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Biomedical subjects

A Muzzi

Publications and source records attributed to A Muzzi.

At least 19 recordsLinked to original sources
PubMed2002

Gene expression profile in Neisseria meningitidis and Neisseria lactamica upon host-cell contact: from basic research to vaccine development.

Differential gene regulation in the human pathogen Neisseria meningitidis group B (MenB) and in Neisseria lactamica, a human commensal species, was studied by whole genome microarray after bacterial interaction with epithelial cells. Host-cell contact induced changes in the expression of 347 and 285 genes in MenB and N. lactamica, respectively. Of these, only 167 were common to MenB and N. lactamica, suggesting that a different subset of genes is activated by pathogens and commensals. Change in gene expression was stable over time in N. lactamica, but short-lived in MenB. A large part (greater than 30%) of the regulated genes encoded proteins with unknown function. Among the known genes, those coding for pili, capsule, protein synthesis, nucleotide synthesis, cell wall metabolism, ATP synthesis, and protein folding were down-regulated in MenB. Transporters for iron, chloride and sulfate, some known virulence factors, GAPDH and the entire pathway of selenocysteine biosynthesis were upregulated. Gene expression profiling indicates that approximately 40% of the regulated genes encode putative surface-associated proteins, suggesting that upon cell contact Neisseria undergoes substantial surface remodeling. This was confirmed by FACS analysis of adhering bacteria using mouse sera against a subset of recombinant proteins. Finally, a few surface-located, adhesion-activated antigens were capable of inducing bactericidal antibodies, indicating that microarray technology can be exploited for the identification of new vaccine candidates.

Bacterial Adhesion↗
PubMed2000

Time-resolved experiments on light diffusion in anisotropic random media

Multiple light scattering in isotropic and anisotropic media is studied experimentally with an optical gating technique, as commonly used in fluorescence spectroscopy. The experimental setup permits an accurate analysis of the propagation of a short light pulse through disordered or partially ordered media. The diffusion constant of some isotropic systems is reported, and the anisotropy in the diffusion constant for light diffusion through liquid crystals is observed. For the time-resolved data, good agreement with diffusion theory is found in all cases, including the liquid crystal in the nematic phase.

Journal Article↗
PubMed1999

Long-term effects of carvedilol in idiopathic dilated cardiomyopathy with persistent left ventricular dysfunction despite chronic metoprolol. The Heart-Muscle Disease Study Group.

OBJECTIVES: The purpose of this study was to analyze whether long-term treatment with the nonselective beta-adrenergic blocking agent carvedilol may have beneficial effects in patients with dilated cardiomyopathy (DCM), who are poor responders in terms of left ventricular (LV) function and exercise tolerance to chronic treatment with the selective beta-blocker metoprolol. BACKGROUND: Although metoprolol has been proven to be beneficial in the majority of patients with heart failure, a subset of the remaining patients shows long-term survival without satisfactory clinical improvement. METHODS: Thirty consecutive DCM patients with persistent LV dysfunction (ejection fraction < or =40%) and reduced exercise tolerance (peak oxygen consumption <25 ml/kg/min) despite chronic (>1 year) tailored treatment with metoprolol and angiotensin-converting enzyme inhibitors were enrolled in a 12-month, open-label, parallel trial and were randomized either to continue on metoprolol (n = 16, mean dosage 142+/-44 mg/day) or to cross over to maximum tolerated dosage of carvedilol (n = 14, mean dosage 74+/-23 mg/day). RESULTS: At 12 months, patients on carvedilol, compared with those continuing on metoprolol, showed a decrease in LV dimensions (end-diastolic volume -8+/-7 vs. +7+/-6 ml/m2, p = 0.053; end-systolic volume -7+/-5 vs. +6+/-4 ml/m2, p = 0.047), an improvement in LV ejection fraction (+7+/-3% vs. -1+/-2%, p = 0.045), a reduction in ventricular ectopic beats (-12+/-9 vs. +62+/-50 n/h, p = 0.05) and couplets (-0.5+/-0.4 vs. +1.5+/-0.6 n/h, p = 0.048), no significant benefit on symptoms and quality of life and a negative effect on peak oxygen consumption (-0.6+/-0.6 vs. +1.3+/-0.5 ml/kg/min, p = 0.03). CONCLUSIONS: In DCM patients who were poor responders to chronic metoprolol, carvedilol treatment was associated with favorable effects on LV systolic function and remodeling as well as on ventricular arrhythmias, whereas it had a negative effect on peak oxygen consumption.

