Predicting adverse outcomes in pregnant patients positive for SARS-CoV-2: a machine learning approach- a retrospective cohort study.

BACKGROUND: Pregnant people are particularly vulnerable to SARS-CoV-2 infection and to ensuing severe illness. Predicting adverse maternal and perinatal outcomes could aid clinicians in deciding on hospital admission and early initiation of treatment in affected individuals, streamlining the triaging processes. METHODS: An international repository of 1501 SARS-CoV-2-positive cases in pregnancy was created, consisting of demographic variables, patient comorbidities, laboratory markers, respiratory parameters, and COVID-19-related symptoms. Data were filtered, preprocessed, and feature selection methods were used to obtain the optimal feature subset for training a variety of machine learning models to predict maternal or fetal/neonatal death or critical illness. RESULTS: The Random Forest model demonstrated the best performance among the trained models, correctly identifying 83.3% of the high-risk patients and 92.5% of the low-risk patients, with an overall accuracy of 89.0%, an AUC of 0.90 (95% Confidence Interval 0.83 to 0.95), and a recall, precision, and F1 score of 0.85, 0.94, and 0.89, respectively. This was achieved using a feature subset of 25 features containing patient characteristics, symptoms, clinical signs, and laboratory markers. These included maternal BMI, gravidity, parity, existence of pre-existing conditions, nicotine exposure, anti-hypertensive medication administration, fetal malformations, antenatal corticosteroid administration, presence of dyspnea, sore throat, fever, fatigue, duration of symptom phase, existence of COVID-19-related pneumonia, need for maternal oxygen administration, disease-related inpatient treatment, and lab markers including sFLT-1/PlGF ratio, platelet count, and LDH. CONCLUSIONS: We present the first COVID-19 prognostication pipeline specifically for pregnant patients while utilizing a large SARS-CoV-2 in pregnancy data repository. Our model accurately identifies those at risk of severe illness or clinical deterioration, presenting a promising tool for advancing personalized medicine in pregnant patients with COVID-19.

Counselling Patients for Trial of Labour after Cesarean (TOLAC) and Invasive Placentation: Are We Missing the Mark? The Importance of Local Data and Informed Choice.

OBJECTIVE: Rates of cesarean delivery are increasing, and these procedures carry potential complications, like the risk of invasive placentation, which increases with each cesarean. A trial of labour after cesarean (TOLAC) is a viable option for patients; however, it has been associated with uterine rupture, a complication with maternal and fetal risks. To better counsel patients considering TOLAC, we aimed to determine local uterine rupture rates and maternal and neonatal outcomes with TOLAC and compare these with outcomes related to invasive placentation. METHODS: A 4-year retrospective chart review was conducted at our tertiary centre of all patients with a history of a previous cesarean delivery. We assessed rates of TOLAC, vaginal delivery after cesarean (VBAC), and uterine rupture, as well as maternal and neonatal outcomes associated with invasive placentation. Cases of uterine rupture from 1988 to the present were also reviewed, and their outcomes were compared with those of invasive placentation. RESULTS: Our uterine rupture rate was 0.44% and VBAC rate was 73.8%. We identified 8 cases of uterine rupture since 1988 and 67 invasive placentas during the 4-year chart review. Invasive placentation was associated with a significantly increased risk of neonatal respiratory morbidity, hysterectomy, maternal complications, and longer length of maternal hospital stay when compared with uterine rupture. CONCLUSION: While uterine rupture remains a potential complication of TOLAC, it is rare with overall excellent maternal and neonatal outcomes. Invasive placentation, the risk of which increases with cesarean delivery, carries potentially higher complication rates than uterine rupture. Local complication data is important for individual sites offering TOLAC. The implications of invasive placentation cannot be overlooked when counselling patients considering TOLAC.

Graduating Obstetrics and Gynaecology Residents' Readiness for Practice: A Cross-Sectional Survey Study.

