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1.
Res Sq ; 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38405783

RESUMO

Background: Anticipated, internal, and enacted stigma are major barriers to TB care engagement, and directly impact patient well-being. Unfortunately, targeted stigma interventions are lacking. We aimed to co-develop a person-centred stigma intervention with TB-affected community members and health workers in South Africa. Methods: Using a community-based participatory research approach, we conducted ten group discussions with people diagnosed with TB (past or present), caregivers, and health workers (total n=87) in Khayelitsha, Cape Town. Group discussions were facilitated by TB survivors. Discussion guides explored experiences and drivers of stigma and used human-centred design principles to co-develop solutions. Recordings were transcribed, coded, thematically analysed and then further interpreted using the socio-ecological model. Results: Intervention components across socio-ecological levels shared common behaviour change strategies, namely education, empowerment, engagement, and innovation. At the individual level, participants recommended counselling to improve TB knowledge and provide ongoing support. TB survivors can guide messaging to nurture stigma resilience by highlighting that TB can affect anyone and is curable, and provide lived experiences of TB to decrease internal stigma. At the interpersonal level, support clubs and family-centred counselling were suggested to dispel TB-related myths and foster support. At the institutional level, health worker stigma reduction training informed by TB survivor perspectives was recommended. Consideration of how integration of TB/HIV care services may exacerbate TB/HIV intersectional stigma and ideas for restructured service delivery models were suggested to decrease anticipated and enacted stigma. At the community level, participants recommended awareness-raising events led by TB survivors, including TB information in school curricula. At the policy level, solutions focused on reducing the visibility generated by a TB diagnosis and resultant stigma in health facilities and shifting tasks to community health workers. Conclusions: Decreasing TB stigma requires a multi-level approach. Co-developing a person-centred intervention with affected communities is feasible and generates stigma intervention components that are directed and implementable. Such community-informed intervention components should be prioritised by TB programs, including integrated TB/HIV care services.

2.
Res Sq ; 2023 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-38168425

RESUMO

Background: Though TB-related stigma is a recognized barrier to care, interventions are lacking and gaps remain in understanding the drivers and experiences of TB-related stigma. We undertook community-based mixed methods stigma assessments to inform stigma intervention design. Methods: We adapted the Stop TB Partnership stigma assessment tool, and trained three peer research associates (PRAs; two TB survivors, one community health worker) to conduct surveys with people with TB (PWTB, n=93) and caregivers of children with TB (n=24) at peri-urban and rural clinic sites in Khayelitsha, Western Cape, and Hammanskraal, Gauteng Province, South Africa. We descriptively analyzed responses for each stigma experience (anticipated, internal, and enacted), calculated stigma scores, and undertook generalized linear regression analysis. We further conducted 25 in-depth interviews with PWTB (n=22) and caregivers TB (n=3). Using inductive thematic analysis, we performed open coding to identify emergent themes, and selective coding to identify relevant quotes. Themes were organised using the CARD (Constraints, Actions, Risks and Desires) framework. Results: Surveys revealed at least one-third of PWTB and one-quarter of caregivers report experiences of anticipated, internal, and/or enacted stigma, which affected engagement throughout the care cascade. Participants in rural locations (compared to peri-urban) reported higher anticipated, internal, and enacted stigma (ß-coefficient 0.72, 0.71, and 0.74). Interview participants described how stigma experiences, including HIV intersectional stigma, act individually and in concert as key constraints to impede care, and underpins failure to disclose a TB diagnosis, isolation, and exclusion. Stigma resilience arose through understanding that TB can affect anyone and should not diminish self-worth. Risks of stigma, driven by fears related to disease severity and infectiousness, led to care disengagement and impaired psychological wellbeing. Participants desired counselling, identifying a specific role for TB survivors as peer counsellors, and community education. Conclusions: Stigma is highly prevalent and negatively impacts TB care and the well-being of PWTB, warranting its assessment as a primary outcome indicator rather than intermediary contributor to poor cascade outcomes. Multicomponent stigma interventions are needed, including counselling for PWTB and education for health workers and communities. Such interventions must incorporate contextual differences based on gender or setting, and use survivor-guided messaging to foster stigma resilience.

