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Biomedical subjects

R Rossi

Publications and source records attributed to R Rossi.

At least 253 records · Page 14Linked to original sources
PubMed1995

Photoinduction of micronuclei by 4,4',6-trimethylangelicin and 8-methoxypsoralen in different experimental models.

The frequencies of micronuclei induced by treatment with 4,4',6-trimethylangelicin (TMA) and 8-methoxypsoralen (8-MOP) have been compared in the following experimental models: (1) peripheral normochromatic erythrocytes (NCE) during 10 days after single p.o. administration of TMA or 8-MOP in male and female mice; (2) peripheral NCE during photocarcinogenesis by TMA or 8-MOP topically administered to female mice; (3) primary cultures of human skin fibroblasts treated with TMA or 8-MOP. The frequency of micronuclei in peripheral NCE of mice (both sexes) was significantly enhanced after p.o. administration of TMA or 8-MOP. This latter was more active than TMA in inducing chromosomal damage. No increased frequencies of micronuclei in peripheral NCE were detected in mice subjected to TMA or 8-MOP photocarcinogenic treatment, even when malignancies developed. In human fibroblast cultures, at equimolar concentrations, the induction of lethal effects by TMA in the presence of 365-nm radiation was higher than that exerted by 8-MOP. At equal survival, however, TMA showed practically the same activity as 8-MOP in the induction of micronuclei. Our findings provide evidence of genotoxicity by TMA administered p.o. without irradiation and give further information about photogenotoxicity of these substances.

Animals↗
PubMed1995

Hyperpolarization of the cell membrane of mouse hepatocytes by fatty acid oxidation.

The effect of palmitate and metabolizable and nonmetabolizable monosacharides (D-glucose, D-fructose and 2-deoxy-D-glucose = 2-DG) on the membrane potential (Vm) of mouse hepatocytes was investigated employing a superfused mouse liver slice technique. Palmitate hyperpolarized the liver cell membrane in a concentration dependent manner whereas the monosaccharides tested did not. When mice were fed a fat-rich diet, the hyperpolarisation was greater in comparison to mice fed a low fat diet. The hyperpolarization was reversed by ouabain, an inhibitor of the Na+/K(+)-ATPase, by the K(+)-channel blockers tetra-ethyl-ammonium (TEA) and cetiedil and by three inhibitors of fatty acid oxidation (2-bromopalmitate, 2-bromooctanoate and 4-pentenoate). The results suggest that hyperpolarization of the liver cell membrane is due to fatty acid oxidation and that both activation of Na+/K(+)-ATPase and opening of K(+)-channels are involved. The implications of these findings with regard to control of food intake by fatty acid oxidation are discussed. The results are consistent with a role of the hepatic membrane potential in control of food intake by fatty acid oxidation.

Animals↗
PubMed1995

Cardiovascular and organ responses and adaptation responses to hypogravity in an experimental animal model.

The head-down suspension (i.e. antiorthostatic hypokinesia) rat is used to simulate weightlessness. However, little is known about cardiovascular and organ adaptation responses which, over a long time, can become pathologically significant. The purpose of this study was therefore to evaluate regional changes in the hematology parameters. Endotheline-1 (ET-1) concentration and urinary excretion of N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30) (NAG) in an experimental antiorthostatic rat model. The data indicate significant variations in the plasma ET-1 level in time, in the superior and inferior cava vessel blood of animals maintained for 10 days in hypogravity with respect to controls. These changes do not seem to be due to hemoconcentration. The increase in urinary NAG was observed during the first 24h of experiment, indicating renal stress, probably due to adverse blood flow variations within the organ. We conclude that the plasma ET-1 level changes could be responsible, overall for the blood flow variations in the kidney and renal stress could be the consequence of extended antiorthostatic hypokinesia. The ET-1 behaviour and urinary NAG excretion in rats exposed to antiorthostatic hypokinetic hydynamia offer possibilities for understanding if these changes might be reversible or when they become pathological. This could give some relevant information about the effects of prolonged hypogravity during the space voyage.

Acetylglucosaminidase↗
PubMed1995

Technical aspects and late functional results of gastroepiploic bypass grafting (400 cases).

