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Biomedical subjects

C C Pao

Publications and source records attributed to C C Pao.

At least 37 records · Page 2Linked to original sources
PubMed1995

Differential expression of cytokine genes in cervical cancer tissues.

The expression of genes coding for inflammatory cytokine interleukin-1-alpha (IL-1 alpha), IL-6, interferon-gamma and tumor necrosis factor-alpha from 15 normal cervix, 11 cervical intraepithelial neoplasia and 13 cervical cancer tissues was investigated. The cytokine messenger ribonucleic acids were reverse transcribed and amplified in the presence of biotinylated and dinitrophenylated primers. Amplified DNA was then captured onto streptavidin-coated microwell plate and quantitatively measured in a colorimetric reaction using ant-DNP antibodies conjugated to horse radish peroxidase. There is no change of IL-1 alpha, IL-6 and tumor necrosis factor-alpha gene expression in either cervical intraepithelial neoplasia or cervical cancer tissues. But the transcription of interferon-gamma gene is significantly reduced in both cervical intraepithelial neoplasia and cervical cancer tissue as compared to normal cervix. This study demonstrated that reverse transcription and quantitative polymerase chain reaction coupling to colorimetric microwell plate assay is a sensitive and useful method to quantitate multiple cytokine gene expression. Our results also suggest that cervical epithelial cells are capable to express cytokines and that interferon-gamma may play a role in the pathogenesis of cervical cancer since its reduced expression may influence inflammation and immunity of the cervical tissues.

Base Sequence↗
PubMed1994

Presence of cells of fetal origin in maternal circulation of pregnant women.

Fetal cells can be identified by using the polymerase chain reaction to test for the presence of human Y-chromosome-specific ZFY and SRY gene DNA sequences in maternal peripheral blood of women who bear a male fetus. Thirty-one pregnant women were studied in the first trimester to determine when fetal cells become detectable in the maternal circulation. Among the 19 women whose peripheral blood samples were positive for Y-chromosome-specific DNA sequences, the presence of fetal cells was quite case-variable from the 6th to 12th gestational weeks. Twenty-eight women who had given birth to their first male babies were studied postpartum to determine when fetal cells disappear from the maternal circulation. Fetal cells can still be detected in maternal blood 10 months postpartum in some cases. These results suggest that identification of fetal cells in the maternal circulation is possible. Nevertheless, interpretation of fetal cells in maternal circulation should be handled very carefully with respect to when these fetal cells first became detectable and potential interference from previous pregnancies.

DNA-Binding Proteins↗
PubMed1994

State of mutational alterations of p53 and retinoblastoma susceptibility genes in papillomavirus-negative small cell cervical carcinomas.

Genetic aberrations were examined to assess the possible roles that p53 and retinoblastoma susceptibility genes might have played in the development of small cell cervical carcinomas. Cervical cancer tissues from 12 patients with small cell cervical carcinoma that were free of human papillomavirus were analyzed. The presence of mutational alterations were examined by polymerase chain reaction-single-strand conformation polymorphism and by direct DNA sequencing. None of 12 small cell cervical carcinomas were found to contain mutations in regions of p53 and retinoblastoma susceptibility genes that were functionally important and where most mutations, in human tumors have been found. Furthermore, there was no evidence indicative of loss of heterozygosity of chromosome region 17p13 (in which p53 is located) in these tumors. These data seem to suggest that whereas mutant type of p53 and retinoblastoma susceptibility genes may exhibit "oncogenic" function in many human tumors, mutational inactivation of these genes may not be an important feature in the carcinogenic development of human papillomavirus-negative small cell cervical carcinomas.

Base Sequence↗
PubMed1994

Genital human papillomavirus infections in young women with vulvar and vestibular papillomatosis.

Possible involvement of human papillomaviruses (HPV) in the development of vulvar and vestibular papillomatosis was investigated by using PCR to determine whether HPV DNA was present in lesions. Fourteen of 272 (5.1%) young women studied were found on gross and histological examination to have vulvar or vestibular papillomatosis. HPV DNA sequences were detected in cervicovaginal lavage specimens of 2 of 14 (14.3%) papillomatosis patients and 1 of 17 (5.9%) matched individuals in the control group without lesions. The difference in HPV prevalence between these two groups was not statistically significant (x2 = 0.51, p > 0.2). Furthermore, none of the 14 vulvar or vestibular papillomatosis biopsy tissues contained HPV DNA. The results suggest that vulvar and vestibular papillomatosis has an etiology other than HPV infection.

Adolescent↗
PubMed1994

Prevalence of human papillomavirus DNA sequences in an area with very high incidence of cervical carcinoma.

