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Biomedical subjects

A Mele

Publications and source records attributed to A Mele.

At least 127 records · Page 7Linked to original sources
PubMed1995

Replacing the glutamate ligand in the structural zinc site of Sulfolobus solfataricus alcohol dehydrogenase with a cysteine decreases thermostability.

The alcohol dehydrogenase gene from the thermophilic archaeum Sulfolobus solfataricus has been subcloned and expressed in Escherichia coli under the control of the T7 inducible promoter. The recombinant protein shows properties analogous to those of the native enzyme, including thermostability, despite the fact that E.coli does not post-translationally modify two lysine residues which are N-epsilon-methylated in the native enzyme. We constructed a 3-D model of the S.solfataricus alcohol dehydrogenase using the known structure of its isozyme from horse liver as a template. Our analysis of the structural zinc binding site suggested that this site is present and functional in the S.solfataricus enzyme and that a glutamate ligand can contribute to thermostability by influencing electrostatic interactions around the metal centre. To investigate this hypothesis, we constructed, expressed and characterized a mutant where the glutamate is replaced by a cysteine, thus restoring the zinc binding site of mesophilic alcohol dehydrogenases. The mutant shows the same activity but a reduced thermostability with respect to the wild-type recombinant protein, as suggested by our model.

Alcohol Dehydrogenase↗
PubMed1995

Prognostic value of anesthesia type for patients treated for cutaneous melanoma.

BACKGROUND: General anesthesia has been reported to compromise several cell-mediated immune functions. Hence it is plausible that anesthesia could affect the postoperative outcome of cancer patients. OBJECTIVE: To study the influence of the type of anesthesia on survival of 459 patients with localized cutaneous melanoma observed between 1980 and 1991. METHODS: Crude survival proportions were calculated by the methods of Kaplan and Meier. Cox proportional hazards regression analysis was used to estimate the effect on death rates of the type of anesthesia. RESULTS: The 5-year survival proportions were 81% for patients treated under local anesthesia, 71.9% for patients receiving halothane isoflurane or enflurane, and 88.4% for neuroleptanalgesia (P < .05). After multiple adjustment for other prognostic variables (tumor thickness, presence of ulceration, age, sex, cross-sectional profile), using patients treated under local anesthesia as a reference group, the relative risk for general anesthesia with volatile agents was 1.3 (95% CI, 0.84-2.10). CONCLUSION: The type of anesthesia does not seem to affect the survival of patients with cutaneous melanoma, when other prognostic factors are considered.

Adolescent↗
PubMed1995

Beauty treatments and risk of parenterally transmitted hepatitis: results from the hepatitis surveillance system in Italy.

The role of ear-piercing, tattooing, attendance at chiropodist or manicurist and barber shop shaving in transmitting hepatitis B and hepatitis non-A, non-B was evaluated. Data reported here were collected from 1985 to 1993 by the National Viral Hepatitis Surveillance System. The association between parenterally transmitted hepatitis and the considered risk factors was estimated, comparing 6,395 hepatitis B and 2,558 hepatitis non-A, non-B cases with 4,789 hepatitis A cases, using the case-control method. Of the non-A, non-B cases tested from 1991 to 1993, 56.6% were anti-HCV positive. The incidence of parenterally transmitted hepatitis cases reporting specific beauty treatments was also evaluated. Tattooing, ear-piercing and barber shop shaving were associated with both parenterally transmitted hepatitides, while attendance at a chiropodist or manicurist was associated only with hepatitis B. During the study period the incidence of acute hepatitis B and non-A, non-B cases reporting beauty treatments declined by 49%. In spite of this decline, considering that a large part of the general population is exposed to the considered risk factors, the role of beauty treatments in transmitting hepatitis B and hepatitis non-A, non-B should not be underestimated.

Adolescent↗
PubMed1995

Hospitalization rate and mean days of hospitalization of notified viral hepatitis cases in Italy. The Seieva Collaborating Group.

