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"Bock, Peter"
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Patient-Reported Barriers to Adherence to Antiretroviral Therapy: A Systematic Review and Meta-Analysis
by
Appolo, Tsitsi
,
Nachega, Jean B.
,
Doherty, Meg
in
Acquired immune deficiency syndrome
,
AIDS
,
Alcohol
2016
Maintaining high levels of adherence to antiretroviral therapy (ART) is a challenge across settings and populations. Understanding the relative importance of different barriers to adherence will help inform the targeting of different interventions and future research priorities.
We searched MEDLINE via PubMed, Embase, Web of Science, and PsychINFO from 01 January 1997 to 31 March 2016 for studies reporting barriers to adherence to ART. We calculated pooled proportions of reported barriers to adherence per age group (adults, adolescents, and children). We included data from 125 studies that provided information about adherence barriers for 17,061 adults, 1,099 children, and 856 adolescents. We assessed differences according to geographical location and level of economic development. The most frequently reported individual barriers included forgetting (adults 41.4%, 95% CI 37.3%-45.4%; adolescents 63.1%, 95% CI 46.3%-80.0%; children/caregivers 29.2%, 95% CI 20.1%-38.4%), being away from home (adults 30.4%, 95% CI 25.5%-35.2%; adolescents 40.7%, 95% CI 25.7%-55.6%; children/caregivers 18.5%, 95% CI 10.3%-26.8%), and a change to daily routine (adults 28.0%, 95% CI 20.9%-35.0%; adolescents 32.4%, 95% CI 0%-75.0%; children/caregivers 26.3%, 95% CI 15.3%-37.4%). Depression was reported as a barrier to adherence by more than 15% of patients across all age categories (adults 15.5%, 95% CI 12.8%-18.3%; adolescents 25.7%, 95% CI 17.7%-33.6%; children 15.1%, 95% CI 3.9%-26.3%), while alcohol/substance misuse was commonly reported by adults (12.9%, 95% CI 9.7%-16.1%) and adolescents (28.8%, 95% CI 11.8%-45.8%). Secrecy/stigma was a commonly cited barrier to adherence, reported by more than 10% of adults and children across all regions (adults 13.6%, 95% CI 11.9%-15.3%; children/caregivers 22.3%, 95% CI 10.2%-34.5%). Among adults, feeling sick (15.9%, 95% CI 13.0%-18.8%) was a more commonly cited barrier to adherence than feeling well (9.3%, 95% CI 7.2%-11.4%). Health service-related barriers, including distance to clinic (adults 17.5%, 95% CI 13.0%-21.9%) and stock outs (adults 16.1%, 95% CI 11.7%-20.4%), were also frequently reported. Limitations of this review relate to the fact that included studies differed in approaches to assessing adherence barriers and included variable durations of follow up. Studies that report self-reported adherence will likely underestimate the frequency of non-adherence. For children, barriers were mainly reported by caregivers, which may not correspond to the most important barriers faced by children.
Patients on ART face multiple barriers to adherence, and no single intervention will be sufficient to ensure that high levels of adherence to treatment and virological suppression are sustained. For maximum efficacy, health providers should consider a more triaged approach that first identifies patients at risk of poor adherence and then seeks to establish the support that is needed to overcome the most important barriers to adherence.
Journal Article
A Guide to Elucidate the Hidden Multicomponent Layered Structure of Plant Cuticles by Raman Imaging
by
Gierlinger, Notburga
,
Felhofer, Martin
,
Mayer, Konrad
in
chalcones
,
Chemical composition
,
Chemistry
2021
The cuticle covers almost all plant organs as the outermost layer and serves as a transpiration barrier, sunscreen, and first line of defense against pathogens. Waxes, fatty acids, and aromatic components build chemically and structurally diverse layers with different functionality. So far, electron microscopy has elucidated structure, while isolation, extraction, and analysis procedures have revealed chemistry. With this method paper, we close the missing link by demonstrating how Raman microscopy gives detailed information about chemistry and structure of the native cuticle on the microscale. We introduce an optimized experimental workflow, covering the whole process of sample preparation, Raman imaging experiment, data analysis, and interpretation and show the versatility of the approach on cuticles of a spruce needle, a tomato peel, and an Arabidopsis stem. We include laser polarization experiments to deduce the orientation of molecules and multivariate data analysis to separate cuticle layers and verify their molecular composition. Based on the three investigated cuticles, we discuss the chemical and structural diversity and validate our findings by comparing models based on our spectroscopic data with the current view of the cuticle. We amend the model by adding the distribution of cinnamic acids and flavonoids within the cuticle layers and their transition to the epidermal layer. Raman imaging proves as a non-destructive and fast approach to assess the chemical and structural variability in space and time. It might become a valuable tool to tackle knowledge gaps in plant cuticle research.
