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Biomedical subjects

P Payment

Publications and source records attributed to P Payment.

At least 73 records · Page 4Linked to original sources
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

Isolation of viruses from drinking water at the Point-Viau water treatment plant.

Viruses were isolated from every sample of raw (100 L) and treated (1000 L) water collected at a water treatment plant drawing sewage-contaminated river water. Few plaque-forming isolates were formed but cytopathogenic viruses were isolated as frequently in drinking water as in raw water. In drinking water some samples contained more than 1 cytopathogenic unit per litre, but most contained 1-10/100 L. These viruses had not been inactivated or removed by prechlorination, flocculation, filtration, ozonation, and postchlorination. There were no coliforms present and a residual chlorine level had been maintained. Poliovirus type 1 was a frequent isolate but many isolates were nonpoliovirus. The presence of these viruses in drinking water raises questions about the efficacy of some water treatment processes to remove viruses from polluted water.

Cytopathogenic Effect, Viral↗
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↗
PubMed1979

Efficiency of several micro-fiber glass filters for recovery of poliovirus from tape water.

Micro-fiber glass filters from Gelman, Filterite, Johns-Manville, and Whatman were compared with Millipore membrane filters on the basis of their virus adsorbancy, flow rate, clogging resistance, and virus concentration efficiency by using tap water at 2 nephelometric turbidity units. As virus adsorbants the Johns-Manville D39, Filterite 0.25-micron, Filterite 0.45-micron, and Millipore 0.45-micron filters were the most efficient, retaining more than 99% of the added virus in water at pH 3.5 and 0.0005 M aluminum chloride. The Johns-Manville D79 and D49 filters retained 92 and 96% of the virus, respectively, whereas the Whatman GF-D, Whatman GF-F, Gelman A-E, and Millipore AP-20 filters retained only 28, 78, 56, and 34% of the virus, respectively. The best flow rate and clogging resistance were obtained with the Johns-Manville D79 filter or with this filter acting as a prefilter to the Johns-Manville D49, Johns-Manville D39, or Filterite 0.45-micron filter. Finally, poliovirus experimentally seeded in 20 liters of tape water was recovered from Johns-Manville D79-Johns-Manville D39 or Johns-Manville D79-Filterite 0.45 micron 142-mm filter combinations was a efficiencies of 86 and 85%, respectively.

Fresh Water↗
PubMed1979

Production of cells and viruses in a new multiple-tube tissue culture propagator.

A novel method for large-scale culture of anchorage-dependent cells is described. Culture vessels were constructed by using roller bottles and Pyrex tubing. Parallel glass tubes, equally spaced by silicone rings and inserted into the roller bottles, provided an increased culture area. The roller bottles were fitted with a second opening for medium recirculation. Culture vessels of 1,000-, 4,000-, 8,000- and 16,000-cm2 growth area were constructed to propagate Vero, BS-C-1, primary chicken embryo, and IMH-P cells. These cultured cells were used to efficiently produce several viruses: rubella virus, measles virus, poliovirus, cytomegalovirus, and herpesvirus of turkey.

Animals↗
PubMed1979

Enzyme-linked immunosorbent assay for serology of infectious bovine rhinotracheitis virus infections.

An enzyme-linked immunosorbent assay was developed to detect antibodies to infectious bovine rhinotracheitis virus in bovine sera. The test used viral antigen purified in a sucrose density gradient, and the antibody titers detected were up to 100 times higher than those seen in the serum neutralization test. When 250 sera were tested by those two tests, 146 were positive and 49 were negative in both tests. Only 1 serum was negative in the immunoassay test and positive in the neutralization test. However, 54 sera negative in the neutralization test were positive in the immunoassay test. These positive results appear to be in agreement with the increased sensitivity of the enzyme immunoassay.

Animals↗
PubMed1979

Polioviruses as indicator of virological quality of water.

Viruses were found in 47 out of 53 samples of raw domestic sewage collected over a 13-month period from a high socioeconomic level community. At least 39 out of these 47 samples contained polioviruses as was expected in a population where children were receiving Sabin live-attenuated vaccine. Polioviruses could then be used as a suitable indicator of the virological quality of water in communities where Sabin vaccine is used.

Poliovirus↗
PubMed1979

Polioviruses and other enteroviruses in urban sewage from Laval (Canada): presence of non-vaccinal strains of poliovirus.

During a 13-month period (August 1, 1977-August 31, 1978) 55 samples of 2-4 L of raw sewage from an urban residential area were collected and studied for the presence of human enteroviruses. Viruses were recovered from 47 (90.5%) of the samples. Of the 201 viral isolates propagated, 180 (89.5%) were identified by the serum neutralization test as poliovirus types 1,2, or 3; 16 (8%) were identified as coxsackie B viruses; and 5 (2.5%) could not be identified by the methods used. While all polioviruses, types 2 and 3 isolates, were vaccine-like (rct-/d-) or intermediate strains, 14 poliovires, type 1 out of 55 selected isolates, were found to be non-vaccine-like (rct+/d+), 8 were rct-/d-), and 33 were intermediate strains. Out of nine samples submitted to the serodifferentiation (McBride) test, six poliovires, type 1 rct+/d+ and three rct+/d-, were related to wild strains.

Enterovirus↗
PubMed1979

Use of electron microscopy and an enzyme-linked immunosorbent assay for the detection of rotaviruses in neonatal calf diarrhea.

Electron microscopy and an enzyme-linked immunosorbent assay were compared for the diagnosis of rotaviruses associated with neonatal calf diarrhea. One hundred percent correlation was observed when 125 samples were tested by both techniques. Both techniques were equally efficient in detecting rotaviruses. The enzyme-linked immunosorbent assay was more sensitive but being specific could not detect other viruses.

Animals↗
PubMed1978

Detection of Mycoplasma hominis and Mycoplasma orale in cell cultures by immunofluorescence.

Mycoplasma contaminants of animal and human cell cultures were rapidly detected and identified by an indirect immunofluorescent technique. Cells suspected of being contaminated by mycoplasmas were grown as monolayers on chamber slides in a culture medium selected to promote mycoplasmal growth. Before fixation by acetone, the monolayers were subjected to a hypotonic treatment to cause swelling of the mycoplasmas. Detection and identification were then performed by indirect immunofluorescence using rabbit antisera to various mycoplasma species. The correlation between results obtained by the standard isolation procedure and those obtained by this method was very close.

Animals↗
PubMed1978

Thermostable antigens from the bone marrow of several animal species.

Studies on bone marrow extracts from ten animal species have revealed the presence of thermostable antigens. Similar antigens were found in other organs as shown by immunodiffusion and cross-reactivity was demonstrated between the thermostable proteins from horse and dog and between cow and sheep proteins. Using an immunoenzymatic reaction with glucose oxidase as the marker, the thermostable antigens were localized in the blood and bone marrow polymorphonuclear leukocytes and the myeloid cell line.

Animals↗