Joanna Latter

Progesterone activates multiple innate immune pathways in Chlamydia trachomatis-infected endocervical cells.

Susceptibility to Chlamydia trachomatis infection is increased by oral contraceptives and modulated by sex hormones. We therefore sought to determine the effects of female sex hormones on the innate immune response to C. trachomatis infection.

Modulation of the Chlamydia trachomatis in vitro transcriptome response by the sex hormones estradiol and progesterone.

BackgroundChlamydia trachomatis is a major cause of sexually transmitted disease in humans. Previous studies in both humans and animal models of chlamydial genital tract infection have suggested that the hormonal status of the genital tract epithelium at the time of exposure can influence the outcome of the chlamydial infection. We performed a whole genome transcriptional profiling study of C. trachomatis infection in ECC-1 cells under progesterone or estradiol treatment.ResultsBoth hormone treatments caused a significant shift in the sub-set of genes expressed (25% of the transcriptome altered by more than 2-fold). Overall, estradiol treatment resulted in the down-regulation of 151 genes, including those associated with lipid and nucleotide metabolism. Of particular interest was the up-regulation in estradiol-supplemented cultures of six genes (omcB, trpB, cydA, cydB, pyk and yggV), which suggest a stress response similar to that reported previously in other models of chlamydial persistence. We also observed morphological changes consistent with a persistence response. By comparison, progesterone supplementation resulted in a general up-regulation of an energy utilising response.ConclusionOur data shows for the first time, that the treatment of chlamydial host cells with key reproductive hormones such as progesterone and estradiol, results in significantly altered chlamydial gene expression profiles. It is likely that these chlamydial expression patterns are survival responses, evolved by the pathogen to enable it to overcome the hosts innate immune response. The induction of chlamydial persistence is probably a key component of this survival response.

Prevalence of unhealthy alcohol use in hospital outpatients

BACKGROUND Few studies have examined the prevalence of unhealthy alcohol use in the hospital outpatient setting. Our aim was to estimate the prevalence of unhealthy alcohol use among patients attending a broad range of outpatient clinics at a large public hospital in Australia. METHODS Adult hospital outpatients were invited to complete the Alcohol Use Disorders Identification Test Consumption questions (AUDIT-C) using an iPad as part of a randomised trial testing the efficacy of alcohol electronic screening and brief intervention. Unhealthy alcohol use was defined as an AUDIT-C score ≥5 among men and ≥4 among women. RESULTS Sixty percent (3616/6070) of invited hospital outpatients consented, of whom 89% (3206/3616) provided information on their alcohol consumption (either reported they had not consumed any alcohol in the last 12 months or completed the AUDIT-C). The prevalence of unhealthy alcohol use was 34.7% (95% confidence interval [CI]: 33.0-36.3%). The prevalence among men aged 18-24 years, 25-39 years, 40-59 years and 60 years and older, was 74.4% (95% CI: 68.4-80.4%), 54.3% (95% CI: 48.7-59.8%), 44.1% (95% CI: 39.9-48.3%), and 27.0% (95% CI: 23.6-30.4%), respectively (43.1% overall; 95% CI: 40.8-45.5%). The prevalence among women aged 18-24 years, 25-39 years, 40-59 years, and 60 years and older, was 48.6% (95% CI: 39.2-58.1%), 36.9% (95% CI: 31.2-42.6%), 25.2% (95% CI: 21.5-29.0%) and 14.5% (95% CI: 11.7-17.3%), respectively (24.9% overall; 95% CI: 22.7-27.1%). CONCLUSION A large number of hospital outpatients who are not currently seeking treatment for their drinking could benefit from effective intervention in this setting.

Interactions of the gasotransmitters contribute to microvascular tone (Dys)regulation in the preterm neonate

Background & Aims Hydrogen sulphide (H2S), nitric oxide (NO), and carbon monoxide (CO) are involved in transitional microvascular tone dysregulation in the preterm infant; however there is conflicting evidence on the interaction of these gasotransmitters, and their overall contribution to the microcirculation in newborns is not known. The aim of this study was to measure the levels of all 3 gasotransmitters, characterise their interrelationships and elucidate their combined effects on microvascular blood flow. Methods 90 preterm neonates were studied at 24h postnatal age. Microvascular studies were performed by laser Doppler. Arterial COHb levels (a measure of CO) were determined through co-oximetry. NO was measured as nitrate and nitrite in urine. H2S was measured as thiosulphate by liquid chromatography. Relationships between levels of the gasotransmitters and microvascular blood flow were assessed through partial correlation controlling for the influence of gestational age. Structural equation modelling was used to examine the combination of these effects on microvascular blood flow and derive a theoretical model of their interactions. Results No relationship was observed between NO and CO (p = 0.18, r = 0.18). A positive relationship between NO and H2S (p = 0.008, r = 0.28) and an inverse relationship between CO and H2S (p = 0.01, r = -0.33) exists. Structural equation modelling was used to examine the combination of these effects on microvascular blood flow. The model with the best fit is presented. Conclusions The relationships between NO and H2S, and CO and H2S may be of importance in the preterm newborn, particularly as NO levels in males are associated with higher H2S levels and higher microvascular blood flow and CO in females appears to convey protection against vascular dysregulation. Here we present a theoretical model of these interactions and their overall effects on microvascular flow in the preterm newborn, upon which future mechanistic studies may be based.

