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C S Choi

Publications and source records attributed to C S Choi.

68 records · Page 4Linked to original sources
PubMed1990

Replication of two porcine parvovirus isolates at non-permissive temperatures.

Previous studies have shown that replication in vitro of the porcine parvovirus (PPV) isolate, KBSH, was restricted at 39 degrees C but not at 37 degrees C. In contrast, replication of the Kresse isolate was restricted at 37 degrees C but not at 39 degrees C. In this study, Kresse and KBSH isolates were passaged up to ten times in swine testicle (ST) cells at non-permissive temperatures, and at subsequent passage viral protein synthesis, viral DNA synthesis, and progeny virus were evaluated. KBSH became adapted for replication at 39 degrees C upon serial passages, displaying an appreciable increase in viral progeny, viral polypeptides, and viral DNA concentration. This finding was also observed with Kresse virus isolate continuously passaged at 37 degrees C. Neither isolate became adapted for replication at 32 degrees C. In an attempt to examine the effect of in vitro passage at non-permissive temperatures on pathogenicity in swine, KBSH passaged 10 times either at 37 degrees C or 39 degrees C was inoculated into swine fetuses. Two of four fetuses inoculated with 39 degrees C-passaged KBSH were dead and hemorrhagic or mummified. All four fetuses inoculated with 39 degrees C-KBSH contained viral antigen and viral DNA. In contrast, fetuses inoculated with 37 degrees C-passaged KBSH, or with cell culture fluid were normal in appearance. Viral antigen and viral DNA were not demonstrated in fetuses inoculated with 37 degrees C-KBSH or cell culture fluids. These findings suggest the possibility that the ability to replicate at 39 degrees C is associated with virulence in swine fetuses.

Animals↗
PubMed1990

Detection of porcine parvovirus using nonradioactive nucleic acid hybridization.

Nonradioactive slot blot hybridization assays were established for the detection of porcine parvovirus (PPV), using either a digoxigenin-labeled DNA probe or a biotinylated RNA probe. All probes were prepared from a 3.3-kb Pst1-EcoR1 DNA fragment of the NADL8 isolate of PPV. The sensitivity and specificity of the probes in a slot blot system were evaluated in comparison with a 32P-radiolabeled RNA probe. Using an anti-digoxigenin alkaline phosphatase detection system, at least 1 ng of viral replicative form (RF) DNA, or the equivalent of 100 plaque forming units (PFU) of infectious virus, could be detected by the digoxigenin-labeled DNA probe. When the biotinylated RNA probe and a strepavidin-alkaline phosphatase detection system were employed, 0.1 ng of RF DNA, or the equivalent of 10 PFU of infectious virus, were detected, comparable to the sensitivity of the 32P-radiolabeled RNA probe. Hybridization was not observed with control DNA samples extracted from swine testicle cells, porcine kidney (PK-15) cells, uninfected mixed swine fetal tissue, or from an unrelated DNA virus (pseudorabies virus) infected PK-15 cells. Different isolates of PPV, namely NADL8, NADL2, KBSH, and Kresse, reacted on an equimolar basis in sensitivity and specificity to the biotinlyated probe. Extraction of DNA directly on the filter membrane (direct filter hybridization) was employed in an attempt to reduce processing time by eliminating DNA extraction steps. Direct filter hybridization was indeed less time consuming; it was also comparable in sensitivity and specificity to those methods employing purified DNA.

Animals↗
PubMed1989

Temperature dependent replication of porcine parvovirus isolates.

The replication of four porcine parvovirus isolates, NADL-8, NADL-2, KBSH, and Kresse, in swine testes cells were compared at temperatures of 32, 37, and 39 degrees C. Replication of the Kresse isolate was restricted at 32 and 37 degrees C as evidenced by progeny virus, virus polypeptide and viral DNA synthesis, but not at 39 degrees C. In contrast, replication of KBSH was restricted at 39 degrees C, but not at 37 or 32 degrees C. Findings from this study support the contention that replication of KBSH and Kresse isolates are temperature dependent.

Animals↗
PubMed1987

Inhibition of porcine parvovirus replication by empty virus particles.

