160 research outputs found

    Place Cell Networks in Pre-weanling Rats Show Associative Memory Properties from the Onset of Exploratory Behavior

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    Place cells are hippocampal pyramidal cells that are active when an animal visits a restricted area of the environment, and collectively their activity constitutes a neural representation of space. Place cell populations in the adult rat hippocampus display fundamental properties consistent with an associative memory network: the ability to 1) generate new and distinct spatial firing patterns when encountering novel spatial contexts or changes in sensory input ("remapping") and 2) reinstate previously stored firing patterns when encountering a familiar context, including on the basis of an incomplete/degraded set of sensory cues ("pattern completion"). To date, it is unknown when these spatial memory responses emerge during brain development. Here, we show that, from the age of first exploration (postnatal day 16) onwards, place cell populations already exhibit these key features: they generate new representations upon exposure to a novel context and can reactivate familiar representations on the basis of an incomplete set of sensory cues. These results demonstrate that, as early as exploratory behaviors emerge, and despite the absence of an adult-like grid cell network, the developing hippocampus processes incoming sensory information as an associative memory network

    Meal-derived glucagon responses are related to lower hepatic phosphate concentrations in obesity and type 2 diabetes

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    Aim. - Type 2 diabetes (T2D) alters glucagon, glucagon-like peptide (GLP)-1, glucose-dependent insulinotropic polypeptide (GIP) and hepatic energy metabolism, yet the possible relationships remain unclear.Methods. - In this observational study, lean insulin-sensitive control subjects (BMI: 23.2 +/- 1.5 kg/m(2)), age-matched insulin-resistant obese subjects (BMI: 34.3 +/- 1.7 kg/m(2)) and similarly obese elderly T2D patients (BMI: 32.0 +/- 2.4 kg/m(2)) underwent mixed-meal tolerance tests (MMTTs), and assessment of hepatic gamma ATP, inorganic phosphate (P-i) and lipids using P-31/H-1 magnetic resonance spectroscopy. Meal-induced secretion of glucagon and incretins was calculated from incremental areas under the concentration-time curves (iAUCs). Peripheral and adipose tissue insulin sensitivity were assessed from time courses of circulating glucose, insulin and free fatty acids.Results. - MMTT-derived peripheral insulin sensitivity was lowest in T2D patients (P &lt;0.001), while glucagon concentrations were comparable across all three groups. At 260 min, GLP-1 was lower in T2D patients than in controls, whereas GIP was lowest in obese individuals. Fasting glucagon concentrations correlated positively with fasting (r = 0.60) and postprandial hepatocellular lipid levels (160 min: r= 0.51, 240 min: r = 0.59), and negatively with adipose tissue insulin sensitivity (r = -0.73). Higher meal-induced glucagon release (iAUC(0)(-260) (min)) correlated with lower fasting (r = -0.62) and postprandial P(i )levels (160 min: r = -0.43, 240 min: r = -0.42; all P &lt;0.05). Higher meal-induced release of GIP (iAUC(0-260) (min)) correlated positively with fasting (r = 0.54) and postprandial serum triglyceride concentrations (iAUC(0-260 min, )r = 0.54; all P &lt;0.01).Conclusion. - Correlations between fasting glucagon and hepatic lipids and between meal-induced glucagon and hepatic P-i suggest a role for glucagon in hepatic energy metabolism. (C) 2018 Elsevier Masson SAS. All rights reserved.</p

    Dynamic, reversible oxidative addition of highly polar bonds to a transition metal

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    The combination of Pt0 complexes and indium trihalides leads to compounds that form equilibria in solution between their In-X oxidative addition (OA) products (PtII indyl complexes) and their metal-only Lewis pair (MOLP) isomers (LnPt→InX3). The position of the equilibria can be altered reversibly by changing the solvent, while the equilibria can be reversibly and irreversibly driven towards the MOLP products by addition of further donor ligands. The results mark the first observation of an equilibrium between MOLP and OA isomers, as well as the most polar bond ever observed to undergo reversible oxidative addition to a metal complex. In addition, we present the first structural characterization of MOLP and oxidative addition isomers of the same compound. The relative energies of the MOLP and OA isomers were calculated by DFT methods, and the possibility of solvent-mediated isomerization is discussed

    HIV and Syphilis Testing Preferences among Men Who Have Sex with Men in South China: A Qualitative Analysis to Inform Sexual Health Services

