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1.
Vaccines (Basel) ; 12(6)2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38932426

RESUMO

Measles and rubella are vaccine-preventable viral diseases and can be prevented by safe, highly effective vaccination with measles- and rubella-containing vaccines. Given the myriad causes of febrile exanthems, laboratory surveillance for both measles and rubella is important to document the incidence of these diseases and to track the progress and maintenance of elimination in near- and post-elimination settings. Diagnostic challenges can hinder effective surveillance and classification challenges can hinder efforts to demonstrate achievement or maintenance of elimination. In this report, we review diagnostic and classification challenges for measles and rubella in near- and post-elimination settings.

2.
J Infect Dis ; 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38592952

RESUMO

The association between granulomas and vaccine-derived rubella virus (VDRV) in people with primary immune deficiencies (PID) has raised concerns about the ability of immunoglobulin (IG) preparations to neutralize VDRVs. We investigated the capacity of IG to neutralize rubella vaccine virus and four VDRV strains. As expected, the rubella vaccine virus itself was potently neutralized by IG preparations; however, the VDRV isolates from patients after intra-host evolution, 2-6 times less so. Diagnosis of immune deficiencies before possible live-virus vaccination is thus of critical importance, while IG replacement therapy can be expected to provide protection from rubella virus infection.


The occurrence of granulomas associated with vaccine derived rubella viruses (VDRV) in people with primary immune deficiencies (PID) challenges immunoglobulin (IG) preparations regarding their rubella neutralizing ability. This study confirmed potent rubella virus neutralization capacity of IG preparations and thus suggests protection of IG-treated PID patients against rubella. The study also highlights the importance of early diagnosis and timely given IG to prevent possible systemic spread of VDRV persisting locally in granulomas.

3.
Emerg Infect Dis ; 28(13): S59-S68, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36502414

RESUMO

The US President's Emergency Plan for AIDS Relief (PEPFAR) supports molecular HIV and tuberculosis diagnostic networks and information management systems in low- and middle-income countries. We describe how national programs leveraged these PEPFAR-supported laboratory resources for SARS-CoV-2 testing during the COVID-19 pandemic. We sent a spreadsheet template consisting of 46 indicators for assessing the use of PEPFAR-supported diagnostic networks for COVID-19 pandemic response activities during April 1, 2020, to March 31, 2021, to 27 PEPFAR-supported countries or regions. A total of 109 PEPFAR-supported centralized HIV viral load and early infant diagnosis laboratories and 138 decentralized HIV and TB sites reported performing SARS-CoV-2 testing in 16 countries. Together, these sites contributed to >3.4 million SARS-CoV-2 tests during the 1-year period. Our findings illustrate that PEPFAR-supported diagnostic networks provided a wide range of resources to respond to emergency COVID-19 diagnostic testing in 16 low- and middle-income countries.


Assuntos
COVID-19 , Infecções por HIV , Humanos , Teste para COVID-19 , Patologia Molecular , Pandemias , SARS-CoV-2 , COVID-19/diagnóstico
4.
Glob Health Sci Pract ; 10(3)2022 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-36332072

RESUMO

INTRODUCTION: Delayed HIV diagnosis in HIV-exposed infants (HEIs) results in missed opportunities for early antiretroviral therapy (ART), causing significant morbidity and mortality. Early infant diagnosis (EID) depends on the availability of accessible and reliable testing services. We explored the acceptability, appropriateness, and feasibility of deploying a targeted community-based point-of-care (POC) EID testing model (i.e., "community POC model") to reach high-risk mother-infant pairs (MIPs) in Lusaka, Zambia. METHODS: We conducted in-depth interviews with a purposive sample of health care workers, study staff, and caregivers in high-risk MIPs at 6 health facilities included in a larger implementation research study evaluating the community POC model. We defined "high-risk MIPs" as mothers who did not receive antenatal testing or an attended delivery or infants who missed EID testing milestones. Interviews were audio-recorded, translated, and transcribed verbatim in English. Content and thematic analysis were done using NVivo 10 software. RESULTS: Health care workers (n=20) and study staff (n=12) who implemented the community POC model noted that the portability and on-screen prompts of the POC platform made it mobile and easy to use, but maintenance and supply chain management were key to field operations. Respondents also felt that the community POC model reached more infants who had never had EID testing, allowing them to find infants with HIV infection and immediately initiate them on ART. Caregivers (n=22) found the community POC model acceptable, provided that privacy could be ensured because the service was convenient and delivered close to home. CONCLUSION: We demonstrate the acceptability, appropriateness, and feasibility of implementing the community POC model in Zambia, while identifying potential challenges related to client privacy and platform field operations. The community POC model may represent a promising strategy to further facilitate active HIV case finding and linkage to ART for children with undiagnosed HIV infection in the community.