The influence of empty porcine parvovirus (PPV) particles on viral replication was examined in cell cultures and in swine. Following extensive purification, homogeneous preparations of full and empty PPV preparations were obtained and used for in vitro and in vivo analyses. In the first in vitro experiment, swine testes cells were infected with mixtures of various ratios of empty and full (E/F) particles. The production of both intracellular and extracellular virus was markedly inhibited in the presence of empty particles. This inhibition was dependent upon the concentration of empty particles present in the mixture. In the second in vitro study, various concentrations of empty particles were added prior to full virus infection. Again, marked inhibition of progeny virus production was evident and related to the concentrations of empty particles added. Based on the results of in vitro studies, the influence of empty particles on PPV infection in swine was tested by infecting mid-term and late-term gestation swine fetuses with various E/F particle ratios. Both mid-term and late-term fetuses exposed to 0:1, 1:1 and 5:1 E/F ratios displayed gross pathological evidence of PPV infection whereas fetuses exposed to E/F ratios of 30:1 or greater were grossly normal in appearance. However, fetuses infected with 30:1, 50:1 and 300:1 E/F ratios showed evidence of virus in their tissues by DNA hybridization. Regardless of the E/F ratios, late-term infected fetuses responded with high antibody titers ranging from 1024 to 4096. The results from these studies suggested that empty particles interfered with viral replication in both cell culture and in animals.

Animals↗
PubMed1987

Pathogenicity of a skin isolate of porcine parvovirus in swine fetuses.

The pathogenic properties of a skin isolate of porcine parvovirus (PPV), designated Kresse isolate, were compared with NADL-8 isolate, a prototype isolate of PPV, by in utero inoculation of mid-term and late-term gestation swine fetuses. Fetuses from pregnant sows of mid-gestation were inoculated with either NADL-8 or Kresse virus. Both isolates were highly pathogenic to mid-gestation fetuses. In contrast, dramatic differences in pathogenicity between these 2 isolates were observed in fetuses inoculated late in gestation. Such fetuses from each of 4 sows were inoculated with NADL-8 or Kresse virus isolate and sacrificed at 10, 18, 21, or 23 days postinoculation (PI). NADL-8-inoculated fetuses were grossly normal. The pathogenic effects of Kresse isolate were evident by gross pathology in fetuses collected at 18, 21, and 23 days PI, but not at 10 days PI. Hemagglutination (HA) and fluorescent antibody (FA) methods were used to identify virus in various tissues of late-gestation fetuses collected at 10 and 21 days PI. At 10 days PI, HA antigens were detected only in livers of NADL-8-inoculated fetuses, but in all tissues examined of Kresse-inoculated fetuses, including the brain. PPV specific fluorescence was demonstrated in tissues of fetuses inoculated with NADL-8 and Kresse virus. The major difference was that virus antigen was found in the brains of fetuses inoculated with Kresse virus, but not in NADL-8 infected fetuses. At 21 days PI, HA antigen was not detected in any of the tissues of fetuses inoculated with NADL-8 virus, with PPV specific fluorescence by FA being found only in the kidney. However, fetuses inoculated with Kresse virus displayed HA antigen in liver and PPV-specific fluorescence in all tissues tested including the brain. Both isolates induced similar antibody responses, 1:128 to 1:256 at 10 days and 1:512 to 1:1024 at 21 days PI. In addition, immunoglobulin G (IgG) deposits were demonstrated in kidneys and skin of fetuses inoculated with Kresse virus and IgM in brain, but not in tissues from fetuses inoculated with NADL-8 virus.

Animals↗
PubMed1987

Changes in end tidal CO2 and arterial blood gas levels after release of tourniquet.

