Comparative Molecular Dynamics Simulation Studies of Realistic Eukaryotic, Prokaryotic, and Archaeal Membranes.

We present a comparative all-atom molecular dynamics simulation study of 18 biomembrane systems with lipid compositions corresponding to eukaryotic, bacterial, and archaebacterial membranes together with three single-component lipid bilayers. A total of 105 lipid types used in this study include diverse sterols and glycerol-based lipids with acyl chains of various lengths, unsaturation degrees, and branched or cyclic moieties. Our comparative analysis provides deeper insight into the influences of sterols and lipid unsaturation on the structural and mechanical properties of these biomembranes, including water permeation into the membrane hydrocarbon core. For sterol-containing membranes, sterol fraction is correlated with the membrane thickness, the area compressibility modulus, and lipid order but anticorrelated with the area per lipid and sterol tilt angles. Similarly, for all 18 biomembranes, lipid order is correlated with the membrane thickness and area compressibility modulus. Sterols and lipid unsaturation produce opposite effects on membrane thickness, but only sterols influence water permeation into the membrane. All membrane systems are accessible for public use in CHARMM-GUI Archive. They can be used as templates to expedite future modeling of realistic cell membranes with transmembrane and peripheral membrane proteins to study their structure, dynamics, molecular interactions, and function in a nativelike membrane environment.

Glycemic Control and Aspirin Resistance in Patients Taking Low-Dose Aspirin for Pre-eclampsia Prevention.

OBJECTIVES: To assess the association between aspirin and glycemic control in diabetic, pregnant patients, and the risk for aspirin resistance in those with poor glycemic control across gestation taking low-dose aspirin (LDA) for pre-eclampsia (PEC) prevention. STUDY DESIGN: We performed a secondary analysis of samples collected during the Maternal-Fetal Medicine Units trial of LDA for PEC prevention. A subset of insulin-controlled diabetic patient samples on placebo or 60 mg aspirin daily were evaluated. Glycosylated hemoglobin was measured at randomization, mid-second trimester, and third trimester time points. Thromboxane B2 (TXB2) measurements were previously assessed as part of the original study. Primary outcome was the effect of LDA on glycosylated hemoglobin levels compared with placebo across gestation. RESULTS: Levels of glycosylated hemoglobin increased across gestation in the placebo group (2,067.7 [interquartile range, IQR: 1,624.6-2,713.5 µg/mL] vs. 2,461.9 [1,767.0-3,209.9 µg/mL] vs. 3,244.3 [2,691.5-4,187.0 µg/mL]; p < 0.01) compared with no difference in levels of glycosylated hemoglobin across gestation in the LDA group (2,186.4 [IQR: 1,462.3-3,097.7 µg/mL] vs. 2,337.1 [1,327.7-5,932.6 µg/mL] vs. 2,532.9 [1,804.9-5,511.8 µg/mL]; p = 0.78). Higher levels of glycosylated hemoglobin were associated with increased TXB2 levels prior to randomization (r = 0.67, p < 0.05). Incomplete TXB2 was higher in pregnancies with increasing levels of glycosylated hemoglobin compared with those with decreasing levels of glycosylated hemoglobin across gestation (69.2 vs. 18.1%, p = 0.02). CONCLUSION: LDA exposure may be beneficial to glycemic control in this patient population. Additionally, poor glycemic control is associated with a higher level of TXB2 in diabetic pregnant patients on LDA. Higher doses of aspirin may be required in these patients to prevent development of PEC. KEY POINTS: · Low-dose aspirin may improve glycemic control.. · Poor glycemic control increases risk for aspirin resistance.. · Higher doses of aspirin may be required for pre-eclampsia prevention..

Outcomes of Isolated Fetal Ventriculomegaly That Resolve In Utero.

