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Biomedical subjects

D Fedele

Publications and source records attributed to D Fedele.

At least 55 records · Page 3Linked to original sources
PubMed1997

A highly specific method for the characterization of glycation and glyco-oxidation products of globins.

A new method, based on matrix-assisted laser desorption/ionization (MALDI) measurements, has been developed for the evaluation of the glycation level of globins, a relevant parameter for diabetes control. It shows high levels of reproducibility and specificity, allowing the different glycated and glyco-oxidized products of both alpha- and beta-globins to be distinguished. Such specificity is reflected in its possible diagnostic use not only for the control of diabetes, but also for the occurrence of 'oxidative stress'. The comparison, for the same samples, of the obtained MALDI data with the related HbA1c values, determined by a high performance liquid chromatographic method, allowed it to be established that HbA1c percentages are not, as usually retained, related to the simply glycated beta-globin, but to the whole pool of glycated and glyco-oxidized alpha- and beta-globins.

Adult↗
PubMed1997

Evaluation of IgG glycation levels by matrix-assisted laser desorption/ionization mass spectrometry.

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry has been employed for the evaluation of the glycation level of IgG from healthy subjects and also from well- and badly-controlled diabetic patients. The measurements have been performed on untreated plasma protein fractions. The data obtained have shown that a clear mass increase, originating from non-enzymatic glycation processes, is observed in the case of diabetic patients: for well-controlled ones it is in the range 512-1565 Da, while it becomes 827-4270 Da for badly-controlled diabetic patients. This approach indicates that MALDI mass spectrometry is a highly specific tool that can be employed in the metabolic control of diabetic patients and in studies relating the IgG glycation level to possible immunological impairment.

Aged↗
PubMed1997

Peripheral diabetic neuropathy. Current recommendations and future prospects for its prevention and management.

One-third of diabetic patients are affected by peripheral neuropathy (PDN) in which the main aetiopathogenetic mechanism seems to be the high blood and nerve glucose content. The results of some long term trials, such as the Diabetes Control and Complications Trial (DCCT) and Stockholm studies, showed clearly that the maintenance of near-normal blood glucose levels and haemoglobin (Hb)A1c below 7.5% with intensive insulin treatment represents the best approach to primary and secondary prevention of the late diabetic complications, including PDN. After 5 years of such treatment DCCT reported that the development of clinical PDN was reduced by 64%. On the other hand, various and important problems still exist in identifying an efficacious aetiological therapy for PDN. In fact, while on the basis of current knowledge we have 2 possibilities for treatment of the pain, optimisation of glycaemic and HbA1c values and correct use of tricyclic antidepressants, none of the various substances tested has proven to be efficacious for PDN. Gangliosides, aldose-reductase inhibitors, including tolrestat, gamma-linolenic acid, levacecarnine (acetyl-L-carnitine) and antioxidants, were all shown to be of poor efficacy and often with significant adverse effects. The maintenance of near-normal glycaemic equilibrium seems currently to be the best way not only to prevent PDN but also to treat it. In the near future more long term trials, with very clear inclusion and exclusion criteria for recruitment, are needed to assist in identifying an efficacious treatment for PDN.

Diabetic Neuropathies↗
PubMed1997

A multicenter study on the prevalence of diabetic neuropathy in Italy. Italian Diabetic Neuropathy Committee.

