68 research outputs found
Delayed HIV testing in HIV-positive sub-Saharan Africans
Get PDFThere is evidence that some sub-Saharan African individuals suspect that they are HIV positive before diagnosis but delay being tested for HIV. This increases the likelihood of being diagnosed late (with a severely compromised immune system), a phenomenon that has been observed in sub-Saharan Africans diagnosed in the UK. Late diagnosis has negative personal and public health consequences. There is a lack of understanding of the psychological processes associated with delayed HIV-testing. This study used a Grounded Theory methodology. It aimed to produce a theoretical model to explain the psychological processes associated with delayed HIV testing in sub-Saharan Africans in the UK but also how these processes changed over time and contributed to the decision to test. Seven HIV-positive sub-Saharan African individuals from a London HIV clinic and one from a HIV charity were interviewed about their experiences. Analysis led to the development of a theoretical model of delayed HIV testing. This model consisted of three theoretical codes: moving in and out of uncertainty about HIV infection; preferring not to know HIV status; and making the decision to test for HIV. Participants' HIV risk perception fluctuated and was characterised by uncertainty. This, in combination with a preference to not know their HIV status due to a number of feared consequences of being HIV-positive, deterred them from testing. Participants' thoughts and feelings about knowing their HIV status changed over time. These changes were that they: wanted certainty, had hope of being HIV-negative and/or a hope for treatment and life and preparing for and accepting a potentially positive result. The findings can inform interventions to reduce delayed testing and suggest: a) intervening with ambivalence on an individual level and b) promoting awareness of HIV c) promoting the benefits of testing/costs of not testing at a population level. The findings are discussed in relation to existing research and theory. Strengths and limitations of the study are discussed, as are clinical implications and suggestions for future research
Effects of Prior Herbivory on Aphid Colonization of Solidago Altissima Clones
Get PDFTo determine the effects of genetic variation and initial herbivore damage on Solidago altissima and subsequent aphid colonization, I conducted a common garden experiment with greenhouse-grown clones induced by Trirhabda virgata. Seventy-five days after planting larvae-damaged and undamaged clones in a common garden, I determined Uroleucon nigrotuberculatum abundance, measured plant biomass, and collected leaves for water content, nitrogen, carbon, and terpene analysis. I found significant differences among clones for bornyl acetate, ß-elemene, azulene, ledene oxide, and bicyclo[4.4.0]dec-5-ene, and significant interaction effects between clone and damage for a-pinene, limonene, caryophyllene, and ?-elemene. Some clones, but not others, produced higher quantities of terpenes in plants that had not been previously damaged. Aphid measures were significantly different among clones but were not significantly different between damage. Though SLW, N and C:N were significantly different among clones and between damage, aphid colonization only correlated with terpenes. Aphid abundance was positively related to the sesquiterpenes azulene, ledene oxide, and bicyclo[4.4.0]dec-5-ene. I conclude that U. nigrotuberculatum colonization of S. altissima is due to genetic differences in terpene production among clones, and these differences are affected by prior damage and other environmental factors
Enhanced olfactory sensitivity in autism spectrum conditions
Get PDFBACKGROUND: People with autism spectrum conditions (ASC) report heightened olfaction. Previous sensory experiments in people with ASC have reported hypersensitivity across visual, tactile, and auditory domains, but not olfaction. The aims of the present study were to investigate olfactory sensitivity in ASC, and to test the association of sensitivity to autistic traits. METHODS: We recruited 17 adult males diagnosed with ASC and 17 typical adult male controls and tested their olfactory sensitivity using the Alcohol Sniff Test (AST), a standardised clinical evaluation of olfactory detection. The AST involves varying the distance between subject and stimulus until an odour is barely detected. Participants with ASC also completed the Autism Spectrum Quotient (AQ) as a measure of autism traits. RESULTS: The ASC group detected the odour at a mean distance of 24.1Â cm (SD =11.5) from the