Statistical analysis plan for the Stroke Oxygen Study (SO₂S): a multi-center randomized controlled trial to assess whether routine oxygen supplementation in the first 72 hours after a stroke improves long-term outcome.

BACKGROUND: The Stroke Oxygen Study (SO₂S) is a multi-center randomized controlled trial of oxygen supplementation in patients with acute stroke. The main hypothesis for the trial is that fixed-dose oxygen treatment during the first 3 days after an acute stroke improves outcome. The secondary hypothesis is that restricting oxygen supplementation to night time only is more effective than continuous supplementation. This paper describes the statistical analysis plan for the study. METHODS AND DESIGN: Patients (n = 8000) are randomized to three groups: (1) continuous oxygen supplementation for 72 hours; (2) nocturnal oxygen supplementation for three nights; and (3) no routine oxygen supplementation. Outcomes are recorded at 7 days, 90 days, 6 months, and 12 months. The primary outcome measure is the modified Rankin scale at 90 days. Data will be analyzed according to the intention-to-treat principle. Methods of statistical analysis are described, including the handling of missing data, the covariates used in adjusted analyses, planned subgroups analyses, and planned sensitivity analyses. TRIAL REGISTRATION: This trial is registered with the ISRCTN register, number ISRCTN52416964 (30 September 2005)

Dysregulation of the intrinsic apoptotic pathway mediates megakaryocytic hyperplasia in myeloproliferative neoplasms

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Does undertaking an intercalated BSc influence first clinical year exam results at a London medical school?

Background: Intercalated BScs (iBScs) are an optional part of the medical school curriculum in many Universities. Does undertaking an iBSc influence subsequent student performance? Previous studies addressing this question have been flawed by iBSc students being highly selected. This study looks at data from medical students where there is a compulsory iBSc for non-graduates. Our aim was to see whether there was any difference in performance between students who took an iBSc before or after their third year (first clinical year) exams.Methods: A multivariable analysis was performed to compare the third year results of students at one London medical school who had or had not completed their iBSc by the start of this year (n = 276). A general linear model was applied to adjust for differences between the two groups in terms of potential confounders (age, sex, nationality and baseline performance).Results: The results of third year summative exams for 276 students were analysed (184 students with an iBSc and 92 without). Unadjusted analysis showed students who took an iBSc before their third year achieved significantly higher end of year marks than those who did not with a mean score difference of 4.4 (0.9 to 7.9 95% CI, p = 0.01). (overall mean score 238.4 "completed iBSc" students versus 234.0 "not completed", range 145.2 - 272.3 out of 300). There was however a significant difference between the two groups in their prior second year exam marks with those choosing to intercalate before their third year having higher marks. Adjusting for this, the difference in overall exam scores was no longer significant with a mean score difference of 1.4 (-4.9 to +7.7 95% CI, p = 0.66). (overall mean score 238.0 "completed iBSc" students versus 236.5 "not completed").Conclusions: Once possible confounders are controlled for (age, sex, previous academic performance) undertaking an iBSc does not influence third year exam results. One explanation for this confounding in unadjusted results is that students who do better in their second year exams are more likely to take an iBSc before their third year

Centromere Protein B Null Mice are Mitotically and Meiotically Normal but Have Lower Body and Testis Weights

CENP-B is a constitutive centromere DNA-binding protein that is conserved in a number of mammalian species and in yeast. Despite this conservation, earlier cytological and indirect experimental studies have provided conflicting evidence concerning the role of this protein in mitosis. The requirement of this protein in meiosis has also not previously been described. To resolve these uncertainties, we used targeted disruption of the Cenpb gene in mouse to study the functional significance of this protein in mitosis and meiosis. Male and female Cenpb null mice have normal body weights at birth and at weaning, but these subsequently lag behind those of the heterozygous and wild-type animals. The weight and sperm content of the testes of Cenpb null mice are also significantly decreased. Otherwise, the animals appear developmentally and reproductively normal. Cytogenetic fluorescence-activated cell sorting and histological analyses of somatic and germline tissues revealed no abnormality. These results indicate that Cenpb is not essential for mitosis or meiosis, although the observed weight reduction raises the possibility that Cenpb deficiency may subtly affect some aspects of centromere assembly and function, and result in reduced rate of cell cycle progression, efficiency of microtubule capture, and/or chromosome movement. A model for a functional redundancy of this protein is presented