From January 1990 to February 1994, 400 patients (mean age 59 +/- 9 years) underwent myocardial revascularization using the right gastroepiploic artery (GEA) to bypass the right coronary artery trunk or branches. They represented 40% of all patients undergoing isolated coronary surgery during the same period, from 19% in 1990 to 54% in 1994. Left ventricular function was normal in 32% of patients, moderately impaired in 62% and severely impaired in 6%. The GEA was used alone in six patients, associated with one internal mammary artery (IMA) in 111 patients (two arterial grafts, 2.2 +/- 0.4 anastomoses) and with both IMAs in 283 patients (three arterial grafts, 3.4 +/- 0.6 anastomoses); no vein graft was used. The rate of complete myocardial revascularization was 79%. Early mortality was 1.7% and influenced by left ventricular ejection fraction (P < 0.05). Complications occurred in 37 patients: myocardial infarction 4%, intra-aortic balloon pump 0.5%, reoperation for bleeding 0.5%, mediastinitis 0.25%. Early (15th postoperative day) angiographic control of the GEA graft was performed in 104 patients operated from January 1990 to December 1991 and the patency rate was 92%; anomalies of GEA were three occlusions, five stenoses, three competitive flow, no string or slender sign. Early functional results (3 +/- 1 months postoperatively) were studied in 192 patients during exercise test with medical treatment: 99% were symptom-free and 14% had electrocardiographic (ECG) ischemic modification significantly correlated with incomplete revascularization (P < 0.01). The 2- and 4-year actuarial survival rate was 96.7 +/- 1.9%. The rate of late cardiac events was 2% patient/year; Angioplasty for GEA graft failure was required in four patients. A 2-year postoperative functional assessment without medical treatment was performed during exercise test in 66 patients who had received three arterial grafts: 98% were symptom-free and 26% had ECG ischemic modification significantly correlated with incomplete revascularization (P < 0.01); during the same procedure, thallium myocardial scintigraphy was obtained in 50 patients: 18 patients (36%) had asymptomatic ischemic defects on exercise significantly correlated with incomplete revascularization and ECG ischemic changes (P < 0.01). However, posterior thallium defects demonstrated limited GEA flow at the maximum level of exercise in at least 8% of patients. Myocardial revascularization using the GEA can be achieved with minimal operative risk and offers satisfactory functional results and midterm survival rate.

Adult↗
PubMed1995

Extreme hypotrophy of the lower body pole, extensive hypoplasia of the spinal column and multiple anomalies of abdominal organs: a maximal variant of the caudal regression sequence?

A newborn with extreme hypotrophy of the lower body pole and aplasia of the lower spinal column is reported. Additional anomalies of internal organs included absence of one kidney and ureter, a diaphragmatic hernia, and anal atresia. Part of the organs located in the lower body pole were necrotic. There were no excretory apertures, and external genitalia were absent. Chromosomal analysis revealed a 46,XY karyotype. The multiple anomalies seen in this newborn may be interpreted as a maximal variant of the caudal regression sequence.

Abnormalities, Multiple↗
PubMed1995

Glutathione, glutathione utilizing enzymes and thioltransferase in platelets of insulin-dependent diabetic patients: relation with platelet aggregation and with microangiopatic complications.

Reduced glutathione (GSH) and activity of GSH related enzymes play a key role in defence against oxygen free radicals, whose production is, as known, raised in patients affected by diabetes mellitus, and at the same time they may contribute to the process of platelet aggregation. The purpose of this study was to evaluate GSH levels and activity of glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-Red), glutathione transferase (GSH-Tr), glucose-6-phosphate-dehydrogenase (G6PDH), and thioltransferase (TT) in platelets of insulin-dependent diabetic patients in fair metabolic control (mean glycated haemoglobin: 6.5%), as related to presence of retinopathy, neuropathy or nephropathy and to platelet aggregation by arachidonic acid (AA) in vitro. Mean effective dose (ED50) of AA was on average significantly lower in the group of insulin-dependent diabetic patients (0.41 +/- 0.02 mM (SEM), n = 46) as compared with that of control subjects strictly matched for age, sex and weight (0.77 +/- 0.02, n = 51; P = 0.0001). Mean platelet GSH as well as the activity of GSH related enzymes expressed as geometric mean (95% confidence intervals) were similar in diabetic patients and in controls, except for GSSG-Red whose activity was significantly higher in diabetic subjects (28.5 (14.4-57.5) mU 10(-9) platelets vs. 20.3 (8.7-56) mU 10(-9) platelets; P = 0.01). In the diabetic group TT was reduced when compared with healthy controls (3.8 (0.9-12.2) mU 10(-9) platelets vs. 6 (1.6-26.1) mU 10(-9) platelets; P = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Causes of death in patients with unipolar single chamber ventricular pacing: prevalence and circumstances in dependence on arrhythmias leading to pacemaker implantation.