nose, compared to the control group, who detected it at a significantly shorter mean distance of 14.4Â cm (SD =5.9). Detection distance was independent of age and IQ for both groups, but showed a significant positive correlation with autistic traits in the ASC group (r =0.522). CONCLUSIONS: This is the first experimental demonstration, as far as the authors are aware, of superior olfactory perception in ASC and showing that greater olfactory sensitivity is correlated with a higher number of autistic traits. This is consistent with results from previous findings showing hypersensitivity in other sensory domains and may help explain anecdotal and questionnaire accounts of heightened olfactory sensitivity in ASC. Results are discussed in terms of possible underlying neurophysiology
Recidivism Treatment for Justice-Involved Veterans: Evaluating Adoption and Sustainment of Moral Reconation Therapy in the US Veterans Health Administration
Get PDFMoral Reconation Therapy (MRT), an evidence-based intervention to reduce risk for criminal recidivism among justice-involved adults, was developed and primarily tested in correctional settings. Therefore, a better understanding of the implementation potential of MRT within non-correctional settings is needed. To address this gap in the literature, we evaluated the adoption and sustainment of MRT in the US Veterans Health Administration (VHA) following a national training initiative in fiscal years 2016 and 2017. In February 2019, surveys with 66 of the 78 VHA facilities that participated in the training were used to estimate the prevalence of MRT adoption and sustainment, and qualitative interviews with key informants from 20 facilities were used to identify factors associated with sustainment of MRT groups. Of the 66 facilities surveyed, the majority reported adopting (n = 52; 79%) and sustaining their MRT group until the time of the survey (n = 38; 58%). MRT sustainment was facilitated by strong intra-facility (e.g., between veterans justice and behavioral health services) and inter-agency collaborations (e.g., between VHA and criminal justice system stakeholders), which provided a reliable referral source to MRT groups, external incentives for patient engagement, and sufficient staffing to maintain groups. Additional facilitators of MRT sustainment were adaptations to the content and delivery of MRT for patients and screening of referrals to the groups. The findings provide guidance to clinics and healthcare systems that are seeking to implement MRT with justice-involved patient populations, and inform development of implementation strategies to be formally tested in future trials
Role of ABCA7 loss-of-function variant in Alzheimer\u27s disease: A replication study in European–Americans
Get PDFINTRODUCTION: A recent study found a significant increase of ABCA7 loss-of-function variants in Alzheimer’s disease (AD) cases compared to controls. Some variants were located on noncoding regions, but it was demonstrated that they affect splicing. Here, we try to replicate the association between AD risk and ABCA7 loss-of-function variants at both the single-variant and gene level in a large and well-characterized European American dataset. METHODS: We genotyped the GWAS common variant and four rare variants previously reported for ABCA7 in 3476 European–Americans. RESULTS: We were not able to replicate the association at the single-variant level, likely due to a lower effect size on the European American population which led to limited statistical power. However, we did replicate the association at the gene level; we found a significant enrichment of ABCA7 loss-of-function variants in AD cases compared to controls (P = 0.0388; odds ratio =1.54). We also confirmed that the association of the loss-of-function variants is independent of the previously reported genome-wide association study signal. CONCLUSIONS: Although the effect size for the association of ABCA7 loss-of-function variants with AD risk is lower in our study (odds ratio = 1.54) compared to the original report (odds ratio = 2.2), the replication of the findings of the original report provides a stronger foundation for future functional applications. The data indicate that different independent signals that modify risk for complex traits may exist on the same locus. Additionally, our results suggest that replication of rare-variant studies should be performed at the gene level rather than focusing on a single variant
Recommended from our members
Legal Services for Veterans (LSV): Protocol for evaluating the grant-based LSV initiative supporting community organizations delivery of legal services to veterans.
