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Biomedical subjects

T Barrett

Publications and source records attributed to T Barrett.

At least 145 records · Page 8Linked to original sources

Cloning and sequence analysis of the phosphoprotein gene of rinderpest virus.

We have cloned several cDNAs derived from the P gene of rinderpest virus. One of these, derived from a bicistronic N-P mRNA, has been sequenced in its entirety. Sequencing of a section of the others, and comparison with the genome sequence, showed that P gene transcripts, as for other morbilliviruses, were variable; non-templated Gs could be added at a site resembling the normal stop transcription site. Primer extension analysis showed that about half the transcripts were edited. Sequences of the P, C and V proteins encoded by the normal and edited transcripts were compared with those of other morbilliviruses and with those of the more distantly related paramyxoviruses.

Amino Acid Sequence↗

Viral antigen distribution in organs of cattle experimentally infected with rinderpest virus.

The distribution of viral antigen in various organs of four approximately 10-month-old castrated male Friesian cattle experimentally infected with a highly virulent strain of rinderpest virus was studied. A monoclonal antibody with genus-specific reactivity for morbilliviruses was applied in an indirect immunoperoxidase method performed on formalin-fixed, paraffin-embedded tissue sections. Rinderpest viral antigen was located mainly in the cytoplasm of the epithelial cells of the digestive, respiratory, and urinary tracts, as well as in the cells of endocrine glands (adrenal, thyroid) and exocrine glands (salivary glands, sebaceous glands, exocrine pancreas). Furthermore, different types of cells in lymphatic organs contained rinderpest viral antigen. In contrast to the documented results of studies carried out with other morbilliviruses, tissues of the central nervous system did not contain viral antigen. Various types of epithelial and lymphoreticular cells are the main targets of a virulent strain of rinderpest virus in vivo.

Animals↗

Use of the polymerase chain reaction in differentiating rinderpest field virus and vaccine virus in the same animals.

In 1991, a disease with clinical signs indicative of rinderpest was reported in yaks in the former Soviet Union, near the border with Mongolia. At the peak of the epizootic, mortality among affected yaks was 32-42% in adults and 65% in animals less than one year old. Pathological samples were examined independently at two institutes in Russia. Both institutes confirmed the presence of rinderpest using complement fixation, agar gel diffusion and immunoassays. Since vaccination had been initiated to control an outbreak of a similar disease several months earlier, the later cases were possibly due to the vaccine and field rinderpest may not have been present. However, the disease had occurred in non-vaccinated animals and these were then vaccinated against the disease. Tissue samples obtained from these animals, which were examined at the Pirbright Laboratory using gel diffusion assays and specific nucleic acid probes, were found to be positive for rinderpest antigen and nucleic acid. Ribonucleic acid derived from the post-mortem tissue samples was amplified using the polymerase chain reaction and rinderpest-specific primers. Sequence analysis of the amplified deoxyribonculeic acid from the samples revealed the presence of two distinct virus strains, one identical to the Plowright rinderpest tissue culture vaccine and the other related to field strains of rinderpest virus circulating in Asia and the Middle East.

Animals↗

Morbillivirus infections in aquatic mammals.

Infections with morbilliviruses have caused heavy losses among different populations of aquatic mammals during the last 5 years. Two different morbilliviruses were isolated from disease outbreaks among seals in Europe and Siberia: phocid distemper virus-1 (PDV-1) and phocid distemper virus-2 (PDV-2) respectively. PDV-1 was characterized as a newly identified morbillivirus, most related to canine distemper virus (CDV), whereas PDV-2 most probably is a strain of CDV. Morbilliviruses were also isolated from porpoises--porpoise morbillivirus (PMV)--and dolphins--dolphin morbillivirus (DMV)--which had stranded on the coasts of Europe. PMV and DMV proved to be closely related to, but distinct from 2 ruminant morbilliviruses, rinderpest virus (RPV) and peste-des-petits-ruminants virus (PPRV). Serological surveys carried out among pinniped and cetacean species in the seas of Europe and North America indicated that infections with these newly discovered morbilliviruses or closely related viruses commonly occur among aquatic mammal species.

Animals↗

Molecular and serological studies on the recent seal virus epizootics in Europe and Siberia.