Journal Article
Raman imaging reveals in-situ microchemistry of cuticle and epidermis of spruce needles
by
Gierlinger, Notburga
,
Sasani, Nadia
,
Felhofer, Martin
in
Algorithms
,
Aromatic compounds
,
Biological Techniques
2021
Background
The cuticle is a protective layer playing an important role in plant defense against biotic and abiotic stresses. So far cuticle structure and chemistry was mainly studied by electron microscopy and chemical extraction. Thus, analysing composition involved sample destruction and the link between chemistry and microstructure remained unclear. In the last decade, Raman imaging showed high potential to link plant anatomical structure with microchemistry and to give insights into orientation of molecules. In this study, we use Raman imaging and polarization experiments to study the native cuticle and epidermal layer of needles of Norway spruce, one of the economically most important trees in Europe. The acquired hyperspectral dataset is the basis to image the chemical heterogeneity using univariate (band integration) as well as multivariate data analysis (cluster analysis and non-negative matrix factorization).
Results
Confocal Raman microscopy probes the cuticle together with the underlying epidermis in the native state and tracks aromatics, lipids, carbohydrates and minerals with a spatial resolution of 300 nm. All three data analysis approaches distinguish a waxy, crystalline layer on top, in which aliphatic chains and coumaric acid are aligned perpendicular to the surface. Also in the lipidic amorphous cuticle beneath, strong signals of coumaric acid and flavonoids are detected. Even the unmixing algorithm results in mixed endmember spectra and confirms that lipids co-locate with aromatics. The underlying epidermal cell walls are devoid of lipids but show strong aromatic Raman bands. Especially the upper periclinal thicker cell wall is impregnated with aromatics. At the interface between epidermis and cuticle Calcium oxalate crystals are detected in a layer-like fashion. Non-negative matrix factorization gives the purest component spectra, thus the best match with reference spectra and by this promotes band assignments and interpretation of the visualized chemical heterogeneity.
Conclusions
Results sharpen our view about the cuticle as the outermost layer of plants and highlight the aromatic impregnation throughout. In the future, developmental studies tracking lipid and aromatic pathways might give new insights into cuticle formation and comparative studies might deepen our understanding why some trees and their needle and leaf surfaces are more resistant to biotic and abiotic stresses than others.
Journal Article
Clinical and Radiological Results of a Human Bone Graft Screw in Tarsometatarsal II/+III Arthrodesis
2022
Category:
Midfoot/Forefoot
Introduction/Purpose:
Osteoarthritis of the lesser Lisfranc joints is a debilitating foot condition. Arthrodesis is a well known procedure to eliviate pain and improve quality of life of the affected person. The use of a transplant screw made of allogenic human bone material is considered a new technique for lesser Lisfranc joint arthrodesis. This article investigates the clinical outcome and radiological integration of the allogenic bone screw for arthrodesis of the tarsometatarsal joints II/+III.
Methods:
This is a prospective study involving 20 feet of 17 patients who received TMT II/+III arthrodesis with an allogenic bone screw. A Visual Analogue Scale (VAS pain and function), Foot Function Index (FFI), American Orthopaedic Foot & Ankle Society Outcome Score (AOFAS) and Foot and Ankle Outcome Score (FAOS) were used as measures to compare preoperative with postoperative results. Radiologic integration in the recipient bone was also evaluated.
Results:
A significant mean pre- to postoperative improvement of all evaluated scores has been observed (P< .05) after a mean follow-up of 16 months (12-33). VAS (pain) decreased from 7.6 points to 1.4 points, VAS (function) from 7.25 points to 1.8 points. The FFI improved from 62.3% to 16.7%, the AOFAS score from 29.7 points to 79.9 points of the. In all surveyed subscales of the FAOS score an increase was observed: symptoms: 55.2 to 85.6; pain: 30.5 to 86.9; function: 33.1 to 88.3; quality of life: 27.8 to 79.7. The radiologic evaluation did not show any pseudarthrosis at last follow-up. Moreover, in 19 of 20 feet (95%) a complete radiological integration of the screw into the receiving bone was seen after a minimum follow-up time of 12 months and was no longer distinguishable from the original bone.
