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Serological assays for SARS-CoV-2 infection are now widely available for use in diagnostic laboratories. Limited data are available on the performance characteristics in different settings, and at time periods remote from the initial infection. Validation of the Abbott (Architect SARS-CoV-2 IgG), DiaSorin (Liaison SARS-CoV-2 S1/S2 IgG) and Roche (Cobas Elecsys Anti-SARS-CoV-2) assays was undertaken utilising 217 serum samples from 131 participants up to 7 months following COVID-19 infection. The Abbott and DiaSorin assays were implemented into routine laboratory workflow, with outcomes reported for 2764 clinical specimens. Sensitivity and specificity were concordant with the range reported by the manufacturers for all assays. Sensitivity across the convalescent period was highest for the Roche at 95.2-100% (95% CI 81.0-100%), then the DiaSorin at 88.1-100% (95% CI 76.0-100%), followed by the Abbott 68.2-100% (95% CI 53.4-100%). Sensitivity of the Abbott assay fell from approximately 5 months; on this assay paired serum samples for 45 participants showed a significant drop in the signal-to-cut-off ratio and 10 sero-reversion events. When used in clinical practice, all samples testing positive by both DiaSorin and Abbott assays were confirmed as true positive results. In this low prevalence setting, despite high laboratory specificity, the positive predictive value of a single positive assay was low. Comprehensive validation of serological assays is necessary to determine the optimal assay for each diagnostic setting. In this low prevalence setting we found implementation of two assays with different antibody targets maximised sensitivity and specificity, with confirmatory testing necessary for any sample which was positive in only one assay.
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Anticuerpos Antivirales/análisis , Prueba Serológica para COVID-19/métodos , COVID-19/diagnóstico , Anticuerpos Antivirales/sangre , Humanos , Laboratorios , Estudios Longitudinales , SARS-CoV-2 , Sensibilidad y EspecificidadRESUMEN
This discussion paper addresses the safety of HIV cure studies, particularly those involving stopping antiretroviral therapy, known as an analytic treatment interruption (ATI) in the context of the SARS-CoV-2 pandemic. More than 30 studies listed on ClinicalTrials.gov include an ATI and many others were planned to begin over the next 12 months but most were halted due to the COVID-19 pandemic. We consider the ethics, risks and practical considerations to be taken into account before re-opening HIV cure clinical trials, noting the specific risks of ATI in the context of circulating SARS-CoV-2.
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Health policy and systems research (HPSR) guides health system reforms and is essential for South Africa (SA)'s progress towards universal coverage of high-quality healthcare. For HPSR evidence to inform and strengthen health systems, it needs to flow efficiently between evidence producers, evidence synthesisers, evidence processers and disseminators and evidence implementors in an evidence ecosystem. A substantial body of evidence for health systems strengthening is generated in SA, and this informs national and international health system guidelines and guidance. In this manuscript, in celebration of the 50th anniversary of the SA Medical Research Council, we apply an evidence ecosystem lens to the SA health system, and discuss its current functioning in support of the achievement of a high-quality health system that is able to achieve universal health coverage. We use three case studies to describe successes, challenges and gaps in the functioning of the evidence ecosystem. The first case study focuses on using evidence to strengthen health-system governance and support for community health worker programmes. The second case focuses on managing the growing epidemic of drug-resistant tuberculosis, while the third case focuses on social protection, the child support grant and its impact on health. SA scientists are part of global initiatives to strengthen the health-systems evidence ecosystem, specifically through pioneering methods to synthesise evidence and produce evidence-informed guidelines to facilitate evidence use in health-system decision-making. SA institutes of health policy analysis facilitate involvement of evidence producers and synthesisers in the national health system policy-making process. A future priority is to further strengthen national initiatives to translate evidence into policy and practice and to sustain capacity for continuous technical support to health-systems policy development and implementation.