Assuntos
Infecções por HIV , Sistemas Automatizados de Assistência Junto ao Leito , Lactente , Criança , Feminino , Humanos , Gravidez , Infecções por HIV/diagnóstico , Infecções por HIV/tratamento farmacológico , Zâmbia , Diagnóstico Precoce , Testes Imediatos
5.
NPJ Microgravity ; 5: 11, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31123701

RESUMO

Mesenchymal stem cells (MSC) rely on their ability to integrate physical and spatial signals at load bearing sites to replace and renew musculoskeletal tissues. Designed to mimic unloading experienced during spaceflight, preclinical unloading and simulated microgravity models show that alteration of gravitational loading limits proliferative activity of stem cells. Emerging evidence indicates that this loss of proliferation may be linked to loss of cellular cytoskeleton and contractility. Low intensity vibration (LIV) is an exercise mimetic that promotes proliferation and differentiation of MSCs by enhancing cell structure. Here, we asked whether application of LIV could restore the reduced proliferative capacity seen in MSCs that are subjected to simulated microgravity. We found that simulated microgravity (sMG) decreased cell proliferation and simultaneously compromised cell structure. These changes included increased nuclear height, disorganized apical F-actin structure, reduced expression, and protein levels of nuclear lamina elements LaminA/C LaminB1 as well as linker of nucleoskeleton and cytoskeleton (LINC) complex elements Sun-2 and Nesprin-2. Application of LIV restored cell proliferation and nuclear proteins LaminA/C and Sun-2. An intact LINC function was required for LIV effect; disabling LINC functionality via co-depletion of Sun-1, and Sun-2 prevented rescue of cell proliferation by LIV. Our findings show that sMG alters nuclear structure and leads to decreased cell proliferation, but does not diminish LINC complex mediated mechanosensitivity, suggesting LIV as a potential candidate to combat sMG-induced proliferation loss.

6.
Pediatr Infect Dis J ; 38(5): 503-507, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30640198

RESUMO

BACKGROUND: The main objective of this study was to determine the frequency and patterns of HIV drug resistance-associated mutations among children under 18 months of age born to HIV-1-positive mothers enrolled in the prevention of mother-to-child transmission services in Haiti. METHODS: Between January 1, 2013 and December 31, 2014, HIV-positive remnant dried blood spots collected from children under 18 months of age for Early Infant Diagnosis at the National Public Health Laboratory were used for HIV-1 genotyping. HIV drug resistance mutations were analyzed using the Stanford Drug Resistance HIVdb program. RESULTS: Of the 3555 dried blood spots collected for Early Infant Diagnosis, 360 (10.1%) were HIV-positive and 355 were available for genotyping. Of these, 304 (85.6%) were successfully genotyped and 217 (71.4%) had ≥1 drug resistance mutation. Mutations conferring resistance to nucleoside reverse transcriptase inhibitor (NRTIs) and non-NRTIs were present in 40.5% (123) and 69.1% (210), respectively. The most frequent mutations were K103N/S (48.0%), M184V (37.5%), G190A/S (15.1%), and Y181C/G/V (14.1%). Predicted drug resistance analysis revealed that 68.8% of the children had high-level resistance to non-NRTIs and 11.5% had intermediate to high-level resistance to abacavir. CONCLUSIONS: This study showed high rates of resistance to NRTIs and non-NRTIs among newly HIV-diagnosed children in Haiti, suggesting that in the era of "Option B+" (initiation of lifelong combination antiretroviral therapy to pregnant women with HIV), the majority of children who acquire HIV infection through mother-to-child transmission of HIV have resistant HIV. These results have led the National HIV Program to revise the pediatric guidelines to include protease inhibitors in first-line regimens for all HIV-positive newborns.


Assuntos
Farmacorresistência Viral , Infecções por HIV/virologia , HIV-1/genética , Transmissão Vertical de Doenças Infecciosas , Feminino , Genótipo , Técnicas de Genotipagem , Infecções por HIV/transmissão , HIV-1/efeitos dos fármacos , HIV-1/isolamento & purificação , Haiti , Humanos , Lactente , Recém-Nascido , Masculino , Mutação de Sentido Incorreto , Gravidez , Prevalência
7.
PLoS One ; 13(9): e0203296, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30192818

