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Biomedical subjects

P Tomao

Publications and source records attributed to P Tomao.

16 recordsLinked to original sources
PubMed2005

Prevalence and incidence of antibodies to Borrelia burgdorferi and to tick-borne encephalitis virus in agricultural and forestry workers from Tuscany, Italy.

The ticks Ixodes persulcatus and Ixodes ricinus are the main vectors of both Borrelia burgdorferi sensu lato and tick-borne encephalitis (TBE) virus in Eurasia. Borrelia burgdorferi is the cause of Lyme borreliosis, and TBE is a biphasic meningoencephalitis induced by an arbovirus belonging to the flavivirus family. The principal aims of the current investigation were (i) to determine the frequency of serological evidence of Borrelia burgdorferi sensu lato and TBE infections in healthy agricultural and forestry workers, (ii) to determine the incidence of seroconversion for antibodies against Borrelia burgdorferi sensu lato and TBE virus in Tuscan workers during a 1-year survey; and (iii) to assess the occupational risk for agricultural and forestry activities in a defined area (Tuscany, Italy). A total of 412 blood samples were taken from agricultural and forestry workers, and information on age, duration of employment, and history of tick bites was collected in a questionnaire to establish the risk factors for the diseases. Three hundred sixty-five blood donors from the same region served as controls. To estimate the rate of seroconversion, 176 of the agricultural and forestry workers were tested 1 year later. IgG and IgM antibodies against Borrelia burgdorferi sensu lato and TBE virus were detected in serum by an enzyme-linked immunosorbent assay and confirmed by Western blot analysis for Borrelia burgdorferi and by a test for inhibition of hemagglutination for TBE. Antibodies against Borrelia burgdorferi were more frequent among the workers than in the control group (7.8% vs. 4.9% in the IgG-IgM enzyme-linked immunosorbent assay and 7.03% vs. 3.56% in the confirmatory test). No seropositivity was observed for TBE virus. Eighteen of 176 subjects who underwent a second blood test developed specific antibodies against Borrelia burgdorferi within 1 year.

Adult↗
PubMed1999

Antiviral effect of hyperthermic treatment in rhinovirus infection.

Human rhinoviruses (HRV) are recognized as the major etiologic agents for the common cold. Starting from the observation that local hyperthermic treatment is beneficial in patients with natural and experimental common colds, we have studied the effect of brief hyperthermic treatment (HT) on HRV replication in HeLa cells. We report that a 20-min HT at 45 degrees C is effective in suppressing HRV multiplication by more than 90% when applied at specific stages of the virus replication cycle. Synthesis of virus proteins is not affected by HT, indicating that the target for treatment is a posttranslational event. The antiviral effect is a transient cell-mediated event and is associated with the synthesis of the 70-kDa heat shock protein hsp70. Unlike poliovirus, rhinovirus infection does not inhibit the expression of hsp70 induced by heat. The possibility that hsp70 could play a role in the control of rhinovirus replication is suggested by the fact that a different class of HSP inducers, the cyclopentenone prostaglandins PGA1 and delta 12-PGJ2, were also effective in inhibiting HRV replication in HeLa cells. Inhibition of hsp70 expression by actinomycin D prevented the antiviral activity of prostaglandins in HRV-infected cells. These results indicate that the beneficial effect of respiratory hyperthermia may be mediated by the induction of a cytoprotective heat shock response in rhinovirus-infected cells.

Antiviral Agents↗
PubMed1996

Inhibition of poliovirus replication by prostaglandins A and J in human cells.

Cyclopentenone prostaglandins (PGs) inhibit the replication of a wide variety of enveloped DNA and RNA viruses. The antiviral activity is associated with alterations in the synthesis, maturation, and intracellular translocation of viral proteins. In the present report, we describe the effects of cyclopentenone PGs PGA1 and delta 12-PGJ2 on poliovirus (PV) replication in HeLa cells. Both PGs were found to inhibit PV replication dose dependently. Virus yield was significantly reduced at nontoxic concentrations, which did not suppress RNA or protein synthesis in uninfected or PV-infected cells. Both the pattern of PV proteins synthesized and the kinetics of viral protein synthesis and degradation appeared to be similar in PGA1-treated cells and control cells. Antiviral PGs have been shown to selectively inhibit virus protein synthesis during the replication of several viruses, including vesicular stomatitis virus (VSV), and this effect has been recently associated with the induction of a 70-kDa heat shock protein (HSP70). PGA1 and delta 12-PGJ2 were found to induce HSP70 synthesis in uninfected or VSV-infected HeLa cells. PV infection was found to inhibit PG-induced HSP70 synthesis in these cells, suggesting that the lack of ability of cyclopentenone PGs to block PV protein synthesis could be related to an impaired heat shock response in PV-infected cells. The finding that PV protein synthesis was not inhibited by PGs suggests that cyclopentenone PGs could interfere with a late event in the virus replication cycle, such as protein assembly and maturation of PV virions.

Antiviral Agents↗
PubMed1995

In vitro activity of commercially manufactured disinfectants against Pseudomonas aeruginosa.