3.
PLOS Glob Public Health ; 2(10): e0000989, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36962638

RESUMO

Stigma is a critical barrier for TB care delivery; yet data on stigma reduction interventions is limited. This review maps the available literature on TB stigma reduction interventions, using the Health Stigma and Discrimination framework and an implementation analysis to identify research gaps and inform intervention design. Using search terms for TB and stigma, we systematically searched PubMed, EMBASE and Web of Science. Two independent reviewers screened all abstracts, full-texts, extracted data, conducted a quality assessment, and assessed implementation. Results were categorized by socio-ecological level, then sub-categorized by the stigma driver or manifestation targeted. After screening 1865 articles, we extracted data from nine. Three studies were implemented at the individual and interpersonal level using a combination of TB clubs and interpersonal support to target internal and anticipated stigma among persons with TB. Two studies were implemented at the interpersonal level using counselling or a video based informational tool delivered to households to reduce stigma drivers and manifestations. Three studies were implemented at the organizational level, targeting drivers of stigma among healthcare workers (HW) and enacted stigma among HWs. One study was implemented at the community level using an educational campaign for community members. Stakeholder consultation emphasized the importance of policy level interventions and education on the universality of risk to destigmatize TB. Review findings suggest that internal and anticipated TB stigma may be addressed effectively with interventions targeted towards individuals using counselling or support groups. In contrast, enacted TB stigma may be better addressed with information-based interventions implemented at the organizational or community level. Policy level interventions were absent but identified as critical by stakeholders. Implementation barriers included the lack of high-quality training and integration with mental health services. Three key gaps must be addressed in future research: consistent stigma definitions, standardized stigma measurement, and measurement of implementation outcomes.

4.
BMJ Evid Based Med ; 25(6): 193-198, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-31292208

RESUMO

Developing a clinical practice guideline (CPG) is expensive and time-consuming and therefore often unrealistic in settings with limited funding or resources. Although CPGs form the cornerstone of providing synthesised, systematic, evidence-based guidance to patients, healthcare practitioners and managers, there is no added benefit in developing new CPGs when there are accessible, good-quality, up-to-date CPGs available that can be adapted to fit local needs. Different approaches to CPG development have been proposed, including adopting, adapting or contextualising existing high-quality CPGs to make recommendations relevant to local contexts. These approaches are attractive where technical and financial resources are limited and high-quality guidance already exists. However, few examples exist to showcase such alternative approaches to CPG development. The South African Guidelines Excellence project held a workshop in 2017 to provide an opportunity for dialogue regarding different approaches to guideline development with key examples and case studies from the South African setting. Four CPGs represented the topics: mental health, health promotion, chronic musculoskeletal pain and prehospital emergency care. Each CPG used a different approach, however, using transparent, reportable methods. They included advisory groups with representation from content experts, CPG users and methodologists. They assessed CPGs and systematic reviews for adopting or adapting. Each team considered local context issues through qualitative research or stakeholder engagement. Lessons learnt include that South Africa needs fit-for-purpose guidelines and that existing appropriate, high-quality guidelines must be taken into account. Approaches for adapting guidelines are not clear globally and there are lessons to be learnt from existing descriptions of approaches from South Africa.


Assuntos
Atenção à Saúde , Humanos , Pesquisa Qualitativa , África do Sul
5.
Eur Phys J C Part Fields ; 78(5): 351, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30996663

RESUMO

A small-scale, two-phase (liquid/gas) xenon time projection chamber (Xurich II) was designed, constructed and is under operation at the University of Zürich. Its main purpose is to investigate the microphysics of particle interactions in liquid xenon at energies below 50 keV, which are relevant for rare event searches using xenon as target material. Here we describe in detail the detector, its associated infrastructure, and the signal identification algorithm developed for processing and analysing the data. We present the first characterisation of the new instrument with calibration data from an internal 83 m Kr source. The zero-field light yield is 15.0 and 14.0 photoelectrons/keV at 9.4 and 32.1 keV, respectively, and the corresponding values at an electron drift field of 1 kV/cm are 10.8 and 7.9 photoelectrons/keV. The charge yields at these energies are 28 and 31 electrons/keV, with the proportional scintillation yield of 24 photoelectrons per one electron extracted into the gas phase, and an electron lifetime of 200  µ s. The relative energy resolution, σ / E , is 11.9 and 5.8% at 9.4 and 32.1 keV, respectively using a linear combination of the scintillation and ionisation signals. We conclude with measurements of the electron drift velocity at various electric fields, and compare these to literature values.

