Search PubMed⌕ Search

Biomedical subjects

C Dai

Publications and source records attributed to C Dai.

45 records · Page 3Linked to original sources
PubMed1996

[Rapid and simple detection of Ki-ras gene mutations in pancreatic adenocarcinoma by PCR-SSP].

UNLABELLED: In order to judge whether Ki-ras gene mutations are present and their mutation styles, three kinds of special sequence primers (SSP) for polymerase chain reaction with regard to the mutant styles (CGT, GTT and GAT) at codon 12 were used to study the mutations in frozen tissues of pancreatic adenocarcinoma. The amplification products were studied with conventional electrophoresis using acrylamide gels and stained with ethidium bromide to detect the mutations. RESULTS: In 23 of 25 frozen pancreatic adenocarcinoma specimens, Ki-ras genes with mutations at codon 12 were found; 2 mutant styles were found in 8 of the 23 samples; no mutations were found in 11 normal pancreatic tissues, 12 benign pancreatic disease tissues and 3 bile duct carcinoma tissues. This method is rapid, convenient, specific as well as sensitive. We conclude that this may become a valuable diagnostic modality for pancreatic carcinoma and for differentiating benign pancreatic diseases from carcinoma.

Adenocarcinoma↗
PubMed1996

[Expressing poliovirus (type I) and hepatitis A virus antigens by recombinant vaccinia virus].

A recombinant vaccinia virus expressing PV-I and HAV antigens was constructed. Dot blot and Southern blot confirmed that the recombinant virus genome contained PV-I cDNA and HAV cDNA chimeric fragment. The result of IF indicated that PV-I antigen and HAV antigen were successfully expressed in the mammalian cells infected with the recombinant virus. The expressed PV-I and HAV antigen showed one band which had both PV-I and HAV antigenicities in Western blot. The band was about 120,000(MW). When guinea pigs were immunized with the recombinant virus, PV-I and HAV neutralizing antibodies were induced. The result indicated that the recombinant virus constructed here had bi-valence of PV-I and HAV antigen as well as PV-I and HAV immunogenecities.

Animals↗
PubMed1993

[Mouse neurovirulence of antigenic chimeras (type I/II) of polioviruses].

The mouse-adapted Lansing strain of poliovirus type 2 PV-2(L) induces fatal poliomyelitis in mice after intracerebral inoculation, while mice inoculated with Mahoney strain of poliovirus type 1 PV-1(M) show no signs of disease. Previous work had indicated that both the 5' non-translated region of the viral genome and the viral capsid protein, neutralization antigenic site I (N-Ag1), were involved in mouse neurovirulence. In order to further explore the role of N-Ag1 in mouse neurovirulence, antigenic chimeras of two poliovirus strains, XF414 and XF324, were constructed. In the two strains, ten amino acids (in XF414) or 16 amino acids (in XF324) in antigenic site I in Vp1 of PV-I (M) were replaced with a PV-2(L)-specific sequences using a mutagenesis cartridge. Mouse neurovirulence tests indicated that mice cerebral inoculated with XF414 and XF324 developed poliomyelitis leading to paralysis or death. The viruses possessing antigenicity of the inoculating viruses were isolated from cerebral tissues of the paralyzed mice. The results demonstrated that N-Ag1 is an important determinant of poliovirus host range, and may be involved in attachment and penetration of poliovirus (in)to cells of the mouse central nervous system.

Animals↗
PubMed1993

[Studies of purification, inactivity and immunogenicity of antigenically chimeric poliovirus].

Purified viruses were inactivated with 1:4000 formalin at 37 degrees C for 12d. Before and after inactivation, XF414 with anti-PV-1 and anti-PV-2, XF3 with anti-PV-1 and anti-PV-3 were observed by immunoelectron microscopy and the results were positive. Neutralization inhibition test and D-Ag unit detection were conducted, and the results were as follow: XF414 had type 1 D-Ag 15971 units/ml and type 2 D-Ag 15644 units/ml; XF3 had type 1 D-Ag 13314 units/ml and type 3 D-Ag 15971 units/ml. When rabbits were immunized with XF414 and XF3, they produced bivalent antiserum; i.e. anti-PV-1 and anti-PV-2 induced by XF414 and anti-PV-1 and anti-PV-3 induced by XF3.

Animals↗
PubMed1992

Studies on the immunogenicities of intertypic chimeric polioviruses.

To study the relationship between structure and antigenicity, two hybrid viruses, XF414 and XF3, were constructed. In XF414, N-Agl of PV1 was replaced by N-Agl of PV2; while in XF3, N-Ag1 of PV1 was replaced by N-Ag1 of PV3. In this study, XF414 and XF3 were cultured on a large scale in primary monkey kidney cells. The viruses were concentrated with PEG, purified with chloroform and Sepharose 2B and inactivated with formaldehyde. Their bivalent antigenicity was confirmed by neutralization inhibition test, immunoelectron microscopy, and rabbit immunization. It was also shown that both XF414 and XF3 can elicit bivalent neutralizing antibodies and that the bivalent antigenicities are not destroyed by formaldehyde inactivation. Such a study can provide a basis for the development of multivalent picornavirus vaccines.

Animals↗
PubMed1988

Reliability and validity of a Chinese computerized diagnostic instrument.

This paper reports on the development and testing of a new Chinese diagnostic instrument--the Adult Diagnostic Interview Schedule-Present (ADIS-P). This instrument uses a selection of items adapted from DIS and SADS. It is administered within approximately 25 min by a trained clinician using a small portable computer that provides an immediate diagnosis. The instrument was tested on 1,331 patients from six large mental hospitals across the country. The concurrent validity was good: compared to the concensus diagnosis of two senior clinicians (who were blinded to the ADIS-P result), the overall diagnostic accuracy was 83% and the weighted Kappa value was 0.60. The 1 month test-retest reliability was satisfactory (weighted Kappa = 0.55). We conclude that ADIS-P is a convenient, reliable and valid diagnostic instrument.

Adult↗