RESUMO

INTRODUCTION: Surveillance of HIV drug resistance (HIVDR) is crucial to ensuring the continued success of antiretroviral therapy (ART) programs. With the concern of reduced genotyping sensitivity of HIV on dried blood spots (DBS), DBS for HIVDR surveillance have been limited to ART-naïve populations. To investigate if DBS under certain conditions may also be a feasible sample type for HIVDR testing in ART patients, we piloted nationwide surveys for HIVDR among ART patients using DBS in two African countries with rapid scale-up of ART. METHODS: EDTA-venous blood was collected to prepare DBS from adult and pediatric ART patients receiving treatment during the previous 12-36 months. DBS were stored at ambient temperature for two weeks and then at -80°C until shipment at ambient temperature to the WHO-designated Specialized HIVDR Laboratory at CDC in Atlanta. Viral load (VL) was determined using NucliSENS EasyQ® HIV-1 v2.0 kits; HIVDR genotyping was performed using the ATCC HIV-1 Drug Resistance Genotyping kits. RESULTS: DBS were collected from 1,368 and 1,202 ART patients; 244 and 255 these specimens had VL ≥1,000 copies/mL in Kenya and Tanzania, respectively. The overall genotyping rate of those DBS with VL ≥1,000 copies/mL was 93.0% (95% CI: 89.1%-95.6%) in Kenya and 91.8% (87.7%-94.6%) in Tanzania. The turnaround times for the HIVDR surveys from the time of collecting DBS to completing laboratory testing were 6.5 months and 9.3 months for the Kenya and Tanzania surveys, respectively. CONCLUSIONS: The study demonstrates a favorable outcome of using DBS for nationwide surveillance of HIVDR in ART patients. Our results confirm that DBS collected and stored at ambient temperature for two weeks, and shipped with routine courier services are a reliable sample type for large-scale surveillance of acquired HIVDR.


Assuntos
Teste em Amostras de Sangue Seco/métodos , Farmacorresistência Viral , Infecções por HIV/tratamento farmacológico , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , Adulto , Fármacos Anti-HIV/uso terapêutico , Criança , Estudos Transversais , Farmacorresistência Viral/genética , Monitoramento Epidemiológico , Feminino , Infecções por HIV/epidemiologia , HIV-1/genética , Humanos , Quênia/epidemiologia , Masculino , Tanzânia/epidemiologia , Carga Viral
8.
Clin Infect Dis ; 64(6): 796-803, 2017 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-28200031

RESUMO

The recent Ebola virus outbreak in West Africa clearly demonstrated the critical role of laboratory systems and networks in responding to epidemics. Because of the huge challenges in establishing functional laboratories at all tiers of health systems in developing countries, strengthening specimen referral networks is critical. In this review article, we propose a platform strategy for developing specimen referral networks based on 2 models: centralized and decentralized laboratory specimen referral networks. These models have been shown to be effective in patient management in programs in resource-limited settings. Both models lead to reduced turnaround time and retain flexibility for integrating different specimen types. In Haiti, decentralized specimen referral systems resulted in a 182% increase in patients enrolling in human immunodeficiency virus treatment programs within 6 months. In Uganda, cost savings of up to 62% were observed with a centralized model. A platform strategy will create a network effect that will benefit multiple disease programs.

9.
Tex Dent J ; 134(4): 236-245, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30725552

RESUMO

The Soladey™ toothbrush has a moisture-permeable titanium dioxide (TiO2) resin core in the replacement brush end of a handle activated by light conversion power cells. Purported to have an antibacterial effect and remove more plaque than an ordinary toothbrush, this study was undertaken to establish output measurements of the dry and wet TiO2 core of the toothbrush during typical illumination of the handle, then quantify lipid peroxidation in three distinct lipid-containing solutions, and bactericidal effects in a live bacterial suspension grown from suctioned oral secretions. METHODS: Within a range of illumination of the power cells in the handle, corresponding flow of electrons emitted from dry and wetted TiO2 cores was measured. The claim that an antibacterial effect can be attributed to generation of reactive oxygen-mediated lipid peroxidation of cell membranes was tested by exposing three lipid substrates to the light-activated ionic toothbrush tips for incremental periods of time. Products of lipid peroxidation were quantified using 3 commercially available assays, and bactericidal effects were assessed by scoring colony-forming units. RESULTS: Illumination of the handle generated quantifiable increases in electrons flowing from the wetted TiO2 core. Immersion of the TiO2 core end of illuminated toothbrush handles into lipid substrates showed linear effects of incremental exposure times on products of lipid peroxidation, but no evidence of a bactericidal effect occurring within 15 minutes. CONCLUSIONS: This validates capacity of the wetted current- activated TiO2 core to generate time-dependent lipid peroxides, particularly in the sonicated matrix containing disrupted cell membranes. Finding no time-dependent reduction in colony- forming units and less lipid peroxidation in a suspension of intact cells casts doubt that the ionic toothbrush has an immediate antibacterial effect while brushing teeth. If a toothbrush with a TiO2 core is self-disinfecting between uses, bactericidal effects requiring longer periods of exposure might still confer a hygienic advantage.


