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Biomedical subjects

R Navalesi

Publications and source records attributed to R Navalesi.

At least 127 records · Page 7Linked to original sources
PubMed1988

Increased urinary excretion of digoxin-like immunoreactive substance by insulin-dependent diabetic patients: a linkage with hypertension?

Excretion of digoxin-like immunoreactivity (DLIS) was measured by RIA in timed overnight urine collections from 91 normotensive nondiabetic subjects and 104 normotensive insulin-dependent diabetic (IDDM) patients. The mean +/- SD DLIS excretion rate for the diabetic patients significantly exceeded that for the controls (73 +/- 41 vs 63 +/- 36 pg/min, P = 0.024). In both groups, the mean DLIS excretion rates for men were significantly higher (P = 0.0014, P = 0.006) than for women. In the controls, the DLIS excretion rate significantly correlated with the urinary excretion rate of creatinine (P less than 0.01), Na+ (P less than 0.05), and K+(P less than 0.05), and with the subjects' body weight (P less than 0.01), body mass index (P less than 0.05), and systolic blood pressure (P less than 0.05). In the diabetics, the DLIS excretion rate was significantly correlated with body weight (P less than 0.05) and with urinary excretion rates for albumin (P less than 0.01), creatinine (P less than 0.01), Na+ (P less than 0.05), and K+(P less than 0.05). Our data indicate that: (a) increased amounts of a cardiac glycoside-like substance (or a group of substances) are excreted in the urine of IDDM patients; (b) the urinary excretion of DLIS seems to depend on glomerular filtration rate and physiocochemical properties of glomerular membrane, as well as on subjects' body mass; and (c) because cardiac glycoside-like substances may increase peripheral vascular resistance, increased urinary excretion of DLIS by IDDM patients may indicate a tendency to develop hypertension.

Adult↗
PubMed1988

Albuminuria estimated from proteinuria in diabetics. Is it a real alternative in clinical practice?

While proteinuria detectable by dip-sticks is the hallmark of overt diabetic nephropathy, urinary albumin excretion (UAE) above normal but Albustix-negative (so-called microalbuminuria) is the main characteristic of the preproteinuric phase of the diabetic renal disease. Reliable measurement of UAE requires very sensitive and accurate methods, such as radioimmunoassay (RIA), which, however, are not suitable for routine UAE analysis. The Coomassie Brilliant Blue dye binding method has been suggested to be a simple and economical way of indirectly measuring albuminuria in diabetic patients. In the present paper, we compared the chemico-clinical characteristics of a RIA method with those of the Coomassie dye binding method, in order to verify if it is really possible to calculate albuminuria from proteinuria (and vice versa) by a simple linear regression equation, as previously suggested. The RIA has shown a better sensitivity and accuracy in comparison to the dye binding method. Our study suggests that there is not a linear relationship between proteinuria and albuminuria in diabetic patients. Indeed, the ratio between the total proteinuria, as measured with the dye method, and the albuminuria, as measured by a specific and sensitive RIA, varies greatly in diabetic patients with or without glomerular nephropathy. While the dye binding method appears the best procedure for the assay of total microproteinuria, since it is precise, cheap and feasible, the RIA, due to its high sensitivity and specificity, is more suitable for early and accurate detection of microalbuminuria, as well for the close follow-up of subjects at risk of developing overt diabetic nephropathy.

Albuminuria↗
PubMed1988

Excretion of digoxin-like immunoreactivity in urine of normal subjects: correlations with excretion of creatinine and electrolytes.

To verify whether there is a variation in the 24-h urinary excretion of digoxin-like immunoreactivity (DLIS) in humans, we studied 18 normal adults, who collected their urines for 24-h in several portions. We then measured DLIS (by means of a sensitive RIA method), creatinine, sodium, and potassium concentrations in the urine samples. The mean urinary excretion rate for DLIS in the complete 24-h collection was 84.8 (SD 31.3) pg/min. The mean DLIS urinary excretion rate calculated for overnight collections was significantly lower than those of afternoon collections (P less than 0.01) and the 24-h collection (P less than 0.05). Significant positive correlations were found between urinary DLIS and excretion rates for creatinine (r = 0.347, P = 0.0016), Na+ (r = 0.232, P = 0.038), and K+ (r = 0.323, P = 0.003), respectively. Our data suggest that urinary excretion of DLIS is higher during "active" hours of the day, especially in the afternoon, than at rest, during the night.

