Imaging African trypanosomes

Trypanosoma brucei are extracellular kinetoplastid parasites transmitted by the blood-sucking tsetse fly. They are responsible for the fatal disease human African trypanosomiasis (HAT), also known as sleeping sickness. In late-stage infection, trypanosomes cross the blood–brain barrier (BBB) and invade the central nervous system (CNS) invariably leading to coma and death if untreated. There is no available vaccine and current late-stage HAT chemotherapy consists of either melarsoprol, which is highly toxic causing up to 8% of deaths, or nifurtimox–eflornithine combination therapy (NECT), which is costly and difficult to administer. There is therefore an urgent need to identify new late-stage HAT drug candidates. Here, we review how current imaging tools, ranging from fluorescent confocal microscopy of live immobilized cells in culture to whole-animal imaging, are providing insight into T. brucei biology, parasite-host interplay, trypanosome CNS invasion and disease progression. We also consider how imaging tools can be used for candidate drug screening purposes that could lead to new chemotherapies

Determining the Contribution of Epidermal Cell Shape to Petal Wettability Using Isogenic Antirrhinum Lines

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Sharing Data for Public Health Research by Members of an International Online Diabetes Social Network

Background: Surveillance and response to diabetes may be accelerated through engaging online diabetes social networks (SNs) in consented research. We tested the willingness of an online diabetes community to share data for public health research by providing members with a privacy-preserving social networking software application for rapid temporal-geographic surveillance of glycemic control. Methods and Findings: SN-mediated collection of cross-sectional, member-reported data from an international online diabetes SN entered into a software applicaction we made available in a “Facebook-like” environment to enable reporting, charting and optional sharing of recent hemoglobin A1c values through a geographic display. Self-enrollment by 17% (n = 1,136) of n = 6,500 active members representing 32 countries and 50 US states. Data were current with 83.1% of most recent A1c values reported obtained within the past 90 days. Sharing was high with 81.4% of users permitting data donation to the community display. 34.1% of users also displayed their A1cs on their SN profile page. Users selecting the most permissive sharing options had a lower average A1c (6.8%) than users not sharing with the community (7.1%, p = .038). 95% of users permitted re-contact. Unadjusted aggregate A1c reported by US users closely resembled aggregate 2007–2008 NHANES estimates (respectively, 6.9% and 6.9%, p = 0.85). Conclusions: Success within an early adopter community demonstrates that online SNs may comprise efficient platforms for bidirectional communication with and data acquisition from disease populations. Advancing this model for cohort and translational science and for use as a complementary surveillance approach will require understanding of inherent selection and publication (sharing) biases in the data and a technology model that supports autonomy, anonymity and privacy.Centers for Disease Control and Prevention (U.S.) (P01HK000088-01)Centers for Disease Control and Prevention (U.S.) (P01HK000016 )National Institute of Alcohol Abuse and Alcoholism (U.S.) (R21 AA016638-01A1)National Center for Research Resources (U.S.) (1U54RR025224-01)Children's Hospital (Boston, Mass.) (Program for Patient Safety and Quality

Evidence-based cardiovascular care in the community: A population-based cross-sectional study

BACKGROUND: Ischaemic heart disease and congestive heart failure are common and important conditions in family practice. Effective treatments may be underutilized, particularly in women and the elderly. The objective of the study was to determine the rate of prescribing of evidence-based cardiovascular medications and determine if these differed by patient age or sex. METHODS: We conducted a two-year cross-sectional study involving all hospitals in the province of Nova Scotia, Canada. Subjects were all patients admitted with ischaemic heart disease with or without congestive heart failure between 15 October 1997 and 14 October 1999. The main measure was the previous outpatient use of recommended medications. Chi-square analyses followed by multivariate logistic regression analyses were used to examine age-sex differences. RESULTS: Usage of recommended medications varied from approximately 60% for beta-blockers and angiotensin converting enzyme (ACE) inhibitors to 90% for antihypertensive agents. Patients aged 75 and over were significantly less likely than younger patients to be taking any of the medication classes. Following adjustment for age, there were no significant differences in medication use by sex except among women aged 75 and older who were more likely to be taking beta-blockers than men in the same age group. CONCLUSIONS: The use of evidence-based cardiovascular medications is rising and perhaps approaching reasonable levels for some drug classes. Family physicians should ensure that all eligible patients (prior myocardial infarction, congestive failure) are offered beta-blockers or ACE inhibitors

Home visits by family physicians during the end-of-life: Does patient income or residence play a role?

