422 research outputs found
High-Resolution Microendoscopy for the Detection of Cervical Neoplasia in Low-Resource Settings
Cervical cancer is the second leading cause of cancer death among women in developing countries. Developing countries often lack infrastructure, cytotechnologists, and pathologists necessary to implement current screening tools. Due to their low cost and ease of interpretation at the point-of-care, optical imaging technologies may serve as an appropriate solution for cervical cancer screening in low resource settings. We have developed a high-resolution optical imaging system, the High Resolution Microendoscope (HRME), which can be used to interrogate clinically suspicious areas with subcellular spatial resolution, revealing changes in nuclear to cytoplasmic area ratio. In this pilot study carried out at the women's clinic of Princess Marina Hospital in Botswana, 52 unique sites were imaged in 26 patients, and the results were compared to histopathology as a reference standard. Quantitative high resolution imaging achieved a sensitivity and specificity of 86% and 87%, respectively, in differentiating neoplastic (≥CIN 2) tissue from non-neoplastic tissue. These results suggest the potential promise of HRME to assist in the detection of cervical neoplasia in low-resource settings
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Implementation of an Ultraviolet Phototherapy Service at a National Referral Hospital in Western Kenya: Reflections on Challenges and Lessons Learned.
IntroductionIn order to manage skin conditions at a national referral hospital level in Kenya, specialized dermatology services, such as dermatologic surgery, dermatopathology, phototherapy, and sub-specialty care, should be offered, as is typically available in referral hospitals around the world. A Kenyan patient with prurigo nodularis, whose severe itch remitted after phototherapy treatment at the University of California, San Francisco (UCSF), inspired the development of a phototherapy service at Academic Model Providing Access to Healthcare (AMPATH), a partnership in Western Kenya between Moi Teaching and Referral Hospital, Moi University College of Health Sciences, and a consortium of North American academic medical centers.MethodsInitial project funds were raised through a crowdfunding campaign and fundraising events. A new narrowband ultraviolet B phototherapy unit and replacement bulbs were donated and air shipped to Eldoret, Kenya. A team of dermatologists and phototherapy nurses from UCSF conducted a 2-day training session. US-based dermatologists affiliated with AMPATH provide ongoing support through regular communication and on-site visits.ResultsEarly in implementation, challenges faced included training clinical staff with limited experience in phototherapy and improving communication between nurses and clinicians. More recent challenges include frequent rotation of specialty clinic nurses in the dermatology clinic, adaptation of phototherapy guidelines to balance patient volume with service delivery capacity, and training assessment of disease activity in darkly pigmented skin.ConclusionStrategies that have been helpful in addressing implementation challenges include: increasing on-site and remote training opportunities for clinicians and nurses, developing a tiered payment schema, educating patients to combat misconceptions about phototherapy, dynamic phototherapy referral guidelines to accommodate service delivery capacity, and prioritizing the engagement of a multidisciplinary team
Child dietary patterns in Homo sapiens evolution: A systematic review
Dietary patterns spanning millennia could inform contemporary public health nutrition. Children are largely absent from evidence describing diets throughout human evolution, despite prevalent malnutrition today signaling a potential genome-environment divergence. This systematic review aimed to identify dietary patterns of children ages 6 months to 10 years consumed before the widespread adoption of agriculture. Metrics of mention frequency (counts of food types reported) and food groups (globally standardized categories) were applied to: compare diets across subsistence modes [gatherer-hunter-fisher (GHF), early agriculture (EA) groups]; examine diet quality and diversity; and characterize differences by life course phase and environmental context defined using Köppen-Geiger climate zones. The review yielded child diet information from 95 cultural groups (52 from GHF; 43 from EA/mixed subsistence groups). Animal foods (terrestrial and aquatic) were the most frequently mentioned food groups in dietary patterns across subsistence modes, though at higher frequencies in GHF than in EA. A broad range of fruits, vegetables, roots and tubers were more common in GHF, while children from EA groups consumed more cereals than GHF, associated with poor health consequences as reported in some studies. Forty-eight studies compared diets across life course phases: 28 showed differences and 20 demonstrated similarities in child versus adult diets. Climate zone was a driver of food patterns provisioned from local ecosystems. Evidence fro
Use of injectable hormonal contraception and women’s risk of herpes simplex virus type 2 acquisition: a prospective study of couples in Rakai, Uganda
Background The injectable hormonal contraceptive depo-medroxyprogesterone acetate (DMPA) has been associated
with increased risk of HIV acquisition, but fi ndings are inconsistent. Whether DMPA increases the risk of other
sexually transmitted viral infections is unknown. We assessed the association between DMPA use and incident
herpes simplex virus type 2 (HSV2) infection in women.
Methods In this prospective study, we enrolled HIV-negative and HSV2-negative women aged 15–49 years whose
HIV-negative male partners were concurrently enrolled in a randomised trial of male circumcision in Rakai, Uganda.
We excluded women if either they or their male partners HIV seroconverted. The primary outcome was HSV2
seroconversion, assessed annually. The male circumcision trial was registered with ClinicalTrials.gov, number
NCT00425984.
Findings Between Aug 11, 2003, and July 6, 2006, we enrolled 682 women in this study. We noted HSV2
seroconversions in 70 (10%) women. Incidence was 13·5 per 100 person-years in women consistently using DMPA
(nine incident infections per 66·5 person-years), 4·3 per 100 person-years in pregnant women who were not using
hormonal contraception (18 incident infections per 423·5 person-years), and 6·6 per 100 person-years in women
who were neither pregnant nor using hormonal contraception (35 incident infections per 529·5 person-years).
