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Journal of virology ; 79(6): 3807-3821, Mar. 2005. graf, tab, ilus
Artigo em Inglês | MedCarib | ID: med-17658


The 3' noncoding region (3' NCR) of flaviviruses contains secondary and tertiary structures essential for virus replication. Previous studies of yellow fever virus (YFV) and dengue virus have found that modifications to the 3' NCR are sometimes associated with attenuation in vertebrate and/or mosquito hosts. The 3' NCRs of 117 isolates of South American YFV have been examined, and major deletions and/or duplications of conserved RNA structures have been identified in several wild-type isolates. Nineteen isolates (designated YF-XL isolates) from Brazil, Trinidad, and Venezuela, dating from 1973 to 2001, exhibited a 216-nucleotide (nt) duplication, yielding a tandem repeat of conserved hairpin, stem-loop, dumbbell, and pseudoknot structures. YF-XL isolates were found exclusively within one subclade of South American genotype I YFV. One Brazilian isolate exhibited, in addition to the 216-nt duplication, a deletion of a 40-nt repeated hairpin (RYF) motif (YF-XL-DeltaRYF). To investigate the biological significance of these 3' NCR rearrangements, YF-XL-DeltaRYF and YF-XL isolates, as well as other South American YFV isolates, were evaluated for three phenotypes: growth kinetics in cell culture, neuroinvasiveness in suckling mice, and ability to replicate and produce disseminated infections in Aedes aegypti mosquitoes. YF-XL-DeltaRYF and YF-XL isolates showed growth kinetics and neuroinvasive characteristics comparable to those of typical South American YFV isolates, and mosquito infectivity trials demonstrated that both types of 3' NCR variants were capable of replication and dissemination in a laboratory-adapted colony of A. aegypti.

Camundongos , Animais , Humanos , Research Support, Non-U.S. Gov't , Research Support, U.S. Gov't, P.H.S. , Aedes/virologia , Sequência de Bases , Células Cultivadas , Variação Genética , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Filogenia , RNA não Traduzido/química , RNA não Traduzido/genética , RNA não Traduzido/fisiologia , RNA Viral/química , RNA Viral/genética , RNA Viral/fisiologia , Vírus da Febre Amarela/classificação , Vírus da Febre Amarela/crescimento & desenvolvimento , Vírus da Febre Amarela/genética , Vírus da Febre Amarela/isolamento & purificação , Vírus da Febre Amarela/patogenicidade , Trinidad e Tobago , Brasil , Venezuela
Proc Natl Acad Sci U S A ; 86(6): 2021-5, Mar. 1989.
Artigo em Inglês | MedCarib | ID: med-12266


The isolation and characterization of a human T-cell lymphotrophic virus type I (HTLV-I) from cerebrospinal fluid of a Jamaican patient with tropical spastic paraparesis is described. The virus isolate is a typical type C retrovirus as seen by electron microscopy and is related to prototype HTLV-I isolated from patients with adult T-cell leukemia but is not identical to this prototype HTLV-I as seen by restriction enzyme mapping.(AU)

Humanos , Idoso , Feminino , Líquido Cefalorraquidiano/microbiologia , Vírus Linfotrópico T Tipo 1 Humano/isolamento & purificação , Paraparesia Espástica Tropical/microbiologia , Células Cultivadas , Enzimas de Restrição do DNA , DNA Viral/análise , Imunofluorescência , Jamaica , Leucemia , Leucemia de Células T/microbiologia , Leucócitos Mononucleares/microbiologia , Microscopia Eletrônica , Paraparesia Espástica Tropical/imunologia , DNA Polimerase Dirigida por RNA/análise
Int J Cancer ; 38(1): 41-5, July 1986.
Artigo em Inglês | MedCarib | ID: med-13285


Six healthy relatives of 3 adult T-cell leukemia lymphoma (ATLL) patients and 6 members of a Caribbean family immigrant to the UK have been investigated for the presence of HTLV-I and expression of interleukin 2(IL-2) receptors. Serum antibodies to HTLV-I were detected in all but 4 samples. Four to 10 percent of circulating cells from 3/4 seropositive donors studied displayed IL-2 receptors (anti-Tac+) and were shown to be convoluted lymphocytes by light microscopy morphology and immunoelectromicroscopy. After 5 to 28 days in culture, cells from 4 seropositive donors reacted with monoclonal antibodies (MAbs) against the HTLV-I core proteins, p19 and p24, and released retrovirus particles. Simmilar experiments with blood from 3 seronegative donors from the same families and 4 normal controls proved negative. Our findings indicate that seropositive individuals harbour the virus in a population of T-lymphocytes which may then acquire receptors for IL-2. These individuals are at risk of developing ATLL. (AU)

