The lux autoinducer regulates the production of exoenzyme virulence determinants in Erwinia carotovora and Pseudomonas aeruginosa

Erwinia carotovora and Pseudomonas aeruginosa secrete exoenzymes that contribute to the pathogenesis of plant and mammalian infections respectively. E.carotovora mutants defective in synthesis of the pectinase, cellulase and protease exoenzymes were isolated and classified into two groups. Group 2 mutants were found to be defective in the production of a small freely diffusible molecule, N-3-(oxohexanoyl)-L-homoserine, lactone (HSL), and were avirulent. Addition of exogenous HSL to these group 2 mutants restores synthesis of the exoenzymes and virulence in planta. Of the exoenzymes of P.aeruginosa the metalloprotease, elastase, is an established virulence determinant. Mutants of P.aeruginosa that are defective in elastase production have been isolated and were again found to fall into two groups. Analogous to the group 2 mutants of E.carotovora, group 2 mutants of P. aeruginosa are defective in the synthesis of HSL and exogenous HSL restores elastase production. HSL has now been linked to the control of bioluminescence in Vibrio fischeri, carbapenem antibiotic production of E.carotovora and the above exoenzyme virulence determinants. This information significantly enhances our understanding of the extent and nature of pheromone mediated gene expression control in prokaryotes.

Does aspirin have a role in improving pregnancy outcome for women with the antiphospholipid syndrome? A randomized controlled trial

OBJECTIVE

This pilot investigation was undertaken to assess the efficacy of low-dose aspirin therapy for the treatment of women with antiphospholipid antibodies when recurrent miscarriage is the only sequela.

STUDY DESIGN

A double-blind, randomized, placebo-controlled trial was conducted in the setting of the recurrent miscarriage clinic of a tertiary referral obstetric hospital. The participants were 50 women with a history of recurrent miscarriages (>/=3) and antiphospholipid antibodies. Women with systemic lupus erythematosus or a history of thrombosis were excluded. Women were recruited after full investigative screening at the recurrent miscarriage clinic. Women with >/=3 fetal losses and persistently positive results for antiphospholipid antibodies were randomly allocated to receive either aspirin (75 mg daily) or placebo. Investigators, clinicians, and patients were blinded to the treatment. Rates of live births, antenatal complications, and delivery and neonatal outcomes were recorded prospectively. Data were compared by chi(2) analysis with Yates' correction, the Fisher exact test, or the Student t test as appropriate.

RESULTS

There were 10 exclusions after random assignment because of inappropriate inclusion. Eighty-five percent of the placebo (17/20) group and 80% of the aspirin-treated group (16/20) were delivered of live infants. This difference was not significant. There were no significant differences in antenatal complications or neonatal morbidity between the groups.

CONCLUSIONS

This preliminary study suggests that low-dose aspirin has no additional benefit when added to supportive care for women for whom recurrent early fetal loss is the only sequela of the antiphospholipid syndrome. This live birth rate with supportive care alone exceeds the published live birth rates for women with antiphospholipid antibody-mediated recurrent fetal loss who were treated with heparin or corticosteroids. This trial, like all other trials in this field, is small, but its results bring into question the need for pharmacologic intervention for women with antiphospholipid syndrome for whom recurrent fetal loss is the only sequela. Our results highlight the need for a large randomized controlled trial to identify the optimal treatment for this group of women and justify the inclusion of a placebo arm in any such trial.

A novel strategy for the isolation of luxI homologues: evidence for the widespread distribution of a LuxR:LuxI superfamily in enteric bacteria

The pheromone N-(3-oxohexanoyl)-L-homoserine lactone (OHHL) regulates expression of bioluminescence in the marine bacterium Vibrio fischeri, the production of carbapenem antibiotic in Erwinia carotovora and exoenzymes in both E. carotovora and Pseudomonas aeruginosa. A characteristic feature of this regulatory mechanism in V. fischeri is that it is cell density-dependent, reflecting the need to accumulate sufficient pheromone to trigger the induction of gene expression. Using a lux plasmid-based bioluminescent sensor for OHHL, pheromone production by E. carotovora, Enterobacter agglomerans, Hafnia alvei, Rahnella aquatilis and Serratia marcescens has been demonstrated and shown also to be cell density-dependent. Production of OHHL implies the presence in these bacteria of a gene equivalent to luxI. Chromosomal banks from all five enteric bacteria have yielded clones capable of eliciting OHHL production when expressed in Escherichia coli. The luxI homologue from both E. carotovora (carI) and E. agglomerans (eagI) were characterized at the DNA sequence level and the deduced protein sequences have only 25% identity with the V. fischeri LuxI. Despite this, carI, eagI and luxI are shown to be biologically equivalent. An insertion mutant of eagI demonstrates that this gene is essential for OHHL production in E. agglomerans.