OBJECTIVE: This study sought to evaluate the self-reported and program director-reported comfort of graduating Canadian obstetrics and gynaecology residents in independently performing various surgical skills. METHODS: A Web-based survey was distributed to four cohorts of graduating obstetrics and gynaecology residents across Canada (2014-2017). Residents were asked to indicate their comfort level with independently performing 34 core surgical procedures by using a five-point Likert-type scale. A similar survey was sent to program directors. Comfort scores for residents and program directors were compared using quantitative and qualitative methods as appropriate (Canadian Task Force Classification II-3). RESULTS: Resident and program director survey response rates were 168 of 320 (52.5%) and 20 of 48 (41.7%), respectively. Residents were "comfortable" or "very comfortable" performing 7 of 13 (54%) gynaecology and 4 of 6 (67%) obstetrics List A procedures independently. Program directors reported that residents were "comfortable" or "very comfortable" performing 10 of 13 (77%) gynaecology and 4 of 6 (67%) obstetrics List A procedures. Compared with program directors, residents reported lower comfort with certain minimally invasive and obstetrics List A procedures (P < 0.05). Differences in comfort when performing several List A procedures were related to training program size and plans to pursue fellowship. Qualitative analysis revealed several major and minor themes supporting the dichotomy between residents' lack of comfort and program directors' expectation of comfort. CONCLUSION: Graduating residents were not comfortable performing many core surgical procedures independently. Additionally, program directors believed that trainees were more comfortable than they reported, and comfort varied according to program size and future fellowship plans. The new competency-based curriculum is an opportunity to address this gap.

No. 366-Gynaecologic Management of Hereditary Breast and Ovarian Cancer.

OBJECTIVE: This Committee Opinion outlines the gynaecologic management recommendations for women diagnosed with hereditary breast and ovarian cancer syndrome (HBOC) with respect to screening, contraception, chemoprophylaxis, fertility considerations, risk-reducing surgery, and post-oophorectomy care. INTENDED USERS: This Committee Opinion is designed for gynaecologic oncologists, general gynaecologists, family physicians, genetic counsellors, registered nurses, nurse practitioners, residents, and health care providers. TARGET POPULATION: Adult women (18 years and older) with a pathogenic germline variant in the BRCA1, BRCA2, and other ovarian cancer-associated genes. EVIDENCE: While reviewing evidence, databases searched include Medline, Cochrane, and PubMed. Medical Subject Heading search terms used include BRCA AND gynaecology management, hormone replacement therapy, risk reduction, chemoprophylaxis, fertility from 01/2010 and 10/2017. Literature search was begun 07/2017 and finalized 10/2017. In total 183 studies were identified, and 101 were used. VALIDATION METHODS: The content and recommendations were drafted and agreed upon by the principal authors. The Board of the Society of Obstetricians and Gynaecologists of Canada approved the final draft for publication. The quality of evidence was rated using the criteria described in the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology framework (Table 1). The interpretation of strong and conditional (weak) recommendations is described in Table 2. The Summary of Findings is available upon request. BENEFITS, HARMS, AND COSTS: We may expect a risk reduction of up to 90% in women predisposed to HBOC who undergo risk-reducing bilateral salpingo-oophorectomy. The harms of iatrogenic premature menopause are offset by the benefits of risk reduction. By minimizing potential tubal/ovarian/peritoneal cancers, we can expect savings to the health care system. GUIDELINE UPDATE: Evidence will be reviewed 5 years after publication to decide whether all or part of the opinion should be updated. However, if important new evidence is published prior to the 5-year cycle, the review process may be accelerated for a more rapid update of some recommendations. SPONSORS: This guideline was developed with resources funded by the Society of Obstetricians and Gynaecologists of Canada.

No 366 - Prise en charge gynécologique du cancer du sein et de l'ovaire héréditaire.

