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1.
J Antimicrob Chemother ; 74(10): 3035-3043, 2019 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-31289811

RESUMEN

OBJECTIVES: To evaluate long-term virological failure (VF) and drug resistance among HIV-infected Ugandan children on first-line ART. METHODS: In a multicentre prospective cohort study, viral load (VL) and drug resistance mutations (DRMs) were investigated at baseline and 6 monthly intervals in children (age ≤ 12 years). VF (two consecutive VLs >1000 copies/mL or death after 6 months of ART) was defined as early VF (0-24 months of ART) or late VF (25-48 months of ART). An active regimen was defined as partially active if the genotypic susceptibility score (GSS) was <3. RESULTS: Between 2010 and 2011, 316 children were enrolled. Viral suppression was achieved in 75.8%, 71.5%, 72.6% and 69.2% at 12, 24, 36 and 48 months. VF occurred in 111/286 (38.8%), of which 67.6% was early and 32.4% late VF. Early VF was associated with a partially active regimen at baseline (OR 6.0, 95% CI 1.9-18.5), poor adherence (OR 3.1, 95% CI 1.3-7.4) and immunodeficiency (OR 3.3, 95% CI 1.1-10.2). Late VF was associated with age >3 years (OR 2.5, 95% CI 1.0-6.6) and WHO stage 3/4 (OR 4.2, 95% CI 1.4-13.4). Acquired DRMs were detected in 27.0% before 24 months, versus 14.4% after 24 months (P < 0.001). A total of 92.2% of the children with early VF, versus 56.2% with late VF, had a partially active regimen (P < 0.001). CONCLUSIONS: VF rates were high, occurred predominantly in the first 24 months and appeared to increase again in year four. Risk factors and patterns of early VF/DRMs were different from those of late VF/DRMs. Virological control may improve by close monitoring and prompt switching to second-line therapy in the first 24 months. Late VF may be prevented by early start of ART.


Asunto(s)
Fármacos Anti-VIH/uso terapéutico , Farmacorresistencia Viral/efectos de los fármacos , Infecciones por VIH/tratamiento farmacológico , Población Negra , Preescolar , Femenino , VIH-1/efectos de los fármacos , Humanos , Masculino , Insuficiencia del Tratamiento , Uganda , Carga Viral
2.
BMC Med Inform Decis Mak ; 19(1): 139, 2019 07 22.
Artículo en Inglés | MEDLINE | ID: mdl-31331394

RESUMEN

BACKGROUND: Despite WHO guidelines for testing all suspected cases of malaria before initiating treatment, presumptive malaria treatment remains common practice among some clinicians and in certain low-resource settings the capacity for microscopic testing is limited. This can lead to misdiagnosis, resulting in increased morbidity due to lack of treatment for undetected conditions, increased healthcare costs, and potential for drug resistance. This is particularly an issue as multiple conditions share the similar etiologies to malaria, including brucellosis, a rare, under-detected zoonosis. Linking rapid diagnostic tests (RDTs) and digital test readers for the detection of febrile illnesses can mitigate this risk and improve case management of febrile illness. METHODS: This technical advance study examines Connected Diagnostics, an approach that combines the use of point-of-care RDTs for malaria and brucellosis, digitally interpreted by a rapid diagnostic test reader (Deki Reader) and connected to mobile payment mechanisms to facilitate the diagnosis and treatment of febrile illness in nomadic populations in Samburu County, Kenya. Consenting febrile patients were tested with RDTs and patient diagnosis and risk information were uploaded to a cloud database via the Deki Reader. Patients with positive diagnoses were provided digital vouchers for transportation to the clinic and treatment via their health wallet on their mobile phones. RESULTS: In total, 288 patients were tested during outreach visits, with 9% testing positive for brucellosis and 0.6% testing positive for malaria. All patients, regardless of diagnosis were provided with a mobile health wallet on their cellular phones to facilitate their transport to the clinic, and for patients testing positive for brucellosis or malaria, the wallet funded their treatment. The use of the Deki Reader in addition to quality diagnostics at point of care also facilitated geographic mapping of patient diagnoses in relation to key risk areas for brucellosis transmission. CONCLUSIONS: This study demonstrates that the Connected Dx approach can be effective even when addressing a remote, nomadic population and a rare disease, indicating that this approach to diagnosing, treatment, and payment for healthcare costs is feasible and can be scaled to address more prevalent diseases and conditions in more populous contexts.