The in vitro activity of 17 commercially manufactured disinfectants routinely used in a large teaching hospital was tested against 128 strains of Pseudomonas aeruginosa isolated from hospitalized patients and the hospital environment. Except for quaternary ammonium salts, all the disinfectants at dilutions higher or equalling those recommended by the manufacturer were adequate to suppress P. aeruginosa. Chlorhexidine-, povidone-iodine- and glutaraldehyde-based disinfectants at dilutions 4 to 8-fold lower than the normal use dilution had a marked bactericidal effect ( > 3 log10 reduction of viable cells) within a short time (10 to 120 min). Similar formulations produced by different manufacturers exhibited comparable activity against P. aeruginosa.

Disinfectants↗
PubMed1995

Effect of chloro-, cyano-, and amidino-substituted flavanoids on enterovirus infection in vitro.

Synthetic flavans, isoflavans and isoflavenes substituted with chloro, cyano and amidino groups were tested for their in vitro activity against poliovirus type 2, Coxsackie virus B4, echovirus type 6 and enterovirus 71. Plaque-reduction assays showed that substituted 3-(2H)-isoflavenes, carrying a double bond in the oxygenated ring, possess antiviral activity higher than that of the corresponding isoflavans. The most effective compounds were 4'-chloro-6-cyanoflavan and 6-chloro-4'-cyanoflavan. Studies on the mechanism of action of these two compounds suggested an effect on the early stages of viral replication.

Amidines↗
PubMed1994

Lack of association between clinical and environmental isolates of Pseudomonas aeruginosa in hospital wards.

Seventy-three environmental and clinical isolates of Pseudomonas aeruginosa recovered from a single hospital over a 6-month period were compared for epidemiological type characteristics. Environmental isolates were obtained from sinks, taps and water, in rooms where patients were treated. The strains represented only six O-antigenic types and 8.2% of them were not typable. Serotype 011 was most frequent in the environment, whereas serotypes 06, 012 and 02,5 predominated among clinical isolates. More than 60% of all isolates belonged to four pyocin types (1, 10, 33 and 45), and approximately 80% were phage typable. Environmental isolates were more sensitive to antibiotics than clinical isolates. There was little correspondence between the types of strains of P. aeruginosa isolated from patients and those isolated from the environment. However, isolates of identical type were frequently recovered from different patients within the same clinic and were found to be related in time and location. We conclude that the environment was not an important source of P. aeruginosa infection and that transfer of organisms was mainly from patient-to-patient.

Bacterial Typing Techniques↗
PubMed1994

Chlamydia trachomatis genitourinary infections: laboratory diagnosis and therapeutic aspects. Evaluation of in vitro and in vivo effectiveness of azithromycin.

Chlamydia trachomatis (C.t.) cell culture represents a sensitive method for the diagnosis of chlamydial infection and the only one which makes it possible to determine the susceptibility of an isolate to antibiotics so that an appropriate drug can be selected for individual treatment. In 11 patients, affected by urethroprostatitis and suspected of treatment failure with standard drug regimens, either due to lack of compliance with therapy or antibiotic resistance, C.t. was isolated in McCoy cell culture from urethral swabs, after prostatic massage. The in vitro activity of azithromycin against these isolates and the in vivo efficacy of the drug in the patients treated with a single 1 g dose have been evaluated. All the C.t. strains tested were susceptible to the action of azithromycin (MIC range 0.125-1.0 microgram/ml). Bactericidal values were one dilution higher (MBC range 0.25-2.0 microgram/ml). These in vitro results are consistent with clinical observations as all the patients treated had negative culture at a 4-week follow-up visit.

Azithromycin↗
PubMed1993

Chiral discrimination and antipicornavirus activity of 6-oxazolinylisoflavan.

Racemic 6-oxazolinylisoflavan, a highly effective inhibitor of rhinovirus serotype 1B in vitro, was resolved by high-performance liquid chromatography on a chiral stationary phase in order to study the activity of the enantiomers against picornaviruses. The absolute configuration of the two isomers was determined by circular dichroism curves. The antipicornavirus activity of each isomer, separately collected, was evaluated in vitro against human rhinovirus serotype 1B, enterovirus 71, echovirus 6, coxsackievirus B4, and poliovirus type 2 by means of the plaque reduction assay. Both enantiomers were inhibitors of picornavirus replication with the degree of their activity depending on virus and isomer tested.

Antiviral Agents↗
PubMed1992

Mechanism of action of the antirhinovirus flavanoid 4',6-dicyanoflavan.

4',6-Dicyanoflavan (DCF), a new antirhinovirus compound, was shown to inhibit an early event of rhinovirus type 1B replication in HeLa cells. When DCF was present from the beginning of infection or was added no later than the first hour of infection, the compound completely prevented viral RNA and protein synthesis and the virus-induced shutoff of host translation. DCF had no adverse effect either on virus binding to the cell membrane or on virus penetration into cells, whereas it delayed the uncoating kinetics of neutral redencapsidated rhinovirus. DCF also prevented mild acid or thermal inactivation of virus infectivity, although it reversibly interacted with virions. These results suggest that the stabilizing effect of DCF on virion capsid conformation is responsible for uncoating inhibition.