OBJECTIF: La présente opinion de comité énumère les recommandations pour la prise en charge gynécologique des femmes ayant reçu un diagnostic de syndrome du cancer du sein et de l'ovaire héréditaire (CSOH) en ce qui a trait au dépistage, à la contraception, à la chimioprophylaxie, aux facteurs à considérer pour la fertilité, à la chirurgie de réduction du risque et aux soins post-ovariectomie. UTILISATEURS CIBLES: La présente opinion de comité s'adresse aux gynécologues oncologues, aux gynécologues généralistes, aux médecins de famille, aux conseillers en génétique, aux infirmières autorisées, infirmières praticiennes, aux résidents et aux autres fournisseurs de soins. POPULATION CIBLE: Les femmes adultes (18 ans et plus) présentant une mutation des gènes BRCA1 ou BRCA2 ou d'autres gènes associés au cancer de l'ovaire. DONNéES: Pour la revue de la littérature, les bases de données Medline, Cochrane et PubMed ont entre autres été interrogées. Les termes de recherche des Medical Subject Headings utilisés ont été BRCA ET gynaecology management [prise en charge gynécologique], hormone replacement therapy [hormonothérapie substitutive], risk reduction [réduction des risques], chemoprophylaxis [chimioprophylaxie] et fertility [fertilité], et les recherches ont ciblé les articles publiés entre janvier 2010 et octobre 2017. La recherche de publications s'est déroulée de juillet à octobre 2017. Au total, 183 études ont été sélectionnées, et 101 ont été utilisées. VALEURS: Le contenu et les recommandations ont été rédigés et acceptés par les auteurs principaux. Le Conseil d'administration de la Société des obstétriciens et gynécologues du Canada a approuvé la version finale avant publication. La qualité des données probantes a été évaluée au moyen des critères de l'approche GRADE (Grading of Recommendations Assessment, Development and Evaluation) [tableau 1]. L'interprétation des recommandations fortes et conditionnelles (faibles) est décrite dans le tableau 2. Le résumé des conclusions peut être fourni sur demande. AVANTAGES DéSAVANTAGES, ET COûTS: Nous pouvons nous attendre à une diminution des risques allant jusqu'à 90 % chez les femmes prédisposées au CSOH qui subissent une salpingo-ovariectomie bilatérale de réduction du risque. Les méfaits associés à la ménopause précoce iatrogène sont compensés par les avantages découlant de la réduction du risque. En réduisant l'occurrence de cancers des trompes, de l'ovaire et du péritoine, nous pouvons nous attendre à des économies dans le système de santé. MIS à JOUR: Une revue des données probantes sera menée cinq ans après la publication de la présente opinion afin de déterminer si une mise à jour complète ou partielle s'impose. Cependant, si de nouvelles données probantes importantes sont publiées avant la fin du cycle de cinq ans, le processus pourrait être accéléré afin que certaines recommandations soient mises à jour rapidement. COMMANDITAIRE: Cette directive clinique a été élaborée à l'aide de ressources financées par la Société des obstétriciens et gynécologues du Canada.

Evaluation of Obstetrics & Gynecology Ultrasound Curriculum and Self-Reported Competency of Final-Year Canadian Residents.

OBJECTIVE: Ultrasonography in obstetrics and gynaecology (OB/GYN) is a vital component of patient assessment, diagnosis, and management. Standards for Canadian obstetrician-gynecologists' ultrasound skills are limited and vague. The primary objective was to audit the current curriculum administered to Canadian OB/GYN residents. The secondary objective was to understand self-perceived competency of final-year residents in performing OB/GYN ultrasound. We also sought to identify perceived barriers to incorporation of ultrasound into practice. METHODS: A cross-sectional questionnaire, distributed to two cohorts of final-year Canadian OB/GYN residents, asked about ultrasound training they received and their perceived competency with respect to specific ultrasound skills. Respondents also answered questions on possible perceived obstacles to independently using ultrasound after graduation. RESULTS: All Canadian residency programs were represented among the 81 respondents out of the possible 167 participants (49%). Ultrasound training varied in its delivery and quantity. The majority of training time was dedicated to obstetrics, with minimal focus on gynaecology. Self-reported competency for obstetric ultrasound was high, whereas that for gynaecologic ultrasound was variable. The main barrier to incorporating ultrasound into future practice was lack of adequate training. CONCLUSIONS: Canadian OB/GYN programs lack standardisation of ultrasound training. The imbalance in training between OB/GYN ultrasound may influence the low levels of self-reported competency in gynaecologic skills in residents. Standardization of ultrasound education and increasing gynaecologic ultrasound training in residency are the necessary first steps in preparing OB/GYN graduates to use ultrasound.

