8,230 research outputs found
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High fludarabine exposure and relationship with treatment-related mortality after nonmyeloablative hematopoietic cell transplantation.
Despite its common use in nonmyeloablative preparative regimens, the pharmacokinetics of fludarabine are poorly characterized in hematopoietic cell transplantation (HCT) recipients and exposure-response relationships remain undefined. The objective of this study was to evaluate the association between plasma F-ara-A exposure, the systemically circulating moiety of fludarabine, and engraftment, acute GVHD, TRM and OS after HCT. The preparative regimen consisted of CY 50 mg/kg/day i.v. day -6; plus fludarabine 30-40 mg/m²/day i.v. on days -6 to -2 and TBI 200 cGy on day -1. F-ara-A pharmacokinetics were carried out with the first dose of fludarabine in 87 adult patients. Median (range) F-ara-A area-under-the-curve (AUC((0-∞))) was 5.0 μg h/mL (2.0-11.0), clearance 15.3 L/h (6.2-36.6), C(min) 55 ng/mL (17-166) and concentration on day(zero) 16.0 ng/mL (0.1-144.1). Despite dose reductions, patients with renal insufficiency had higher F-ara-A exposures. There was strong association between high plasma concentrations of F-ara-A and increased risk of TRM and reduced OS. Patients with an AUC((0-∞)) greater than 6.5 μg h/mL had 4.56 greater risk of TRM and significantly lower OS. These data suggest that clinical strategies are needed to optimize dosing of fludarabine to prevent overexposure and toxicity in HCT
In an in vitro model of human tuberculosis, monocyte-microglial networks regulate matrix metalloproteinase-1 and -3 gene expression and secretion via a p38 mitogen activated protein kinase-dependent pathway.
BACKGROUND: Tuberculosis (TB) of the central nervous system (CNS) is characterized by extensive tissue inflammation, driven by molecules that cleave extracellular matrix such as matrix metalloproteinase (MMP)-1 and MMP-3. However, relatively little is known about the regulation of these MMPs in the CNS. METHODS: Using a cellular model of CNS TB, we stimulated a human microglial cell line (CHME3) with conditioned medium from Mycobacterium tuberculosis-infected primary human monocytes (CoMTb). MMP-1 and MMP-3 secretion was detected using ELISAs confirmed with casein zymography or western blotting. Key results of a phospho-array profile that detects a wide range of kinase activity were confirmed with phospho-Western blotting. Chemical inhibition (SB203580) of microglial cells allowed investigation of expression and secretion of MMP-1 and MMP-3. Finally we used promoter reporter assays employing full length and MMP-3 promoter deletion constructs. Student's t-test was used for comparison of continuous variables and multiple intervention experiments were compared by one-way ANOVA with Tukey's correction for multiple pairwise comparisons. RESULTS: CoMTb up-regulated microglial MMP-1 and MMP-3 secretion in a dose- and time-dependent manner. The phospho-array profiling showed that the major increase in kinase activity due to CoMTb stimulation was in p38 mitogen activated protein kinase (MAPK), principally the α and γ subunits. p38 phosphorylation was detected at 15 minutes, with a second peak of activity at 120 minutes. High basal extracellular signal-regulated kinase activity was further increased by CoMTb. Secretion and expression of MMP-1 and MMP-3 were both p38 dependent. CoMTb stimulation of full length and MMP-3 promoter deletion constructs demonstrated up-regulation of activity in the wild type but a suppression site between -2183 and -1612 bp. CONCLUSIONS: Monocyte-microglial network-dependent MMP-1 and MMP-3 gene expression and secretion are dependent upon p38 MAPK in tuberculosis. p38 is therefore a potential target for adjuvant therapy in CNS TB
The structure and micromechanics of elastic tissue.