The prevalence of polycystic ovaries on ultrasound scanning in a population of randomly selected women

Polycystic ovaries (PCO) diagnosed by ultrasound have been commonly reported amongst healthy women. The study aimed to determine the prevalence of PCO in a population of women from the community, and to relate it to clinical and endocrinological data. Twelve hundred women chosen randomly from electoral rolls were invited to take part in the study. Two hundred and fifty five women (21%) who met eligibility criteria greed to participate and 183 women 916%) finally completed the study. Seventy two women did not attend. An ultrasound scan and blood tests were taken on day 5-9 of their menstrual cycles. Data about their menstrual periods and reproductive history was collected. The prevalence of PCO was 21% (39 of 183). No differences existed between women with PCO and normal ovaries with respect to uterine size, body mass index, luteinizing hormone levels, serum hormone binding globulin levels and fertility status. Hirsutism (Ferriman Gallwey score > 7), elevated testosterone levels and irregular menstrual cycles were significantly more frequent amongst women with PCO. Mean ovarian volume was larger in women with PCO irrespective of the use of hormonal contraception. Fifty nine per cent of women with PCO had irregular menstrual cycles or elevated Ferriman Gallwey scores or both. There was no detectable effect of PCO on parity or miscarriage although only 70% of women with PCO had evidence of an adequate ovulation compared to 95% of women with normal ovaries.

Antiphospholipid antibodies in pregnancy

We assessed the relationship between antiphospholipid antibodies and recurrent miscarriage, fetal deaths, and the pregnancy complications--placental abruption, fetal growth retardation and preeclampsia. The subjects were 81 women with a history of 3 or more miscarriages, 62 with a history of fetal death in the index pregnancy, 105 with a poor obstetric history or pregnancy complications and 13 with systemic lupus erythematosus. Antiphospholipid antibodies were found in 41% of women with a history of recurrent miscarriages, 29% with a history of recent intermediate fetal death or stillbirth, 19% with a poor obstetric history and 69% with systemic lupus erythematosus. There is a high incidence of antiphospholipid antibodies in complicated pregnancies. Patients presenting with the above pregnancy disorders should be tested for antiphospholipid antibodies because of the risk conferred on a fetus by their presence and to expand the treatment options.

Inhibin A and activin A in the first trimester of human pregnancy

Recent studies show that high concentrations of inhibin A and activin A are present in the maternal serum throughout human pregnancy. The aim of this study was to determine whether the corpus luteum produces significant quantities of inhibin A and activin A during the first trimester of pregnancy. This prospective study examined two groups of women who had blood samples taken from 5-12 weeks gestation. One group consisted of 14 women with donor egg pregnancies (8 singletons and 6 multiples) who did not have corpora lutea, and the other group consisted 5 women with spontaneous pregnancies who had corpora lutea. Inhibin A and activin A were measured at weekly intervals using specific enzyme immunoassays. All pregnancies progressed to term, with healthy babies being delivered. Maternal serum concentrations of inhibin A significantly increased throughout the study period in the donor egg pregnancies (P < 0.001) and the control pregnancies (P < 0.001). Circulating concentrations of activin A also increased significantly in both the spontaneous and donor egg pregnancies (P < 0.001) during the study period. However, the concentrations of inhibin A and activin A in the first trimester of human pregnancy were not significantly different in the women with or without corpora lutea, suggesting a fetoplacental origin. Multiple donor egg pregnancies were found to have higher concentrations of inhibin A (P < 0.001) and activin A (P < 0.05) compared with singleton donor egg pregnancies, which also supports a placental source.

