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Biomedical subjects

A Vianello

Publications and source records attributed to A Vianello.

At least 37 records · Page 2Linked to original sources
PubMed1996

Cardiac and respiratory involvement in advanced stage Duchenne muscular dystrophy.

This study aimed to describe myocardial involvement, respiratory impairment and pulmonary blood flow abnormalities in advanced-stage Duchenne muscular dystrophy (DMD). Twenty-one wheelchair-bound patients, aged from 10 to 24 yr, underwent electrocardiographic and echocardiographic examination, conventional spirometry, diurnal arterial blood gas analysis, and nocturnal polysomnography (SaO2 monitoring). Diagnosis was confirmed by neurological examination, dystrophin analysis at protein and DNA level. Patients were classified into two groups: group A normoxemic (14 cases) and group B with nocturnal hypoxemia (seven cases). Group A was further split into two subgroups, one without, and one with, left ventricular dilation (A1 = nine patients, end diastolic volume (EDV) = 51 ml m-2, ejection fraction (EF) = 56 per cent; A2 = five patients, EDV = 112 ml m-2, EF = 32 per cent; P < 0.05). Left ventricular regional wall motion abnormalities were found in 55, 40, and 43 per cent of groups A1, A2, and B patients respectively. Analysis of pulsed Doppler pulmonary data highlighted a significant reduction in corrected time to peak velocity in group B patients, when compared with control, A1, and A2 groups respectively. In group A, we observed a direct correlation between ejection fraction and corrected time-to-peak velocity. Two patterns of cardiac involvement may be recognized in advanced-stage DMD: left ventricular wall motion abnormalities and dilated cardiomyopathy. Doppler data which could suggest pulmonary hypertension may be observed in patients with dilated cardiomyopathy, and in patients with nocturnal hypoxemia. Therefore, in the management of advanced-stage DMD, a careful diagnosis of the heart-lung relationship should be performed, and both conventional treatment of heart failure and ventilatory therapy are necessary to improve the quality of life and survival in these patients.

Adolescent↗
PubMed1996

Zearalenone-induced uncoupling in plant mitochondria is sensitive to 6-ketocholestanol.

Zearalenone (F-2) is a mycotoxin which acts as a protonophoric uncoupler in plant mitochondria [Macri, F. and Vianello, A., (1990) J. Plant Physiol. 136, 754-757]. In the present paper, the mechanism of F-2-induced uncoupling in pea mitochondria was studied. The uncoupling by F-2 was partially reversed by 6-ketocholestanol (kCh) under conditions in which kCh completely reversed the FCCP-induced uncoupling and almost did not affect the palmitate-induced uncoupling. Recoupling effects of carboxyatractylate, ADP and cyclosporin A were small and could not essentially decrease the kCh-insensitive part of F-2-induced uncoupling. It is suggested that a protein, mediating kCh-sensitive uncoupling, is involved in the F-2 effect in plant mitochondria.

Atractyloside↗
PubMed1996

Importance of donor/recipient body weight ratio as a cause of kidney graft loss in the short to medium term.

The importance of the donor/recipient body weight ratio (DRBWR) as a cause of kidney graft loss was evaluated in 112 non-diabetic, ciclosporin-treated, first cadaver kidney transplant recipients. According to the DRBWR, the patients were divided into three groups: 'low' (< or = 0.80), 'medium' (0.81-1.20), and 'high' (> 1.20). The three groups did not differ in patient or graft survival, and the DRBWR was not a predictor of graft failure at multivariate analysis (Cox models), even after only patients with graft survivals > 1 year were considered. The three groups did not differ in glomerular filtration rate (GFR) and proteinuria 6-60 months after renal transplantation. When the 55 patients with a follow-up period > 4 years were considered, no differences between groups were found in GFR or GFR evolution over time. Hypertension was significantly less frequent in group 'high' (Mantel-Cox p = 0.04), but very likely as a consequence of uneven recipient gender (an independent predictor of hypertension at multivariate analysis) distribution between groups, the significance being lost when survival curves were rebuilt by stratifying for recipient gender. DRBWR never resulted as a significant predictor of GFR at multivariate analysis when GFR values 6-60 months after transplantation were analyzed. We conclude that the DRBWR has no major effects on kidney graft function and survival in the short to medium term.

Adolescent↗
PubMed1996

Influence of length of time on dialysis before grafting on kidney transplant results.