Adult↗
PubMed1987

Clinical and metabolic study of a new pill containing 20 mcg ethinylestradiol plus 0.150 mg desogestrel.

The clinical and metabolic effects of a short-term treatment with a combination contraceptive pill containing 0.150 mg desogestrel and 20 mcg ethinylestradiol were evaluated in a group of 17 healthy women. In spite of the low estrogen content, the pill exerted a good cycle control and the incidence of irregular bleedings was low. The minor side effects commonly associated with oral contraceptive (OC) use rarely occurred, and an improvement of premenstrual symptoms was reported during pill intake. As for the different biochemical parameters tested, the formulation induced a significant increase of fibrinopeptide A (FPA) plasma levels. However, the resulting increase of peptide was lower than that induced by pills containing 30 mcg ethinylestradiol. No significant modifications of plasma total cholesterol (T-CH) and low-density lipoprotein cholesterol (LDL-CH) were observed, while triglycerides (TG), high-density lipoprotein cholesterol (HDL-CH) concentrations and the HDL-CH/LDL-CH ratio significantly increased. A significant increase of apolipoproteins AI (Apo AI) and apolipoproteins AII (Apo AII) concentrations was also observed. Moreover, the pill did not alter fasting insulin and glucose levels and their response to an oral glucose tolerance test (OGTT). It may be concluded that this new formulation can be considered acceptable for clinical use, mainly in consideration of the minor or no changes in the biochemical parameters regarded as risk factors for venous and arterial diseases.

Adult↗
PubMed1987

Inappropriate growth hormone response to luteinizing hormone-releasing hormone in diabetes mellitus.

We randomly administered luteinizing hormone-releasing hormone (LHRH) or thyrotropin releasing hormone (TRH) (25 micrograms and 200 micrograms, respectively, as a bolus), to 16 diabetic male subjects (9 type I, 7 type II) and to 9 healthy male controls in two different mornings. While GH in the basal state was similar in type I, type II, and normal subjects, LHRH administration surprisingly evoked a significant GH release in 7 (5 type 1, 2 type II) diabetic patients. GH-responders had higher glycated hemoglobin than non-responders (11 +/- 1 nu 8.3 +/- 0.5%) but superimposable fasting and intratest average glucose levels. Only one patient among the GH-responders to LHRH showed a GH release also after TRH. These data support the hypothesis that GH secretion in diabetes, especially when poorly controlled, is abnormal.

Blood Glucose↗
PubMed1987

Plasma biguanide levels are correlated with metabolic effects in diabetic patients.

Metabolic abnormalities occur in biguanide-treated diabetic patients. We investigated the relationship between plasma metformin and phenformin concentrations and metabolic effects. Drug levels were measured in 37 type II diabetic patients by HPLC. The method was sensitive, specific, and linear over a wide range of drug concentrations. Metformin and phenformin values ranged from 236 to 718 ng/ml and from 28 to 114 ng/ml, respectively. The plasma metformin level was correlated with triglycerides (r = -0.55; P less than 0.05) but not with drug dosage, plasma glucose, HbA1, creatinine, creatinine clearance, lactate, pyruvate, lipid, and clinical parameters. Plasma phenformin concentrations correlated with lactate (r = 0.49; P less than 0.05) and HbA1 (r = 0.50; P less than 0.05) but not with drug dosage, parameters of diabetes control, creatinine, creatinine clearance, pyruvate, and clinical parameters. The clinical usefulness of this HPLC method, the evidence that the increase of lactate is related to the circulating phenformin levels, and the demonstration that the metformin effect on triglyceride metabolism is correlated to plasma drug levels are the positive findings of this work.

Aged↗
PubMed1987

Effect of growth hormone-releasing hormone and clonidine on growth hormone release in type 1 diabetic patients.

We administered growth-hormone releasing hormone (GHRH), clonidine or thyrotropin-releasing hormone (TRH) as intravenous boli each in three different randomized mornings to nine well-controlled Type 1 diabetic men and to six age-matched healthy men who served as controls. GHRH and clonidine evoked a prompt and brisk GH release both in diabetic and in control subjects with no significant difference being evident between the two groups. Only one diabetic subject showed a paradoxical GH release after TRH when he was under long-term poor metabolic control. These results indicate that in insulin-dependent patients with good control of the metabolic disease the response of somatotropes to pituitary- or central nervous system-directed stimuli is normal. These data are supportive of the idea that altered GH secretion in Type 1 diabetes rather than reflecting a primary hypothalamic and/or pituitary alteration may be a state-dependent phenomenon related to the metabolic state of the disease.