The virus epizootics which occurred in seals in both Europe and Siberia during 1987/1988 were caused by two different morbilliviruses, referred to as phocid distemper virus (PDV) 1 and 2, respectively. Molecular and serological studies have shown that the European virus is quite distinct from canine distemper virus (CDV), its closest relative in the morbillivirus group. Analysis of tissues obtained from infected seals from a wide geographical distribution over Northern Europe showed that the infectious agent (PDV 1) was identical in all cases. Nucleotide sequence analysis of one of the virus genes suggested that this virus has evolved away from CDV over a long time period and is most probably an enzootic virus of marine mammals. In contrast, the virus (PDV 2) which caused the deaths of many Siberian seals was indistinguishable, both serologically and at the molecular level, from CDV and must have originated from a land source.

Animals↗

Canine distemper virus ISCOMs induce protection in harbour seals (Phoca vitulina) against phocid distemper but still allow subsequent infection with phocid distemper virus-1.

A candidate canine distemper virus (CDV) ISCOM vaccine has been shown to be effective in protecting harbour seals (Phoca vitulina) from phocid distemper in 1988. However, of the 35 harbour seals receiving this vaccine upon admission to a seal rehabilitation and research centre (Pieterburen, The Netherlands) in 1989, six developed mild inflammatory symptoms of the respiratory tract. Phocid distemper virus-1 (PDV-1) could be isolated from three of these animals. This indicates that the vaccine affords protection from phocid distemper, but may still allow PDV-1 infection of the respiratory tract. Contacts with non-vaccinated seals should then be prevented until no more virus is excreted. It is speculated that this PDV-1 infection of the respiratory tract in CDV-ISCOM vaccinated seals is followed by a lifelong immunity.

Animals↗

Round table on morbilliviruses in marine mammals.

Since 1988 morbilliviruses have been increasingly recognized and held responsible for mass mortality amongst harbour seals (Phoca vitulina) and other seal species. Virus isolations and characterization proved that morbilliviruses from seals in Northwest Europe were genetically distinct from other known members of this group including canine distemper virus (CDV), rinderpest virus, peste des petits ruminants virus and measles virus. An epidemic in Baikal seals in 1987 was apparently caused by a morbillivirus closely related to CDV so that two morbilliviruses have now been identified in two geographically distant seal populations, with only the group of isolates from Northwest Europe forming a new member of the genus morbillivirus: phocid distemper virus (PDV). Because of distemper-like disease, the Baikal seal morbillivirus was tentatively named PDV-2 in spite of its possible identity with CDV. The appearance of morbilliviruses in the Mediterranean Sea causing high mortality amongst dolphins should further increase the research activities on protection strategies for endangered species of marine mammals.

Animals↗

Arthritis outpatients: disability, pain and alcohol use.

There is a small body of literature describing investigations into the relationships between pain and disabling conditions and alcohol consumption. Of these few studies, most have concluded that pain and disability are positively associated with alcohol consumption, though these particular studies have not been methodologically rigorous. Arthritis is the most prevalent of the disabling conditions, and one of the major symptoms of arthritis is pain. Several factors associated with the disease are thought to make arthritis sufferers particularly vulnerable to the use of alcohol for its mind-altering and analgesic properties. In the present study, conducted in 1987, a sample of 154 Perth arthritic outpatients were interviewed to investigate the relationship between pain, disability and alcohol consumption. Results showed that pain and disability scores were very weak predictors of volume of weekly alcohol consumption for males, but the relationship was in a negative direction. Results from a previous study were confirmed in the finding that being an ex-drinker was a predictor of a higher disability score for females. Fewer patients were drinkers than in the population at large and fewer drank at the level of the highest consumption category. However, the proportions of male and female patients drinking above NHMRC low risk levels were the same as the general population (age-standardised comparison). Most who considered themselves current drinkers said that alcohol did not help their pain, stiffness or weakness. Various possible explanations are offered for these results and recommendations for future research are presented.

Adolescent↗

Recognition and treatment of surgical wound infections.

1. Tissue traumatized by surgery heals in a three-phase sequential process: a defensive response to the injury, reconstruction of the site, and maturation (closing) of the wound. 2. Not all patients undergoing surgery are at equal risk for infection. The anatomic location of the surgery, the seeding of the surgical site with the patient's own normal flora, the OR environment and personnel, and the presence of a foreign body left in place after closure all contribute to the risk of infection. 3. The treatment of postoperative infection can be divided into the physical aspects of wound care and the appropriate use of antimicrobial agents.

