Developing a multivariable prediction model for functional outcome after reperfusion therapy for acute ischaemic stroke: study protocol for the Targeting Optimal Thrombolysis Outcomes (TOTO) multicentre cohort study.

INTRODUCTION:Intravenous thrombolysis (IVT) with recombinant tissue plasminogen activator (rt-PA) is the only approved pharmacological reperfusion therapy for acute ischaemic stroke. Despite population benefit, IVT is not equally effective in all patients, nor is it without significant risk. Uncertain treatment outcome prediction complicates patient treatment selection. This study will develop and validate predictive algorithms for IVT response, using clinical, radiological and blood-based biomarker measures. A secondary objective is to develop predictive algorithms for endovascular thrombectomy (EVT), which has been proven as an effective reperfusion therapy since study inception. METHODS AND ANALYSIS:The Targeting Optimal Thrombolysis Outcomes Study is a multicenter prospective cohort study of ischaemic stroke patients treated at participating Australian Stroke Centres with IVT and/or EVT. Patients undergo neuroimaging using multimodal CT or MRI at baseline with repeat neuroimaging 24 hours post-treatment. Baseline and follow-up blood samples are provided for research use. The primary outcome is good functional outcome at 90 days poststroke, defined as a modified Rankin Scale (mRS) Score of 0-2. Secondary outcomes are reperfusion, recanalisation, infarct core growth, change in stroke severity, poor functional outcome, excellent functional outcome and ordinal mRS at 90 days. Primary predictive models will be developed and validated in patients treated only with rt-PA. Models will be built using regression methods and include clinical variables, radiological measures from multimodal neuroimaging and blood-based biomarkers measured by mass spectrometry. Predictive accuracy will be quantified using c-statistics and R2. In secondary analyses, models will be developed in patients treated using EVT, with or without prior IVT, reflecting practice changes since original study design. ETHICS AND DISSEMINATION:Patients, or relatives when patients could not consent, provide written informed consent to participate. This study received approval from the Hunter New England Local Health District Human Research Ethics Committee (reference 14/10/15/4.02). Findings will be disseminated via peer-reviewed publications and conference presentations

Classical Effective Field Theory for Weak Ultra Relativistic Scattering

Inspired by the problem of Planckian scattering we describe a classical effective field theory for weak ultra relativistic scattering in which field propagation is instantaneous and transverse and the particles' equations of motion localize to the instant of passing. An analogy with the non-relativistic (post-Newtonian) approximation is stressed. The small parameter is identified and power counting rules are established. The theory is applied to reproduce the leading scattering angle for either a scalar interaction field or electro-magnetic or gravitational; to compute some subleading corrections, including the interaction duration; and to allow for non-zero masses. For the gravitational case we present an appropriate decomposition of the gravitational field onto the transverse plane together with its whole non-linear action. On the way we touch upon the relation with the eikonal approximation, some evidence for censorship of quantum gravity, and an algebraic ring structure on 2d Minkowski spacetime.Comment: 29 pages, 2 figures. v4: Duration of interaction is determined in Sec 4 and detailed in App C. Version accepted for publication in JHE

High-throughput identification of genotype-specific cancer vulnerabilities in mixtures of barcoded tumor cell lines.

Hundreds of genetically characterized cell lines are available for the discovery of genotype-specific cancer vulnerabilities. However, screening large numbers of compounds against large numbers of cell lines is currently impractical, and such experiments are often difficult to control. Here we report a method called PRISM that allows pooled screening of mixtures of cancer cell lines by labeling each cell line with 24-nucleotide barcodes. PRISM revealed the expected patterns of cell killing seen in conventional (unpooled) assays. In a screen of 102 cell lines across 8,400 compounds, PRISM led to the identification of BRD-7880 as a potent and highly specific inhibitor of aurora kinases B and C. Cell line pools also efficiently formed tumors as xenografts, and PRISM recapitulated the expected pattern of erlotinib sensitivity in vivo

Plasmin Generation Potential and Recanalization in Acute Ischaemic Stroke; an Observational Cohort Study of Stroke Biobank Samples.