The outcome of kidney transplantation was evaluated in 246 nondiabetic, CsA-treated recipients of primary cadaver transplant, divided into 4 groups according to length of time on dialysis: group < or = 2, 0-24 months; group 2-5, 25-60 months; group 5-15, 61-180 months; group > 15, over 180 months. The 4 groups did not differ in graft survival, proteinuria (g/die), or estimated GFR values at 1, 2, 3, 4, and 5 years after grafting. They did not differ in the frequency of cataract, hip osteonecrosis, tumors, or posttransplant diabetes mellitus at 3 years after grafting. Ocular hypertone (p < 0.02), tendon ruptures (p < 0.001), arterial occlusive disease of lower limbs (p < 0.01), cholelithiasis (p < 0.05), and chronic hepatitis--which occurred only in anti-HCV and/or HBs Ag-positive patients--(p < 0.001), were more frequent in group > 15, and in all these cases but ocular hypertone a linear trend of increasing frequencies with increasing dialytic age was statistically significant. Group 5-15 had the lowest patient survival (p < 0.02). Moreover, a progressive decline of patient survival with increasing dialytic age was noted in groups < or = 2, 2-5, and 5-15. Unexpectedly, group > 15 had remarkably good survival, and this finding denies the hypothesis of a purely linear decline of patient survival after transplantation with increasing dialytic age.

Adolescent↗
PubMed1995

Effect of cyclosporin A on energy coupling in pea stem mitochondria.

Effect of cyclosporin A on energy coupling in pea stem mitochondria is studied. It is found that incubation of mitochondria with 100 nM FCCP and/or CAtr, oligomycin, CaCl2, palmitate and ADP results, after some lag phase, in a collapse of delta psi generated by succinate oxidation in the presence of rotenone. Cyclosporin A (0.2-0.8 nmol/mg mitochondrial protein) markedly increases the lag phase. The cyclosporin A effect requires dithioerythritol to be added to the isolated medium. Metabisulphite fails to substitute for dithioerythritol. The relationships between these effects and cyclosporin A-sensitive mitochondrial permeability transition in animal mitochondria are discussed.

Animals↗
PubMed1995

Effect of 6-ketocholestanol on FCCP- and DNP-induced uncoupling in plant mitochondria.

Effect of 6-ketocholestanol on FCCP-induced and DNP-induced uncoupling in beef liver and pea stem mitochondria was studied, under experimental conditions at which this steroid abolished the effect of low concentrations of FCCP and other most potent uncouplers in rat mitochondria [Starkov et al. (1994) FEBS Lett., 355, 305-308]. It is shown that, in both types of mitochondria, 6-ketocholestanol prevents or reverses the uncoupling induced by low concentrations of FCCP, but not that caused by high concentrations of FCCP or by any concentration of DNP. Progesterone and male sex hormones, showing recoupling capability in animal mitochondria, appear to be ineffective in the plant system. Cholesterol does not recouple in both animal and plant mitochondria. Plant steroids, such as beta-sitosterol and stigmasterol, are also without effect.

2,4-Dinitrophenol↗
PubMed1995

Lipoxygenase activity on the plasmalemma of sunflower protoplasts and its modulation.

A lipoxygenase (EC 1.13.11.12) activity on the plasmalemma of sunflower (Helianthus annuus L.) protoplasts and its possible modulation by regulatory molecules were investigated. The activity was followed as both linolenic acid-dependent conjugated diene formation and oxygen uptake. Protoplasts exhibited a lipoxygenase activity inhibited by propyl gallate, salicylhydroxamic acid and butylated hydroxytoluene, and stimulated by the addition of CaCl2, H2O2 and ATP. The stimulation by CaCl2 and H2O2 was evident up to 1.5 mM and 5 nM, respectively. Higher concentrations of H2O2 caused a lower extent of stimulation and then became inhibitory. The stimulatory effect of CaCl2 was prevented by chelators (EGTA or EDTA), a Ca2+ channel blocker (gadolinium oxide) or a Ca2+ ionophore (A23187). Negligible lipoxygenase was released from protoplasts after 6 h incubation in 3.6 mM MES-Tris (pH 5.6), 0.5 M glycine betaine and 1 mM CaCl2, whereas mechanical disruption of cell integrity, liberating soluble lipoxygenase, strongly increased such an activity. However, microsomal membranes obtained from hypocotyls still retained a part of this activity which was also recovered in a highly purified plasma membrane preparation.

Cell Membrane↗
PubMed1995

Isolation of the catalytic subunit of a membrane-bound H(+)-pyrophosphatase from pea stem mitochondria.

