Search PubMed⌕ Search

Biomedical subjects

M Valente

Publications and source records attributed to M Valente.

At least 109 records · Page 6Linked to original sources
PubMed1994

Fat-tissue injection versus graft: experimental study in rabbits.

An experimental study of fat-tissue implants in the ears and frontal regions of rabbits was conducted, starting with blocks of tissue for surgical implantation or with multifragmented pieces for injection. The implants were observed from day 7 to month 12. Low integration levels were observed in all animals, except for 1 case that had 20% and 42% of integration, respectively, for the block grafts and for the injected multifragmented tissue.

Adipocytes↗
PubMed1994

Sudden death in the young. Is acute coronary thrombosis the major precipitating factor?

BACKGROUND: Atherosclerotic coronary artery disease, complicated by acute thrombosis, is the usual cause of sudden death in adults. This study addresses the pathology of coronary arteries in sudden death in the young (< or = 35 years old). METHODS AND RESULTS: Among 200 consecutive cases of sudden death in youth in the Veneto region of Italy, 37 (33 men and 4 women, age 18 to 35 years; mean, 29.4 years) showed obstructive atherosclerotic coronary artery disease in the absence of other cardiac pathological conditions and causes of death. No patient had previous angina pectoris or myocardial infarction. Cardiac arrest occurred at rest in 30 subjects and was related to effort in 7. A histological study was carried out on the obstructive coronary plaques. Degree of lumen stenosis and extension of lipid core and intimal fibrocellular hyperplasia facing the lumen were calculated morphometrically. Immunohistochemistry and electron microscopy were used to further characterize the plaque cell population. Single-vessel disease was found in 33 patients and triple-vessel disease in 4, with an overall total of 45 obstructive plaques, 34 of which were located in the proximal left anterior descending coronary artery. At histological study, only 10 plaques from 10 patients showed acute thrombosis (occlusive in 5 and subocclusive in 5); the remaining 35 were uncomplicated. Thirty-one plaques were fibrous in nature, while the other 14 were atheromatous. Compared with the atheromatous lesions, the fibrous plaques were rarely complicated by thrombosis (3% versus 64%; P < .001) and distinctly exhibited a fairly well-preserved tunica media (81% versus 21%; P < .001) as well as a stratum of neointimal fibrocellular hyperplasia (68% versus 7%; P < .001), which on immunohistochemistry and electron microscopy appeared to be proliferating smooth muscle cells. CONCLUSIONS: In our study population, sudden death was precipitated by acute coronary thrombosis in only 27% of patients with obstructive coronary atherosclerotic plaque. Most of the young victims of sudden death with obstructive coronary atherosclerosis showed single-vessel disease that affected the left anterior descending coronary artery and was due to fibrous plaques with neointimal smooth muscle cell hyperplasia and a preserved tunica media in the absence of acute thrombosis.

Acute Disease↗
PubMed1994

[Hemorrhagic necrotic acute pancreatitis: analysis of our case series in the light of the most recent diagnostic and therapeutic criteria].

During the period between 1-1-1979 and 30-9-1992, 43 cases of hemorrhagic necrotic acute pancreatitis were referred to the authors' attention. Six patients were not operated, 12 underwent emergency surgery and laparotomy was postponed in 25 cases. The introduction of sophisticated diagnostic methods, such as Eco, CT, ERCP, intensive medical therapy and postoperative NPT have allowed a more rational surgical approach in terms of timing and extent to be adopted, operating on patients who are metabolically more stable. NPT is a useful tool in the latter postoperative stage. In the series of patients undergoing emergency laparotomy there was a mortality rate of 66%. The mortality rate fell to 16% in those patients in whom surgery was postponed.

Acute Disease↗
PubMed1994

[Tumors of the thoracic wall. Our experience].

