Search PubMed⌕ Search

Biomedical subjects

M Rossi

Publications and source records attributed to M Rossi.

At least 235 records · Page 13Linked to original sources
PubMed1999

Medical negligence in Italy: the criminal inquiry.

In the past decade, there has been an exponential increase in legal proceedings against doctors due to allegations of medical negligence. The via crucis of the doctor under investigation for alleged medical negligence in Italy is little known beyond the Alps. The authors hope this paper will bring to the attention of medical and legal colleagues this complex issue of the process followed by the justice machinery in Italy where the criminal route in pursuit of justice is the norm.

Humans↗
PubMed1999

Local invasion of gastric cancer: CT findings and pathologic correlation using 5-mm incremental scanning, hypotonia, and water filling.

OBJECTIVE: Our purpose was to assess the accuracy of CT with drug-induced hypotonia and water filling in revealing the depth of tumor invasion of the gastric wall, according to the T factor of TNM classification, and to verify the capability of this technique in differentiating diffuse from intestinal gastric cancer. SUBJECTS AND METHODS: Forty patients (age range, 35-78 years) with histologically proven gastric tumors underwent CT, in the prone position, with drug-induced hypotonia and water filling. The images were prospectively reviewed by two radiologists who were asked to assess the depth of tumor invasion in the gastric wall. The thickening of the hypodense layer and the contrast enhancement of lesion were measured. RESULTS: CT correctly assessed gastric wall invasion in 77% and 82% of cases for observers A and B, respectively; overstaging was 20% and 15%, respectively; and understaging occurred in 3% of cases for both observers. Diagnostic sensitivity for serosal invasion was 100% for both observers; specificity was 80% and 87%, respectively. Substantial agreement between the observers was obtained (kappa = .6). Diffuse and intestinal cancers could be differentiated by CT in 92% of cases, considering the thickening of the hypoattenuating layer of the gastric wall (diffuse cancer: 7 +/- 1.2 mm; intestinal cancer: 1.4 +/- 0.4 mm) and contrast enhancement (diffuse cancer: 85 +/- 8.2 H; intestinal cancer: 51 +/- 3 H). CONCLUSION: CT with patients in a drug-induced hypotonia and in a prone position, and using water filling, is a promising technique for evaluating the depth of tumor invasion and for differentiating intestinal from diffuse gastric cancer.

Adult↗
PubMed1999

MR cholangiography of late biliary complications after liver transplantation.

OBJECTIVE: The aim of our study was to assess the role of MR cholangiography in the diagnosis of late biliary complications after liver transplantation. SUBJECTS AND METHODS: Twenty-three liver transplantation patients (18 men and five women; mean age, 46 years) underwent MR cholangiography using a nonbreath-hold, fat-suppressed three-dimensional turbo spin-echo sequence (TR/TE, 3000/700; echo train length, 128) optimized on a 0.5-T magnet. Inclusion criteria were liver function tests with abnormal results and hyperbilirubinemia with a clinical pattern not specific for biliary obstruction. All patients were referred by clinicians for contrast-enhanced cholangiography. Diagnostic confirmation was obtained with percutaneous transhepatic cholangiography (n = 4), endoscopic retrograde cholangiography (n = 8), T-tube cholangiography (n = 1), or clinical follow-up (n = 10). RESULTS: In 11 patients, no abnormalities of the biliary tract were revealed by MR cholangiography. In 11 patients, twelve strictures were diagnosed (nine anastomotic, two nonanastomotic-intrahepatic, and one nonanastomotic-extrahepatic, with association between anastomotic and nonanastomotic strictures in two cases). In one other patient, kinking of the common bile duct at the level of the anastomosis was observed. In all cases, MR cholangiography correctly showed the site of the stricture and the dilatation of bile ducts above, with excellent correlation with contrast-enhanced cholangiographic findings. Strictures were correctly graded in eight of 10 patients and were overestimated in two. Other findings included a 1-cm stone detected proximal to the obstructed common bile duct in one patient and multiple intrahepatic stones in another patient. CONCLUSION: MR cholangiography can show biliary obstruction and provide important information for planning therapeutic procedures.

Adult↗
PubMed1999

Recurrence of hepatitis C virus infection after orthotopic liver transplantation: role of genotypes.

In this study, we evaluated the correlation between alanine aminotrasferase levels and hepatitis C virus genotypes in liver transplant patients. We studied 18 patients who had undergone orthotopic liver transplantation because of end-stage cirrhosis (n = 9) or hepatocellular carcinoma (n = 9) hepatitis C virus related. Serum HCV-RNA testing was performed monthly on all the 18 series of serum samples from the first week after liver transplant until the end of the follow up, this period ranging from 1 to 39 months. After liver transplantation, serum HCV-RNA was detected in 14 patients (78%). Of the 8 patients infected with subtype 1b. 1 remained asymptomatic, 2 developed acute liver failure and 5 developed chronic hepatitis. In patients infected with types 1a (Choo et al., 1989), 2a (Choo et al., 1989), with a mixed infection 1b/3 (Kuo et al., 1989) or with an undetermined genotype, significant laboratory abnormalities were not observed. Recurrence of hepatitis C virus infection after liver transplantation is common, and recurrent hepatitis occurs in 50% of cases. Genotype 1b appears to be associated with a higher rate of recurrent hepatitis, compared to other genotypes.