Management of patients with persistent medically unexplained symptoms: a descriptive study

Background: In 2013 the Dutch guideline for management of medically unexplained symptoms (MUS) was published. The aim of this study is to assess medical care for patients with persistent MUS as recorded in their electronic medical records, to investigate if this is in line with the national guideline for persistent MUS and whether there are changes in care over time. Methods: We conducted an observational study of adult primary care patients with MUS. Routinely recorded health care data were extracted from electronic medical records of patients participating in an ongoing randomised controlled trial in 30 general practices in the Netherlands. Data on general practitioners’ (GPs’) management strategies during MUS consultations were collected in a 5-year period for each patient prior. Management strategies were categorised according to the options offered in the Dutch guideline. Changes in management over time were analysed. Results: Data were collected from 1035 MUS consultations (77 patients). Beside history-taking, the most frequently used diagnostic strategies were physical examination (24.5%) and additional investigations by the GP (11.1%). Frequently used therapeutic strategies were prescribing medication (24.6%) and providing explanations (11.2%). As MUS symptoms persisted, GPs adjusted medication, discussed progress and scheduled follow-up appointments more frequently. The least frequently used strategies were exploration of all complaint dimensions (i.e. somatic, cognitive, emotional, behavioural and social) (3.5%) and referral to a psychologist (0.5%) or psychiatrist (0.1%). Conclusions: Management of Dutch GPs is partly in line with the Dutch guideline. Medication was possibly prescribed more frequently than recommended, whereas exploration of all complaint dimensions, shared problem definition and referral to mental health care were used less

Inflammatory and haematological markers in the maternal, umbilical cord and infant circulation in histological chorioamnionitis

BACKGROUND: The relationship between histological chorioamnionitis and haematological and biochemical markers in mothers and infants at delivery, and in infants postnatally, is incompletely characterised. These markers are widely used in the diagnosis of maternal and neonatal infection. Our objective was to investigate the effects of histological chorioamnionitis (HCA) on haematological and biochemical inflammatory markers in mothers and infants at delivery, and in infants post-delivery. METHODS: Two hundred and forty seven mothers, delivering 325 infants, were recruited at the only tertiary perinatal centre in Western Australia. Placentae were assessed for evidence of HCA using a semi-quantitative scoring system. Maternal high sensitivity C-reactive protein (hsCRP), procalcitonin, and umbilical cord hsCRP, procalcitonin, white cell count and absolute neutrophil count were measured at delivery. In infants where sepsis was clinically suspected, postnatal CRP, white cell count and absolute neutrophil count were measured up to 48 hours of age. The effect of HCA on maternal, cord and neonatal markers was evaluated by multivariable regression analysis. RESULTS: The median gestational age was 34 weeks and HCA was present in 26 of 247 (10.5%) placentae. Mothers whose pregnancies were complicated by HCA had higher hsCRP (median 26 (range 2-107) versus 5.6 (0-108) mg/L; P<0.001). Histological chorioamnionitis was associated with higher umbilical cord hsCRP (75(th) percentile 2.91 mg/L (range 0-63.9) versus 75(th) percentile 0 mg/L (0-45.6); P<0.001) and procalcitonin (median 0.293 (range 0.05-27.37) versus median 0.064 (range 0.01-5.24) ug/L; P<0.001), with a sustained increase in neonatal absolute neutrophil count (median 4.5 (0.1-26.4)x10(9)/L versus 3.0 (0.1-17.8)x10(9)/L), and CRP up to 48 hours post-partum (median 10 versus 6.5 mg/L) (P<0.05 for each). CONCLUSION: Histological chorioamnionitis is associated with modest systemic inflammation in maternal and cord blood. These systemic changes may increase postnatally, potentially undermining their utility in the diagnosis of early-onset neonatal infection