Asunto(s)
Brucelosis/diagnóstico , Malaria/diagnóstico , Telemedicina , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Brucelosis/epidemiología , Brucelosis/terapia , Teléfono Celular , Niño , Preescolar , Pruebas Diagnósticas de Rutina/métodos , Estudios de Factibilidad , Femenino , Geografía Médica , Humanos , Lactante , Kenia/epidemiología , Malaria/epidemiología , Masculino , Persona de Mediana Edad , Pruebas en el Punto de Atención , Migrantes , Adulto Joven
3.
J Antimicrob Chemother ; 72(2): 365-371, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27999070

RESUMEN

BACKGROUND: Children have an augmented risk of pretreatment HIV drug resistance (PDR) due to exposure to antiretroviral drugs for the prevention of mother-to-child transmission (PMTCT). Paediatric data are essential to evaluate the effectiveness of the restricted number of paediatric regimens currently available, but these data are scarce. METHODS: We conducted a systematic review of the literature on PDR in children (median age ≤12 years) in sub-Saharan Africa. We separately extracted the proportion of children with PDR for children with and without prior PMTCT exposure, used random-effects meta-analysis to pool proportions and used meta-regression to assess subgroup differences. RESULTS: We included 19 studies representing 2617 children from 13 countries. The pooled PDR prevalence was 42.7% (95% CI 26.2%-59.1%) among PMTCT-exposed children and 12.7% (95% CI 6.7%-18.7%) among PMTCT-unexposed children (P = 0.004). The PDR prevalence in PMTCT-unexposed children increased from 0% in 2004 to 26.8% in 2013 (P = 0.009). NNRTI mutations were detected in 32.4% (95% CI 18.7%-46.1%) of PMTCT-exposed children and in 9.7% (95% CI 4.6%-14.8%) of PMTCT-unexposed children; PI mutations were uncommon (<2.5%). PDR was more common in children aged <3 years compared with children aged ≥3 years [40.9% (95% CI 27.6%-54.3%) versus 17.6% (95% CI 8.9%-26.3%), respectively (P = 0.025)]. CONCLUSIONS: The PDR prevalence in African children is high and rapidly increasing. Even in PMTCT-unexposed children, the most recent reports indicate that PDR is present in up to a third of children starting first-line therapy. Our data underscore the importance of initiating PI-based first-line ART in young children (<3 years of age) and suggest that older children may also benefit from this approach.


Asunto(s)
Farmacorresistencia Viral , Infecciones por VIH/epidemiología , Infecciones por VIH/virología , VIH/efectos de los fármacos , África del Sur del Sahara/epidemiología , Niño , Preescolar , VIH/genética , VIH/aislamiento & purificación , Humanos , Lactante , Recién Nacido , Prevalencia
4.
Nat Med ; 6(9): 1036-42, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10973325

RESUMEN

Recent thymic emigrants can be identified by T cell receptor excision circles (TRECs) formed during T-cell receptor rearrangement. Decreasing numbers of TRECs have been observed with aging and in human immunodeficiency virus (HIV)-1 infected individuals, suggesting thymic impairment. Here, we show that in healthy individuals, declining thymic output will affect the TREC content only when accompanied by naive T-cell division. The rapid decline in TRECs observed during HIV-1 infection and the increase following HAART are better explained not by thymic impairment, but by changes in peripheral T-cell division rates. Our data indicate that TREC content in healthy individuals is only indirectly related to thymic output, and in HIV-1 infection is mainly affected by immune activation.


Asunto(s)
Infecciones por VIH/inmunología , VIH-1/inmunología , Receptores de Antígenos de Linfocitos T/genética , Linfocitos T/inmunología , Timo/inmunología , Fármacos Anti-VIH/uso terapéutico , División Celular , Reordenamiento Génico de Linfocito T , Infecciones por VIH/tratamiento farmacológico , Humanos , Linfocitos T/citología
5.
Bull World Health Organ ; 87(10): 794-8, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19876547

RESUMEN

PROBLEM: A multinational company with operations in several African countries was committed to offer antiretroviral treatment to its employees and their dependants. APPROACH: The Accelerating Access Initiative (AAI), an initiative of six pharmaceutical companies and five United Nations' agencies, offered the possibility of obtaining brand antiretroviral drugs (ARVs) at 10% of the commercial price. PharmAccess, a foundation aimed at removing barriers to AIDS treatment in Africa, helped to establish an HIV policy and treatment guidelines, and a workplace programme was rolled out from September 2001. LOCAL SETTING: Private sector employers in Africa are keen to take more responsibility in HIV prevention and AIDS care. An important hurdle for African employers remains the price and availability of ARVs. RELEVANT CHANGES: The programme encountered various hurdles, among them the need for multiple contracts with multiple companies, complex importation procedures, taxes levied on ARVs, lack of support from pharmaceutical companies in importation and transportation, slow delivery of the drugs, lack of institutional memory in pharmaceutical companies and government policies excluding the company from access to ARVs under the AAI. LESSONS LEARNED: The launch of the AAI enabled this multinational company to offer access to ARVs to its employees and dependants. The private sector should have access to these discounted drugs under the AAI. A network of local AAI offices should be created to assist in logistics of drugs ordering, purchase and clearance. No taxes should be levied on ARVs.