The hospitalization rate and the mean days of hospitalization of notified viral hepatitis cases in Italy were estimated by a specific surveillance system for acute viral hepatitis over the period 1987-1992. The hospitalization rate was very high, ranging from 88.8% for hepatitis A to 90.9% for non-A, non-B hepatitis. No changes were observed over time. For each type of hepatitis the highest figure was observed in the 15-24 year age group. The mean days of hospitalization of hepatitis B (24.2) and non-A, non-B (20.5) hepatitis was significantly higher (p < 0.05) than that of hepatitis A (16.5). The highest mean days of hospitalization of hepatitis A and B occurred in the 0-14 year age group, while for non-A, non-B hepatitis it was observed in subjects over 24 years of age. These findings indicate a nearly similar rate of hospitalization of all types of hepatitis. Hepatitis B and non-A, non-B hepatitis show a more prolonged course than hepatitis A.

Adolescent↗
PubMed1995

Low prevalence of anti-HCV antibodies among Italian Air Force recruits.

In 1990, the prevalence of antibodies to hepatitis C virus (anti-HCV) was assessed among 4,978 Air Force recruits aged 18-26 years coming from all regions of Italy. Positivity to anti-HCV was found by both IIIrd generation EIA and RIBA in 24 (0.48%) study participants. The prevalence was twice as high in Southern Italy and the islands as in Northern and Central Italy (0.76% vs. 0.35%), a difference which was not statistically significant. The results of multiple logistic regression showed that no sociodemographic variable (region of birth, father's years of education, number of siblings) was associated with anti-HCV positivity. No anti-HCV-positive individual was positive for HBsAg. Anti-HCV positivity was found in 0.8% (2/236) of the participants who were positive for anti-HBc and in 0.5% (22/4742) of those who were anti-HBc negative, also a difference which was not statistically significant. Thus no association was found between HCV and HBV infections. These findings indicate that in Italy, HCV infection is an uncommon event among young adult males.

Adolescent↗
PubMed1995

Case control study of risk factors for hepatitis A: Naples 1990-1991. Hepatitis Collaborating Group.

An increased incidence of hepatitis A was observed in Naples from 1990-1991. A hospital-based case-control study was carried out to evaluate the relative importance of various risk factors. A hundred and ninety-eight cases and 238 hospital controls were recruited during the study period. The strongest association was contact with a jaundiced person among children. A correlation was also shown for children and adults with raw shellfish consumption and pre-school nursery attendance or presence in the household of children attending pre-school nurseries. History of travel and intravenous drug use were risk factors for adult subjects. Considering the relative importance of the specific risk factors we found that 38% of the acute hepatitis A cases were attributable to contact with a jaundiced person, 15% to presence in the household of children attending pre-school nurseries and 28% to raw shellfish consumption.

Acute Disease↗
PubMed1995

[Epidemiology and prevention of HCV infection in dialysis centers].

From many epidemiological studies comes out that haemodialysis patients are at high risk of hepatitis C virus (HCV) infection. This review shows the results of several prevalence and incidence studies carried out in dialysis centres. The prevalence of anti-HCV antibodies in haemodialysis patients varies from 20% to 38%. From these surveys comes out that serodiagnostic tests, usually employed in laboratory diagnosis (ELISA and RIBA), may underestimate the true prevalence of HCV infection. The very important risk factors in the haemodialysis units are blood transfusion and the length of time on haemodialysis. Nevertheless, these are not sufficient to explain completely the high prevalence of subjects HCV positive among the dialysis patients. Contamination of environmental surfaces, caused by a non correct application of the asepsis and disinfection techniques, could be, according to several authors, the more important cause of this infection among the dialysis patients.

Hepatitis C↗
PubMed1995

A nuclear magnetic resonance method for the determination of the purity of commercial dequalinium chloride.

4-amino-1-(10-4'-quinaldinylaminodecyl)quinaldinium chloride (3) has been identified through nuclear magnetic resonance (NMR) studies as one of the impurities of a commercial sample of dequalinium chloride (CAS 522-51-0). The NMR technique is proposed as a rapid method for the recognition and quantification of the impurities in dequalinium chloride samples.

Chromatography, High Pressure Liquid↗
PubMed1994

Hair dye use and other risk factors for leukemia and pre-leukemia: a case-control study. Italian Leukemia Study Group.

