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Biomedical subjects

M Valente

Publications and source records attributed to M Valente.

At least 55 records · Page 3Linked to original sources

Gastrointestinal infection due to Anisakis simplex in southern Italy.

The authors present four cases of infection due to Anisakis in an area where people are prone to infectious diseases transmitted by raw fish, but in which the presence of this parasite has never been reported. Three of four cases were discovered accidently during surgical procedures for co-existing abdominal pathologies. Raw fish was apparently not involved in all patients. Characteristics of the patients are discussed.

Adult↗

Liver cell apoptosis in chronic hepatitis C correlates with histological but not biochemical activity or serum HCV-RNA levels.

In hepatitis C virus (HCV) infection, mechanisms responsible for liver cell damage are still poorly understood and both necrosis and apoptosis may be operative. By using terminal deoxynucleotydil transferase-mediated d-UTP-biotin nick-end labeling (TUNEL) we have evaluated and quantified apoptosis in liver biopsy specimens from 61 patients with chronic hepatitis C. All patients had detectable apoptotic cells in the liver. Presence of increased apoptotic activity was confirmed in selected cases by electron microscopy and by DNA gel electrophoresis. The amount of liver cell apoptosis expressed as apoptotic index, ranged between 0.01% to 0.54% and showed a positive correlation with histological activity grading (P <.0005) and with the amount of infiltrating CD8-positive cells (P =. 01). Apoptosis did not correlate with transaminase levels or with HCV load and genotype. These results support the concept that immune-mediated apoptosis may play a role in the pathogenesis of chronic hepatitis C and indicate that this type of reaction may occur in the absence of significant alanine transaminase (ALT) elevation, thus explaining the lack of correlation between biochemical activity and liver histological damage.

Adolescent↗

Spontaneous apoptosis and proliferation in human pancreatic cancer.

Several studies have documented the role of programmed cell death in the development and/or progression of cancer. The aims of this study were to analyze (a) the spontaneous apoptosis in human pancreatic duct carcinoma by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-digoxigenin nick end labeling (TUNEL); (b) its correlation with the proliferation rate of the tumor (determined by immunohistochemistry by using monoclonal antibody MIB-1); and (c) the association of apoptotic and mitotic index with the histologic features of the tumor and the outcome of patients. In pancreatic cancer, the apoptotic index (AI) was 4.9 +/- 4.8, and the mitotic index (MI) was 1.3 +/- 1.0 (mean +/- SD). AI was higher in small (<4 cm) than in large (>4 cm) size primary tumors (p = 0.02) and in undifferentiated as compared with differentiated cancers (p = 0.05). Significantly higher values of MI were detected in advanced as compared with early-stage carcinomas (p = 0.03) and when perineural invasion was present (p = 0.03). No correlation was found between AI and MI. Patients with AI > 2.3 survived significantly less than those with lower AI values (p = 0.03). Mitotic index >0.5 was associated with a worse survival (p = 0.006). These results suggest that in pancreatic cancer, spontaneous apoptosis is present and is more evident in small and undifferentiated tumors. Proliferation is increased in the advanced stage of cancer and seems to be independent of apoptosis. Higher levels of apoptosis and proliferation are negative prognostic indexes.

Adult↗

Thermus igniterrae sp. nov. and Thermus antranikianii sp. nov., two new species from Iceland.