6.
Anal Chem ; 79(3): 870-8, 2007 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-17263312

RESUMO

A 16-channel microfluidic chip with an integrated contact conductivity sensor array is presented. The microfluidic network consisted of 16 separation channels that were hot-embossed into polycarbonate (PC) using a high-precision micromilled metal master. All channels were 40 microm deep and 60 microm wide with an effective separation length of 40 mm. A gold (Au) sensor array was lithographically patterned onto a PC cover plate and assembled to the fluidic chip via thermal bonding in such a way that a pair of Au microelectrodes (60 microm wide with a 5 microm spacing) was incorporated into each of the 16 channels and served as independent contact conductivity detectors. The spacing between the corresponding fluidic reservoirs for each separation channel was set to 9 mm, which allowed for loading samples and buffers to all 40 reservoirs situated on the microchip in only five pipetting steps using an 8-channel pipettor. A printed circuit board (PCB) with platinum (Pt) wires was used to distribute the electrophoresis high-voltage to all reservoirs situated on the fluidic chip. Another PCB was used for collecting the conductivity signals from the patterned Au microelectrodes. The device performance was evaluated using microchip capillary zone electrophoresis (mu-CZE) of amino acid, peptide, and protein mixtures as well as oligonucleotides that were separated via microchip capillary electrochromatography (mu-CEC). The separations were performed with an electric field (E) of 90 V/cm and were completed in less than 4 min in all cases. The conductivity detection was carried out using a bipolar pulse voltage waveform with a pulse amplitude of +/-0.6 V and a frequency of 6.0 kHz. The conductivity sensor array concentration limit of detection (SNR = 3) was determined to be 7.1 microM for alanine. The separation efficiency was found to be 6.4 x 10(4), 2.0 x 10(3), 4.8 x 10(3), and 3.4 x 10(2) plates for the mu-CEC of the oligonucleotides and mu-CZE of the amino acids, peptides, and proteins, respectively, with an average channel-to-channel migration time reproducibility of 2.8%. The average resolution obtained for mu-CEC of the oligonucleotides and mu-CZE of the amino acids, peptides, and proteins was 4.6, 1.0, 0.9, and 1.0, respectively. To the best of our knowledge, this report is the first to describe a multichannel microchip electrophoresis device with integrated contact conductivity sensor array.


Assuntos
Condutividade Elétrica , Eletroforese em Microchip/instrumentação , Técnicas Analíticas Microfluídicas/instrumentação , Cimento de Policarboxilato , Aminoácidos/isolamento & purificação , Eletrodos , Desenho de Equipamento , Oligonucleotídeos/isolamento & purificação , Peptídeos/isolamento & purificação , Proteínas/isolamento & purificação
7.
Immunity ; 21(6): 831-42, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15589171

RESUMO

GM-CSF promotes homeostasis of myeloid cells. We report that GM-CSF upregulates mRNA and protein production of the soluble form of membrane bound VEGF receptor-1 (sVEGFR-1) in human monocytes. This sVEGFR-1 was biologically active, as cell-free supernatants from GM-CSF-stimulated monocytes blocked detection of endogenously expressed VEGF and inhibited endothelial cell migration and tube formation, even in the presence of exogenous rhVEGF. VEGF activity was recovered by neutralizing sVEGFR-1. To determine whether these events were important in vivo, Matrigel plugs were incubated with rhVEGF, rhGM-CSF, or rhGM-CSF/rhVEGF and injected into mice. Plugs containing GM-CSF or GM-CSF/VEGF had less endothelial cell invasion than plugs containing rhVEGF and were similar to plugs incubated with PBS alone. Neutralizing antibodies specific for sVEGFR-1 injected in these plugs reversed the effects of GM-CSF or GM-CSF/VEGF, while an isogenic antibody did not. Thus, GM-CSF and monocytes play a vital role in angiogenesis through the regulation of VEGF and sVEGFR-1.