Arteriovenous Malformation Following Conservative Management of Cervical Pregnancy.

BACKGROUND: Medical management using potassium chloride feticide and methotrexate is often the first-line approach to cervical pregnancies. CASE: A 25-year-old woman presenting with a cervical ectopic pregnancy was unsuccessfully managed with conservative therapy, resulting in an arteriovenous malformation requiring a laparoscopic hysterectomy. CONCLUSION: Conservative management of ectopic pregnancies is the treatment of choice for young women looking to preserve fertility. However, medical management is not without risk, and this case illustrates one such complication.

Implementation of a Same-Day Discharge Protocol Following Total Laparoscopic Hysterectomy.

OBJECTIVE: Previous studies have demonstrated that outpatient total laparoscopic hysterectomy (TLH) is both safe and feasible. Our objective was to decrease length of stay for patients undergoing TLH by implementing a same-day discharge protocol at two Canadian teaching hospitals. METHODS: We conducted a prospective cohort study assessing length of stay (primary outcome), perioperative complications, and readmission rates over a 12-month period following implementation of a same-day discharge protocol for TLH. These data were compared with pre-intervention baseline data collected retrospectively over a 12-month period immediately before protocol introduction. Our protocol consisted of patient education, instructions for perioperative care, and close follow-up. RESULTS: In the year prior to our protocol, 256 TLHs were performed. Forty-seven patients (18.3%) were discharged the same day, 191 patients (74.5%) were discharged on the first postoperative day, and 18 patients (7%) were admitted for 2 or more days. In the year following implementation, 215 patients underwent TLH of which 129 were enrolled in our study. The overall outpatient hysterectomy rate during that time period was 62% (134/215 patients). Among study participants, 102 patients (79.1%) were discharged the same day, 22 patients (17.0%) were discharged on the first postoperative day, and 5 patients (3.9%) were admitted for 2 or more days. There were no significant differences in perioperative complications or readmission rates and patient satisfaction scores were high. CONCLUSION: Implementation of a same-day discharge protocol successfully increased the rate of outpatient TLH without impacting patient safety. This protocol was acceptable to both surgeons and patients and can be easily adapted for use at other centres.

Surgical Management Algorithm for Caesarean Scar Pregnancy.

OBJECTIVES: To report our experience with the management of Caesarean scar pregnancy (CSP) in the first trimester and to develop a unique treatment algorithm allowing physicians to customize their management based on clinical patient characteristics. METHODS: A retrospective review of 12 patients diagnosed with CSP between December 2012 and June 2016 was conducted in a tertiary care hospital in Toronto. All patients were diagnosed with CSP by transvaginal ultrasound using radiologic criteria. Patients were initially treated with an ultrasound-guided embryocidal injection when fetal heart activity was present. Next, patients underwent medical management with systemic multidose methotrexate (MTX) or surgical management using a laparoscopic or transcervical approach depending on CSP characteristics. RESULTS: The mean age at diagnosis was 35.6 years. The median number of previous CSs was one. The mean serum human chorionic gonadotropin level was 59 938 IU/L. The mean GA at presentation was 8+1 weeks. Two-thirds of patients received medical management with systemic multidose methotrexate. Of these, 50% required additional surgical treatment for the resolution of their CSP. One-third of patients underwent primary surgical treatment, resulting in complete resolution of CSP with no complications. Given the improved outcomes of surgical management in our series, we suggest a treatment algorithm that tailors the surgical approach, either laparoscopic or transcervical, to the characteristics of the CSP. CONCLUSION: This constitutes the largest case series of CSP in Canada. Based on our results, CSP can be safely and effectively managed using the suggested surgical algorithm, which accounts for individual patient characteristics.

Selective progesterone receptor modulators (SPRMs) for uterine fibroids.