Chest wall tumors are rare being less than 1% of all the neoplasms. While the treatment of benign tumor and of solitary metastatic is standardized, the therapy of the primary malignant is not the same for all the authors. From January 1980 to December 1993 46 patients affected by chest wall neoplasms, 29 men (63%) and 17 women (37%), mean age of 51 yrs. (range 31-77 yrs.), were treated surgically. For benign tumors only resection was performed while for malignant and metastatic tumors after the resection the reconstruction was performed respectively: in 11 cases with Marlex mesh, in 1 case with the omentum, in 2 cases with Marlex and Methyl Methacrylate. Muscle transposition was performed in 1 case with pectoralis major covering a Dura Mater prosthesis. We have no peroperative death and no complications in 37 (80%) patients. Minor complications in 9 cases; in 1 case the sternal prosthesis was removed for infection. The median follow up was of 40.50 months. Actually the 48% of patients with primary and metastatic tumor are alive. From our results we conclude that the wide radical resection with reconstruction when necessary is the treatment of choice for the tumors of the chest wall.

Adult↗
PubMed1994

Intersubject variability of real-ear sound pressure level: conventional and insert earphones.

Measures of the sound pressure level (SPL) near the eardrum were determined at discrete frequencies between 500 and 4000 Hz on 50 ears using TDH-39P and ER-3A earphones with the attenuator of an audiometer fixed at 90 dB HL. Results revealed significant differences in the measured SPL between the two earphones at all test frequencies. Results also revealed large intersubject differences in the SPL measured near the eardrum for both earphones. The results of this study highlight the large intersubject variability associated with measuring the SPL at the eardrum and point out the difficulty in accurately predicting individual performance from averaged group data.

Amplifiers, Electronic↗
PubMed1994

[Cancer of the cervical esophagus: integrated therapy and surgical treatment].

From July 1979 to December 1990, 68 consecutive patients with resectable esophageal cancer were treated at our Institute. Until May 85 standard treatment was total laryngectomy and proximal or total esophagectomy, thereafter, to preserve the larynx, primary concomitant chemotherapy and radiotherapy followed by salvage resection in case of persistent disease or local recurrence was the standard regimen. Primary concomitant radio-chemotherapy consisted of traditional radiotherapy (30 + 20 Gy over 7 weeks) with 4 courses of chemotherapy (5FU 1000 mg/sqm 24-hour infusion, days 1 to 4 and CDDP 100 mg/sqm, day 1). 39 patients underwent standard primary total laryngo-pharyngo-esophagectomy, and after May 1985, 29 underwent standard concomitant radiochemotherapy and 16 excluded patients (5 for medical contraindications, 4 for previous partial or total laryngectomy, and the remaining 7 for location of the tumor only in the precricoid) underwent primary resection as second choice treatment. After 40 months of median follow-up 6/39 underwent salvage resection. Iatrogenic mortality (hospital and distant mortality related to the treatment) was 10% (9/68), 13% (5/39) for standard and second choice primary resection and 10% (3/29) for concomitant radiochemotherapy (2 death) and salvage resection (1 death). For overall the patients the median survival was 16 months, without any difference for the patients treated before or after May 85, with minimal difference of the rate of 5 year survival (21% vs 19%), but nearly 50% of the long survivors treated after May 85 is speaking with the larynx.

Adult↗
PubMed1994

[Value of magnetic resonance in the staging of non-small-cell lung carcinoma].

In the last six years, 544 consecutive patients with nonsmall-cell bronchogenic carcinoma were studied with MRI. MR results were compared with surgical specimens and pathologic findings. Both TNM classification and ATS nodal mapping were considered. Local tumor extent (T parameter) was correctly identified in 67.2% of cases, understaged in 19.4% and overstaged in 13.4%. Lymph node metastases (N parameter) were adequately assessed in 55.5% of cases, understaged in 20.3% and overstaged in 24.2%. Considering two groups of patients, the first one with early stage disease (T1-T2, N0-N1) and the second one with advanced stages (T3-T4, N2-N3), MRI exhibited 84.6% overall accuracy, 57.3% sensitivity and 93.7% specificity for the T parameter and 72.3% accuracy, 65.2% sensitivity and 75.1% specificity for the N parameter. In conclusion, MRI did not provide the expected results in the staging of nonsmall-cell bronchogenic carcinoma, but improvement will probably be achieved with technological evolution.

