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Biomedical subjects

M Visconti

Publications and source records attributed to M Visconti.

At least 37 records · Page 2Linked to original sources
PubMed1992

High-performance liquid chromatographic determination of rufloxacin and its main active metabolite in biological fluids.

A high-performance liquid chromatographic method is described for the determination of a fluoroquinolone, rufloxacin, and its N-desmethyl metabolite in plasma, urine and bile. Samples are chromatographed on a poly(styrene-divinylbenzene) column, the eluate being monitored with a fluorescence detector. The method was validated and a detection limit of 10 ng/ml for both rufloxacin and its metabolite in all the biological matrices considered was found. The method was successfully applied in pharmacokinetic studies.

Anti-Infective Agents↗
PubMed1992

A structural study on elcatonin, a novel synthetic analogue of eel calcitonin, by fast atom bombardment and tandem mass spectrometry.

Elcatonin (ELC), a synthetic analogue of eel calcitonin, successfully used in the treatment of diseases characterized by an increase of osteoclastic activity, has been fully sequenced by combined enzymatic hydrolysis and fast atom bombardment (FAB) mass spectrometric methodology. The FAB mass spectrometric analysis on the entire molecule gave only the cluster corresponding to the molecular ion. Digestion with trypsin afforded four oligopeptides corresponding to fragments 1-11, 12-18, 19-24 and 25-32. B/E daughter ion analysis performed in turn on each protonated molecule ion in the tryptic mixture allowed complete sequencing of fragments 1-11 and 12-18, while in fragments 19-24 and 25-32 the portions 23-24 and 25-26 remained respectively unclarified. Investigation on the single oligopeptide isolated by preparative high-performance liquid chromatography and chymotryptic digestion of the molecule failed to provide any new information. One step of Edman degradation on tryptic digest permitted attribution of the 25-26 sequence to Thr-Asp. The connectivity between tryptic ELC fragments and the 23-24 sequence were proved by cleavage with V8 protease, which gave the oligopeptides 1-15 and 16-32. These were exhaustively analysed by FAB mass spectrometry.

Calcitonin↗
PubMed1992

[The role of clinical, biochemical and echographic data in identifying the biliary pathogenesis of acute pancreatitis].

The role of clinical (biliary pain and/or jaundice), laboratory (discriminant function (DF) calculated using AST, ALT, AlkPh and GGT serum values) and ultrasonographic (US)(dilation and/or stone of common bile duct (CBD)) findings in identification of the biliary etiology of acute pancreatitis (AP) was studied in 60 patients. AP biliary etiology was defined by ERCP executed in the early phase of the disease (lithiasis and/or stenosis of CBD; endoscopic features of forced papilla in patients with gallstone). US showed the best values of sensitivity (84.6%) and diagnostic efficacy (76.7%); DF showed the best results of specificity (62.5%) and of test positive predictive value (92.8%). The statistical evaluation (McNemar test) showed a significant increase of sensitivity for US vs clinical findings and of specificity for DS vs clinical findings (p less than 0.05). The sensitivity, specificity, accuracy, test negative and positive predictive value were improved to 96.1, 87.5, 96.6, 77.1 and 92% by the combination of US and DF. Therefore the association of US and DF can provide the best non invasive method in rapidly detecting CBD pathology as an etiological factor in AP and then the enough accurate indication to early operative ERCP.

Abdomen↗
PubMed1991

Postheparin plasma diamine oxidase values in the follow up of patients with small bowel Crohn's disease.

Measurement of postheparin plasma diamine oxidase (PHD) activity has been proposed to assess mucosal integrity in several diseases of the small intestine. In Crohn's disease, PHD values identify a group of patients with predominantly small bowel mucosal damage. To determine the role of mucosal involvement in the progression of small bowel Crohn's disease and whether different PHD values can predict different outcomes the changes in PHD values in 41 patients with small bowel Crohn's disease admitted consecutively to our department were investigated. The test was performed during periods of active disease and after either medical or surgical treatment had resulted in improvement. PHD values were significantly lower than in normal subjects (normal range 3.7-7.7 U/ml). In 35 patients with active disease (Crohn's disease activity index (CDAI) greater than 150) two groups were identified by choosing a cut off value of 2 U/ml: 93% of the 15 patients with PHD values lower than 2 U/ml (mean (SD) 1.36 (0.46) U/ml) relapsed at least once in the following year, while only the 20% of the 20 whose values were higher than 2 U/ml (mean (SD) 3.69 (1.50)) relapsed in the same period. The data were statistically significant (Yates's corrected chi 2 = 15.63; p less than 0.0001). The positive and negative predictive values of the test were 93% and 80%, respectively. During relapses, PHD values were consistently lower than previous values, and increased significantly after effective medical or surgical treatment. In the six patients in whom there were no changes in disease activity (CDAI persistently less than 150), there was no change in PHD values. This test may be useful for identifying Crohn's disease patients who are likely to relapse. Furthermore, the data indicate that mucosal damage is common in active small bowel Crohn's disease and improves at least in part after treatment.

Adult↗
PubMed1991

Early endoscopic cholangiopancreatography and sphincterotomy in acute biliary pancreatitis: report of 50 cases.