Journal ArticleReviewElastin is a major component of tissues such as lung and blood vessels, and endows them with the long-range elasticity necessary for their physiological functions. Recent research has revealed the complexity of these elastin structures and drawn attention to the existence of extensive networks of fine elastin fibres in tissues such as articular cartilage and the intervertebral disc. Nonlinear microscopy, allowing the visualization of these structures in living tissues, is informing analysis of their mechanical properties. Elastic fibres are complex in composition and structure containing, in addition to elastin, an array of microfibrillar proteins, principally fibrillin. Raman microspectrometry and X-ray scattering have provided new insights into the mechanisms of elasticity of the individual component proteins at the molecular and fibrillar levels, but more remains to be done in understanding their mechanical interactions in composite matrices. Elastic tissue is one of the most stable components of the extracellular matrix, but impaired mechanical function is associated with ageing and diseases such as atherosclerosis and diabetes. Efforts to understand these associations through studying the effects of processes such as calcium and lipid binding and glycation on the mechanical properties of elastin preparations in vitro have produced a confusing picture, and further efforts are required to determine the molecular basis of such effects.British Heart FoundationArthritis U
Rapid generation of chromosome-specific alphoid DNA probes using the polymerase chain reaction
Non-isotopic in situ hybridization of chromosome-specific alphoid DNA probes has become a potent tool in the study of numerical aberrations of specific human chromosomes at all stages of the cell cycle. In this paper, we describe approaches for the rapid generation of such probes using the polymerase chain reaction (PCR), and demonstrate their chromosome specificity by fluorescence in situ hybridization to normal human metaphase spreads and interphase nuclei. Oligonucleotide primers for conserved regions of the alpha satellite monomer were used to generate chromosome-specific DNA probes from somatic hybrid cells containing various human chromosomes, and from DNA libraries from sorted human chromosomes. Oligonucleotide primers for chromosome-specific regions of the alpha satellite monomer were used to generate specific DNA probes for the pericentromeric heterochromatin of human chromosomes 1, 6, 7, 17 and X directly from human genomic DNA
How does reviewing the evidence change veterinary surgeons' beliefs regarding the treatment of ovine footrot? A quantitative and qualitative study
Footrot is a widespread, infectious cause of lameness in sheep, with major economic and welfare costs. The aims of this research were: (i) to quantify how veterinary surgeons’ beliefs regarding the efficacy of two treatments for footrot changed following a review of the evidence (ii) to obtain a consensus opinion following group discussions (iii) to capture complementary qualitative data to place their beliefs within a broader clinical context. Grounded in a Bayesian statistical framework, probabilistic elicitation (roulette method) was used to quantify the beliefs of eleven veterinary surgeons during two one-day workshops. There was considerable heterogeneity in veterinary surgeons’ beliefs before they listened to a review of the evidence. After hearing the evidence, seven participants quantifiably changed their beliefs. In particular, two participants who initially believed that foot trimming with topical oxytetracycline was the better treatment, changed to entirely favour systemic and topical oxytetracycline instead. The results suggest that a substantial amount of the variation in beliefs related to differences in veterinary surgeons’ knowledge of the evidence. Although considerable differences in opinion still remained after the evidence review, with several participants having non-overlapping 95% credible intervals, both groups did achieve a consensus opinion. Two key findings from the qualitative data were: (i) veterinary surgeons believed that farmers are unlikely to actively seek advice on lameness, suggesting a proactive veterinary approach is required (ii) more attention could be given to improving the way in which veterinary advice is delivered to farmers. In summary this study has: (i) demonstrated a practical method for probabilistically quantifying how veterinary surgeons’ beliefs change (ii) revealed that the evidence that currently exists is capable of changing veterinary opinion (iii) suggested that improved transfer of research knowledge into veterinary practice is needed (iv) identified some potential obstacles to the implementation of veterinary advice by farmers
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JAK2V617F mediates resistance to DNA damage-induced apoptosis by modulating FOXO3A localization and Bcl-xL deamidation.
The JAK2V617F mutation is found in most patients with a myeloproliferative neoplasm (MPN). This gain-of-function mutation dysregulates cytokine signaling and is associated with increased accumulation of DNA damage, a process likely to drive disease evolution. JAK2V617F inhibits NHE-1 upregulation in response to DNA damage and consequently represses Bcl-xL deamidation and apoptosis, thus giving rise to inappropriate cell survival. However, the mechanism whereby NHE-1 expression is inhibited by JAK2V617F is unknown. In this study, we demonstrate that the accumulation of reactive oxygen species (ROS) in cells expressing JAK2V617F compromises the NHE-1/Bcl-xL deamidation pathway by repressing NHE-1 upregulation in response to DNA damage. In JAK2V617F-positive cells, increased ROS levels results from aberrant PI3K signaling, which decreases nuclear localization of FOXO3A and decreases catalase expression. Furthermore, when compared with autologous control erythroblasts, clonally derived JAK2V617F-positive erythroblasts from MPN patients displayed increased ROS levels and reduced nuclear FOXO3A. However, in hematopoietic stem cells (HSCs), FOXO3A is largely localized within the nuclei despite the presence of JAK2V617F mutation, suggesting that JAK2-FOXO signaling has a different effect on progenitors compared with stem cells. Inactivation of FOXO proteins and elevation of intracellular ROS are characteristics common to many cancers, and hence these findings are likely to be of relevance beyond the MPN field.Work in the Green lab is supported by Leukemia and Lymphoma
Research, Cancer Research UK, the Kay Kendall Leukaemia Fund, the NIHR
Cambridge Biomedical Research Centre, the Cambridge Experimental Cancer
Medicine Centre, and the Leukemia & Lymphoma Society of America. DGK was
supported by a postdoctoral fellowship from the Canadian Institutes of Health
