Enzyme conformational alterations detected by partition column chromatography

In this paper, we demonstrate the ability of liquid-liquid partition chromatography (LLPC) to detect conformational alterations occurring in well-characterized enzymes. The conformational changes induced in dehydrogenases such as alcohol dehydrogenase (ADH), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), lactate dehydrogenases (LDH) and malate dehydrogenase (MDH) upon binding of ligand(s) were detectable by LLPC. The ligand-dependent equilibrium between two forms of citrate synthase (CS), glutamate-oxaloacetate transaminase (GOT), hexokinase (HK) and 3-phosphoglycerate kinase (PGK) could also be demonstrated. Furthermore, different conformational forms of some of the apoenzymes could also be detected and separated by LLPC. The results obtained here are discussed in relation to those obtained by other methods.     

SveDem,the Swedish Dementia Registry – A Tool for Improving the Quality of Diagnostics,Treatment and Care of Dementia Patients in Clinical Practice

BackgroundThe Swedish Dementia Registry (SveDem) was developed with the aim to improve the quality of diagnostic work-up, treatment and care of patients with dementia disorders in Sweden.MethodsSveDem is an internet based quality registry where several indicators can be followed over time. It includes information about the diagnostic work-up, medical treatment and community support (www.svedem.se). The patients are diagnosed and followed-up yearly in specialist units, primary care centres or in nursing homes.ResultsThe database was initiated in May 2007 and covers almost all of Sweden. There were 28 722 patients registered with a mean age of 79.3 years during 2007–2012. Each participating unit obtains continuous online statistics from its own registrations and they can be compared with regional and national data. A report from SveDem is published yearly to inform medical and care professionals as well as political and administrative decision-makers about the current quality of diagnostics, treatment and care of patients with dementia disorders in Sweden.ConclusionSveDem provides knowledge about current dementia care in Sweden and serves as a framework for ensuring the quality of diagnostics, treatment and care across the country. It also reflects changes in quality dementia care over time. Data from SveDem can be used to further develop the national guidelines for dementia and to generate new research hypotheses.     

Separating parental and treatment contributions to perinatal health after fresh and frozen embryo transfer in assisted reproduction: A cohort study with within-sibship analysis

BackgroundCompared to naturally conceived children, adverse perinatal outcomes are more common among children born after assisted reproductive technology with fresh embryo transfer (fresh-ET) or frozen embryo transfer (frozen-ET). However, most previous studies could not adequately control for family confounding factors such as subfertility. We compared birth size and duration of pregnancy among infants born after fresh-ET or frozen-ET versus natural conception, using a within-sibship design to account for confounding by maternal factors.Methods and findingsThis registry-based cohort study with nationwide data from Denmark (1994–2014), Norway (1988–2015), and Sweden (1988–2015) consisted of 4,510,790 live-born singletons, 4,414,703 from natural conception, 78,095 from fresh-ET, and 17,990 from frozen-ET. We identified 33,056 offspring sibling groups with the same mother, conceived by at least 2 different conception methods. Outcomes were mean birthweight, small and large for gestational age, mean gestational age, preterm (<37 weeks, versus ≥37), and very preterm birth (<32 weeks, versus ≥32). Singletons born after fresh-ET had lower mean birthweight (−51 g, 95% CI −58 to −45, p < 0.001) and increased odds of small for gestational age (odds ratio [OR] 1.20, 95% CI 1.08 to 1.34, p < 0.001), while those born after frozen-ET had higher mean birthweight (82 g, 95% CI 70 to 94, p < 0.001) and increased odds of large for gestational age (OR 1.84, 95% CI 1.56 to 2.17, p < 0.001), compared to naturally conceived siblings. Conventional population analyses gave similar results. Compared to naturally conceived siblings, mean gestational age was lower after fresh-ET (−1.0 days, 95% CI −1.2 to −0.8, p < 0.001), but not after frozen-ET (0.3 days, 95% CI 0.0 to 0.6, p = 0.028). There were increased odds of preterm birth after fresh-ET (OR 1.27, 95% CI 1.17 to 1.37, p < 0.001), and in most models after frozen-ET, versus naturally conceived siblings, with somewhat stronger associations in population analyses. For very preterm birth, population analyses showed increased odds for both fresh-ET (OR 2.03, 95% CI 1.90 to 2.12, p < 0.001) and frozen-ET (OR 1.66, 95% CI 1.42 to 1.94, p < 0.001) compared with natural conception, but results were notably attenuated within siblings (OR 1.18, 95% CI 1.0 to 1.41, p = 0.059, and OR 0.92, 95% CI 0.67 to 1.27, p = 0.6, for fresh-ET and frozen-ET, respectively). Sensitivity analyses in full siblings, in siblings born within 3-year interval, by birth order, and restricting to single embryo transfers and blastocyst transfers were consistent with the main analyses. Main limitations were high proportions of missing data on maternal body mass index and smoking.ConclusionsWe found that infants conceived by fresh-ET had lower birthweight and increased odds of small for gestational age, and those conceived by frozen-ET had higher birthweight and increased odds of large for gestational age. Conception by either fresh-ET or frozen-ET was associated with increased odds of preterm birth. That these findings were observed within siblings, as well as in conventional multivariable population analyses, reduces the likelihood that they are explained by confounding or selection bias.Trial registrationClinicalTrials.gov ISRCTN11780826.