Cardiac pacing improves the prognosis of patients with severe impulse formation and conduction disturbance, though sudden death can occur frequently in paced patients. In the present study, we analyzed the causes and the circumstances of 378 deaths in 2,243 paced patients followed over a 5-year period. Sudden cardiac death occurred in 71 of these 378 patients (18.7%), 56 patients died of stroke (15%), heart failure was the cause of death in 91 subjects (24%). We analyzed the causes of death in two groups with respect to the arrhythmia that had led to pacemaker implantation. The prevalence of cardiac sudden death was higher in patients with AV block than in patients with sick sinus syndrome, while stroke was more frequent in patients with sick sinus syndrome, particularly those with both fast and slow components. Atrial fibrillation is common in patients with sick sinus syndrome and is an important well-known risk factor for stroke. Death from heart failure was frequently reported in our population, but in our study group only a few patients had heart failure at the moment of pacemaker implantation. We conclude that sudden death is a common event in paced patients and the disturbance that led the patient to pacemaker implantation was also a factor in the cause of death.

Aged↗
PubMed1995

Human galanin reduces plasma norepinephrine levels in man.

The neuropeptide galanin (GAL) is widely distributed in the peripheral and central nervous systems, where it often coexists with catecholamines. To gain insight into the action of human GAL on sympathetic nervous system activity in man, we investigated the effects of a 60-min infusion of human (h) GAL (80 pmol/kg.min) or saline on peripheral norepinephrine (NE) and epinephrine concentrations, heart rate (HR), and systolic and diastolic blood pressure (BP) in the supine position as well as after assumption of the upright posture (UP) in eight healthy male volunteers. hGAL depressed supine plasma NE (0.84 +/- 0.06 vs. 0.33 +/- 0.02 nmol/L) and blunted the NE response to assumption of the UP (1.68 +/- 0.03 vs. 0.44 +/- 0.03 nmol/L), but caused a significant enhancement of the epinephrine response to assumption of the UP (0.22 +/- 0.02 vs. 0.65 +/- 0.06 nmol/L). hGAL significantly increased supine HR (70 +/- 2 vs. 99 +/- 4 beats/min) and potentiated the HR response to assumption of the UP (82 +/- 3 vs. 107 +/- 4 beats/min). hGAL did not alter supine systolic and diastolic BP, but caused a significant decrease in the systolic (121 +/- 3 vs. 98 +/- 2 mm Hg) and diastolic (74 +/- 2 vs. 62 +/- 2 mm Hg) BP responses to assumption of the UP. Our data show that hGAL decreases supine position- and UP-stimulated release of NE, suggesting an inhibitory modulation of hGAL on sympathetic outflow in man. The finding that hGAL induces an increase in HR, both in the supine position and after UP, and an inhibition of the systolic and diastolic BP response to UP provides further support for an involvement of hGAL in regulation of the cardiovascular and autonomic nervous systems in man.

Adult↗
PubMed1995

Percutaneous computed tomography-guided ethanol injection in aldosterone-producing adrenocortical adenoma.

The feasibility, safety and effectiveness of percutaneous computed tomography-guided ethanol injection (PEI-CT) was investigated in a patient affected by aldosterone-producing adenoma (APA). A 42-year-old male patient with typical features of hyperaldosteronism presented a solitary left adrenal adenoma measuring 2 cm, with a normal contralateral gland, evidenced by both CT scan and adrenal [75Se-19]-nor-cholesterol scintigraphy. After normalization of potassium plasma levels, 4 ml of sterile 95% ethanol with 0.5 ml of 80% iothalamate sodium was injected. The procedure was completed in about 30 min. No severe pain or local complication was noted. Five hours after PEI, a fourfold and a twofold increase in aldosterone and cortisol plasma levels were observed, respectively. After 11 days on a normal sodium and potassium diet, normal potassium plasma levels and reduced aldosterone plasma levels were present, with reappearance of an aldosterone postural response. Plasma renin activity and aldosterone plasma levels normalized 1 month later, with reappearance also of a plasma renin activity postural response and maintenance of normal potassium plasma levels even on a high sodium and normal potassium diet. The patient has remained hypertensive, although lower antihypertensive drug dosages have been employed. After 17 months, normal biochemical, hormonal and morphological findings were still present. Thus, we suggest PEI-CT as a further alternative approach to surgery in the management of carefully selected patients with APA.