Assuntos
Titânio/química , Escovação Dentária/instrumentação , Equipamentos e Provisões Elétricas , Elétrons , Desenho de Equipamento , Humanos , Peroxidação de Lipídeos , Semicondutores , Células-Tronco , Avaliação da Tecnologia Biomédica
10.
AIDS Res Hum Retroviruses ; 33(3): 203-210, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27758117

RESUMO

Early diagnosis of HIV infection in infants and children remains a challenge in resource-limited settings, with approximately half of all HIV-exposed infants receiving virological testing for HIV by the recommended age of 2 months in 2015. To reduce morbidity and mortality among HIV-infected children and close the treatment gap for HIV-infected children, there is an urgent need to evaluate existing programmatic and laboratory practices for early infant diagnosis and introduce strategies to improve identification of HIV-exposed infants and ensure access to systematic, early HIV testing, with early linkage to treatment for HIV-infected infants. This article describes progress made in follow-up of HIV-exposed infants since 2006, including remaining unmet laboratory and programmatic needs, and recommends strategies for improvement, especially those related to the implementation of point-of-care technology for early infant diagnosis.


Assuntos
Infecções por HIV/diagnóstico , Programas de Rastreamento/métodos , Programas de Rastreamento/organização & administração , Sistemas Automatizados de Assistência Junto ao Leito , Diagnóstico Precoce , Humanos , Lactente
11.
MMWR Morb Mortal Wkly Rep ; 65(46): 1285-1290, 2016 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-27880749

RESUMO

Pediatric human immunodeficiency virus (HIV) infection remains an important public health issue in resource-limited settings. In 2015, 1.4 million children aged <15 years were estimated to be living with HIV (including 170,000 infants born in 2015), with the vast majority living in sub-Saharan Africa (1). In 2014, 150,000 children died from HIV-related causes worldwide (2). Access to timely HIV diagnosis and treatment for HIV-infected infants reduces HIV-associated mortality, which is approximately 50% by age 2 years without treatment (3). Since 2011, the annual number of HIV-infected children has declined by 50%. Despite this gain, in 2014, only 42% of HIV-exposed infants received a diagnostic test for HIV (2), and in 2015, only 51% of children living with HIV received antiretroviral therapy (1). Access to services for early infant diagnosis of HIV (which includes access to testing for HIV-exposed infants and clinical diagnosis of HIV-infected infants) is critical for reducing HIV-associated mortality in children aged <15 years. Using data collected from seven countries supported by the U.S. President's Emergency Plan for AIDS Relief (PEPFAR), progress in the provision of HIV testing services for early infant diagnosis was assessed. During 2011-2015, the total number of HIV diagnostic tests performed among HIV-exposed infants within 6 weeks after birth (tests for early infant diagnosis of HIV), as recommended by the World Health Organization (WHO) increased in all seven countries (Cote d'Ivoire, the Democratic Republic of the Congo, Haiti, Malawi, South Africa, Uganda, and Zambia); however, in 2015, the rate of testing for early infant diagnosis among HIV-exposed infants was <50% in five countries. HIV positivity among those tested declined in all seven countries, with three countries (Cote d'Ivoire, the Democratic Republic of the Congo, and Uganda) reporting >50% decline. The most common challenges for access to testing for early infant diagnosis included difficulties in specimen transport, long turnaround time between specimen collection and receipt of results, and limitations in supply chain management. Further reductions in HIV mortality in children can be achieved through continued expansion and improvement of services for early infant diagnosis in PEPFAR-supported countries, including initiatives targeted to reach HIV-exposed infants, ensure access to programs for early infant diagnosis of HIV, and facilitate prompt linkage to treatment for children diagnosed with HIV infection.