Kjersti Westvik-Johari and co-workers report on perinatal outcomes following fresh and frozen embryo transfer.     

Cardiovascular disease,obesity, and type 2 diabetes in children born after assisted reproductive technology: A population-based cohort study

BackgroundSome earlier studies have found indications of significant changes in cardiometabolic risk factors in children born after assisted reproductive technology (ART). Most of these studies are based on small cohorts with high risk of selection bias. In this study, we compared the risk of cardiovascular disease, obesity, and type 2 diabetes between singleton children born after ART and singleton children born after spontaneous conception (SC).Methods and findingsThis was a large population-based cohort study of individuals born in Norway, Sweden, Finland, and Denmark between 1984 and 2015. Data were obtained from national ART and medical birth registers and cross-linked with data from national patient registers and other population-based registers in the respective countries. In total, 122,429 children born after ART and 7,574,685 children born after SC were included. Mean (SD) maternal age was 33.9 (4.3) years for ART and 29.7 (5.2) for SC, 67.7% versus 41.8% were primiparous, and 45.2% versus 32.1% had more than 12 years of education. Preterm birth (<37 weeks 0 days) occurred in 7.9% of children born after ART and 4.8% in children born after SC, and 5.7% versus 3.3% had a low birth weight (<2,500 g). Mean (SD) follow-up time was 8.6 (6.2) years for children born after ART and 14.0 (8.6) years for children born after SC. In total, 135 (0.11%), 645 (0.65%), and 18 (0.01%) children born after ART were diagnosed with cardiovascular disease (ischemic heart disease, cardiomyopathy, heart failure, or cerebrovascular disease), obesity or type 2 diabetes, respectively. The corresponding values were 10,702 (0.14%), 30,308 (0.74%), and 2,919 (0.04%) for children born after SC. In the unadjusted analysis, children born after ART had a significantly higher risk of any cardiovascular disease (hazard ratio [HR] 1.24; 95% CI 1.04–1.48; p = 0.02), obesity (HR 1.13; 95% CI 1.05–1.23; p = 0.002), and type 2 diabetes (HR 1.71; 95% CI 1.08–2.73; p = 0.02). After adjustment, there was no significant difference between children born after ART and children born after SC for any cardiovascular disease (adjusted HR [aHR]1.02; 95% CI 0.86–1.22; p = 0.80) or type 2 diabetes (aHR 1.31; 95% CI 0.82–2.09; p = 0.25). For any cardiovascular disease, the 95% CI was reasonably narrow, excluding effects of a substantial magnitude, while the 95% CI for type 2 diabetes was wide, not excluding clinically meaningful effects. For obesity, there was a small but significant increased risk among children born after ART (aHR 1.14; 95% CI 1.06–1.23; p = 0.001). Important limitations of the study were the relatively short follow-up time, the limited number of events for some outcomes, and that the outcome obesity is often not considered as a disease and therefore not caught by registers, likely leading to an underestimation of obesity in both children born after ART and children born after SC.ConclusionsIn this study, we observed no difference in the risk of cardiovascular disease or type 2 diabetes between children born after ART and children born after SC. For obesity, there was a small but significant increased risk for children born after ART.Trial registration numberISRCTN11780826.

Emma Norrman and co-workers study the health of children born with and without assisted reproductive technology.     