Women consistently using DMPA had an adjusted hazard ratio for HSV2 seroconversion of 2·26 (95% CI
1·09–4·69; p=0·029) compared with women who were neither pregnant nor using hormonal contraception. Of
132 women with HSV2-seropositive partners, seroconversion was 36·4 per 100 person-years in consistent DMPA
users (four incident infections per 11 person-years) and 10·7 per 100 person-years in women who were neither
pregnant nor using hormonal contraception (11 incident infections per 103 person-years; adjusted hazard ratio
6·23, 95% CI 1·49–26·3; p=0·012).
Interpretation Consistent DMPA use might increase risk of HSV2 seroconversion; however, study power was low.
These fi ndings should be assessed in larger populations with more frequent follow-up than in this study, and other
contraceptive methods should also be assessed. Access to a wide range of highly eff ective contraceptive methods is
needed for women, particularly in sub-Saharan Africa
Tau Neutrinos Underground: Signals of Oscillations with Extragalactic Neutrinos
The appearance of high energy tau neutrinos due to
oscillations of extragalactic neutrinos can be observed by measuring the
neutrino induced upward hadronic and electromagnetic showers and upward muons.
We evaluate quantitatively the tau neutrino regeneration in the Earth for a
variety of extragalactic neutrino fluxes. Charged-current interactions of the
upward tau neutrinos below and in the detector, and the subsequent tau decay
create muons or hadronic and electromagnetic showers. The background for these
events are muon neutrino and electron neutrino charged-current and
neutral-current interactions, where in addition to extragalactic neutrinos, we
consider atmospheric neutrinos. We find significant signal to background ratios
for the hadronic/electromagnetic showers with energies above 10 TeV to 100 TeV
initiated by the extragalactic neutrinos. We show that the tau neutrinos from
point sources also have the potential for discovery above a 1 TeV threshold. A
kilometer-size neutrino telescope has a very good chance of detecting the
appearance of tau neutrinos when both muon and hadronic/electromagnetic showers
are detected.Comment: section added and two new figs; accepted for publication in Physical
Review
Non-Additive Effects of Genotypic Diversity Increase Floral Abundance and Abundance of Floral Visitors
Background: In the emerging field of community and ecosystem genetics, genetic variation and diversity in dominant plant species have been shown to play fundamental roles in maintaining biodiversity and ecosystem function. However, the importance of intraspecific genetic variation and diversity to floral abundance and pollinator visitation has received little attention. Methodology/Principal Findings: Using an experimental common garden that manipulated genotypic diversity (the number of distinct genotypes per plot) of Solidago altissima, we document that genotypic diversity of a dominant plant can indirectly influence flower visitor abundance. Across two years, we found that 1) plant genotype explained 45 % and 92 % of the variation in flower visitor abundance in 2007 and 2008, respectively; and 2) plant genotypic diversity had a positive and non-additive effect on floral abundance and the abundance of flower visitors, as plots established with multiple genotypes produced 25 % more flowers and received 45 % more flower visits than would be expected under an additive model. Conclusions/Significance: These results provide evidence that declines in genotypic diversity may be an important but little considered factor for understanding plant-pollinator dynamics, with implications for the global decline in pollinators due t
Expressions 1984
https://openspace.dmacc.edu/expressions/1008/thumbnail.jp
Intra- and inter-subtype HIV diversity between 1994 and 2018 in southern Uganda: a longitudinal population-based study
There is limited data on human immunodeficiency virus (HIV) evolutionary trends in African populations. We evaluated changes in HIV viral diversity and genetic divergence in southern Uganda over a 24-year period spanning the introduction and scale-up of HIV prevention and treatment programs using HIV sequence and survey data from the Rakai Community Cohort Study, an open longitudinal population-based HIV surveillance cohort. Gag (p24) and env (gp41) HIV data were generated from people living with HIV (PLHIV) in 31 inland semi-urban trading and agrarian communities (1994–2018) and four hyperendemic Lake Victoria fishing communities (2011–2018) under continuous surveillance. HIV subtype was assigned using the Recombination Identification Program with phylogenetic confirmation. Inter-subtype diversity was evaluated using the Shannon diversity index, and intra-subtype diversity with the nucleotide diversity and pairwise TN93 genetic distance. Genetic divergence was measured using root-to-tip distance and pairwise TN93 genetic distance analyses. Demographic history of HIV was inferred using a coalescent-based Bayesian Skygrid model. Evolutionary dynamics were assessed among demographic and behavioral population subgroups, including by migration status. 9931 HIV sequences were available from 4999 PLHIV, including 3060 and 1939 persons residing in inland and fishing communities, respectively. In inland communities, subtype A1 viruses proportionately increased from 14.3% in 1995 to 25.9% in 2017 (P < .001), while those of subtype D declined from 73.2% in 1995 to 28.2% in 2017 (P < .001). The proportion of viruses classified as recombinants significantly increased by nearly four-fold from 12.2% in 1995 to 44.8% in 2017. Inter-subtype HIV diversity has generally increased. While intra-subtype p24 genetic diversity and divergence leveled off after 2014, intra-subtype gp41 diversity, effective population size, and divergence increased through 2017. Intra- and inter-subtype viral diversity increased across all demographic and behavioral population subgroups, including among individuals with no recent migration history or extra-community sexual partners. This study provides insights into population-level HIV evolutionary dynamics following the scale-up of HIV prevention and treatment programs. Continued molecular surveillance may provide a better understanding of the dynamics driving population HIV evolution and yield important insights for epidemic control and vaccine development
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