Asunto(s)
Fármacos Anti-VIH/uso terapéutico , Infecciones por VIH/tratamiento farmacológico , Accesibilidad a los Servicios de Salud/estadística & datos numéricos , Necesidades y Demandas de Servicios de Salud/estadística & datos numéricos , Internacionalidad , Evaluación de Programas y Proyectos de Salud , Lugar de Trabajo , África del Sur del Sahara , Fármacos Anti-VIH/economía , Terapia Antirretroviral Altamente Activa , Bases de Datos Factuales , Infecciones por VIH/economía , Accesibilidad a los Servicios de Salud/economía , Necesidades y Demandas de Servicios de Salud/economía , Disparidades en el Estado de Salud , Humanos , Pobreza , Desarrollo de Programa
6.
Ned Tijdschr Geneeskd ; 151(48): 2666-71, 2007 Dec 01.
Artículo en Holandés | MEDLINE | ID: mdl-18179083

RESUMEN

--In recent years, implementation of antiretroviral therapy in developing countries with a high prevalence of HIV-1 has been recognised as a public health priority. Consequently, the availability ofantiretroviral combination therapy for people with HIV is increasing rapidly in sub-Saharan Africa. --HIV treatment programmes are implemented according to the standardised, simplified public health guidelines developed by the World Health Organization (WHO). --However, the implementation of treatment programmes in Africa is hindered by several factors, including the lack of adequate immunological and virological laboratory monitoring, insufficient support for adherence to therapy, vulnerable health care systems and the use of suboptimal drug combinations. --These suboptimal treatment conditions increase the risk that resistant virus strains will emerge that are less susceptible to standard first-line combination therapy, thus threatening the long-term success of the treatment programmes. --The WHO has initiated HIVResNet, an international expert advisory board that has developed a global strategy for surveillance and prevention of antiretroviral drug resistance. --The Dutch initiative known as 'PharmAccess African studies to evaluate resistance' (PASER) is contributing to this strategy by creating a surveillance network in sub-Saharan Africa.


Asunto(s)
Síndrome de Inmunodeficiencia Adquirida/tratamiento farmacológico , Fármacos Anti-VIH/uso terapéutico , Farmacorresistencia Viral , Infecciones por VIH/tratamiento farmacológico , VIH-1/efectos de los fármacos , África , Fármacos Anti-VIH/efectos adversos , Terapia Antirretroviral Altamente Activa , Humanos , Cooperación del Paciente , Factores de Riesgo , Resultado del Tratamiento
7.
Ned Tijdschr Geneeskd ; 151(48): 2680-4, 2007 Dec 01.
Artículo en Holandés | MEDLINE | ID: mdl-18179087

RESUMEN

Long-term substantial development aid has not prevented many African countries from being caught in a vicious circle in health care: the demand for care is high, but the overburdened public supply of low quality care is not aligned with this demand. The majority of Africans therefore pay for health care in cash, an expensive and least solidarity-based option. This article describes an innovative approach whereby supply and demand of health care can be better aligned, health care can be seen as a value chain and health insurance serves as the overarching mechanism. Providing premium subsidies for patients who seek health care through private, collective African health insurance schemes stimulates the demand side. The supply of care improves by investing in medical knowledge, administrative systems and health care infrastructure. This initiative comes from the Health Insurance Fund, a unique collaboration of public and private sectors. In 2006 the Fund received Euro 100 million from the Dutch Ministry of Foreign Affairs to implement insurance programmes in Africa. PharmAccess Foundation is the Fund's implementing partner and presents its first experiences in Africa.


Asunto(s)
Servicios de Salud Comunitaria/economía , Servicios de Salud Comunitaria/organización & administración , Financiación Gubernamental , Seguro de Salud , África , Países en Desarrollo , Gastos en Salud , Humanos , Seguro de Salud/economía , Cooperación Internacional , Países Bajos
8.
HIV Clin Trials ; 7(5): 255-62, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-17162320

