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R Reitano

Publications and source records attributed to R Reitano.

18 recordsLinked to original sources
PubMed2005

A matrix-assisted laser desorption/ionization mass spectrometry study of the non-enzymatic glycation products of human globins in diabetes.

The molecular species present in globins from healthy and diabetic subjects with and without chronic complications have been analyzed by matrix-assisted laser desorption/ionization mass spectrometry. The technique demonstrated the presence of glycated and glyco-oxidated species of both alpha- and beta-globins. Their abundances show a good linear relationship with respect to HbA1c values and with the mean daily plasma glucose levels over the 6 weeks preceding the investigation. Interestingly, slightly different behaviour is observed in the data from patients with and without chronic complications; the plots of HbA1c vs. the abundance of glycated and glyco-oxidated species show different slopes and different intercepts with the y-axis. To investigate this aspect the mean abundances of glyco-oxidated species from healthy subjects and from diabetic patients with and without complications were calculated. Higher values were found for the two last sets of samples, but no significant difference was found between them. These data could indicate different individual proclivities to oxidation and/or different oxidation kinetics related to behavioural and environmental factors.

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PubMed2005

Pentosidine plasma levels and relation with metabolic control in diabetic patients.

Levels of plasma pentosidine, a well-known AGE, were measured in type 2 diabetic patients in varying states of metabolic control to verify possible relationships between this parameter and traditional metabolic control parameters such as HbA1c and plasma glucose levels. At baseline, mean values of fasting plasma glucose, HbA1c and pentosidine were significantly higher in diabetic patients than those of controls, confirming patients' poor glycemic control. After ten months, patients with good metabolic control achieved showed near-normal HbA1c levels and reduced but not normalized pentosidine levels. Significant differences were found in the mean percentage decrease in the parameters. Regarding linear correlation, HbA1c levels only showed a positive relationship with plasma glucose values at baseline. Patients affected by chronic complications showed higher levels of pentosidine than those without complications. Thus, pentosidine plasma levels may be used to evaluate very long-term metabolic control in diabetic patients. In addition, a period of ten months of acceptable metabolic control is not enough to normalize pentosidine levels in diabetics, thus emphasizing the need for a longer period of improved metabolic control to reduce both this parameter and the burden of chronic diabetic complications.

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PubMed2005

Evaluation of glyoxal and methylglyoxal levels in uremic patients under peritoneal dialysis.

Advanced glycation end products (AGEs) accumulate in serum and tissues of patients with chronic renal failure, even in the absence of diabetes, and a different clearance of these species has been observed by hemodialysis and peritoneal dialysis (CAPD). Furthermore, it has been shown that not only AGE but also 1,2-dicarbonyl compounds are formed during heat sterilization of glucose-based peritoneal dialysis fluids. Therefore, we investigated the level of some AGEs (pentosidine and free pentosidine) and dicarbonyl compounds (glyoxal and methylglyoxal) in end-stage renal disease patients subjected to peritoneal dialysis. Samples (20 from healthy subjects, 16 from uremic patients before and after 12 h of peritoneal dialysis) were analyzed, and the plasma and dialysate levels of glyoxal, methylglyoxal, pentosidine, and free pentosidine were determined. In plasma of uremic patients, mean values of pentosidine showed a small decrease after dialysis and were always higher than those of healthy control subjects. An analogous trend was observed for free pentosidine. In the case of peritoneal dialysate, no pentosidine and free pentosidine were found at time zero, whereas both compounds were detected after 12 h of dialysis. Glyoxal and methylglyoxal mean levels showed a decrease in plasma after dialysis even if their values were always higher than those of healthy control subjects. Surprisingly, an analogous trend was observed also in dialysate. These results might indicate that glyoxal and methylglyoxal already present in the dialysis fluid react with the peritoneal matrix proteins, accounting for the gradual loss of peritoneal membrane function that is often observed in patients subjected to CAPD for a long time.

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PubMed2005

Advanced glycation end products/peptides: an in vivo investigation.

Advanced glycation end products/peptides (AGE/peptides) originate by in vivo enzymatic digestion of nonenzymatically glycated proteins, which are produced by reaction of glucose with primary amino groups present in the protein chain following the Maillard pattern. AGE/peptides are highly reactive species and can interact with tissue and circulating proteins, leading to tissue modification and impaired protein functionality. Serum levels of AGE/peptides are reported to be particularly high in diabetes (in terms of higher production) or in end-stage renal disease (in terms of accumulation). For these reasons, their structural identification is of high interest, giving information on their relationship with the pathological state and allowing the design of possible therapeutic interventions. We report here some preliminary results obtained by liquid chromatography/electrospray ionization/mass spectrometry (LC/ESI/MS) and matrix-assisted laser desorption ionization MS (MALDI-MS) investigations carried out on the low-molecular-weight serum peptide fraction from 10 healthy subjects, 10 patients with poorly controlled diabetes, and 10 patients with end-stage nephropathy.

Amines↗
PubMed2004

The complexity of non-enzymatic glycation product sets of human globins.

AIMS/HYPOTHESIS: Recently an individual variability in the relationships between mean blood glucose levels and HbA1c has been observed among diabetic patients. The aim of this study was to provide an accurate description and evaluation of glycated and glyco-oxidated globins from diabetic subjects and their relationship with HbA1c and plasma glucose values. METHODS: We studied 20 type 2 diabetic and 10 healthy subjects. Plasma samples were analysed by matrix-assisted laser desorption ionisation mass spectrometry. RESULTS: The presence of glycated and glyco-oxidated species of both alpha and beta globin was demonstrated. Values for these showed a good linear relationship with HbA1c values and the mean daily plasma glucose values for the 6 weeks preceding the investigation. Trends differed according to whether patients had chronic complications or not, differences being seen in the slopes of the plots relating HbA1c to the abundance of glycated and glyco-oxidated species. CONCLUSIONS/INTERPRETATION: The data obtained are consistent with the concept that individuals have a different individual proclivity for oxidation and/or that different oxidation kinetics are related to behavioural and environmental factors. Our data are thus relevant to the analysis of phenotype differences in diabetic patients.

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PubMedDate not supplied

[Effects of hypoxia on the production of angiotensin converting enzyme in decompensated liver cirrhosis].

The high angiotensin-converting activity, in 13 of the 17 patients afflicted with hepatic cirrhosis, has been put in relation to the hypoxia influence. The insufficient cession of O2 seems to stimulate the enzyme activity, especially for the patients who simultaneously present low values of blood pseudo-cholinesterase. The AA think that this behaviour is to be ascribed to a deficiency of the hepatic proteic synthesis of vasoactive substances, such as the angiotensins.

Adult↗
PubMedDate not supplied

[Collagenous colitis. Morphologic and immunohistochemical study].

Collagenous colitis is a clinico-pathological entity characterized by chronic diarrhoeas and deposition of collagen beneath the epithelium surface of large bowel. We revised 265 endoscopy biopsy specimens of the large bowel from 198 consecutive patients with "aspecific chronic colitis". Morphometric study showed that were not significant differences among various tracts in the same patients regarding to the thickness of basament membrane. It was more than 11.9 +/- 0.49 mu only in 13 pts (6.6%), while it was 3.96 +/- 1.4 mu in the others. Immunohistochemistry study confirmed the normality of subepithelial basement membrane and the below deposition of the large quantity of collagen IV.

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