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    BackgroundHealth services for men who have sex with men (MSM) are inadequate in many areas around the world. HIV and syphilis test uptake remain suboptimal among MSM in China and many other regions. To inform the development of more comprehensive sexually transmitted disease (STD) testing programs among MSM, we collected descriptive data on MSM testing practices and preferences.MethodsMSM in two large urban Chinese cities were recruited through community-based organizations and clinics to participate in semi-structured interviews. We purposively sampled MSM across a range of sociodemographic characteristics and testing history, and assessed preferences for HIV and syphilis testing in the context of facilitators and barriers to testing and previous testing experiences. Each interview transcript was coded and thematically analyzed using Atlas.ti 7.0.Results35 MSM were interviewed. Confidentiality and privacy were the most important factors influencing participants’ decisions about whether and where to get tested. Men preferred rapid testing (results available within 30 minutes) compared to conventional tests where results take several hours or days to return. Participants described concerns about quality and accuracy of rapid tests offered in non-clinical settings such as community-based organizations. Men preferred testing service providers who were MSM-friendly, non-discriminatory, and medically trained. Preferred service center environments included: convenient but discrete location, MSM-friendly atmosphere, and clean/standard medical facilities.ConclusionOur data highlight the need for HIV/syphilis testing services that are confidential and inclusive of MSM. Rapid testing in decentralized (i.e. peripheral health facilities and community-level, non-clinical venues) settings provides an opportunity to reach individuals who have not been tested before, but must be accompanied by quality assurance systems and technical competence. Implementation research could further evaluate HIV/syphilis testing programs responsive to MSM preferences.Short SummaryA qualitative study of MSM in South China found that men preferred rapid STD testing at MSM-focused test centers, but were concerned about test quality assurance and confidentiality

    Clinical Frailty Scale (CFS) reliably stratifies octogenarians in German ICUs: a multicentre prospective cohort study

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    Background: In intensive care units (ICU) octogenarians become a routine patients group with aggravated therapeutic and diagnostic decision-making. Due to increased mortality and a reduced quality of life in this high-risk population, medical decision-making a fortiori requires an optimum of risk stratification. Recently, the VIP-1 trial prospectively observed that the clinical frailty scale (CFS) performed well in ICU patients in overall-survival and short-term outcome prediction. However, it is known that healthcare systems differ in the 21 countries contributing to the VIP-1 trial. Hence, our main focus was to investigate whether the CFS is usable for risk stratification in octogenarians admitted to diversified and high tech German ICUs. Methods: This multicentre prospective cohort study analyses very old patients admitted to 20 German ICUs as a sub-analysis of the VIP-1 trial. Three hundred and eight patients of 80 years of age or older admitted consecutively to participating ICUs. CFS, cause of admission, APACHE II, SAPS II and SOFA scores, use of ICU resources and ICU- and 30-day mortality were recorded. Multivariate logistic regression analysis was used to identify factors associated with 30-day mortality. Results: Patients had a median age of 84 [IQR 82–87] years and a mean CFS of 4.75 (± 1.6 standard-deviation) points. More than half of the patients (53.6%) were classified as frail (CFS ≥ 5). ICU-mortality was 17.3% and 30-day mortality was 31.2%. The cause of admission (planned vs. unplanned), (OR 5.74) and the CFS (OR 1.44 per point increase) were independent predictors of 30-day survival. Conclusions: The CFS is an easy determinable valuable tool for prediction of 30-day ICU survival in octogenarians, thus, it may facilitate decision-making for intensive care givers in Germany. Trial registration: The VIP-1 study was retrospectively registered on ClinicalTrials.gov (ID: NCT03134807 ) on May 1, 2017

    An instant messaging mobile phone application for promoting HIV pre-exposure prophylaxis uptake among Chinese gay, bisexual and other men who have sex with men: A mixed methods feasibility and piloting randomized controlled trial study

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    Background Mobile health (mHealth) is a promising intervention mode for HIV prevention, but little is known about its feasibility and effects in promoting pre-exposure prophylaxis (PrEP) uptake among Chinese gay, bisexual and other men who have sex with men (GBMSM). Methods We evaluated an instant messaging application using a WeChat-based mini-app to promote PrEP uptake among GBMSM via a mixed-methods design that includes a 12-week, two-arm randomized controlled pilot trial and in-depth progress interviews in Guangzhou, China. Primary outcomes include the number of PrEP initiations, individual-level psychosocial variables related to PrEP initiation, and usability of the PrEP mini-app. Results Between November 2020 and April 2021, 70 GBMSM were successfully enrolled and randomized into two arms at 2:1 ratio (46 to the intervention arm, 24 to the control arm). By the end of 12-week follow-up, 22 (31.4%) participants completed the initial consultation and lab tests for PrEP, and 13 (18.6%) filled their initial PrEP prescription. We observed modest but non-significant improvements in participants’ intention to use PrEP, actual PrEP initiation, PrEP-related self-efficacy, stigma, and attitudes over 12 weeks when comparing the mini-app and the control arms. Qualitative interviews revealed the key barriers to PrEP uptake include anticipated stigma and discrimination in clinical settings, burden of PrEP care, and limited operating hours of the PrEP clinic. In-person clinic navigation support was highly valued. Conclusions This pilot trial of a mobile phone-based PrEP mini-app demonstrated feasibility and identified limitations in facilitating PrEP uptake among Chinese GBMSM. Future improvements may include diversifying the content presentation in engaging media formats, adding user engagement features, and providing off-line in-clinic navigation support during initial PrEP visit. More efforts are needed to understand optimal strategies to identify and implement alternative PrEP provision models especially in highly stigmatized settings with diverse needs. Trial registration Trial registration: The study was prospectively registered on clinicaltrials.gov (NCT04426656) on 11 June, 2020