Transabdominal versus transvaginal ultrasound in the diagnosis of polycystic ovaries in a population of randomly selected women

A study was conducted which compared transvaginal and transabdominal ultrasound in determining the prevalence of polycystic ovaries in a population of women. Women, chosen randomly from electoral rolls, were sent a letter inviting them to take part in a study determining the presence of polycystic ovaries. A transvaginal and transabdominal ultrasound scan was performed on day 5-9 of their menstrual cycles. A total of 187 women (mean age 33 years) took part in the study. The prevalence of polycystic ovaries was 21% (40/187) by transabdominal ultrasound and 27% (36/134) by transvaginal ultrasound. No differences existed between women with polycystic and normal ovaries with respect to uterine size and endometrial thickness. Mean ovarian volume was larger in women with polycystic ovaries irrespective of the use of hormonal contraception or breast feeding. There was no difference in the prevalence of polycystic ovaries diagnosed by transabdominal or transvaginal ultrasound in the group of randomly selected women. However, almost 20% of the women declined a transvaginal ultrasound examination.

12-O-tetradecanoyl-phorbol-13-acetate down-regulates the Huntingtin promoter at Sp1 sites

We have studied the effects of the phorbol ester, 12-O-tetradecanoyl-phorbol-13-acetate (TPA) on Huntington's disease (HD) gene transcription in neuronal and non-neuronal cell lines, to investigate pathways regulating HD gene expression. TPA reduced transcription from the HD gene promoter in SK-N-SH (neuroblastoma) and HeLa cells but not in JEG3 (choriocarcinoma) cells. In SK-N-SH cells, the responsible cis-acting promoter sequences comprise the tandemly duplicated Sp1 sites in the region from -213 to -174, relative to the translation start site. The TPA-down-regulating region in HeLa cells was mapped to the sequence from -141 to -126. In conclusion, this demonstrates that HD gene transcription can be down-regulated in vitro in a cell-specific manner.

Localization of Jacobsen syndrome breakpoints on a 40-Mb physical map of distal chromosome 11q

Jacobsen syndrome is a haploinsufficiency disorder caused, most frequently by terminal deletion of part of the long arm of chromosome 11, with breakpoints in 11q23.3-11q24.2. Inheritance of an expanded p(CCG)n trinucleotide repeat at the folate-sensitive fragile site FRA11B has been implicated in the generation of the chromosome breakpoint in several Jacobsen syndrome patients. The majority of such breakpoints, however, map distal to this fragile site and are not linked with its expression. To characterize these distal breakpoints and ultimately to further investigate the mechanisms of chromosome breakage, a 40-Mb YAC contig covering the distal long arm of chromosome 11 was assembled. The utility of the YAC contig was demonstrated in three ways: (1) by rapidly mapping the breakpoints from two new Jacobsen syndrome patients using FISH; (2) by demonstrating conversion to high resolution PAC contigs after direct screening of PAC library filters with a YAC clone containing a Jacobsen syndrome breakpoint; and (3) by placing 23 Jacobsen syndrome breakpoints on the physical map. This analysis has suggested the existence of at least two new Jacobsen syndrome breakpoint cluster regions in distal chromosome 11.

Chorionic villus sampling in Auckland 1989-90

AIMS

to perform an audit of all 197 chorionic villus sampling procedures performed in Auckland in 1989-90.

METHOD

an attempt to trace the outcome in all 197 cases and this was possible in 188 cases.

RESULTS

89% of chorionic villus samples were performed transvaginally and 11% transabdominally. The total fetal loss rate was 9.6% (18) with six spontaneous miscarriages before 20 weeks gestation (3.2%), one intermediate fetal death and one neonatal death. There were 10 elective terminations of pregnancy following abnormal results so the spontaneous loss rate was 4.3%.

CONCLUSIONS

the loss rate was lower than that reported in the European and Canadian multicentre trials. The sampling success rate, however, was poor with 13.7% failed procedures. This improved in the second year of the service to 10%. There were no failure cultures or examples of mosaicism.

Rosacea: Practical Guidance and Challenges for Clinical Management

Rosacea is a common chronic dermatosis. Clinically, rosacea can present with flushing, erythema, papules, pustules, telangiectasias, phymatous changes, pruritus, burning, and stinging. In 2017, the National Rosacea Society Expert Committee recommended a phenotype-based classification for therapy. In this review, we identify monotherapies and multimodal treatment approaches for the clinical management of rosacea including topical, systemic, laser and light, alternative, and combination therapies.