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Atención a la Salud/organización & administración , Práctica Clínica Basada en la Evidencia , Política de Salud , Cobertura Universal del Seguro de Salud , Niño , Agentes Comunitarios de Salud , Epidemias , Financiación Gubernamental , Reforma de la Atención de Salud , Humanos , Estudios de Casos Organizacionales , Política Pública , Sudáfrica , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Tuberculosis Resistente a Múltiples Medicamentos/terapiaRESUMEN
There is a plethora of calcium phosphate (CaP) scaffolds used as synthetic substitutes to bone grafts. The scaffold performance is often evaluated from the quantity of bone formed within or in direct contact with the scaffold. Micro-computed tomography (µCT) allows three-dimensional evaluation of bone formation inside scaffolds. However, the almost identical x-ray attenuation of CaP and bone obtrude the separation of these phases in µCT images. Commonly, segmentation of bone in µCT images is based on gray scale intensity, with manually determined global thresholds. However, image analysis methods, and methods for manual thresholding in particular, lack standardization and may consequently suffer from subjectivity. The aim of the present study was to provide a methodological framework for addressing these issues. Bone formation in two types of CaP scaffold architectures (foamed and robocast), obtained from a larger animal study (a 12 week canine animal model) was evaluated by µCT. In addition, cross-sectional scanning electron microscopy (SEM) images were acquired as references to determine thresholds and to validate the result. µCT datasets were registered to the corresponding SEM reference. Global thresholds were then determined by quantitatively correlating the different area fractions in the µCT image, towards the area fractions in the corresponding SEM image. For comparison, area fractions were also quantified using global thresholds determined manually by two different approaches. In the validation the manually determined thresholds resulted in large average errors in area fraction (up to 17%), whereas for the evaluation using SEM references, the errors were estimated to be less than 3%. Furthermore, it was found that basing the thresholds on one single SEM reference gave lower errors than determining them manually. This study provides an objective, robust and less error prone method to determine global thresholds for the evaluation of bone formation in CaP scaffolds.
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Fosfatos de Calcio/química , Microscopía Electrónica de Rastreo/métodos , Osteogénesis , Andamios del Tejido/química , Microtomografía por Rayos X/métodos , Animales , Perros , Interpretación de Imagen Radiográfica Asistida por ComputadorRESUMEN
Arteries can adapt to sustained changes in blood pressure and flow, and it is thought that these adaptive processes often begin with an altered smooth muscle cell activity that precedes any detectable changes in the passive wall components. Yet, due to the intrinsic coupling between the active and passive properties of the arterial wall, it has been difficult to delineate the adaptive contributions of active smooth muscle. To address this need, we used a novel experimental-computational approach to quantify adaptive functions of active smooth muscle in arterial rings excised from the proximal descending thoracic aorta of mice and subjected to short-term sustained circumferential stretches while stimulated with various agonists. A new mathematical model of the adaptive processes was derived and fit to data to describe and predict the effects of active tone adaptation. It was found that active tone was maintained when the artery was adapted close to the optimal stretch for maximal active force production, but it was reduced when adapted below the optimal stretch; there was no significant change in passive behavior in either case. Such active adaptations occurred only upon smooth muscle stimulation with phenylephrine, however, not stimulation with KCl or angiotensin II. Numerical simulations using the proposed model suggested further that active tone adaptation in vascular smooth muscle could play a stabilizing role for wall stress in large elastic arteries.
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Adaptación Fisiológica , Aorta Torácica/fisiología , Animales , Simulación por Computador , Técnicas In Vitro , Ratones , Modelos Cardiovasculares , Contracción Muscular/fisiología , Miocitos del Músculo Liso/fisiología , Estrés Mecánico , Soporte de PesoRESUMEN
Latency-reversing agents (LRAs), including histone deacetylase inhibitors (HDACi), are being investigated as a strategy to eliminate latency in HIV-infected patients on suppressive antiretroviral therapy. The effectiveness of LRAs in activating latent infection in HIV strains derived from the central nervous system (CNS) is unknown. Here we show that CNS-derived HIV-1 strains possess polymorphisms within and surrounding the Sp transcription factor motifs in the long terminal repeat (LTR). These polymorphisms result in decreased ability of the transcription factor specificity protein 1 to bind CNS-derived LTRs, reducing the transcriptional activity of CNS-derived viruses. These mutations result in CNS-derived viruses being less responsive to activation by the HDACi panobinostat and romidepsin compared with lymphoid-derived viruses from the same subjects. Our findings suggest that HIV-1 strains residing in the CNS have unique transcriptional regulatory mechanisms, which impact the regulation of latency, the consideration of which is essential for the development of HIV-1 eradication strategies.
