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Biomedical subjects

A M Quero

Publications and source records attributed to A M Quero.

At least 37 records · Page 2Linked to original sources
PubMed1986

[Clostridium difficile and its cytotoxin in the stools of young hospitalized children. Influence of antibiotic treatment].

Clostridium difficile has been searched in 153 stool samples from 138 children aged 0 to 12 months. We divided the population in two groups depending on the antibiotic treatment. We have found C difficile in 39 samples (25%). The colonization rate increases with age ranging from 5% before 1 month, to 36% between 1 and 6 months and 54% between 6 and 13 months. An environmental sampling yielded once C difficile. Contamination may be related to the environment. 29% of the isolates produced a cytopathic toxin. Toxin titers in infants' stools range from 1/160 to 1/10240. One only of these children had diarrhea. C difficile and its toxin does not seem to infer any signs of enteric illness with infants. The results obtained with the group of non treated infants are not significantly different from the ones of the other group: the colonization rates are 21% in the non treated group and 29% in the other group. The rate of strains yielding a cytophatic toxin is similar in the 2 groups. It seems reasonable to agree that antibiotics do not influence the settlement of C difficile in infants' intestine.

Aging↗
PubMed1985

Enhanced resistance of mice against influenza virus infection after local administration of glycoprotein extracts from Klebsiella pneumoniae.

RU. 41 740, a glycoprotein extract from Klebsiella pneumoniae O1K2 strain was tested for its ability to enhance resistance of mice against influenza virus infection. Local (aerosol) and systemic (IP) routes of RU. 41 740 administration were compared for their effectiveness in protecting mice. When RU. 41 740 was administered prophylactically (10 mg/kg) via aerosol route (5 consecutive days before challenge), significant protection (P less than 0.0001) was conferred against lethal aerosol inoculation of influenza virus. Treated mice exhibited a reduced mortality, a decreased lung-to-body weight ratio and lower intrapulmonary virus titers. The main glycoprotein soluble fraction (RU. 41 821) was as active as the total glycoprotein extract (P less than 0.0001). Whereas the local (aerosol) route of administration was effective, the systemic (intraperitoneal) route of administration did not confer significant protection against an aerosol inoculum of virus. This finding suggests the important role of local immunity. The levels of interferon in the lavage fluids of immunized and infected mice suggest that interferon is not the main protective mechanism. The enhanced protection observed could be related to an augmented humoral or cell-mediated response within the lung.

Adjuvants, Immunologic↗
PubMed1985

[Augmentation by dilution of the effect of PVP iodine on poliomyelitis virus type I].

The influence of dilution of povidone-iodine solutions on virucidal activity against poliovirus type 1 was investigated. After exposure to different concentrations of povidone-iodine, the reduction in virus titer was determined after separating the antiseptic by gel filtration. Diluted preparations (0.5 and 0.25%) achieved a greater reduction in virus titer (10(5) in one hour) than the 5% stock solution (10(3)). Moreover, dilute solutions exhibited a faster virucidal activity.

Microbial Sensitivity Tests↗
PubMed1984

[Determination of the virucidal activity of antiseptics by a gel filtration method].

The authors propose a method for determining the virucidal potency of antiseptics, in which separation of antiseptic from virus is achieved by filtration through a gel of Sephadex LH20. The antiseptic is trapped within the gel while the virus passes through. Thus, the cytotoxic effect of the antiseptic, which usually hinders virus titration, is eliminated. Two filtration devices were developed: one is a polypropylene syringe, and the other is made of stainless steel. Determination of the effect of four products on poliovirus type I shows that this method allows classification of their activities.

Anti-Infective Agents, Local↗
PubMed1984

[Evaluation of the cytotoxicity of an antiseptic by a photometric micromethod].

Cytotoxicity of an antiseptic is usually evaluated by microscopic examination of a cell culture, after a set time of contact with the antiseptic. As this evaluation is largely subjective, a photometric method is proposed. The procedure consists in staining the cells by methylene blue after contact with the ATS and measuring the dye in a photometer after elution. Different dilutions of ATS are added to a 24 h-monolayer of Vero cells in a 96-well microtissue culture plate (8 wells for each dilution, 8 wells for cell control, and 8 wells for control of dye fixation by the plastic plate). The plate is incubated for three days at 37 degrees C in an atmosphere of 5% CO2 and 95% air. The plate is washed with PBS to remove dead cells and adherent cells are fixed. The plate is then washed with borate buffer and allowed to dry. The dye is eluted by adding 200 microliter of HCl 0.1 N to each well. The plate is then read automatically at 650 nm on a Titertek Multiskan, a vertical light path photometer. Cytotoxicity is expressed as the percentage of damaged cells as compared to control wells. Cytotoxic assay of glutaraldehyde shows that this technique is more reliable and more sensitive than microscopic examination. Moreover, result of cytotoxic assay and of a method consisting in measurement of protein in residual cells after exposure to ATS are significantly correlated.

Animals↗
PubMed1983

Influence of inhaled cadmium microparticles on mouse influenza pneumonia.

A study of the effect of inhaled cadmium microparticles (CdO) on the mouse death rate from influenza pneumonia was performed on 936 female specific pathogen-free (SPF) Swiss mice. The test animals received a single short (15 min) exposure to 9 mg Cd/m3 of air (acute exposure), or renewed short exposures to 1 mg/m3 once a day, 5 days a week, for 4 weeks (chronic exposure). The cadmium found in the trachea-bronchus-lung area was about 5 micrograms/g of fresh tissue at the end of acute exposure, and 4 micrograms/g at the end of chronic exposure. The viral challenge was performed 48 hr after acute exposure, or on the 14th day after the beginning of chronic exposure, the mice being reexposed to Cd for an additional 14 days in the latter case. Surprisingly, the infectious death rate of test mice was significantly lower than that of controls, both for acute and chronic exposure to CdO. These results are discussed.

Aluminum Oxide↗
PubMed1982

Opposite effects of inhaled cadmium microparticles on mouse susceptibility to an airborne bacterial and an airborne viral infection.

An experimental study on 489 mice is reported. The test animals were submitted to a single 15-mn exposure to atmosphere containing about 10 mg of cadmium microparticles (CdO) per m3 of air and the controls to an equivalent amount of aluminium microparticles (Al2o3). At the 48th hour after exposures, the test and control mice were submitted to a bacterial (Pasteurella multocida) or to a viral (Orthomyxovirus influenzae A) challenge, via the respiratory route. The exposure to cadmium significantly increased the death-rate of mice submitted to the bacterial challenge, but it significantly decreased the death-rate following the viral challenge.

Air Pollutants↗
PubMed1982

The effect of alcohol ingestion on the susceptibility of mice to viral infections.

The influence of acute alcoholization on the evolution of different viral diseases was studied in orally alcoholized mice. Ethanol increased mice susceptibility to encephalomyocarditis and influenza only when it was administered after virus infection. There was no dose-effect correlation. Vaccinia and Herpes virus infections were not modified by alcoholization. Hypotheses concerning the mechanisms of alcohol action were put forward.

Animals↗