Get PDFBACKGROUND: 1.8 million Veterans are estimated to need legal services, such as for housing eviction prevention, discharge upgrades, and state and federal Veterans benefits. While having ones legal needs met is known to improve ones health and its social determinants, many Veterans legal needs remain unmet. Public Law 116-315 enacted in 2021 authorizes VA to fund legal services for Veterans (LSV) by awarding grants to legal service providers including nonprofit organizations and law schools legal assistance programs. This congressionally mandated LSV initiative will award grants to about 75 competitively selected entities providing legal services. This paper describes the protocol for evaluating the initiative. The evaluation will fulfill congressional reporting requirements, and inform continued implementation and sustainment of LSV over time. METHODS: Our protocol calls for a prospective, mixed-methods observational study with a repeated measures design, aligning to the Reach Effectiveness Adoption Implementation Maintenance (RE-AIM) and Integrated Promoting Action on Research Implementation in Health Services (i-PARIHS) frameworks. In 2023, competitively selected legal services-providing organizations will be awarded grants to implement LSV. The primary outcome will be the number of Veterans served by LSV in the 12 months after the awarding of the grant. The evaluation has three Aims. Aim 1 will focus on measuring primary and secondary LSV implementation outcomes aligned to RE-AIM. Aim 2 will apply the mixed quantitative-qualitative Matrixed Multiple Case Study method to identify patterns in implementation barriers, enablers, and other i-PARIHS-aligned factors that relate to observed outcomes. Aim 3 involves a mixed-methods economic evaluation to understand the costs and benefits of LSV implementation. DISCUSSION: The LSV initiative is a new program that VA is implementing to help Veterans who need legal assistance. To optimize ongoing and future implementation of this program, it is important to rigorously evaluate LSVs outcomes, barriers and enablers, and costs and benefits. We have outlined the protocol for such an evaluation, which will lead to recommending strategies and resource allocation for VAs LSV implementation
The relationship between white matter microstructure and general cognitive ability in patients with schizophrenia and healthy participants in the ENIGMA Consortium
Get PDFObjective:
Schizophrenia has recently been associated with widespread white matter microstructural abnormalities, but the functional effects of these abnormalities remain unclear. Widespread heterogeneity of results from studies published to date preclude any definitive characterization of the relationship between white matter and cognitive performance in schizophrenia. Given the relevance of deficits in cognitive function to predicting social and functional outcomes in schizophrenia, the authors carried out a meta-analysis of available data through the ENIGMA Consortium, using a common analysis pipeline, to elucidate the relationship between white matter microstructure and a measure of general cognitive performance, IQ, in patients with schizophrenia and healthy participants.
Methods:
The meta-analysis included 760 patients with schizophrenia and 957 healthy participants from 11 participating ENIGMA Consortium sites. For each site, principal component analysis was used to calculate both a global fractional anisotropy component (gFA) and a fractional anisotropy component for six long association tracts (LA-gFA) previously associated with cognition.
Results:
Meta-analyses of regression results indicated that gFA accounted for a significant amount of variation in cognition in the full sample (effect size [Hedges’ g]=0.27, CI=0.17–0.36), with similar effects sizes observed for both the patient (effect size=0.20, CI=0.05–0.35) and healthy participant groups (effect size=0.32, CI=0.18–0.45). Comparable patterns of association were also observed between LA-gFA and cognition for the full sample (effect size=0.28, CI=0.18–0.37), the patient group (effect size=0.23, CI=0.09–0.38), and the healthy participant group (effect size=0.31, CI=0.18–0.44).