The catalytic subunit of a membrane-bound pyrophosphatase was purified by electroendosmotic preparative electrophoresis from etiolated pea stem mitochondria. The enzyme was identified as a single peak relatively pure, because only a very limited number of polypeptides were detectable by SDS/PAGE of the active fractions. The pyrophosphatase was associated to a band with a molecular mass of 35 kDa, showing a specific activity of 0.7 mumol Pi . mg-1 protein . min-1 (37 degrees C, pH 8.0) and an apparent Km value of 200 microM. The hydrolytic activity required Mg2+, was inhibited by imidodiphosphate (HNO6P2Na4), Ca2+, F- and was stimulated by phospholipids. Cardiolipin, phophatidylcholine and phosphatidylethanolamine had the maximal activating effect. The isolated protein is very similar to the catalytic subunit of pyrophosphatases isolated from rat liver (beta-subunit) and Saccharomyces cerevisiae mitochondria.

Mitochondria↗
PubMed1995

Locomotion patterns in cerebral palsy syndromes.

Locomotion patterns were studied in 160 children with cerebral palsy. Ten patterns were distinguished, which were typical of the type of impairment: (1) crawling--mildly impaired children who will achieve independent walking; (2) creeping and crawling--diplegic children with moderate motor impairment; (3) creeping, never leading to independent walking--children with severe diplegia or tetraplegia; (4) bottom shuffling--children with hemiplegia and ataxia and minimal or mild motor impairment; (5) bunny-hopping--dyskinetic children with marked motor impairment but generally not mentally retarded; (6) rolling--severely diplegic and dyskinetic children; (7) other forms of locomotion, such as bridging or grub-type creeping, rare and typical of children with ataxic elements; (8) just walk--children with hemiplegia, diplegia, ataxic diplegia or ataxia, generally in cases of mild motor impairment but mental retardation; (9) just walk with aids--children with severe diplegia; and (10) no mobility. The locomotion pattern, age at onset and even manner of execution all influenced prognosis for walking. Severe deformity affected the choice of locomotion pattern. Though physiotherapy probably would not greatly influence the adoption of a particular locomotion pattern, early intervention might help prevent deformities.

Adolescent↗
PubMed1994

Lipoxygenase activity associated to isolated soybean plasma membranes.

Highly purified soybean (Glycine max L. Merr.) plasma membranes exhibit a lipoxygenase activity with a pH optimum in the acidic (5.5-6.0) range and with a Km value of 200 microM for both linolenic and linoleic acids. This activity is inhibited by nordihydroguaiaretic acid (NDGA), salicylhydroxamic acid (SHAM) and propyl gallate, stimulated by CaCl2 up to 0.25 mM, H2O2 (5 to 10 nM range) and by some nucleotide triphosphates (125 to 1000 nM range) in the following order ATP > GTP = UTP > CTP. The enzyme is not released by treatment of the membranes with 0.05% Brij 58 and its activity is approx. 65% inhibited by the impermeant p-chloromercuryphenyl-sulfonate only in 0.01% Triton X-100-treated membrane vesicles. These results indicate that soybean cells have an acid lipoxygenase, associated to the plasmalemma, with the catalytic site on the cytoplasmic surface. It may be distinguished from the soluble counterpart, because the latter is not stimulated by nucleotide triphosphates. The plasma membrane vesicles also show a lipoxygenase, active in the alkaline (9.0-9.5) range, inhibited by NDGA, SHAM and propyl gallate, stimulated by H2O2, but with a lower Km value (60 microM) and less sensitive to calcium stimulation than the acidic one. The possible involvement of acid lipoxygenase in senescence and in the response of plant cells to wounding and pathogen infection is discussed.

Cell Membrane↗
PubMed1994

ATP/ADP antiporter is involved in uncoupling of plant mitochondria induced by low concentrations of palmitate.

Carboxyatractyloside partially restored the transmembrane electrical potential difference (delta psi) dissipated by low concentrations of palmitate in pea stem mitochondria. This effect was more marked when mitochondria from sunflower were assayed. It is suggested that the ATP/ADP translocator is involved in the free fatty acid-induced uncoupling of oxidative phosphorylation in plant mitochondria, only when its level is sufficiently high and the concentration of the fatty acid is low to collapse only partially the delta psi.

Atractyloside↗
PubMed1994

ATP/ADP antiporter is involved in uncoupling of plant mitochondria induced by low concentrations of palmitate.

Carboxyatractyloside partially restored the transmembrane electrical potential difference (delta psi) dissipated by low concentrations of palmitate in pea stem mitochondria. This effect was more marked when mitochondria from sunflower were assayed. It is suggested that the ATP/ADP translocator is involved in the free fatty acid-induced uncoupling of oxidative phosphorylation in plant mitochondria, only when its level is sufficiently high and the concentration of the fatty acid is low to collapse only partially delta psi.