BACKGROUND: Uterine fibroids are smooth muscle tumours arising from the uterus. These tumours, although benign, are commonly associated with abnormal uterine bleeding, bulk symptoms and reproductive dysfunction. The importance of progesterone in fibroid pathogenesis supports selective progesterone receptor modulators (SPRMs) as effective treatment. Both biochemical and clinical evidence suggests that SPRMs may reduce fibroid growth and ameliorate symptoms. SPRMs can cause unique histological changes to the endometrium that are not related to cancer, are not precancerous and have been found to be benign and reversible. This review summarises randomised trials conducted to evaluate the effectiveness of SPRMs as a class of medication for treatment of individuals with fibroids. OBJECTIVES: To evaluate the effectiveness and safety of SPRMs for treatment of premenopausal women with uterine fibroids. SEARCH METHODS: We searched the Specialised Register of the Cochrane Gynaecology and Fertility Group, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, PsycINFO, the Cumulative Index to Nursing and Allied Health Literature (CINAHL) and clinical trials registries from database inception to May 2016. We handsearched the reference lists of relevant articles and contacted experts in the field to request additional data. SELECTION CRITERIA: Included studies were randomised controlled trials (RCTs) of premenopausal women with fibroids who were treated for at least three months with a SPRM. DATA COLLECTION AND ANALYSIS: Two review authors independently reviewed all eligible studies identified by the search. We extracted data and assessed risk of bias independently using standard forms. We analysed data using mean differences (MDs) or standardised mean differences (SMDs) for continuous data and odds ratios (ORs) for dichotomous data. We performed meta-analyses using the random-effects model. Our primary outcome was change in fibroid-related symptoms. MAIN RESULTS: We included in the review 14 RCTs with a total of 1215 study participants. We could not extract complete data from three studies. We included in the meta-analysis 11 studies involving 1021 study participants: 685 received SPRMs and 336 were given a control intervention (placebo or leuprolide). Investigators evaluated three SPRMs: mifepristone (five studies), ulipristal acetate (four studies) and asoprisnil (two studies). The primary outcome was change in fibroid-related symptoms (symptom severity, health-related quality of life, abnormal uterine bleeding, pelvic pain). Adverse event reporting in the included studies was limited to SPRM-associated endometrial changes. More than half (8/14) of these studies were at low risk of bias in all domains. The most common limitation of the other studies was poor reporting of methods. The main limitation for the overall quality of evidence was potential publication bias. SPRM versus placebo SPRM treatment resulted in improvements in fibroid symptom severity (MD -20.04 points, 95% confidence interval (CI) -26.63 to -13.46; four RCTs, 171 women, I2 = 0%; moderate-quality evidence) and health-related quality of life (MD 22.52 points, 95% CI 12.87 to 32.17; four RCTs, 200 women, I2 = 63%; moderate-quality evidence) on the Uterine Fibroid Symptom Quality of Life Scale (UFS-QoL, scale 0 to 100). Women treated with an SPRM showed reduced menstrual blood loss on patient-reported bleeding scales, although this effect was small (SMD -1.11, 95% CI -1.38 to -0.83; three RCTs, 310 women, I2 = 0%; moderate-quality evidence), along with higher rates of amenorrhoea (29 per 1000 in the placebo group vs 237 to 961 per 1000 in the SPRM group; OR 82.50, 95% CI 37.01 to 183.90; seven RCTs, 590 women, I2 = 0%; moderate-quality evidence), compared with those given placebo. We could draw no conclusions regarding changes in pelvic pain owing to variability in the estimates. With respect to adverse effects, SPRM-associated endometrial changes were more common after SPRM therapy than after placebo (OR 15.12, 95% CI 6.45 to 35.47; five RCTs, 405 women, I2 = 0%; low-quality evidence). SPRM versus leuprolide acetate In comparing SPRM versus other treatments, two RCTs evaluated SPRM versus leuprolide acetate. One RCT reported primary outcomes. No evidence suggested a difference between SPRM and leuprolide groups for improvement in quality of life, as measured by UFS-QoL fibroid symptom severity scores (MD -3.70 points, 95% CI -9.85 to 2.45; one RCT, 281 women; moderate-quality evidence) and health-related quality of life scores (MD 1.06 points, 95% CI -5.73 to 7.85; one RCT, 281 women; moderate-quality evidence). It was unclear whether results showed a difference between SPRM and leuprolide groups for reduction in menstrual blood loss based on the pictorial blood loss assessment chart (PBAC), as confidence intervals were wide (MD 6 points, 95% CI -40.95 to 50.95; one RCT, 281 women; low-quality evidence), or for rates of amenorrhoea (804 per 1000 in the placebo group vs 732 to 933 per 1000 in the SPRM group; OR 1.14, 95% CI 0.60 to 2.16; one RCT, 280 women; moderate-quality evidence). No evidence revealed differences between groups in pelvic pain scores based on the McGill Pain Questionnaire (scale 0 to 45) (MD -0.01 points, 95% CI -2.14 to 2.12; 281 women; moderate-quality evidence). With respect to adverse effects, SPRM-associated endometrial changes were more common after SPRM therapy than after leuprolide treatment (OR 10.45, 95% CI 5.38 to 20.33; 301 women; moderate-quality evidence). AUTHORS' CONCLUSIONS: Short-term use of SPRMs resulted in improved quality of life, reduced menstrual bleeding and higher rates of amenorrhoea than were seen with placebo. Thus, SPRMs may provide effective treatment for women with symptomatic fibroids. Evidence derived from one RCT showed no difference between leuprolide acetate and SPRM with respect to improved quality of life and bleeding symptoms. Evidence was insufficient to show whether effectiveness was different between SPRMs and leuprolide. Investigators more frequently observed SPRM-associated endometrial changes in women treated with SPRMs than in those treated with placebo or leuprolide acetate. As noted above, SPRM-associated endometrial changes are benign, are not related to cancer and are not precancerous. Reporting bias may impact the conclusion of this meta-analysis. Well-designed RCTs comparing SPRMs versus other treatments are needed.

