PAM-free diagnostics with diverse type V CRISPR-Cas systems.

Type V CRISPR-Cas effectors have revolutionized molecular diagnostics by facilitating the detection of nucleic acid biomarkers. However, their dependence on the presence of protospacer adjacent motif (PAM) sites on the target double-stranded DNA (dsDNA) greatly limits their flexibility as diagnostic tools. Here we present a novel method named PICNIC that solves the PAM problem for CRISPR-based diagnostics with just a simple ∼10-min modification to contemporary CRISPR-detection protocols. Our method involves the separation of dsDNA into individual single-stranded DNA (ssDNA) strands through a high- temperature and high-pH treatment. We then detect the released ssDNA strands with diverse Cas12 enzymes in a PAM-free manner. We show the utility of PICNIC by successfully applying it for PAM-free detection with three different subtypes of the Cas12 family- Cas12a, Cas12b, and Cas12i. Notably, by combining PICNIC with a truncated 15-nucleotide spacer containing crRNA, we demonstrate PAM-independent detection of clinically important single- nucleotide polymorphisms with CRISPR. We apply this approach to detect the presence of a drug-resistant variant of HIV-1, specifically the K103N mutant, that lacks a PAM site in the vicinity of the mutation. Additionally, we successfully translate our approach to clinical samples by detecting and genotyping HCV-1a and HCV-1b variants with 100% specificity at a PAM-less site within the HCV genome. In summary, PICNIC is a simple yet groundbreaking method that enhances the flexibility and precision of CRISPR-Cas12-based diagnostics by eliminating the restriction of the PAM sequence.

Mining in space could spur sustainable growth.

Growth models with resources and environmental externalities typically assume that planet Earth is a closed economy. However, private firms like Blue Origin and SpaceX have reduced the cost of rocket launches by a factor of 20 over the last decade. What if these costs continue to decline, making mining from asteroids or the moon feasible? What would be the implications for economic growth and the environment? This paper provides stylized facts about cost trends, geology, and the environmental impact of mining on Earth and potentially in Space. We extend a neoclassical growth model to investigate the transition from mining on Earth to Space. We find that such a transition could potentially allow for continued growth of metal use, while limiting environmental and social costs on Earth. Acknowledging the high uncertainty around the topic, our paper provides a starting point for research on how Space mining could contribute to sustainable growth on Earth.

Management of Preterm Premature Rupture of Membranes: A Comparison of Inpatient and Outpatient Care.

OBJECTIVES: We sought to evaluate the safety of outpatient management of pregnancy complicated by preterm premature rupture of membranes (PPROM). STUDY DESIGN: We performed a retrospective cohort study of women with PPROM and a latency period of at least one week in one provincial health region between January 2007 and December 2012. We evaluated pregnancy outcomes for 133 women whose cases were managed using specialized community care and compared these with outcomes of a similar group of 122 women whose cases were managed entirely in the hospital. The primary outcome measured was the difference in the latency period between the two groups. For categorical variable outcomes, data were analyzed using chi-square tests, and continuous variable outcomes were compared using t tests. RESULTS: The median latency period for inpatients was 11 days compared with 18 days for patients in the community (P < 0.001). The most common reason for delivery was spontaneous labour (57% of inpatients and 50% of outpatients). Rates of stillbirth and neonatal mortality were similar between the two groups (3% in the inpatient group and 4% in the outpatient group). Precipitous vaginal delivery of a preterm breech infant was associated with mortality. Umbilical cord pH was < 7.10 in 5% of the inpatient group and 3% of the outpatient group. Median Apgar scores were slightly higher among the outpatient group. CONCLUSION: The safety of outpatient management of appropriately selected patients with PPROM is comparable with the safety of in-hospital management. Patients with PPROM and a fetus in breech presentation may not be appropriate for outpatient management, especially prior to 28 weeks' gestation. The decision to manage a patient with PPROM on an outpatient basis must be made after careful evaluation, with a thorough discussion of the risks and benefits and with serial reassessment of patient suitability.

A rare case of antepartum spontaneous septostomy in a monochorionic diamniotic twin pregnancy.

Spontaneous septostomy in a monochorionic diamniotic twin pregnancy is a rare phenomenon. We present a case of monochorionic diamniotic twin pregnancy with an intact dividing membrane seen in the 1st half of the pregnancy. At 26 weeks, when she was assessed for preterm contractions, the dividing membrane was not documented, which suggested spontaneous septostomy. There had been no invasive procedures during the pregnancy. She subsequently delivered at 29 weeks, secondary to preterm labor. No dividing membrane was noticed at the time of caesarian section. Spontaneous septostomy can complicate the management of monochorionic diamniotic twins by creating a pseudomonoamniotic environment resulting in cord entanglement, and difficulty in the diagnosis and management of twin-twin transfusion syndrome. We believe that such a case should be managed as monochorionic monoamniotic twin gestation.

The Coffin-Lowry syndrome: a case report and review of the literature.

BACKGROUND: Prenatal ultrasound has afforded insights into many structural and syndromic fetal disorders. In this report, the ultrasound findings were of assistance when counselling a patient who presented with a history of Coffin-Lowry syndrome (CLS). CASE: A 39-year-old woman presented in the third trimester of pregnancy asking whether CLS could be diagnosed in utero. Three of her male offspring had been found to have this syndrome in childhood. Ultrasound assessment of the fetus was able to confirm female sex, which provided direction for counselling. An additional finding was of short and stubby digits, which have been well described as part of this syndrome. This information provided direction for pediatric management. CONCLUSION: CLS is a rare syndrome that is typically diagnosed in childhood. To our knowledge, this is the first report of a case in which prenatal ultrasound provided assistance for counselling before delivery.