RESUMEN

BACKGROUND: The lack of human resources for health is presently recognized as a major factor limiting scale-up of antiretroviral treatment (ART) programs in resourcelimited settings. The mobilization of public and private partners, the decentralization of care, and the training of non-HIV specialist nurses and general practitioners could help increase the number of HIV-infected patients receiving ART. In addition to other forms of training, scheduled teleconferences (TCs) have been organized to support a comprehensive HIV treatment program delivered by a private company's health team. OBJECTIVE: To describe the role of the TC as an additional tool in mentoring a company's health care workers (HCWs). METHOD: For this study, all TC reports were retrospectively reviewed and the questions classified by topic. Participating Heineken physicians evaluated the technical quality and scientific relevance of the TCs through an anonymous survey. RESULTS: From October 2001 to December 2003, 10 HCWs working in 14 operating companies in 5 African countries raised 268 problems during 45 TCs. A total of 79 questions (29%) were asked about antiretroviral (ARV) therapy, 53 (20%) about the diagnosis and treatment of opportunistic infection, 43 (16%) about ARV toxicity, 40 (15%) about care organization and policy, 32 (12%) about laboratory or drug supply, and 21 (8%) about biological parameters. The mean TC attendance rate was 70%. The level of satisfaction among local company physicians was 65% for logistics, 89% for scientific relevance, 84% for applicability of advice, and 85% overall. The most common complaints concerned the poor quality of the telephone connection and language problems for francophone participants. CONCLUSION: Database-supported teleconferencing could be an additional tool to mentor company HCWs in their routine care of HIV-infected workers and family members. The role and costeffectiveness of telemedicine in improving health outcomes should be further studied.


Asunto(s)
Bases de Datos como Asunto/estadística & datos numéricos , Infecciones por VIH , VIH , Encuestas de Atención de la Salud , Instituciones Privadas de Salud/estadística & datos numéricos , Evaluación de Programas y Proyectos de Salud/estadística & datos numéricos , Telecomunicaciones/estadística & datos numéricos , África , Antirretrovirales/efectos adversos , Antirretrovirales/uso terapéutico , Infecciones por VIH/complicaciones , Infecciones por VIH/diagnóstico , Infecciones por VIH/terapia , Instituciones Privadas de Salud/normas , Personal de Salud/educación , Humanos , Evaluación de Programas y Proyectos de Salud/normas , Estudios Retrospectivos , Encuestas y Cuestionarios
9.
Biochim Biophys Acta ; 930(1): 1-9, 1987 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-2887210

RESUMEN

The response of guanylate cyclase to addition of extracellular stimuli is well documented. Here we report for the first time the response of guanylate cyclase to removal of stimuli. Three methods were employed to terminate rapidly a stimulus of folic acid. (1) Addition of a highly active folate deaminase preparation, or (2) 12-fold dilution of the stimulated cell suspension, or (3) addition of an excess concentration of a non-agonistic derivative of folic acid, i.e., 2-deaminofolic acid, which chases the folate agonist from its cell-surface receptors. Accumulation of cGMP terminated instantaneously upon addition of deaminase, but degradation of the synthesized cGMP was not observed until 10-12 s after stimulation. Also in a cGMP phosphodiesterase-lacking 'streamer' mutant an instantaneous termination of further cGMP accumulation was observed upon stimulus removal. This suggests that the termination of cGMP accumulation is due to inactivation of guanylate cyclase instead of a steady state of cGMP synthesis and degradation. Further accumulation of cGMP was approx. 75% reduced upon dilution of a cell suspension after stimulation with both agonists. Stimulation by 300 nM folic acid or by 30 nM N10-methylfolic acid (a more potent agonist) yielded identical results. However, upon addition of deaminofolic acid the accumulation of cGMP continued normally if the cells had been stimulated with N10-methylfolic acid, but only slightly in the case of a folic acid stimulus. The effect of stimulus duration on desensitization was monitored; it was observed that 50% desensitization was induced by stimulation for 1 s, while 4 s was sufficient for maximal desensitization. Short stimuli were observed to elicit high levels of desensitization without much excitation of guanylate cyclase. A desensitization-like process was observed at the level of the folate-binding chemotactic receptors as well. Relationships between the cGMP response data and folic acid receptor kinetics are discussed.


Asunto(s)
Proteínas Portadoras/metabolismo , Dictyostelium/metabolismo , Guanilato Ciclasa/metabolismo , Proteínas Protozoarias , Receptores de Superficie Celular , Aminohidrolasas/farmacología , GMP Cíclico/biosíntesis , Receptores de Folato Anclados a GPI , Ácido Fólico/análogos & derivados , Ácido Fólico/metabolismo , Ácido Fólico/farmacología , Proteínas de Unión al GTP/fisiología , Cinética , Metotrexato/análogos & derivados , Metotrexato/metabolismo , Metotrexato/farmacología , Conformación Proteica
10.
AIDS ; 13(11): 1305-11, 1999 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-10449282

