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Biomedical subjects

R M Pintó

Publications and source records attributed to R M Pintó.

25 records · Page 2Linked to original sources
PubMed1994

Use of the colonic carcinoma cell line CaCo-2 for in vivo amplification and detection of enteric viruses.

The use of the continuous cell line CaCo-2 as an in vivo amplification system for the detection of fastidious human enteric viruses is reported. CaCo-2 cells showed an increased sensitivity to laboratory strains of group A rotavirus 3, reovirus 3, astrovirus 1, poliovirus 1, coxsackievirus A 24, enterovirus 70, and adenovirus 5, 40 and 41, when compared to a routine host cell line for each virus. Nucleic acids from wild-type infectious rotavirus, astrovirus, and adenovirus 40 in stool samples of patients with acute gastroenteritis could be amplified after infection of CaCo-2 cells with trypsin-pre-treated virus inocula. Virus diagnosis was carried out subsequently by dot-blot hybridisation with specific cDNA probes. An amplification factor between 10 and 1,000x was obtained by infection of CaCo-2 cells, thus enabling specific detection of low numbers of a wide range of enteric viruses, and the differentiation between infectious and noninfectious particles.

Adenocarcinoma↗
PubMed1994

Survival of enteric viruses on environmental fomites.

The survival of human enteric viruses on several porous (paper and cotton cloth) and nonporous (aluminum, china, glazed tile, latex, and polystyrene) environmental surfaces has been evaluated. Viruses persisted for extended periods on several types of materials commonly found in institutions and domestic environments. The stability of the viruses was generally influenced by environmental factors such as relative humidity (RH), temperature, and the type of surface contaminated. Overall, hepatitis A virus (HAV) and human rotavirus (HRV) were more resistant to inactivation than enteric adenovirus (ADV) and poliovirus (PV). The resistance to the desiccation step appears to be of major significance in determining the survival of a virus dried on fomites. ADV and PV showed a pronounced decrease in titer at this stage, whereas HAV and HRV displayed little decay at the desiccation step. HAV and HRV persistence was not affected by the presence of fecal material. On nonporous surfaces, PV and ADV persisted better in the presence of feces. However, on porous fomites the presence of fecal material had a negative influence on the survival of PV and ADV. Except for HRV, greater virus survival was observed at 4 degrees than at 20 degrees C. PV and HAV survival was enhanced at high RH; the survival of the latter was enhanced at least for nonporous materials. When dried on porous materials, HRV also exhibited greater persistence at high RH. The survival of ADV was not affected by RH. The validity of using bacteriophages of Bacteroides fragilis as indicators of human viruses dried on fomites was evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoviruses, Human↗
PubMed1994

Disinfection of human enteric viruses in water by copper and silver in combination with low levels of chlorine.

The efficacy of copper and silver ions, in combination with low levels of free chlorine (FC), was evaluated for the disinfection of hepatitis A virus (HAV), human rotavirus (HRV), human adenovirus, and poliovirus (PV) in water. HAV and HRV showed little inactivation in all conditions. PV showed more than a 4 log10 titer reduction in the presence of copper and silver combined with 0.5 mg of FC per liter or in the presence of 1 mg of FC per liter alone. Human adenovirus persisted longer than PV with the same treatments, although it persisted significantly less than HRV or HAV. The addition of 700 micrograms of copper and 70 micrograms of silver per liter did not enhance the inactivation rates after the exposure to 0.5 or 0.2 mg of FC per liter, although on some occasions it produced a level of inactivation similar to that induced by a higher dose of FC alone. Virus aggregates were observed in the presence of copper and silver ions, although not in the presence of FC alone. Our data indicate that the use of copper and silver ions in water systems may not provide a reliable alternative to high levels of FC for the disinfection of viral pathogens. Gene probe-based procedures were not adequate to monitor the presence of infectious HAV after disinfection. PV does not appear to be an adequate model viral strain to be used in disinfection studies. Bacteroides fragilis bacteriophages were consistently more resistant to disinfection than PV, suggesting that they would be more suitable indicators, although they survived significantly less than HAV or HRV.

Adenoviruses, Human↗
PubMed1993

Concentration of fish enveloped viruses from large volumes of water.

The validity of several concentration procedures for the detection of fish enveloped viruses present in large volumes of water was determined. Viral haemorrhagic septicaemia virus (VHSV) was used to evaluate adsorption/elution to positively-charged MK filter cartridges for the concentration of enveloped viruses. For fresh water, the efficiency of the procedure ranged from 12 to 100%, with a mean recovery of 57%. In seawater samples, the recoveries varied from 15 to 100%, with a mean recovery of 59%. The same virus was used in methods such as organic flocculation and ammonium sulphate flocculation with very poor recoveries of infectious virus, caused by the inactivation of VHSV in both procedures. Concentration of seawater samples from tanks housing sea bass or gilthead affected by viral erythrocytic infection and lymphocystis, respectively, were carried out. In both cases, the viruses responsible for the outbreaks were detected by electron microscopy in the concentrated water samples.

Adsorption↗
PubMed1991

The use of bacteriophages of Bacteroides fragilis as indicators of the efficiency of virucidal products.

The potential use of bacteriophage B40-8 of Bacteroides fragilis for the evaluation of the virucidal activity of antiseptics or disinfectants was investigated. The antiviral activity of two antiseptics and two disinfectants was evaluated according to a standard guideline. The effect of the virucidal agents was assessed on (i) viruses usually spread by direct contact with surfaces with contaminated secretions, i.e. herpes virus 1 and 2, and vaccinia virus, and (ii) viruses transmitted by the fecal-oral route, i.e. hepatitis A virus, poliovirus, adenovirus and rotavirus. The survival of B40-8 always equalled or exceeded that of the animal viruses tested. Our data suggest the use of bacteriophage B40-8 to complement the information furnished by some standardized methods in ascertaining the antiviral activity of virucidal preparations.

Anti-Infective Agents, Local↗
PubMed1991

Viral erythrocytic infection in sea bass: virus purification and confirmative diagnosis.

The viral erythrocytic infection (VEI) of sea bass (Dicentrarchus labrax) is evidenced by the presence of inclusion bodies in the erythrocytes and erythroblasts. Virus-like particles (VEIV) about 135-150 nm in diameter were observed in erythroblasts of affected fish. No culturable virus could be recovered from the organs and blood of VEI-affected fish, after inoculation of different fish cell lines. Histochemical staining revealed the presence of RNA but not of DNA in the inclusion bodies. Specific, rabbit hyperimmune sera were prepared after extraction and purification by gel chromatography of viral material from pelleted blood cells of infected fish, and evaluated by immunocytochemical assays. Electron microscopic observations revealed the presence of enveloped particles of about 125-150 nm in the antigenic preparation. The antisera specifically reacted to inclusion bodies, cellular membranes and nuclei of VEI-affected erythrocytes in immunofluorescent and peroxidase-antiperoxidase assays. Immunoelectron microscopy in ultrathin sections of head kidney samples from VEI-affected fish showed recognition of inclusion bodies and virus particles. Confirmative diagnostic procedures could be established through the use of specific anti-VEIV sera, which enabled differentiation between similar syndromes described in other fish species.

Animals↗