Search PubMed⌕ Search

Biomedical subjects

C Chezzi

Publications and source records attributed to C Chezzi.

34 records · Page 2Linked to original sources
PubMed1990

Inhibition of the uncoating of bovine enterovirus by short chain fatty acids.

Short chain fatty acids inhibit the replication of bovine enterovirus but are almost ineffective against poliovirus type 1, coxsackievirus B5, encephalomyocarditis virus and human rhinovirus 1B. Lauric acid binds to bovine enterovirus, thereby stabilizing the virus particle to heat degradation. Fatty acid-bound virions attach to susceptible cells but fail to undergo cell-mediated uncoating. The inhibitory effect is reversible with chloroform and may result from a hydrophobic interaction between the fatty acid and a specific site on the virus particle.

Animals↗
PubMed1989

Biotyping of bacterial isolates using the yeast killer system.

Forty-four presumptive killer yeasts were tested against bacterial isolates, including rapid-growing gram-positive and gram-negative bacteria, as well as slow-growing bacteria, such as the mycobacteria. A killer system, based on the patterns of bacterial susceptibility to the action of nine selected killer yeasts, was developed for epidemiological purposes. The killer system, previously standardized for yeasts and hyphomycetes, was adapted to the specific growth conditions of the bacterial isolates. The results obtained confirm that susceptibility to the yeast killer phenomenon is widespread among microorganisms unrelated to yeasts and that it could form the basis for a convenient and adaptable biotyping method in microbiological laboratories.

Bacterial Typing Techniques↗
PubMed1989

Evaluation of Western immunoblotting technique in the serological diagnosis of human syphilitic infections.

Purified human syphilitic antibodies against both 15.5 Kd and 45 Kd treponemal antigens appear T. pallidum specific and do not cross react with antigens possessed by other treponemes (T. phagedenis, T. hyodysenteriae and a human intestinal treponeme). By using Western immunoblotting technique, 107 out of 110 syphilitic patients and 291 out of 294 subjects with serologically positive diagnostic tests for syphilis were found to have in their sera antibodies against a 15.5 Kd specific antigen of T. pallidum. These antibodies were present in 100% of the patient with secondary or early latent syphilis, both untreated and treated, in 98.24% of those with late latent treated syphilis and in 100% of patients with neurosyphilis. On the contrary, they were absent in 47 patients with false positive reactions for syphilis and in 121 healthy blood donors. For these reasons, the demonstration of these kind of antibodies in a patient's serum can be considered of high value in differentiating syphilitic patients from non infected individuals.

Antibodies, Bacterial↗
PubMed1989

Serological study of yeast killer toxins by monoclonal antibodies.

Yeast killer toxins coded by determined and undetermined killer plasmids or presumptive nuclear gene(s) in various genera (Saccharomyces, Kluyveromyces, Pichia and Candida) have been serologically investigated by a monoclonal antibody (KT4), produced against the yeast killer toxin of Pichia (Hansenula) anomala UCSC 25F. Double immunodiffusion with the killer toxins as antigens and indirect immunofluorescence on whole cells of the corresponding killer yeast have been used. In both the serological procedures, monoclonal antibody KT4 proved to be reacting only with the killer toxins and the whole cells of yeasts belonging to the genus Pichia.

Antibodies, Monoclonal↗
PubMed1989

In-vitro activity of meropenem against clinical isolates in a multicentre study in Italy.

A multicentre in-vitro study was undertaken to evaluate the susceptibility of bacterial pathogens isolated in different Italian hospitals to meropenem. A total of 1399 aerobic and 452 anaerobic strains was analysed. Comparative agents were imipenem, cefotaxime, ceftazidime, ceftriaxone, piperacillin, ciprofloxacin, gentamicin, amikacin, plus vancomycin when appropriate. The MIC ranges (mg/l) of meropenem were: 0.015-2 for Klebsiella spp., Proteus spp., Morganella morganii and Providencia spp.; less than 0.008-1 for Escherichia coli; 0.016-32 for Serratia spp.; 0.03-2 for Enterobacter spp. and Citrobacter spp.; 0.03- greater than 128 for Acinetobacter anitratus; 0.03-32 for Pseudomonas spp.; less than 0.008-0.5 for Haemophilus spp. and Neisseria spp.; 0.015-64 for Staphylococcus spp.; 0.06- greater than 128 for Enterococcus spp.; less than 0.008-0.25 for Streptococcus spp.; 0.016-8 for Fusobacterium spp.; 0.03-8 for Bacteroides spp.; less than 0.06-0.5 for anaerobic Gram-positive cocci; 0.08-2 for Clostridium spp. Meropenem exhibited superior antibacterial activity against the aerobic and anaerobic strains tested when compared to the other beta-lactam drugs. The new carbapenem was as active as ciprofloxacin and more active than imipenem and the aminoglycosides against Enterobacteriaceae and Ps. aeruginosa. It was also more active than ciprofloxacin against most strains of Gram-positive cocci. Meropenem was slightly less potent than imipenem against staphylococci and enterococci, with the exception of oxacillin-susceptible Staph. aureus against which meropenem and imipenem exhibited similar antibacterial activity.