Adult↗
PubMed1999

Different effects of microwave energy and conventional heat on the activity of a thermophilic beta-galactosidase from Bacillus acidocaldarius.

The effect of microwave (f = 10.4 GHz) irradiation on a thermostable enzyme was experimentally tested, showing that irreversible inactivation is obtained. Enzymatic solutions (500 microliters, with concentrations between 10-100 micrograms/ml) were exposed at 70 degrees C, at SAR levels of 1.1 and 1.7 W/g for 15, 30, 45, or 60 min, and their activity was compared to that of a sample heated in a water bath at the same temperature. The residual activity of the exposed samples depends on enzyme concentration, microwave power level, and exposure time; activity was reduced to 10% in 10 micrograms/ml solutions treated at 1.7 W/g for 60 min. Microwave effects disappeared at concentrations above 50 micrograms/ml. These results were not found following water bath heating at the same temperature and durations.

Bacillus↗
PubMed1999

Perioperative management of a patient with Werlhof disease undergoing myocardial revascularization.

We herein report the case of a patient with idiopathic thrombocytopenic purpura (Werlhof disease) and coronary artery disease undergoing myocardial revascularization. The use of monomeric immunoglobulins, corticosteroids, platelets transfusion, use of a cell saver, normothermic cardiopulmonary bypass, aprotinine and homologous blood transfusion were combined in order to minimize the risk of bleeding complications in the postoperative period.

Aged↗
PubMed1999

Ultrastructural alterations in the adrenal gland cortex of mice experimentally infected with a Venezuelan isolate of Trypanosoma evansi.

The ultrastructural study of adrenal gland from mice experimentally infected with Trypanosoma evansi, in addition to intravascular and intracellular trypanosomes, showed different degrees of cortical cell alterations and capillary wall modifications. Beside its biological scope, these results suggest a role for the adrenal cortex to partake in Surra's etiopathogenesis and describe for the very first time a T. evansi intracellular stage.

Adrenal Cortex↗
PubMed1999

Cystic lymphocytic hypophysitis, visual field defects and hypopituitarism.

A 45-year-old man presented with anterior pituitary failure, requiring thyroxine, hydrocortisone and androgen replacement. An MRI scan revealed a large cystic pituitary mass and thickening of the pituitary stalk. Over three years, diabetes insipidus and bitemporal hemianopia developed and the cystic mass had enlarged on MR scanning. Transphenoidal resection was performed with normalisation of the visual fields. Histology revealed lymphocytic hypophysitis, which is rare in men. The presentation with cystic enlargement is unique.

Diabetes Insipidus↗
PubMed1999

Endobronchial granular cell tumour.

Granular cell tumour of the lung is a rare benign tumour. We report a case of endobronchial granular cell tumour which occurred in a 70-yr-old male with haemoptysis. Because of the size of the tumour (greater than 8 mm) and the associated pseudoepitheliomatous hyperplasia with marked atypia, surgical resection was performed. No neoplastic relapse has been observed in nearly 4 yrs of follow-up.

Aged↗
PubMed1998

Restoration of the activity of active-site mutants of the hyperthermophilic beta-glycosidase from Sulfolobus solfataricus: dependence of the mechanism on the action of external nucleophiles.

The beta-glycosidase from the hyperthermophilic Archaeon Sulfolobus solfataricus hydrolyzes beta-glycosides following a retaining mechanism based upon the action of two amino acids: Glu387, which acts as the nucleophile of the reaction, and Glu206, which acts as the general acid/base catalyst. The activities of inactive mutants of the catalytic nucleophile Glu387Ala/Gly were restored by externally added nucleophiles. Sodium azide and sodium formate were used as external nucleophiles and the products of their reaction were characterized. Glu387Ala/Gly mutants were reactivated with 2, 4-DNP-beta-Glc substrate and the Glu387Gly mutant showed recovered activity, with the same nucleophiles, also on 2-NP-beta-Glc. The reaction catalyzed by the Glu387Gly mutant proceeded differently depending on the type of externally added nucleophile. Sodium azide restored the catalytic activity of the mutant by attacking the alpha-side of the anomeric carbon of the substrates, thereby yielding an inverting glycosidase. Sodium formate promoted the opposite behavior (retaining) in the mutant, producing 3-O-beta-linked disaccharide derivative of the substrates. A possible role of sodium formate as a biomimicking agent in replacing the natural nucleophile Glu387 is also discussed.

Binding Sites↗
PubMed1998

Amino acid residues involved in determining the processivity of the 3'-5' exonuclease activity in a family B DNA polymerase from the thermoacidophilic archaeon Sulfolobus solfataricus.