A case-control study was carried out to examine the relation of three subtypes of leukemia cells and refractory anemia with excess of blasts to selected behavioral and environmental factors. Cases aged 15 years or older were recruited in three hospitals located in Rome, Bologna, and Pavia, respectively. Outpatients who were either normal or had nonneoplastic hematologic disorders and were seen in the same hospitals as the cases were enrolled as controls. Two hundred fifty-two patients with acute myeloid leukemia, 100 with acute lymphocytic leukemia, 111 with refractory anemia with excess of blasts, 156 with chronic myeloid leukemia, and 1,161 controls were included in the study. Refractory anemia with excess of blasts and chronic myeloid leukemia were included because they are regarded as forms of pre-leukemia. Odds ratio estimates were generally imprecise, but associations were suggested between specific case subtypes and exposure to dark hair dye, selected occupations (shoemaker, painter, electrician, child care), residence in houses built with tuff, and smoking. Although the exploratory nature of the study and its limited statistical power preclude firm conclusions, its results are consistent with those of previous studies, and are in general biologically plausible.

Adolescent↗
PubMed1994

Transmission of hepatitis A to patients with hemophilia by factor VIII concentrates treated with organic solvent and detergent to inactivate viruses. The Italian Collaborative Group.

OBJECTIVE: To determine whether an outbreak of hepatitis A virus (HAV) infection that occurred in 52 patients with hemophilia in Italy was acquired through infusion of contaminated factor VIII or through environmental enteric transmission. DESIGN: A case-control study and a molecular analysis of HAV sequences from implicated lots of factor VIII and from infected patients. PATIENTS: The first 29 patients with hemophilia and jaundice in whom hepatitis A developed were compared with one to three matched controls with hemophilia but no jaundice. MEASUREMENTS: Type of concentrate and batches infused, number of doses, contacts with persons who had jaundice or hepatitis A, travel abroad to countries reported to have a high attack rate for hepatitis A, and consumption of raw shellfish. Hepatitis A viral sequences sought by polymerase chain reaction in lots of factor VIII and in serial serum samples from two patients with hemophilia in whom hepatitis A developed. Amplification by polymerase chain reaction of cDNA transcribed with reverse transcriptase from matched sets of factor VIII and recipient serum samples. Determination of nucleotide sequence of amplified hepatitis A virus genome. MAIN RESULTS: Case patients were neither more nor less likely than controls to have traveled to high-risk countries, consumed raw shellfish, or had contact with persons with jaundice. Case patients were more likely than controls to have received a factor VIII concentrate treated with a solvent-detergent mixture to inactivate viruses (odds ratio, infinity; 95% CI, 4.5 to infinity) and to have had larger infusions of the concentrate during the presumed HAV incubation period (odds ratio, 8.54; CI, 2.78 to 27.5). Hepatitis A viral sequences were found in 5 of 12 tested lots of factor VIII. Genomic sequences of HAV obtained for two matched sets of factor VIII and recipient serum samples were identical within each set but different for the two sets. CONCLUSION: Hepatitis A was transmitted by a factor VIII concentrate treated by a virucidal method (solvent-detergent) that ineffectively inactivates nonenveloped viruses.

Adolescent↗
PubMed1994

Survival and prognostic factors in patients with localised cutaneous melanoma observed between 1980 and 1991 at the Istituto Dermopatico dell'Immacolata in Rome, Italy.

530 patients with localised cutaneous melanoma consecutively observed between 1980 and 1991 at a hospital for skin diseases in Rome, Italy, were studied. Crude survival proportions were calculated with the method of Kaplan and Meier. Cox proportional hazards regression analysis was used to estimate the effect of prognostic factors on death rates. Females and younger patients had better 5- and 10-year survival rates, while increasing tumour thickness was associated with a decrease in survival time. In the multivariate analysis, an independent association with survival was found for tumour thickness, presence of ulceration, age, sex and cross-sectional profile of neoplasia. Our study confirms that females and young patients with thin melanomas have a better prognosis, while the importance of cross-sectional profile needs further study.

Adolescent↗
PubMed1994

Hepatitis B in health workers in Italy.

In Italy, a vaccination campaign against hepatitis B was launched in 1985. It was strongly recommended for health care workers. Over the period 1986-91 the incidence rate of acute B hepatitis in the general population declined from 12/100,000 in 1986 to 5/100,000 in 1991. The corresponding figures among hospital workers were 42.5/100,000 (RR 3.5; 95% CI 2.55-4.92) in 1986 and 14.5/100,000 (RR 2.9; 95% CI 2.03-4.14) in 1991, respectively. The proportion of HBV cases with jaundice was about the same in the general population (77.6%) and in the health care staff (74.2%). Nearly 6% of hospital workers cases had completed the schedule of HBV vaccine. Despite the fact that vaccination against HBV has been strongly recommended for hospital workers, the incidence of infection in this job category has continued to be higher than that in the general population, probably as a consequence of poor vaccine coverage. These findings reiterate the need for aggressive vaccination programmes in hospital workers.

