BLM–DNA2–RPA–MRN and EXO1–BLM–RPA–MRN constitute two DNA end resection machineries for human DNA break repair

Repair of dsDNA breaks requires processing to produce 3′-terminated ssDNA. We biochemically reconstituted DNA end resection using purified human proteins: Bloom helicase (BLM); DNA2 helicase/nuclease; Exonuclease 1 (EXO1); the complex comprising MRE11, RAD50, and NBS1 (MRN); and Replication protein A (RPA). Resection occurs via two routes. In one, BLM and DNA2 physically and specifically interact to resect DNA in a process that is ATP-dependent and requires BLM helicase and DNA2 nuclease functions. RPA is essential for both DNA unwinding by BLM and enforcing 5′ → 3′ resection polarity by DNA2. MRN accelerates processing by recruiting BLM to the end. In the other, EXO1 resects the DNA and is stimulated by BLM, MRN, and RPA. BLM increases the affinity of EXO1 for ends, and MRN recruits and enhances the processivity of EXO1. Our results establish two of the core machineries that initiate recombinational DNA repair in human cells

DNA end resection by Dna2–Sgs1–RPA and its stimulation by Top3–Rmi1 and Mre11–Rad50–Xrs2

The repair of DNA double-strand breaks (DSBs) by homologous recombination requires processing of broken ends. For repair to start, the DSB must first be resected to generate a 3′-single-stranded DNA (ssDNA) overhang, which becomes a substrate for the DNA strand exchange protein, Rad51 (ref. 1). Genetic studies have implicated a multitude of proteins in the process, including helicases, nucleases and topoisomerases. Here we biochemically reconstitute elements of the resection process and reveal that it requires the nuclease Dna2, the RecQ-family helicase Sgs1 and the ssDNA-binding protein replication protein-A (RPA). We establish that Dna2, Sgs1 and RPA constitute a minimal protein complex capable of DNA resection in vitro. Sgs1 helicase unwinds the DNA to produce an intermediate that is digested by Dna2, and RPA stimulates DNA unwinding by Sgs1 in a species-specific manner. Interestingly, RPA is also required both to direct Dna2 nucleolytic activity to the 5′-terminated strand of the DNA break and to inhibit 3′ to 5′ degradation by Dna2, actions that generate and protect the 3′-ssDNA overhang, respectively. In addition to this core machinery, we establish that both the topoisomerase 3 (Top3) and Rmi1 complex and the Mre11–Rad50–Xrs2 complex (MRX) have important roles as stimulatory components. Stimulation of end resection by the Top3–Rmi1 heterodimer and the MRX proteins is by complex formation with Sgs1 (refs 5, 6), which unexpectedly stimulates DNA unwinding. We suggest that Top3–Rmi1 and MRX are important for recruitment of the Sgs1–Dna2 complex to DSBs. Our experiments provide a mechanistic framework for understanding the initial steps of recombinational DNA repair in eukaryotes

Dependence of peculiar velocity on the host properties of the gravitational wave sources and its impact on the measurement of Hubble constant

Accurate measurement of the Hubble constant from standard sirens such as the gravitational wave (GW) sources with electromagnetic counterparts relies on the robust peculiar velocity correction of the redshift of the host galaxy. We show in this work that the peculiar velocity of the host galaxies exhibits a correlation with the properties of the host galaxy primarily such as its stellar mass and this correlation also evolves with redshift. As the galaxies of higher stellar mass tend to form in galaxies with higher halo masses which are located in spatial regions having a non-linear fluctuation in the density field of the matter distribution, the root mean square (RMS) peculiar velocity of more massive galaxies is higher. As a result, depending on the formation channel of the binary compact objects, the peculiar velocity contamination to the galaxies will be different. The variation in the peculiar velocity of the host galaxies can lead to a significant variation in the estimation of the Hubble constant inferred using sources such as Binary Neutron Stars (BNSs). For the network of GW detectors such as LIGO-Virgo-KAGRA (LVK), LVK+LIGO-India, and Cosmic Explorer+Einstein Telescope, the variation in the precision of Hubble constant inferred from 10 bright siren events can vary from $\sim 5.4 - 6\%$, $\sim 4.5 - 5.3\%$ and $\sim 1.1 - 2.7\%$ respectively. The impact of such a correlation between peculiar velocity and stellar mass on the inference of the Hubble constant is not only limited to GW sources but also applicable to type-Ia supernovae.Comment: 14 pages, 11 figures. Accepted for publication in MNRA

Influence of Hand Anthropometry and Nutrient Intake on Hand Grip Strength: A Correlational Study Among Young Indian Badminton Players