Several yellow-pigmented isolates, with optimum growth temperatures of about 65-70 degrees C, were recovered from hot springs in Iceland. Phylogenetic analysis of the 16S rDNA and DNA-DNA reassociation values showed that these organisms represented two new species of the genus Thermus. Strains RF-4T and HN1-8 had maximum temperatures for growth below 80 degrees C, while strains HN3-7T and HN2-7, unlike all other strains of the species of the genus Thermus except those belonging to Thermus thermophilus, grew at 80 degrees C. The new isolates from Iceland could not be distinguished easily from each other or from other strains of the species of the genus Thermus by biochemical characteristics; however, strains RF-4T and HN1-8 assimilated ribitol, a characteristic which was not detected in any of the other strains examined. Moreover, the species represented by strains RF-4T and HN1-8 and the species represented by strains HN3-7T and HN2-7 could be distinguished clearly from the other species of Thermus by their fatty acid composition. Strains RF-4T and HN1-8 have the highest combined levels of iso-15:0 and iso-17:0 and the lowest levels of iso-16:0 of any of the strains of the species of Thermus, while strains HN3-7T and HN2-7 are characterized by a very low iso-15:0/iso-17:0 ratio. On the basis of the phylogenetic analysis, DNA-DNA reassociation values, physiological and biochemical characteristics and fatty acid composition, the name Thermus igniterrae sp. nov. is proposed for the species represented by strains RF-4T and HN1-8 and the name Thermus antranikianii sp. nov. is proposed for the species represented by strains HN3-7T and HN2-7.

Base Composition↗

No detection of enteroviral genome in the myocardium of patients with arrhythmogenic right ventricular cardiomyopathy.

AIMS: Despite the evidence of familial occurrence, chromosomal gene mapping, and apoptosis as a mechanism of myocyte death, the aetiopathogenesis of arrhythmogenic right ventricular cardiomyopathy (ARVC) remains speculative. Because of the frequent histological finding of focal inflammatory infiltrates, the hypothesis of an infective myocarditis aetiology has been put forward. The aim of this investigation was to test this hypothesis. The presence of enteroviruses was investigated by a highly sensitive and specific molecular technique. METHODS: Endomyocardial tissue samples from 20 patients with ARVC (11 male, nine female; mean age, 40 years; SD, 16) and 20 control subjects with other cardiac diseases were analysed using reverse transcription and nested polymerase chain reaction (PCR). Myocardial samples obtained from four patients with enteroviral myocarditis and coxsackie B3 virus infected cells were used as positive controls. RESULTS: Endomyocardial biopsy was diagnostic for ARVC in all patients: myocardial atrophy was seen, with less than 45% residual myocytes. Foci of inflammatory infiltrates were seen in four biopsies, and the cells were identified by immunohistochemistry as mainly T cells. All samples, from both patients with ARVC and subjects with other cardiac diseases, were negative for enteroviral genome by means of nested PCR. CONCLUSION: These findings indicate that enteroviruses are not involved in the aetio-pathogenesis of ARVC. Future molecular studies should investigate the presence of other infective agents, as well as their possible role in triggering apoptosis.

Adult↗

A selective inhibitor of the osteoclastic V-H(+)-ATPase prevents bone loss in both thyroparathyroidectomized and ovariectomized rats.

A potent and selective inhibitor of the osteoclastic V-H(+)-ATPase, (2Z,4E)-5-(5,6-dichloro-2-indolyl)-2-methoxy-N-(1,2,2,6, 6-pentamethylpiperidin-4-yl)-2,4-pentadienamide (SB 242784), was evaluated in two animal models of bone resorption. SB 242784 completely prevented retinoid-induced hypercalcemia in thyroparathyroidectomized (TPTX) rats when administered orally at 10 mg/kg. SB 242784 was highly efficacious in the prevention of ovariectomy-induced bone loss in the rat when administered orally for 6 months at 10 mg/kg/d and was partially effective at 5 mg/kg/d. Its activity was demonstrated by measurement of bone mineral density (BMD), biochemical markers of bone resorption, and histomorphometry. SB 242784 was at least as effective in preventing bone loss as an optimal dose of estrogen. There were no adverse effects of compound administration and no effects on kidney function or urinary acidity. Selectivity of the inhibitor was further studied using an in situ cytochemical assay for bafilomycin-sensitive V-H(+)-ATPase using sections of osteoclastoma and numerous other tissues. SB 242784 inhibited the osteoclast enzyme at 1,000-fold lower concentrations than enzymes in any of the other tissues evaluated. SB 242784 demonstrates the utility of selective inhibition of the osteoclast V-H(+)-ATPase as a novel approach to the prevention of bone loss in humans.

