694 research outputs found
Quinoidization of regioregular oligo(THIENO[3,4-b]THIOPHENE)s
CaracterizaciĂłn de oligotiofenosUniversidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tec
Principle of Maximum Entropy Applied to Rayleigh-B\'enard Convection
A statistical-mechanical investigation is performed on Rayleigh-B\'enard
convection of a dilute classical gas starting from the Boltzmann equation. We
first present a microscopic derivation of basic hydrodynamic equations and an
expression of entropy appropriate for the convection. This includes an
alternative justification for the Oberbeck-Boussinesq approximation. We then
calculate entropy change through the convective transition choosing mechanical
quantities as independent variables. Above the critical Rayleigh number, the
system is found to evolve from the heat-conducting uniform state towards the
convective roll state with monotonic increase of entropy on the average. Thus,
the principle of maximum entropy proposed for nonequilibrium steady states in a
preceding paper is indeed obeyed in this prototype example. The principle also
provides a natural explanation for the enhancement of the Nusselt number in
convection.Comment: 13 pages, 4 figures; typos corrected; Eq. (66a) corrected to remove a
double counting for ; Figs. 1-4 replace
Validation of tissue microarrays for immunohistochemical profiling of cancer specimens using the example of human fibroblastic tumors
Family history of cancer, body weight, and p53 nuclear overexpression in Duke's C colorectal cancer.
To examine the hypothesis that colorectal carcinomas with and without TP53 mutations may be characterised by aetiological heterogeneity, we analysed a group of 107 patients with primary Dukes' C colorectal cancer seen at the Memorial Sloan-Kettering Cancer Center (MSKCC) from 1986 to 1990. We assessed p53 overexpression using the monoclonal antibody PAb 1801, and identified 42 (39%) patients displaying p53-positive phenotype, defined as > or = 25% of positive cells. Patients with two or more first-degree relatives with cancer had an odds ratio (OR) of 2.9 (95% CI 1.0-8.3) for p53 overexpression in comparison with those without a family history of cancer (trend test, P = 0.11). A possible association between body weight and p53 overexpression was observed. The ORs were 1.9 for the second quartile, 1.9 for the third quartile and 3.4 for the highest quartile in comparison with the lowest quartile (trend test, P = 0.06). No association between occupational physical activity, smoking, drinking, parity and p53 overexpression was identified. The results suggest that p53 overexpression may be related to genetic predisposition to colorectal cancer, and p53-positive and p53-negative colorectal cancers may be controlled by different aetiological pathways
Altered patterns of retinoblastoma gene product expression in adult soft-tissue sarcomas.
Altered expression of the retinoblastoma (RB) tumour-suppressor gene product (pRB) has been detected in sporadic bone and soft-tissue sarcomas. Earlier studies, analysing small cohorts of sarcoma patients, have suggested that these alterations are more commonly associated with high-grade tumours, metastatic lesions and poorer survival. This study was designed to re-examine the prevalence and clinical significance of altered pRB expression in a large and selected group of soft-tissue sarcomas from 174 adult patients. Representative tissue sections from these sarcomas were analysed by immunohistochemistry using a well-characterised anti-pRB monoclonal antibody. Tumours were considered to have a positive pRB phenotype only when pure nuclear staining was demonstrated, and cases were segregated into one of three groups. Group 1 (n = 36) were patients whose tumours have minimal or undetectable pRB nuclear staining (< 20% of tumour cells) and were considered pRB negative. Patients with tumours staining in a heterogeneous pattern (20-79% of tumour cells) were classified as group 2 (n = 99). The staining of group 3 (n = 39) was strongly positive with a homogeneous pRB nuclear immunoreactivity (80-100% of tumour cells). pRB alterations were frequently observed in both low- and high-grade lesions. Altered pRB expression did not correlate with known predictors of survival and was not itself an independent predictor of outcome in the long-term follow-up. These findings support earlier observations that alterations of pRB expression are common events in soft-tissue sarcomas; nevertheless, long-term follow-up results indicate that altered patterns of pRB expression do not influence clinical outcome of patients affected with soft-tissue sarcomas. It is postulated that RB alterations are primary events in human sarcomas and may be involved in tumorigenesis or early phases of tumour progression in these neoplasias
Challenges facing the elimination of sleeping sickness in west and central Africa: sustainable control of animal trypanosomiasis as an indispensable approach to achieve the goal