Adult↗
PubMed1987

Effects of a low-phosphorus, low-protein diet supplemented with essential amino acids and keto analogues on 'overt' diabetic nephropathy.

In this paper we studied the effects of a low-protein, low-phosphorus supplemented diet in 8 type I diabetics with 'overt' diabetic nephropathy and mild or severe renal insufficiency. We examined the following parameters: the rate of decline of creatinine clearance, the urinary protein loss, the total serum protein, the daily insulin requirement, the serum fasting glucose, the pattern of serum lipids (serum total cholesterol, HDL cholesterol and serum triglycerides), the mean blood pressure and body weight. The rate of decline of creatinine clearance decreased monthly from 1.48 +/- 0.20 ml/min during a previous 15.6-month period of unrestricted protein diet (UPD), to 0.13 +/- 0.3 ml/min during the 11.4 months on the supplemented diet (SD). The mean blood pressure did not differ during UPD (130.9 +/- 7.0 mmHg) and during SD (128.1 +/- 1.6 mmHg). Urinary protein loss significantly decreased on SD, and total serum protein increased. The daily insulin requirement and the serum fasting glucose levels significantly decreased on SD. Serum cholesterol was lower during SD than during UPD, while serum HDL cholesterol and serum triglycerides were not significantly modified. In some patients the body weight decreased on SD as a consequence of the disappearance of edema. In conclusion, on the basis of these preliminary observations, the SD slows the progression of renal failure and seems to exert several beneficial and no unwanted side-effects in renal failure of type I diabetics.

Adult↗
PubMed1987

Circulating lipid levels and severity of diabetic retinopathy in type I diabetes mellitus.

Plasma lipid levels have been proposed as probable risk factors of diabetic retinopathy. To clarify this question, we evaluated the apolipoprotein levels in 68 type I diabetic patients (39 +/- SD 14 years; duration of diabetes 13 +/- SD 8.4 years). By the analysis of fluorescein angiography we have classified diabetic retinopathy as follows: absent retinopathy (AR, n = 23), minimal retinopathy (MR, n = 16), exudative retinopathy (ER, n = 15), proliferative retinopathy (PR, n = 14). For all patients we measured: total, LDL- and HDL-cholesterol (T-CH, LDL-CH, HDL-CH), apolipoproteins A and B (Apo A and B), fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1). The mean age of the patients with ER (47 +/- SD 14 years) was greater than those with MR (36 +/- SD 15 years) or AR (33 +/- SD 13 years) (p less than 0.05). Significant differences within groups were not found for relative body weight, daily insulin dose, FPG, HbA1% (analysis of variance, ANOVA). The groups differed between each other with regard to T-CH, LDL-CH and HDL-CH/LDL-CH ratio (T-cholesterol: AR 186 +/- SD 34, MR 191 +/- SD 32, ER 212 +/- SD 52, PR 215 +/- SD 41 mg/dl; LDL-cholesterol: AR 124 +/- SD 28, MR 122 +/- SD 18, ER 148 +/- SD 38, PR 145 +/- SD 33 mg/dl; HDL/LDL-cholesterol ratio: AR 0.38 +/- SD 0.1, MR 0.35 +/- SD 0.1, ER 0.30 +/- SD 0.1, PR 0.29 +/- SD 0.1). The total-CH levels increased and HDL-CH/LDL-CH ratio decreased along with the severity of the retinopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Intracellular insulin processing is altered in monocytes from patients with type II diabetes mellitus.

