1,940 research outputs found
αV β5 and CD44 are oxygen-regulated human embryonic stem cell attachment factors
Human embryonic stem cells (hESCs) have great potential for clinical therapeutic use. However, relatively little is known of the mechanisms which dictate their specificity of adhesion to substrates through adhesion proteins including integrins. Previous observations demonstrated enhanced clonogenicity in reduced oxygen culture systems. Here, we demonstrated via antibody blocking experiments that αV β5 and α 6 significantly promoted hESC attachment in 2% O2 only, whereas blockage of CD44 inhibited cell attachment in 21% O2 alone. Immunofluorescence confirmed expression of αV β5 and CD44 in both 2% O2 and 21% O2 cultured hESCs while flow cytometry revealed significantly higher αV β5 expression in 2% O2 versus 21% O2 cultured hESCs and higher CD44 expression in 21% O2 versus 2% O2 cultured hESCs. Adhered hESCs following blockage of αV β5 in 2% O2 displayed a reduction in nuclear colocalisation of Oct-4 and Nanog with little effect observed in 21% O2. Blockage of CD44 had the converse effect with dramatic reductions in nuclear colocalisation of Oct-4 and Nanog in 21% O2 cultured hESC which retained adherence, but not in 2% O2 cultured cells. Identification of oxygen-dependent substrate attachment mechanisms in hESCs has the potential to play a role in the development of novel substrates to improve hESC attachment and culture
Are ‘New’ Donors Different? Comparing the Allocation of Bilateral Aid between Non-DAC and DAC Donor Countries
ROX Index to Guide Management of COVID-19 Pneumonia
Coronavirus disease 2019 (COVID-19) caused by novel severe acute respiratory syndrome
coronavirus 2 (SARS-CoV-2) emerged from China in December 2019 leading to a global
pandemic (1). Approximately 17% of patients admitted to hospital require critical care, the
majority of whom undergo mechanical ventilation (MV) for pneumonia complicated by
hypoxaemia (2)
Legacy benefits of blood pressure treatment on cardiovascular events are primarily mediated by improved blood pressure variability: the ASCOT trial.
BACKGROUND AND AIMS: Visit-to-visit systolic blood pressure variability (BPV) is an important predictor of cardiovascular (CV) outcomes. The long-term effect of a period of blood pressure (BP) control, but with differential BPV, is uncertain. Morbidity and mortality follow-up of UK participants in the Anglo-Scandinavian Cardiac Outcomes Trial-Blood Pressure-Lowering Arm has been extended for up to 21 years to determine the CV impact of mean systolic blood pressure (SBP) control and BPV during the trial, and amongst those allocated to amlodipine- and atenolol-based treatment. METHODS: Eight thousand five hundred and eighty hypertensive participants (4305 assigned to amlodipine ± perindopril-based and 4275 to atenolol ± diuretic-based treatment during the in-trial period (median 5.5 years) were followed for up to 21 years (median 17.4 years), using linked hospital and mortality records. A subgroup of participants (n = 2156) was followed up 6 years after the trial closure with a self-administered questionnaire and a clinic visit. In-trial mean SBP and standard deviation of visit-to-visit SBP as a measure of BPV, were measured using >100 000 BP measurements. Cox proportional hazard models were used to estimate the risk [hazard ratios (HRs)], associated with (i) mean with SBP and BPV during the in-trial period, for the CV endpoints occurring after the end of the trial and (ii) randomly assigned treatment to events following randomization, for the first occurrence of pre-specified CV outcomes. RESULTS: Using BP data from the in-trial period, in the post-trial period, although mean SBP was a predictor of CV outcomes {HR per 10 mmHg, 1.14 [95% confidence interval (CI) 1.10-1.17], P < .001}, systolic BPV independent of mean SBP was a strong predictor of CV events [HR per 5 mmHg 1.22 (95% CI 1.18-1.26), P < .001] and predicted events even in participants with well-controlled BP. During 21-year follow-up, those on amlodipine-based compared with atenolol-based in-trial treatment had significantly reduced risk of stroke [HR 0.82 (95% CI 0.72-0.93), P = .003], total CV events [HR 0.93 (95% CI 0.88-0.98), P = .008], total coronary events [HR 0.92 (95% CI 0.86-0.99), P = .024], and atrial fibrillation [HR 0.91 (95% CI 0.83-0.99), P = .030], with weaker evidence of a difference in CV mortality [HR 0.91 (95% CI 0.82-1.01), P = .073]. There was no significant difference in the incidence of non-fatal myocardial infarction and fatal coronary heart disease, heart failure, and all-cause mortality. CONCLUSIONS: Systolic BPV is a strong predictor of CV outcome, even in those with controlled SBP. The long-term benefits of amlodipine-based treatment compared with atenolol-based treatment in reducing CV events appear to be primarily mediated by an effect on systolic BPV during the trial period
A Quantum Scattering Interferometer
The collision of two ultra-cold atoms results in a quantum-mechanical
superposition of two outcomes: each atom continues without scattering and each
atom scatters as a spherically outgoing wave with an s-wave phase shift. The
magnitude of the s-wave phase shift depends very sensitively on the interaction
between the atoms. Quantum scattering and the underlying phase shifts are
vitally important in many areas of contemporary atomic physics, including
Bose-Einstein condensates, degenerate Fermi gases, frequency shifts in atomic
clocks, and magnetically-tuned Feshbach resonances. Precise measurements of
quantum scattering phase shifts have not been possible until now because, in
scattering experiments, the number of scattered atoms depends on the s-wave
phase shifts as well as the atomic density, which cannot be measured precisely.