Assuntos
Inibidores da Angiogênese/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Neovascularização Fisiológica/efeitos dos fármacos , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Animais , Membrana Celular/metabolismo , Células Cultivadas , Colágeno/metabolismo , Meios de Cultivo Condicionados/química , Combinação de Medicamentos , Células Endoteliais/citologia , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Janus Quinase 2 , Laminina/metabolismo , Camundongos , Testes de Neutralização , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Tirosina Quinases/metabolismo , Proteoglicanas/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , RNA Mensageiro/genética , Transdução de Sinais , Solubilidade , Fator A de Crescimento do Endotélio Vascular/análise , Fator A de Crescimento do Endotélio Vascular/farmacologia , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/genética
8.
J Immunol ; 171(5): 2637-43, 2003 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-12928417

RESUMO

The impact of the immune response in malignancy is poorly understood. While immune cells can destroy transformed cells, the targeting and accumulation of monocytes and macrophages at tumor sites may promote tumor metastases. The growth factor M-CSF is important in promoting monocyte survival. Since M-CSF(-/-) mice are protected against tumor metastases, we hypothesized that M-CSF induced monocytes to produce angiogenic factors that facilitate metastases. In this study we demonstrate that recombinant human M-CSF induces freshly isolated normal human monocytes to produce and release the growth factor vascular endothelial growth factor (VEGF) in a dose-dependent manner, which peaked at 5 days in culture. VEGF released by these monocytes is biologically active, as cell-free supernatants from these M-CSF-stimulated monocytes induced tube formation in HUVEC. Network formation by these HUVECs after treatment with supernatants from monocytes stimulated with M-CSF were inhibited by anti-VEGF, but not by the isogenic control, Abs. Collectively, these data support an important role for M-CSF and monocytes in VEGF production and angiogenesis.


Assuntos
Fator Estimulador de Colônias de Macrófagos/fisiologia , Monócitos/metabolismo , Neovascularização Fisiológica/fisiologia , Fator A de Crescimento do Endotélio Vascular/biossíntese , Indutores da Angiogênese/antagonistas & inibidores , Indutores da Angiogênese/metabolismo , Inibidores da Angiogênese/farmacologia , Linhagem Celular , Sistema Livre de Células/fisiologia , Células Cultivadas , Colágeno , Combinação de Medicamentos , Endotélio Vascular/metabolismo , Endotélio Vascular/fisiologia , Ensaio de Imunoadsorção Enzimática/métodos , Humanos , Soros Imunes/farmacologia , Laminina , Fator Estimulador de Colônias de Macrófagos/antagonistas & inibidores , Monócitos/fisiologia , Neovascularização Fisiológica/imunologia , Comunicação Parácrina/fisiologia , Proteoglicanas , Proteínas Recombinantes/farmacologia , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Fator A de Crescimento do Endotélio Vascular/imunologia , Fator A de Crescimento do Endotélio Vascular/farmacologia
9.
J Biol Chem ; 278(15): 12894-902, 2003 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-12566444

RESUMO

In the absence of survival factors, blood monocytes undergo spontaneous apoptosis, which involves the activation of caspase-3. Although nitric oxide can block caspase-3 activation and promote cell survival, it can also induce apoptosis. We hypothesized that nitrosothiols that promote protein S-nitrosylation would reduce caspase-3 activation and cell survival, whereas nitric oxide donors (such as 1-propamine 3-(2-hydroxy-2-nitroso-1-propylhydrazine (PAPA) NONOate and diethylamine (DEA) NONOate) that do not target thiol residues would not. Using human monocytes as a model, we observed that nitrosothiol donors S-nitrosoglutathione and S-nitroso-N-acetylpenicillamine suppressed caspase-9 and caspase-3 activity and DNA fragmentation. In contrast, PAPA or DEA NONOate did not promote monocyte survival events and appeared to inhibit monocyte survival induced by macrophage colony-stimulating factor. The caspase-3-selective inhibitor DEVD-fluoromethyl ketone reversed DNA fragmentation events, and the caspase-9 inhibitor LEHD-fluoromethyl ketone reversed caspase-3 activity in monocytes treated with PAPA or DEA NONOate in the presence of macrophage colony-stimulating factor. These results were not caused by differences in glutathione levels or the kinetics of nitric oxide release. Moreover, S-nitrosoglutathione and S-nitroso-N-acetylpenicillamine directly blocked the activity of recombinant caspase-3, which was reversed by the reducing agent dithiothreitol, whereas PAPA or DEA NONOate did not block the enzymatic activity of caspase-3. These data support the hypothesis that nitrosylation of protein thiol residues by nitric oxide is critical for promoting the survival of human monocytes.