OBJECTIVE: The prevalence of neuropathy, a common complication of diabetes, was determined in diabetic patients recruited from 109 outpatient diabetes clinics in Italy. RESEARCH DESIGN AND METHODS: Neuropathy was diagnosed using the Diabetic Neuropathy Index (DNI), a standardized examination developed for use in the outpatient setting. A total of 8,757 diabetic patients were studied, 51.2% men and 48.8% women, with average and median ages of 56 and 58 years, respectively. RESULTS: Of the 8,757 patients, 32.3% had neuropathy, defined as a positive score of > 2 points on the DNI. A total of 2,033 (49.6% men and 50.4% women) were administered the Diabetic Neuropathy Score (DNS), the second component of the screening program, by a neurologist. This component consists of a quantitative neurological examination and nerve conduction studies that together provide a summated score. A total of 335 patients (16.5%) were not neuropathic, and 395 (19.4%) had borderline, 453 (22.3%) mild, 592 (29.1%) moderate, and 258 (12.7%) severe neuropathy. The concordance between a positive score on the DNI and a DNS indicating neuropathy was 83.5%. The severity of neuropathy increased with both age and disease duration. Of patients with neuropathy, 64.1% had an average age between 58 and 59 years with a disease duration between 12.4 +/- 8.4 years (mild neuropathy) and 15.6 +/- 9.7 years (severe neuropathy). CONCLUSIONS: Neuropathy is a common complication of diabetes and, in this study, was present in 32.3% of all patients. An increased awareness of the high prevalence of neuropathy can lead to early therapeutic intervention and possible prevention of later neuropathic complications, such as infection and foot ulcers.

Adult↗
PubMed1997

A protocol of screening of gestational diabetes mellitus.

We evaluated GDM frequency in the Padua area. 490 non-diabetic pregnant women were divided into group A (234), with at least one GDM risk factor, and group B (256), with no risk factors. Group A underwent this screening program with oral glucose challenge test (OGCT) and OGTT when OGCT was positive at 10-14th gestational week (gw), at 24-28th gw and at 30-34th gw. Group B underwent the same screening starting at 24-28th gw. 46.9% of the pregnant women had positive OGCT with higher frequency in group A (group A vs group B p < 0.01). GDM prevalence in all women was 10.8% with higher frequency in group A women (group A vs group B p < 0.01). The anticipation of the screening at the first trimester of pregnancy in group A women allowed early diagnosis of 11.6% of GDM. Regarding maternal and fetal outcome the only significative differences between GDM and non-GDM were prevalence of macrosomia and of cesarean sections.

Adult↗
PubMed1997

A study on lymphocyte subpopulations in diabetic pregnant women and their newborn.

We studied the lymphocyte subpopulations in 14 pregnant women with type 1 insulin-dependent diabetes mellitus (IDDM), mean age (+/- SD) 30 +/- 4 years, mean disease duration 12 +/- 5 years, in 14 with gestational diabetes mellitus (GDM) (mean age 33 +/- 6 years) and 21 matched healthy pregnant controls (C), when the subjects delivered, and in their newborn. The GDM and IDDM mothers show a significant increase (p < 0.05) of lymphocytes in comparison with C (GDM 1.83 +/- 0.5 x 10(9)/l, IDDM 1.6 +/- 0.68 x 10(9)/l, C 1.06 +/- 0.45 x 10(9)/l lymphocytes), which has repercussion on lymphocyte subpopulations absolute values. The newborn of GDM mothers have an increase of lymphocytes T-activated (0.6 +/- 0.3 vs 0.3 +/- 0.2%; p < 0.05) and a reduction of NK lymphocytes than C (8.9 +/- 9 vs 15.5 +/- 7.6%; p < 0.05). The newborn of IDDM mothers show a significant reduction of NK lymphocytes than C (10 +/- 6 vs 15.5 +/- 7.6%; p < 0.05). So in newborn of diabetic mothers there is a deficit of natural immunity at birth which has to be evaluated by follow-up study.

Adult↗
PubMed1996

An electrospray investigation on in vitro glycation of ribonuclease.

The in vitro reactions of RNase with different concentrations of glucose or fructose have been studied by means of electrospray mass spectrometry coupled with microcolumn high performance liquid chromatography. The results obtained have shown that, subsequent to the protein glycation, a series of cross-linking products are generated. Their molecular weights demonstrate that severe degradation processes of the proteic substrate takes place after the cross-linking process.