Reducing mortality and morbidity in patients with severe COVID-19 disease by advancing ongoing trials of Mesenchymal Stromal (stem) Cell (MSC) therapy - Achieving global consensus and visibility for cellular host-directed therapies
As of May 17th 2020, the novel coronavirus disease 2019 (COVID-19) pandemic has caused 307,395 deaths worldwide, out of 3,917,366 cases reported to the World Health Organization. No specific treatments for reducing mortality or morbidity are yet available. Deaths from COVID-19 will continue to rise globally until effective and appropriate treatments and/or vaccines are found. In search of effective treatments, the global medical, scientific, pharma and funding communities have rapidly initiated over 500 COVID-19 clinical trials on a range of antiviral drug regimens and repurposed drugs in various combinations. A paradigm shift is underway from the current focus of drug development targeting the pathogen, to advancing cellular Host-Directed Therapies (HDTs) for tackling the aberrant host immune and inflammatory responses which underlie the pathogenesis of SARS-CoV-2 and high COVID-19 mortality rates. We focus this editorial specifically on the background to, and the rationale for, the use and evaluation of mesenchymal stromal (Stem) cells (MSCs) in treatment trials of patients with severe COVID-19 disease. Currently, the ClinicalTrials.gov and the WHO Clinical Trials Registry Platform (WHO ICTRP) report a combined 28 trials exploring the potential of MSCs or their products for treatment of COVID-19. MSCs should also be trialed for treatment of other circulating WHO priority Blueprint pathogens such as MERS-CoV which causes upto 34% mortality rates. It's about time funding agencies invested more into development MSCs per se, and also for a range of other HDTs, in combination with other therapeutic interventions. MSC therapy could turn out to be an important contribution to bringing an end to the high COVID-19 death rates and preventing long-term functional disability in those who survive disease
Adipose tissue concentrations of non-persistent environmental phenols and local redox balance in adults from Southern Spain
The aim was to evaluate the associations of environmental phenol and paraben concentrations with the oxidative
microenvironment in adipose tissue. This study was conducted in a subsample (n=144) of the GraMo cohort
(Southern Spain). Concentrations of 9 phenols and 7 parabens, and levels of oxidative stress biomarkers were
quantified in adipose tissue. Associations were estimated using multivariable linear regression analyses adjusted
for potential confounders.
Benzophenone-3 (BP-3) concentration was borderline associated with enhanced glutathione peroxidase (GPx)
activity [exp(β)=1.20, p=0.060] and decreased levels of reduced glutathione (GSH) [exp(β)=0.55,
p=0.070]. Concentrations of bisphenol A (BPA) and methylparaben (MeP) were associated to lower glutathione
reductase (GRd) activity [exp(β)=0.83, exp(β)=0.72, respectively], and BPA was borderline associated
to increased levels of oxidized glutathione (GSSG) [exp(β)=1.73, p-value=0.062]. MeP was inversely
associated to both hemeoxygenase-1 (HO-1) and superoxide dismustase (SOD) activity, as well as to the levels of
thiobarbituric acid reactive substances (TBARS) [0.75 < exp(β) < 0.79].
Our results suggest that some specific non-persistent pollutants may be associated with a disruption of the
activity of relevant antioxidant enzymes, in addition to the depletion of the glutathione stock. They might act as
a tissue-specific source of free radicals, contributing to the oxidative microenvironment in the adipose tissue.This research was supported
in part by research grants from the European Union Commission
(H2020-EJP-HBM4EU and SOE1/P1/F0082), Biomedical Research
Networking Center-CIBER de EpidemiologĂa y Salud PĂşblica
(CIBERESP), from the Institute of Health Carlos III, supported by
European Regional Development Fund/FEDER (FIS-PI13/02406, FISPI14/
00067, FIS-PI16/01820, FIS-PI16/01812, FIS-PI16/01858 and
FIS-PI17/01743), and from the ConsejerĂa de Salud, Junta de AndalucĂa
(PS-0506-2016). Funding for the equipment used was provided by
Velux Fonden, Augustinus Fonden and Svend Andersen Fonden. The
authors thank Kirsten og Freddy Johansens Fond and the International
Centre for Research and Research Training in Endocrine Disruption of
Male Reproduction and Child Health (EDMaRC, Rigshospitalet,
Copenhagen University) for economic support. Dr. Juan Pedro Arrebola
is under contract within RamĂłn y Cajal Program (Ministerio de
EconomĂa, Industria y Competitividad de España, RYC-2016-20155)
Retinoblastoma protein expression is an independent predictor of both radiation response and survival in muscle-invasive bladder cancer
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