Rationale: More than half of patients who receive thrombolysis for acute ischaemic stroke fail to recanalize. Elucidating biological factors which predict recanalization could identify therapeutic targets for increasing thrombolysis success. Hypothesis: We hypothesize that individual patient plasmin potential, as measured by in vitro response to recombinant tissue-type plasminogen activator (rt-PA), is a biomarker of rt-PA response, and that patients with greater plasmin response are more likely to recanalize early. Methods: This study will use historical samples from the Barcelona Stroke Thrombolysis Biobank, comprised of 350 pre-thrombolysis plasma samples from ischaemic stroke patients who received serial transcranial-Doppler (TCD) measurements before and after thrombolysis. The plasmin potential of each patient will be measured using the level of plasmin-antiplasmin complex (PAP) generated after in-vitro addition of rt-PA. Levels of antiplasmin, plasminogen, t-PA activity, and PAI-1 activity will also be determined. Association between plasmin potential variables and time to recanalization [assessed on serial TCD using the thrombolysis in brain ischemia (TIBI) score] will be assessed using Cox proportional hazards models, adjusted for potential confounders. Outcomes: The primary outcome will be time to recanalization detected by TCD (defined as TIBI ≥4). Secondary outcomes will be recanalization within 6-h and recanalization and/or haemorrhagic transformation at 24-h. This analysis will utilize an expanded cohort including ~120 patients from the Targeting Optimal Thrombolysis Outcomes (TOTO) study. Discussion: If association between proteolytic response to rt-PA and recanalization is confirmed, future clinical treatment may customize thrombolytic therapy to maximize outcomes and minimize adverse effects for individual patients

Thrombocytopenia in the experimental leptospirosis of guinea pig is not related to disseminated intravascular coagulation

BACKGROUND: Thrombocytopenia is commonly observed in severe leptospirosis. However, previous studies on coagulation alterations during leptospirosis resulted in inconsistent conclusions. Some findings showed that the prominent levels of thrombocytopenia observed in severe leptospirosis did not reflect the occurrence of disseminated intravascular coagulation (DIC) syndrome, while the others reached the conclusion that the hemorrhages observed in leptospirosis were due to DIC. The aim of this study is to elucidate whether DIC is an important feature of leptospirosis. METHODS: The leptospirosis model of guinea pig was established by intraperitoneal inoculation of Leptospira interrogans strain Lai. Hematoxylin and eosin (HE) staining, electron microscopy and immunohistochemistry staining were used to detect the pathologic changes. Platelet thrombus or fibrin thrombus was detected by HE, Martius Scarlet Blue (MSB) staining and electron microscopy. Hemostatic molecular markers such as 11-dehydrogenate thromboxane B2 (11-DH-TXB2), thrombomodulin (TM), thrombin-antithrombin III complex (TAT), D-Dimer and fibrin (ogen) degradation products (FDPs) in the plasma were examined by quantitative enzyme-linked immunosorbent assay (ELISA) to evaluate the hematological coagulative alterations in leptospirosis models. RESULTS: Pulmonary hemorrhage appeared in the model guinea pig 24 hours after leptospires intraperitoneal inoculation, progressing to a peak at 96 hours after the infection. Leptospires were detected 24 hours post-inoculation in the liver, 48 hours in the lung and 72 hours in the kidney by immunohistochemistry staining. Spiral form of the bacteria was initially observed in the liver, lung and kidney suggestive of intact leptospires, granular form of leptospires was seen as the severity increased. Platelet aggregation in hepatic sinusoid as well as phagocytosis of erythrocytes and platelets by Kupffer cells were both observed. Neither platelet thrombus nor fibrin thrombus was found in the liver, lung or kidney via morphological observation. Thrombocytopenia was observed in all infected guinea pigs of our experimental leptospirosis study. Analysis of hematologic molecular markers showed that 11-DH-TXB2 and TM in the plasma were elevated significantly. TAT that reflects the thrombin activation had a trend of decline after infection. Although D-dimer and FDPs increased statistically, the increasing may not bear clinical significance. CONCLUSION: Pathologic and hematological studies for experimental leptospirosis of guinea pig indicated that the thrombocytopenia found in guinea pigs did not correlate with the occurrence of DIC. The platelet aggregation and Kupffer cells phagocytosis might be the potential causes of thrombocytopenia in severe leptospirosis