Adrenal Cortex Neoplasms↗
PubMed1995

Effect of human galanin on the response of circulating catecholamines to hypoglycemia in man.

Human galanin (hGAL) is a neuropeptide with 30 amino acid residues that has been found in the peripheral and central nervous system, where it often co-exists with catecholamines. In order to clarify the possible role of hGAL in the regulation of sympathoadrenomedullary function, the effect of a 60-min infusion of hGAL (80 pmol.kg-1.min-1) on plasma epinephrine and norepinephrine responses to insulin-induced hypoglycemia in nine healthy subjects was investigated. Human GAL administration significantly reduced both the release of basal norepinephrine and the response to insulin-induced hypoglycemia, whereas it attenuated the epinephrine response by 26%, with the hGAL-induced decrease in epinephrine release failing to achieve statistical significance. Human GAL significantly increased the heart rate in resting conditions and clearly exaggerated the heart rate response to insulin-induced hypoglycemia, whereas it had no effect on the blood pressure. We conclude that GAL receptor stimulation exerts an inhibitory effect on basal and insulin-induced hypoglycemia-stimulated release of norepinephrine. These findings provide further evidence that GAL may modulate sympathetic nerve activity in man but that it does not play an important role in the regulation of adrenal medullary function.

Adrenal Medulla↗
PubMed1995

A scanning electron microscope study comparing the effectiveness of different types of sharpening stones and curets.

The effects of various types of sharpening stones on standard carbon steel Gracey type curets, and the influence of the sharpened curets on periodontally involved root surfaces, during in vitro scaling and root planing, was evaluated by means of scanning electron microscopy (SEM). Six different sharpening stones of varying texture, two of aluminum oxide, two India, and two Arkansas stones were assigned to sharpen six groups of 10 curets each. The curets were first examined under SEM and photographed and all exhibited edge irregularities. They were then sharpened with the different stones and again examined and photographed using SEM. The sharpness of each instrument was graded, related to the type of stone used, and the data compared statistically. A positive correlation was found between the texture of stone used and the surface sharpness it produced on the cutting edge of the instrument. The curets were then used to root plane the root surfaces on periodontally involved, extracted teeth. Replicas of the root surfaces were examined with SEM before and after removal of the smear layer with 10% EDTA. The planed and cleaned root surfaces revealed the effects of the sharpened instruments, with the relative surface roughness of the instrument being imparted to the tooth surface. The curets sharpened with finger grit stones produced smoother surfaces than those sharpened with the rough or coarse grit stone. It may be concluded that the sharpness of curets is related to the type of sharpening stone used and in turn to the smoothness of the planned root.

Aluminum Oxide↗
PubMed1995

Concentrating capacity in ifosfamide-induced severe renal dysfunction.

BACKGROUND: Diabetes insipidus renalis has only occasionally been reported in ifosfamide-induced renal Fanconi's syndrome, but in two studies on subclinical renal impairment, low morning urine osmolarity was found in high frequencies. This study was performed to assess the frequency of defective concentrating capacity in patients with ifosfamide-induced renal Fanconi's syndrome or severe impairment of proximal tubular function. PATIENTS AND METHODS: Seven patients with overt Fanconi's syndrome and 5 with a generalized but subclinical tubulopathy were examined. Beside proximal tubular solute reabsorption and estimation of glomerular filtration rate, urinary osmolarity was measured after overnight fast and DDAVP (1-D-amino-8-D-arginine vasopressin) testing. RESULTS: Five out of 7 patients with overt Fanconi's syndrome, but no patient with only subclinical tubular damage, had decreased osmolarities by at least one test. Increased sodium excretion was additionally found in 4 of these patients. CONCLUSION: Impaired renal concentrating capacity is a rare event in ifosfamide-induced renal dysfunction and confined to patients with overt Fanconi's syndrome. These patients should, however, undergo evaluation of concentrating capacity and renal sodium handling as decreased concentrating capacity and increased sodium excretion would render a patient at risk for dehydration episodes.