Here we demonstrate a fundamentally new type of scattering experiment that
interferometrically detects the quantum scattering phase shifts of individual
atoms. By performing an atomic clock measurement using only the scattered part
of each atom, we directly and precisely measure the difference of the s-wave
phase shifts for the two clock states in a density independent manner. Our
method will give the most direct and precise measurements of ultracold
atom-atom interactions and will place stringent limits on the time variations
of fundamental constants.Comment: Corrected formatting and typo
Linear Estimation of Location and Scale Parameters Using Partial Maxima
Consider an i.i.d. sample X^*_1,X^*_2,...,X^*_n from a location-scale family,
and assume that the only available observations consist of the partial maxima
(or minima)sequence, X^*_{1:1},X^*_{2:2},...,X^*_{n:n}, where
X^*_{j:j}=max{X^*_1,...,X^*_j}. This kind of truncation appears in several
circumstances, including best performances in athletics events. In the case of
partial maxima, the form of the BLUEs (best linear unbiased estimators) is
quite similar to the form of the well-known Lloyd's (1952, Least-squares
estimation of location and scale parameters using order statistics, Biometrika,
vol. 39, pp. 88-95) BLUEs, based on (the sufficient sample of) order
statistics, but, in contrast to the classical case, their consistency is no
longer obvious. The present paper is mainly concerned with the scale parameter,
showing that the variance of the partial maxima BLUE is at most of order
O(1/log n), for a wide class of distributions.Comment: This article is devoted to the memory of my six-years-old, little
daughter, Dionyssia, who leaved us on August 25, 2010, at Cephalonia isl. (26
pages, to appear in Metrika
Effect of mass dihydroartemisinin-piperaquine administration in southern Mozambique on the carriage of molecular markers of antimalarial resistance.
--- - Label: BACKGROUND NlmCategory: BACKGROUND content: Mass
drug administration (MDA) can rapidly reduce the burden of
Plasmodium falciparum (Pf). However, concerns remain about its
contribution to select for antimalarial drug resistance. -
Label: METHODS NlmCategory: METHODS content: We used Sanger
sequencing and real-time PCR to determine the proportion of
molecular markers associated with antimalarial resistance (k13,
pfpm2, pfmdr1 and pfcrt) in Pf isolates collected before (n =
99) and after (n = 112) the implementation of two monthly MDA
rounds with dihydroartemisinin-piperaquine (DHAp) for two
consecutive years in Magude district of Southern Mozambique. -
Label: RESULTS NlmCategory: RESULTS content: None of the k13
polymorphisms associated with artemisinin resistance were
observed in the Pf isolates analyzed. The proportion of Pf
isolates with multiple copies of pfpm2, an amplification
associated with piperaquine resistance, was similar in pre-
(4.9%) and post-MDA groups (3.4%; p = 1.000). No statistically
significant differences were observed between pre- and post-MDA
groups in the proportion of Pf isolates neither with mutations
in pfcrt and pfmdr1 genes, nor with the carriage of pfmdr1
multiple copies (p>0.05). - Label: CONCLUSIONS NlmCategory:
CONCLUSIONS content: This study does not show any evidence of
increased frequency of molecular makers of antimalarial
resistance after MDA with DHAp in southern Mozambique where
markers of antimalarial resistance were absent or low at the
beginning of the intervention
Costo-Efficacia di cabozantinib nel trattamento di seconda linea del tumore a cellule renali metastatico (mRCC) in Italia:
Introduction: Renal cell carcinoma (RCC) is the most common form of kidney cancer with >30% already metastatic at diagnosis. For patients who fail tyrosine kinase inhibitor (TKI) therapy, the Italian Medical Oncology Association recommends (level IA) nivolumab and cabozantinib. The aim of this study was to compare the cost-effectiveness of cabozantinib with nivolumab for treatment of adult patients with mRCC following prior TKI therapy in Italy. Methods: A partitioned survival (area under the curve) model was developed for the Italian medical environment. Cost-effectiveness was assessed from the Italian National Healthcare Service (SSN) perspective over a 30-year time horizon (annual discount: 3% rate). In the absence of head-to-head studies, clinical evidence was based on results of network meta-analysis. Health-state-related utilities were informed by EQ-5D data from the METEOR study. Resource use and costs were obtained from published sources. Results: Treatment with cabozantinib dominates nivolumab across a 30-years time horizon. In the reference case, treatment with cabozantinib results in an incremental 0.268 quality-adjusted life years (QALY) and an incremental 0.349 life years (LY) gained with a total saving, for the Italian SSN, of €5,605 compared to nivolumab over 30 years. Cabozantinib is associated with gains in quality adjusted life years versus nivolumab, in all analyses. Results were shown to be sensitive to drug prices variation and robust when altering other parameters. Discussion: Cabozantinib represents an efficient option in the management of mRCC after initial TKI-therapy in Italy. Drug prices impact final results, and this must be carefully considered, especially considering the confidential discounts and outcome/financial-based agreements currently in place in Italy
