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C B Bruce

Publications and source records attributed to C B Bruce.

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A novel method of typing rhinoviruses using the product of a polymerase chain reaction.

At present rhinoviruses are detected and serotyped in tissue cultures, a slow and laborious process. Previously we have described how the polymerase chain reaction can be used as a rapid method for detecting the presence of a rhinovirus, or enterovirus, in clinical samples without the need to culture. Here we describe a new method which uses the product of the polymerase chain reaction to determine the type of the rhinovirus. The technique is rapid and simple and should eventually greatly facilitate studies on rhinovirus infections.

Gene Amplification

Amplification of rhinovirus specific nucleic acids from clinical samples using the polymerase chain reaction.

We describe a novel method for the detection of human rhinoviruses in clinical samples, using the polymerase chain reaction. Two synthetic oligonucleotide primers were produced that bind in the 5' noncoding region of all rhinovirus serotypes tested, about 350 nucleotides apart, and were used to prime polymerase chain reaction amplification of the intervening stretch of DNA. The product of this reaction, which can be clearly visualized by gel electrophoresis, is a discrete 380 bp band, the occurrence of which is diagnostic of the presence of a rhinovirus in the clinical sample analysed. The technique, which is rapid, sensitive, and reliable, has been used successfully for all the different rhinovirus serotypes tested to date in our laboratory. However, the sensitivity of detection is greatly dependent on the inclusion of both tRNA and vanadyl complexes during the viral RNA extraction process. Using this technique, under optimal conditions, we were able to detect virus in clinical samples with titres as low as TCID50 10(2.5).

Base Sequence

Use of synthetic oligonucleotide probes to detect rhinovirus RNA.

Current methods of detecting a human rhinovirus (HRV) infection are either based on isolation of virus in appropriate susceptible cell lines, which is time-consuming and requires considerable expertise, or are dependent on knowing the serotype. The existence of over 100 immunologically distinct serotypes makes serotype specific assays, such as ELISA, unsuitable for general diagnostic assays. In this study a general rhinovirus assay is described which utilises synthetic oligonucleotides as probes in a filter hybridization assay. The probes are designed to bind to short but highly conserved regions of the rhinovirus genome. Indeed, the probes successfully detected all 57 rhinovirus serotypes tested. Furthermore, the test was used to demonstrate rhinovirus infection in clinical samples from 57 volunteers, inoculated with HRV, collected on six consecutive days. Clinical samples were taken prior to inoculation and on days 2-7 after inoculation. The filter hybridization assay gave results comparable to virus culture on days 2 and 3 post-inoculation, but was more sensitive on subsequent days.

Base Sequence

Infection of rat brain primary cell cultures with an avirulent A7 strain of Semliki Forest virus.

The ability of A7 Semliki Forest Virus (SFV) to infect primary brain cell cultures has been examined using cultures prepared from 1-2-day neonatal rat cerebral hemispheres. These cultures, characterised immunocytochemically using cell-specified markers, contain mainly GFAP+ protoplasmic astrocytes and smaller multiprocessed A2B5+ cells, probably fibrous astrocytes. 10% of the cells are GC+ oligodendrocytes and some neurones are also present. These cultures support virus growth and a cytopathic effect was observed. Using double labelling techniques with the cell-specific markers and anti-SFV antibody A7 has been shown to readily infect cells which carry either the A2B5+ antigen or galactocerebroside marker. Protoplasmic astrocytes (GFAP+/A2B5-) are not readily infected under the conditions used. The protein labelling studies using [35S]methionine show that host cell protein synthesis is not completely shut off and continues in the astrocyte protein region. These results suggest that cells derived from a common A2B5+, GFAP-, GC- progenitor glial cell, i.e. GC+ oligodendrocytes and A2B5+/GFAP+ fibrous astrocytes, are more readily infected than other brain cell types including the protoplasmic astrocytes.

Animals

Immunocytochemical characterisation of cell cultures grown from dissociated 1-2-day post-natal rat cerebral tissue. A developmental study.

A range of cell-specific markers have been employed with immunocytochemical methods to characterise and quantitate the cell types present in mixed brain cell cultures derived from dissociated 1-2-day post-natal rat cerebral hemispheres and grown in the presence of FCS. Protoplasmic astrocytes (GFAP+, A2B5-) were the major cell type to develop in culture, a confluent monolayer forming in 5-8 days. A population of smaller round cells of oligodendrocyte-like morphology appeared on this astrocyte layer. Greater than 70% of these smaller cells were GC- and thus were not oligodendrocytes. The GC- cells were A2B5+ and, in early cultures, may therefore be progenitor glial cells. Examination of GFAP and A2B5 co-expression by these smaller cells was difficult due to the dense underlying GFAP+ astrocyte layer. In less dense areas of older cultures these smaller cells with processes were GFAP+ and A2B5+: these are Type 2, fibrous astrocytes. GC+ oligodendrocytes, comprising 5-10% of the total identified cell population, were initially distributed over the astrocyte monolayer; in older cultures (after about 8 days) GC+ cells were observed in clumps over places where NF+ cells were identifiable. Such GC+ cells mostly became MBP+. Neurones accounted for about 6% of the identifiable cells in early cultures but a lower percentage in older cultures. Minor populations of ependymal cells and macrophages were present; cells displaying fibronectin, fibroblasts, were rarely identified. Use of horse serum in place of FCS gave lower yields of GC+ cells in cultures, slowed down astrocyte development, and resulted in the formation of trunks of GFAP+ cells throughout cultures. Other sera gave lower numbers of GC+ cells.

Animals

A helix-destabilising protein from herpes simplex virus type I infected cells which specifically stimulates the virus induced DNA polymerase activity in vitro.

We have isolated a protein fraction from HSV-1 infected cells which binds specifically to single-stranded DNA, facilitates a lowering of the melting temperature of poly[d(A-T)] and specifically stimulates the activity of the homologous virus-induced DNA-dependent DNA polymerase in vitro. These are major characteristics of a helix-destabilising protein, exemplified by the prokaryotic gene 32 protein.

DNA-Binding Proteins

[Stuttering].

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Humans