Carcinoma, Non-Small-Cell Lung↗
PubMed1994

Safety of absorbable suture for sternal closure after pulmonary or mediastinal resection.

The reliability of polyglyconate monofilament (Maxon) suture for sternal closure was tested on 216 consecutive sternotomies, performed on 208 patients in our department from January 1986 to December 1990. The reason of sternotomy was primary lung cancer in 34 cases (16%), lung metastases in 127 (59%), and disorders of the thymus in 55 (25%). Mean age was 38 years (range 3 to 78 years); multiple lung resections were performed in 102 patients (average 7 lesions, range 2 to 30); maximum extent of the operation was pneumonectomy in 2 cases, lobectomy in 53, segmentectomy in 27, and wedge resection in 74. Prior chemotherapy had been administered in 75 cases (35%). A second sternotomy was performed in 8 cases. No cases of sternal dehiscence, sternal infection, or empyema were observed, after a median follow-up of 27 months. Overall perioperative mortality was 0.9% (2/216). Our series demonstrates the safety of polyglyconate monofilament (Maxon) suture for sternal closure. Absorbable sutures appear to be a safe alternative to steel wire closure in patients undergoing extended pulmonary or mediastinal resection.

Adolescent↗
PubMed1993

Endomyocardial biopsy in right ventricular cardiomyopathy.

Right ventricular cardiomyopathy is characterized by a progressive myocyte loss and fibro-fatty substitution of the right ventricle. The aim of our study was to assess the diagnostic accuracy of right ventricular endomyocardial biopsy. Using an imaging analyser system, histomorphometric parameters of myocytes, interstitium, fibrous tissue and fatty tissue were evaluated on endomyocardial biopsy from 30 patients with arrhythmogenic right ventricular cardiomyopathy, 29 patients with dilated cardiomyopathy and 30 control patients. The percent area of myocytes decreased from 78.10 +/- 7.34 in control to 63.39 +/- 9.22 in dilated cardiomyopathy (P < 0.05) and to 47.28 +/- 15.01 in arrhythmogenic right ventricular cardiomyopathy (P < 0.01). Fibrous tissue increased from 8.10 +/- 3.89 in control to 21.80 +/- 9.29 in dilated cardiomyopathy (P < 0.05) and to 24.60 +/- 11.37 in arrhythmogenic right ventricular cardiomyopathy (P < 0.05). Fatty tissue varied from 0.33 +/- 1.44 in control and 0.07 +/- 0.31 in dilated cardiomyopathy to 13.30 +/- 17.30 in arrhythmogenic right ventricular cardiomyopathy (P < 0.05). Fatty tissue was a feature of arrhythmogenic right ventricular cardiomyopathy (67% of patients vs. 6% of control and dilated cardiomyopathy patients). Diagnostic values typifying arrhythmogenic right ventricular cardiomyopathy, obtained by excluding any overlapping between confidence intervals in the three groups, were: myocytes < 44.95%; fibrous tissue > 40.38%, and fatty tissue > 3.21%, with 67% sensitivity and 91.53% specificity for at least one parameter. In conclusion, a significant difference between arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy and control exists in terms of amount of myocytes, fibrous tissue and fatty tissue. Presence of fatty tissue and fibrous tissue exceeding 3.21% and 40.38%, respectively should be considered highly suspect for arrhythmogenic right ventricular cardiomyopathy in right ventricular endomyocardial biopsy.

Adipose Tissue↗
PubMed1993

Identification of an NADH plus iron dependent, Ca2+ activated hydrogen peroxide production in synaptosomes.