Assuntos
Diagnóstico Precoce , Infecções por HIV/diagnóstico , Programas de Rastreamento/estatística & dados numéricos , África Subsaariana , Região do Caribe , Feminino , Infecções por HIV/transmissão , Humanos , Lactente , Transmissão Vertical de Doenças Infecciosas , Gravidez
12.
Dig Dis Sci ; 61(8): 2252-2261, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27074920

RESUMO

BACKGROUND: IL-1ß is a cytokine involved in mediating epithelial barrier dysfunction in the gut. It is known that IL-1ß mediates activation of non-muscle myosin light chain kinase in epithelial cells, but the precise mechanism by which epithelial barrier dysfunction is induced by IL-1ß is not understood. METHODS AND RESULTS: Using a Caco2 cell model, we show that the expression of the tight junction protein, claudin-3, is transcriptionally downregulated by IL-1ß treatment. In addition, after assessing protein and mRNA expression, and protein localization, we show that inhibition of nmMLCK rescues IL-1ß-mediated decrease in claudin-3 expression as well as junction protein redistribution. Using chromatin immunoprecipitation assays, we also show that ß-catenin targeting of the claudin-3 promoter occurs as a consequence of IL-1ß-mediated epithelial barrier dysfunction, and inhibition of nmMLCK interferes with this interaction. CONCLUSIONS: Taken together, these data represent the first line of evidence demonstrating nmMLCK regulation of claudin-3 expression in response to IL-1ß-treated epithelial cells.


Assuntos
Claudina-3/efeitos dos fármacos , Interleucina-1beta/farmacologia , Mucosa Intestinal/diagnóstico por imagem , Permeabilidade/efeitos dos fármacos , RNA Mensageiro/efeitos dos fármacos , Junções Íntimas/efeitos dos fármacos , beta Catenina/efeitos dos fármacos , Azepinas/farmacologia , Células CACO-2 , Imunoprecipitação da Cromatina , Claudina-3/genética , Claudina-3/metabolismo , Inibidores Enzimáticos/farmacologia , Humanos , Imuno-Histoquímica , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Microscopia Confocal , Quinase de Cadeia Leve de Miosina/antagonistas & inibidores , Quinase de Cadeia Leve de Miosina/metabolismo , Naftalenos/farmacologia , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Junções Íntimas/metabolismo , beta Catenina/genética , beta Catenina/metabolismo
13.
Biochem Biophys Res Commun ; 456(1): 190-6, 2015 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-25446122

RESUMO

A key event in the progression of systemic inflammation resulting from severe trauma or shock involves microvascular hyperpermeability, which leads to excessive plasma fluid and proteins accumulating in extravascular space resulting in tissue edema. The precise molecular mechanism of the hyperpermeability response is not completely understood. Protein tyrosine kinase 6 (PTK6, also known as breast tumor kinase BRK) is a non-receptor tyrosine kinase related to Src-family proteins. Although it has also been shown that PTK6 participates in regulating epithelial barrier function, the role of PTK6 in endothelial barrier function has not been reported. In this study, we hypothesized that PTK6 is (1) expressed in vascular endothelial cells, and (2) contributes to vascular endothelial hyperpermeability in response to TNFα. Results showed that PTK6 was detected in mouse endothelial cells at the level of protein and mRNA. In addition, PTK6 knockdown attenuated TNFα induced decrease in endothelial barrier function as measured by electric cell-substrate impedance sensing (ECIS) and in vitro transwell albumin-flux assays. Furthermore, we showed that TNFα treatment of endothelial cells increased active PTK6 association with p120-catenin at endothelial cell-cell junctions. Further analysis using immunocytochemistry and immunoprecipitation demonstrated that PTK6 knockdown attenuated TNFα induced VE-cadherin internalization as well as promoting its association with p120-catenin. Our study demonstrates a novel role of PTK6 in mediating endothelial barrier dysfunction.


Assuntos
Endotélio/patologia , Regulação da Expressão Gênica , Fator de Necrose Tumoral alfa/metabolismo , Quinases da Família src/fisiologia , Animais , Antígenos CD/metabolismo , Caderinas/metabolismo , Cateninas/metabolismo , Comunicação Celular , Membrana Celular/metabolismo , Núcleo Celular/metabolismo , Inflamação/metabolismo , Camundongos , Permeabilidade , Transporte Proteico , Proteínas Tirosina Quinases , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Quinases da Família src/metabolismo , delta Catenina
14.
PLoS One ; 9(10): e109060, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25303690