Research (Ottawa, ON), and a Lady Tata Memorial Trust International Award for
Research in Leukaemia (London, UK). HJP was supported by a postdoctoral
fellowship from the Human Frontier Science Program.This is the accepted manuscript. The final version is available at http://www.nature.com/onc/journal/vaop/ncurrent/full/onc2015285a.html
OKT3 and viral disease in pediatric liver transplant recipients
Seventy-four consecutive pediatric liver transplant recipients were reviewed to assess the effect of the monoclonal anti-T-lymphocyte antibody OKT3 on subsequent viral infection (9 patients were excluded due to postoperative demise during the 1st week). Twenty-two patients received OKT3 in addition to standard cyclosporine-prednisone immunosuppression for either steroid-resistant acute rejection (18) or to facilitate reduction of cyclosporine due to severe renal impairment (4). Invasive infections were diagnosed by histology or culture in tissue biopsies or bronchoalveolar lavage specimens. The overall incidence of viral infection was 58%, half of which was due to cytomegalovirus (CMV). Invasive viral disease was associated with increased mortality (37% vs. 3% p = 0.001). Viral-related deaths were due to CMV (5), disseminated adenovirus (3), disseminated enterovirus (1) and respiratory syncytial viral pneumonia (1). The use of OKT3 was associated with increased viral disease (59% vs. 33% p = 0.04) and invasive primary CMV disease (58% vs. 19% p = 0.04). Trends were observed toward increased overall viral infection (73% vs. 51% p = 0.08), primary CMV infection (58% vs. 25% p = 0.08) and overall mortality (27% vs. 9% p = 0.08) following OKT3 therapy. We conclude that pediatric liver transplant recipients who require OKT3 therapy may be at increased risk for invasive viral disease and especially invasive primary CMV disease
Bridging the Mid-Infrared-to-Telecom Gap with Silicon Nanophotonic Spectral Translation
Expanding far beyond traditional applications in optical interconnects at
telecommunications wavelengths, the silicon nanophotonic integrated circuit
platform has recently proven its merits for working with mid-infrared (mid-IR)
optical signals in the 2-8 {\mu}m range. Mid-IR integrated optical systems are
capable of addressing applications including industrial process and
environmental monitoring, threat detection, medical diagnostics, and free-space
communication. Rapid progress has led to the demonstration of various silicon
components designed for the on-chip processing of mid-IR signals, including
waveguides, vertical grating couplers, microcavities, and electrooptic
modulators. Even so, a notable obstacle to the continued advancement of
chip-scale systems is imposed by the narrow-bandgap semiconductors, such as
InSb and HgCdTe, traditionally used to convert mid-IR photons to electrical
currents. The cryogenic or multi-stage thermo-electric cooling required to
suppress dark current noise, exponentially dependent upon the ratio Eg/kT, can
limit the development of small, low-power, and low-cost integrated optical
systems for the mid-IR. However, if the mid-IR optical signal could be
spectrally translated to shorter wavelengths, for example within the
near-infrared telecom band, photodetectors using wider bandgap semiconductors
such as InGaAs or Ge could be used to eliminate prohibitive cooling
requirements. Moreover, telecom band detectors typically perform with higher
detectivity and faster response times when compared with their mid-IR
counterparts. Here we address these challenges with a silicon-integrated
approach to spectral translation, by employing efficient four-wave mixing (FWM)
and large optical parametric gain in silicon nanophotonic wires
A semi-parametric approach to estimate risk functions associated with multi-dimensional exposure profiles: application to smoking and lung cancer
A common characteristic of environmental epidemiology is the multi-dimensional aspect of exposure patterns, frequently reduced to a cumulative exposure for simplicity of analysis. By adopting a flexible Bayesian clustering approach, we explore the risk function linking exposure history to disease. This approach is applied here to study the relationship between different smoking characteristics and lung cancer in the framework of a population based case control study
Mammography screening: views from women and primary care physicians in Crete
Background: Breast cancer is the most commonly diagnosed cancer among women and a leading cause of death from cancer in women in Europe. Although breast cancer incidence is on the rise worldwide, breast cancer mortality over the past 25 years has been stable or decreasing in some countries and a fall in breast cancer mortality rates in most European countries in the 1990s was reported by several studies, in contrast, in Greece have not reported these favourable trends. In Greece, the age-standardised incidence and mortality rate for breast cancer per 100.000 in 2006 was 81,8 and 21,7 and although it is lower than most other countries in Europe, the fall in breast cancer mortality that observed has not been as great as in other European countries. There is no national strategy for screening in this country. This study reports on the use of mammography among middleaged women in rural Crete and investigates barriers to mammography screening encountered by women and their primary care physicians.
Methods: Design: Semi-structured individual interviews. Setting and participants: Thirty women between 45–65
years of age, with a mean age of 54,6 years, and standard deviation 6,8 from rural areas of Crete and 28 qualified
primary care physicians, with a mean age of 44,7 years and standard deviation 7,0 serving this rural population.
Main outcome measure: Qualitative thematic analysis.
Results: Most women identified several reasons for not using mammography. These included poor knowledge
of the benefits and indications for mammography screening, fear of pain during the procedure, fear of a serious
diagnosis, embarrassment, stress while anticipating the results, cost and lack of physician recommendation.
Physicians identified difficulties in scheduling an appointment as one reason women did not use mammography
and both women and physicians identified distance from the screening site, transportation problems and the
absence of symptoms as reasons for non-use.
Conclusion: Women are inhibited from participating in mammography screening in rural Crete. The provision
of more accessible screening services may improve this. However physician recommendation is important in
overcoming women's inhibitions. Primary care physicians serving rural areas need to be aware of barriers
preventing women from attending mammography screening and provide women with information and advice in a sensitive way so women can make informed decisions regarding breast caner screening
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