Amino Acid Sequence↗
PubMed1996

The in vivo glyco-oxidation of alpha- and beta-globins investigated by matrix-assisted laser desorption/ionization mass spectrometry.

Matrix-assisted laser desorption/ionization (MALDI) has been employed for the determination of molecular weights of alpha- and beta-globins obtained from blood samples of healthy and diabetic subjects. Glycated species, originating from the reaction of glucose with the proteins, are easily evident. The MALDI measurements allowed one to distinguish between simple glycation and glyco-oxidation processes of haemoglobin. In fact, together with the products arising from simple glucose condensation on the two proteins, compounds at different oxidation levels were evident. Due to its high specificity, MALDI must be considered a valuable tool for diagnosis in the diabetes field.

Diabetes Mellitus↗
PubMed1996

The in vitro glycation of lysozyme and the influence of buffer concentration investigated by mass spectrometry.

The non-enzymatic reactions between glucose or fructose with lysozyme, performed under pseudo-physiological conditions, have been studied by means of matrix-assisted laser desorption/ionization mass spectrometry. Phosphate buffer at concentrations of 0.05, 0.2 and 0.5 M has been employed. The formation of glycated proteins as well as of cross-linking products has been always observed. In the case of glucose, high phosphate buffer concentrations affect the glycation kinetics and promote the formation of cross-linking products. With fructose, such influence is moderate, the reaction kinetics being mainly influenced by the higher reactivity of the sugar.

Buffers↗
PubMed1996

An immunological and genetic study of patients with gestational diabetes mellitus.

The aim of the study was to evaluate the frequency of islet cell (ICA) and insulin (IAA) antibodies and of HLA antigen typing in a group of subjects diagnosed with gestational diabetes mellitus (GDM) in a screening-diagnostic program during pregnancy. ICA, complement-fixing (CF) ICA and other autoantibodies, absolute number and percentage of lymphocyte subpopulations, and HLA antigens were evaluated in 68 women with GDM and compared with those of matched controls. ICA were found in 2 (2.9%) and IAA in 1 (1.5%). Both ICA-positive women had CF-ICA; one of them was receiving insulin therapy. while the other was on a special diet. No correlations were found between ICA and IAA, nor between IAA and insulin treatment. As far as lymphocyte subsets were concerned, we found a significant increase in the absolute number of total and activated (CD3+HLA-DR+) T lymphocytes and a significant increase in the absolute number and percentage of suppressor/cytotoxic T lymphocytes (CD8) and NK lymphocytes (CD57) in GDM patients compared with normal pregnant controls. Concerning frequency for HLA A, B, C, DR antigens in the GDM population, only Cw7 was found to be significantly increased and A10 significantly decreased in comparison with controls. Our study suggests that GDM is a heterogeneous disorder in which few patients present with the immunologic and genetic markers of type 1 diabetes.

Adult↗
PubMed1995

Myocardial dysfunction and abnormal left ventricular exercise response in autonomic diabetic patients.

In diabetic patients, the pathophysiologic mechanisms of exercise-induced left ventricular (LV) dysfunction remain controversial. In this study, the role of myocardial contractility recruitment in determining an abnormal LV response to isometric or dynamic exercise has been investigated in 14 diabetic patients with autonomic dysfunction. Ischemic heart disease was excluded by the absence of LV wall motion abnormalities induced by isotonic and isometric exercise and by coronary angiography. Left ventricular and myocardial function were studied at rest, and during isometric and isotonic exercise, by two-dimensional echocardiography; moreover, recruitment of an inotropic reserve was assessed by postextrasystolic potentiation at rest and at peak handgrip. An abnormal response of LV ejection fraction to isometric (9/14) or to dynamic (8/14) exercise was frequent in study patients. In these patients, baseline myocardial contractility was normal, and the significant increase in ejection fraction by postextrasystolic potentiation indicated a normal contractile reserve (65 +/- 7% vs. 74 +/- 6%, p = 0.001). Nevertheless, the downward displacement of LV ejection fraction-systolic wall stress relationships during exercise suggests an inadequate increase in myocardial contractility. However, the abnormal ejection fraction at peak handgrip was completely reversed by postextrasystolic potentiation (67 +/- 6% vs. 58.1 +/- 10%, p = 0.008), a potent inotropic stimulation independent of the integrity of adrenergic cardiac receptors. A defective inotropic recruitment, despite the presence of a normal LV contractile reserve, plays an important role in deexercise LV dysfunction in diabetic patients with autonomic neuropathy.