OBJECTIVE: Isolated fetal ventriculomegaly is often an incidental finding on antenatal ultrasound. It is benign in up to 90% of cases, although it can be associated with genetic, structural, and neurocognitive disorders. The literature suggests that over 40% of isolated mild ventriculomegaly will resolve in utero, but it is unclear if resolution decreases the associated risks.The aim of this study is to compare the fetal and neonatal genetic outcomes of ventriculomegaly that persists or resolves on subsequent ultrasound. STUDY DESIGN: This is a retrospective cohort study of women diagnosed with isolated ventriculomegaly via fetal ultrasound at a tertiary referral center between 2011 and 2019. Patients were excluded if other structural anomalies were identified on ultrasound. RESULTS: A total of 49 patients were included in the study, 19 in the resolved ventriculomegaly group and 30 in the persistent ventriculomegaly group. Women in the resolved ventriculomegaly group were more likely to be diagnosed earlier (24 vs. 28 weeks, p = 0.007). Additionally, they were more likely to have mild ventriculomegaly (63 vs. 84%, p = 0.15), and less likely to have structural neurological abnormalities diagnosed on postnatal imaging (5 vs. 17%, p = 0.384), although these were not statistically significant. Aneuploidy risk for resolved compared with persistent ventriculomegaly was similar (5 vs. 7%, p = 0.999). CONCLUSION: This study suggests that resolution of isolated ventriculomegaly in utero may not eliminate the risk of genetic or chromosomal abnormalities in this population and may warrant inclusion as part of the counselling of these at-risk patients. Larger prospective studies are needed to confirm these findings. KEY POINTS: · Ventriculomegaly is known to be associated with genetic and chromosomal abnormalities.. · Resolution of the ventriculomegaly in utero may not eliminate those risks.. · Patients with resolved ventriculomegaly should be offered aneuploidy screening or testing..

Fetal renal artery impedance in pregnancies affected by preeclampsia.

Background Preeclampsia (PE) is a pregnancy-specific vascular endothelial disorder characterized by multi-organ system involvement. This includes the maternal kidneys, with changes such as continuous vasospasm of renal arteries and reduced renal blood flow. However, it is unclear whether similar renal vascular changes are seen in the fetus. This study sought to compare renal artery impedance in fetuses of women with and without PE. Methods This was a prospective Doppler assessment study of the fetal renal artery impedance in 48 singleton fetuses. The group with PE consisted of 24 appropriately grown fetuses in pregnancy complicated by both mild and severe PE and a control group of 24 uncomplicated pregnancies. Doppler studies included renal artery systolic/diastolic (S/D) ratio, pulsatility index (PI), resistance index (RI), and identification of end-diastolic blood flow. Results Fetuses of mothers with PE were more likely to have a lower renal artery Doppler S/D ratio (7.85 [6.4-10.2] vs. 10.8 [7.75-22.5], P = 0.03) and lower RI (0.875 [0.842-0.898] vs. 0.905 [0.872-0.957], P = 0.03). However, there was no statistically significant difference in PI. There was also no difference in the incidence of absent end-diastolic flow. Conclusion This study suggests that PE results in changes in blood flow to the renal arteries of the fetus. This may be associated with long-term adverse health effects later in adulthood.

Intrauterine Pressure Catheter Use Is Associated with an Increased Risk of Postcesarean Surgical Site Infections.

OBJECTIVE: This study aimed to determine if intrapartum placement of an intrauterine pressure catheter (IUPC) is associated with an increased rate of surgical site infections in women undergoing a cesarean delivery. STUDY DESIGN: This was a secondary analysis of the prospective observational Maternal-Fetal Medicine Units Network Vaginal Birth after Cesarean Registry. We compared patients with and without IUPC use. A multivariable logistic regression was performed to evaluate for an association between IUPC use and postcesarean surgical site infections. RESULTS: The study included 16,887 women: 7,441 with IUPC use and 9,446 without IUPC use. After adjustment for potential cofounders, IUPC use was associated with an increased risk of postcesarean infections compared with those without IUPC use (adjusted odds ratio: 1.28; 95% confidence interval: 1.10-1.50; p = 0.002). CONCLUSION: IUPC use is associated with an increased risk of postcesarean surgical site infections. This supports the judicious use of IUPC for limited clinical indications and provides a potential area of focus for reduction in postcesarean infections.

Meconium-stained amniotic fluid and the risk of postcesarean surgical site infection.

OBJECTIVE: To investigate the association between meconium-stained amniotic fluid (MSAF) and postcesarean surgical site infections. METHODS: This was a secondary analysis of the Maternal-Fetal Medicine Units Network (MFMU) Cesarean Registry. Women with a singleton pregnancy attempting labor or induction of labor, who ultimately had a cesarean delivery, were included in the study. Pregnancies complicated by MSAF (n = 4262) and those who did not have MSAF (n = 13,850) were compared. The primary outcome was the incidence of SSI. RESULTS: A total of 18,112 patients were included in the study. 4262 (38%) had meconium-stained amniotic fluid. After accounting for potential confounders in a multivariable logistic regression, meconium-stained amniotic fluid was associated with an increased risk of postoperative surgical site infection (odds ratio 1.16, 95% CI 1.03-1.30). CONCLUSIONS: Meconium-stained amniotic fluid may be associated with an increased risk of postoperative surgical site infection.

