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Biomedical subjects

G Del Rosso

Publications and source records attributed to G Del Rosso.

At least 19 recordsLinked to original sources
PubMed1999

Endoscopy as a tool for diagnosing and treating gastrointestinal angiodysplasia in haemodialysis patients.

Gastroenteric angiodysplasia is an important cause of haemorrhage in chronic renal failure patients. This paper reports on 2 patients on maintenance haemodialysis with upper gastrointestinal bleeding due to different manifestations of angiodysplasic lesions (sudden appearance of haematemesis and melaena in one case, progressive anaemia with apparent resistance to erythropoietin in the other case). Exploratory endoscope examination of the first digestive tract showed in both cases the presence of bleeding angiodysplasic lesions. Both patients were there and then submitted to surgical endoscopy, during which the bleeding angiodysplasic lesion was sclerosed with physiological salt solution plus adrenaline 1/10000 and 1% polydocanol. In one patient, bleeding occurred again ten days later, making renewed surgical endoscopy necessary. In the course of this an elastic ligature was made to the superangular angiodysplasia. A year later in both cases there were no direct or indirect signs of further bleeding; an endoscopic check-up showed the treated lesions to be sclerosed. Endoscopy offers the unique possibility of being used for both diagnostic and therapeutic purposes in a single session. In expert hands, endoscope therapy is effective and markedly reduces the risk of side effects.

Aged↗
PubMed1996

Vanadate as factor of cardiovascular regulation by interactions with the catecholamine and nitric oxide systems.

The effects of 1 microgram/mL of vanadium, given for 12 mo as sodium metavanadate in drinking water, on cardiovascular and biochemical indices of male rabbits were investigated. At the end of the exposure period, vanadium was more accumulated in bones and kidneys than in spleen and liver; the cardiac ventricles and the aorta contained similar amounts of this element. Blood pressure and heart rate were unchanged in the vanadate-exposed animals since the observed decrease of both cardiac inotropism and stroke volume was counteracted by an increase of peripheral vascular resistance, with reduction of arterial blood flow. The arterial levels of sodium, potassium and aldosterone were unmodified by vanadate which, however, strongly raised those of noradrenaline, adrenaline, L-DOPA, and dopamine. Vanadate caused a marked increase of the activity of monoamine oxidase in renal tubules and liver (probably in relation to the increased plasma catecholamine levels) and a reduction of that of glucose-6-phosphate dehydrogenase in the kidney. There was also evidence that vanadium reduces synthesis and/or release of nitric oxide, the endothelium-derived vasodilating factor, likely through a reduced formation from bradykinin. It was concluded that vanadium may represent an environmental factor of altered cardiovascular homeostasis.

Animals↗
PubMed1995

The value of dipyridamole echocardiography in risk stratification before vascular surgery. A multicenter study. The EPIC (Echo Persantine International Study) Group--Subproject: Risk Stratification Before Major Vascular Surgery.

PURPOSE: Patients undergoing major vascular surgery are at relatively high risk of cardiac events, and pharmacological stress echocardiography is increasingly used for peri-operative risk stratification. PATIENTS AND METHODS: One hundred and twenty-one patients undergoing vascular surgery (age 65 +/- 7 years) were studied by dipyridamole echocardiography testing in six different centres. Of the total 136 patients, 15 were subsequently excluded because surgery was either cancelled (n = 8) or postponed pending cardiac revascularization (n = 7) because of the presence of a 'high-risk' stress echo response (identified 'a priori' as a positive dipyridamole echocardiography testing with a dipyridamole-time < 5 min and/or a peak wall motion score index > 2, upon scoring each segment from 1 = normal to 4 = dyskinetic in an 11-segment model). RESULTS: No major complications occurred during dipyridamole echocardiography testing. Technically adequate images were obtained in all patients; however, in one patient only the low dipyridamole dose (56 mg.kg-1 over 4 min) was given to limit side effects. Of the 121 patients undergoing surgery 28 (23%) had a positive test. Peri-operative events occurred in nine patients (8%): two deaths, two myocardial infarctions, five cases of unstable angina. Sensitivity and specificity of dipyridamole echocardiography testing for predicting cardiac events were 78% and 81%, respectively, with a positive predictive value of 25% and a negative predictive value of 98%. Dipyridamole echocardiography testing effectively singled out patients with, from those without, events, but neither clinical parameters, such as Detsky score, nor baseline echo parameters, such as resting wall motion score index or ejection fraction were able to distinguish between such patients. CONCLUSION: In conclusion, dipyridamole echocardiography testing is safe and well tolerated in patients undergoing major vascular surgery, and provides an effective pre-operative screening test for risk stratification of these patients mainly due to the extremely high negative predictive value. Stress echocardiography is a better discriminator than clinical and rest echocardiographic variables.

Aged↗
PubMed1994

Renal toxicity and arterial hypertension in rats chronically exposed to vanadate.

The effects of 1, 10, or 40 micrograms/ml of vanadium, given for six or seven months as sodium metavanadate in drinking water on cardiovascular and biochemical variables and the electrolyte metabolism of male Sprague-Dawley rats were investigated. At the end of the exposure period, all animals exposed to vanadate had increased systolic and diastolic blood pressure. This effect was not dose dependent and heart rate and cardiac inotropism were not affected. The role of defective renal function and electrolyte metabolism in such effects was supported, in the rats exposed to 10 and 40 ppm of vanadium, by the following changes: (a) decreased Na, + K(+)-ATPase activity in the distal tubules of nephrons; (b) increased urinary excretion of potassium; (c) increase in plasma renin activity and urinary kallikrein, kininase I, and kininase II activities; (d) increased plasma aldosterone (only in the rats treated with 10 ppm of vanadium). The alterations in the rats exposed to 1 ppm of vanadium were: (a) reduced urinary calcium excretion; (b) reduced urinary kallikrein activity; (c) reduced plasma aldosterone. These results suggest that blood hypertension in rats exposed to vanadate depends on specific mechanisms of renal toxicity related to the levels of exposure.