Adrenergic beta-Antagonists↗
PubMed1979

Protection from natural infection after live influenza virus immunization in an open population.

Live attenuated influenza vaccine containing the recombinant of A/Victoria/3/75 with A/PR/8/34 virus was administered to healthy adults in a field trial aimed at evaluating protection provided by immunization. The study was designed to measure the effect of vaccination on absenteeism from respiratory disease during a natural influenza epidemic. A total of 2115 male employees of the public transport service of Rome volunteered to participate in the trial, 1050 and 1065 receiving vaccine and placebo respectively, in a randomized blind fashion. Vaccination procedure was completed by the end of December 1976. A small-sized outbreak of influenza, due to a viral strain antigenically homologous to the vaccine, occurred during the month of February 1977. Analysis of absenteeism data, classified according to medical certificate, indicated that morbidity from respiratory disease was reduced in vaccinees compared with controls during the epidemic month; the rate of increase of morbidity compared with that of the preceding month was then three times lower in vaccinees than in controls and the difference in absenteeism between the two groups greatly exceeded the ordinary fluctuation that was observed during non-epidemic periods.

Adult↗
PubMed1978

Excess mortality from influenza in a large urban population, Rome, Italy, 1956--76.

Influenza activity was studied in the Rome population from 1956 to 1976 by analysis of mortality from respiratory causes and from all causes. During cold weather months, type A influenza virus was associated, as a rule, with epidemic excess deaths at two year intervals while type B virus was prevalent twice during isolation data were also compared with epidemic excess mortality during four consecutive years. The evidence obtained indicated that influenza virus isolation alone does not represent a reliable index of epidemic influenza activity in this population. The proportion of deaths attributed to respiratory causes consistently increased in every epidemic, the most pronounced increases occurring during large epidemics. The break-down by age of deaths from respiratory causes in the course of two epidemic periods showed that the percentage distribution of deaths was essentially the same as in non-epidemic periods. This evidence indicates that the same factors influencing the age-related distribution of mortality from respiratory causes during non-epidemic periods, probably affect the fatal outcome of influenza during epidemics.

Absenteeism↗
PubMed1976

[Complement fixation, hemagglutination inhibition and neuraminidase inhibition reactions in the seroepidemiologic evaluation of an influenza A epidemic].

Complement-fixing (CF), hemagglutination-inhibiting (HI) and neuraminidase-inhibiting (NI) antibodies in respect of type A influenza virus were titrated on 2080 serum specimens. The sera were collected between December 1974 and May 1975 for the open population of Rome, in groups of an average of 300 samples per month. Influenza type A strains, related to the Port Chalmers variant, were isolated in Rome in January and February 1975, during that time a significant increase of antibody titers and of serum positivity was detected. The increase of positive response for influenza type A antigen was of 21%, 17% and 8% for FC, HI and NI reactions, respectively. The NI reaction proved to be less responsive that the CF and HI reactions for the purposes of sero-epidemiological evaluation of the influenza epidemic.

Antibody Formation↗
PubMed1975

Longitudinal epidemiological survey on hepatitis B-antigen carriers among institutionalized juvenile diabetics.

An epidemiological study was carried out in a juvenile diabetics institution, in order to determine the incidence and the significance of the hepatitis associated Australia antigen (HBAg) carriers. By means of counterelectrophoresis and CF an average of 15% HBAg-positive individuals was found during the course of the search (June 1970-January 1973). As a rule the carrier state appeared to be longlasting and it was only occasionally associated with symptoms and/or signs of liver involvement. Isolation measures to inhibit spread of serum hepatitis (the hepatitis most associated with HBAg) failed partially to prevent the spread of the HBAg associated agent suggesting that nonparenteral transmission could play a role in the diffusion of the infection.

Adolescent↗
PubMed1974

Epidemiological evaluation of influenza in Italy.

A statistical study of the mortality from all causes and from respiratory diseases was carried out in an evaluation of the influenza epidemics in Italy from 1956 to 1973. Type A influenzaviruses were responsible for outbreaks every 2-3 years. Type B influenzavirus appeared every 4 years and accounted for a single noteworthy epidemic in 1962-63. From the analysis of data on both general mortality and respiratory mortality a better evaluation of the extent of the influenza outbreaks could be made.

Disease Outbreaks↗