RESUMO

As more HIV-infected people gain access to antiretroviral therapy (ART), monitoring HIV drug resistance (HIVDR) becomes essential to combat both acquired and transmitted HIVDR. Studies have demonstrated dried blood spots (DBS) are a suitable alternative in HIVDR monitoring using DBS collected on Whatman 903 (W-903). In this study, we sought to evaluate two other commercially available filter papers, Ahlstrom 226 (A-226) and Munktell TFN (M-TFN), for HIVDR genotyping following ambient temperature storage. DBS were prepared from remnant blood specimens collected from 334 ART patients and stored at ambient temperature for a median time of 30 days. HIV-1 viral load was determined using NucliSENS EasyQ® HIV-1 v2.0 RUO test kits prior to genotyping of the protease and reverse transcriptase regions of the HIV-1 pol gene using an in-house assay. Among the DBS tested, 26 specimens had a viral load ≥ 1000 copies/mL in all three types of filter paper and were included in the genotyping analysis. Genotyping efficiencies were similar between DBS collected on W-903 (92.3%), A-226 (88.5%), and M-TFN (92.3%) filter papers (P = 1.00). We identified 50 DR-associated mutations in DBS collected on W-903, 33 in DBS collected on A-226, and 48 in DBS collected on M-TFN, resulting in mutation detection sensitivities of 66.0% for A-226 and 88.0% for M-TFN when compared to W-903. Our data indicate that differences among filter papers may exist at this storage condition and warrant further studies evaluating filter paper type for HIVDR monitoring.


Assuntos
Teste em Amostras de Sangue Seco/métodos , Farmacorresistência Viral , Infecções por HIV/sangue , HIV-1/genética , HIV-1/isolamento & purificação , Filtração/métodos , Genótipo , Infecções por HIV/tratamento farmacológico , Humanos , Dados de Sequência Molecular , Mutação , Temperatura , Carga Viral
15.
Comput Methods Biomech Biomed Engin ; 16(10): 1096-105, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23514117

RESUMO

Neurogenesis has been the subject of active research in recent years. Although the majority of neurons form during the embryonic period, neurogenesis continues in restricted regions of the mammalian brain well into adulthood. In rodent brains, neuronal migration is present in the rostral migratory stream (RMS), connecting the subventricular zone to the olfactory bulb (OB). The migration in the RMS is characterised by a lack of dispersion of neuroblasts into the surrounding tissues and a highly directed motion towards the OB. This study uses a simple mathematical model to investigate several theories of migration of neuroblasts through the RMS proposed in the literature, including chemo-attraction, chemorepulsion, general inhibition and the presence of a migration-inducing protein. Apart from the general inhibition model, all the models were able to provide results in good qualitative correspondence with the experimental observations.


Assuntos
Encéfalo/fisiologia , Movimento Celular , Modelos Neurológicos , Células-Tronco Neurais/fisiologia , Neurogênese , Animais , Encéfalo/citologia , Bulbo Olfatório/metabolismo , Bulbo Olfatório/fisiologia
16.
J Infect Dis ; 205(9): 1374-81, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22454468

RESUMO

BACKGROUND: Acute gastroenteritis (AGE) remains a common cause of clinic visits and hospitalizations in the United States, but the etiology is rarely determined. METHODS: We performed a prospective, multicenter emergency department-based study of adults with AGE. Subjects were interviewed on presentation and 3-4 weeks later. Serum samples, rectal swab specimens, and/or whole stool specimens were collected at presentation, and serum was collected 3-4 weeks later. Fecal specimens were tested for a comprehensive panel of viral, bacterial, and parasitic pathogens; serum was tested for calicivirus antibodies. RESULTS: Pathogens were detected in 25% of 364 subjects, including 49% who provided a whole stool specimen. The most commonly detected pathogens were norovirus (26%), rotavirus (18%), and Salmonella species (5.3%). Pathogens were detected significantly more often from whole stool samples versus a rectal swab specimen alone. Nine percent of subjects who provided whole stool samples had >1 pathogen identified. CONCLUSIONS: Viruses, especially noroviruses, play a major role as agents of severe diarrhea in adults. Further studies to confirm the unexpectedly high prevalence of rotaviruses and to explore the causes of illness among patients from whom a pathogen cannot be determined are needed. Studies of enteric pathogens should require the collection of whole stool samples.


Assuntos
Serviço Hospitalar de Emergência , Gastroenterite/etiologia , Doença Aguda , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Caliciviridae/isolamento & purificação , Caliciviridae/patogenicidade , Infecções por Caliciviridae/complicações , Diarreia/epidemiologia , Diarreia/microbiologia , Diarreia/virologia , Fezes/microbiologia , Fezes/virologia , Feminino , Gastroenterite/microbiologia , Gastroenterite/parasitologia , Gastroenterite/virologia , Hospitalização , Humanos , Entrevistas como Assunto , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Prospectivos , Salmonella/isolamento & purificação , Salmonella/patogenicidade , Infecções por Salmonella/complicações , Manejo de Espécimes/métodos , Inquéritos e Questionários , Estados Unidos/epidemiologia , Adulto Jovem
17.
Immunol Rev ; 245(1): 189-208, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22168421