We studied total cell-associated A14-[125I]insulin radioactivity (including surface-bound and internalized radioactivity), insulin internalization, and its intracellular degradation at 37 C in monocytes from nonobese type II untreated diabetic patients (n = 9) and normal subjects (n = 7). Total cell-associated radioactivity was decreased in diabetic patients [2.65 +/- 1.21% (+/- SD) vs. 4.47 +/- 1.04% of total radioactivity; P less than 0.01]. Insulin internalization was also reduced in diabetic patients (34.0 +/- 6.8% vs. 59.0 +/- 11.3% of cell-associated radioactivity; P less than 0.01). Using high performance liquid chromatography six intracellular forms of radioactivity derived from A14-[125I] insulin were identified; 10-20% of intracellular radioactivity had approximately 300,000 mol wt and was identified as radioactivity bound to the insulin receptor, and the remaining intracellular radioactivity included intact A14-[125I]insulin, [125I]iodide, or [125I]tyrosine, and three intermediate compounds. A progressive reduction of intact insulin and a corresponding increase in iodine were found when the incubation time was prolonged. Intracellular insulin degradation was reduced in monocytes from diabetic patients; intracellular intact insulin was 65.6 +/- 18.1% vs. 37.4 +/- 18.0% of intracellular radioactivity (P less than 0.01) after 2 min and 23.6 +/- 22.3% vs. 3.9 +/- 2.3% (P less than 0.01) after 60 min in diabetic patients vs. normal subjects, respectively. In conclusion, 1) human monocytes internalize and degrade insulin in the intracellular compartment in a stepwise time-dependent manner; and 2) in monocytes from type II diabetic patients total cell-associated radioactivity, insulin internalization, and insulin degradation are significantly reduced. These defects may be related to the cellular insulin resistance present in these patients.

Aged↗
PubMed1987

Long-term therapy with biosynthetic human insulin: importance of short-acting/intermediate-acting insulin ratio on determining efficacy of treatment.

This report describes the efficacy of biosynthetic human insulin (BHI) in long-term (one year) therapy of type I diabetic patients previously treated with conventional insulins. The results were compared with those obtained in a group of diabetic patients kept on their usual treatment. In the latter, fasting plasma glucose, HbA1, insulin dose and relative proportions of insulin formulations remained constant throughout the study. In patients switched to BHI, hypoglycaemic episodes occurred during the first week of treatment and fasting plasma glucose was higher than basally at the first two visits (7th and 30th days). Both hypoglycaemia and high fasting plasma glucose were avoided by reducing the amount of short-acting insulin and increasing that of intermediate-acting insulin, so that the short-acting/intermediate-acting insulin ratio was significantly lower during BHI therapy, although the total daily insulin dose remained unchanged. HbA1 levels remained fairly constant throughout the study. It was concluded that in order to achieve full clinical efficacy of BHI, it is important to modify the proportions of short- and intermediate-acting insulin preparations accurately when switching patients from conventional insulin to biosynthetic human insulin.

Adult↗
PubMed1987

Prevalence and type of sexual dysfunctions in diabetic males: a standardized clinical approach.

The diagnosis of sexual dysfunctions (SD) in diabetic male patients is usually based on interviews about the sexual behavior of the patients themselves. The absence of a standardized procedure may explain the discrepancies in the prevalence reported in previous papers. In this work, we show a rational procedure to assess the presence and the type of SD in a group of 128 diabetic men. By means of an appropriate questionnaire, SD were pointed out in 40% of insulin-dependent diabetics (IDD) and 52% of non-insulin-dependent diabetic patients (NIDD). Among the patients with SD, 28% had organic impotence, 11% psychogenic impotence and 8% reduction of libido. IDD with SD were older (p less than 0.01) and with a longer duration of diabetes (p less than 0.02) than IDD without SD. NIDD with and without SD had similar ages and known duration of diabetes. Both in IDD and in NIDD, the prevalence of SD was not affected by the quality of short-term metabolic control. In the patients in whom it was studied by a different technique, the predominant cause of organic impotence (76%) was a damage of parasympathetic nervous system, as evaluated by non-invasive tests. In 12% of the cases with organic impotence, a reduced penile flow alone was observed, while hormonal parameters were similar in patients with and without organic impotence.

Adult↗
PubMed1987

A sensitive high performance liquid chromatographic method for determining small amounts of glycosylproteins.

We developed a simple isocratic high performance liquid chromatography (HPLC) method for the quantitative determination of 5-hydroxymethyl-2-furfuraldehyde (5-HMF) liberated by mild hydrolysis of small amounts of glycosyl proteins. The absorbance of hydrolysate components after HPLC separation was recorded at 280 nm. To detect substances possibly interfering with the 5-HMF peak we always recorded the ratio of the peak heights A280 nm/A254 nm which was a constant value of 4.4. For each sample the blank was obtained by reduction with NaBH4 before hydrolysis with oxalic acid 1 mol/l. The best NaBH4/protein ratio was found to be 4 mg/mg. With this method we measured the nonenzymatic glycosylation (glycation) as 5-HMF in samples with a protein concentration as low as 0.8 mg/ml. 5-HMF produced per milligram of protein was independent from protein concentration for a wide range (0.8-10 mg/ml). The mean coefficient of variation for within assay and between precision was 6.8 and 11.6%, respectively. The 5-HMF measured on plasma proteins from normal subjects (n = 7) was 0.16 +/- 0.04 nmol/mg. Protein from insulin-dependent diabetic patients was 0.31 +/- 0.07 nmol/mg. With this method we succeeded in detecting an excessive glycation of platelet membrane proteins in 13 type-I diabetic patients.