A role for H2S in the microcirculation of newborns: the major metabolite of H2S (thiosulphate) is increased in preterm infants.

Excessive vasodilatation during the perinatal period is associated with cardiorespiratory instability in preterm neonates. Little evidence of the mechanisms controlling microvascular tone during circulatory transition exists. We hypothesised that hydrogen sulphide (H2S), an important regulator of microvascular reactivity and central cardiac function in adults and animal models, may contribute to the vasodilatation observed in preterm newborns. Term and preterm neonates (24–43 weeks gestational age) were studied. Peripheral microvascular blood flow was assessed by laser Doppler. Thiosulphate, a urinary metabolite of H2S, was determined by high performance liquid chromatography as a measure of 24 hr total body H2S turnover for the first 3 days of postnatal life. H2S turnover was greatest in very preterm infants and decreased with increasing gestational age (p = 0.0001). H2S turnover was stable across the first 72 hrs of life in older neonates. In very preterm neonates, H2S turnover increased significantly from day 1 to 3 (p = 0.0001); and males had higher H2S turnover than females (p = 0.04). A significant relationship between microvascular blood flow and H2S turnover was observed on day 2 of postnatal life (p = 0.0004). H2S may play a role in maintaining microvascular tone in the perinatal period. Neonates at the greatest risk of microvascular dysfunction characterised by inappropriate peripheral vasodilatation - very preterm male neonates - are also the neonates with highest levels of total body H2S turnover suggesting that overproduction of this gasotransmitter may contribute to microvascular dysfunction in preterms. Potentially, H2S is a target to selectively control microvascular tone in the circulation of newborns.

Early microvascular changes in the preterm neonate: a comparative study of the human and guinea pig

Dysfunction of the transition from fetal to neonatal circulatory systems may be a major contributor to poor outcome following preterm birth. Evidence exists in the human for both a period of low flow between 5 and 11 h and a later period of increased flow, suggesting a hypoperfusion–reperfusion cycle over the first 24 h following birth. Little is known about the regulation of peripheral blood flow during this time. The aim of this study was to conduct a comparative study between the human and guinea pig to characterize peripheral microvascular behavior during circulatory transition. Very preterm (≤28 weeks GA), preterm (29–36 weeks GA), and term (≥37 weeks GA) human neonates underwent laser Doppler analysis of skin microvascular blood flow at 6 and 24 h from birth. Guinea pig neonates were delivered prematurely (62 day GA) or at term (68–71 day GA) and laser Doppler analysis of skin microvascular blood flow was assessed every 2 h from birth. In human preterm neonates, there is a period of high microvascular flow at 24 h after birth. No period of low flow was observed at 6 h. In preterm animals, microvascular flow increased after birth, reaching a peak at 10 h postnatal age. Blood flow then steadily decreased, returning to delivery levels by 24 h. Preterm birth was associated with higher baseline microvascular flow throughout the study period in both human and guinea pig neonates. The findings do not support a hypoperfusion–reperfusion cycle in the microcirculation during circulatory transition. The guinea pig model of preterm birth will allow further investigation of the mechanisms underlying microvascular function and dysfunction during the initial extrauterine period.

Videomicroscopy as a tool for investigation of the microcirculation in the newborn

The perinatal period remains a time of significant risk of death or disability. Increasing evidence suggests that this depends on microcirculatory behavior. Sidestream dark‐field orthogonal polarized light videomicroscopy (OPS) has emerged as a useful assessment of adult microcirculation but the values derived are not delineated for the newborn. We aimed to define these parameters in well term newborn infants. Demographic details were collected prospectively on 42 healthy term neonates (n = 20 females, n = 22 males). OPS videomicroscopy (Microscan) was used to view ear conch skin microcirculation at 6, 24, and 72 h of age. Stored video was analyzed by a masked observer using proprietary software. There were no significant differences between the sexes for any structural parameters at any time point. There was a significant increase over time in small vessel perfusion in female infants only (P = 0.009). A number of 6‐ and 72‐h measurements were significantly correlated, but differed from the 24‐h values. These observations confirm the utility of the ear conch for neonatal microvascular videomicroscopy. They provide a baseline for studies into the use of OPS videomicroscopy in infants. The changes observed are comparable with previous studies of term infants using these and other microvascular techniques. It is recommended that studies for examining the mature neonatal microvascular structure be delayed until 72 h of life, but studies of the physiology of cardiovascular transition should include the 24‐h time point after delivery.