Herein, we report on the mutational analysis of a 70-amino acid segment (region 1, residues 438-508) of family B DNA polymerase from the thermoacidophilic archaeon Sulfolobus solfataricus (Sso DNA pol). Region 1, which lies between the Exo III sequence and the similarity motif D- -SLYP, connects the exonuclease and polymerase domains of Sso DNA pol. Two C-terminally deleted forms of the enzyme, proteins N438 (residues 1-438) and N508 (residues 1-508), were overproduced in the recombinant form and biochemically characterized. They contain the three evolutionarily conserved Exo motifs, but differ in the extent of the C-terminal deletion, since only N508 includes region 1. Both have been found to retain a Mn2+-dependent 3'-5' exonuclease activity, whose thermal stability appears to be increased in comparison to that of the full-sized enzyme. Assays for processive 3'-5' exonuclease activity, carried out with the heparin trap method on a 24-base oligonucleotide, have revealed that protein N508, as well as the full-length Sso DNA pol, retains a level of processivity of the degradative function substantially higher than that for protein N438. In addition, six site-specific mutations have been introduced at the highly conserved Y-GG/A motif, which has been found within Sso DNA pol region 1. All mutant proteins (Lys491Ile, Tyr495Ser, Lys496Ile, Gly497Ala, and Ala498Val) display increased processivity of their 3'-5' exonuclease activity, with the exception of protein Tyr495Phe. By a steady-state kinetic analysis of the exonucleolytic reaction on a 24-base oligonucleotide, the above site-specific mutations have been found to affect Km values consistently with the observed differences in the processivity values, whereas the effect on the kcat values seems to be less important. The results from this mutational analysis indicate that region 1 is involved in determining the processivity of the proofreading function, directly interacting with the nucleic acid substrate.

Amino Acids↗
PubMed1998

Guanidine-induced denaturation of beta-glycosidase from Sulfolobus solfataricus expressed in Escherichia coli.

Guanidine-induced denaturation of Sulfolobus solfataricus beta-glycosidase expressed in Escherichia coli, Sbetagly, was investigated at pH 6.5 and 25 degreesC by means of circular dichroism and fluorescence measurements. The process proved reversible when the protein concentration was lower than 0.01 mg mL-1. Moreover, the transition curves determined by fluorescence did not coincide with those determined by circular dichroism, and the GuHCl concentration corresponding at half-completion of the transition increased on raising the protein concentration in the range 0.001-0.1 mg mL-1. Gel filtration chromatography experiments showed that, in the range 2-4 M GuHCl, there was an equilibrium among tetrameric, dimeric, and monomeric species. These findings, unequivocally, indicated that the guanidine-induced denaturation of Sbetagly was not a two-state transition with concomitant unfolding and dissociation of the four subunits. A mechanism involving a dimeric intermediate species was proposed and was able to fit the experimental fluorescence intensity transition profiles, allowing the estimation of the total denaturation Gibbs energy change at 25 degreesC and pH 6.5. This figure, when normalized for the number of residues, showed that, at room temperature, Sbetagly has a stability similar to that of mesophilic proteins.

Chromatography, Gel↗
PubMed1998

The NPY Y1 receptor antagonist BIBP 3226 blocks NPY induced feeding via a non-specific mechanism.

We have previously shown that intracerebroventricular BIBP 3226 inhibits NPY induced feeding in rats. However, this was associated with abnormal behaviour, likely to be due to interaction with Y1 receptors involved in mechanisms other than the control of food intake. In order to minimise such interactions we investigated the effects of paraventricular nucleus (PVN) injections of BIBP 3226 and its inactive enantiomer BIBP 3435. Intra-PVN injection of NPY (0.1-2.5 nmol/animal) increased food intake, with an EC50 of approximately 0.15 nmol/animal. Injections of BIBP 3226 and BIBP 3435 (0.25-25 nmol) reduced NPY-induced food intake in a dose responsive manner, with BIBP 3226 reducing food intake by 95%, and BIBP 3435 by 65% at the highest dose tested. The reversibility of the effect of BIBP 3226 was investigated by measuring the feeding response to NPY (0.5 nmol) in animals 1 week after BIBP 3226 injection. The response to NPY was less in animals which had received high doses of BIBP 3226. Animals previously injected with saline vehicle alone showed a normal NPY feeding response. These results suggest that BIBP 3226 may be inhibiting NPY-induced food intake in a non-specific manner, not secondary to inhibition of the Y1 receptor. This does not, however rule out a role for the Y1 receptor in the control of food intake by NPY.

Animals↗
PubMed1998

Crystallization and preliminary X-ray diffraction studies of DNA polymerase from the thermophilic archaeon Sulfolobus solfataricus.

The thermophilic and thermostable family B DNA polymerase from the archaeon Sulfolobus solfataricus (Mr of about 100 kDa) has been crystallized by the hanging-drop vapour-diffusion method at 294 K using ammonium sulfate as precipitant. The crystals belong to the monoclinic space group C2 with cell dimensions a = 187.4, b = 68.5, c = 125.8 A and beta = 107.8 degrees and diffract up to 2.7 A resolution on a rotating-anode X-ray source. Native data have been collected at 100 K. A heavy-atom derivative search is in progress.

Bacterial Proteins↗