Evaluating the effect of distractions in the operating room on clinical decision-making and patient safety.

BACKGROUND: Answering telephone calls and pagers is common distraction in the operating room. We sought to evaluate the impact of distractions on patient care by (1) assessing the accuracy and safety of responses to clinical questions posed to a surgeon while operating and (2) determining whether pager distractions affect simulation-based surgical performance. METHODS: We conducted a randomized crossover study of obstetrics and gynecology residents. After studying a patient sign-out list, subjects performed a virtual salpingectomy. They were randomized to a distraction phase followed by quiet phase or vice versa. In the distraction phase, a pager beeped and subjects were asked questions based on the sign-out list. Accuracy of responses and the number of unsafe responses were recorded. In the quiet phase, trainees performed the task uninterrupted. Measures of surgical performance were successful task completion, time to task completion and operative blood loss. RESULTS: The mean score for correct responses to clinical questions during the distracted phase was 80 % (SD ±14 %). Nineteen residents (63 %) made at least 1 unsafe clinical decision while operating on the simulator (range 0-3). Subjects were more likely to successfully complete the surgical task in the allotted time under the quiet compared to distraction condition (OR 11.3, p = 0.03). There was no difference between the conditions in paired analysis for mean time (seconds) to task completion [426 (SD 133) vs. 440 (SD 186), p = 0.61] and mean operative blood loss (mL) [73.14 (SD 106) vs. 112.70 (SD 358), p = 0.47]. CONCLUSIONS: Distractions in the operating room may have a profound impact on patient safety on the wards. While multitasking in a simulated setting, the majority of residents made at least one unsafe clinical decision. Pager distractions also hindered surgical residents' ability to complete a simulated laparoscopic task in the allotted time without affecting other variables of surgical performance.

Pregnancy outcomes in women with elevated levels of fetal hemoglobin.

OBJECTIVE: Elevated maternal levels of fetal hemoglobin (HbF) present a unique situation where both mother and fetus produce hemoglobin with equivalent oxygen affinities. We aimed to determine pregnancy outcomes in women with persistently elevated HbF. METHODS: In this retrospective cohort study, women with HbF levels exceeding 10% were identified by searching a provincial database. Maternal, obstetric, and neonatal outcomes were extracted from chart reviews performed at two hospitals. RESULTS: Twenty-two women with a total of 43 pregnancies and 33 live births were identified. Maternal levels of HbF ranged between 11 and 100%. Women with HbF ≥ 70% were significantly more likely to deliver growth-restricted or small for gestational age (SGA) fetuses compared to the group of women with HbF < 70% (100% versus 8%; p < 0.01). Three women (4/32 pregnancies) received blood transfusions, which was unrelated to HbF levels. CONCLUSIONS: Pregnancies complicated by maternal HbF levels ≥ 70% are at increased risk of intra-uterine growth restriction or SGA fetuses. Increased antenatal surveillance is suggested.

