thromboxane B2 and beta-thromboglobulin in type I diabetes.

Pharmacological studies have shown that the addition of somatostatin to insulin promotes a more rapid recovery from diabetic ketoacidosis. However, contradictory results have been reported concerning the action of somatostatin on platelet function, frequently deranged in diabetes. Therefore the plasma levels of thromboxane B2, a stable metabolite of proaggregatory thromboxane A2 and of beta-thromboglobulin, a marker of platelet activation, were studied in 9 control subjects and in 13 insulin-dependent diabetic patients before and during somatostatin injection, administered as an initial 250 micrograms iv bolus followed by infusion of 300 micrograms over 3 h. In both groups, after somatostatin infusion thromboxane B2 and beta-thromboglobulin levels showed, respectively, a progressive fall and an increase up to the second hour. Over the next hour thromboxane B2 increased and beta-thromboglobulin decreased but their levels did not return to basal values. During this experiment beta-thromboglobulin plasma values in diabetic patients did not differ from those of control subjects. In contrast, thromboxane B2, decreased in relation to pharmacological treatment, maintained elevated levels. Our data, however, demonstrate that the dose of somatostatin used, produced in the diabetic patients a normal fall of thromboxane B2 in terms of percentage of base-line values, but increases of beta-thromboglobulin lower than in control subjects. It is suggested that platelet function should be evaluated when somatostatin is used in the treatment of poorly controlled type I diabetes.

Effects of somatostatin on the behavior of thromboxane B2 and B-thromboglobulin in type 1 diabetes.

Somatostatin, as an adjunct to insulin in the treatment of poorly controlled type 1 diabetes, has been recently suggested. However, some authors, after injection of the polypeptide, detected a reduction in number and aggregation of platelets, others instead, reported a proaggregatory effect of the drug. To answer these questions, the plasma levels of proaggregatory thromboxane A2 and of B-thromboglobulin, marker of the platelet activation, were studied in nine control subjects and in thirteen insulin dependent diabetic patients before and during the endovenous injection, for three hours, of somatostatin (250 micrograms in bolus followed by infusion of 100 micrograms/h). In both groups, 30 min after the infusion of somatostatin, a fall of thromboxane B2, stable metabolite of thromboxane A2 and an increase of B-thromboglobulin were respectively observed. Their greatest figure was reached after 120 min and their levels did not return to basal values within the end of the observation. In diabetics, during the infusion of somatostatin, thromboxane B2 presented normal percentual falls while B-thromboglobulin showed increases which were lower than controls. In conclusion, the effect of somatostatin implied in the relative lower increase of B-thromboglobulin, seems connected to the precedent continuous activation of circulating platelets, the one, responsible for the decrease of thromboxane B2, instead, seems linked to a direct action of somatostatin, independently on the deranged metabolic conditions found in diabetic patients.

[Evaluation of the antihypertensive effect and tolerability of nadolol administered alone or in association with bendroflumethiazide]. / Valutazione dell'efficacia anti-ipertensiva e della tollerabilità del nadololo somministrato da solo o in associazione a bendroflumetiazide.

The anti-hypertensive action and tolerability of single daily doses of 80 mg nadolol, or 80 mg nadolol and 5 mg bendroflumethiazide were assessed in 30 subjects with mild or moderate hypertension. In both experiments a significant reduction in arterial pressure was observed, while no undesirable effects were noted. The association of nadolol and bendroflumethiaxide not merely proved to have a greater anti-hypertensive effect than treatment with the beta-blocking agent alone, but also led to the normalisation of blood pressure values in a higher percentage of hypertensive subjects than when nadolol alone was administered. This particular drug combination is thus the treatment of choice for most patients with hypertension. The fact that the beta-blocking agent and the diuretic can be administered in a single daily dose clearly enhances the patient's compliance with the prescribed treatment.

[Effects of ticlopidine on the plasma levels of beta-thromboglobulin and thromboxane B2 in types 1 and 2 diabetics]. / Effetti della ticlopidina sui valori plasmatici della beta-tromboglobulina e del trombossano B2 rilevati in diabetici tipo 1 e 2.

11 insulin-dependent and 19 non insulin-dependent diabetics with varying degrees of metabolic compensation and with high plasma levels of beta-thromboglobulin and thromboxane B2 were selected. Depending on the type of diabetes and the degree of glycaemia, control plasma levels of beta-thromboglobulin and thromboxane B2 were progressively lower after 14, 28 and 42 days of treatment with ticlopidine (500 mg/per day orally), than those encountered at the start of the study. It is concluded that ticlopidine influences plasma levels of beta-thromboglobulin and thromboxane B2 independently of the type and degree of metabolic compensation in diabetes mellitus.

[Determination of glycosylated albumin in controls and in diabetics by affinity chromatography with phenylboronic acid]. / Determinazione dell' albumina glicosilata, in soggetti di controllo e in diabetici, mediante cromatografia di affinita' con acido fenilboronico.

