Roles of the Bloom's syndrome helicase in the maintenance of genome stability

The RecQ family of DNA helicases is highly conserved in evolution from bacteria to humans. Of the five known human RecQ family members, three (BLM, WRN and RECQ4, which cause Bloom's syndrome, Werner's syndrome and Rothmund-Thomson syndrome respectively) are mutated in distinct clinical disorders associated with cancer predisposition and/or premature aging. BLM forms part of a multienzyme complex including topoisomerase IIIalpha, replication protein A and a newly identified factor called BLAP75. Together, these proteins play a role in the resolution of DNA structures that arise during the process of homologous recombination repair. In the absence of BLM, cells show genomic instability and a high incidence of sister-chromatid exchanges. In addition to a DNA structure-specific helicase activity, BLM also catalyses Holliday-junction branch migration and the annealing of complementary single-stranded DNA molecules

Form and focus: evaluation of CHAPS national interventions, 2003 to 2006

No abstract available

Prevalence, Determinants, and Clinical Significance of Masked Hypertension in a Population-Based Sample of African Americans: The Jackson Heart Study

Background: The disproportionate rates of cardiovascular disease in African Americans may, in part, be due to suboptimal assessment of blood pressure (BP) with clinic BP measurements alone. To date, however, the prevalence of masked hypertension in African Americans has not been fully delineated. The purpose of this study was to evaluate masked hypertension prevalence in a large population-based sample of African Americans and examine its determinants and association with indices of target organ damage (TOD). Methods: Clinic and 24-hour ambulatory BP monitoring were conducted in 972 African Americans enrolled in the Jackson Heart Study. Common carotid artery intima-media thickness, left ventricular mass index, and the urinary albumin:creatinine excretion ratio were evaluated as indices of TOD. Results: Masked hypertension prevalence was 25.9% in the overall sample and 34.4% in participants with normal clinic BP. All indices of TOD were significantly higher in masked hypertensives compared to sustained normotensives and were similar between masked hypertensives and sustained hypertensives. Male gender, smoking, diabetes, and antihypertensive medication use were independent determinants of masked hypertension in multivariate analyses. Conclusions: In this population-based cohort of African Americans, approximately one-third of participants with presumably normal clinic BP had masked hypertension when BP was assessed in their daily environment. Masked hypertension was accompanied by a greater degree of TOD in this cohort

Review of important reactions for the nitrogen chemistry in the interstellar medium

Predictions of astrochemical models depend strongly on the reaction rate coefficients used in the simulations. We reviewed a number of key reactions for the chemistry of nitrogen-bearing species in the dense interstellar medium and proposed new reaction rate coefficients for those reactions. The details of the reviews are given in the form of a datasheet associated with each reaction. The new recommended rate coefficients are given with an uncertainty and a temperature range of validity and will be included in KIDA (http://kida.obs.u-bordeaux1.fr).Comment: 39 pages, not published in refereed journal, datasheets are given in KID

Capital assets: a community research intervention by the African Forum in Redbridge and Watham Forest

Duration: September 1999 - November 2000 This was a community-led initiative in which over 1000 Africans resident in Redbridge and Waltham Forest were asked about their assets and health needs. The survey was instigated by Redbridge & Waltham Forest African Forum, and undertaken by community groups themselves in collaboration with Sigma Research. The survey was designed both to gather information from the communities and to provide information to them. The information sought was not simply about the participants needs but also about the assets within those communities to address those needs. The project sought information about the relationship between Africans living in Redbridge or Waltham Forest, their assets, health needs and the potential for interventions. It did so by: providing all stakeholders with clear and accessible information about the demography of the local African communities. mapping the priorities and needs of the groups. assessing knowledge about HIV and its prevention. mapping linguistic assets and social structures of participating community groups that may contribute to meeting these needs. identifying acceptable, culturally appropriate methods of intervention. Questionnaire content was led by the members of the African Forum as was the structure and content of the report. Members of community groups did all the interviewing. Between them, 41 interviewers talked to 1008 residents. The majority of African women and men living locally were at an age when people can be at their most active physically, mentally and economically. Mental health and HIV and AIDS were the major health concerns although health concerns were associated with country of birth. Many respondents lacked basic knowledge of HIV transmission. There is a need for more awareness of clinical sexual health services. Language ability and social networks are common assets for health. English is spoken by 78% of participants and 88% of the entire sample mentioned at least one person they were close to. The survey provides information that helps to identify key areas where community organisations and statutory services working in partnership can improve quality of life and access to services. The final report was called Capital assets: a community research intervention by The African Forum in Redbridge and Waltham Forest

Louse (Insecta : Phthiraptera) mitochondrial 12S rRNA secondary structure is highly variable

Lice are ectoparasitic insects hosted by birds and mammals. Mitochondrial 12S rRNA sequences obtained from lice show considerable length variation and are very difficult to align. We show that the louse 12S rRNA domain III secondary structure displays considerable variation compared to other insects, in both the shape and number of stems and loops. Phylogenetic trees constructed from tree edit distances between louse 12S rRNA structures do not closely resemble trees constructed from sequence data, suggesting that at least some of this structural variation has arisen independently in different louse lineages. Taken together with previous work on mitochondrial gene order and elevated rates of substitution in louse mitochondrial sequences, the structural variation in louse 12S rRNA confirms the highly distinctive nature of molecular evolution in these insects

BLM and RMI1 alleviate RPA inhibition of topoIIIα decatenase activity

RPA is a single-stranded DNA binding protein that physically associates with the BLM complex. RPA stimulates BLM helicase activity as well as the double Holliday junction dissolution activity of the BLM-topoisomerase IIIα complex. We investigated the effect of RPA on the ssDNA decatenase activity of topoisomerase IIIα. We found that RPA and other ssDNA binding proteins inhibit decatenation by topoisomerase IIIα. Complex formation between BLM, TopoIIIα, and RMI1 ablates inhibition of decatenation by ssDNA binding proteins. Together, these data indicate that inhibition by RPA does not involve species-specific interactions between RPA and BLM-TopoIIIα-RMI1, which contrasts with RPA modulation of double Holliday junction dissolution. We propose that topoisomerase IIIα and RPA compete to bind to single-stranded regions of catenanes. Interactions with BLM and RMI1 enhance toposiomerase IIIα activity, promoting decatenation in the presence of RPA