Medical Research Council

About: Medical Research Council is a government organization based out in London, United Kingdom. It is known for research contribution in the topics: Population & Malaria. The organization has 16430 authors who have published 19150 publications receiving 1475494 citations.

Evolution of genes and genomes on the Drosophila phylogeny.

Abstract: Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.

The influence of immaturity on hypoxic-ischemic brain damage in the rat

Abstract: Brain damage in the Levine preparation (unilateral common carotid artery ligation with hypoxia) consists of ischemic neuronal alterations in the ipsilateral forebrain. As the model has been restricted to adult animals, unilateral common carotid artery ligation was carried out in 7-day-postnatal rats. Four to 8 hours later the 25 pups were exposed to 8% oxygen at 37 degrees C for 3.5 hours. Controls consisted of littermates subjected to carotid ligation without subsequent hypoxia, hypoxia without prior ligation, and neither ligation nor hypoxia. After hypoxia the animals were returned to their dams and appeared normal for up to 50 hours. All pups were then killed by perfusion-fixation. Moderate to severe ischemic neuronal changes were seen in the ipsilateral cerebral cortex, striatum, and hippocampus in at least 90% of the animals and included infarction in 56% of the brains. Cortical damage was occasionally laminar but more often occurred in columns at right angles to the pial surface. Unlike adult animals, there was necrosis of white matter, greater ipsilaterally, originating in and spreading from myelinogenic foci. The evolution of ischemic cell change and the associated gliomesodermal reaction was more rapid than in the adult. In 22 additional pups subjected to carotid artery ligation and hypoxia, brains were analyzed for water content. Significant increases (0.6 to 3.3%) in water content of the ipsilateral hemispheres occurred in 11 of 22 brains (50%). Unilateral ischemia combined with hypoxia in developing rats therefore results in neuronal destruction in the same brain regions as in adult animals, but also causes necrosis of white matter. The incidence of increased water content was similar to that of overt infarction. Thus, as previously shown in the adult, brain edema is a consequence rather than a cause of major ischemic damage in the immature animal.

CD4+ count-guided interruption of antiretroviral treatment.

Abstract: Methods We randomly assigned persons infected with HIV who had a CD4+ cell count of more than 350 per cubic millimeter to the continuous use of antiretroviral therapy (the viral suppression group) or the episodic use of antiretroviral therapy (the drug conservation group). Episodic use involved the deferral of therapy until the CD4+ count decreased to less than 250 per cubic millimeter and then the use of therapy until the CD4+ count increased to more than 350 per cubic millimeter. The primary end point was the development of an opportunistic disease or death from any cause. An important secondary end point was major cardiovascular, renal, or hepatic disease. Results A total of 5472 participants (2720 assigned to drug conservation and 2752 to viral suppression) were followed for an average of 16 months before the protocol was modified for the drug conservation group. At baseline, the median and nadir CD4+ counts were 597 per cubic millimeter and 250 per cubic millimeter, respectively, and 71.7% of participants had plasma HIV RNA levels of 400 copies or less per milliliter. Opportunistic disease or death from any cause occurred in 120 participants (3.3 events per 100 person-years) in the drug conservation group and 47 participants (1.3 per 100 person-years) in the viral suppression group (hazard ratio for the drug conservation group vs. the viral suppression group, 2.6; 95% confidence interval [CI], 1.9 to 3.7; P<0.001). Hazard ratios for death from any cause and for major cardiovascular, renal, and hepatic disease were 1.8 (95% CI, 1.2 to 2.9; P = 0.007) and 1.7 (95% CI, 1.1 to 2.5; P = 0.009), respectively. Adjustment for the latest CD4+ count and HIV RNA level (as time-updated covariates) reduced the hazard ratio for the primary end point from 2.6 to 1.5 (95% CI, 1.0 to 2.1). Conclusions Episodic antiretroviral therapy guided by the CD4+ count, as used in our study, significantly increased the risk of opportunistic disease or death from any cause, as compared with continuous antiretroviral therapy, largely as a consequence of lowering the CD4+ cell count and increasing the viral load. Episodic antiretroviral therapy does not reduce the risk of adverse events that have been associated with antiretroviral therapy. (ClinicalTrials.gov number, NCT00027352.)

The Toxicology of Mercury and Its Chemical Compounds

Abstract: This review covers the toxicology of mercury and its compounds. Special attention is paid to those forms of mercury of current public health concern. Human exposure to the vapor of metallic mercury dates back to antiquity but continues today in occupational settings and from dental amalgam. Health risks from methylmercury in edible tissues of fish have been the subject of several large epidemiological investigations and continue to be the subject of intense debate. Ethylmercury in the form of a preservative, thimerosal, added to certain vaccines, is the most recent form of mercury that has become a public health concern. The review leads to general discussion of evolutionary aspects of mercury, protective and toxic mechanisms, and ends on a note that mercury is still an "element of mystery."