Survey of oxaliplatin-associated neurotoxicity using an interview-based questionnaire in patients with metastatic colorectal cancer

BACKGROUND: New chemotherapy regimens for patients with colorectal cancer have improved survival, but at the cost of clinical toxicity. Oxaliplatin, an agent used in first-line therapy for metastatic colorectal cancer, causes acute and chronic neurotoxicity. This study was performed to carefully assess the incidence, type and duration of oxaliplatin neurotoxicity. METHODS: A detailed questionnaire was completed after each chemotherapy cycle for patients with metastatic colorectal cancer enrolled in a phase I trial of oxaliplatin and capecitabine. An oxaliplatin specific neurotoxicity scale was used to grade toxicity. RESULTS: Eighty-six adult patients with colorectal cancer were evaluated. Acute neuropathy symptoms included voice changes, visual alterations, pharyngo-laryngeal dysesthesia (lack of awareness of breathing); peri-oral or oral numbness, pain and symptoms due to muscle contraction (spasm, cramps, tremors). When the worst neurotoxicity per patient was considered, grade 1/2/3/4 dysesthesias and paresthesias were seen in 71/12/5/0 and 66/20/7/1 percent of patients. By cycles 3, 6, 9, and 12, oxaliplatin dose reduction or discontinuation was needed in 2.7%, 20%, 37.5% and 62.5% of patients. CONCLUSION: Oxaliplatin-associated acute neuropathy causes a variety of distressing, but transient, symptoms due to peripheral sensory and motor nerve hyperexcitability. Chronic neuropathy may be debilitating and often necessitates dose reductions or discontinuation of oxaliplatin. Patients should be warned of the possible spectrum of symptoms and re-assured about the transient nature of acute neurotoxicity. Ongoing studies are addressing the treatment and prophylaxis of oxaliplatin neurotoxicity

Associations of Early Systolic Blood Pressure Control and Outcome after Thrombolysis-Eligible Acute Ischemic Stroke: Results from the ENCHANTED Study

Background and Purpose: In thrombolysis-eligible patients with acute ischemic stroke, there is uncertainty over the most appropriate systolic blood pressure (SBP) lowering profile that provides an optimal balance of potential benefit (functional recovery) and harm (intracranial hemorrhage). We aimed to determine relationships of SBP parameters and outcomes in thrombolyzed acute ischemic stroke patients. Methods: Post hoc analyzes of the ENCHANTED (Enhanced Control of Hypertension and Thrombolysis Stroke Study), a partial-factorial trial of thrombolysis-eligible and treated acute ischemic stroke patients with high SBP (150-180 mm Hg) assigned to low-dose (0.6 mg/kg) or standard-dose (0.9 mg/kg) alteplase and intensive (target SBP, 130-140 mm Hg) or guideline-recommended (target SBP <180 mm Hg) treatment. All patients were followed up for functional status and serious adverse events to 90 days. Logistic regression models were used to analyze 3 SBP summary measures postrandomization: attained (mean), variability (SD) in 1-24 hours, and magnitude of reduction in 1 hour. The primary outcome was a favorable shift on the modified Rankin Scale. The key safety outcome was any intracranial hemorrhage. Results: Among 4511 included participants (mean age 67 years, 38% female, 65% Asian) lower attained SBP and smaller SBP variability were associated with favorable shift on the modified Rankin Scale (per 10 mm Hg increase: odds ratio, 0.76 [95% CI, 0.71-0.82]; P<0.001 and 0.86 [95% CI, 0.76-0.98]; P=0.025) respectively, but not for magnitude of SBP reduction (0.98, [0.93-1.04]; P=0.564). Odds of intracranial hemorrhage was associated with higher attained SBP and greater SBP variability (1.18 [1.06-1.31]; P=0.002 and 1.34 [1.11-1.62]; P=0.002) but not with magnitude of SBP reduction (1.05 [0.98-1.14]; P=0.184). Conclusions: Attaining early and consistent low levels in SBP <140 mm Hg, even as low as 110 to 120 mm Hg, over 24 hours is associated with better outcomes in thrombolyzed acute ischemic stroke patients. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01422616

