611 research outputs found
In support of descriptive studies; relevance to translational research
The contemporary scientific establishment equates hypothesis testing to good science. This stance bypasses the preliminary need to identify a worthwhile hypothesis through rigorous observation of natural processes. If alleviation of human suffering is claimed as the goal of a scientific undertaking, it would be unfair to test a hypothesis whose relevance to human disease has not been satisfactorily proven. Here, we argue that descriptive investigations based on direct human observation should be highly valued and regarded essential for the selection of worthwhile hypotheses while the pursuit of costly scientific investigations without such evidence is a desecration of the cause upon which biomedical research is grounded
Vitamin D receptor ChIP-seq in primary CD4+ cells: relationship to serum 25-hydroxyvitamin D levels and autoimmune disease
PMCID: PMC3710212This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
Silica-Encapsulated Efficient and Stable Si Quantum Dots with High Biocompatibility
A facile fabrication method to produce biocompatible semiconductor Quantum Dots encapsulated in high quality and thick thermal oxide is presented. The process employs sonication of porous Si/SiO2 structures to produce flakes with dimension in the 50–200 nm range. These flakes show a coral-like SiO2 skeleton with Si nanocrystals embedded in and are suitable for functionalization with other diagnostic or therapeutic agents. Silicon is a biocompatible material, efficiently cleared from the human body. The Photoluminescence emission falls in the transparency window for living tissues and is found to be bright and stable for hours in the aggressive biological environment
What influences national and foreign physicians’ geographic distribution? An analysis of medical doctors’ residence location in Portugal
Background
The debate over physicians’ geographical distribution has attracted the attention of the
economic and public health literature over the last forty years. Nonetheless, it is still to date
unclear what influences physicians’ location, and whether foreign physicians contribute to fill
the geographical gaps left by national doctors in any given country. The present research sets
out to investigate the current distribution of national and international physicians in Portugal, with the objective to understand its determinants and provide an evidence base for policymakers to identify policies to influence it.
Methods
A cross-sectional study of physicians currently registered in Portugal was conducted to describe the population and explore the association of physician residence patterns with relevant personal and municipality characteristics. Data from the Portuguese Medical Council
on physicians’ residence and characteristics were analysed, as well as data from the National Institute of Statistics on municipalities’ population, living standards and health care network.
Descriptive statistics, chi-square tests, negative binomial and logistic regression modelling were applied to determine: (a) municipality characteristics predicting Portuguese and International physicians’ geographical distribution, and; (b) doctors’ characteristics that could
increase the odds of residing outside the country’s metropolitan areas.
Results
There were 39,473 physicians in Portugal in 2008, 51.1% of whom male, and 40.2% between
41 and 55 years of age. They were predominantly Portuguese (90.5%), with Spanish,
Brazilian and African nationalities also represented. Population, Population’s Purchasing
Power, Nurses per capita and Municipality Development Index (MDI) were the municipality
characteristics displaying the strongest association with national physicians’ location. For
foreign physicians, the MDI was not statistically significant, while municipalities’ foreign
population applying for residence appeared to be an additional positive factor in their location
decisions. In general, being foreigner and male resulted to be the physician characteristics
increasing the odds of residing outside the metropolitan areas. However, among the
internationals, older doctors were more likely to reside outside metropolitan areas. Being
Spanish or Brazilian (but not of African origin) was found to increase the odds of being based
outside the Lisbon and Oporto metropolitan areas.
Conclusions
The present study showed the relevance of studying one country’s physician population to
understand the factors driving national and international doctors’ location decisions. A more
nuanced understanding of national and foreign doctors’ location appears to be needed to
design more effective policies to reduce the imbalance of medical services across
geographical areas.The study was supported by a research grant from the Portuguese High Commission for Health to the International Health Department of the Institute of Hygiene and Tropical.
Medicine
Cellular Radiosensitivity: How much better do we understand it?
Purpose: Ionizing radiation exposure gives rise to a variety of lesions in DNA that result in genetic instability and potentially tumorigenesis or cell death. Radiation extends its effects on DNA by direct interaction or by radiolysis of H2O that generates free radicals or aqueous electrons capable of interacting with and causing indirect damage to DNA. While the various lesions arising in DNA after radiation exposure can contribute to the mutagenising effects of this agent, the potentially most damaging lesion is the DNA double strand break (DSB) that contributes to genome instability and/or cell death. Thus in many cases failure to recognise and/or repair this lesion determines the radiosensitivity status of the cell. DNA repair mechanisms including homologous recombination (HR) and non-homologous end-joining (NHEJ) have evolved to protect cells against DNA DSB. Mutations in proteins that constitute these repair pathways are characterised by radiosensitivity and genome instability. Defects in a number of these proteins also give rise to genetic disorders that feature not only genetic instability but also immunodeficiency, cancer predisposition, neurodegeneration and other pathologies.
Conclusions: In the past fifty years our understanding of the cellular response to radiation damage has advanced enormously with insight being gained from a wide range of approaches extending from more basic early studies to the sophisticated approaches used today. In this review we discuss our current understanding of the impact of radiation on the cell and the organism gained from the array of past and present studies and attempt to provide an explanation for what it is that determines the response to radiation
Micronuclei induced by reverse transcriptase inhibitors in mononucleated and binucleated cells as assessed by the cytokinesis-block micronucleus assay
This study evaluated the clastogenic and/or aneugenic potential of three nucleoside reverse transcriptase inhibitors (zidovudine - AZT, lamivudine - 3TC and stavudine - d4T) using the cytokinesis-block micronucleus (CBMN) assay in human lymphocyte cultures. All three inhibitors produced a positive response when tested in binucleated cells. The genotoxicity of AZT and 3TC was restricted to binucleated cells since there was no significant increase in the frequency of micronuclei in mononucleated cells. This finding indicated that AZT and 3TC caused chromosomal breakage and that their genotoxicity was related to a clastogenic action. In addition to the positive response observed with d4T in binucleated cells, this drug also increased the frequency of micronuclei in mononucleated cells, indicating clastogenic and aneugenic actions. Since the structural differences between AZT and 3TC and AZT and d4T involve the 3' position in the 2'-deoxyribonucleoside and in an unsaturated 2',3',dideoxyribose, respectively, we suggest that an unsaturated 2', 3', dideoxyribose is responsible for the clastogenic and aneugenic actions of d4T
Multidimensional associative factors for improvement in pain, function, and working capacity after rehabilitation of whiplash associated disorder: a prognostic, prospective outcome study
Observation of associated near-side and away-side long-range correlations in √sNN=5.02 TeV proton-lead collisions with the ATLAS detector
Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02 TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1 μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos2Δϕ modulation for all ΣETPb ranges and particle pT
Measurement of the production cross section for W-bosons in association with jets in pp collisions at s=7 TeV with the ATLAS detector
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