BACKGROUND: With a growing trend for those with advanced cancer to die at home, there is a corresponding increase in need for primary medical care in that setting. Yet those with lower incomes and in rural regions are often challenged to have their health care needs met. This study examined the association between patient income and residence and the receipt of Family Physician (FP) home visits during the end-of-life among patients with cancer. METHODS: Data Sources/Study Setting. Secondary analysis of linked population-based data. Information pertaining to all patients who died due to lung, colorectal, breast or prostate cancer between 1992 and 1997 (N = 7,212) in the Canadian province of Nova Scotia (NS) was extracted from three administrative health databases and from Statistics Canada census records. Study Design. An ecological measure of income ('neighbourhood' median household income) was developed using census information. Multivariate logistic regression was then used to assess the association of income with the receipt of at least one home visit from a FP among all subjects and by region of residency during the end-of-life. Covariates in the initial multivariate model included patient demographics and alternative health services information such as total days spent as a hospital inpatient. Data Extraction Methods. Encrypted patient health card numbers were used to link all administrative health databases whereas the postal code was the link to Statistics Canada census information. RESULTS: Over 45% of all subjects received at least one home visit (n = 3265). Compared to those from low income areas, the log odds of receiving at least one home visit was significantly greater among subjects who reside in middle to high income neighbourhoods (for the highest income quintile, adjusted odds ratio [OR] = 1.37, 95% confidence interval [CI] = 1.15, 1.64; for upper-middle income, adjusted OR = 1.19, 95%CI = 1.02, 1.39; for middle income, adjusted OR = 1.33, 95%CI = 1.15, 1.54). This association was found to be primarily associated with residency outside of the largest metropolitan region of the province. CONCLUSION: The likelihood of receiving a FP home visit during the end-of-life is associated with neighbourhood income particularly among patients living outside of a major metropolitan region

Assessing newborn body composition using principal components analysis: differences in the determinants of fat and skeletal size

BACKGROUND: Birth weight is a composite of skeletal size and soft tissue. These components are likely to have different growth patterns. The aim of this paper is to investigate the association between established determinants of birth weight and these separate components. METHODS: Weight, length, crown-rump, knee-heel, head circumference, arm circumference, and skinfold thicknesses were measured at birth in 699 healthy, term, UK babies recruited as part of the Exeter Family Study of Childhood Health. Corresponding measurements were taken on both parents. Principal components analysis with varimax rotation was used to reduce these measurements to two independent components each for mother, father and baby: one highly correlated with measures of fat, the other with skeletal size. RESULTS: Gestational age was significantly related to skeletal size, in both boys and girls (r = 0.41 and 0.52), but not fat. Skeletal size at birth was also associated with parental skeletal size (maternal: r = 0.24 (boys), r = 0.39 (girls) ; paternal: r = 0.16 (boys), r = 0.25 (girls)), and maternal smoking (0.4 SD reduction in boys, 0.6 SD reduction in girls). Fat was associated with parity (first borns smaller by 0.45 SD in boys; 0.31 SD in girls), maternal glucose (r = 0.18 (boys); r = 0.27 (girls)) and maternal fat (r = 0.16 (boys); r = 0.36 (girls)). CONCLUSION: Principal components analysis with varimax rotation provides a useful method for reducing birth weight to two more meaningful components: skeletal size and fat. These components have different associations with known determinants of birth weight, suggesting fat and skeletal size may have different regulatory mechanisms, which would be important to consider when studying the associations of birth weight with later adult disease

The 'Women's Lifestyle Study', 2-year randomized controlled trial of physical activity counselling in primary health care: rationale and study design

<p>Abstract</p> <p>Background</p> <p>Physical inactivity is an independent risk factor for diabetes and heart disease. There is evidence that increasing physical activity can reduce the risk of developing these chronic diseases, but less evidence about effective ways to increase adherence to physical activity. Interventions are therefore needed that produce sustained increases in adherence to physical activity, are cost-effective and improve clinical endpoints.</p> <p>Methods</p> <p>The Women's Lifestyle Study is a two year randomized controlled trial involving a nurse-led intervention to increase physical activity in 40–74 year old physically inactive women recruited from primary care. Baseline measures were assessed in a face-to-face interview with a primary care nurse. The intervention involved delivery of a 'Lifestyle script' by a primary care nurse followed by telephone counselling for nine months and a face-to-face nurse visit at six months. Outcome measurements are assessed at 12 and 24 months. The primary outcome is physical activity measured using a validated physical activity questionnaire. Secondary outcomes include blood pressure, weight, waist circumference, physical fitness (step test), serum HbA1c, fasting glucose, lipids, insulin, and quality of life (SF36). Costs were measured prospectively to allow a subsequent cost-effectiveness evaluation if the trial is positive.</p> <p>Discussion</p> <p>Due to report in 2008, the Women's Lifestyle Study tests the effectiveness of an enhanced low-cost, evidence-based intervention in increasing physical activity, and improving cardiovascular and diabetes risk indicators over two years. If successful in demonstrating improvements in health outcomes, this randomized controlled trial will be the first to demonstrate long-term cardiovascular and diabetes risk health benefit, in addition to improvements in physical activity, from a sustainable physical activity intervention based in primary care.</p> <p>Trial Registration</p> <p>Australian Clinical Trials Registry (ACTR), ACTRN012605000490673.</p