Angiogenic response of placental villi to heparin.

OBJECTIVE: To estimate the angiogenic effect of heparin on human umbilical vein endothelial cells cultured in conditioned media from normal and severely pre-eclamptic human placental villi. METHODS: Normal first- and second-trimester floating placental villi were explanted in control conditions and increasing concentrations of heparin (unfractionated and low molecular weight heparin) across the clinical prophylactic and therapeutic range (0.025-25 units/mL). At 96 hours, the placenta-conditioned media was tested for angiogenic activity in a human umbilical vein endothelial cell in vitro angiogenesis assay. Total capillary-like tube length and number of branch points were determined from photographs that did not contain information about experimental conditions. The response of placenta-conditioned media from preterm severely preeclamptic pregnant women exposed to low molecular weight heparin also was assessed and compared with both preterm and term control groups. RESULTS: Unfractionated heparin significantly promoted angiogenesis (0.25 units/mL compared with control: relative branch points 185±32% [mean±standard error of the mean], P<.05), whereas low molecular weight heparin had no significant effect. Addition of unfractionated or low molecular weight heparin to first- and second-trimester placenta-conditioned media significantly promoted angiogenesis with the response to low molecular weight heparin more than double that of unfractionated heparin (low molecular weight compared with unfractionated heparin at 2.5 units/mL: relative branch points 930±158% compared with 398±90%, P<.05). Placenta-conditioned media from pregnancies with severe preeclampsia arrested angiogenesis in comparison with both preterm and term pregnancies and was not significantly restored by the addition of low molecular weight heparin. CONCLUSION: Unfractionated and low molecular weight heparin promote in vitro angiogenesis in healthy first- and second-trimester placenta-conditioned media. The nonanticoagulant actions of heparin may be relevant to the prevention of severe preeclampsia.

Propylthiouracil-induced agranulocytosis in the third trimester of pregnancy.

BACKGROUND: Thionamide-induced agranulocytosis in pregnancy is a rare event that poses unique therapeutic challenges. CASE: A 37-year-old woman developed agranulocytosis while taking propylthiouracil in the third trimester. After she took broad-spectrum antibiotics and discontinued propylthiouracil, her neutrophil counts recovered. She was initially managed expectantly but later underwent an uncomplicated total thyroidectomy at 35 weeks of gestation because of patient choice coupled with worsening thyrotoxicosis. CONCLUSION: In circumstances in which thionamides are contraindicated, management options of hyperthyroidism in pregnancy are limited. The proximity to term in the third trimester makes expectant management an attractive approach when maternal thyroid indices are stable, allowing for a choice of postpartum therapies without the worry of fetal implications. However, this strategy carries risks, and thyroidectomy in the third trimester can be a safe alternative.

Antibiotic inducibility of the MexXY multidrug efflux system of Pseudomonas aeruginosa: involvement of the antibiotic-inducible PA5471 gene product.

The MexXY components of the MexXY-OprM multidrug efflux system of Pseudomonas aeruginosa are encoded by a MexZ repressor-regulated operon that is inducible by antibiotics that target the ribosome. Mutant strains disrupted in a gene, PA5471, were shown to be compromised for drug-inducible mexXY expression and, therefore, MexXY-OprM-mediated antimicrobial resistance. The PA5471 gene was inducible by the same ribosome-targeting agents that induce mexXY expression. Moreover, vector-driven expression of cloned PA5471 was sufficient to promote mexXY expression and MexXY-mediated resistance in the absence of antibiotic exposure, consistent with PA5471 directly or indirectly activating mexXY expression following its own upregulation in response to antibiotics. The requirement for PA5471 for mexXY expression and antimicrobial resistance was, however, obviated in mutants lacking the MexZ repressor of mexXY expression, suggesting that PA5471 directly or indirectly modulates MexZ activity in effecting mexXY expression. While the recruitment of PA5471 and MexXY in response to ribosome disruption by antimicrobials is consistent with their genes playing a role in protecting cells from the adverse consequences of disrupting the translation process, reminiscent of trans-translation, these genes appear to operate independently in their contribution to resistance: mutants defective in trans-translation showed a much more modest (twofold) decrease in resistance to ribosome-targeting agents than those lacking PA5471 or MexXY, and this decrease was observed whether functional PA5471/MexXY was present or not.