Antiviral Agents↗
PubMed1990

Effect of desferrioxamine B, a metal chelating agent, on rhabdovirus multiplication.

It has been suggested that the antiviral activity shown by chelating agents towards different viruses is probably related to the action on viral nucleic acid polymerases which require metal ions as essential cofactors. Desferrioxamine B, a metabolite from Streptomyces pilosus which chelates ions (Fe3+, Al3+, Cu2+, Zn2+, Co2+) from intracellular and external compartments, has been tested for its activity on the multiplication of VSV and rabies virus in CER cells. While desferrioxamine B was ineffective on rabies virus multiplication, it was shown to reduce plaque formation, cytopathic effect and viral yield by VSV at both low and high multiplicity of infection. The activity of the drug was not due to a direct action on virions outside the cells, but was probably related to an alteration in the delicate balance of intracellular ions which could in turn be critical for VSV multiplication.

Animals↗
PubMedDate not supplied

[Prevention, safety and prophylactic measures in occupational HIV infection in Italy, the European Union and the USA].

Numerous guidelines have been issued by Public Health institutions and related authorities in the last few years for the prevention of HIV infection among occupationally exposed workers. Our study was aimed at comparing the regulations and guidelines on this topic that have recently been adopted by Western countries, also taking into account the impact of the problem in current scientific literature. Health-care workers are the category with the highest risk for occupational exposure to HIV principally associated with accidental needlesticks, skin lesions and percutaneous injuries. In preventive and occupational medicine, Italy, the European Union and the USA have founded their recommendations on universal and specific precautions issued by the Center for Disease Control. Moreover, as long ago as 1990 the Italian Ministry of Health issued official guidelines for the prevention of occupational exposure to bloodborne pathogens. Post-exposure management is crucial for the protection of workers at risk. As a consequence of the failure of some monotherapeutic zidovudine treatments, different countries revised their guidelines and recommended the use of a combination of chemotherapeutic drugs for the post-exposure regimen. However, most of the currently available data are derived from efficacy studies of combined therapy on HIV-infected patients. Therefore, further experimental investigations are needed aimed at evaluating the short- and long-term effects of these treatments in the post-exposure protection of workers at risk for HIV infection.

European Union↗
PubMedDate not supplied

[Vaccine prophylaxis: contribution for the control of biologic risk in exposed workers].

Working activities with exposure to biological agents have become a matter of discussion especially after the introduction in Italy of the Law 626/94, in conformity with the EU directive 90/679/EEC. There are many important biological agents that can have infectious, allergic, toxic or carcinogenic effects on the working population. Large occupational groups are exposed to these biohazards, both in agriculture and industry. Vaccination is one of the most beneficial medical practices, which has led to the eradication of such a devastating human disease as smallpox and the almost total elimination of poliomyelitis. Vaccination is also one of the most cost effective prevention measures applicable in this respect. This paper describes the possible vaccinations that employers should make available to employees exposed to biological risk, according to article 86 of Law 626/94.

Containment of Biohazards↗
PubMedDate not supplied

[SARS and occupational risk].

SARS is an infectious disease caused by a previously unrecognized human coronavirus, called SARS-associated coronavirus (SARS-CoV). Current information indicates that most transmission is via respiratory droplets coming from a person who is symptomatic with SARS ("close contact"). The aim of our study is to evidence the critical role of the family physician, the first health-care worker who cares with suspected/probable SARS patients, underlying the importance of the correct use and management of the personal protective equipment.

Humans↗
PubMedDate not supplied

[Use of the comet test in occupational medicine and industrial toxicology: considerations and prospects].

The comet test (Single Cell Gel Electrophoresis or SCGE) is an easy to perform, rapid and highly sensitive genotoxicity assay; it requires small amounts of biological substrate and is applicable in vivo and in vitro to a wide variety of cells and tissues. Modified versions of the comet test able to detect oxidative damage or the effects of agents inducing DNA-DNA or DNA-protein crosslinks are available. Similarly to other genotoxicity assays, the comet test is not predictive far individual cancer risk. Limitations and critical features presently linked to comet test applications, with particular regard to the biomonitoring of individuals exposed to genotoxic agents, include: lack of sensitivity with respect to aneugens (agents inducing numerical chromosomal aberrations), possible underestimation of genotoxic potency of agents with mixed action mechanisms, sensitivity depending on the genotoxic agent itself, dependence an biological substrate with regard to the influence of cytotoxicity on the assay results, influence of age, tobacco smoke, alcohol and drug consumption, diet, kinetics of DNA adducts and DNA repair mechanisms. Consequently, a routine use of the comet test in biological monitoring of individuals that are occupationally and environmentally exposed to genotoxic agents is submitted to its validation by multicentric studies on large population samples with different exposure patterns, with a suitable characterisation of the role played by the above mentioned factors. Human studies should also be increasingly focused on the direct cellular targets of exposure to genotoxicants (e.g. epithelial cells of oral cavity and airways).

Age Factors↗