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Biomedical subjects

R Colombo

Publications and source records attributed to R Colombo.

At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

Role of red cell sorbitol as determinant of reduced erythrocyte filtrability in insulin-dependent diabetics.

Erythrocyte deformability measured as filtration index is clearly diminished in diabetics, thus possibly contributing to diabetes-associated microvascular complications. Moreover, the erythrocyte sorbitol level in IDD is clearly higher than that of non-diabetics, suggesting an alteration in the polyol pathway as possible determinant of diabetes-associated complications. Following this line of research, intracellular sorbitol as well as glucose, inositol, galactitol, mannitol and 2,3-diphosphoglycerate have been studied in 21 diabetics and in 14 controls matched for age and sex. In addition to confirming the high levels of intraerythrocytic glucose and sorbitol in diabetic subjects, statistically significant correlations have been demonstrated between sorbitol and filtration index, between plasma glucose, intracellular glucose level and glycosylated hemoglobin, suggesting a relationship between metabolic control and hemorheologic alterations in diabetes.

2,3-Diphosphoglycerate↗
PubMedDate not supplied

S-glutathionylation: from redox regulation of protein functions to human diseases.

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) play an integral role in the modulation of several physiological functions but can also be potentially destructive if produced in excessive amounts. Protein cysteinyl thiols appear especially sensitive to ROS/RNS attack. Experimental evidence started to accumulate recently, documenting that S-glutathionylation occurs in a number of physiologically relevant situations, where it can produce discrete modulatory effects on protein function. The increasing evidence of functional changes resulting from this modification, and the growing number of proteins shown to be S-glutathionylated both in vitro and in vivo support this contention, and confirm this as an attractive area of research. S-glutathionylated proteins are now actively investigated with reference to problems of biological interest and as possible biomarkers of human diseases associated with oxidative/nitrosative stress.

Disease↗
PubMedDate not supplied

Lithium preserves F-actin from the disarrangement induced by either DNase I or cytochalasin D.

Light scattering at 546 nm, which is mainly related to the presence of rodlike particles longer than 50 nm, showed that Li+ accelerates the formation of actin filaments. Intermolecular cross-linking with N,N'-1,4-phenylene-bismaleimide proved that the observed enhancement in the light-scattering intensity is caused by the increase in the concentration of actin oligomers, which gradually elongate to form longer filaments. DNase-I-related F-actin disassembly was reduced in the presence of lithium ions, as demonstrated by fluorimetric and viscometric experiments. Li(+)-F-actin showed an apparently similar behaviour when exposed to cytochalasin D. We confirm that Li+ acts on actin polymerization by stabilizing actin nuclei and polymers. The stabilization of cytoskeletal polymers really appears as one of the mechanisms by which lithium ions influence some of the cell activities.

Actins↗
PubMedDate not supplied

N-ethylmaleimide-modified actin filaments do not bundle in the presence of alpha-actinin.

We show that the modification of actin subdomain 1 by N-ethylmaleimide (NEM), which binds Cys-374 close to the C-terminus of the molecule, inhibits the alpha-actinin-induced bundling of actin filaments. This effect is not merely related to the block of Cys-374, since N-(1-pyrenyl)iodoacetamide (pyrene-IA) is unable to prevent bundling. Considering that NEM (but not pyrene-IA) influences actin assembly, we suggest that the inhibition of the actin-alpha-actinin interaction is due to the chemical modification of actin Cys-374 which, by inducing a marked spatial reorganization of actin monomers, is able to modify both the intra- and inter-molecular interactions of this protein. Finally, NEM-modified actin filaments form bundles in the presence of polyethylene glycol 6000 since, in this case, the side by side association of actin filaments does not depend on the accessibility of binding sites nor on the formation of chemical bonds.

Actin Cytoskeleton↗
PubMedDate not supplied

Hemodialysis with two sequential hemodialyzers.

BACKGROUND/AIMS: The principal aims of the new hemodialysis methods are: a short-time dialysis session, the increase of solute removal, the patient's well-being and, when possible, the reduction of global costs. Other researchers have experimented the simultaneous use of two hemodialyzers in hemodialysis. We tested a new technique which involves the use of two Cuprophan hemodialyzers in sequence (double filter system: DFS), each one connected separately to fresh dialysate. METHODS: We treated 15 large patients with DFS and compared the results with conventional hemodialysis (CHD). RESULTS: Our results showed a significant difference between CHD and DFS in the depuration values. After the first hemodialyzer, modification of pH and electrolytes occurred in the plasma composition. In the second hemodialyzer, urea depuration occurred without further significant changes in hydroelectrolytic and acid-basic plasma patterns. The Kt/V increased from 1.10 to 1.29 (18%). CONCLUSION: Our technique is conceived for the following goal: to increase the diffusion of solution without increasing costs and side effects.