Badminton is a fast shuttle-racquet game, which requires adequate endurance and agility for hitting shots. For consistent and superior performances, players need to develop decent nutritional status and tremendous physical fitness. The present study concerns with the effect of anthropometric indices and nutritional profiles on arm strength for racquet gripping. Adolescent male (N=100) and female (N=100) badminton players aged 10 to 15 years were selected from Nagpur, India, and arm anthropometric indices and skeletal muscles of the players were determined by tape and bioelectrical impedance analyzer respectively. Muscle growing macronutrient (protein) and skeletal developing micronutrients (calcium and phosphorus) were calculated from dietary data for consecutive 3 days by the 24-hour dietary recall method. Arm strength was appraised from the hand grip strength test. Statistically, the assessed data were tested at 1% and 5% significance levels. Pearson correlation coefficients were derived. All the age groups possessed substantially shorter arm lengths (2.41-15.43%) than reference standards. Older groups appeared to have greater arm circumferences (1.00-3.92 cm) than younger groups. Overall, boys showed elevated skeletal muscles (6.69% and 8.29%) than girls. Dietary protein and phosphorus ingestion were significantly higher (45.42-90.88% and 16.18-40.62%) than recommended dietary allowances (RDAs). Calcium intake (23.26-28.48%) was below the RDA. Older male players performed under excellent grade (38%) in the hand grip strength test, depicting masculine supremacy. Positive correlations (r= 0.0710 to 0.5947) between arm anthropometry and nutrient intake with grip strength proved their affirmative effects on delivering various explosive shots, which can enhance the performance level of emerging young players

Comparative evaluation of two commonly administered regimens of mifepristone and misoprostol for first trimester abortion

Background: The objective of this study was to compare and evaluate the efficacy of two commonly administered regimens as per existing guidelines of Ministry of Health and Family Welfare for Outpatient MTP services. This study is aimed at evaluation of subjective and objective stastical benefits and side effects in performance of first trimester abortion on OPD basis in popularly used drugs as advised by MOHFW by different routes of administration. The drugs used were Tab Mifepristone (RU – 486) and Tab Misoprostol.Methods: This prospective randomized study was conducted in Out Patient Department of Obstetrics and Gynaecology in a tertiary care hospital over a period of 1 year after due clearance was obtained from Ethical Committee. This was prospective study involving 400 ladies reporting for Outpatient MTP services within the given time period as per existing guidelines at a tertiary care hospital. Patients were assessed at the end of 7, 15and 56 days, the mean age of the patients was 24.5±0.5 and 33±1 years and treatment duration was an average of 3 days with follow up for 15 days post administration. Few cases of failure required a follow up of approximately 56 days. All patients were on follow up for a period of 3 months for determination of menstrual irregularities and contraception management.Results: Between the 2 groups, in the sublingual Misoprostol group 100% aborted successfully at the end of 56 days. Whereas in the vaginal Misoprostol group 99% aborted successfully at the end of 56 days, only two patients requiring MVA as an OPD procedure.Conclusions: Patients were assessed at the end of 7, 15 and 56 days and between both the groups; Mifepristone with administration of misoprostol sublingually showed better success rate in completion of procedure, quicker action with better patient satisfaction and acceptance compared to conventional administration of Mifepristone and vaginal administration of misoprostol. Misoprostol administered sublingually under medical supervision is a superior, faster abortificient and has lesser incidence of Retained Products of Conception (RPOC) or need for Suction & Evacuation (S&E) as compared to vaginal route. Side effects observed need more evaluation with larger sample size to be statistically significant

Ormeloxifene in the management of dysfunctional uterine bleeding

Background: Dysfunctional Uterine Bleeding (DUB), is the commonest cause of Abnormal Uterine Bleeding (AUB). It causes morbidity, anaemia, and unnecessary hysterectomies in women of fertile age group. This study attempts to study efficacy of medical management especially Selective Estrogen Receptor Modulator (SERM) namely Ormeloxefine (ORM) (Sevista®) in Perimenopausal women. Ormeloxifene was marketed in India for contraception under brand names Centron, Saheli, Choice-7, Novex and Novex-DS. It’s a benzopyran derivative also known as Centchroman which causes asynchronousity between ovulation and menstrual cycles possibly because of both estrogenic and anti-estrogenic actions. It has been known to cause delay in ovulation in clinical trials; however, majority have been unaffected. It causes delay in proliferation of endometrium thereby causing asynchronous cycles. It also improves motility of ciliary lining of Fallopian tubes thereby reducing the chances of implantation of fertilized egg.  Methods: This study is aimed at evaluation of subjective and objective stastical benefits and side effects in treatment of DUB in perimenopausal age group with ORM and commonly used 19 nortestosterone compound (progesterone); Norethisterone (NET).Results: Primary outcome were analyzed at the end of every 3 months and at the end of one year finally. Secondary outcomes of the study in each arm were also assessed. There was stastically significant increase in Hb and stastically significant decrease in ET. Data analysis was done for variables in each arm by t-test to estimate the mean, median, range P and t value for a conclusion. Differences were taken as significant when P<0.05.Conclusions: ORM is a safe, cost effective, non-steroidal, non-hormonal drug with convenient dosage and better compliance for medical management of perimenopausal DUB with minimum focal pathology. Side effects observed need more evaluation with larger sample size to be statistically significant

