The in situ polymerase chain reaction for detection of chlamydia trachomatis

Chlamydia trachomatis and Neisseria gonorrhoeae PCR detection in women treated for ectopic pregnancy

The aim of this study was to determine the presence of Chlamydia trachomatis (ChT) and Neisseria gonorrhoae (NG) in the genital tract of women with ectopic pregnancy and to compare the positive results with patients' self-reported history of PID. Overall 40 women were eligible for the study. The samples for the ChT and NG Polymerase Chain-reaction (PCR) detection were obtained from the cervix, endometrium and fallopian tube. The results of testing for NG at all sites were negative as were the results from cervical testing for ChT. The prevalence of ChT in the upper genital tract was 12.5%. No statistically significant correlation was found between the positive cases and the previous signs of PID and laparoscopic findings. We found statistically significant relationship between signs of pelvic inflammation in a pacients' history and histopathological findings of tubal inflammation. 12.5% prevalence of ChT confirms the ascending genital infection. There was no association between the positive PCR result and clinical history of pelvic inflammation.IMPACT STATEMENTWhat is already known on this subject? Pelvic inflammatory disease, Chlamydia trachomatis and Neisseria gonorrhoae infections are the main risks for ectopic pregnancy. Clinical history of PID and perioperative adhesions may suggest prior upper genital infection.What do the results of this study add? Chlamydia trachomatis positive PCR result can be found in the upper genital tract without the positivity of cervical smear in women with ectopic pregnancy. Our study is unique in assessing the endometrial biopsy for the presence of Chlamydia trachomatis and Neisseria gonorrhoae.What are the implications of these findings for future clinical practice and/or future clinical research? There is no statistically significant association between positive PCR result and clinical history of PID or pelvic adhesions found during laparoscopy for tubal pregnancy. Therefore there is no need for the preventive antibiotic treatment in patients with these findings.

Interactions between human papillomavirus and other sexually transmitted agents in the etiology of cervical cancer

The interplay between human papillomavirus, notably type 16, and HIV in cervical carcinogenesis leads to persistent infection and cervical neoplasia by destruction of the afferent arm (Langerhans cells) of the host immune system. The joint effect takes place at the early stages of squamous intraepithelial lesions and has severe consequences if left untreated. The recent increase of cervical cancer mortality in young women in developed countries may well be a result of the HIV epidemic. Infection with Chlamydia trachomatis is associated with cervical squamous cell carcinoma but not with cervical adenocarcinoma, and the association remains after adjusting for human papillomavirus 16. Joint effects of C. trachomatis and the human papillomaviruses have not been studied at the population level but indirect evidence from epidemiological studies suggests that the interaction might be different (synergistic versus antagonistic) at different stages (cervical intraepithelial neoplasia versus invasive cervical cancer) of cervical carcino-genesis. Concomitant exposure to human papillomaviruses 6 or 11 and human papillomavirus type 16 has not been shown to result in excess risk of cervical squamous cell carcinoma. This antagonistic joint effect was also discovered between human papillomavirus types 18 and 16, as well as 33 and 16. Herpes simplex virus type 2 antibodies are associated with a modest risk of cervical cancer, which is not surprising since the presence of herpes simplex virus antibodies reflects risk-taking sexual behaviour. However, no excess risk remains after adjustment for human papillomavirus type 16, and no interaction between these two viruses has been found in epidemiological studies. Evidence of interaction between human papillomavirus type 16 and the other members of the herpesvirus family is still at an experimental level and difficult to judge. Little progress has been made in the most promising experimental association between the oncogenic human papillomaviruses and adeno-associated viruses. In addition to the well established interaction between human papillomaviruses and HIV, intriguing interactions are emerging between the human papillomaviruses and C. trachomatis, as well as between the different human papillomavirus types.

Chlamydia trachomatis modulates expression of tumor suppressor gene caveolin-1 and oncogene C-myc in the transformation zone of non-neoplastic cervical tissue

OBJECTIVES

The obligate intracellular bacterium Chlamydia trachomatis is frequently found in association with benign proliferative, pre-neoplastic and malignant changes in cervical epithelium. The present study addresses the possible role of C. trachomatis infection of the uterine cervix in modulating human cancer gene expression.

