BackgroundPreterm premature rupture of membranes (PPROM) complicates 1 % of all pregnancies and occurs in one third of all preterm deliveries. Midtrimester PPROM is often followed by spontaneous miscarriage and elective termination of ongoing pregnancies is offered in many countries. The aim of this retrospective descriptive cohort study was to investigate the natural history of midtrimester PPROM in a jurisdiction where termination of pregnancy in the absence of maternal compromise is unavailable.MethodsCases of midtrimester PPROM diagnosed between 14 and 23 + 6 weeks’ gestation during April 2007 to June 2012 were identified following a manual search of all birth registers, pregnancy loss registers, annual reports, ultrasound reports, emergency room registers and neonatal death certificates at Cork University Maternity Hospital - a large (circa 8500 births per annum) tertiary referral maternity hospital in southwest Ireland. Cases where delivery occurred within 24 h of PPROM were excluded.ResultsThe prevalence of midtrimester PPROM was 0.1 % (42 cases/44,667 births). The mean gestation at PPROM was 18 weeks. The mean gestation at delivery was 20 + 5 weeks, with an average latency period of 13 days.Ten infants were born alive (23 %; 10/42). The remainder (77 %; 32/42) died in utero or intrapartum. Nine infants were resuscitated. Two infants survived to discharge. The overall mortality rate was 95 % (40/42).Five women had clinical chorioamnionitis (12 %; 5/42) but 69 % demonstrated histological chorioamnionitis. One woman developed sepsis (2.4 %; 1/42). Other maternal complications included requirement of intravenous antibiotic treatment (38 %; 17/42), retained placenta (21 %, 9/42) and post-partum haemorrhage (12 %; 5/42).ConclusionsThis study provides useful and contemporary data on midtrimester PPROM. Whilst fetal and neonatal mortality is high, long-term survival is not impossible. The increased risk of maternal morbidity necessitates close surveillance.Electronic supplementary materialThe online version of this article (doi:10.1186/s12884-016-0813-3) contains supplementary material, which is available to authorized users.

Previous reports from this laboratory indicate that cultured simian virus 40 (SV40)-transformed human keratinocytes express keratin proteins characteristic of simple epithelia that are not found in their untransformed counterparts. In this study we show by in vitro translation and RNA transfer blot analysis that the altered keratin synthesis reflects changes in the abundance of specific keratin mRNAs. SV40-transformed keratinocytes have a reduced abundance of transcripts for 58-, 56-, 52-, 50-, 48-, and 46-kDa keratin species, compared with uninfected cultured keratinocytes, but express significant levels of transcripts for 52-, 45-, and 40-kDa keratins, typical of simple epithelia. The SV40-transformed cells also express mRNA for a 48-kDa keratin that is unique to SV40-transformed keratinocytes. Analysis of the keratin genome with keratin-specific cDNAs as probes indicates that the changes in keratin transcription are not correlated with gross rearrangements of the keratin genome. These results suggest that analysis of viral transformation of cultured keratinocytes affords a novel approach to study mechanisms regulating keratin gene expression. (9)(10)(11). This expression pattern and in vitro assembly experiments suggest that one member from each family is required for filament assembly (12). In addition, studies using keratin-specific cDNAs have shown that each keratin subfamily is encoded by genes from a distinct keratin multigene family (10,13,14).Cultured human keratinocytes characteristically express keratins of 58, 56, 50, and 46 kDa in high abundance and keratins of 52, 48, and 40 kDa in lower abundance (15,16). Transformation of cultured keratinocytes by SV40 disrupts this normally stable pattern of keratin synthesis and induces the synthesis of keratins characteristic of simple epithelia (6-8). In the present study we have investigated the alteration of keratin expression in SV40-transformed keratinocytes by analyzing the expression and structural arrangement of the keratin genes using keratin-specific cDNAs as probes. These studies indicate that regulation of the changes in keratin protein synthesis in SV40-transformed cell lines is probably at the transcriptional level in the absence of major alterations in the structure of keratin genes. MATERIALS AND METHODSCulture conditions for human keratinocytes derived from neonatal foreskin, SV40-transformed keratinocyte cell lines, and a squamous cell carcinoma (SCC) cell line have been described elsewhere (8).Isolation of Total Cellular RNA and Poly(A)+ RNA. Total cellular RNA and poly(A)+ RNA were prepared essentially as described (17).Preparation of Genomic DNA. High molecular weight DNA was purified as described (18).Gel Electrophoresis and Transfer to Nitrocellulose of DNA and RNA. After digestion with various restriction enzymes under conditions recommended by the supplier, DNA fragments were separated by electrophoresis through 1% agarose (Bethesda Research Laboratories) gels containing Tris acetate buffer (0.04 M Tris acetate, pH 8.0/2 mM E...

SUMMARYChinese hamster kidney cells are semi-permissive to simian virus 40 (SV4o). Exposure to mitomycin C (MC) of Chinese hamster kidney cells infected with SV4o DNA enhanced the yield of infectious virus Io-to zoo-fold. This stimulation occurred whether the treatment was performed before or after infection. A simultaneous increase in the number of V antigen-synthesizing cells and virus-producing cells, as well as the virus burst size, was observed upon MC pretreatment, whereas the proportion of T antigen-synthesizing cells remained unchanged. MC pretreatment clearly stimulated virus DNA replication in SV4o virus-infected cells. Cells treated with MC exhibited an unbalanced growth pattern, with continuing protein synthesis in the absence of cell division and a markedly reduced ability to replicate the cellular DNA. These results suggest that MC enhances the permissiveness of Chinese hamster kidney cells by inducing the synthesis of a specific cellular factor(s) required for SV4o replication in these cells. Exposure to ultraviolet light also enhanced infectious virus production in Chinese hamster kidney cells.

SUMMARYTreatment of a fully permissive monkey kidney cell clone (CV1Cll) with 5-iodoz'-deoxyuridine (IdUrd) before infection with SV4o virus enhances the yield of virions 1o-to 5o-fold. The increase is detectable only after slowing down the virus growth cycle by reducing the m.o.i, and by incubating at low temperature. The IdUrd pre-treatment enhances SV4o DNA replication and the number of Vantigen and virus-synthesizing cells. The potentiating effect of IdUrd is not observed when the pre-treated cells are infected with SV4o DNA. The synthesis of SV4o T-antigen is increased even in the presence of cytosine arabinoside (Ara-C). IdUrd inhibits cellular DNA synthesis but the incorporation of 3H-uridine and 3H-leucine into RNA and proteins is not affected. Late virus functions are preferentially expressed in the cells in which cellular DNA synthesis is inhibited. The results suggest that the enhancement by IdUrd of SV4o replication would be the consequence of at least two complementary events: (0 stimulation of an early virus function localized between the arrival of the virus DNA in the nucleus and T-antigen induction; (2) inhibition of cellular DNA synthesis with a consequent greater availability of cellular factors required for virus growth.