Falls Assessment Clinical Trial (FACT): design, interventions, recruitment strategies and participant characteristics

<p>Abstract</p> <p>Background</p> <p>Guidelines recommend multifactorial intervention programmes to prevent falls in older adults but there are few randomised controlled trials in a real life health care setting. We describe the rationale, intervention, study design, recruitment strategies and baseline characteristics of participants in a randomised controlled trial of a multifactorial falls prevention programme in primary health care.</p> <p>Methods</p> <p>Participants are patients from 19 primary care practices in Hutt Valley, New Zealand aged 75 years and over who have fallen in the past year and live independently. Two recruitment strategies were used – waiting room screening and practice mail-out. Intervention participants receive a community based nurse assessment of falls and fracture risk factors, home hazards, referral to appropriate community interventions, and strength and balance exercise programme. Control participants receive usual care and social visits. Outcome measures include number of falls and injuries over 12 months, balance, strength, falls efficacy, activities of daily living, quality of life, and physical activity levels.</p> <p>Results</p> <p>312 participants were recruited (69% women). Of those who had fallen, 58% of people screened in the practice waiting rooms and 40% when screened by practice letter were willing to participate. Characteristics of participants recruited using the two methods are similar (p > 0.05). Mean age of all participants was 81 years (SD 5). On average participants have 7 medical conditions, take 5.5 medications (29% on psychotropics) with a median of 2 falls (interquartile range 1, 3) in the previous year.</p> <p>Conclusion</p> <p>The two recruitment strategies and the community based intervention delivery were feasible and successful, identifying a high risk group with multiple falls. Recruitment in the waiting room gave higher response rates but was less efficient than practice mail-out. Testing the effectiveness of an evidence based intervention in a 'real life' setting is important.</p> <p>Trial registration</p> <p>Australian Clinical Trials Register ID 12605000054617.</p

Mining Predicted Essential Genes of Brugia malayi for Nematode Drug Targets

We report results from the first genome-wide application of a rational drug target selection methodology to a metazoan pathogen genome, the completed draft sequence of Brugia malayi, a parasitic nematode responsible for human lymphatic filariasis. More than 1.5 billion people worldwide are at risk of contracting lymphatic filariasis and onchocerciasis, a related filarial disease. Drug treatments for filariasis have not changed significantly in over 20 years, and with the risk of resistance rising, there is an urgent need for the development of new anti-filarial drug therapies. The recent publication of the draft genomic sequence for B. malayi enables a genome-wide search for new drug targets. However, there is no functional genomics data in B. malayi to guide the selection of potential drug targets. To circumvent this problem, we have utilized the free-living model nematode Caenorhabditis elegans as a surrogate for B. malayi. Sequence comparisons between the two genomes allow us to map C. elegans orthologs to B. malayi genes. Using these orthology mappings and by incorporating the extensive genomic and functional genomic data, including genome-wide RNAi screens, that already exist for C. elegans, we identify potentially essential genes in B. malayi. Further incorporation of human host genome sequence data and a custom algorithm for prioritization enables us to collect and rank nearly 600 drug target candidates. Previously identified potential drug targets cluster near the top of our prioritized list, lending credibility to our methodology. Over-represented Gene Ontology terms, predicted InterPro domains, and RNAi phenotypes of C. elegans orthologs associated with the potential target pool are identified. By virtue of the selection procedure, the potential B. malayi drug targets highlight components of key processes in nematode biology such as central metabolism, molting and regulation of gene expression

A Genetically Hard-Wired Metabolic Transcriptome in Plasmodium falciparum Fails to Mount Protective Responses to Lethal Antifolates

Genome sequences of Plasmodium falciparum allow for global analysis of drug responses to antimalarial agents. It was of interest to learn how DNA microarrays may be used to study drug action in malaria parasites. In one large, tightly controlled study involving 123 microarray hybridizations between cDNA from isogenic drug-sensitive and drug-resistant parasites, a lethal antifolate (WR99210) failed to over-produce RNA for the genetically proven principal target, dihydrofolate reductase-thymidylate synthase (DHFR-TS). This transcriptional rigidity carried over to metabolically related RNA encoding folate and pyrimidine biosynthesis, as well as to the rest of the parasite genome. No genes were reproducibly up-regulated by more than 2-fold until 24 h after initial drug exposure, even though clonal viability decreased by 50% within 6 h. We predicted and showed that while the parasites do not mount protective transcriptional responses to antifolates in real time, P. falciparum cells transfected with human DHFR gene, and adapted to long-term WR99210 exposure, adjusted the hard-wired transcriptome itself to thrive in the presence of the drug. A system-wide incapacity for changing RNA levels in response to specific metabolic perturbations may contribute to selective vulnerabilities of Plasmodium falciparum to lethal antimetabolites. In addition, such regulation affects how DNA microarrays are used to understand the mode of action of antimetabolites