METHODS

RNA was extracted from both C. trachomatis infected and non-infected human fibroblast cultures treated with ITFgamma. The extracted RNA was used for cDNA microarrays carrying 33,000 human genes to detect abnormal gene expression induced by Chlamydia. Forty specimens of cervix dissected from the transformation zone had previously tested negative for HPV and positive for C. trachomatis by standard DNA PCR (20). These samples were subjected to RT-PCR to detect the expression of the abnormal genes induced by Chlamydia infection.

RESULTS

The ITFgamma-induced, non-replicative Chlamydia-infected fibroblast cultures showed significant modulation of gene expression. The cultures showed a 2-fold decrease in the expression of the gene coding for the tumor suppressor caveolin-1, and increased expression of the oncogene C-myc, a promoter of cervical carcinogenesis. In tissues from the Chlamydia-infected cervical transformation zone, real-time RT-PCR demonstrated a highly significant average 4.7-fold reduction of caveolin-1 mRNA (P < or = 0.0001) and an average 2.1-fold increase in C-myc (P < 0.05).

CONCLUSIONS

Human ITFgamma-treated fibroblasts as well as non-neoplastic cervical tissues responded to C. trachomatis with a strong down-regulation of caveolin-1 mRNA and a light up-regulation of C-myc mRNA. These changes were independent of the HPV high-risk types. This study reveals possible mechanisms by which C. trachomatis infection may contribute to neoplastic changes in the transformation of uterine cervix. These possible mechanisms require further evaluation.

Cervicovaginal coinfections with human papillomavirus and Chlamydia trachomatis

Human papillomavirus (HPV) and Chlamydia trachomatis (CT) are the two most common sexually transmitted pathogens, and infection with either reportedly was associated with cervical intraepithelial neoplasia (CIN) in women. In view of their similar mode of transmission, CT infection was examined as a possible HPV cofactor in the etiology of CIN disease. In total, 129 women were included in the study, of whom 80 were negative (mean age 34.17 +/- 6.9) and 49 were positive (mean age 33.16 +/- 6.8) for HPV DNA (assessed by PCR). CT DNA was determined in endocervical and first-catch urine specimens by PCR. Whereas HPV-positive and HPV-negative women were similar with respect to age (p = 0.419) and pregnancy outcomes (p = 0.628), the number of smokers (p = 0.001), women with multiple male sex partners (p = 0.002) or with abnormal cytology (p < 0.001) was higher in the HPV-positive group. There was an increase in CT infection rate in HPV-positive (29/49) as compared to HPV-negative (10/80) women (p < 0.01). Within HPV-positive patients, there was no significant difference between CT-positive and CT-negative patients with regards to the risk factors studied. Collectively, this suggests that CT infection is a cofactor of HPV in CIN disease development, possibly by modulating the host's immunity and/or precipitation of chronic inflammation.

Localisation of GABA(A) receptor subunits in the CNS using RT-PCR

This paper presents an RT-PCR in situ histochemistry (RT-ISH) method for the detection and localisation of isoforms of the GABA(A) receptor in formalin-fixed, paraffin-embedded brain sections. RT-ISH was performed using PCR conditions already established in our laboratory for the amplification of the alpha(1-3) and beta(1-3) subunits of the GABA(A) receptor [2,5]. Initial experiments determined whether mRNA isolated from such sections was suitable for use in RT-PCR. Transcripts encoding both the alpha- and beta-subunits of the GABA(A) receptor were successfully amplified. RT-ISH, a one-step RT-PCR method, was used to amplify the transcripts and digoxigenin-labeled nucleotides were directly incorporated into the amplified products during cycling. RT-PCR products were detected using anti-digoxigenin antibody conjugated to alkaline-phosphatase and signal was visualised using light microscopy. This protocol may be used to study the expression of GABA(A) receptor isoforms in vivo and examine alterations in receptor composition during development and disease states.