RESUMEN

OBJECTIVE: To assess syncytium-inducing (SI) and non-syncytium-inducing (NSI) frequencies, coreceptor usage and gp120 V3 sequences of HIV-1 isolates from Ethiopian AIDS patients. PATIENTS: Cross-sectional study on 48 hospitalized AIDS patients (CD4 T cells < 200 x 10(6) cell/l) with stage III or IV of the WHO staging system for HIV-1 infection and disease. METHODS: Peripheral blood mononuclear cells (PBMC) from all 48 patients were tested by MT-2 assay to determine SI/NSI phenotypes. Lymphocyte subsets were enumerated using Coulter counting and FACScan analysis. Viral load determination used a nucleic acid sequence-based amplification assay (NASBA). Coreceptor usage of HIV-1 biological clones was measured using U87 CD4/chemokine receptor transfectants and phytohemagglutinin-stimulated PBMC of healthy donors with wild-type CCR5 and homozygous mutation CCR5delta32 (a 32 base-pair deletion in CCR5). Reverse transcriptase polymerase chain reaction sequencing was performed on the third variable region (V3) of the HIV-1 gene gp120. Sequence alignments were done manually; phylogenetic analyses used PHYLIP software packages. RESULTS: SI viruses were detected for 3/48 (6%) AIDS patients only. Lower mean absolute CD4 counts were determined in patients with SI virus compared with NSI (P = 0.04), but no differences in viral load were observed. All patients were found to be infected with HIV-1 subtype C, based on V3 sequencing. NSI biological clones used CCR5 as coreceptor; SI biological clones used CXCR4 and/or CCR5 and/or CCR3. CONCLUSIONS: Ethiopian patients with HIV-1 C-subtype AIDS harbour a remarkably low frequency of SI phenotype viruses. Coreceptor usage of these viruses correlates with their biological phenotypes.


Asunto(s)
Células Gigantes/fisiología , Proteína gp120 de Envoltorio del VIH/genética , Infecciones por VIH/virología , VIH-1/clasificación , Fragmentos de Péptidos/genética , Receptores del VIH/metabolismo , Adulto , Estudios Transversales , ADN Viral/genética , Etiopía , Femenino , Infecciones por VIH/inmunología , VIH-1/genética , VIH-1/metabolismo , VIH-1/fisiología , Humanos , Inmunofenotipificación , Leucocitos Mononucleares/virología , Masculino , Fenotipo , Filogenia , ARN Viral/sangre , Análisis de Secuencia de ADN
11.
AIDS ; 13(3): 381-9, 1999 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-10199229

RESUMEN

OBJECTIVE: To study the association between the clinical axis of the World Health Organization (WHO) staging system of HIV infection and disease and laboratory markers in HIV-infected Ethiopians. DESIGN: Cross-sectional study. METHODS: Clinical manifestations and stage of HIV-positive individuals participating in a cohort study of HIV infection progression, and of HIV-positive patients hospitalized with suspicion of AIDS, were compared to CD4+ T-cell count and viral load. RESULTS: Of the 86 HIV-positive participants of the cohort study, 53 (62%), 16 (19%), 16 (19%), and one (1.2%) were in stage 1, 2, 3 and 4, respectively. Minor weight loss (n = 15) and pulmonary tuberculosis (n = 9) were the most commonly diagnosed conditions among the 38 (44%) symptomatic HIV-positive individuals. Although 23 (27%) HIV-positive participants had CD4+ T-cell counts less than 200 x 10(6)/l, only one was in clinical stage 4. Among 79 hospitalized HIV-positive patients, 15 (19%) and 64 (81%) were in stage 3 and 4, respectively. The majority (83.5%) had CD4+ T-cell counts < 200 x 10(6)/l. Individuals at stage 3 had lower CD4+ T-cell counts and higher viral loads when seen in hospital as compared to cohort participants (P = 0.06 and 0.008, respectively). When grouping the two study populations, the median CD4+ T-cell count decreased (337, 262, 225, 126, and 78 x 10(6)/l, P< 0.01), and the median viral load increased (4.08, 3.89, 4.47, 5.65, and 5.65 log10 copies/ml, P < 0.01), with increasing clinical stage of HIV infection (1, 2, 3 cohort, 3 hospital, and 4, respectively). Median CD4+ T-cell counts were remarkably low in HIV-negative participants (749 x 10(6)/l), and in HIV-positive participants at stage 1 and 2 (337 and 262 x 10(6)/l, respectively). CONCLUSIONS: There was a good correlation between WHO clinical stages and biological markers. CD4+ T-cell counts were low in Ethiopians, particularly during early stages of HIV-1 infection, and preliminary reference values at different stages of HIV-1 infection were determined. In HIV-infected Ethiopians, lymphocyte counts less than 1,000 x 10(6)/l in non-hospitalized individuals, and less than 2,000 x 10(6)/l in hospitalized patients, had high positive predictive value, but low sensitivity, in identifying subjects with low CD4+ T-cell counts (< 200 x 10(6)/l) who would benefit from chemoprophylaxis of opportunistic infections. The on-going longitudinal study will be useful to confirm the prognostic value of the WHO staging system.