Aminoglycosides↗
PubMed1985

Epidemiological survey on bacterial, viral and parasitic agents in patients affected by acute enteritis.

During the period June 1983-May 1984, faecal specimens from 797 patients with acute enteritis were examined for the presence of bacterial, viral and parasitic agents; 209 (26.2%) enteritic pathogens were identified, of whom 118 (35.4%) in 333 samples from the pediatrics wards. Bacterial agents were detected in 122 (15.3%), viruses in 63 (7.9%) and parasites in 25 (3.1%) of the 797 specimens. LT-producing E. coli, Salmonella and Rotavirus were the most frequent pathogens. Bacterial agents occurred most frequently in the summer and autumnal months, whereas viruses showed two peaks, the first one in summer due to cultivable agents, the second in winter to Rotavirus mainly.

Acute Disease↗
PubMed1985

Biological characterization of FPV, Ulster 73, replicative cycle.

The replication of an avian influenza A, Fowl plague virus (FPV), Ulster 73 strain, was studied in chick embryo fibroblasts, assumed to be the natural host, and in cells of different origin such as LLC-MK2, Hep-2, Vero, KB and Mc Coy. In the natural host, FPV shows a characteristic pattern of polypeptide synthesis suggesting a transcriptional and/or translational mediated control mechanism, specific for this strain of influenza A. FPV was able to give a productive infection in all the above mentioned cells releasing mature viral particles. This behaviour is very interesting if one compares FPV, Ulster strain to FPV, Rostock strain. These viruses, belonging to the same antigenic subtype (H7 N1 group) recognize the same cellular determinants but Rostock strain undergoes an abortive replication whereas Ulster strain gives productive infection in all cellular lines tested. These observations lead to postulate a viral genetic mechanism controlling host range both at early and late steps in infection. This genetic mechanism controls the interaction between viral and cell molecules affecting synthesis of virus specific polypeptides.

Animals↗
PubMed1976

Simultaneous detection of reverse transcriptase and high molecular weight RNA in tissue of patients with Hodgkin's disease and patients with leukemia.

Complexes of high-molecular-weight RNA and reverse transcriptase (RNA-dependent DNA nucleotidyltransferase) have been detected in 14(77.8%) of 18 spleen from patients with Hodgkin's disease and in all samples tested of peripheral leukocytes and spleens from leukemic patients. The enzyme and its template are localized in a particle having a density between 1.16 and 1.19 g/ml. These observations describe characteristic features of RNA tumor viruses.

Hodgkin Disease↗
PubMedDate not supplied

Inhibition of late influenza virus genome expression by diamidinophenylindole.

The growth cycle of influenza virus strain FPV, Ulster 73, was altered by treatment of LLC-MK2 cells with diamidinophenylindole. Viral protein synthesis was restricted to the early pattern of virus multiplication, and post-treatment experiments showed the ability of the drug to block virus replication until the 4th hour p.i. Drug addition (followed by removal) revealed the inhibition of synthesis of late viral products, and especially of membrane protein. Kinetic studies on the production of viral RNA indicated a decrease in the synthesis of late virus-induced RNA species, suggesting that the target of DAPI is probably the late transcription of the virus genome. The nonpermissive condition mediated by the drug could represent a suitable model to study cellular intervention during viral growth.

Capsid↗
PubMedDate not supplied

Role of acylation of viral haemagglutinin during the influenza virus infectious cycle.

We investigated fatty acid residues bound to the haemagglutinin (HA) of type A influenza viruses by growing the viruses in permissive chick embryo fibroblasts (CEF) and in non-permissive HeLa-229 cells using a maintenance medium containing 3H-palmitic acid. Our results suggest that fatty acid acylation of the major viral glycoprotein may be an important prerequisite for the production of mature viral particles. Indeed, palmitoylation is found in infected CEF, but is completely lacking in non-permissive HeLa-229 cells infected by the same virus strains. We conclude that this type of post-translational modification of virus HA glycoprotein could be a general phenomenon regulating the maturation and budding of influenza virus.

Acylation↗