The determination of glycosylated albumin was performed in 19 diabetic patients and in 16 control subjects, by means of chromatographic separation on columns of phenilboronic acid, immobilized by agarose gel. The interference with free glucose was eliminated by serum gel filtration on sephadex G 25 columns. The results demonstrated that glycosylated albumin values, obtained by affinity chromatography, discriminate diabetic by non-diabetic subjects and significantly correlate with glycosylated proteins levels, taken by colorimetric method with thiobarbituric acid. The chromatographic technique resulted in a more simplified way than colorimetric method and has shown to be sensitive to significant increases in "in vitro" glycosylation. Moreover it lasts less than the other technique and its variation coefficient is extremely low. In conclusion it represents a progress in the routine determination of glycosylated albumin.

Non-enzymatic glycosylation of urinary proteins in type 1 (insulin-dependent) diabetes: correlation with metabolic control and the degree of proteinuria.

In 18 control subjects and in 41 Type 1 (insulin-dependent) diabetic patients (13 with normal proteinuria, group A; 15 with microproteinuria, group B; and 13 with clinical proteinuria, group C), mean blood glucose, glycosylated haemoglobin and non-enzymatic glycosylated serum and urinary proteins, expressed as 5-hydroxymethylfurfural (5-HMF), were measured. In each group of diabetic patients, the levels of mean daily blood glucose, glycosylated haemoglobin and serum 5-HMF/mg protein were higher than in the control subjects. The urinary 5-HMF/mg proteinuria and the urinary/serum 5-HMF concentration ratio values were raised in group A and reduced in groups B and C. Moreover, they showed a negative correlation with 24-h urinary protein excretion in the control subjects and in each group of diabetic patients. The urinary 5-HMF/day in groups A, B and C was greater than in the control subjects. The urinary 5-HMF/day did not correlate with the mean daily blood glucose levels and, only in group A, did it correlate with serum 5-HMF and glycosylated haemoglobin. This suggests that, in this group, functional factors result in the increased renal elimination of 5-HMF and, therefore, of non-enzymatically glycosylated proteins. However, in the other groups of patients, this elimination depends on the degree of proteinuria.

[Clinical study of the therapeutic effect of Mefoxine]. / Osservazioni cliniche sull'azione terapeutica del Mefoxin.

The therapeutic efficacy of cefoxitin was studied in 15 patients with pulmonary or urinary infections, after other unsuccessful antibiotic treatment. The drug determined a total regression of clinical picture within 10 days of therapy. Our results show that brief periods of treatment are sufficient in order to obtain recovery and to avoid selection of resistant germs. Patients treated with cefoxitin did not present any intolerance. The conclusion is drawn that "Mefoxin" is useful in patients affected by infections resistant to common antibiotics.

[Thromboxane, beta-thromboglobulin and the degree of blood sugar control in type 1 diabetes mellitus]. / Trombossano, beta-tromboglobulina e grado di controllo glicemico nel diabete mellito tipo 1.

Plasma concentrations of beta-thromboglobulin (B-TG) and of Thromboxane B2 (TxB2) were found to be increased in diabetics but their values didn't result in relation to simultaneous fasting glycemia. The aim of this study was to elucidate if the B-TG and TxB2 levels were correlated with the indexes of medium and long-term diabetes control, namely non-enzymatic glycosylation of serum proteins (GSP) and irreversibly glycosylated hemoglobin, stable (S) HbA1. Therefore the behaviour of B-TG, TxB2, glycemia, GSP, T-HbA1 (stable and labile) and S-HbA1 were determined in 37 type 1 diabetics without any apparent vascular complication. All these parameters, except S-HbA1, were studied also in 8 ketoacidotic diabetic out patients before and during the recovery of metabolic control. Glycemia was assayed by the method of Trinder; B-TG and TxB2 were determined by radio-immunoassay. GSP was measured by chemical procedure using thiobarbituric acid (TBA test). The concentration of HbA1 was performed before and after incubation of erythrocytes for 6 h at 37 degrees C in saline to evaluate T and S-HbA1. In the out-patients B-TG and TxB2 were found to be correlated only with GSP. During the recovery of glycemic control a progressive decrease in the levels of T-BG and TxB2 was observed. We conclude that in vitro platelet activation i.e. B-TG and TxB2 levels, stable metabolite of proaggregatory TxA2, are deranged in relation to medium term glycemic disturbance rather than to short-term glucose fluctuations.

[Correlation between beta-thromboglobulin and metabolic compensation in diabetes type I]. / Correlazione fra beta-tromboglobulina e compenso metabolico del diabete tipo I.

In 37 type I diabetic out-patients without any apparent vascular complication and in 9 diabetics with ketoacidosis we have studied the behavior of beta-TG and of glycemia, GSP and HbA1 which are indexes of the short, medium and long-term glycemic control, respectively. In the out-patients beta-TG was found to be correlated only with the GSP. During the recovery of glycemic control, a progressive decrease in the level of beta-TG was found. Therefore, we conclude that also the metabolic derangement of diabetes takes part in the platelet activation.