Endoscopic retrograde cholangiopancreatography (ERCP) was successfully performed in 49/50 consecutive patients with acute pancreatitis and suspected biliary aetiology in the early phases of the disease (24-72 hours from admission). ERCP showed common bile duct lithiasis and/or stenosis (25 cholecystectomized patients) in 41/49 cases (83.7%). In 38 patients endoscopic sphincterotomy (ES) was performed: stone removal was possible in lithiasic patients (36 cases, 13 previously cholecystectomized); 3 further patients showed a main pancreatic duct stenosis (2 of these underwent pancreatic ES). The patients treated with ES showed a quick improvement in symptomatology and clinical outcome; no adverse effect of ERCP was found; no mortality was registered. Comparison with a previous series of 130 cases of acute biliary pancreatitis (ABP) showed a reduction in mortality, complications and length of hospitalization. These findings suggest that, from a diagnostic and therapeutic point of view, early ERCP is safe and useful in ABP.

Acute Disease↗
PubMed1991

[Relapsing polychondritis. A case report with particular cardiac involvement].

Relapsing polychondritis is a rare systemic disease, characterized by recurrent inflammation of articular cartilaginous tissues, with frequent involvement of other organs and systems. While the cause remains unknown, an autoimmune pathogenesis appears likely; the natural history is not completely defined. The authors describe an interesting case with cardiovascular involvement and a good response to cyclosporin A.

Adult↗
PubMed1990

[The clinical, histological and ultrastructural findings in a case of acute steatosis of pregnancy with a severe cholestatic syndrome].

A case of acute steatosis in pregnancy featuring unusually severe cholestasis is discussed with details of the successful outcome for mother and foetus. The correspondence between clinical picture, histological and ultrasound findings is reported together with a detailed review of the latest reports in the literature and what they reveal about the true incidence of the disease, the variability of the clinical picture, whether and when it is better for both mother and child to interrupt.

Acute Disease↗
PubMed1989

Urban helminthiasis in two socioeconomically distinct Costa Rican communities.

A survey on the prevalence of Ascaris lumbricoides, Trichuris trichiura and Hymenolepis nana was conducted in two adjacent, but socioeconomically distinct, urban Costa Rican communities: a squatter settlement and a community with access to modern sewage facilities. The prevalence of these infections was significantly higher in the former. Although squatter children (1-14 years old) were more heavily infected with A. lumbricoides and H. nana than squatter adults, the same pattern was not observed for T. trichiura. The results suggest that local community-based helminthic parasite surveys may more accurately portray the actual health status of socioeconomically diverse urban populations.

Adolescent↗
PubMed1985

Semisynthetic beta-lactam antibiotics. VI. Synthesis and antimicrobial activity of alpha-hydrazonobenzylcephalosporins.

Using as a model cephalosporins with an alpha-hydroxyimino moiety in the side chain, some new (E)-alpha-hydrazono and alpha-methylhydrazono benzyl cephalosporins were prepared. While the synthesis of methylhydrazono-derivatives (I a-d) involved direct condensation of the methylhydrazionacid (II a-b) with a protected 7-aminocephalosporanic derivative, the N-unsubstituted compounds (I e-f) had to be prepared from the N-acyl protected hydrazono acids (III a-d). The cephalosporin (I f) was also obtained as Z-isomer by condensation of the corresponding alpha-oxo compound with 4-nitrobenzyloxycarbonylhydrazine, chromatographic separation of the obtained E-Z mixture, and hydrogenolysis of the Z form. The in vitro antibacterial evaluation showed that N-methyl substitution is favorable among the E compounds, whereas among the N-unsubstituted hydrazono derivatives, the compound Z-(I f), although less stable, is much more potent than the corresponding E-isomer.

Bacteria↗
PubMed1984

High-performance liquid chromatographic separation of cadralazine from its potential metabolites and degradation products. Quantitation of the drug in human plasma and urine.

The chromatographic behaviour of cadralazine and its potential metabolites and degradation products with respect to pH, buffer molarity and composition of eluent is described. A selective method with an adequate sensitivity for the determination of the drug in human plasma and urine is also reported. The method includes extraction of biological fluids with chloroform and the analysis of extracts on a reversed-phase column with isocratic elution and detection at 254 nm. The method has been applied to the analysis of plasma and urine of a patient administered a single oral dose of 30 mg of cadralazine.

Antihypertensive Agents↗
PubMed1984

Degradative behavior of cadralazine in aqueous solution.

The degradation of cadralazine in aqueous solution was investigated in relation to pH, concentration, and temperature, under aerobic and anaerobic conditions in light and dark. The appearance of three main degradation products was also studied. Drug disappearance was dependent on temperature, pH, concentration, and oxygen and followed three different mechanistic pathways: thermal, hydrolytic, and oxidative. The individual rate constants were determined by nonlinear regression fitting.

Air↗
PubMed1982

[Effect of high-frequency percutaneous stimulation on experimental pain].

Ten healthy volunteers were submitted to an experimental pain test performed by electrical stimulation of one tooth, before and after 20 min high-frequency (300 Hz) electrical stimulation, for the purpose of relieving pain, delivered to the lip or to three other somatotopically non related areas. The stimulation of the lip only showed a statistically significant analgesic action. The effect was remarkable (31% of total pain relief) and of the same order of magnitude at any intensity level of the tooth stimulation, the threshold being affected too. It is concluded that a central inhibitory mechanism, activated by large afferents input, should subserve this kind of analgetic procedure.

Adult↗