Adult↗
PubMedDate not supplied

Transdermal electromotive multi-drug administration for Peyronie's disease: preliminary results.

The purpose of this study was to clarify the actual therapeutic potential of a new transdermal drug delivery system (electromotive drug administration; EMDA) for selected patients with Peyronie's disease. Forty patients with Peyronie's disease were treated by electromotive administration of the 3-drug association orgotein-dexamethasone-lidocaine in a double-blind, placebo-controlled, partial crossover study (study 1). Another 25 patients were treated by EMDA with a combination of verapamil-dexamethasone in an uncontrolled study (study 2). Treatment sessions lasted 20 minutes each and took place 3 times a week for 3 weeks with a current of 3 mA. Patients were assessed before treatment and at 1- and 3-month follow-up examinations. Assessments were based on sexual history, physical examination, and dynamic color Doppler ultrasonographic results. Adverse effects of EMDA were not reported. In study 1, the clinical results observed after treatment proved to be significantly better than those of the placebo. Penile pain disappeared in all patients in both studies. Penile lesion (nodule or plaque) either disappeared or significantly improved in 79% and 90% of patients treated by the 3- and 2-drug association, respectively. The improvement of penile deformity also was notable although it did not match the effect observed on penile nodules or plaque (62% and 88%, in studies 1 and 2, respectively). In both studies, more than 80% of patients reported a definite amelioration of penile rigidity, which paralleled the improvement of penile dynamic color Doppler ultrasonographic parameters. Overall, the combination of verapamil-dexamethasone achieved better clinical results than the 3-drug combination. Electromotive drug administration is a novel technique capable of safely achieving satisfactory results in selected patients with Peyronie's disease not only in terms of improvement of patient's symptoms but also due to the reduced need for penile surgery.

Administration, Cutaneous↗
PubMedDate not supplied

[PROCID: a project of the European Community for the study and prevention of muscular disorders in computer terminal operators].

This paper presents an EC funded concerted action aimed at studying the prevention of muscle disorders in the operation of computer input devices. About 40% the today's working population use computers in their daily work. This percentage is expected to increase dramatically in the coming years. At the same time health statistics indicate an increased incidence of work related musculoskeletal disorders among computer users. A deeper knowledge in this field may improve the health risk assessment approach, the design of computer input devices and the revision process of existing standards, norms and guidelines concerning computer work. Specific research objectives include: the development of intramuscular techniques suitable for mapping motor unit recruitment under operation of computer input devices; the evaluation of muscle fatigue and motor unit recruitment in dynamic tasks in normal subjects and in patients with pain syndromes; the experimental evaluation of stress induced muscular tension at the motor unit level, in operation of computer input devices; the formulation of recommendations for work with computer input devices.

Computer Terminals↗
PubMedDate not supplied

[Evaluation of the activity of the bladder detrusor muscle and analysis of bladder function in subjects with diabetes mellitus under insulin treatment].

The present report concerns investigations of detrusor muscle adrenergic innervations in patients affected by bladder neuropathy secondary to diabetes without obstructive disturbances. Detrusor contractile activity evoked by NE is markedly reduced which can probably be attributed to receptor deficit. Urodynamic evaluation demonstrated a prevalence of sensory peripheral neuropathy than a motor conduction abnormality. In vitro study demonstrated that motor conduction abnormality of detrusor contractile activity is present early without bladder disturbances. Therefore early urodynamic measurements are necessary to evaluate bladder dysfunction and neuropathy in diabetic patients.

Adult↗
PubMedDate not supplied

[Cellular metabolism of sodium and hypertension].

Essential hypertension develops from interactions between genetic and environmental components. Studies on cell membrane ions (in particular the sodium ion) transport in essential hypertension were originally carried out in order to better understand the roles these two components play in a less complex system than the overall organ system or the single organs involved in blood pressure regulation. The theory supporting this experimental approach is based on the observation that cell membrane function affects all the phenomena involved in blood pressure regulation. Receptor function, hormonal secretion, cell volume regulation, ion transport and ion composition of the cell are all regulated at the cell membrane level. However the problem of the relevance of cellular sodium metabolism in the pathogenesis of essential hypertension and of the interpretation of the many conflicting results has grown in complexity with the growing mass of data published in the literature. At least part of this complexity seems related to methodological problems but part is surely due to real differences among the various populations or subpopulations studied. This review analyzes the main sources of the discrepancies, the different ion transport systems and the end point of the overall transport system as well as the steady state intracellular cation concentration in both genetic animal models of essential hypertension and in man.

Animals↗