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Encéfalo/virología , Infecciones por VIH/virología , VIH-1/fisiología , Inhibidores de Histona Desacetilasas/uso terapéutico , Adulto , Encéfalo/metabolismo , Linfocitos T CD4-Positivos , Sistema Nervioso Central/metabolismo , Estudios de Cohortes , Depsipéptidos/farmacología , Infecciones por VIH/tratamiento farmacológico , VIH-1/genética , Humanos , Ácidos Hidroxámicos/farmacología , Indoles/farmacología , Células Jurkat , Masculino , Persona de Mediana Edad , Panobinostat , Polimorfismo Genético , Secuencias Repetidas Terminales , Activación Transcripcional , Latencia del Virus/efectos de los fármacosAsunto(s)
Infecciones por VIH/microbiología , Infecciones por VIH/patología , Neumonía/microbiología , Neumonía/patología , Tuberculosis Cutánea/microbiología , Tuberculosis Cutánea/patología , Adulto , Antibacterianos/uso terapéutico , Brazo/microbiología , Brazo/patología , Humanos , Masculino , Neumonía/virología , Piel/microbiología , Piel/patología , Tuberculosis Cutánea/tratamiento farmacológico , Tuberculosis Cutánea/virologíaRESUMEN
Recent cases of successful control of human immunodeficiency virus (HIV) by bone marrow transplant in combination with suppressive antiretroviral therapy (ART) and very early initiation of ART have provided proof of concept that HIV infection might now be cured. Current efforts focusing on gene therapy, boosting HIV-specific immunity, reducing inflammation and activation of latency have all been the subject of recent excellent reviews. We now propose an additional avenue of research towards a cure for HIV: targeting HIV apoptosis regulatory pathways. The central enigma of HIV disease is that HIV infection kills most of the CD4 T cells that it infects, but those cells that are spared subsequently become a latent reservoir for HIV against which current medications are ineffective. We propose that if strategies could be devised which would favor the death of all cells which HIV infects, or if all latently infected cells that release HIV would succumb to viral-induced cytotoxicity, then these approaches combined with effective ART to prevent spreading infection, would together result in a cure for HIV. This premise is supported by observations in other viral systems where the relationship between productive infection, apoptosis resistance, and the development of latency or persistence has been established. Therefore we propose that research focused at understanding the mechanisms by which HIV induces apoptosis of infected cells, and ways that some cells escape the pro-apoptotic effects of productive HIV infection are critical to devising novel and rational approaches to cure HIV infection.
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Apoptosis , Infecciones por VIH/terapia , VIH-1/fisiología , Animales , Fármacos Anti-VIH/farmacología , Fármacos Anti-VIH/uso terapéutico , Linfocitos T CD4-Positivos/fisiología , Linfocitos T CD4-Positivos/virología , Terapia Genética , Infecciones por VIH/inmunología , Interacciones Huésped-Patógeno , Humanos , Inmunoterapia , Latencia del VirusRESUMEN
BACKGROUND: Hypercalcemia has been reported in association with a number of malignancies, but it is an unusual manifestation of ovarian cancer. This finding at presentation (possibly aggravated by oral calcium intake) led to discovery of a clear cell carcinoma of the ovary. The implications and pathophysiology of this association are reviewed. CASE REPORT: Following presentation with abdominal symptoms, this premenopausal woman was found to have bilateral adnexal masses and hypercalcemia. Her parathormone-related polypeptide was found to be elevated. After surgery and staging, she received adjuvant carboplatin and paclitaxel (later substituted by docetaxel). She has done well on her long-term follow-up. CONCLUSIONS: This rare paraneoplastic manifestation of ovarian cancer may be associated with long-term survival if discovered at an early stage. In this instance, further benefit may have been obtained from adjuvant platinum-based chemotherapy.
