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Biomedical subjects

M Trudel

Publications and source records attributed to M Trudel.

At least 109 records · Page 6Linked to original sources
PubMed1983

Microbial investigation of the air in an apartment building.

The microbial and viral flora in the ventilating ducts of an apartment building was evaluated. Several types of sampler (slit sampler, Andersen sampler, large volume air sampler) were used to evaluate the hourly, weekly and seasonal variation of this flora. The mean bacterial concentration was 17.2 e.f.u./m3 with a maximum level at 07.30 h (41.3 c.f.u./m3) and a minimal concentration in the early afternoon (8 c.f.u./m3). The bacterial concentration observed correlated with the relative humidity in the air-ducts although there were no seasonal differences. The bacteria were mainly gram-positive cocci (73.5%) represented by a large number of Micrococcaceae (47.1%); gram-positive bacilli accounted for 14.2% of the isolates, gram-negative bacilli 12.0% and gram-negative cocci 0.3%. The majority of the bacteria-carrying particles were in the respirable range with 80.4% of them being less than 5 microns. The methods used did not result in the isolation of viruses during the winter sampling period.

Air Microbiology↗
PubMed1983

A survey of enteric viruses in domestic sewage.

In this second study (1979-1981) of the viral content of sewage we have demonstrated the presence of poliovirus types 1, 2, and 3 in Laval and Montreal. Several strains of poliovirus types 2 and 3 were nonvaccinal. This is in contrast with our first study (1977-1978) in which only type 1 poliovirus isolates were nonvaccinal. Coxsackievirus types B-3, B-4, and B-5 and echovirus types 1, 7, and 11 were also isolated from sewage. Interestingly, these isolations coincided with reports of isolation of the same strains during the same period by diagnostic laboratories. Our method based on Vero and BSC-1 cell cultures for virus isolation and immune electron microscopy for identification permitted the recovery not only of several strains of enteroviruses but also of some adenoviruses and reoviruses.

Adenoviridae↗
PubMed1982

Transcription units around the gene for E. coli translation initiation factor IF3 (infC).

The coding properties have been analyzed of in vitro constructed lambda recombinant phages carrying E. coli DNA fragments from around the structural gene for translation initiation factor IF3 (infC). This study shows that infC is expressed independently of the promoter of the threonyl-tRNA synthetase (thrS), which is the genes immediately preceding infC. It also shows that the two genes following infC, namely pheS and pheT, which form the phenylalanyl-tRNA synthetase operon, are not expressed from infC's promoter. Thus the four characterized genes of that region that were previously thought to be transcribed in the same direction are now shown to be expressed in vivo as three separate transcription units.

DNA, Bacterial↗
PubMed1982

Rapid identification and serotyping of poliovirus isolates by an immunoassay.

An enzyme-linked immunosorbent assay (ELISA) for the identification and typing of polioviruses is described. Polioviruses could be rapidly detected and typed from cell culture supernatants by a double antibody sandwich technique. The assay is valuable for the rapid screening of a large number of viral isolates from water samples submitted for virological analysis. Several hundred isolates per day can be typed and only the remainder have to be tested by the conventional serum neutralization test.

Antibodies, Viral↗
PubMed1982

Antibody response to rubella virus proteins in different physical forms.

The immunogenicity of different antigens, containing rubella virus hemagglutinating (HA) membrane protein, was studied using live virus, beta-propiolactone-inactivated virus, detergent and lipid-free octamers and virosomes. Whole virus particles, live or inactivated, induced hemagglutination inhibition (HAI) antibodies in rabbits after one subcutaneous injection of 0.16 micrograms of HA protein. Hemagglutinin rosettes or virosomes failed to induce antibodies even at a dose of 120 micrograms. Apparently, the extraction of viral membrane hemagglutinin, for the preparation of a rubella subunit vaccine, led to destruction of the antigenicity responsible for the induction of hemagglutination inhibiting antibodies. These results are discussed in the light of earlier studies on the preparation of a rubella subunit vaccine.

Animals↗
PubMed1981

Characterisation of rubella virus hemagglutinin rosettes.

Purified rubella virus treated with Triton X-100 was subjected to centrifugation in a sucrose density gradient containing nonionic detergent beta-D-octylglucoside. The result of this treatment was the formation of hemagglutinating rosettes containing viral glycoproteins VP2 (50,000 mol. wt.) and VP3 (63,000 mol. wt.). The rosettes have a 26 S sedimentation coefficient and a density of 1.2 g/cm3 in sucrose. Electron microscopy revealed 15 nm rosettes with a hollow center. The molecular weight of the rosettes was extrapolated at 850,000.

Centrifugation, Isopycnic↗
PubMed1981

Purification of infectious rubella virus by gel filtration on sepharose 2B compared to gradient centrifugation in sucrose, sodium metrizoate and metrizamide.

Rubella virus was purified by chromatography on Sepharose 2B after concentration by ultrafiltration on hollow fibers and hydroextraction with PEG 20,000. Yields of 40% infectivity and 70% hemagglutinating activity were routinely obtained. Chromatographic purification was compared to ultracentrifugation in sucrose, metrizamide and sodium metrizoate. Yields were lower in sucrose and metrizamide, while sodium metrizoate reduced the infectivity of the virus below detectable levels. These results demonstrate the advantage of Sepharose 2B for the purification of infectious rubella virus.

Centrifugation, Density Gradient↗
PubMed1981

Rubella virosomes: preparation and ultrastructure.

Rubella virosomes were prepared from performed liposomes and detergent solubilized viral hemagglutinin. The liposomes were made from lecithin/dicetyl phosphate (3.5 : 1) films resuspended in NTE buffer and sonicated. Viral hemagglutinin was prepared from purified virus after solubilization with Triton X-100 and centrifugation through a sucrose gradient containing beta-D-octylglucoside. Electron microscopy of the rate zonal purified virosomes, showed virus-like structures of 40 - 80 nm. The virosomes retained the biological activity of the hemagglutinin and had a buoyant density of 1.2 g/cm3.