Induction of the MexXY efflux pump in Pseudomonas aeruginosa is dependent on drug-ribosome interaction.

MexXY is an inducible efflux system that contributes to the natural resistance of Pseudomonas aeruginosa to antibiotics. Experiments involving real-time PCR after reverse transcription in reference strain PAO1 showed concentration-dependent induction of gene mexY by various ribosome inhibitors (e.g., chloramphenicol, tetracycline, macrolides, and aminoglycosides) but not by antibiotics acting on other cellular targets (e.g., beta-lactams, fluoroquinolones). Confirming a functional link between the efflux system and the translational machinery, ribosome protection by plasmid-encoded proteins TetO and ErmBP increased the resistance of a DeltamexAB-oprM mutant of PAO1 to tetracycline and erythromycin, respectively, as well as the concentrations of both drugs required to induce mexY. Furthermore, spontaneous mutations resulting in specific resistance to dihydrostreptomycin or spectinomycin also raised the minimal drug concentration for mexXY induction in strain PAO1. While strongly upregulated in a PAO1 mutant defective in gene mexZ (which codes for a putative repressor of operon mexXY), gene mexY remained inducible by agents such as tetracycline, chloramphenicol, and spectinomycin, suggesting additional regulatory loci for mexXY. Altogether, these data demonstrate physiological interplays between MexXY and the ribosome and are suggestive of an alternative function for MexXY beyond antibiotic efflux.

Mutations in PA3574 (nalD) lead to increased MexAB-OprM expression and multidrug resistance in laboratory and clinical isolates of Pseudomonas aeruginosa.

Mutations in genes mexR and nalC have previously been shown to drive overexpression of the MexAB-OprM multidrug efflux system in Pseudomonas aeruginosa. A transposon insertion multidrug-resistant mutant of P. aeruginosa overproducing MexAB-OprM was disrupted in yet a third gene, PA3574, encoding a probable repressor of the TetR/AcrR family that we have dubbed NalD. Clinical strains overexpressing MexAB-OprM but lacking mutations in mexR or nalC were also shown to carry mutations in nalD. Moreover, the cloned nalD gene reduced the multidrug resistance and MexAB-OprM expression of the transposon mutant and clinical isolates, highlighting the significance of the nalD mutations vis-a-vis MexAB-OprM overexpression in these isolates.

Mutations in PA2491 (mexS) promote MexT-dependent mexEF-oprN expression and multidrug resistance in a clinical strain of Pseudomonas aeruginosa.

Disruption of the PA2491 gene in a mini-Tn5-tet insertion mutant of a clinical isolate of Pseudomonas aeruginosa increased expression of the mexEF-oprN multidrug efflux genes and decreased production of outer membrane protein OprD, concomitant with enhanced resistance to chloramphenicol, quinolones, and imipenem, which was reminiscent of previously described nfxC mutants. PA2491 encodes a probable oxidoreductase previously shown to be positively regulated by the MexT positive regulator of mexEF-oprN expression (T. Kohler, S. F. Epp, L. K. Curty, and J. C. Pechere, J. Bacteriol. 181:6300-6305, 1999). Spontaneous multidrug-resistant mutants of the P. aeruginosa clinical isolate hyperexpressing mexEF-oprN and showing reduced production of OprD were readily selected in vitro, and all of them were shown to carry mutations in PA2491, highlighting the probable significance of such mutations as determinants of MexEF-OprN-mediated multidrug resistance in vivo.