F. De Seta

Aetiology of preterm labour: bacterial vaginosis

Bacterial vaginosis (BV) is a common condition characterised by a polymicrobial disorder, with an overgrowth of several anaerobic or facultative bacteria and with a reduction or absence of lactobacillus colonisation. The prevalence of BV ranges from 4 to 64%, depending on the racial, geographic and clinical characteristics of the study population. In asymptomatic women, the prevalence varies from 12 to 25%, and similar percentages are observed in pregnant women. Although BV is associated with several adverse outcomes, such as upper genital tract infections, pelvic inflammatory disease, endometritis, preterm birth and low birthweight, many basic questions regarding the pathogenesis of BV remain unanswered. Mucosal immune system activation may represent a critical determinant of adverse consequences associated with BV. An unequal risk for BV acquisition and\or recurrence could derive from different mucosal immune host abilities and\or capability of invading microbes to produce factors that inactivate the local immune response. BV is associated with a two‐fold increased risk of preterm birth, with the greatest risk when BV is present before 16 weeks of gestation (odds ratio = 7.55). This may indicate a critical period during early gestation when BV‐related organisms can gain access to the upper genital tract and set the stage for spontaneous preterm labour later in gestation. The results of treatment trials for pregnant women with BV have been heterogeneous, with anywhere from an 80% reduction to a two‐fold increase in preterm birth among women who received treatment. For this reason, in current clinical practice significant controversy surrounds determining not only who and when to screen but also who and how to treat. Recent evidence shows that individual genetic backgrounds can affect chemokine production. This is an interesting area for future research and could lead to trials of treatment only for women genetically predisposed to preterm birth.

Update on Chlamydia trachomatis

Abstract: Chlamydia trachomatis is one the most important sexually transmitted diseases; it can cause serious sequelae despite the absence of symptoms in some people. Its estimated that about 25% of women who have acute salpingitis become infertile, and chlamydial infection is the commonest cause. The introduction of screening programs for its detection are still a topic of discussion. The literature shows that the total cost of examination and treatment of complications known to be associated with genital chlamydial infection (PID, chronic pelvic pain, tubal factor infertility) is generally higher than the total cost of a large‐scale Chlamydia screening program. The selection of a diagnostic test for detection of chlamydial genital infection depends on availability, local expertise, and prevalence of Chlamydia trachomatis in the test population. Cell culture is too expensive in nonendemic regions, so the use of non‐culture techniques is very attractive. PCR (polymerase chain reaction) and LCR (ligase chain reaction) are actually the two most commonly used alternatives to conventional methods for detecting STD agents. In fact, PCR and LCR have proved useful for detection of Chlamydia trachomatis in cervical and urethral samples both in symptomatic and asymptomatic women. Recently, testing of first‐void urine (FVU) specimens with these techniques has shown that the amplification tests are as sensitive as tests with endocervical swab cultures.

Mannose-binding lectin is produced by vaginal epithelial cells and its level in the vaginal fluid is influenced by progesterone.

Mannose-binding lectin (MBL) is a recognition molecule of the complement (C) system and binds to carbohydrate ligands present on a wide range of pathogenic bacteria, viruses, fungi, and parasites. MBL has been detected in the cervico-vaginal cavity where it can provide a first-line defence against infectious agents colonizing the lower tract of the reproductive system. Analysis of the cervico-vaginal lavage (CVL) obtained from 11 normal cycling women at different phases of the menstrual cycle revealed increased levels of MBL in the secretive phase. Part of this MBL derives from the circulation as indicated by the presence of transferrin in CVL tested as a marker of vascular and tissue permeability. The local synthesis of MBL is suggested by the finding that its level is substantially higher than that of transferrin in the secretive phase. The contribution of endometrium is negligible since the MBL level did not change before and after hysterectomy. RT-PCR and in situ RT-PCR analysis showed that the vaginal tissue, and in particular the basal layer of the epithelium, is a source of MBL which binds to the basal membrane and to cells of the outer layers of the epithelium. In conclusion, we have shown that MBL detected in CVL derives both from plasma as result of transudation and from local synthesis and its level is progesterone dependent increasing in the secretive phase of the menstrual cycle.

Quantitative in situ detection of high-risk human papillomavirus in cytological specimens by SYBR Green I fluorescent labeling

Abstract In this study we developed an in situ protocol for quantitative detection of high-risk human papillomavirus (HPV), based on direct in situ polymerase chain reaction (PCR) with SYBR Green I labeling and GeneAmp 5700 Sequence Detection System technology. This protocol was applied on cytological specimens of patients with cervical intraepithelial neoplasia (CIN) and squamous cell carcinoma (SCC). We performed direct in situ quantitative PCR on cell smears, uninfected human skin fibroblasts, Hela and Caski cells. After in situ amplification, slides were counterstained with propodium iodide and analyzed under a fluorescent microscope in order to localize high-risk HPV and verify preservation of morphology. After PCR optimization, we obtained the following results. The Hela cells showed values ranging from 15 to 33 copies of high-risk HPV per cell, the Caski cell line from 220 to 300 high-risk HPV copies per cell and the cell smear (both CIN and SCC) around 20–35 copies of high-risk HPV per cell. No high-risk HPV amplification was detected in uninfected human fibroblasts, healthy controls, non-amplification control, and non-specific primer control. A positive intranuclear high-risk HPV amplification was detected in cell smears from 20 patients with CIN and 10 with SCC. In conclusion, our in situ quantitative protocol for high-risk HPV detection on cell smears combines both quantitative data and in situ localization of the target, with preservation of morphology. For this reason it could be used as a rapid screening tool when both morphological and quantitative results are requested on the same slide.