Humans↗

Deduced amino acid sequence of the fusion glycoprotein of turkey rhinotracheitis virus has greater identity with that of human respiratory syncytial virus, a pneumovirus, than that of paramyxoviruses and morbilliviruses.

The sequence of the fusion (F) glycoprotein of turkey rhinotracheitis virus (TRTV) has been deduced from cDNA clones derived from oligo(dT)-selected infected cell RNA. The protein consists of 538 amino acids, the F2 and F1 subunits containing 102 (including the F2-F1 connecting peptide RRRR) and 436 residues, respectively. Each subunit has one potential N-linked glycosylation site. The protein has 38 to 39% amino acid identity with the F protein of respiratory syncytial virus (Pneumovirus genus) but only about half that with members of the other two genera (Paramyxovirus and Morbillivirus) in the Paramyxoviridae family. This is the first sequence evidence to support the view that TRTV is a pneumovirus, the first avian member of the genus to be described.

Amino Acid Sequence↗

Detection of phocid distemper virus RNA in seal tissues using slot hybridization and the polymerase chain reaction amplification assay: genetic evidence that the virus is distinct from canine distemper virus.

Slot hybridization and the polymerase chain reaction (PCR) after reverse transcription (RT) were used to detect RNA extracted from tissues of seals after naturally occurring disease and experimental infection with phocid distemper virus (PDV). A phosphoprotein (P) gene-specific cDNA served as a probe for both slot hybridization and the identification of PCR-generated fragments by Southern blotting. As primers for the PCR assay PDV P gene-derived oligonucleotides were used. Hybridization, PCR and partial nucleic acid sequence analysis clearly demonstrated that PDV is a distinct virus (most closely related to canine distemper virus) within the morbillivirus group. PCR, when combined with Southern blot hybridization, was clearly superior to slot hybridization and more sensitive than cell culture isolation and immunofluorescence assays for the detection of virus in tissues. Considerable amounts of viral RNA could be demonstrated in the lungs and spleens. In experimentally infected animals a large quantity of virus-specific RNA was additionally found in colon samples. Using RT-PCR in combination with Southern blotting. PDV could be demonstrated in buffy coat cells using a simple and fast cell lysis procedure.

Animals↗

The role of the 5' nontranslated regions of the fusion protein mRNAs of canine distemper virus and rinderpest virus.

The mRNAs which code for the fusion proteins of the morbilliviruses (measles virus, canine distemper virus, and rinderpest virus) have unusually long 5' untranslated regions (UTRs) which are GC-rich and are capable of folding into extensive secondary structures. In measles virus the first AUG codons in the fusion (F) protein mRNA are in close proximity at nucleotide positions 574 and 583 and protein translation is initiated at the second position. In the canine distemper virus (CDV) and rinderpest virus (RPV) F gene transcripts the analogous initiation codons are preceded by several other AUG codons many nucleotides upstream either in the same reading frame or at the beginning of other short open reading frames. We have studied the effect of deleting these upstream regions on the production of the fusion proteins of both CDV and RPV from cDNA constructs. Within the cells the presence of these regions enhances the production of the F protein while, in contrast, the production of the authentic F protein from in vitro translations using RNA transcripts is inhibited by these sequences.

Animals↗

Observations on the pathogenicity for sheep and goats and the transmissibility of the strain of virus isolated during the rinderpest outbreak in Sri Lanka in 1987.

The pathogenicity for sheep and goats of the virus strain that caused acute rinderpest in cattle and domestic buffalo in Sri Lanka after an interval of over 40 years has been examined. The results show that it can cause overt clinical disease in goats, but only mild or unapparent infection in sheep. The disease was transmitted from infected sheep to in-contact susceptible sheep and calves.

Animals↗

The epidemiology of peste des petits ruminants in the Sultanate of Oman.

Virological and serological evidence was obtained to show that peste des petits ruminants virus was widely distributed in Omani sheep and goats. There was no evidence for the concomitant presence of rinderpest virus in these species. Two virus isolates were classified as peste des petits ruminants virus on the basis of their pathogenicity in experimental animals and their specific hybridisation with nucleic acid probes. However, neutralisation tests and polyacrylamide gel analysis of their nucleocapsid proteins showed that they were not identical to the highly conserved African strains of this virus.

Age Factors↗