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Chemokine CXCL12 and receptor CXCR4 control multiple steps in primary tumor growth and metastasis in breast cancer and more than 20 other human malignancies. Mechanisms that regulate availability of CXCL12 in tumor microenvironments will substantially impact cancer progression and ongoing efforts to target the CXCL12-CXCR4 pathway for cancer chemotherapy. We used dual luciferase imaging to investigate CXCR7-dependent scavenging of CXCL12 in breast tumors in vivo and quantify effects of CXCR7 on tumor growth and metastasis of a separate population of CXCR4+ breast cancer cells. In a mouse xenograft model of human breast cancer, in vivo imaging showed that malignant cells expressing CXCR7 reduced bioluminescent CXCL12 secreted in the primary tumor microenvironment. Capitalizing on sensitive detection of bioluminescent CXCL12, we also demonstrated that CXCR7+ cells reduced amounts of chemokine released from orthotopic tumors into the circulation. Immunofluorescence staining of human primary breast cancers showed expression of CXCR4 and CXCR7 on malignant cells in ≈30% of cases. In most cases, CXCR4 and CXCR7 predominantly were expressed on separate populations of malignant cells in a tumor. We modeled these cases of human breast cancer by co-implanting tumor xenografts with CXCR4+ breast cancer cells, human mammary fibroblasts secreting CXCL12, and CXCR7+ or control breast cancer cells. Bioluminescence imaging showed that CXCR7+ breast cancer cells enhanced proliferation of CXCR4+ breast cancer cells in orthotopic tumors and spontaneous metastases. Treatment with a small-molecule inhibitor of CXCR7 chemokine limited the growth of CXCR4+ breast cancer cells in tumors that also contained malignant CXCR7+ cells. These studies establish a new in vivo imaging method to quantify chemokine scavenging by CXCR7 in the tumor microenvironment and identify that CXCR7+ cells promote growth and metastasis of CXCR4+ breast cancer cells.
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Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Quimiocina CXCL12/metabolismo , Receptores CXCR4/metabolismo , Receptores CXCR/metabolismo , Animales , Neoplasias de la Mama/genética , Línea Celular Transformada , Membrana Celular/metabolismo , Proliferación Celular , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Ratones , Ratones Endogámicos NOD , Ratones Noqueados , Ratones SCID , Metástasis de la Neoplasia , Receptores CXCR/antagonistas & inhibidores , Receptores CXCR/genética , Receptores CXCR4/genética , Carga Tumoral , Microambiente Tumoral/genéticaAsunto(s)
Educación Médica/métodos , Ética Médica/educación , Relaciones Médico-Paciente/ética , Curriculum , Humanos , IndiaRESUMEN
We previously found an association between faster CD4+ T-cell recovery in HIV-infected patients receiving combination antiretroviral therapy (cART) and interleukin-7 receptor-α (IL-7Rα) haplotype-2 in a predominantly Caucasian cohort. This study aims to determine whether this association was also significant in Africans. Patients were recruited from the Uganda AIDS Rural Treatment Outcomes (UARTO) cohort (n=352). We used survival analysis and linear mixed modelling (LMM) to determine factors associated with CD4 T-cell recovery. Eight IL-7Rα single-nucleotide polymorphisms (SNPs) were genotyped in both Africans and Caucasians (n=57). Soluble (s)IL-7Rα levels were measured by ELISA. In UARTO, IL-7Rα haplotype-2 was associated with slower CD4 T-cell recovery following cART by using survival analysis (P=0.020) and no association was found with LMM (P=0.958). The tagging-SNP for IL-7Rα haplotype-2 (rs6897932) was associated with decreased sIL-7Rα (P<0.001). The haplotypes for the IL-7Rα were significantly different in Africans and Caucasians. Using IL-7Rα genotypes we found slower CD4 T-cell recovery in UARTO patients was still associated with rs6897932 (P=0.009) and rs3194051 was associated with faster CD4 T-cell recovery (P=0.006). Unlike Caucasians, we did not demonstrate a significant association between IL-7Rα haplotype 2 and faster CD4 T-cell recovery in Africans. The IL-7Rα SNPs associated with CD4 T-cell recovery following cART differ in African and Caucasian cohorts.