Asunto(s)
Infecciones por VIH/clasificación , Infecciones por VIH/fisiopatología , Organización Mundial de la Salud , Biomarcadores , Recuento de Linfocito CD4 , Estudios de Cohortes , Estudios Transversales , Etiopía , Estudios de Evaluación como Asunto , VIH-1/fisiología , Humanos , Valor Predictivo de las Pruebas , Índice de Severidad de la Enfermedad , Carga Viral
12.
Hum Immunol ; 27(2): 80-9, 1990 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-2298611

RESUMEN

Recently we have shown that limiting dilution analysis can be used to detect cytotoxic T-cell precursor frequencies directed against individual HLA class I antigens. Using the same protocol, we have been able to define two subtypes of HLA-A1, which are indistinguishable by conventional typing sera as well as by cell-mediated lympholysis. One-dimensional isoelectric focusing analysis of the variants did not show any overall charge differences. However, family studies indicated that these HLA-A1 subtypes are genetically determined and can be distinguished on the bases of T-cell precursor frequencies in HLA-A1-negative blood donors.


Asunto(s)
Antígeno HLA-A1/clasificación , Células Madre Hematopoyéticas/inmunología , Linfocitos T Citotóxicos/inmunología , Unión Competitiva , Tipificación y Pruebas Cruzadas Sanguíneas/métodos , Pruebas Inmunológicas de Citotoxicidad , Antígeno HLA-A1/genética , Humanos
13.
AIDS Res Hum Retroviruses ; 13(12): 1071-5, 1997 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-9264295

RESUMEN

PIP: HIV-1 variants in different geographic regions have been phylogenetically classified into the genetic subtypes A-I and O on the basis of sequence differences in the V3 regions of their gp120 envelope genes. The existence of all HIV-1 subtypes except subtype I has been confirmed in Africa. This paper describes the distribution of HIV-1 subtypes in Ethiopia. The first Ethiopian AIDS case was reported in 1986 and the AIDS epidemic has now become a rapidly growing problem in Addis Ababa, the capital city. HIV-1 seroprevalence in the city is estimated to be 10-27% among pregnant women, 47-59% among prostitutes, and 7% among blood donors. Preliminary sequence data on a limited number of samples indicated the presence of subtype C in Addis Ababa in 1988. 94 sera collected from prostitutes, pregnant women, and blood donors during 1989-95 were analyzed to assess the distribution of HIV-1 subtypes in Addis Ababa. HIV-1 subtype C was identified in 93 of 94 cases. One case of subtype A virus was identified. Subtype C was also highly abundant also before the 1995 sera collection. Finally, the authors discuss how the Ethiopian subtype C sequences differ slightly from the consensus C sequence.^ieng


Asunto(s)
Infecciones por VIH/virología , VIH-1/clasificación , Secuencia de Aminoácidos , Etiopía/epidemiología , Femenino , Infecciones por VIH/sangre , Infecciones por VIH/epidemiología , VIH-1/genética , VIH-1/aislamiento & purificación , Humanos , Datos de Secuencia Molecular , Filogenia , Embarazo , ARN Viral , Homología de Secuencia de Aminoácido
14.
AIDS Res Hum Retroviruses ; 17(5): 433-41, 2001 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-11282012

RESUMEN

Host factors such as increased beta-chemokine production, HIV-1 coreceptor expression level, and HIV-1 coreceptor polymorphism have been thought to influence susceptibility to HIV-1 infection. To determine the protective role of these factors in Ethiopians who remained HIV-1 uninfected, despite multiple high-risk sexual exposures, we studied 21 Ethiopian women who had been employed as commercial sex workers (CSWs) for five or more years. The HIV-1-resistant CSWs were compared with low-risk age-matched female controls who had a comparable CD4+ cell percentage and mean fluorescence intensity (MFI). Genetic polymorphism in the CCR5, CCR2b, or SDF-1 genes appeared not to be associated with resistance in the Ethiopian CSWs. Expression levels of CCR5 and CXCR4 on naive, memory, and total CD4+ T cells tended to be higher in the resistant CSWs, while the production of beta-chemokines RANTES, MIP-1alpha, and MIP-1beta by phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMCs) was lower compared with low-risk HIV-1 negative controls. In vitro susceptibility of PHA-stimulated PBMCs to primary, CCR5-restricted, Ethiopian HIV-1 isolates was comparable between resistant CSWs and low-risk controls. In vitro susceptibility was positively correlated to CD4+ cell mean fluorescence intensity and negatively correlated to CCR5 expression levels, suggesting that infection of PBMCs was primarily dependent on expression levels of CD4 and that CCR5 expression, above a certain threshold, did not further increase susceptibility. Our results show that coreceptor polymorphism, coreceptor expression levels, beta-chemokine production, and cellular resistance to in vitro HIV-1 infection are not associated with protection in high-risk HIV-1-negative Ethiopian CSWs.