Adult↗
PubMed1995

A new effective method for the evaluation of glycated intact plasma proteins in diabetic subjects.

The molecular weights of plasma proteins from healthy subjects and from patients with well-or badly-controlled diabetes mellitus have been determined by use of a matrix-assisted laser desorption ionization method, representing a highly accurate technique for the determination of the molecular weight of large biomolecules. Using this approach, different molecular weights of human serum albumin have been found for healthy (66,572-66,694 dalton) and diabetic (66,785-68,959 dalton) subjects. Such differences can be rationalized as being due to the different number of glucose molecules condensed on the protein and/or their further oxidation products; in the case of our diabetic patients this number is in the range of 1.4-14.8. The data show the high validity and specificity of the technique, which allows us to evaluate, without any protein degradation procedure, the number of glucose molecules condensed on a specific protein and ascertain the relationship of this number to the physiopathogenetic conditions of the subjects studied.

Adult↗
PubMed1995

Hypertension and non-insulin-dependent diabetes. A comparison between an angiotensin-converting enzyme inhibitor and a calcium antagonist.

The effects of the angiotensin-converting enzyme lisinopril were compared with those of the calcium antagonist nifedipine in 162 non-insulin-dependent diabetic hypertensive patients for a 24-week period. In 83 and 79 patients, respectively, lisinopril and slow-release nifedipine produced similar reductions in blood pressure (systolic/diastolic: -16/-13 mmHg supine and -14/-11 mmHg standing after lisinopril; -15/-12 mmHg supine and -14/-11 mmHg standing nifedipine). Fasting and post-prandial plasma glucose, glycosylated haemoglobin and plasma lipids appeared to be unaffected by either agent. Also, 28% of the patients on lisinopril and 30% of those on nifedipine presented microalbuminuria. Both drugs induced a reduction in the albumin excretion rate (AER). The geometric mean x:tolerance factor of the reduction in AER among the 23 microalbuminuric patients on lisinopril (-10.0 x:1.3 micrograms/min) was greater, though not significantly so, than that observed in the 26 on nifedipine (-0.9 x 1.2 micrograms/min). Moreover, lisinopril appeared to be better tolerated than nifedipine in our study population. Microalbuminuria is an important risk factor for cardiovascular mortality in non-insulin-dependent diabetic patients as well as in the general population. To what extent a reduction in the AER could ameliorate diabetic patients is, at present, unknown. Finally, both lisinopril and nifedipine showed a similar antihypertensive effect in these patients which was not associated with significant differences in plasma glucose, insulin or lipid concentrations. The clinical consequences of the insignificant differences in AER remain unclear.

Albuminuria↗
PubMed1995

Early involvement of central nervous system in type I diabetic patients.

OBJECTIVE: To investigate whether the asymptomatic involvement of the central and peripheral nervous systems may be an early complication of diabetes. RESEARCH DESIGN AND METHODS: We studied early impairment of the central and peripheral nervous system pathways in 15 type I diabetic patients with good metabolic control and short disease duration and in 10 healthy control subjects using a set of neurophysiological tests. RESULTS: Results in diabetic subjects showed 1) impairment of motor (7% and somatosensory (13%) pathways of the central nervous system, 2) impairment of motor and sensory conduction velocities (40-60%), and 3) normal values of the vibration perception threshold and cardiovascular autonomic tests. CONCLUSIONS: The damage is more evident in peripheral sites where hyperglycemia and aldose reductase pathways are more active. Instead, several episodes of hypoglycemia, which occur in type I diabetic patients in good metabolic control, may cause alterations of brain nervous cells.