Spot urinary albumin creatinine ratio as a predictor of preeclampsia and dilemma in clinical interpretation

Background: The objective of this study was to evaluate the efficacy of spot urinary albumin creatinine ratio (UACR) as a predictor of preeclampsia and dilemma faced by clinicians in interpretation of lab values expressed in different units, lack of standardization and its further ramifications in long term follow up and prevention of complications of preeclampsia. Wide variation for estimation of UACR leads to confusion in practice guidelines and its interpretation as single International practical information regarding laboratory measurements, calculation, reporting and interpretation doesn’t exist. This prospective randomized study was conducted in Out Patient Department of Obstetrics and Gynaecology in a tertiary care hospital over a period of 1 year after due clearance was obtained from Ethical Committee.Methods: This was prospective study involving 400 ladies reporting for Outpatient ANC services within the given time period as per existing guidelines at a tertiary care hospital. Patients were assessed at first booking visit at 18-20 weeks, and thereafter based on clinical and haematological findings, severity of disease more frequently if desired and were admitted in case of imminent eclampsia. The mean age of the patients was 20.5±0.5 and 24.5±0.5 years and treatment duration were till successful delivery and 06 weeks postpartum for persistent microalbuminuria and exclusion of underlying medical cause for Hypertension. Fetomaternal morbidity and mortality was not a criterion of exclusion.Results: Compared with 24-hour urinary protein excretion, the spot UACR may be a simple, convenient, and accurate indicator of significant proteinuria and future complications in women with preeclampsia with proper and intensive clinical follow up and intervention to prevent feto maternal morbidity and mortality. A strong correlation was evident between spot UACR with high sensitivity and specificity.Conclusions: UACR measurement is a simple, quick, and reasonably reliable method for prediction and assessment of severity of preeclampsia. Spot UACR correlates better than spot UPCR to 24-hour urinary protein excretion to the severity of disease and as predictor of severity of disease

The menace of caesarean scar pregnancy: a management challenge in modern obstetrics

Background: With the increasing caesarean section rates a new challenging evil of caesarean scar pregnancy (CSPs) has emerged. As a variant of ectopic pregnancy caesarean scar pregnancy is the rarest of all. Diagnosis and management of CSP can be challenging especially when there are no early symptoms and even lessor index of suspicion.  Objective of this endeavour was to present one institute experience of management of caesarean scar pregnancies.Methods: This are a retrospective analysis of women admitted with CSP. Detailed history, investigation, management protocols and complications were noted.Results: Of the total cases maximum women (60%) had history of previous two caesarean section. 90 % of cases were managed successfully with intra-sac or systemic methotrexate, and surgical evacuation with Foley’s catheter tamponade, only two women needed hysterectomy for uncontrolled bleeding.Conclusions: Caesarean scar pregnancy is a diagnostic and management challenge in modern obstetrics. Early ultrasound diagnosis helps in planning a successful medical treatment and serves to preserve uterus and fertility. Treatment with transabdominal intra-sac methotrexate and Foley’s catheter for tamponade is safe and effective method of treating CSPs

Prognostic significance of cerebro-placental ratio in predicting perinatal

Background: Cerebro-placental ratio (CPR), measured by Ultrasound Doppler velocimetry in pregnancy, has gained much attention in recent years as an important tool in predicting perinatal outcomes. The study aimed to calculate the cerebro-placental ratio and correlateit with perinatal outcome in terms of intrapartum fetal heart variation, meconium staining of liquor, mode of delivery, Apgar score at birth, and NICU admissions. Methods: It was hospital-based prospective cross-sectional study on 119 pregnant women with high-risk pregnancies. All women had doppler velocimetry ultrasound, and cerebro-placental ration was calculated. Perinatal outcome was noted in terms of FHR variability in labor, Meconium staining of liquor, Apgar score and need for NICU admission. Results: Out of the total of 119 women, 88 women had CPR &gt;1.08 and 31 women had CPR of &lt;1.08. Meconium staining of liquor, low Apgar score, and NICU admission was mound in significantly more babies with low CPR. Conclusions: CPR has a good prognostic value in predicting many adverse perinatal outcomes

DNA resection in eukaryotes: deciding how to fix the break

DNA double-strand breaks are repaired by different mechanisms, including homologous recombination and nonhomologous end-joining. DNA-end resection, the first step in recombination, is a key step that contributes to the choice of DSB repair. Resection, an evolutionarily conserved process that generates single-stranded DNA, is linked to checkpoint activation and is critical for survival. Failure to regulate and execute this process results in defective recombination and can contribute to human disease. Here, I review recent findings on the mechanisms of resection in eukaryotes, from yeast to vertebrates, provide insights into the regulatory strategies that control it, and highlight the consequences of both its impairment and its deregulation