Animals↗
PubMed1992

Renal mechanisms in the cardiovascular effects of chronic exposure to inorganic mercury in rats.

Male weanling Wistar rats received 200 micrograms/ml of mercury (Hg), as HgCl2, in drinking water for 180 days. At the end of the treatment, systemic arterial blood pressure was augmented, cardiac inotropism was reduced, and heart rate was unchanged. Light and electron microscopical studies of the kidney showed a mesangial proliferative glomerulonephritis in about 80% of the glomeruli. Tubular cells showed reduction of the acid phosphatase activity, which was related to functional abnormalities of the lysosomes. In the 24 hour urine samples of the Hg exposed rats, there was slight reduction of kallikrein activity, but evident proteinuria was not present in all samples. Plasma renin activity was reduced, that of angiotensin I-converting enzyme was augmented, and plasma aldosterone concentrations were unchanged. Mercury was accumulated mostly in the kidney of the Hg treated animals; and the content of Hg in the heart was higher than in the brain. These data show that chronic exposure to Hg acts on the kidney with complex mechanisms of toxicity; these contribute to modify systemic haemodynamics.

Animals↗
PubMed1990

Computerised non-invasive monitoring of cardiovascular stress in haemodialysis patients.

Haemodynamic instability is one of the most frequent problems occurring during dialysis treatment. Ten clinically stable patients (8 M and 2 F) undergoing chronic maintenance haemodialysis for at least 6 months were investigated. Two groups of five patients each, were selected on the basis of presence (IG) or absence (SG) of cardiovascular instability during dialysis. The cardiovascular function was assessed by computerised electrical bioimpedance performed during dialysis setting and by echocardiography immediately pre- and post-dialysis. In SG dialysis treatment did not change cardiac index (CI), stroke index (SI) and systemic vascular resistances index (SVRI). However CI, SI and SVRI, tended to decrease in IG patients; the reduction in CI was primarily due to a decrease in SI. Ejection velocity index increased significantly in SG but not in IG. Evaluation of cardiac function by Döppler echocardiography revealed a significant increment in fractional shortening, mean velocity of circumferential fiber shortening and Suga' index in SG with dialysis but not in IG. Stress index decreased significantly in both groups. Hormonal and biochemical parameters were not significantly different before and after dialysis in both groups. In IG the decrease in mean blood pressure, due to a reduction of SI, recognises in the inadequate response of myocardial contractility to volume subtraction, the genesis of its drop. Finally, impedance cardiography in uraemic patients helps to identify the factors that contribute to the impairment of cardiac performance and that should be studied before selecting new and advanced dialysis programmes.

Adult↗
PubMed1988

Electrophysiological aspects of nervous conduction in uremia.

Some neurophysiological techniques have been employed in clinical nephrology to record abnormalities of nervous conduction in central and peripheral pathways. The electrical monitoring on the peripheral and central nervous systems has allowed the detection of uremic neural injury, the diagnosis of specific electrophysiological abnormalities, the evaluation of various treatments employed and the identification of those abnormalities that uremia can induce. A group of 156 subjects subdivided into four groups were examined: 100 healthy subjects (64 M, 36 F); 56 patients (21 glomerulonephritis, 14 pyelonephritis, 5 nephrolithiasis, 5 polycystic kidney, 4 nephroangiosclerosis, 7 undetermined) with chronic renal failure treated with a conventional low nitrogen diet (CLND, 0.6 g/kg b.w./d. of proteins), 8 of whom passed from CLND to a very low nitrogen diet supplemented with alpha-keto-analogues; a group of 22 of these 56 underwent a regular dialysis treatment for 12 to 15 hours/weekly for 40.5 +/- 10.2 months. Three patients of the CLND group and 13 patients underwent renal transplantation after a variable period of RDT. In the uremic patients we found different populations of motor unit potentials; a decreased MNCV was found in 35% of the CLND patients, RDT patients had slowed MNCV in 42%. The SNCV was compromised more frequently than the MNCV. An increased duration of evoked potentials was sometimes observed in CLND and RDT patients inducing us to consider this a hallmark of uremic syndrome. The alpha-keto-analogues and HD/HP treated patients showed an improvement in several features.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Evoked potentials in uremia: basal and follow-up data.

Various EPs have been employed to disclose even early-stage central and peripheral nervous system damage in uremia. This approach also gives the possibility to follow up alterations of many sensory functions during the sequential stages of uremia. Fifty-three subjects (35 male and 18 female, mean age 42.20 +/- 5.50 yrs, conventionally low nitrogen diet treated, on dialysis or transplanted) were followed-up by recording the EPs every year for seven years. The P100 wave latency and amplitude of VEPs were recorded and found abnormal in about 70% of the examined visual systems. The auditory EPs were abnormal in 53% of the cases for the peak latencies, interpeak times and peak ratios. The somatosensory EPs showed in 75% of the cases an altered latency and morphology of the waves registered in the lumbar, cervical and cranial loci. There is evidence suggesting that evoked cerebral biorhythms may provide sensitive and objective indexes of cerebral function in uremia. The persistence of abnormalities disclosed by EPs follow-up confirm the reliability of this technique in evaluating neuro-pathologic uremic situations and in supplying optimal uremia therapies.

Adult↗