The predictive value of 18 and 22 week uterine artery Doppler in patients with low first trimester maternal serum PAPP-A.

OBJECTIVE: To determine if the addition of uterine artery (UA) Doppler pulsatility index (PI) at 18 and 22 weeks of gestation improves the predictive accuracy of low first trimester pregnancy associated plasma protein A (PAPP-A) in the detection of adverse obstetrical outcomes. METHODS: This was a prospective interventional study. All women undergoing first trimester combined screening (FTS) at a single center, with a low maternal serum PAPP-A level (<0.4 MoM), were included. Patients underwent bilateral UA Doppler assessments at 18 and 22 weeks of gestation. A positive test was defined as a mean PI > 1.45. Primary outcomes were obtained from chart review, and logistic regression analysis was used to compare outcomes with positive and negative tests. Positive and negative predictive value, specificity and sensitivity were calculated. RESULTS: Between January and October 2007, 5359 women completed FTS. Among the low PAPP-A group (n = 289), 18 week UA Doppler was a significant predictor of low birth weight (OR = 2.28, p = 0.04) while 22 week UA Doppler significantly predicted preterm birth (OR = 12.6, p = 0.001), small for gestational age (OR = 8.24, p = 0.001) and low birth weight (OR = 2.28, p = 0.04). Test characteristics suggested improved positive and negative predictive value for Doppler at 22 versus 18 weeks for these outcomes. CONCLUSIONS: UA Doppler at 22 weeks is a useful adjunct in patients with low PAPP-A. However, a negative Doppler does not rule out all adverse outcomes and clinical judgment is advised in the management of these patients.

Peripartum hysterectomy: 1999 to 2006.

OBJECTIVE: To estimate the rate of peripartum hysterectomy over the last 8 years in Calgary, the primary indication for peripartum hysterectomy (defined as any hysterectomy performed within 24 hours of a delivery), and whether there was an increase in the rate of peripartum hysterectomy during that time. METHOD: Detailed chart review of all cases of peripartum hysterectomy, 1999-2006, including previous obstetric history, details of the index pregnancy, indications for peripartum hysterectomy, outcome of the hysterectomy, and infant morbidity. RESULTS: The overall rate of peripartum hysterectomy was 87 of 108,154 or 0.8 per 1,000 deliveries. The primary indications for hysterectomy were uterine atony (32 of 87, 37%) and suspected placenta accreta (29 of 87, 33%). After hysterectomy, 46 (53%) women were admitted to the intensive care unit. Women were discharged home after a mean 6-day length of stay. The rate of peripartum hysterectomy did not appear to increase over time. CONCLUSION: Our population-based study found that abnormal placentation is the main indication for peripartum hysterectomy. The most important step in prevention of major postpartum hemorrhage is recognizing and assessing women's risk, although even perfect management of hemorrhage cannot always prevent surgery.

Compliance with a perinatal prophylaxis policy for prevention of venous thromboembolism after caesarean section.

OBJECTIVE: To assess physician compliance, before and after a quality improvement intervention, with a regional policy on postpartum thromboprophylaxis following Caesarean section (CS), and to compare clinical outcomes (reduction of venous thromboembolism or increase in postpartum bleeding) between groups. METHODS: We performed a retrospective chart review of deliveries by CS, 404 prior to and 451 subsequent to a quality improvement intervention. All subjects were classified as being at either moderate or high risk for venous thromboembolism based on a risk-factor assessment, and warranted postpartum thromboprophylaxis according to the regional policy. Data regarding thromboembolism risk factors, postpartum thromboprophylaxis received, and clinical outcomes were recorded. RESULTS: Initial compliance with the regional policy was poor, but improved following the intervention. The use of intermittent pneumatic compression devices increased from 32% to 84% (P < 0.001), use of anticoagulation increased from 6.2% to 46% (P < 0.001), and full compliance with the policy increased from 1.7% to 30% (P < 0.001). Clinical outcomes were not significantly different between the groups. CONCLUSION: A quality improvement intervention markedly increased physician compliance with a regional policy on postpartum thromboprophylaxis among women at moderate to high risk of venous thromboembolism after CS. Adverse clinical outcomes were infrequent in this small study population.

Investigating adverse outcomes in obstetrics.

Investigation of adverse outcomes in health care requires a systematic and systemically oriented approach. This is true in obstetrics where, in Western countries such as Canada, adverse outcomes in the form of maternal mortality are rare. A model for such investigation is presented, based on answers to 3 questions: What? How? and Why? These questions correspond to Donabedian's 3 components of quality assurance: Outcome, Process, and Structure, respectively. Aspects of Reason's model of accidents are also included, in the form of "active failures" and "latent conditions." The latter are divided into 5 basic contributory factors, 4 of which are derived from Helmreich's model of human factors influencing behaviour in flight-crew environments. To illustrate its basic nature, the model is applied to a previously well-investigated air crash at Dryden, Ontario, and 3 obstetric cases of maternal mortality. Application of the model to the reactive investigation of close calls is discussed, as is application to the proactive interrogation of the system for the presence and nature of hazards that pose threats to safety.