To improve our understanding of the relationship and possible associations between human papillomavirus (HPV) infection and the development of cervical malignancies, the presence of multiple types of HPV DNA sequences in cervical carcinoma was determined in Chinese citizens living in two different geographical locations where the incidences of cervical carcinoma are either relatively low or extremely high. HPV DNA sequences were found in 88.5% (54 of 61) of Chinese cervical carcinoma patients living in Taiwan, where the prevalence of cervical carcinoma is 23.7 per 100,000 women. In contrast, in LueYang in Shanxi province, an area with a very high prevalence of cervical carcinoma (1,026 per 100,000 women), only 57.1% (28 of 49) of Chinese cervical carcinoma patients were found to be infected with genital HPV. This result seems to suggest that either the presence of HPV may have different implications in different populations or HPV infection may not be the only factor that determines the development of cervical carcinoma, at least in certain geographical areas. Recently acquired transient or chronic persistent HPV infection may have a different outcome with regard to cervical carcinogenesis. Alternatively, other factors, such as host determinants, may play a role in the development of cervical carcinoma.

Age Factors↗
PubMed1994

Detection of human papillomavirus RNA in ovarian and endometrial carcinomas by reverse transcription/polymerase chain reaction.

The presence of human papillomavirus (HPV) type 16 and 18 transcripts was determined by reverse transcription/polymerase chain reaction (PCR) in ovarian and endometrial carcinoma tissue. HPV-16 DNA sequences were detected in 50.0% (9/18) of the ovarian carcinomas and in 44.4% (8/18) of endometrial carcinomas. HPV-18 DNA sequences were found in 16.7% (3/18) of both the ovarian and endometrial carcinomas. Using RNA-PCR analysis, we found 3 out of 9 (33.3%) of the HPV-16 DNA-positive and 1 in 3 (33.3%) of the HPV-18 DNA-positive ovarian carcinomas were transcriptionally active, contrary to the HPV-16 DNA-positive or HPV-18 DNA-positive endometrial carcinomas. The results suggest that HPV RNA may be detected in ovarian carcinomas though its biological significance remains to be elucidated. HPV RNA is not demonstrable in endometrial carcinoma using the current primer sets. Further investigations are necessary for a final conclusion.

Adult↗
PubMed1993

Fetal cells in the maternal circulation during first trimester in pregnancies.

To investigate the presence of fetal cells in the maternal circulation during early pregnancy, the polymerase chain reaction was used to test the presence of human Y chromosome-specific ZFY and SRY gene DNA sequences in maternal peripheral blood specimens from 19 women carrying male fetuses and 12 women carrying female fetuses. The presence of fetal cells was suggested as early as 6 weeks gestation in 1 of the 19 women bearing male fetuses. Fetal cells were present in the maternal circulation of 15 of the 19 women by 9 weeks gestation, and in only 1 of the 19 were fetal cells not detected until the 12th week after conception. These results suggest that identification of fetal cells in the maternal circulation is possible with a properly designed and executed polymerase chain reaction. However, there was considerable variation with respect to when these fetal cells first became detectable during pregnancy. These fetal cells are potentially a valuable source of material for biochemical and genetic studies of the fetuses.

Base Sequence↗
PubMed1993

Detection of beta-thalassemia carrier by direct analysis of beta-globin gene lesions.

DNA was prepared from peripheral blood mononuclear cells of 114 Chinese with low erythrocyte mean corpuscular volume and analyzed by allele-specific DNA amplification for the presence of mutant alleles in the beta-globin gene that account for about 90% of beta-thalassemia in Chinese. A total of 9 mutations of the five most frequent mutant alleles were detected in 8 individuals. All mutant sequences were confirmed later by DNA sequencing. However, no mutation of these mutant alleles was detected in the remaining 106 individuals with low erythrocyte mean corpuscular volume including 22 who also had Hb A2 content of 6.0% or more. Our results seem to suggest that the presence of beta-thalassemia allele does not correlate very well with red blood cell indices and that direct DNA analysis by allele-specific DNA amplification is an accurate method to identify beta-thalassemia heterozygotes.

Alleles↗
PubMed1993

Inhibition of in vitro enzymatic DNA amplification reaction by ultra-violet light irradiation.

Ultra-violet light irradiation of containers and components used in in vitro DNA amplification reactions catalyse by Taq DNA polymerase is a simple and effective method to reduce carry-over contamination and can reduce false-positive results. However, we found that prolonged exposure of water in polypropylene microcentrifuge tubes to u.v. light can result in reduction of amplification efficiency by at least two orders of magnitude when these water specimens are used in amplification reaction mixtures. Although the mechanism that causes this inhibition of DNA amplification is unclear now, the results seem to suggest that u.v. irradiation for routine anti-contamination purposes should be used with caution.