Adult↗
PubMed1994

Matrix-assisted laser desorption/ionization capabilities in the study of non-enzymatic protein glycation.

Matrix-assisted laser desorption/ionization mass spectrometry has been successfully applied in the study of non-enzymatic glycation of different proteins. In the case of bovine serum albumin, glycated by in vitro experiments performed under pseudophysiological conditions, a clear increase in molecular weight is observed with respect to both glucose concentrations and incubation time. The in vitro glycation of ribonuclease with glucose and fructose shows some peculiar differences either in terms of the number of condensed sugar molecules or in terms of the reaction kinetics. The same approach, applied to plasma proteins of healthy and diabetic subjects, provides evidence for the occurrence of glycation of human serum albumin for the latter subjects.

Adult↗
PubMed1993

A study on in vitro glycation processes by matrix-assisted laser desorption ionization mass spectrometry.

The number of glucose molecules condensed on glycated bovine serum albumin have been easily determined by means of matrix-assisted laser desorption/ionization mass spectrometry. Measurements were carried out on samples from incubation of the protein with glucose at different concentrations (0.02 M, 0.2 M, 2 M and 5 M). A clear increase in molecular mass of BSA with respect to incubation time is detected. In contrast to what is observed with fluorescence, the plots of molecular mass increase vs. incubation time show the occurrence of a steady state, corresponding to the complete saturation of all the protein sites reactive against glucose. Comparison of fluorescence and molecular mass data reveals that some further reactions, different from condensation, must take place, which could be in principle either intramolecular or originated by reactivity of modified condensed glucose moieties vs. free glucose.

Glucose↗
PubMed1993

Lipoprotein abnormalities in well-treated type II diabetic patients.

OBJECTIVE: To investigate lipoprotein levels and composition in well-treated type II diabetic patients. RESEARCH DESIGN AND METHODS: Cholesterol and triglyceride levels were measured in plasma, VLDL, LDL, and HDL in 120 type II diabetic patients in good to fair metabolic control (HbA1c, 7.2 +/- 1.6%) and in 30 normal control subjects. ApoAI, AII, B, CII, CIII, and E levels in plasma were also determined. RESULTS: The diabetic patients have significantly higher levels of mean plasma cholesterol (5.85 vs. 5.43 mM, P = 0.03), LDL triglycerides (0.41 vs. 0.31 mM, P = 0.003), and HDL triglycerides (0.24 vs. 0.19 mM, P = 0.02), whereas total triglycerides, VLDL cholesterol and triglycerides, LDL cholesterol, and HDL cholesterol are not significantly different from normal control subjects. ApoB (150 vs. 135 mg/dl, P = 0.02) and apoCIII (10.6 vs. 8.4 mg/dl, P = 0.01) are significantly higher in diabetic patients compared with control subjects. No significant differences are observed in all the parameters among diabetic patients treated with diet only, sulphonylurea, sulphonylurea plus biguanides, or insulin. Body weight is significantly related to VLDL lipids. The VLDL triglycerides are inversely related to the HDL cholesterol in both diabetic patients and control subjects. The VLDL triglycerides are directly related to the HDL triglycerides only in diabetic patients. No other lipid or lipoprotein parameters are significantly related to body weight or metabolic control. CONCLUSIONS: Type II diabetic patients in good to fair metabolic control are characterized by minor alterations of the plasma lipids, but LDL and HDL triglycerides, apoB, and apoCIII are increased, thus indicating that the lipoprotein composition is altered, possibly because of an abnormal triglyceride metabolism and/or lipid transfer activity.

Aged↗