Influence of sympathetic activity in the control of peripheral microvascular tone in preterm infants

Background:Microvascular dysregulation following preterm birth is associated with increased illness severity and hypotension, particularly in males. Sympathetic nervous vascular regulation is evident in females. We hypothesized that sympathetic dysfunction in male preterm infants may contribute to a failure of peripheral microvascular vasoconstriction.Methods:Microvascular blood flow of infants 24–43 wk gestational age was assessed at 6, 24, and 72 h of age by laser Doppler. Blood flow Fourier transformed frequency distribution spectra (low frequency/high frequency ratio) were used to assess the influence of sympathetic tone on microvascular regulation. Total sympathetic output was assessed as urinary normetanephrine.Results:Microvascular sympathetic activity at 24 h postnatal age decreased in early preterm males, but not females. Peripheral sympathetic activity increased with advancing postnatal age in females, but decreased in males. In early preterm infants, total normetanephrine outputs increase significantly with postnatal age, in both sexes.Conclusion:Sympathetic activation following preterm birth is sexually dimorphic, with preterm males having reduced sympathetic tone and reduced upregulation of sympathetic tone following birth. There is evidence of a disconnect between central sympathetic activity and local peripheral microcirculatory sympathetic drive. This may relate to autonomic nervous immaturity and highlights the need to understand how preterm birth may affect autonomic function.

Effect of electronic screening and brief intervention on hazardous or harmful drinking among adults in the hospital outpatient setting: A randomized, double-blind, controlled trial

BACKGROUND Most trials of electronic alcohol screening and brief intervention (e-SBI) have been conducted in young people. The aim of this study was to evaluate the effect of e-SBI in adults with hazardous or harmful drinking. METHODS This individually randomized, parallel, two-group, double-blind controlled trial was conducted in the outpatient department of a large public hospital in Australia. Consenting adults who scored 5-9 on the AUDIT-C (837/3225; 26%) were randomized in a 1:1 ratio by computer to screening alone (442/837; 53%) or to 10 min of assessment and personalized feedback on their alcohol consumption (comparisons with medical guidelines and age and sex-specific norms), peak blood alcohol concentration, expenditure on alcohol, and risk of alcohol dependence (395/837; 47%). The two primary outcomes, assessed six months after randomization, were the number of standard drinks (10 g ethanol) consumed by participants in the last seven days and their AUDIT score. RESULTS 693/837 (83%) and 635/837 (76%) participants were followed-up at 6 and 12 months, respectively. There was no statistically significant difference between the groups in the median number of standard drinks consumed in the last seven days (intervention: 12; control: 10.5; rate ratio, 1.12 [95% confidence interval, 0.96-1.31]; P = .17) or in their median AUDIT score (intervention: 7; control: 7; mean difference, 0.28 [-0.42 to 0.98]; P = .44). CONCLUSION These results do not support the implementation of an e-SBI program comprising personalized feedback and normative feedback for adults with hazardous or harmful drinking in the hospital outpatient setting.

Effect of telephone follow-up on retention and balance in an alcohol intervention trial

Objectives Telephone follow-up is not currently recommended as a strategy to improve retention in randomized trials. The aims of this study were to estimate the effect of telephone follow-up on retention, identify participant characteristics predictive of questionnaire completion during or after telephone follow-up, and estimate the effect of including participants who provided follow-up data during or after telephone follow-up on balance between randomly allocated groups in a trial estimating the effect of electronic alcohol screening and brief intervention on alcohol consumption in hospital outpatients with hazardous or harmful drinking. Method Trial participants were followed up 6 months after randomization (June–December 2013) using e-mails containing a hyperlink to a web-based questionnaire when possible and by post otherwise. Telephone follow-up was attempted after two written reminders and participants were invited to complete the questionnaire by telephone when contact was made. Results Retention before telephone follow-up was 62.1% (520/837) and 82.8% (693/837) afterward: an increase of 20.7% (173/837). Therefore, 55% (95% CI 49%–60%) of the 317 participants who had not responded after two written reminders responded during or after the follow-up telephone call. Age < 55 years, a higher AUDIT-C score and provision of a mobile/cell phone number were predictive of questionnaire completion during or after telephone follow-up. Balance between randomly allocated groups was present before and after inclusion of participants who completed the questionnaire during or after telephone follow-up. Conclusion Telephone follow-up improved retention in this randomized trial without affecting balance between the randomly allocated groups.