Atractyloside↗
PubMed1994

Comparison of fast peritoneal equilibration tests with 1.36 and 3.86% dialysis solutions.

At present dialysis solutions with different glucose concentrations are used for the peritoneal equilibration test (PET) and Fast-PET in peritoneal dialysis (PD). We compared the results of two Fast-PETs, using 1.36 and 3.86% solutions sequentially in 30 patients on PD treatment, to obtain information on peritoneal transport (D/P-4 h) and ultrafiltration rates. Creatinine, phosphorus and urea D/P-4 h in the two Fast-PETs were not statistically different, unlike those for potassium, beta 2-microglobulin and glucose. The creatinine and phosphorus D/P-4 h values in particular proved to be uninfluenced by the different dialysis solutions. The lack of correlation between the two Fast-PET ultrafiltration values confirmed the difficulty in interpreting this parameter, above all in the case of non-homologous Fast-PETs. We obtained useful indications for comparing different Fast-PET results, but were unable to reach a decisive conclusion regarding the best of the two dialysis solutions for this test.

Aged↗
PubMed1994

Long-term nasal intermittent positive pressure ventilation in advanced Duchenne's muscular dystrophy.

The aim of our study was to evaluate the long-term effect of nasal ventilation in patients with advanced Duchenne's muscular dystrophy (DMD). To this end, we compared the clinical and pulmonary function course of five subjects affected with chronic ventilatory failure due to DMD and treated with nasal intermittent positive pressure ventilation (NIPPV) with that of an unventilated comparison group; the latter consisted of another five patients with DMD, with a similar degree of clinical and respiratory functional impairment, who refused long-term mechanical ventilation. The duration of the follow-up was 24 months. At the conclusion of the trial, all patients treated with NIPPV were still alive; in contrast, four of five patients who underwent simple conservative treatment had already died (mean survival, 9.7 +/- 5.8 months). After 6 months of follow-up, mean loss of FVC and maximal voluntary ventilation was considerably higher in nonventilated subjects (respectively: -0.23 L vs +0.03 L and -5 L/min vs -1.5 L/min). These are the first comparative results confirming that long-term NIPPV helps to stabilize pulmonary function and to prolong the expectancy of life of patients with DMD.

Adolescent↗
PubMed1994

Effect of carboxyatractylate on transmembrane electrical potential of plant mitochondria in different metabolic states.

The effects of carboxyatractylate (CAtr) on delta psi in sunflower hypocotyl and pea stem mitochondria were compared. In sunflower mitochondria, (1) CAtr at higher concentration increased delta psi in the presence of palmitate and delta psi in metabolic state 3; (2) ]1 microM CAtr did not prevent delta psi decrease, induced by ADP addition (in contrast to pea mitochondria); (3) The ATP-generated delta psi was small and was insensitive to 40 microM CAtr. Under the same conditions, in pea mitochondria generation of delta psi by ATP was inhibited by 1 microM CAtr.

Adenosine Diphosphate↗
PubMed1993

The role of hypertension as a damaging factor for kidney grafts under cyclosporine therapy.

The relative importance of glomerular filtration rate (GFR) and hypertension (permanent need for antihypertensive drugs) for the prognosis of kidney grafts was studied in 135 cyclosporine-treated primary cadaver kidney transplant recipients whose grafts lasted more than 1 year. The start point of 1 year after transplantation was chosen because hypertension developed within the first year in all our hypertensive patients. Graft prognosis in hypertensive patients was not significantly worse than that of normotensive patients; moreover at multivariate analysis, age at transplantation and GFR at 1 year (P = 0.014), but not hypertension, were significant prognostic factors for the graft. At logistic regression, GFR was a significant variable for hypertension (P = 0.009), but hypertension was not a significant variable for renal failure at 1 year (GFR < or = 0.83 mL/sec [50 mL n]; P, NS). Accordingly, hypertension per se resulted much more as a consequence of reduced renal function than as a direct cause of graft damage. However, when hypertensive patients were divided into controlled and uncontrolled, uncontrolled hypertensive patients had the worst prognosis (P = 0.03), and blood pressure control proved a strong prognostic factor for the graft, even after GFR was considered (P = value of the model considering blood pressure control, GFR, and age at transplantation: 0.007). Our data suggest that, apart from being an expression of reduced renal function, hypertension is also a direct kidney graft damaging agent, a role that can be controlled by strict reduction of blood pressure levels.

Adult↗