Outcomes of Multi-Drug Resistant Tuberculosis (MDR-TB) among a Cohort of South African Patients with High HIV Prevalence
Multidrug-resistant tuberculosis (MDR-TB) is a major clinical challenge, particularly in patients with human immunodeficiency virus (HIV) co-infection. MDR-TB treatment is increasingly available, but outcomes have not been well characterized. South Africa has provided MDR-TB treatment for a decade, and we evaluated outcomes by HIV status for patients enrolled between 2000 and 2004 prior to anti-retroviral access.We assessed treatment outcomes in a prospective cohort of patients with MDR-TB from eight provincial programs providing second line drugs. World Health Organization definitions were used. Results were stratified by HIV status.Seven hundred fifty seven patients with known HIV status were included in the final analysis, and HIV infection was documented in 287 (38%). Overall, 348 patients (46.0%) were successfully treated, 74 (9.8%) failed therapy, 177 (23.4%) died and 158 (20.9%) defaulted. Patients with HIV were slightly younger and less likely to be male compared to HIV negative patients. Patients with HIV were less likely to have a successful treatment outcome (40.0 vs. 49.6; P<0.05) and more likely to die (35.2 vs. 16.2; P<0.0001). In a competing risk survival analysis, patients with HIV had a higher hazard of death (HR: 2.33, P<0.0001). Low baseline weight (less than 45 kg and less than 60 kg) was also associated with a higher hazard of death (HR: 2.52, P<0.0001; and HR: 1.50, P<0.0001, respectively, compared to weight greater than 60 kg). Weight less than 45 kg had higher risk of failure (HR: 3.58, P<0.01). Any change in treatment regimen was associated with a higher hazard of default (HR: 2.86; 95% CI 1.55-5.29, P<0.001) and a lower hazard of death (HR: 0.63, P<0.05).In this MDR-TB treatment program patients with HIV infection and low weight had higher hazards of death. Overall treatment outcomes were poor. Efforts to improve treatment for MDR-TB are urgently needed
Enhancement of lipase activity in non-aqueous media upon immobilization on multi-walled carbon nanotubes
<p>Abstract</p> <p>Background</p> <p>Immobilization of biologically active proteins on nanosized surfaces is a key process in bionanofabrication. Carbon nanotubes with their high surface areas, as well as useful electronic, thermal and mechanical properties, constitute important building blocks in the fabrication of novel functional materials.</p> <p>Results</p> <p>Lipases from <it>Candida rugosa </it>(CRL) were found to be adsorbed on the multiwalled carbon nanotubes with very high retention of their biological activity (97%). The immobilized biocatalyst showed 2.2- and 14-fold increases in the initial rates of transesterification activity in nearly anhydrous hexane and water immiscible ionic liquid [Bmim] [PF6] respectively, as compared to the lyophilized powdered enzyme. It is presumed that the interaction with the hydrophobic surface of the nanotubes resulted in conformational changes leading to the 'open lid' structure of CRL. The immobilized enzyme was found to give 64% conversion over 24 h (as opposed to 14% with free enzyme) in the formation of butylbutyrate in nearly anhydrous hexane. Similarly, with ionic liquid [Bmim] [PF6], the immobilized enzyme allowed 71% conversion as compared to 16% with the free enzyme. The immobilized lipase also showed high enantioselectivity as determined by kinetic resolution of (±) 1-phenylethanol in [Bmim] [PF6]. While free CRL gave only 5% conversion after 36 h, the immobilized enzyme resulted in 37% conversion with > 99% enantiomeric excess. TEM studies on the immobilized biocatalyst showed that the enzyme is attached to the multiwalled nanotubes.</p> <p>Conclusion</p> <p>Successful immobilization of enzymes on nanosized carriers could pave the way for reduced reactor volumes required for biotransformations, as well as having a use in the construction of miniaturized biosensensor devices.</p
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