Health Personnel↗
PubMed1994

Incidence and risk factors of acute Delta hepatitis in Italy: results from a national surveillance system. SEIEVA Collaborating Group.

The incidence of hepatitis Delta virus in the general Italian population was estimated by a specific surveillance system for acute viral hepatitis over the period 1987-1992. The hepatitis Delta virus incidence rate declined from 3.1/1,000,000 inhabitants in 1987 to 1.2/1,000,000 in 1992. Males predominated (83.8% of cases); the sex ratio was 5.2. Only 2.5% of cases occurred in subjects younger than 15 years. There were 119 (49.4%) coinfections of Delta and B hepatitis and 122 (50.6%) Delta superinfections in chronic HBsAg carriers. Jaundice was present in 83.6% of cases. The hospitalization rate was 97.5%; median stay in hospital was 25 days (range 1-98 days). The results of multivariate analysis showed that a history of intravenous drug abuse (odds ratio 34.9; confidence interval 95% = 16.8-72.5), household contact with an HBsAg+ carrier (odds ratio 10.7; confidence interval 95% = 4.36-23.30) and a history of two or more sexual partners within the previous 6 months (odds ratio 2.44; confidence interval 95% = 1.34-4.43) were independent risk factors associated with Delta hepatitis. No association was found with the other risk factors considered, such as blood transfusion, surgical intervention, hospitalization, other percutaneous exposures, dental therapy, contact with an icteric case, and household contact with an i.v. drug abuser. These findings indicate that, in Italy, Delta hepatitis currently has a minor impact. In addition to intravenous drug abuse and household contact with an HBsAg+ carrier, heterosexual activity appears to be an efficient route of HDV transmission.

Acute Disease↗
PubMed1994

Synthesis, absolute configuration, conformational analysis and binding affinity properties of enantiomeric forms of DAU 5750, a novel M1-M3 muscarinic receptor antagonist.

Both the enantiomeric forms of DAU 5750, a novel muscarinic receptor antagonist, have been synthesized in order to assess the relevance of configurational/conformational features for high affinity binding to muscarinic receptor subtypes. The attribution of absolute stereochemistry and conformational analysis by means of molecular modelling and NMR techniques are also reported.

Chymotrypsin↗
PubMed1994

Reversal of chlorpromazine-induced avoidance depression by the N-methyl-D-aspartate antagonist, dizocilpine, in mice.

The non-competitive N-methyl-D-aspartate (NMDA) antagonist MK-801 (dizocilpine) was tested, alone or in combination with chlorpromazine, in mice previously trained in the shuttlebox. The lowest doses of dizocilpine (0.02 and 0.04 mg kg-1) attenuated the disrupting action of the neuroleptic (1.5 mg kg-1) on avoidance-performance, while avoidance depression induced by 1.5 and 2 mg kg-1 chlorpromazine was completely or almost completely reversed by 0.08 mg kg-1 NMDA antagonist. The highest dose (0.16 mg kg-1) of dizocilpine did not ameliorate avoidance-performance of mice receiving 2 mg kg-1 chlorpromazine, perhaps because of ataxic effects produced by the drug combination, at these doses. The results support suggestions for a potential use of NMDA antagonists in the treatment of extrapyramidal side-effects of neuroleptics.

Animals↗
PubMed1994

Risk factors for acute non-A, non-B hepatitis and their relationship to antibodies for hepatitis C virus: a case-control study.

A case-control study was carried out comparing 333 case subjects with non-A, non-B hepatitis and 1095 hospital control subjects. Of 333 case subjects, 197 (59%) were positive for hepatitis C antibody (anti-HCV). Excluding blood transfusion and intravenous drug use, surgical intervention and dental therapy were strongly associated with anti-HCV-positive cases: in particular, obstetric and gynecology surgical intervention was found to be strongly associated with HCV positivity (odds ratio [OR] = 32; 95% confidence interval [CI] = 7, 147). Raw shellfish consumption was a risk factor for anti-HCV-negative cases (OR = 2.2; 95% CI = 1.0, 5.1), thus suggesting an enterically transmitted virus in sporadic non-A, non-B hepatitis in Italy.

Acute Disease↗