RESUMO

Nearly all human beings, by the time they reach adolescence, are infected with multiple herpesviruses. At any given time, this family of viruses accounts for 35-40 billion human infections worldwide, making herpesviruses among the most prevalent pathogens known to exist. Compared to most other viruses, herpesviruses are also unique in that infection lasts the life of the host. Remarkably, despite their prevalence and persistence, little is known about how these viruses interact with their hosts, especially during the clinically asymptomatic phase of infection referred to as latency. This review explores data in human and animal systems that reveal the ability of latent herpesviruses to modulate the immune response to self and environmental antigens. From the perspective of the host, there are both potentially detrimental and surprisingly beneficial effects of this lifelong interaction. The realization that latent herpesvirus infection modulates immune responses in asymptomatic hosts forces us to reconsider what constitutes a 'normal' immune system in a healthy individual.


Assuntos
Infecções por Herpesviridae/imunologia , Herpesviridae/fisiologia , Imunomodulação , Animais , Modelos Animais de Doenças , Infecções por Herpesviridae/virologia , Interações Hospedeiro-Patógeno/imunologia , Humanos , Latência Viral
18.
PLoS Pathog ; 7(11): e1002371, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22114555

RESUMO

The gammaherpesviruses, including Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV), establish latency in memory B lymphocytes and promote lymphoproliferative disease in immunocompromised individuals. The precise immune mechanisms that prevent gammaherpesvirus reactivation and tumorigenesis are poorly defined. Murine gammaherpesvirus 68 (MHV68) is closely related to EBV and KSHV, and type I (alpha/beta) interferons (IFNαß) regulate MHV68 reactivation from both B cells and macrophages by unknown mechanisms. Here we demonstrate that IFNß is highly upregulated during latent infection, in the absence of detectable MHV68 replication. We identify an interferon-stimulated response element (ISRE) in the MHV68 M2 gene promoter that is bound by the IFNαß-induced transcriptional repressor IRF2 during latency in vivo. The M2 protein regulates B cell signaling to promote establishment of latency and reactivation. Virus lacking the M2 ISRE (ISREΔ) overexpresses M2 mRNA and displays uncontrolled acute replication in vivo, higher latent viral load, and aberrantly high reactivation from latency. These phenotypes of the ISREΔ mutant are B-cell-specific, require IRF2, and correlate with a significant increase in virulence in a model of acute viral pneumonia. We therefore identify a mechanism by which a gammaherpesvirus subverts host IFNαß signaling in a surprisingly cooperative manner, to directly repress viral replication and reactivation and enforce latency, thereby minimizing acute host disease. Since we find ISREs 5' to the major lymphocyte latency genes of multiple rodent, primate, and human gammaherpesviruses, we propose that cooperative subversion of IFNαß-induced IRFs to promote latent infection is an ancient strategy that ensures a stable, minimally-pathogenic virus-host relationship.


Assuntos
Gammaherpesvirinae/genética , Fator Regulador 2 de Interferon/fisiologia , Fatores Reguladores de Interferon/fisiologia , Interferon-alfa/fisiologia , Interferon beta/fisiologia , Proteínas Virais/fisiologia , Latência Viral/fisiologia , Animais , Linfócitos B/virologia , Infecções por Herpesviridae/fisiopatologia , Interações Hospedeiro-Patógeno/fisiologia , Camundongos , Regiões Promotoras Genéticas/fisiologia , Elementos de Resposta/genética , Transdução de Sinais , Regulação para Cima , Proteínas Virais/biossíntese , Replicação Viral
19.
Public Health Rep ; 126(2): 251-8, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21387955

RESUMO

OBJECTIVES: The role of noroviruses in both foodborne and person-to-person outbreaks of acute gastroenteritis (AGE) has been difficult to determine in the U.S. because of lack of routine norovirus testing and of national reporting of person-to-person outbreaks. We conducted a prospective study in one state in which enhanced testing for noroviruses was performed to better understand the relative contribution of all gastroenteric pathogens. METHODS: During the two-year period, 2000-2001, we took all fecal specimens from AGE outbreaks reported in Georgia that were negative for bacteria and tested these for norovirus. RESULTS: We investigated 78 AGE outbreaks, from which suitable fecal samples were collected from 57 of them. Norovirus was identified in 25 (44%) outbreaks, bacteria in 20 (35%) outbreaks, and parasites in one (2%) outbreak. Forty-three (75%) of the outbreaks tested were foodborne, of which 17 (40%) were attributable to norovirus and 18 (42%) were attributable to bacteria. Adjusting for incomplete testing, we estimated that 53% of all AGE outbreaks were attributable to norovirus. A total of 2,674 people were reported ill in the 57 outbreaks, and norovirus infections accounted for 1,735 (65%) of these cases. Norovirus outbreaks tended to be larger than bacterial outbreaks, with a median number of 30 vs. 16 cases per outbreak, respectively (p = 0.057). CONCLUSIONS: This study provides further evidence that noroviruses are, overall, the most common cause of AGE outbreaks in the U.S. Improved specimen collection, reporting person-to-person outbreaks, and access to molecular assays are needed to further understand the role of these viruses and methods for their prevention.