Tuning the Mammalian Circadian Clock: Robust Synergy of Two Loops

The circadian clock is accountable for the regulation of internal rhythms in most living organisms. It allows the anticipation of environmental changes during the day and a better adaptation of physiological processes. In mammals the main clock is located in the suprachiasmatic nucleus (SCN) and synchronizes secondary clocks throughout the body. Its molecular constituents form an intracellular network which dictates circadian time and regulates clock-controlled genes. These clock-controlled genes are involved in crucial biological processes including metabolism and cell cycle regulation. Its malfunction can lead to disruption of biological rhythms and cause severe damage to the organism. The detailed mechanisms that govern the circadian system are not yet completely understood. Mathematical models can be of great help to exploit the mechanism of the circadian circuitry. We built a mathematical model for the core clock system using available data on phases and amplitudes of clock components obtained from an extensive literature search. This model was used to answer complex questions for example: how does the degradation rate of Per affect the period of the system and what is the role of the ROR/Bmal/REV-ERB (RBR) loop? Our findings indicate that an increase in the RNA degradation rate of the clock gene Period (Per) can contribute to increase or decrease of the period - a consequence of a non-monotonic effect of Per transcript stability on the circadian period identified by our model. Furthermore, we provide theoretical evidence for a potential role of the RBR loop as an independent oscillator. We carried out overexpression experiments on members of the RBR loop which lead to loss of oscillations consistent with our predictions. These findings challenge the role of the RBR loop as a merely auxiliary loop and might change our view of the clock molecular circuitry and of the function of the nuclear receptors (REV-ERB and ROR) as a putative driving force of molecular oscillations

Suicides among Danish cancer patients 1971–1999

Compared to the general population, the suicide risk among Danish cancer patients diagnosed in 1971–1986 was increased by 50% for men and 30% for women. We updated the earlier study to evaluate both long-term and recent trends in the suicide risk. Cancer patients with a first cancer diagnosed between 1971 and 1999 in Denmark were followed-up for completed suicide through 1999. Excluding nonmelanoma skin cancer, 564 508 cancer patients were included and 1241 suicides observed. Both the standardised mortality ratio (SMR) of suicide relative to the general population and the suicide rates were analysed with Poisson regression methods. The overall SMR was increased to 1.7 (95% CI. 1.6–1.9) for men and 1.4 (95% CI: 1.3–1.5) for women. Following the cancer diagnosis, the suicide risk was highest in the first 3 months for men and between months 3 and 12 for women. The risk was higher for nonlocalised cancer and for cancers with perceived poor prognosis. Breast cancer patients had a higher risk than other cancer patients with similar good prognosis. The suicide rates among cancer patients decreased with calendar time, but less so than the rates in the general population. The suicide risk among cancer patients has not decreased as much as in the Danish population and reasons for this should be explored. Breast cancer might be believed by patients to be more life threatening than it is. Assessment and treatment of depression could improve the quality of life for cancer patients who suffer from unrecognised depressions and in turn reduce the risk of suicide in cancer patients