We studied nine healthy adult patients having orthopedic surgical procedures requiring the use of a tourniquet under general anesthesia with controlled mechanical ventilation to determine changes in end tidal CO2 (EtCO2) and arterial blood gas values after tourniquet deflation. After deflation of the tourniquet, EtCO2 and PaCO2 increased maximally within one minute; EtCO2 returned to baseline at a mean time of 13 minutes 7 seconds +/- 5 minutes 17 seconds, while PaCO2 was still above baseline when the study was terminated. The pH level decreased significantly, with the maximal fall occurring within four minutes; it remained below baseline when the study was terminated. The PaO2 level decreased and the bicarbonate level increased, though neither change was statistically significant. After tourniquet release, hyperventilation may be indicated to facilitate the return of PaCO2 and pH levels to baseline; in patients whose acid-base status is compromised by preexisting disease, PaCO2 and pH should be monitored closely. The PaCO2 level could be predicted by monitoring the EtCO2 level.

Adult↗
PubMed1984

Factors affecting the consecutive and simultaneous coupling with bis-diazotized benzidine of protein antigen to sheep red blood cells.

The dynamics of attaching antigen to sheep red blood cells using bis-diazotized benzidine ( BDB ) were studied using purified protein derivative tuberculin as antigen. Factors considered were the concentration of antigen and BDB , temperature, time, and simultaneous or consecutive coupling. Simultaneous coupling at 42 degrees C for 10 min gave the most specific haemagglutination reactions and was simple to carry out.

Animals↗
PubMed1984

Specificity of purified protein derivative extracts from ten species of Mycobacteria killed with phenol in the haemagglutination and haemagglutination inhibition test.

The specificity of purified protein derivative (PPD) extracts from 10 species of Mycobacteria killed with phenol was evaluated using the haemagglutinin (HA) and haemagglutination inhibition (HI) tests. The HA test showed many cross-reactions with homologous and heterologous antisera. In the HI test, many antisera cross-reacted with most PPD extracts. The PPD extracts from Mycobacterium foruitum and M. smegmatis were the most specific. It was concluded that PPD extracted from unheated bacilli was not sufficiently specific for use in HI tests.

Animals↗
PubMed1982

The comparative tuberculin test in guinea pigs using PPD extracts prepared from mycobacteria killed with phenol.

Purified-protein-derivative (PPD) extracts were prepared from Mycobacterium tuberculosis (PPD-S), M. bovis (PPD-BS), M. avium (PPD-A) and M. kansasii (PPD-K), after killing the cultures with phenol. The reactions were assessed in guinea pigs sensitised to a range of mycobacteria, with a view to selecting a suitable pairing of the extracts to distinguish sensitivity due to M. tuberculosis or M. bovis from that due to other mycobacteria. Sensitisation induced by M. bovis was best distinguished from others using PPD-S and PPD-A; for sensitisation by atypical mycobacteria, PPD-BS was better than PPD-S, used with either PPD-K or PPD-A. PPD-BS was more specific than PPD-S. Using PPD-BS, PPD-A and PPD-K in a comparative test, 3 groups were recognised: those sensitive to M. bovis or M. tuberculosis (greatest reaction was to PPD-BS); those sensitive to M. avium, M. intracellulare and M. scrofulaceum (greatest reaction was to PPD-A); those sensitive to M. kansasii, M. marium, M. gordonae and M. fortuitum (greatest reaction was to PPD-K).

Animals↗
PubMed1981

Specificity of purified protein derivative extracts from cultures of mycobacteria killed by phenol.

Purified protein derivative (PPD) extracts were prepared from Mycobacterium bovis, M tuberculosis, M kansasii, M marinum, M avium, M intracellulare, M gordonae and M fortuitum. The cultures were killed with phenol before extraction and were not subjected to heat. They were tested in guinea pigs sensitised with killed cultures of homologous or heterologous species of mycobacteria. The most specific extract was from M fortuitum. M bovis and M tuberculosis were closely related, with M bovis PPD the more specific of the two. A close relationship was shown between M scrofulaceum, M avium and M intracellulare.

Animals↗
PubMed1980

Circumsuture treatment for varicosities.

A surgical procedure that can be used either as an alternative to saphenous vein stripping or as a supplement to it has been developed and used successfully at the Straith Clinic for the past 12 years. The method avoids surgical scars and pigmentation, is simple enough to do with use of local anesthesia, and does not require hospitalization. That the patient can remain ambulatory is another desirable feature. Follow-up of 16 patients who have undergone this procedure has been very encouraging.

Aged↗