Assuntos
Caspases/sangue , Sobrevivência Celular/efeitos dos fármacos , Monócitos/citologia , Doadores de Óxido Nítrico/farmacologia , Óxido Nítrico/farmacologia , Caspase 3 , Caspase 9 , Fragmentação do DNA/efeitos dos fármacos , Ativação Enzimática , Glutationa/sangue , Humanos , Hidrazinas/farmacologia , Técnicas In Vitro , Cinética , Monócitos/efeitos dos fármacos , Monócitos/enzimologia , Óxidos de Nitrogênio , S-Nitrosoglutationa
10.
Electrophoresis ; 23(21): 3760-8, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12432539

RESUMO

We describe the development of an integrated microelectrophoretic system consisting of a contact conductivity detector mounted on-chip for monitoring the separation of double-stranded (ds) DNA fragments produced via the polymerase chain reaction (PCR) using microcapillary electrochromatography as the separation mode. The separation was carried out in a polymer-based microfluidic device, hot-embossed into poly(methylmethacrylate) (PMMA), whose walls were functionalized to produce a C(18)-terminated surface to act as the stationary phase (open channel format). The carrier electrolyte contained the ion-pairing agent, triethylammonium acetate (TEAA) to allow the separation to be carried out using reverse-phase ion-pair capillary electrochromatography (RP-IPCEC). The microelectrophoretic separations were investigated utilizing various solvent strengths (acetonitrile/water) with 25 mM TEAA to observe the effects on the separation efficiency as well as the chromatographic development time and detector performance. The field strength significantly affected the quality of the separation, with no separation observed at 333 V/cm for a low mass dsDNA sizing ladder, but baseline separation achieved using a field strength of 67 V/cm. It was observed that the solvent strength affected the retention behavior of the polyanionic molecules as well as the electroosmotic mobility. Higher acetonitrile compositions in the run buffer resulted in reduced plate numbers, which produced lower chromatographic resolution. The use of conductivity detection allowed mass detection sensitivities in the range of 10(-21) mol with a separation efficiency of 10(4) plates and the performance of the detector independent of the acetonitrile content used in the carrier electrolyte.


Assuntos
DNA/isolamento & purificação , Eletroforese Capilar , Reação em Cadeia da Polimerase , Acetonitrilas , Cromatografia , Condutometria , DNA/análise , Indicadores e Reagentes , Microquímica/instrumentação , Polimetil Metacrilato , Sensibilidade e Especificidade , Solventes
11.
Anal Chem ; 74(10): 2407-15, 2002 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-12038768

RESUMO

An on-column contact conductivity detector was developed for the analysis of various mono- and polyanionic compounds separated by electrophoresis chips fabricated in poly(methyl methacrylate) (PMMA) using hot embossing techniques from Ni electroforms. The detector consisted of a pair of Pt wires (127 microm diameter) with an end-to-end spacing of approximately 20 microm and situated within the fluidic channel. The waveform applied to the electrode pair was a bipolar pulse with a frequency of 5.0 kHz and was used to reduce the charging current from measurement so that the current recorded at the end of one pulse is more representative of the solution conductivity. Using the detector, separations of amino acids, peptides, proteins, and oligonucleotides were demonstrated. For the amino acids and peptides, free-solution zone electrophoresis was performed. A calibration plot for the amino acid alanine was found to be linear from approximately 10 to 100 nM in a carrier electrolyte consisting of 10 mM triethylamonium acetate. The concentration detection limit was found to be 8.0 nM, with the corresponding mass detection limit equal to 3.4 amol (injection volume = 425 pL). The protein separations with conductivity detection were performed using MEKC, in which the carrier electrolyte contained the anionic surfactant sodium dodecyl sulfate (SDS) above its cmc. Near baseline resolution was achieved in the PMMA microchip for a solution containing 8 different proteins. In the case of the DNA fragments, capillary electrochromatography was used with a C18-modified PMMA chip and a carrier electrolyte containing an ion-pairing agent.


Assuntos
Condutividade Elétrica , Eletroforese/instrumentação , Polimetil Metacrilato , Aminoácidos/análise , Ânions/análise , Calibragem , Eletroforese/métodos , Microquímica/instrumentação , Miniaturização , Oligonucleotídeos/análise , Peptídeos/análise , Proteínas/análise
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