Conclusion:
With these first results of the use of an allogenic bone screw in TMT II/+III arthrodesis, a significant improvement from preoperative to postoperative clinical status was confirmed and a full radiographic integration demonstrated in all feet.
Journal Article
Better Antiretroviral Therapy Outcomes at Primary Healthcare Facilities: An Evaluation of Three Tiers of ART Services in Four South African Provinces
by
Bock, Peter
,
Fatti, Geoffrey
,
Grimwood, Ashraf
in
Acquired immune deficiency syndrome
,
Adolescent
,
Adult
2010
There are conflicting reports of antiretroviral therapy (ART) effectiveness comparisons between primary healthcare (PHC) facilities and hospitals in low-income settings. This comparison has not been evaluated on a broad scale in South Africa.
A retrospective cohort study was conducted including ART-naïve adults from 59 facilities in four provinces in South Africa, enrolled between 2004 and 2007. Kaplan-Meier estimates, competing-risks Cox regression, generalised estimating equation population-averaged models and logistic regression were used to compare death, loss to follow-up (LTFU) and virological suppression (VS) between PHC, district and regional hospitals. 29 203 adults from 47 PHC facilities, nine district hospitals and three regional hospitals were included. Patients at PHC facilities had more advanced WHO stage disease when starting ART. Retention in care was 80.1% (95% CI: 79.3%-80.8%), 71.5% (95% CI: 69.1%-73.8%) and 68.7% (95% CI: 67.0%-69.7%) at PHC, district and regional hospitals respectively, after 24 months of treatment (P<0.0001). In adjusted regression analyses, LTFU was independently increased at regional hospitals (aHR 2.19; 95% CI: 1.94-2.47) and mortality was independently elevated at district hospitals (aHR 1.60; 95% CI: 1.30-1.99) compared to PHC facilities after 12 months of ART. District and regional hospital patients had independently reduced probabilities of VS, aOR 0.76 (95% CI: 0.59-0.97) and 0.64 (95% CI: 0.56-0.75) respectively compared to PHC facilities over 24 months of treatment.
ART outcomes were superior at PHC facilities, despite PHC patients having more advanced clinical stage disease when starting ART, suggesting that ART can be adequately provided at this level and supporting the South African government's call for rapid up-scaling of ART at the primary level of care. Further prospective research is required to determine the degree to which outcome differences are attributable to either facility level characteristics or patient co-morbidity at hospital level.
Journal Article
A universal testing and treatment intervention to improve HIV control: One-year results from intervention communities in Zambia in the HPTN 071 (PopART) cluster-randomised trial
by
Beyers, Nulda
,
Bock, Peter
,
Griffith, Sam
in
Acceptance
,
Acceptance tests
,
Acquired immune deficiency syndrome
2017
The Joint United Nations Programme on HIV/AIDS (UNAIDS) 90-90-90 targets require that, by 2020, 90% of those living with HIV know their status, 90% of known HIV-positive individuals receive sustained antiretroviral therapy (ART), and 90% of individuals on ART have durable viral suppression. The HPTN 071 (PopART) trial is measuring the impact of a universal testing and treatment intervention on population-level HIV incidence in 21 urban communities in Zambia and South Africa. We report observational data from four communities in Zambia to assess progress towards the UNAIDS targets after 1 y of the PopART intervention.