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Linfocitos T CD4-Positivos/inmunología , Infecciones por VIH/genética , Infecciones por VIH/inmunología , Polimorfismo de Nucleótido Simple , Receptores de Interleucina-7/genética , Adulto , Terapia Antirretroviral Altamente Activa , Población Negra/genética , Recuento de Linfocito CD4 , Linfocitos T CD4-Positivos/metabolismo , Femenino , Frecuencia de los Genes , Estudios de Asociación Genética , Infecciones por VIH/tratamiento farmacológico , Haplotipos , Humanos , Masculino , Pronóstico , Receptores de Interleucina-7/sangre , Análisis de Supervivencia , Población Blanca/genéticaRESUMEN
We developed a real-time PCR to quantify 16S rRNA gene levels in plasma from HIV-infected patients as a marker of microbial translocation. The assay uses shrimp nuclease (SNuc) to eliminate DNA contamination, giving high sensitivity and low variability. The 16S rRNA gene levels measured in plasma from HIV patients correlated significantly with lipopolysaccharide levels.
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Bacteriemia/diagnóstico , Traslocación Bacteriana , Técnicas Bacteriológicas/métodos , Genes de ARNr , Infecciones por VIH/complicaciones , Plasma/microbiología , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , ADN Bacteriano/sangre , Humanos , Lipopolisacáridos/sangre , Plasma/química , ARN Ribosómico 16S/genética , Sensibilidad y Especificidad , Estadística como AsuntoRESUMEN
Berardinelli Seip congenital lipodystrophy (BSCL) is a rare metabolic disorder characterized by severe generalized lipodystrophy, insulin resistance, and dyslipedemia since infancy, and onset of overt diabetes mellitus in adolescence. Here we report a 5-month-old infant with clinical and metabolic manifestations of Berardinelli Seip syndrome including overt diabetes mellitus and stroke, which are very rare at this age.
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SETTING: Better integration of treatment support for people living with tuberculosis (TB) and human immuno-deficiency virus/acquired immune-deficiency syndrome (HIV/AIDS) is a challenge in many settings, and has been identified as a service priority. OBJECTIVE: To determine the impact, compared to directly observed therapy, of a TB treatment intervention modelled on the community antiretroviral treatment (ART) support programme in South Africa. DESIGN: An interrupted time-series design was used, including five intervention clinics and five comparison clinics. Data were collected from January 2005 to March 2008 and analysed using Poisson regression. RESULTS: Between April 2007 and March 2008, a total of 71% of all new TB patients starting treatment at the intervention clinics were placed on the intervention. There were no significant differences in cure or treatment success rates for new TB patients between intervention and comparison clinics. There was a small improvement in smear conversion rates in intervention clinics when compared to comparison clinics. CONCLUSION: The new model does not result in significantly different TB cure and treatment success rates, but does result in small improvements in smear conversion rates for smear-positive TB patients. The model holds potential for the better integration of TB and ART support.
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Antituberculosos/uso terapéutico , Personal de Salud , Cumplimiento de la Medicación , Tuberculosis/tratamiento farmacológico , Adulto , Técnicas Bacteriológicas , Estudios de Casos y Controles , Terapia por Observación Directa , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mycobacterium tuberculosis/aislamiento & purificación , Proyectos Piloto , Evaluación de Programas y Proyectos de Salud , Sudáfrica , Esputo/microbiología , Factores de Tiempo , Resultado del Tratamiento , Tuberculosis/diagnóstico , Adulto JovenRESUMEN
The aims of the study were to assess whether Treponema pallidum-specific IgM may provide a useful marker of infectious syphilis in human immunodeficiency virus (HIV)-infected patients, and to compare the performance of a prototype IgM-rapid point-of-care test (PoCT) with a standard IgM-enzyme immunoassay (EIA). Twenty samples from HIV-infected patients with untreated syphilis (n = 4 primary syphilis, n = 11 secondary and n = 5 early latent) and 51 follow-up samples at three, six or 12 months after treatment were tested for the presence of IgM with the Mercia-EIA (Microgen Bioproducts Ltd, Camberley, UK) and a prototype PoCT (Select Vaccines Ltd, Melbourne, Australia). Although sample numbers were small, IgM detection by EIA appears to be a reliable marker for untreated syphilis in HIV-infected patients with primary (4/4 IgM-positive) or secondary syphilis (10/11 IgM-positive, 1/11 equivocal). After treatment, IgM was no longer detected after three months in the majority of patients (87%) and was either negative or equivocal in all patients after six and 12 months. The overall sensitivity of the IgM-PoCT was 82% and varied with clinical stage, being highest in secondary (10/10 EIA positives) but lower in primary (2/4 EIA positives) and early latent syphilis (2/3 EIA positives). Overall specificity was 95%. Rapid detection of IgM would enable clinicians to distinguish between past-treated and infectious syphilis and allow for diagnosis and treatment in a single visit.