Conclusions:
This study provides robust evidence that cognitive ability is associated with global structural connectivity, with higher fractional anisotropy associated with higher IQ. This association was independent of diagnosis; while schizophrenia patients tended to have lower fractional anisotropy and lower IQ than healthy participants, the comparable size of effect in each group suggested a more general, rather than disease-specific, pattern of association
Cortical morphology in patients with the deficit and non-deficit syndrome of schizophrenia: a worldwide meta- and mega-analyses
Get PDFConverging evidence suggests that schizophrenia (SZ) with primary, enduring negative symptoms (i.e., Deficit SZ (DSZ)) represents a distinct entity within the SZ spectrum while the neurobiological underpinnings remain undetermined. In the largest dataset of DSZ and Non-Deficit (NDSZ), we conducted a meta-analysis of data from 1560 individuals (168 DSZ, 373 NDSZ, 1019 Healthy Controls (HC)) and a mega-analysis of a subsampled data from 944 individuals (115 DSZ, 254 NDSZ, 575 HC) collected across 9 worldwide research centers of the ENIGMA SZ Working Group (8 in the mega-analysis), to clarify whether they differ in terms of cortical morphology. In the meta-analysis, sites computed effect sizes for differences in cortical thickness and surface area between SZ and control groups using a harmonized pipeline. In the mega-analysis, cortical values of individuals with schizophrenia and control participants were analyzed across sites using mixed-model ANCOVAs. The meta-analysis of cortical thickness showed a converging pattern of widespread thinner cortex in fronto-parietal regions of the left hemisphere in both DSZ and NDSZ, when compared to HC. However, DSZ have more pronounced thickness abnormalities than NDSZ, mostly involving the right fronto-parietal cortices. As for surface area, NDSZ showed differences in fronto-parietal-temporo-occipital cortices as compared to HC, and in temporo-occipital cortices as compared to DSZ. Although DSZ and NDSZ show widespread overlapping regions of thinner cortex as compared to HC, cortical thinning seems to better typify DSZ, being more extensive and bilateral, while surface area alterations are more evident in NDSZ. Our findings demonstrate for the first time that DSZ and NDSZ are characterized by different neuroimaging phenotypes, supporting a nosological distinction between DSZ and NDSZ and point toward the separate disease hypothesis
Recommended from our members
Connectome architecture shapes large-scale cortical alterations in schizophrenia: a worldwide ENIGMA study.
Get PDFSchizophrenia is a prototypical network disorder with widespread brain-morphological alterations, yet it remains unclear whether these distributed alterations robustly reflect the underlying network layout. We tested whether large-scale structural alterations in schizophrenia relate to normative structural and functional connectome architecture, and systematically evaluated robustness and generalizability of these network-level alterations. Leveraging anatomical MRI scans from 2439 adults with schizophrenia and 2867 healthy controls from 26 ENIGMA sites and normative data from the Human Connectome Project (n = 207), we evaluated structural alterations of schizophrenia against two network susceptibility models: (i) hub vulnerability, which examines associations between regional network centrality and magnitude of disease-related alterations; (ii) epicenter mapping, which identifies regions whose typical connectivity profile most closely resembles the disease-related morphological alterations. To assess generalizability and specificity, we contextualized the influence of site, disease stages, and individual clinical factors and compared network associations of schizophrenia with that found in affective disorders. Our findings show schizophrenia-related cortical thinning is spatially associated with functional and structural hubs, suggesting that highly interconnected regions are more vulnerable to morphological alterations. Predominantly temporo-paralimbic and frontal regions emerged as epicenters with connectivity profiles linked to schizophrenias alteration patterns. Findings were robust across sites, disease stages, and related to individual symptoms. Moreover, transdiagnostic comparisons revealed overlapping epicenters in schizophrenia and bipolar, but not major depressive disorder, suggestive of a pathophysiological continuity within the schizophrenia-bipolar-spectrum. In sum, cortical alterations over the course of schizophrenia robustly follow brain network architecture, emphasizing marked hub susceptibility and temporo-frontal epicenters at both the level of the group and the individual. Subtle variations of epicenters across disease stages suggest interacting pathological processes, while associations with patient-specific symptoms support additional inter-individual variability of hub vulnerability and epicenters in schizophrenia. Our work outlines potential pathways to better understand macroscale structural alterations, and inter- individual variability in schizophrenia
An Indo-Pacifc coral spawning database
Get PDFThe discovery of multi-species synchronous spawning of scleractinian corals on the Great Barrier Reef in the 1980s stimulated an extraordinary effort to document spawning times in other parts of the globe. Unfortunately, most of these data remain unpublished which limits our understanding of regional and global reproductive patterns. The Coral Spawning Database (CSD) collates much of these disparate data into a single place. The CSD includes 6178 observations (3085 of which were unpublished) of the time or day of spawning for over 300 scleractinian species in 61 genera from 101 sites in the Indo-Pacific. The goal of the CSD is to provide open access to coral spawning data to accelerate our understanding of coral reproductive biology and to provide a baseline against which to evaluate any future changes in reproductive phenology
- …