    A Men Who Have Sex With Men-Friendly Doctor Finder Hackathon in Guangzhou, China: Development of a Mobile Health Intervention to Enhance Health Care Utilization.

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    BACKGROUND: Mobile health (mHeath)-based HIV and sexual health promotion among men who have sex with men (MSM) is feasible in low- and middle-income settings. However, many currently available mHealth tools on the market were developed by the private sector for profit and have limited input from MSM communities. OBJECTIVE: A health hackathon is an intensive contest that brings together participants from multidisciplinary backgrounds to develop a proposed solution for a specific health issue within a short period. The purpose of this paper was to describe a hackathon event that aimed to develop an mHealth tool to enhance health care (specifically HIV prevention) utilization among Chinese MSM, summarize characteristics of the final prototypes, and discuss implications for future mHealth intervention development. METHODS: The hackathon took place in Guangzhou, China. An open call for hackathon participants was advertised on 3 Chinese social media platforms, including Blued, a popular social networking app among MSM. All applicants completed a Web-based survey and were then scored. The top scoring applicants were grouped into teams based on their skills and content area expertise. Each team was allowed 1 month to prepare for the hackathon. The teams then came together in person with on-site expert mentorship for a 72-hour hackathon contest to develop and present mHealth prototype solutions. The judging panel included experts in psychology, public health, computer science, social media, clinical medicine, and MSM advocacy. The final prototypes were evaluated based on innovation, usability, and feasibility. RESULTS: We received 92 applicants, and 38 of them were selected to attend the April 2019 hackathon. A total of 8 teams were formed, including expertise in computer science, user interface design, business or marketing, clinical medicine, and public health. Moreover, 24 participants self-identified as gay, and 3 participants self-identified as bisexual. All teams successfully developed a prototype tool. A total of 4 prototypes were designed as a mini program that could be embedded within a popular Chinese social networking app, and 3 prototypes were designed as stand-alone apps. Common prototype functions included Web-based physician searching based on one's location (8 prototypes), health education (4 prototypes), Web-based health counseling with providers or lay health volunteers (6 prototypes), appointment scheduling (8 prototypes), and between-user communication (2 prototypes). All prototypes included strategies to ensure privacy protection for MSM users, and some prototypes offered strategies to ensure privacy of physicians. The selected prototypes are undergoing pilot testing. CONCLUSIONS: This study demonstrated the feasibility and acceptability of using a hackathon to create mHealth intervention tools. This suggests a different pathway to developing mHealth interventions and could be relevant in other settings

    Champion and audit and feedback strategy fidelity and their relationship to depression intervention fidelity: A mixed method study