Blood Platelets↗
PubMed1987

The clinical usefulness of glycated hemoglobin in monitoring diabetes mellitus: a long-term study.

To assess the long-term clinical usefulness of measuring glycated hemoglobin (Hb A1), we carried out a two-year longitudinal study involving 234 diabetic patients (116 males, 118 females; 139 with type I diabetes mellitus, 95 with type II). Hb A1 values correlated significantly (p less than 0.001) with a score index based on plasma glucose in a specimen collected after overnight fasting, and urinary glucose, and ketones in a 24-h specimen. However, we found that one of every three well-controlled patients (both type I and II subjects) had high values for Hb A1. Among poorly controlled patients, only those with "brittle" diabetes had good values for Hb A1.

Adolescent↗
PubMed1986

Relation of glucose tolerance to complications of pregnancy in nondiabetic women.

An increase in fetal and maternal complications has been documented in cases of gestational diabetes, but the glucose levels that predict an increased risk have not been clearly defined. We evaluated the frequency of several neonatal complications (macrosomia, congenital anomalies, perinatal mortality, and prematurity) and maternal complications (toxemia, cesarean section, or both) in relation to glucose tolerance in 249 women in the third trimester of pregnancy. None of the women had previous evidence of diabetes, and all had normal results on an oral glucose-tolerance test, according to accepted criteria. On the basis of their two-hour plasma glucose levels, women were divided into three groups: A (glucose less than 100 mg per deciliter), B (glucose 100 to 119 mg per deciliter), and C (glucose 120 to 164 mg per deciliter). The higher two-hour plasma glucose levels were associated with a significant increase in the incidence of macrosomia (9.9, 15.5, and 27.5 percent in Groups A, B, and C, respectively), congenital abnormalities (0.7, 3.5, and 5.0 percent), and toxemia, cesarean section, or both (19.9, 25.9, and 40.0 percent). A significant correlation between the infant's weight and the mother's two-hour plasma glucose level was also observed. These data indicate that even limited degrees of maternal hyperglycemia, which are currently considered to be within the normal range, may affect the outcome of pregnancy.

Birth Weight↗
PubMed1986

A14-[125I]monoiodoinsulin purified by different high-performance liquid chromatographic procedures and by polyacrylamide gel electrophoresis: preparation, immunochemical properties and receptor binding affinity.

Reversed-phase high-performance liquid chromatography (RP-HPLC) allows the rapid separation of A14-[125I]monoiodoinsulin directly from the iodination mixtures. It remains to be clarified, however, whether the RP-HPLC chromatographic conditions affect the properties of the purified tracer. In this study we prepared A14-[125I]insulin purified by polyacrylamide gel electrophoresis (PAGE) and by three different RP-HPLC mobile phases containing, respectively, ammonium acetate, sodium perchlorate and trifluoroacetic acid. The binding characteristics of all these tracers were examined using an insulin antiserum and insulin cell receptors. The specific radioactivity corresponded to the theoretical maximum for the RP-HPLC-purified tracers and was significantly lower for the PAGE-purified tracers. Significant differences were found in the binding of different tracers to the insulin antiserum: maximum binding ranged from 94 to 99% and was significantly lower for tracers purified by RP-HPLC eluents B and C; antiserum dilution giving 50% tracer binding was lower for tracers purified by RP-HPLC eluent B. The four insulin derivatives showed no difference in non-specific precipitation and in the affinity constant values calculated from the Scatchard analysis. No significant difference was found in the binding of the four insulin derivatives to the human-cultured IM-9 lymphocytes and to the human circulating monocytes. In conclusion, the present work demonstrates that the immunological properties of the A14-[125I]monoiodoinsulin purified by RP-HPLC may be partially affected by the composition of the mobile phase. In order to obtain a fully potent A14-[125I]insulin derivative and to have the possibility of comparing data from different laboratories, the chromatographic conditions must be taken into account.

Adult↗