The PopART intervention comprises annual rounds of home-based HIV testing delivered by community HIV-care providers (CHiPs) who also support linkage to care, ART retention, and other services. Data from four communities in Zambia receiving the full intervention (including immediate ART for all individuals with HIV) were used to determine proportions of participants who knew their HIV status after the CHiP visit; proportions linking to care and initiating ART following referral; and overall proportions of HIV-infected individuals who knew their status (first 90 target) and the proportion of these on ART (second 90 target), pre- and post-intervention. We are not able to assess progress towards the third 90 target at this stage of the study. Overall, 121,130 adults (59,283 men and 61,847 women) were enumerated in 46,714 households during the first annual round (December 2013 to June 2015). Of the 45,399 (77%) men and 55,703 (90%) women consenting to the intervention, 80% of men and 85% of women knew their HIV status after the CHiP visit. Of 6,197 HIV-positive adults referred by CHiPs, 42% (95% CI: 40%-43%) initiated ART within 6 mo and 53% (95% CI: 52%-55%) within 12 mo. In the entire population, the estimated proportion of HIV-positive adults who knew their status increased from 52% to 78% for men and from 56% to 87% for women. The estimated proportion of known HIV-positive individuals on ART increased overall from 54% after the CHiP visit to 74% by the end of the round for men and from 53% to 73% for women. The estimated overall proportion of HIV-positive adults on ART, irrespective of whether they knew their status, increased from 44% to 61%, compared with the 81% target (the product of the first two 90 targets). Coverage was lower among young men and women than in older age groups. The main limitation of the study was the need for assumptions concerning knowledge of HIV status and ART coverage among adults not consenting to the intervention or HIV testing, although our conclusions were robust in sensitivity analyses.
In this analysis, acceptance of HIV testing among those consenting to the intervention was high, although linkage to care and ART initiation took longer than expected. Knowledge of HIV-positive status increased steeply after 1 y, almost attaining the first 90 target in women and approaching it in men. The second 90 target was more challenging, with approximately three-quarters of known HIV-positive individuals on ART by the end of the annual round. Achieving higher test uptake in men and more rapid linkage to care will be key objectives during the second annual round of the intervention.
ClinicalTrials.gov NCT01900977.
Journal Article
From the Soft to the Hard: Changes in Microchemistry During Cell Wall Maturation of Walnut Shells
by
Gierlinger, Notburga
,
Bock, Peter
,
Staedler, Yannick Marc
in
Analytical chemistry
,
Biomimetic materials
,
Biomimetics
2020
The walnut shell is a hard and protective layer that provides an essential barrier between the seed and its environment. The shell is based on only one unit cell type: the polylobate sclerenchyma cell. For a better understanding of the interlocked walnut shell tissue, we investigate the structural and compositional changes during the development of the shell from the soft to the hard state. Structural changes at the macro level are explored by X-ray tomography and on the cell and cell wall level various microscopic techniques are applied. Walnut shell development takes place beneath the outer green husk, which protects and delivers components during the development of the walnut. The cells toward this outer green husk have the thickest and most lignified cell walls. With maturation secondary cell wall thickening takes place and the amount of all cell wall components (cellulose, hemicelluloses and especially lignin) is increased as revealed by FTIR microscopy. Focusing on the cell wall level, Raman imaging showed that lignin is deposited first into the pectin network between the cells and cell corners, at the very beginning of secondary cell wall formation. Furthermore, Raman imaging of fluorescence visualized numerous pits as a network of channels, connecting all the interlocked polylobate walnut shells. In the final mature stage, fluorescence increased throughout the cell wall and a fluorescent layer was detected toward the lumen in the inner part. This accumulation of aromatic components is reminiscent of heartwood formation of trees and is suggested to improve protection properties of the mature walnut shell. Understanding the walnut shell and its development will inspire biomimetic material design and packaging concepts, but is also important for waste valorization, considering that walnuts are the most widespread tree nuts in the world.
Journal Article
HIV and gender identity expression among transfeminine people in the Western Cape, South Africa – a thematic analysis of data from the HPTN 071 (PopART) trial
2024
Introduction
Transfeminine people in South Africa have a high HIV risk due to structural, behavioural, and psychosocial factors. Transfeminine people and feminine identifying men who have sex with men (MSM) are often conflated or grouped with transgender or MSM categories in HIV service programming, although they don’t necessarily identify as either. We aimed to investigate gender expression among feminine identifying people who were assigned male at birth. We examined how local conceptualizations of sexuality and gender intersect with the key population label of ‘transgender’ imported into local HIV programming.
Methods
A qualitative cohort nested within the HPTN 071 (PopART) trial included longitudinal, in-depth interviews with eight transfeminine people (four who disclosed as living with HIV). Data were collected approximately every six weeks between January 2016 and October 2017. We used a combination of thematic analysis and case study descriptions to explore gender identification among participants.