The addition of microM Ca2+ to synaptosomes incubated in the presence of EGTA and NADH activates a slow production of H2O2, which is promptly inhibited by excess EGTA and reactivated by Ca2+. The H2O2 output is inhibited by the Fe chelator deferoxamine. Higher Ca(2+)-dependent H2O2 productions are induced in the presence of added FeCl3 in the absence of lipid peroxidation. The apparent Km for Fe is 28 microM. NADH is oxidized parallel to the production of H2O2 (NADH/H2O2 = 0.82 +/- 0.1). If NADH is omitted, some H2O2 is still generated, with electrons from ferrocytochrome c; in these conditions the inhibition by excess EGTA develops slowly being completed only after some minutes. The semimaximal activation of the H2O2 production is obtained at 1-1.2 microM free Ca2+. Millimolar Ca2+ is inhibitory. After treatment with digitonin, the H2O2 production increases by 40-50%. This 'internal' H2O2 probably corresponds to the previously described Ca(2+)-ionophore-induced H2O2 generation which is observable after glutathione depletion. In no case could a production of O2- be monitored. All the synaptosomal Ca(2+)-Fe oxidase activity is recovered in the plasma membrane fractions. NADH provides most of the reducing equivalents in the heavier fraction, which is the richest in postsynaptic components. A significant proportion of the H2O2 production utilizes electrons from cytochrome c in the lighter plasma membrane fractions.

Animals↗
PubMed1993

Functional and morphological effects of defibrotide on renal ischemia.

Defibrotide (Df) has been reported to protect various organs from ischemic damage. The aim of this study was to evaluate the effect of Df on renal function and morphology after warm kidney ischemia. Divided into two groups, 14 pigs underwent bilateral renal clamping for 90 min. One group (7 pigs) was treated with Df (32 mg/kg per h) for 6 h, whereas the control group received 5000 IU of heparin. Serum levels of blood urea nitrogen (BUN) and creatinine measured for 6 days were significantly higher in the control group (peak 26.8 +/- 16.7 vs 11.0 +/- 2.9 mmol/l and 501.2 +/- 351.4 vs 230.2 +/- 68.0 mumol/l P < 0.05). Renal biopsy evidenced a lesser extent of tubular and endothelial damage in Df-treated animals. In conclusion, Df provided relevant protection against renal ischemic injury.

Animals↗
PubMed1993

Adjuvant treatment of stage I lung cancer with high-dose vitamin A.

PURPOSE: Vitamin A and retinoids are strong inhibitors of epithelial cancer promotion and progression in experimental carcinogenesis. This study examined whether they may prevent the occurrence of upper aerodigestive cancer in subjects heavily exposed to tobacco smoking, such as patients already cured of an early-stage lung cancer. PATIENTS AND METHODS: The adjuvant effect of high-dose vitamin A was tested on 307 patients with stage I non-small-cell lung cancer. After curative surgery, patients were randomly assigned to either a group prescribed retinol palmitate administration (orally 300,000 IU daily for 12 months) or a control group prescribed no treatment. RESULTS: After a median follow-up of 46 months, the number of patients with either recurrence or new primary tumors was 56 (37%) in the treated arm and 75 (48%) in the control arm. Eighteen patients in the treated group developed a second primary tumor, and 29 patients in the control group developed 33 second primary tumors. A statistically significant difference in favor of treatment was observed concerning time to new primary tumors in the field of prevention (P = .045, log-rank test). The treatment difference in terms of disease-free interval was close to statistical significance (P = .054, log-rank test) and just significant when adjusted for primary tumor classification (P = .038, Cox regression model). CONCLUSION: Daily oral administration of high-dose vitamin A is effective in reducing the number of new primary tumors related to tobacco consumption and may improve the disease-free interval in patients curatively resected for stage I lung cancer. The impact of such a treatment on survival needs to be further explored.

Adolescent↗
PubMed1993

[The nutritional aspects in autologous bone marrow transplantation].

