PubMed Health⌕ Search

Biomedical subjects

A M Quero

Publications and source records attributed to A M Quero.

At least 19 recordsLinked to original sources
PubMed1992

Effect of nanoparticle-bound ampicillin on the survival of Listeria monocytogenes in mouse peritoneal macrophages.

The efficacy of ampicillin bound to polyisohexylcyanoacrylate nanoparticles was studied in vitro in mouse peritoneal macrophages infected with Listeria monocytogenes. Nanoparticles containing ampicillin 1 mg/L were more effective after 30 h than free ampicillin at the same concentration, with viable counts of 3.68 and 5.43 log10 cfu/mL, respectively. The nanoparticles acted on the intracellular bacteria after a lag period of 6-9 h; this time was apparently required for the degradation of the polymer. At the doses used in these experiments, empty nanoparticles had neither an anti-listeria nor a cytotoxic effect.

Ampicillin↗
PubMed1990

Production of interleukin 1 and tumour necrosis factor activities in bronchoalveolar washings following infection of mice by influenza virus.

Mice were infected with influenza A virus by aerosol. Bronchoalveolar washings obtained from infected mice contained interleukin 1 (IL-1) and tumour necrosis factor (TNF) activities. IL-1 was present at day 4 post-infection but not at day 7. TNF activity was present at day 4 and day 7 post-infection. The presence of both these monokines was coincident with increased cell populations in the lungs. In vitro studies demonstrated that macrophages from non-infected mice produce IL-1 and TNF activities in response to live influenza A virus stimulation. These results suggest that a direct interaction between virus and alveolar macrophages leads to IL-1 and TNF production during the course of infection and could account for both the immune responses and the pathology that occur during influenza A virus infection.

Animals↗
PubMed1988

Specific binding characteristics of high affinity monoclonal antidigitoxin antibodies.

The specificity of various monoclonal antidigitoxin antibodies was characterized using 6 cardiac glycoside analogs. Spleen cells from BALB/c mice, immunized with BSA- or KLH-digitoxin conjugates, were fused with NS1 myeloma cells, and antibody-producing hybrids were identified by radioimmunoassay. Twenty-one monoclonal antidigitoxin-specific antibodies were obtained, 10 of which were cloned and characterized for affinity and specificity. All the antibodies had a high affinity constant, ranging from 8.10(8) to 2.5.10(10) 1/M. On the basis of their binding specificities, the antibodies could be classified into 3 groups: the first contained 7 antibodies exhibiting high cross reactivity (42-100%) with digitoxigenin, whereas the second and third groups did not recognize this analog (cross-reactivity of 1%). In the former group, the absence of the sugar moiety only slightly affected the binding reaction, although for the two other groups, this structure did appear to be involved in antibody recognition. Changes in the functional groups of the hapten molecule led to considerable changes in the antibody-antigen reaction. For all the antibodies except one, saturation of the lactone ring considerably affected binding. These results demonstrated that monoclonal antibodies of different specificities with respect to both the steroid backbone and the sugar moiety of digitoxin can be induced using a digitoxin-protein conjugate.

Animals↗
PubMed1987

Effects of RU 41740 aerosol treatment on mouse bronchoalveolar cells, and protection afforded against influenza virus infection.

RU 41740, an immunomodulating compound extracted from Klebsiella pneumoniae, was previously shown to enhance mice resistance to bacterial and viral lung infections. To explore lung defense mechanisms, we studied the influence of RU 41740 aerosol treatment on the bronchoalveolar cell populations. Five successive daily RU 41740 aerosol treatments induced a large accumulation of leukocytes in the lungs 4h after the last treatment. Polymorphonuclear leukocytes predominated. The numbers of lymphocytes and monocytes rose significantly. A single RU 41740 aerosol treatment significantly raised the number of polymorphonuclears only. A luminol-dependent chemiluminescence assay was used to test the effect of RU 41740 on the opsonized zymosan induced response of alveolar macrophages. In vitro, addition of RU 41740 enhanced this chemiluminescence. After a single RU 41740 aerosol treatment of mice, the chemiluminescence of purified alveolar macrophages from these mice increased significantly. The protective effect of five daily RU 41740 aerosol treatments against influenza virus infection was believed to be due to the great intensity of the cellular response and the polymorphonuclear influx. The alveolar macrophage activation observed might also explain the enhanced resistance of mice to influenza virus infection.

Adjuvants, Immunologic↗
PubMed1987

Enhancement of bronchoalveolar cell recovery and stimulation of alveolar macrophage chemiluminescence and resistance to influenza virus after treatment with RU 41821 aerosol.

Aerosol treatment with RU 41821, a glycoprotein extract from Klebsiella pneumoniae, was tested in mice for its effect on the kinetics of the induction of bronchoalveolar cells (i.e., alveolar macrophages, monocytes, lymphocytes, and polymorphonuclear leukocytes). RU 41821 led to an increase in the total number of bronchoalveolar cells. The largest increase was observed for polymorphonuclear leukocytes, and more moderate increases occurred in the numbers of alveolar macrophages, monocytes, and lymphocytes. The alveolar macrophages recruited in response to RU 41821 were activated, as indicated by luminol-dependent chemiluminescence in response to stimulation by opsonized zymosan. The effects of five RU 41821 aerosol treatments and those of a single treatment were further examined in vivo by aerosol infection of mice inoculated with a mouse-pathogenic influenza virus. The maximum protective effect was obtained after five once-a-day treatments and was correlated with the largest increase in the total number of bronchoalveolar cells.

Aerosols↗
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↗