Adolescent↗
PubMed1995

"In vitro" and in animal model studies on a double virus-inactivated factor VIII concentrate.

To improve the safety of plasma derived factor VIII (FVIII) concentrate, we introduced a final super heat treatment (100 degrees C for 30 min) as additional virus inactivation step applied to a lyophilized, highly purified FVIII concentrate (100 IU/mg of proteins) already virus inactivated using the solvent/detergent (S/D) method during the manufacturing process. The efficiency of the super heat treatment was demonstrated in inactivating two non-lipid enveloped viruses (Hepatitis A virus and Poliovirus 1). The loss of FVIII procoagulant activity during the super heat treatment was of about 15%, estimated both by clotting and chromogenic assays. No substantial changes were observed in physical, biochemical and immunological characteristics of the heat treated FVIII concentrate in comparison with those of the FVIII before heat treatment.

Animals↗
PubMed1995

[Scintigraphic characterization of expansive lesions located in the adrenals. Comparison with magnetic resonance imaging].

In this study, 35 patients (11 men and 24 women, mean age 47 +/- 16 years) with unilateral adrenal masses underwent nor-cholesterol (nor-Chol) (n = 11), metaiodobenzylguanidine (MIBG) (n = 15) or nor-Chol and MIBG (n = 9) radionuclide studies. In all patients Magnetic Resonance (MR) adrenal imaging was also performed. In 19 (54%) patients, no laboratory abnormalities of adrenal function were observed. In the other 16 (46%) patients, adrenal hyperfunction was found. In 21 lesions, histology showed 10 pheochromocytomas (Pheos), 6 adenomas, 3 metastases, 1 cyst and 1 nodular focal liver hyperplasia. In the remaining 14 lesions, increased cortisol (n = 4) or aldosterone (n = 2) levels and/or intense nor-Chol uptake (n = 14) were considered suggestive of adenoma. Diagnostic accuracy of both nor-Chol and MIBG radionuclide studies in correctly identifying adenoma or Pheos was 100%. Conversely, qualitative MR signal intensity (SI) analysis on T2-weighted images did not allow to accurately distinguish lesions of different nature. In particular, 10 Pheos, 8 adenomas, 3 mestastasis and 1 cyst clearly showed on T2-weighted images higher SI than the liver; 5 adenomas had a slight higher SI; the remaining lesions (7 adenomas and 1 liver hyperplasia) exhibited low SI. In conclusion, adrenal scintigraphy using nor-Chol or MIBG allows to identify adenomas and Pheos, respectively. Conversely, qualitative MR SI analysis cannot differentiate different adrenal lesion (Pheos, adenoma, metastasis and cyst) and yields heterogeneous results in adenomas.

3-Iodobenzylguanidine↗
PubMed1994

The time-course of mixed disulfide formation between GSH and proteins in rat blood after oxidative stress with tert-butyl hydroperoxide.

Variations in time of GSH, GSSG and glutathione-protein mixed disulfides (GSSP) were studied in rat blood in vitro experiments of oxidative stress with tert-butyl hydroperoxide (t-BOOH, dose range 0.3-2 mM; time range 15 sec-60 min). The aim was to elucidate the potential for GSSG reduction of protein-bound SH groups (PSH). GSSP was estimated by two methods, indirectly from GSHt (GSH + 2 GSSG) variations and directly from precipitated and washed proteins. After treatment with t-BOOH, GSH and GSSG concentrations showed an immediate (15-30 sec) drop and a peak respectively and returned to control levels (time zero values) between 30 and 60 min. A t-BOOH dose-dependent minimum of GSHt and a corresponding GSSP maximum were obtained within 1-6 min and subsequently returned to control values. Basal GSH, GSSG and GSSP levels were similar in aged and fresh blood. In contrast, after treatment with 1 mM t-BOOH substantial differences in kinetic patterns were observed: for instance GSSP concentrations were higher in aged than in fresh blood with no return to the initial values. The pretreatment of aged blood with 10 mM glucose decreased GSSP formation and produced a reversible pattern similar to that observed in fresh blood. The role of glucose in regulating GSSP generation is discussed.

Animals↗