Chlamydia trachomatis infection in prelabour amniorrhexis

The prevalence of Chlamydia trachomatis in the lower genital tract and amniotic fluid of women with preterm prelabour amniorrhexis was assessed by DNA amplification for C. trachomatis performed in cervical swabs and amniotic fluid obtained by amniocentesis. C. trachomatis was present in the cervix of 20 (23%) of the cases and in six (30%) of those the organism was also present in the amniotic fluid. There was no association with other pathogens in the lower genital tract or amniotic fluid. The presence of C. trachomatis was not associated with a significant decrease in the amniorrhexis to delivery interval or with an increase in perinatal mortality or morbidity.     

Bacterial and mammalian DNA alkyltransferases sensitize Escherichia coli to the lethal and mutagenic effects of dibromoalkanes

Here we confirm and extend our previous studies demonstrating that the mutagenic potency of 1,2-dibromoethane (DBE) and dibromomethane (DBM) is markedly enhanced (not prevented) in bacteria expressing the O6- alkylguanine-DNA alkyltransferase (ATase) encoded by the Escherichia coli ogt gene. We demonstrate that, in close parallel with mutagenesis, the Ogt ATase sensitizes the bacteria to the lethal effects of these carcinogens, suggesting that one or more of the potentially mutagenic lesions induced by DBE and DBM in the presence of Ogt has additional lethal capacity. We further demonstrate that the sensitization to both lethality and mutagenesis by DBE and DBM is a property shared by other DNA alkyltransferases. This objective was accomplished by quantifying the induction of mutations and lethal events in ogt- ada- E. coli expressing an exogenous bacterial or mammalian ATase from a multicopy plasmid. Mammalian recombinant ATases enhanced the lethal and mutagenic actions of DBE and suppressed the lack of sensitivity of the vector- transformed bacteria to DBM. In most cases the order of effectiveness of the ATases ranked: murine > human > Ogt > rat. Further comparisons included the full-length Ada ATase from E. coli and a truncated Ada version (T-ada) that retains the O6-methylguanine binding domain of the protein. The full-length Ada ATase was effective in enhancing the lethality but not the mutagenicity induced by DBE and DBM. The T-ada ATase provided less sensitization than Ada to lethality by DBE, but of the three bacterial ATases T-ada yielded the highest sensitization to mutagenesis by this compound. T-ada and Ada ATases were in general less effective than the mammalian versions, with the exception of the rat recombinant ATase. The effectiveness of the different mammalian and bacterial ATases in promoting the deleterious actions of dibromoalkanes was compared with the effectiveness of these proteins in suppressing the lethal and mutagenic effects induced by N-nitroso-N-methylurea. The ability to sensitize E. coli to the lethal and mutagenic effects of DBE and DBM seems restricted to DNA alkyltransferase, since overexpression of thioredoxin (Trx) or glutaredoxin (Grx1) in ogt- ada- cells showed no effect, in spite of the reported potential of bioactive dihaloethane- derived species to alkylate Trx.      

Assessment of the mutagenicity of dichloroacetic acid in lacI transgenic B6C3F1 mouse liver

Dichloroacetic acid (DCA) is a chlorination byproduct found in finished drinking water. When administered in drinking water this chemical has been shown to produce hepatocellular adenomas and carcinomas in B6C3F1 mice over the animal's lifetime. In this study, we investigated whether mutant frequencies were increased in mouse liver using treatment protocols that yielded significant tumor induction. DCA was administered continuously at either 1.0 or 3.5 g/l in drinking water to male transgenic B6C3F1 mice harboring the bacterial lacI gene. Groups of five or six animals were killed at 4, 10 or 60 weeks and livers removed. At both 4 and 10 weeks of treatment, there was no significant difference in mutant frequency between the treated and control animals at either dose level. At 60 weeks, mice treated with 1.0 g/l DCA showed a 1.3-fold increase in mutant frequency over concurrent controls (P = 0.05). Mice treated with 3.5 g/l DCA for 60 weeks had a 2.3-fold increase in mutant frequency over the concurrent controls (P = 0.002). The mutation spectrum recovered from mice treated with 3.5 g/l DCA for 60 weeks contained G:C-->A:T transitions (32.79%) and G:C-->T:A transversions (21.31%). In contrast, G:C-->A:T transitions comprised 53.19% of the recovered mutants among control animals. Although only 19.15% of mutations among the controls were at T:A sites, 32.79% of the mutations from DCA-treated animals were at T:A sites. This is consistent with the previous observation that the proportion of mutations at T:A sites in codon 61 of the H-ras gene was increased in DCA-induced liver tumors in B6C3F1 mice. The present study demonstrates DCA-associated mutagenicity in the mouse liver under conditions in which DCA produces hepatic tumors.      

Patterns of treatment of patients with prostate cancer initially managed with surveillance: results from The CaPSURE database. Cancer of the Prostate Strategic Urological Research Endeavor

PURPOSE: We determined the demographic and clinical profile of men who elect surveillance as the initial management of prostate cancer as well as the incidence and predictors of secondary treatment of these patients. MATERIALS AND METHODS: The Cancer of the Prostate Strategic Urological Research Endeavor (CaPSURE) is a national disease registry of patients with various stages and treatments of prostate cancer. Using this database of 4,458 men we identified 329 (8.2%) who elected surveillance as the initial management of prostate cancer. Patients choosing watchful waiting were compared to other CaPSURE participants using the chi-square test. The likelihood of treatment initiation in the watchful waiting group was calculated using the Kaplan-Meier method. After adjusting for patient age, race, prostate specific antigen (PSA) at diagnosis, clinical T stage and total Gleason score the Cox proportional hazards regression model was used to determine significant predictors of treatment initiation. RESULTS: Compared with others in the database, patients on watchful waiting were more likely to be 75 years old or older (51% versus 16%, p <0.001), white (93% versus 85%, p <0.001), and have lower serum PSA (p <0.001), organ confined disease (97% versus 88%, p <0.001) and a total Gleason score of 7 or less (97% versus 88%, p <0.001). In the watchful waiting group there was a 52% likelihood of treatment initiation within 5 years of the diagnosis. Significant predictors of secondary treatment were age younger than 65 years and elevated serum PSA at diagnosis. Neither race, extraprostatic stage cT3 disease nor higher total Gleason score was a significant predictor of treatment. CONCLUSIONS: Men who elect initial watchful waiting for prostate cancer tend to be older, have lower serum PSA and more favorable disease characteristics than those who seek treatment. PSA at diagnosis is the dominant factor for predicting secondary treatment.