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Anticuerpos Antibacterianos/sangre , Infecciones por VIH/microbiología , VIH-1/aislamiento & purificación , Inmunoglobulina M/sangre , Sistemas de Atención de Punto , Sífilis/diagnóstico , Treponema pallidum/inmunología , Especificidad de Anticuerpos , Infecciones por VIH/virología , Humanos , Técnicas para Inmunoenzimas/métodos , Inmunoglobulina M/inmunología , Valor Predictivo de las Pruebas , Estudios Retrospectivos , Sífilis/inmunología , Sífilis/microbiología , Sífilis/virologíaRESUMEN
We conducted this study to assess the efficacy of intermittent short course therapy in all forms of pediatric tuberculosis using a coordinated approach with Revised National Tuberculosis Control Programme (RNTCP). Sixty five children were treated using RNTCP protocols with some modifications, such as dose adjustments or prolongation of treatment in selected children. Overall response rate was 95%(pulmonary 94% and extra pulmonary 97%). There was one case with possible relapse. With dynamic inputs from both the treating pediatrician and personnel from Directly Observed Treatment Short course (DOTS) centers, we could successfully implement RNTCP protocols in childhood tuberculosis.
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Tuberculosis/tratamiento farmacológico , Adolescente , Niño , Preescolar , Esquema de Medicación , Femenino , Humanos , Lactante , Masculino , Estudios Prospectivos , Resultado del TratamientoRESUMEN
This article is part of a series written for people responsible for making decisions about health policies and programmes and for those who support these decision makers. In this article, we discuss the following three questions: What is evidence? What is the role of research evidence in informing health policy decisions? What is evidence-informed policymaking? Evidence-informed health policymaking is an approach to policy decisions that aims to ensure that decision making is well-informed by the best available research evidence. It is characterised by the systematic and transparent access to, and appraisal of, evidence as an input into the policymaking process.
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Humanos , Política Informada por la Evidencia , Formulación de PolíticasRESUMEN
This article is part of a series written for people responsible for making decisions about health policies and programmes and for those who support these decision makers. In this article, we address ways of organising efforts to support evidence-informed health policymaking. Efforts to link research to action may include a range of activities related to the production of research that is both highly relevant to ? and appropriately synthesised for ? policymakers. Such activities may include a mix of efforts used to link research to action, as well as the evaluation of such efforts. Little is known about how best to organise the range of activity options available and, until recently, there have been relatively few organisations responsible for supporting the use of research evidence in developing health policy. We suggest five questions that can help guide considerations of how to improve organisational arrangements to support the use of research evidence to inform health policy decision making.
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Humanos , Formulación de Políticas , Políticas, Planificación y Administración en Salud/organización & administración , Política Informada por la Evidencia , Uso de la Información Científica en la Toma de Decisiones en SaludRESUMEN
This article is part of a series written for people responsible for making decisions about health policies and programmes and for those who support these decision makers. The reliability of systematic reviews of the effects of health interventions is variable. Consequently, policymakers and others need to assess how much confidence can be placed in such evidence. The use of systematic and transparent processes to determine such decisions can help to prevent the introduction of errors and bias in these judgements. In this article, we suggest five questions that can be considered when deciding how much confidence to place in the findings of a systematic review of the effects of an intervention.