Acids↗

Brain abscess by citrobacter diversus in infancy: case report.

Citrobacter diversus is closely related to brain abscess in newborn infants. We describe a case of brain abscess by this bacteria in a newborn infant and his clinical and cranial computed tomographic evaluation until the fourth month of life and discuss therapeutic management of this patient.

Brain Abscess↗

Performance of dual-microphone in-the-ear hearing aids.

Fifty subjects with mild to moderate-severe sensorineural hearing loss and prior experience with binaural amplification were evaluated at two sites (25 subjects at each site). Signal-to-noise ratios (SNRs) were measured using the Hearing in Noise Test (HINT) after each subject wore binaural in-the-ear hearing aids programmed for omnidirectional and dual-microphone performance, for 4 weeks. Both microphone conditions were evaluated under "ideal" (signal at 0 degrees; noise at 180 degrees) and "diffuse" (signal at 0 degrees; correlated noise at 45 , 135 degrees, 225 degrees, and 315 degrees) listening conditions. Results revealed statistically significant mean improvements in SNRs between 3.7 and 3.5 dB at Site I and 3.2 and 2.7 dB at Site II for the ideal and diffuse listening conditions, respectively, for the dual-microphones in comparison to the performance provided by the omnidirectional microphone.

Adult↗

Evaluation and treatment of severe hyperacusis.

A 52-year-old male was evaluated by the authors after initially reporting fullness in his left ear while traveling on an airplane. A unique feature of the patient's complaint was the development of severe bilateral hyperacusis (loudness discomfort levels of between 20-34 dB HL) in spite of the fact that the hearing loss was initially reported in the left ear. To achieve loudness comfort, the patient was initially fit with ER-25 musician earplugs that proved to be unsuccessful. The patient next purchased earplugs and earmuffs from a gun shop in order to obtain relief from the pain and discomfort caused by his exposure to everyday environmental sounds. This paper describes the use of hearing devices that proved to be effective in providing attenuation sufficient that the patient rarely needs to rely on earplugs and earmuffs for relief from his hyperacusis.

Anti-Inflammatory Agents↗

Clinics in diagnostic imaging (52). Spinal cord schistosomiasis.

A 2-year-old Brazilian boy presented with bilateral leg weakness and constipation, followed by development of progressive paraparesis and bladder dysfunction. Neurological examination revealed flaccid paraparesis. Blood tests and CSF analysis showed eosinophilia. The MR examination revealed a spinal cord mass extending from T9 to L1 levels, with a heterogeneously-enhancing solid component and a cystic component. Stool tests for Schistosoma mansoni eggs were positive. The patient underwent surgery, the intramedullary mass was partially resected, and the diagnosis of spinal cord infection by Schistosoma mansoni was confirmed. After surgery, the patient was treated with praziquantel and oxamniquine. He was discharged with partial improvement of the lower extremity weakness and bowel/bladder function. The clinical and imaging features of spinal cord schistosomiasis are reviewed.

Child, Preschool↗

Modulation of glutamate exocytosis by redox changes of superficial thiol groups in rat cerebrocortical synaptosomes.

The treatment of cerebral cortex synaptosomes with the membrane impermeable thiol reagent 5,5'-dithio-bis-(2-nitrobenzoic acid) (DTNB) induces a long-lasting partial inhibition (about 40%) of the KCl-stimulated Ca2+-dependent exocytosis of glutamate. Synaptosomes are not damaged by the treatment. The increase of cytoplasmic free Ca2+ concentration ([Ca2+]i) upon depolarization is not affected by DTNB. The inhibition is observed also if exocytosis is induced with the Ca2+-ionophore ionomycin. In all cases the inhibition is reversed by the impermeable reductant glutathione (GSH). Similarly the inhibition of exocytosis by H2O2 (Zoccarato, F., Valente, M. and Alexandre, A., Hydrogen peroxide induces a long-lasting inhibition of the Ca2+-dependent glutamate release in cerebrocortical synaptosomes without interfering with cytosolic Ca2+. J. Neurochem., 64 (1995) 2552-2558.) is reversed by GSH. It is concluded that redox changes (possibly thiol-disulfide transitions) of superficial groups modulate the exocytotic apparatus directly. In an attempt to identify the protein(s) involved in this novel type of control, we evidenced DTNB (H2O2) reactive bands at 35 and at 85-150 kDa which can be labeled with a monobromotrimethylammoniobimane bromide (qBBr) derivatization.