Assuntos
Infecções por Caliciviridae/epidemiologia , Fezes/virologia , Gastroenterite/epidemiologia , Gastroenterite/virologia , Norovirus , Vigilância de Evento Sentinela , Infecções por Caliciviridae/transmissão , Fezes/microbiologia , Gastroenterite/microbiologia , Georgia/epidemiologia , Humanos , Estudos Prospectivos
20.
Br J Cancer ; 104(4): 620-8, 2011 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-21285990

RESUMO

BACKGROUND: The role of further hormone therapy in castration-resistant prostate cancer (CRPC) remains unclear. We performed a multi-centre randomised phase III study comparing the use of Dexamethasone, Aspirin, and immediate addition of Diethylstilbestrol (DAiS) vs Dexamethasone, Aspirin, and deferred (until disease progression) addition of Diethylstilbestrol (DAdS). METHODS: From 2001 to 2008, 270 men with chemotherapy-naive CRPC were randomly assigned, in a 1 : 1 ratio, to receive either DAiS or DAdS. They were stratified for performance status, presence of bone metastases, and previous normalisation of prostate-specific antigen (PSA) to androgen deprivation. The study end points were the proportion of patients achieving a 50% PSA response, progression-free survival (PFS), overall survival, and quality of life. Intention-to-treat analysis was carried out. The effect of treatment was studied first by Kaplan-Meier curves and log-rank test, and finally through multivariable stratified Cox's proportional hazards model adjusting for the effects of possible baseline prognostic factors. Quality of life was analysed using multivariate analysis of variance. RESULTS: At study entry, the median age was 76 years (inter-quartile range: 70-80 years), the median PSA was 79 ng ml(-1), and 76% of the cohort had metastatic disease. The response rates for DAiS (68%) and DAdS (64%) were not significantly different (P=0.49). Similar to the response rate, neither the PFS (median=8.1 months for both arms) nor the overall survival (19.4 vs 18.8 months) differed significantly between the DAiS and DAdS groups (P>0.20). However, the response rate for the DAiS (68%) was significantly higher than the response rate of DA (before adding Diethylstilbestrol) (50%) (P=0.002). Similarly, the median time to progression for DAiS (8.6 months) was significantly longer than that of DA (4.5 months) (P<0.001). Multivariable analysis showed that patients with previous haemoglobin ≥11 g dl(-1) decreased the risk of death significantly (hazard ratio: 0.44, 95% CI: 0.25-0.77). Patients treated with previous anti-androgens alone had more than 5 times more risk of death compared with patients treated with gonadorelin analogues throughout their castration-sensitive phase. Treatment sequencing did not affect the quality of life but pre-treatment performance status did. The incidence of veno-thromboembolic events was 22% (n=28) in DAiS and 11% (n=14) in the DA arm (P=0.02). Painful gynaecomastia occurred in only 1% on DA, whereas in 40% on DAiS (P=0.001). CONCLUSION: Dexamethasone and immediate Diethylstilbestrol resulted in neither higher PSA response rate nor higher PFS compared with Dexamethasone with deferred Diethylstilbestrol. There was no suggestion of significantly improved overall survival or quality of life. Given the significantly higher toxicity of Diethylstilbestrol, deferring Diethylstilbestrol until failure of Dexamethasone is the preferred strategy when using these agents in CRPC.


Assuntos
Carcinoma/tratamento farmacológico , Dexametasona/administração & dosagem , Dietilestilbestrol/administração & dosagem , Neoplasias da Próstata/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Antagonistas de Androgênios/administração & dosagem , Antagonistas de Androgênios/efeitos adversos , Antineoplásicos Hormonais/administração & dosagem , Antineoplásicos Hormonais/efeitos adversos , Carcinoma/patologia , Carcinoma/cirurgia , Dexametasona/efeitos adversos , Dietilestilbestrol/efeitos adversos , Progressão da Doença , Esquema de Medicação , Combinação de Medicamentos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/epidemiologia , Humanos , Masculino , Orquiectomia , Neoplasias da Próstata/patologia , Neoplasias da Próstata/cirurgia , Falha de Tratamento , Resultado do Tratamento
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