Asunto(s)
Seronegatividad para VIH , VIH-1/inmunología , Trabajo Sexual , Adulto , Recuento de Linfocito CD4 , Quimiocinas CC/metabolismo , Quimiocinas CC/farmacología , Estudios de Cohortes , Susceptibilidad a Enfermedades , Etiopía , Femenino , Citometría de Flujo , Humanos , Técnicas In Vitro , Persona de Mediana Edad , Polimorfismo Genético , Receptores CCR5/genética , Receptores CCR5/metabolismo , Receptores de Citocinas/metabolismo , Factores de Riesgo
15.
AIDS Res Hum Retroviruses ; 16(17): 1909-14, 2000 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-11118076

RESUMEN

Others and we have previously shown that subtype C is the predominant HIV-1 subtype and the major cause of AIDS in Ethiopia. The present study shows that subtype C in Ethiopia has a genetic subcluster, designated C', has not increased in frequency, or spread geographically, over the period 1988 (%C' = 23/53) to 1996-1997 (%C' = 26/50). There is no association of the HIV-1 subtype C or subcluster C' with geographic location, time of sample collection, or risk group in Ethiopia. Of 105 randomly collected samples representing 7 different towns in Ethiopia, all but 2 (1 subtype A from Addis Ababa, 1997 and 1 subtype D from Dessie, 1996) belong to subtype C.


Asunto(s)
Infecciones por VIH/epidemiología , Infecciones por VIH/virología , VIH-1/clasificación , VIH-1/genética , Secuencia de Aminoácidos , Etiopía/epidemiología , Proteína gp120 de Envoltorio del VIH/inmunología , Humanos , Datos de Secuencia Molecular , Fragmentos de Péptidos/inmunología , Filogenia , Análisis de Secuencia de ADN
16.
AIDS Res Hum Retroviruses ; 17(7): 657-61, 2001 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-11375063

RESUMEN

Viruses circulating in Ethiopia during the 1990s cluster with main subtype C, but a significant subcluster, C', was noted in multiple analyses. This subcluster of subtype C(C') was in a fifty-fifty equilibrium with the main subtype C (Abebe et al., AIDS Res Hum Retroviruses 2000;16:1909-1914). To analyze genetic diversification within the subcluster of HIV-1 subtype C designated C' in the course of the epidemic in Ethiopia, we analyzed 165 env gp120 V3 sequences obtained between 1988 and 1999. We observed a highly significant positive correlation between sampling years of individual sequences and their synonymous distances to the reconstructed common ancestor of the HIV-1 subtype C' subcluster. The extrapolation of the regression line of synonymous distances back to the date when no synonymous heterogeneity was present among the Ethiopian HIV-1 C' population allowed us to estimate 1982 (95% CI, 1980-1983) as the year of the onset of HIV-1 C' genetic diversification and expansion in Ethiopia. These results are in agreement with retrospective epidemiological and serological data, which demonstrated the absence of an HIV-1 epidemic in the Ethiopian population before the 1980s.


Asunto(s)
Infecciones por VIH/epidemiología , VIH-1/clasificación , VIH-1/genética , Secuencia de Aminoácidos , Secuencia de Consenso , Etiopía/epidemiología , Variación Genética , Proteína gp120 de Envoltorio del VIH/química , Infecciones por VIH/virología , Humanos , Datos de Secuencia Molecular , Fragmentos de Péptidos/química , Alineación de Secuencia , Factores de Tiempo
17.
Trans R Soc Trop Med Hyg ; 92(4): 401-3, 1998.
Artículo en Inglés | MEDLINE | ID: mdl-9850391

RESUMEN

Sera from 170 factory workers aged 18-45 years enrolled in a pilot study of human immunodeficiency virus 1 (HIV-1) infection in Addis Ababa, Ethiopia, were screened for anti-Toxoplasma immunoglobulin G antibodies by the Sabin-Feldman test (reference standard) and the Eiken latex agglutination test (under evaluation for use in developing countries). Based on the Sabin-Feldman test, the prevalence of anti-Toxoplasma antibodies was 80.0% (95% confidence interval 73.9-86.1%). The sensitivity and specificity of the Eiken latex agglutination test were 96.3% and 97.1%, respectively, showing its validity for the detection of anti-Toxoplasma antibodies. The prevalence of antibodies did not differ between individuals infected and uninfected with HIV-1 (74.2% versus 83.3%, P > 0.05). However, antibody titres were higher in HIV-infected persons than in those who were uninfected (P < 0.001). Based on these findings, we expect that toxoplasmic encephalitis will be a common opportunistic infection among HIV-infected Ethiopians, and chemoprophylaxis with co-trimoxazole may be beneficial to those with low CD4+ T cell counts. The prognostic significance of high titres of anti-Toxoplasma antibodies remains to be established among Ethiopian HIV-infected individuals.