Cancer in children born after frozen-thawed embryo transfer: A cohort study

BackgroundThe aim was to investigate whether children born after assisted reproduction technology (ART), particularly after frozen-thawed embryo transfer (FET), are at higher risk of childhood cancer than children born after fresh embryo transfer and spontaneous conception.Methods and findingsWe performed a registry-based cohort study using data from the 4 Nordic countries: Denmark, Finland, Norway, and Sweden. The study included 7,944,248 children, out of whom 171,774 children were born after use of ART (2.2%) and 7,772,474 children were born after spontaneous conception, representing all children born between the years 1994 to 2014 in Denmark, 1990 to 2014 in Finland, 1984 to 2015 in Norway, and 1985 to 2015 in Sweden. Rates for any cancer and specific cancer groups in children born after each conception method were determined by cross-linking national ART registry data with national cancer and health data registries and population registries. We used Cox proportional hazards models to estimate the risk of any cancer, with age as the time scale.After a mean follow-up of 9.9 and 12.5 years, the incidence rate (IR) of cancer before age 18 years was 19.3/100,000 person-years for children born after ART (329 cases) and 16.7/100,000 person-years for children born after spontaneous conception (16,184 cases). Adjusted hazard ratio (aHR) was 1.08, 95% confidence interval (CI) 0.96 to 1.21, p = 0.18. Adjustment was performed for sex, plurality, year of birth, country of birth, maternal age at birth, and parity. Children born after FET had a higher risk of cancer (48 cases; IR 30.1/100,000 person-years) compared to both fresh embryo transfer (IR 18.8/100,000 person-years), aHR 1.59, 95% CI 1.15 to 2.20, p = 0.005, and spontaneous conception, aHR 1.65, 95% CI 1.24 to 2.19, p = 0.001. Adjustment either for macrosomia, birth weight, or major birth defects attenuated the association marginally. Higher risks of epithelial tumors and melanoma after any assisted reproductive method and of leukemia after FET were observed.The main limitation of this study is the small number of children with cancer in the FET group.ConclusionsChildren born after FET had a higher risk of childhood cancer than children born after fresh embryo transfer and spontaneous conception. The results should be interpreted cautiously based on the small number of children with cancer, but the findings raise concerns considering the increasing use of FET, in particular freeze-all strategies without clear medical indications.Trial registrationTrial registration number: ISRCTN 11780826.

Nona Sargisian and colleagues investigate the risk of childhood cancer in children born after Frozen-Thawed Embryo Transfer in Denmark, Finland, Norway, and Sweden.     

Founder mutations characterise the mutation panorama in 200 Swedish index cases referred for Long QT syndrome genetic testing

Background

Hypertension is one of the leading causes of cardiovascular disease (CVD). A range of antihypertensive drugs exists, and their prices vary widely mainly due to patent rights. The objective of this study was to explore the cost-effectiveness of different generic antihypertensive drugs as first, second and third choice for primary prevention of cardiovascular disease.

Methods

We used the Norwegian Cardiovascular Disease model (NorCaD) to simulate the cardiovascular life of patients from hypertension without symptoms until they were all dead or 100 years old. The risk of CVD events and costs were based on recent Norwegian sources.

Results

In single-drug treatment, all antihypertensives are cost-effective compared to no drug treatment. In the base-case analysis, the first, second and third choice of antihypertensive were calcium channel blocker, thiazide and angiotensin-converting enzyme inhibitor. However the sensitivity and scenario analyses indicated considerable uncertainty in that angiotensin receptor blockers as well as, angiotensin-converting enzyme inhibitors, beta blockers and thiazides could be the most cost-effective antihypertensive drugs.

Conclusions

Generic antihypertensives are cost-effective in a wide range of risk groups. There is considerable uncertainty, however, regarding which drug is the most cost-effective.     

Induction of labour at 41 weeks or expectant management until 42 weeks: A systematic review and an individual participant data meta-analysis of randomised trials

