Search PubMed⌕ Search

Biomedical subjects

R A Hall

Publications and source records attributed to R A Hall.

153 records · Page 9Linked to original sources
PubMedDate not supplied

Antibodies to Japanese encephalitis virus in human sera collected from Irian Jaya. Follow-up of a previously reported case of Japanese encephalitis in that region.

Japanese encephalitis virus (JEV) and other arboviruses are demonstrating an emergence in the southern part of New Guinea Island. JE was previously unknown in this part of the world until 1995 when it was found in the Torres Strait, northern Australia. In this study 96 sera collected from residents of the Timika region of Irian Jaya were tested for antibodies to JEV and related arboviruses by epitope-specific blocking ELISA. Of the 9 sera deemed to be positive for JEV antibodies by ELISA, 5 were collected from persons indigenous to Timika, and who had not travelled to regions where JE is known to be active. This indicates that these individuals were infected with JEV in the Timika area and supports a recent report of a clinical case of JE in this region. Non-immune expatriates visiting or working in the Lowland areas of Irian Jaya and/or Papua New Guinea should consider immunization against JE. Precautions should always be taken to avoid being bitten by any mosquito both in the daytime and at night.

Antibodies, Viral↗
PubMedDate not supplied

Biochemistry of intervertebral disc degeneration and the potential for gene therapy applications.

BACKGROUND CONTEXT: Low back pain continues to be a major cause of morbidity in the United States and the world. Although the exact cause has yet to be defined, the intervertebral disk and its age-related changes have been most frequently implicated. PURPOSE: This article represents a brief summary of intervertebral disk structure and function, both in the "normal" and degenerative states. STUDY DESIGN/SETTING: Review article. A Medline search from 1966 to present was performed to identify pertinent articles related to the topic of the intervertebral disc and degeneration. METHODS: This review article describes the pertinent anatomy, as well as the biochemical and biomechanical changes that occur in the intervertebral disc over time. It presents many of the current theories implicated as causing these changes. RESULTS: Recent studies have shown that gene therapy (the transfer of therapeutic gene[s] into a cell), may have promise as a method of slowing down, or preventing some of the changes seen in the intervertebral disc. CONCLUSION: Intervertebral disc degeneration is a complex phenomenon, likely the result of a combination of biochemical and biomechanical factors that are known to occur in the disk. Ongoing research efforts in the area of gene therapy show promise as a way to prevent, or even reverse, some of these changes.

Adult↗
PubMedDate not supplied

Polymerase chain reaction tests for the identification of Ross River, Kunjin and Murray Valley encephalitis virus infections in horses.

OBJECTIVE: To develop and validate specific, sensitive and rapid diagnostic tests using RT-PCR for the detection of Ross River virus (RRV), Kunjin virus (KV) and Murray Valley encephalitis virus (MVEV) infections in horses. METHODS: Primer sets based on nucleotide sequence encoding the envelope glycoprotein E2 of RRV and on the nonstructural protein 5 (NS5) of KV and MVEV were designed and used in single round PCRs to test for the respective viruses in infected cell cultures and, in the case of RRV, in samples of horse blood and synovial fluid. RESULTS: The primer pairs designed for each of the three viruses amplified a product of expected size from prototype viruses that were grown in cell culture. The identity of each of the products was confirmed by nucleotide sequencing indicating that in the context used the RT-PCRs were specific. RRV was detected in serums from 8 horses for which there were clinical signs consistent with RRV infection such that an acute-phase serum sample was taken and submitted for RRV serology testing. The RRV RT-PCR was analytically sensitive in that it was estimated to detect as little as 50 TCID50 of RRV per mL of serum and was specific in that the primer pairs did not amplify other products from the 8 serum samples. The RRV primers also detected virus in three independent mosquito pools known to contain RRV by virus isolation in cell culture. Samples from horses suspected to be infected with KV and MVEV were not available. CONCLUSION: Despite much anecdotal and serological evidence for infection of horses with RRV actual infection and associated clinical disease are infrequently confirmed. The availability of a specific and analytically sensitive RT-PCR for the detection of RRV provides additional opportunities to confirm the presence of this virus in clinical samples. The RT-PCR primers for the diagnosis of KV and MVEV infections were shown to be specific for cell culture grown viruses but the further validation of these tests requires the availability of appropriate clinical samples from infected horses.

Alphavirus Infections↗
PubMedDate not supplied

The relationships between West Nile and Kunjin viruses.

Until recently, West Nile (WN) and Kunjin (KUN) viruses were classified as distinct types in the Flavivirus genus. However, genetic and antigenic studies on isolates of these two viruses indicate that the relationship between them is more complex. To better define this relationship, we performed sequence analyses on 32 isolates of KUN virus and 28 isolates of WN virus from different geographic areas, including a WN isolate from the recent outbreak in New York. Sequence comparisons showed that the KUN virus isolates from Australia were tightly grouped but that the WN virus isolates exhibited substantial divergence and could be differentiated into four distinct groups. KUN virus isolates from Australia were antigenically homologous and distinct from the WN isolates and a Malaysian KUN virus. Our results suggest that KUN and WN viruses comprise a group of closely related viruses that can be differentiated into subgroups on the basis of genetic and antigenic analyses.

Aedes↗