Humanos , Portador Sadio/microbiologia , Leucemia/microbiologia , Infecções por Retroviridae/microbiologia , Anticorpos Antivirais/análise , Portador Sadio/sangue , Células Cultivadas , Reino Unido , Deltaretrovirus/imunologia , Técnicas Imunoenzimáticas , Leucemia/sangue , Linfócitos/imunologia , Linfócitos/ultraestrutura , Receptores de Antígenos de Linfócitos T/imunologia , Receptores Imunológicos/imunologia , Proteínas do Core Viral/análise , Vírion/ultraestrutura , Índias Ocidentais/etnologia
Am J Trop Med Hyg ; 35(2): 393-400, Mar. 1986.
Artigo em Inglês | MedCarib | ID: med-10892


Twenty-one dengue (DEN) viruses isolated from the Caribbean (Dominica and Jamaica) during the 1981-1982 epidemic year were distinct serological and genetic variants of DEN-4 virus. These isolates were clearly identified as DEN-4 viruses using type-specific monoclonal antibodies in indirect immunofluorescence assays. However, they either were not neutralized, or were neutralized poorly using hyperimmune mouse ascitic fluids (HMAF) or rhesus monkey serum directed against the H-241 prototype strain of DEN-4 virus isolated in the Philippines in 1956. HMAF prepared against a representative Caribbean isolate, however, neutralized with similar effectiveness the homologoous virus, the H-241 prototype strain, and virus strains isolated from the Pacific and Southeast Asian areas from 1973 to 1984. The Caribbean isolate exhibited no more than 30 percent and 16 percent oligonucleotide spot homology with the H-241 and Bankok viruses, respectively, by RNA fingerprint analysis, while demonstrating 82 percent and 89 percent homology with the Gilbert and Niue Island isolates, respectively. The isolation of dengue viruses which are serologically and genetically distinct from the prototype virus emphasizes the need for continued dengue virus surveillance. The recognition of unique dengue isolates should allow the selection of reference strains and vaccine candidate strains which will induce antibodies that are equally effective in neutralizing virus from all geographic areas. (AU)

Humanos , Camundongos , 21003 , Vírus da Dengue/genética , Aedes/microbiologia , Anticorpos Monoclonais/diagnóstico , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/isolamento & purificação , Antígenos Virais/imunologia , Antígenos Virais/isolamento & purificação , Células Cultivadas , Vírus da Dengue/imunologia , Vírus da Dengue/isolamento & purificação , República Dominicana , Imunofluorescência , Jamaica , Testes de Neutralização , Ensaio de Placa Viral , RNA Viral/isolamento & purificação
Int J Cancer ; 30(3): 257-64, Sept. 15 1982.
Artigo em Inglês | MedCarib | ID: med-14448


Type-C RNA tumour viruses have been implicated in the etiology of naturally occurring leukemias and lymphomas of animals. Human T-cell leukimia/lymphoma virus (HTLV) is the first human virus of this class consistently identified in association with a specific type of human leukemia/lymphoma. The isolation of HTLV was made possible by the ability to grow mature T-cell in tissue culture usually with T-cell growth factor (TCGF). We now report a cluster usually with T-cell leukemia/lymphoma among Blacks from the Caribbean in which all eight cases are positive for HLV virus and/or antibody. These patients have diseases that appears indistinguisable from Japanese adult T-cell leukemia/lymphoma which, as we have also reported, is associated with HTLV in over 90 percent of cases. The finding of HTLV antibodies in some of the normal population in the Caribbean and Japan, and the clustering of a specific form of T-cell leukemia/lyphoma in these virus-endemic areas, suggest that HTLV infection may be associated with the occurrence of a distinctive clinico-pathologic entity (Summary)

Humanos , Adolescente , Adulto , Pessoa de Meia-Idade , 21003 , Masculino , Feminino , Leucemia/imunologia , Linfoma/imunologia , Retroviridae/imunologia , Infecções Tumorais por Vírus/imunologia , Anticorpos Antivirais/análise , Antígenos Virais/análise , Células Cultivadas , Leucemia/patologia , Linfoma/patologia , Radioimunoensaio , Linfócitos T , Índias Ocidentais
West Indian med. j ; 10(2): 132, June 1961.
Artigo em Inglês | MedCarib | ID: med-7598


During the period 1952-1959 there were two major epidemics of typhoid in Jamaica and 121 documented cases of typhoid infection were treated at the University College Hospital. Diagnosis was made mainly on culture of the organism and less reliance was placed on Widal agglutinations as T.A.B. inoculations are frequently given prophylactically in Jamaica. This disease was found to be mainly one of the young age groups. Although most cases responded to treatment, there was a relapse rate of 8 percent. Despite chloramphenicol, deaths continue to occur and a mortality rate of 5.8 percent found. The cost of treatment runs to thousands of pounds - a wasteful effort against a preventable disease (AU)

Humanos , Febre Tifoide/diagnóstico , Jamaica , Células Cultivadas , Cloranfenicol/uso terapêutico