BackgroundThe risk of perinatal death and severe neonatal morbidity increases gradually after 41 weeks of pregnancy. Several randomised controlled trials (RCTs) have assessed if induction of labour (IOL) in uncomplicated pregnancies at 41 weeks will improve perinatal outcomes. We performed an individual participant data meta-analysis (IPD-MA) on this subject.Methods and findingsWe searched PubMed, Excerpta Medica dataBASE (Embase), The Cochrane Library, Cumulative Index of Nursing and Allied Health Literature (CINAHL), and PsycINFO on February 21, 2020 for RCTs comparing IOL at 41 weeks with expectant management until 42 weeks in women with uncomplicated pregnancies. Individual participant data (IPD) were sought from eligible RCTs. Primary outcome was a composite of severe adverse perinatal outcomes: mortality and severe neonatal morbidity. Additional outcomes included neonatal admission, mode of delivery, perineal lacerations, and postpartum haemorrhage. Prespecified subgroup analyses were conducted for parity (nulliparous/multiparous), maternal age (<35/≥35 years), and body mass index (BMI) (<30/≥30). Aggregate data meta-analysis (MA) was performed to include data from RCTs for which IPD was not available.From 89 full-text articles, we identified three eligible RCTs (n = 5,161), and two contributed with IPD (n = 4,561). Baseline characteristics were similar between the groups regarding age, parity, BMI, and higher level of education. IOL resulted overall in a decrease of severe adverse perinatal outcome (0.4% [10/2,281] versus 1.0% [23/2,280]; relative risk [RR] 0.43 [95% confidence interval [CI] 0.21 to 0.91], p-value 0.027, risk difference [RD] −57/10,000 [95% CI −106/10,000 to −8/10,000], I² 0%). The number needed to treat (NNT) was 175 (95% CI 94 to 1,267).Perinatal deaths occurred in one (<0.1%) versus eight (0.4%) pregnancies (Peto odds ratio [OR] 0.21 [95% CI 0.06 to 0.78], p-value 0.019, RD −31/10,000, [95% CI −56/10,000 to −5/10,000], I² 0%, NNT 326, [95% CI 177 to 2,014]) and admission to a neonatal care unit ≥4 days occurred in 1.1% (24/2,280) versus 1.9% (46/2,273), (RR 0.52 [95% CI 0.32 to 0.85], p-value 0.009, RD −97/10,000 [95% CI −169/10,000 to −26/10,000], I² 0%, NNT 103 [95% CI 59 to 385]). There was no difference in the rate of cesarean delivery (10.5% versus 10.7%; RR 0.98, [95% CI 0.83 to 1.16], p-value 0.81) nor in other important perinatal, delivery, and maternal outcomes. MA on aggregate data showed similar results.Prespecified subgroup analyses for the primary outcome showed a significant difference in the treatment effect (p = 0.01 for interaction) for parity, but not for maternal age or BMI. The risk of severe adverse perinatal outcome was decreased for nulliparous women in the IOL group (0.3% [4/1,219] versus 1.6% [20/1,264]; RR 0.20 [95% CI 0.07 to 0.60], p-value 0.004, RD −127/10,000, [95% CI −204/10,000 to −50/10,000], I² 0%, NNT 79 [95% CI 49 to 201]) but not for multiparous women (0.6% [6/1,219] versus 0.3% [3/1,264]; RR 1.59 [95% CI 0.15 to 17.30], p-value 0.35, RD 27/10,000, [95% CI −29/10,000 to 84/10,000], I² 55%).A limitation of this IPD-MA was the risk of overestimation of the effect on perinatal mortality due to early stopping of the largest included trial for safety reasons after the advice of the Data and Safety Monitoring Board. Furthermore, only two RCTs were eligible for the IPD-MA; thus, the possibility to assess severe adverse neonatal outcomes with few events was limited.ConclusionsIn this study, we found that, overall, IOL at 41 weeks improved perinatal outcome compared with expectant management until 42 weeks without increasing the cesarean delivery rate. This benefit is shown only in nulliparous women, whereas for multiparous women, the incidence of mortality and morbidity was too low to demonstrate any effect. The magnitude of risk reduction of perinatal mortality remains uncertain. Women with pregnancies approaching 41 weeks should be informed on the risk differences according to parity so that they are able to make an informed choice for IOL at 41 weeks or expectant management until 42 weeks.Study Registration: PROSPERO CRD42020163174

Mårten Alkmark and co-workers report on a meta-analysis of randomized trials of labour induction at 41 weeks'' gestation as compared with expectant management until 42 weeks.     

Interaction of the hepatic receptor protein for 2,3,7,8-tetrachlorodibenzo-p-dioxin with DNA

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) binds to a specific, high-affinity, low-capacity protein in rat liver cytosol. The TCDD-receptor complex is a large molecule with a Stokes radius of 6.6 nm as determined by gel filtration on calibrated columns. The receptor complex sediments at 5.0 S on glycerol gradients. The calculated molecular weight from the physical parameters was 136 000 and the frictional ratio 1.79.The TCDD-receptor complex binds to DNA-cellulose without preceding heat activation or incubation at high ionic strength. The receptor must first bind TCDD before it can interact with DNA. The DNA-binding ability can be removed from the TCDD receptor by limited proteolysis with trypsin. This treatment does not affect the TCDD-binding site of the receptor. The proteolytic fragment of the TCDD-receptor complex containing the TCDD-binding site but not the ability to bind to DNA appears to be approximately the same size as the native receptor, as judged from chromatography of Sepharose CL-6B and glycerol gradient centrifugation.