Centrifugation, Density Gradient↗
PubMed1981

Concentration of human respiratory syncytial virus using ammonium sulfate, polyethylene glycol or hollow fiber ultrafiltration.

Human respiratory syncytial virus was concentrated by polyethylene glycol or ammonium sulfate precipitation as well as by hollow ultrafiltration. Recoveries obtained were respectively 49.4%, 47.7%, and 75.2%; however, further analysis of these results by resuspension experiments showed that all the infectivity could be recovered from the different concentrates. The protein content of polyethylene glycol concentrates was much lower than those of ammonium sulfate or hollow fiber ultrafiltration. Electron microscopy revealed that the morphological integrity of virus particles was unaffected by the concentration methods used. Purified virus was obtained when polyethylene glycol concentrates were centrifuged through two successive density gradients.

Ammonium Sulfate↗
PubMed1981

Effect of oligonucleotide AGAGGAGGU on protein synthesis in vitro.

The oligonucleotide AGAGGAGGU, complementary to the 3' end of 16S RNA has been shown to inhibit 70S initiation complex formation on E. coli ribosomes (Taniguchi, T. and Weissmann, C., 1978. Nature, 275, 770-772). We have prepared this nonanucleotide in larger quantities by a combination of DEAE cellulose-urea chromatography and reverse phase (RPC 5) chromatography. The inhibitory effect of AGAGGAGGU on initiation complex formation has been confirmed. Furthermore, when added to a complete system for in vitro protein synthesis, the translation of Q beta RNA was inhibited by the nonanucleotide. No selectivity was observed in the inhibition of the coat protein and replicase protein synthesis. When both Q beta RNA and pAUG were present, some stimulation of pAUG binding to 70S ribosomes was observed on addition of AGAGGAGGU, as previously reported (Taniguchi and Weissmann, ibid). No effect was observed in the absence of Q beta RNA. This observation is discussed.

Escherichia coli↗
PubMed1981

Virosome preparation: differences between influenza and rubella hemagglutinin adsorption.

Rubella and influenza virosomes were prepared from preformed liposomes or dried lipid films with or without nonionic detergent beta-D-octylglucoside. The preformed liposomes and lipid films were prepared from lecithin and dicetyl phosphate (3.5:1). Viral hemagglutinin rosettes were prepared from purified viruses after solubilization with Triton X-100 (1%), centrifugation through a continuous sucrose gradient containing 30 mM octylglucoside, and dialysis. Analysis of virosomes by sucrose density gradient centrifugation, hemagglutination assay, and electron microscopy revealed that rubella hemagglutinin did not require the presence of detergent to form virosomes, whereas influenza hemagglutinin could absorb efficiently to liposomes only in the presence of detergent.

Adsorption↗
PubMed1980

A simple and rapid microassay for the titration of human respiratory syncytial virus.

A microassay, using tissue culture microplates for the titration of human respiratory syncytial virus by syncytium formation, is described. Virus titers obtained agreed well with those obtained in a larger assay system; the microassay, however, is more rapid and economical. Large numbers of virus samples are easily and rapidly processed as the assay necessitates an incubation period of only three days.

Animals↗
PubMed1980

Comparison of the hemagglutination inhibition procedure and an enzyme-linked immunosorbent assay for detection of specific antibodies to pneumonia virus of mice in experimentally infected laboratory rats.

An enzyme-linked immunosorbent assay (ELISA) and the hemagglutination inhibition (HI) test were used to evaluate the response of laboratory rats to experimental infection with pneumonia virus of mice. The ELISA procedure was more sensitive than the HI test and detected very low levels of antibodies early in the course of infection. At 5 days postinfection, ELISA detected antibody increases in five of five animals, whereas only two of five increases were detected by the HI test. At 9 days postinfection, the HI test failed to detect one titer increase measured by ELISA. Later during the course of infection, increases were detected by both tests. The ELISA procedure was, in general, more sensitive for detecting low levels of antibody than was the HI test, but was equal in sensitivity when high titers of antibody were measured.

Animals↗
PubMed1980

Reconstitution of rubella hemagglutinin on liposomes.

The hemagglutinin of rubella virus has been purified by differential centrifugation through a sucrose density gradient after disruption of purified virus with Tween 80-ether. The purified isolated hemagglutinin was than adsorbed on liposomes which had been prepared by mixing lecithin and dicetyl phosphate in a 3.5:1 molar ratio. The complex of hemagglutinin adsorbed on the virosomes had a higher sedimentation rate, enabling their separation from free hemagglutinin. It was thus possible to obtain a pure preparation of virosomes by rate zonal centrifugation in a sucrose density gradient containing 0.5 M NaCl. Immunoelectron microscopy showed aggregation of these virosomes with a rubella immune antiserum; this would suggest that the HA subunits are oriented in the same way as on the whole virus.

Adsorption↗
PubMed1980

Concentration and purification of rubella virus hemagglutinin by hollow fiber ultrafiltration and sucrose density centrifugation.

Large volumes of rubella virus were produced in Vero cell monolayers which were grown in the Corbeil-Bellco TM system. Infectious tissue culture fluids were concentrated at least 600 times in less than 4h by ultrafiltration on hollow fibers with a molecular weight cutoff of 100 000. Recovery of the hemagglutinating activity was 75%. Rubella virus was purified by three successive sucrose density gradient centrifugations using a combination and discontinuous and linear gradients. Specific activity was increased 1000-fold.

Centrifugation, Density Gradient↗