Centrifugation↗
PubMed1993

Possible non-sexual transmission of genital human papillomavirus infections in young women.

Human papillomaviruses were detected by an in vitro enzymatic DNA amplification method in cells obtained from vulvar swabs of 9 of 61 (14.8%) young women without prior experience of sexual intercourse and in 7 of 57 (12.3%) young women with prior experience. The prevalence of human papillomavirus DNA in these two groups of women was not significantly different (x2 = 0.16, p > 0.5; 95% confidence interval -0.165 to 0.215). These results suggest that genital human papillomavirus is not sexually transmitted in all cases and that it may be acquired by modes other than sexual contact.

Adult↗
PubMed1993

Lack of mutational alteration in the conserved regions of ZFY and SRY genes of 46,XY females with gonadal dysgenesis.

To further our understanding of the mechanism of action of regulatory and structural genes involved in human sex determination, we have examined three sex-reversed 46,XY females and two of their normal fathers for any mutational alteration in ZFY and SRY genes, using polymerase chain reaction and single-strand conformation polymorphism and by subsequent DNA sequencing. We could not find any mutation in the ZFY and SRY genes of these patients and their fathers. The results seem to suggest that although ZFY and SRY may be required for initiation of testis differentiation and male sex determination, sex-reversed females may predominantly result from alterations in genes either downstream or secondary to ZFY or SRY.

Base Sequence↗
PubMed1992

Prevalence of genital human papillomavirus infections in patients at a sexually transmitted diseases clinic.

The human papillomavirus was detected in cervicovaginal cells by the polymerase chain reaction in 14 of 37 (37.8%) patients attending a sexually transmitted disease (STD) clinic and in 6 of 43 healthy young women (14.0%) undergoing routine gynecologic examinations who served as controls. The results indicated that even the more malignant types of human papillomaviruses were not uncommon among the control group, and that the prevalence of human papillomavirus infection was significantly higher in STD clinic patients than in the control group. These findings confirm the suggestion that factors other than human papillomavirus infections may be involved in the pathogenesis of cervical cancer.

Ambulatory Care Facilities↗
PubMed1992

Analysis of peripheral blood of pregnant women for the presence of fetal Y chromosome-specific ZFY gene deoxyribonucleic acid sequences.

Deoxyribonucleic acid sequences of human ZFY (zinc-finger-Y) gene, a Y-chromosome-specific gene and candidate for the testis-determining factor, has been identified by an in vitro enzymatic deoxyribonucleic acid amplification method in peripheral blood specimens of women pregnant with male fetuses. This technique permits detection of ZFY gene deoxyribonucleic acid sequences in as few as a single male cell among 1,000,000 female cells. Maternal blood results were confirmed by amplification of ZFY gene deoxyribonucleic acid sequences in chorionic villus cells and by karyotyping in 33 of 36 pregnant women. There was no false-positive male result, and two of the three blood specimens with false-negative results were obtained from pregnant women at a very early gestational age. With properly designed guidelines, this deoxyribonucleic acid amplification method may be an alternative to determine the fetal sex for those pregnancies at risk for X-linked genetic disorders.

Base Sequence↗
PubMed1992

Possible transplacental transmission of human papillomaviruses.

OBJECTIVE: The objective of this study was to examine the possibility of intrauterine human papillomavirus infection of fetuses by transplacental transmission of human papillomavirus before delivery. STUDY DESIGN: Specimens of cervicovaginal cells and peripheral blood mononuclear cells were obtained from 52 consecutive pregnant women in the third trimester of pregnancy. Cord blood specimens were also obtained from the neonates born to these mothers. Presence of human papillomavirus types 16 and 18 deoxyribonucleic acid was analyzed by an in vitro enzymatic deoxyribonucleic acid amplification method. RESULTS: Human papillomavirus type 16 deoxyribonucleic acid was found in 6 (11.5%) cervicovaginal and in 9 (17.3%) peripheral blood mononuclear cell specimens. Seven cord blood specimens from neonates born to mothers who were positive for peripheral blood mononuclear cell human papillomavirus type 16 deoxyribonucleic acid were found to contain human papillomavirus type 16 deoxyribonucleic acid. One cervicovaginal and two peripheral blood mononuclear cell specimens contained human papillomavirus type 18 deoxyribonucleic acid, but none of the cord blood specimens contained human papillomavirus type 18 deoxyribonucleic acid. CONCLUSION: These results seem to suggest possible transplacental transmission of the virus and the potential association of such transmission with the status of human papillomavirus in peripheral blood mononuclear cells.

Base Sequence↗