Addition of vaginal isosorbide mononitrate for labor induction in pregnancies complicated by hypertensive diseases of pregnancy: a randomized controlled trial.

BACKGROUND: Pregnancies complicated by hypertensive disease of pregnancy often require labor induction. Rates of cesarean delivery range from 15% to 60% in this population. Nitric oxide deficiency has been shown to underlay the pathophysiology of preeclampsia, and nitric oxide promotes cervical ripening. OBJECTIVE: We hypothesized that addition of vaginal isosorbide mononitrate for labor induction could decrease the rate of cesarean delivery in pregnancies with hypertensive disease of pregnancy. STUDY DESIGN: This study was a double-blind, placebo-controlled, randomized trial of patients with singleton pregnancy at ≥24 weeks' gestation undergoing labor induction for hypertensive diseases of pregnancy between November 2017 and February 2020. Participants were eligible if their Bishop score was <6 and if their cervical dilation was ≤2 cm. In addition, participants received up to 3 doses of 40 mg isosorbide mononitrate in addition to misoprostol for labor induction. Labor management was per healthcare provider preference. The primary outcome was rate of cesarean delivery. Secondary outcomes included the length of labor and frequency of intrapartum adverse events, including the use of intrapartum antihypertensive agents. RESULTS: 89 women were randomized to the isosorbide mononitrate group, and 87 women were randomized to the placebo group. Cesarean delivery rates were similar in both groups (32.6% vs 25.3%; relative risk, 1.29; 95% confidence interval, 0.81-2.06; P=.39). Maternal headache was increased in patients exposed to isosorbide mononitrate (42.7% vs 31%; relative risk, 1.52; 95% confidence interval, 1.04-2.23; P=.04). Clinical chorioamnionitis was increased in the placebo group (0% vs 8%; P=.02). Secondary outcomes were similar between groups. CONCLUSION: The addition of vaginal isosorbide mononitrate for labor induction in pregnancies complicated by hypertensive disease of pregnancy did not result in fewer cesarean deliveries.

Decline in Sars-CoV-2 antibodies over 6-month follow-up in obstetrical healthcare workers.

PROBLEM: Limited data exists on the temporal trend of the Sars-CoV-2 immunologic response and duration of protection following natural infection. We sought to investigate the presence and duration of Sars-CoV-2 serum antibodies in obstetrical healthcare workers (HCW) on serial assessments over a 6-month period, and to assess rates of vaccine acceptance and reported vaccine side effects among this cohort. METHOD OF STUDY: A prospective cohort study of a convenience sample of obstetrical HCWs at a tertiary hospital. Serum Sars-CoV-2 antibodies for Immunoglobulin G (IgG) and Immunoglobulin M (IgM) were measured longitudinally at four intervals: baseline, 4 weeks, 12 weeks, and 6 months. Participants completed voluntary surveys on COVID19 testing, high-risk exposures, vaccine acceptance, and vaccine side effects. RESULTS: One hundred twenty-six of 150 (84%) HCWs who volunteered for participation completed all four blood draws. Prevalence of seropositive HCWs based on positive Sars-CoV-2 IgG antibodies increased from 2% at baseline to 31% at 12 weeks but declined to 21% by 6 months. Forty-two percent (19/43) of the participants considered seropositive for Sars-CoV-2 IgG antibodies at any of the initial three blood draws converted to seronegative status at the 6-month follow-up. Eighty-seven percent (72/83) of participants who responded to a follow-up survey were willing to accept the COVID19 vaccine. Rates of acceptance did not differ by participant antibody status. Those that experienced symptoms with the first injection were more likely to have positive Sars-CoV-2 IgG antibodies (36.8% vs. 9.6%, p = .01). CONCLUSION: Sars-CoV-2 IgG antibodies wane over time and may not provide prolonged and robust immune protection. This underscores the importance of vaccination and continued research in this area while the COVID19 pandemic continues.

Contractions: Traditional concepts and their role in modern obstetrics.

Contractions are produced through a complex interplay of hormonal, mechanical, and electrical factors. In labor, contractions are measured using the Montevideo unit. Clinical considerations in labor wherein contraction assessment becomes paramount include the care of women whose labor is complicated by abnormal progress or tachysystole. In an era of obstetrics in which the high cesarean rate is a major issue of concern, there remain many questions as to how to best incorporate contraction monitoring into practice in order to optimize care. Technological advancement has led to the development on new modalities that can be used to study contraction physiology, and there may be an opportunity in the future to apply these methods for use in the clinical setting. This article also makes a case for the need to reevaluate the current measures of uterine contractile activity and the definition of contraction adequacy using updated definitions of normal labor progress.