The use of total parenteral nutrition (TPN) in bone marrow transplant recipients is well recognized. These patients, as a result of treatment with chemotherapy and immunosuppressive agents, undergo catabolic stress. In stressed patients attention has been focused on the optimal calorie: nitrogen ratio of total parenteral nutrition formulations. Theoretically, TPN formulas of low calorie: nitrogen ratio impede body protein catabolism. In bone marrow transplant patients negative nitrogen balance may persist despite high nitrogen intake. The purpose of the present study is to determine the effect of increasing nitrogen intake on nutritional and metabolic parameters in bone marrow transplant patients. The metabolic effect of an increased nitrogen dose during TPN was studied in 33 bone marrow transplant patients, divided into 2 groups. Patients were given total parenteral nutrition formulas providing a protein intake of 1.4 +/- 0.2 g of protein/kg IBW/day for the first group, and 2.3 +/- 0.12 g of protein/kg IBW/day for the II group. Total calories, non protein and protein, were held constant at 40 kcal/kg IBW/day for all patients. Data have been calculated for 4 weeks starting from the first week pretransplant. As we had expected, the patients who are the object of the present study were well nourished at the time of hospital admission, confirming the description of bone marrow transplant recipients published by other transplant centers. Relative body weight, total serum protein, albumin, prealbumin and cholesterol were not significantly different at any study period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[The early and late complications after percutaneous balloon coronary angioplasty].

The coronary arteries from the hearts of 7 patients, 6 male and 1 female, age ranging from 39 to 69 years (mean 56), who died early or in the mid term from percutaneous transluminal coronary angioplasty (PTCA), were investigated by histology, immunohistochemistry and electron microscopy. Atherosclerotic coronary artery disease was present in all: single vessel disease in 2 and double vessel disease in 5. Indication to PTCA was stable angina in 1 patient, unstable angina in 2, postinfarction angina in 2 and acute myocardial infarction in the remaining 2. Thrombolysis was an associated procedure in 3 cases. Time interval between PTCA and death was less than 48 hours in 6, and 4 months in 1. Cause of death was myocardial infarction due to coronary occlusion complicating PTCA in 3 patients, and myocardial infarctions preceding PTCA in 4 patients. 9 coronary segments underwent dilatation: 5 in the anterior descending coronary artery, 3 in the right coronary artery and 1 in the left circumflex artery. Angiographically, the PTCA had been effective (decrease of stenosis > or = 40%) in 5 and failed in 4. Basically, the atherosclerotic plaques were eccentric in 3 and concentric in 6; the histotype was fibrotic in 4, atheromatous in 4 and fibro-atheromatous in 1. Only one case did not show any complication and the dilatation was effective as a consequence of plaque compression and stretching of the underlying tunica media. Complications observed in the other cases with early death consisted of: a) plaque cracks with intimal flaps and hematomas in all 6; b) laceration of the tunica media, even of the disease-free wall, with dissecting hematoma in 2; c) occlusive thrombosis in 3 and d) atheroembolism in 1. The 4 coronary segments, which appeared occluded angiographically soon after PTCA, were clinically interpreted as dissection in 3 and thrombosis in 1, whereas at histology the closing mechanism was an intimal hematoma with flap in 2, occlusive thrombosis in 1, and medio-adventitial dissecting hematoma with thrombosis in 1. Only ruptures of atheromatous plaques were complicated by thrombosis. The patient who died at 4 months exhibited a pattern of restenosis due to intimal smooth muscle cell proliferation. In conclusion, our postmortem study shows that PTCA may be associated with severe damage of the coronary artery consisting of plaque crack and laceration even of the disease-free wall, intimal and medial hematomas, thrombosis and atheroembolism.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1993

Cardiac fibroma and heart transplantation.

Successful orthotopic heart transplantation was performed in a 38-day-old child with a fetal echocardiographic diagnosis of a left ventricular mass and in a 40-year-old woman with cardiac murmur since childhood and an echocardiographic diagnosis of asymmetric septal hypertrophy. Pathologic examination of the removed hearts, consisting of gross, histologic, immunohistochemical, and ultrastructural studies, led to the final diagnosis of cardiac fibroma. Both patients were alive and in good condition at 35 and 28 months, respectively, after operation.

Adult↗