Results
Of the eight participants, only one accepted ‘transgender’ as a label, and even she used varying terms at different times to describe her identity. For participants, a feminine identity included dressing in normatively feminine clothes; using feminine terms, pronouns and names; and adopting stereotypically feminine mannerisms. Participants would switch between typically feminine and masculine norms in response to contextual cues and audience. For example, some participants accepted identification as masculine gay men amongst their family members. Among peers, they expressed their identity through typically more effeminate gender characteristics, for example self-identifying as “femgay”. With partners they often also took on a feminine identity role, for example identifying as women in sexual and romantic relationships (meaning they viewed and expressed themselves as the feminine partner in the relationship).
Conclusions
Our findings are amongst the first exploratory and descriptive data of transfeminine people in South Africa. We show how transfeminine people navigate fluid gender identities that could pose a challenge for accessing and utilizing HIV services that are currently set up for transgender individuals or MSM. More work needs to be done to understand and respond to the diverse and shifting ways people experience their gender identities in this high HIV burden context.
Journal Article
Towards 90-90: Findings after two years of the HPTN 071 (PopART) cluster-randomized trial of a universal testing-and-treatment intervention in Zambia
by
Beyers, Nulda
,
MacLeod, David
,
Bock, Peter
in
Acquired immune deficiency syndrome
,
Adolescent
,
Adult
2018
HPTN071(PopART) is a 3-arm community-randomised study in 21 peri-urban/urban communities in Zambia and the Western Cape of South Africa, with high HIV prevalence and high mobility especially among young adults. In Arm A communities, from November 2013 community HIV care providers (CHiPs) have delivered the \"PopART\" universal-test-and-treat (UTT) package in annual rounds, during which they visit all households and offer HIV testing. CHiPs refer HIV-positive (HIV+) individuals to routine HIV clinic services, where universal ART (irrespective of CD4 count) is offered, with re-visits to support linkage to care. The overall goal is to reduce population-level adult HIV incidence, through achieving high HIV testing and treatment coverage.
The second annual round was June 2015-October 2016. Included in analysis are all individuals aged ≥15 years who consented to participate, with extrapolation to the total population. Our three main outcomes are (1) knowledge of HIV+ status (2) ART coverage, by the end of Round 2 (R2) and compared with the start of R2, and (3) retention on ART on the day of consenting to participate in R2. We used \"time-to-event\" methods to estimate the median time to start ART after referral to care. CHiPs visited 45,631 households during R2, ~98% of the estimated total across the four communities, and for 94% (43,022/45,631) consent was given for all household members to be listed on the CHiPs' electronic register; 120,272 individuals aged ≥15 years were listed, among whom 64% of men (37,265/57,901) and 86% (53,516/62,371) of women consented to participate in R2. We estimated there were 6,521 HIV+ men and 10,690 HIV+ women in the total population of visited households; and that ~80% and ~90% of HIV+ men and women respectively knew their HIV+ status by the end of R2, fairly similar across age groups but lower among those who did not participate in Round 1 (R1). Among those who knew their HIV+ status, ~80% of both men and women were on ART by the end of R2, close to 90% among men aged ≥45 and women aged ≥35 years, but lower among younger adults, those who were resident in R1 but did not participate in R1, and those who were newly resident in the area of the community in which they were living in R2. Overall ART coverage was ~65% among HIV+ men and ~75% among HIV+ women, compared with the cumulative 90-90 target of 81%. Among those who reported ever taking ART, 93% of men and 95% of women self-reported they were on ART and missed 0 pills in the last 3 days. The median time to start ART after referral to care was ~6 months in R2, similar across the age range 25-54 years, compared with ~9.5 months in R1. The two main limitations to our findings were that a comparison with control-arm communities cannot be made until the end of the study; and that to extrapolate to the total population, assumptions were required about individuals who were resident, but did not participate, in R2.
Overall coverage against the 90-90 targets was high after two years of intervention, but was lower among men, individuals aged 18-34 years, and those who did not participate in R1. Our findings reflect the relative difficulties for CHiPs to contact men at home, compared with women, and that it is challenging to reach high levels of testing and treatment coverage in communities with substantial mobility and in-migration. The shortened time to start ART after referral to care in R2, compared with R1, was likely attributable to multiple factors including an increased focus of the CHiPs on linkage to care; increasing community acceptance and understanding of the CHiPs, and of ART and UTT, with time; increased coordination with the clinics to facilitate linkage; and clinic improvements.
Journal Article