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    Background: Globally, mental health disorders rank as the greatest cause of disability. Low and middle-income countries (LMICs) hold a disproportionate share of the mental health burden, especially as it pertains to depression. Depression is highly prevalent among those with non-communicable diseases (NCDs), creating a barrier to successful treatment. While some treatments have proven efficacy in LMIC settings, wide dissemination is challenged by multiple factors, leading researchers to call for implementation strategies to overcome barriers to care provision. However, implementation strategies are often not well defined or documented, challenging the interpretation of study results and the uptake and replication of strategies in practice settings. Assessing implementation strategy fidelity (ISF), or the extent to which a strategy was implemented as designed, overcomes these challenges. This study assessed fidelity of two implementation strategies (a ‘basic’ champion strategy and an ‘enhanced’ champion ​+ ​audit and feedback strategy) to improve the integration of a depression intervention, measurement based care (MBC), at 10 NCD clinics in Malawi. The primary goal of this study was to assess the relationship between the implementation strategies and MBC fidelity using a mixed methods approach. Methods: We developed a theory-informed mixed methods fidelity assessment that first combined an implementation strategy specification technique with a fidelity framework. We then created corresponding fidelity indicators to strategy components. Clinical process data and one-on-one in-depth interviews with 45 staff members at 6 clinics were utilized as data sources. Our final analysis used descriptive statistics, reflexive-thematic analysis (RTA), data merging, and triangulation to examine the relationship between ISF and MBC intervention fidelity. Results: Our mixed methods analysis revealed how ISF may moderate the relationship between the strategies and MBC fidelity. Leadership engagement and implementation climate were critical for clinics to overcome implementation barriers and preserve implementation strategy and MBC fidelity. Descriptive statistics determined champion strategy fidelity to range from 61 to 93% across the 10 clinics. Fidelity to the audit and feedback strategy ranged from 82 to 91% across the 5 clinics assigned to that condition. MBC fidelity ranged from 54 to 95% across all clinics. Although correlations between ISF and MBC fidelity were not statistically significant due to the sample of 10 clinics, associations were in the expected direction and of moderate effect size. A coefficient for shared depression screening among clinicians had greater face validity compared to depression screening coverage and functioned as a proximal indicator of implementation strategy success. Conclusion: Fidelity to the basic and enhanced strategies varied by site and were influenced by leadership engagement and implementation climate. Champion strategies may benefit from the addition of leadership strategies to help address implementation barriers outside the purview of champions. ISF may moderate the relationship between strategies and implementation outcomes

    Willingness to act upon beliefs about 'treatment as prevention' among Australian gay and bisexual men

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    HIV 'treatment as prevention' (TasP) is highly effective in reducing HIV transmission in serodiscordant couples. There has been little examination of gay and bisexual men's attitudes towards TasP, particularly regarding men's willingness to act on beliefs about TasP. We conducted an online cross-sectional survey of Australian men in late 2012 to investigate knowledge and beliefs about new developments in HIV prevention. Amongst 839 men (mean age 39.5 years), men tended to disagree that TasP was sufficiently effective to justify reduced condom use, although HIV-positive men had more favourable attitudes. Only a minority of men were aware of any evidence for TasP; and one-quarter incorrectly believed that evidence for the effectiveness of TasP already existed for the homosexual population. One-fifth (20.5%) of men reported that they would be willing to have condomless anal intercourse with an opposite-status sexual partner when the HIV-positive partner was taking HIV treatments. Factors independently associated with such willingness were: HIV-positive serostatus, reporting any serodiscordant or serononconcordant condomless anal intercourse with a regular male partner in the previous six months, reporting any condomless anal intercourse with a casual male partner in the previous six months, and having greater beliefs in the effectiveness of TasP. This indicated that the men most willing to rely on TasP to prevent transmission were already engaging in higher risk practices. Biomedical HIV prevention represents a rapidly changing environment with new research as well as community and policy responses emerging at a fast pace. For men with serodiscordant sexual partners to successfully apply TasP to reducing transmission risk, more support and education is needed to enable better utilisation of TasP in specific relational and sexual contexts

    Developing a mHealth intervention to promote uptake of HIV testing among African communities in the UK: a qualitative study

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    Background: HIV-related mHealth interventions have demonstrable efficacy in supporting treatment adherence, although the evidence base for promoting HIV testing is inconclusive. Progress is constrained by a limited understanding of processes used to develop interventions and weak theoretical underpinnings. This paper describes a research project that informed the development of a theory-based mHealth intervention to promote HIV testing amongst city-dwelling African communities in the UK. Methods: A community-based participatory social marketing design was adopted. Six focus groups (48 participants in total) were undertaken and analysed using a thematic framework approach, guided by constructs from the Health Belief Model. Key themes were incorporated into a set of text messages, which were pre-tested and refined. Results: The focus groups identified a relatively low perception of HIV risk, especially amongst men, and a range of social and structural barriers to HIV testing. In terms of self-efficacy around HIV testing, respondents highlighted a need for communities and professionals to work together to build a context of trust through co-location in, and co-involvement of, local communities which would in turn enhance confidence in, and support for, HIV testing activities of health professionals. Findings suggested that messages should: avoid an exclusive focus on HIV, be tailored and personalised, come from a trusted source, allay fears and focus on support and health benefits. Conclusions: HIV remains a stigmatized and de-prioritized issue within African migrant communities in the UK, posing barriers to HIV testing initiatives. A community-based participatory social marketing design can be successfully used to develop a culturally appropriate text messaging HIV intervention. Key challenges involved turning community research recommendations into brief text messages of only 160 characters. The intervention needs to be evaluated in a randomized control trial. Future research should explore the application of the processes and methodologies described in this paper within other communities
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