Animals↗

Enteroviral genome in native hearts may influence outcome of patients who undergo cardiac transplantation.

The Enterovirus may be the most common agent responsible for viral myocarditis and cardiomyopathy. Very little of the literature is available concerning the follow-up of patients who underwent transplantation with enteroviral positivity in native hearts. In the present study, 45 explanted hearts from patients who underwent orthotopic heart transplant at University of Padova were studied by reverse transcriptase (RT)-polymerase chain reaction (PCR): 27 patients had dilated cardiomyopathy (DC), 12 had ischemic cardiopathy (IC), 2 had valvular disease (VD), 2 had arrhythmogenic right ventricular cardiomyopathy (ARVC), 1 had giant cell myocarditis (GCM), and 1 had lymphocytic myocarditis (LM). Two sets of PCR primers from the highly conserved region of Enterovirus and Rhinovirus were used. Samples of both ventricles and septum were analyzed in every patients. The RT-PCR and nucleotide sequencing of amplicons were also performed on all post-transplantation follow-up biopsies in patients with Enterovirus positivity in the native heart. The viral genome was detectable in only 1 of 27 patients with DC (3%) and in 1 patient with LM. Nucleotide sequence analysis of the amplified product showed differences in nucleotide sequence of PCR samples compared with the sequence of the coxsackievirus B3 used in the current study. The patient with Enterovirus-positive DC showed a higher index of severe rejection (>3A) in the first 6 months, compared with the other patients tested. The patient with Enterovirus-positive LM died of disease recurrence 2 months after transplantation. The present study reveals a scarce presence of Enterovirus in the myocardium of patients with chronic myocardial disease. Because Enterovirus infection was predictive of a poor prognosis in these two patients, molecular studies are useful in excluding viral involvement in native hearts of transplanted patients.

Adolescent↗

Social context and consumption of unfamiliar foods by capuchin monkeys (Cebus apella) over repeated encounters.

Visalberghi and Fragaszy [Animal Behaviour 49:1089-1095, 1995] have shown that social influences affect acceptance of novel foods. However, little is known about the temporal course on which such influences act (e.g., for how long they persist and for how many encounters they are effective). To explore this issue, 11 adult tufted capuchins were observed during ten successive encounters with eight unfamiliar foods (phase 1, in which subjects were tested in social or individual condition) and ten more encounters 6 months later (phase 2, in which all subjects were tested in social condition). A total of 680 observational sessions were carried out. Results show that during the first five encounters in phase 1, capuchins ate more when they encountered these foods in the presence of their groupmates than if they encountered them alone. Thereafter, during the second five encounters of phase 1, foods were consumed equivalently whether presented to monkeys socially or individually. In phase 2, the foods were consumed equivalently regardless of the previous circumstance of their presentation (social or alone). In phase 2, consumption was similar to that scored in a previous study for familiar foods [Visalberghi & Fragaszy, Animal Behaviour 49:1089-1095, 1995]. We conclude that 1) foods remain unfamiliar to capuchins only for the first few encounters, 2) social facilitation of consumption of unfamiliar foods is of limited duration, and 3) individuals consumed equivalent amounts of an unfamiliar food when they repeatedly encountered it alone or in the presence of groupmates. These results caution those who interpret similar feeding habits in primate groups as evidence of social influences.

Animals↗