Asunto(s)
Anticuerpos Antiprotozoarios/análisis , Seroprevalencia de VIH , Pruebas de Fijación de Látex/normas , Toxoplasma/inmunología , Toxoplasmosis/epidemiología , Adolescente , Adulto , Animales , Etiopía/epidemiología , Femenino , Humanos , Masculino , Proyectos Piloto , Sensibilidad y Especificidad , Salud Suburbana
18.
Semin Cancer Biol ; 2(1): 11-6, 1991 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-1912513

RESUMEN

Expression of HLA class I (-like) genes by two developmental tumour cell lines representing embryonic (Tera-2) and extra-embryonic (Jeg-3) origins is reviewed. The Tera-2 embryonal carcinoma cells are HLA negative but can be induced by gamma interferon to express HLA-A, -B, -C, and apparently -E and G genes. Jeg-3 choriocarcinoma cells constitutively express HLA-G and low levels of a novel HLA-C gene product. The NK sensitivity of the developmental tumour cell types has been assessed and the biochemical characteristics of the surface molecules expressed by the trophoblast derived cells has been further documented. The biological role of these novel HLA molecules in the context of the maternal acceptance of the fetal-semi-allograft is discussed.


Asunto(s)
Coriocarcinoma/inmunología , Antígenos de Histocompatibilidad Clase I/biosíntesis , Teratoma/inmunología , Anticuerpos Monoclonales , Northern Blotting , Línea Celular , Citotoxicidad Inmunológica , Biblioteca de Genes , Antígenos HLA/biosíntesis , Antígenos HLA-A/biosíntesis , Antígenos HLA-B/biosíntesis , Antígenos HLA-C/biosíntesis , Antígenos HLA-G , Humanos , Inmunofenotipificación , Interferón gamma/farmacología , Células Asesinas Naturales/fisiología , Antígenos HLA-E
19.
Differentiation ; 32(3): 192-9, 1986.
Artículo en Inglés | MEDLINE | ID: mdl-2878851

RESUMEN

Recently, we demonstrated the presence of multiple folate-binding sites on the cell surface of Dictyostelium discoideum. These sites were divided into two major classes, with different ligand specificities (A and B). Each major class consists of several interconvertible subtypes. In the present report, the ability of 13 folate analogs to activate both adenylate and guanylate cyclase in pre- as well as postaggregative cells is examined. The patterns of correlation between binding and activation data indicate that guanylate cyclase activation is mediated by the B-sites in both developmental stages (P less than 0.001). In postaggregative cells, adenylate cyclase also seems to be activated by the B-sites (P less than 0.001). In contrast, adenylate cyclase activation in preaggregative cells was well correlated with the specificity of A-sites (P less than 0.01). Remarkably, the potencies of activation were less affected by molecular modifications than the binding affinities were, as suggested by a slope of 0.4 in a plot of K0.5 values of activation vs. binding. This observation argues against the existence of a transduction mechanism in which the response is proportional to receptor occupancy. For the B-receptor, however, the degree of receptor occupancy appears to determine the response. The existence of folic acid antagonists is demonstrated, some of which are specific for either A-sites coupled to adenylate cyclase or for B-sites coupled to guanylate cyclase.


Asunto(s)
Proteínas Portadoras/metabolismo , AMP Cíclico/biosíntesis , GMP Cíclico/biosíntesis , Dictyostelium/metabolismo , Ácido Fólico/farmacología , Receptores de Superficie Celular , Adenilil Ciclasas/metabolismo , Dictyostelium/enzimología , Activación Enzimática , Receptores de Folato Anclados a GPI , Ácido Fólico/análogos & derivados , Antagonistas del Ácido Fólico/análisis , Guanilato Ciclasa/metabolismo , Cinética
20.
Infect Immun ; 61(9): 3642-7, 1993 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-8359887

RESUMEN

The genes for two novel members (designated 85A and 85C) of the Mycobacterium leprae antigen 85 complex family of proteins and the gene for the closely related M. leprae MPT51 protein were isolated. The complete DNA sequence of the M. leprae 85C gene and partial sequences of the 85A and MPT51 genes are presented. As in M. tuberculosis, the M. leprae 85A, 85C, and previously identified 85B component genes are not closely linked on the genome. However, the MPT51 genes of both species localize close to the respective 85A component genes. Like the 85B component, the M. leprae 85A-MPT51 and 85C antigens are recognized by T cells from healthy contacts and leprosy patients.


Asunto(s)
Antígenos Bacterianos/genética , Proteínas Bacterianas/genética , Genes Bacterianos , Mycobacterium leprae/inmunología , Secuencia de Aminoácidos , Antígenos Bacterianos/química , Proteínas Bacterianas/química , Secuencia de Bases , Regulación Bacteriana de la Expresión Génica , Humanos , Datos de Secuencia Molecular , Mycobacterium leprae/genética , Linfocitos T/inmunología
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