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Biomedical subjects

I G Wilson

Publications and source records attributed to I G Wilson.

30 records · Page 2Linked to original sources
PubMed1994

A non-isotopic DNA hybridisation assay for the identification of Staphylococcus aureus isolated from foods.

A digoxygenin-labelled total genomic DNA probe was used to identify Staphylococcus aureus. Isolation and identification of organisms was possible in less than 4 days. Identification alone could be completed in less than 2 days, compared with over 5 days for identification of isolates by multipoint inoculation. The probe showed excellent discrimination of S. aureus from other staphylococci and from a wide range of bacteria commonly associated with milk and meat. The effectiveness of this probe was tested against cultural isolation of staphylococci in milk using Baird-Parker agar followed by identification using multipoint inoculation and API Staph. The probe gave comparable results to the conventional methods and, for large sample numbers, offered lower cost and greater ease of use.

Animals↗
PubMed1994

Some factors inhibiting amplification of the Staphylococcus aureus enterotoxin C1 gene (sec+) by PCR.

PCR amplification of the sec+ gene for staphylococcal enterotoxin C1 (SEC1) can be achieved from as little as 10 fg total genomic DNA (equivalent to less than 10 cells) using two nested primer pairs. The presence of bacterial cells, particularly thermonuclease-producing staphylococci, and the thermonuclease enzyme (TNase) itself, were found to be factors which individually and together reduced the sensitivity of PCR amplification.

DNA, Bacterial↗
PubMed1992

Biophysical and biochemical properties of baculovirus-expressed CaMV P1 protein.

Cauliflower mosaic virus (CaMV) gene I encodes a protein (P1) that has been implicated in the control of virus movement in infected plants. To assist in the characterization of the mechanism of action of P1, gene I has been expressed efficiently in Spodoptera frugiperda (Sf) cells using recombinant baculovirus. Control of the expression of CaMV gene I by the polyhedrin late promoter in the baculovirus Autographa californica nuclear polyhedrosis virus (AcNPV) resulted in very high levels of P1 accumulation late in the infection cycle. This was predominantly as insoluble inclusion bodies within the cytoplasm of infected Sf cells, and not extracellularly. Evidence from anomalous gel migration and sequence homology with an analogous viral protein (tobacco mosaic virus 30K) indicated that P1 may be post-translationally processed. However, neither phosphorylation nor glycosylation of P1 occurred in this system, suggesting a functional distinction between P1 and TMV 30K. P1 from insect cells and native P1 from infected plants were immunologically related, allowing the expressed product to be used in the preparation of anti-P1 serum for detecting P1 in plant extracts. The full-size (46 kD) P1 product from insect cells, from plants, and from in vitro translations of in vitro gene I transcripts all showed similar behavior on two-dimensional protein gels, with a major pI of 7.0. Using a combination of 4 M urea, 1 M NaCl, and high temperature, P1 was solubilized. Approximately 5% of the starting material remained in solution after dialysis and remained stable to freeze/thawing. This preparation should enable us to identify the biochemical function of P1 and to resolve its role in controlling virus spread.

Animals↗
PubMed1992

Movements of the vocal cords on induction of anaesthesia with thiopentone or propofol.

Using a fibreoptic laryngoscope, we have recorded on video tape the movements of the vocal cords after induction of anaesthesia with either propofol or thiopentone. The angle formed by the vocal cords decreased after induction of anaesthesia in both groups. This reduction in angle was significantly greater in the thiopentone group. The vocal cords closed completely in four patients in the thiopentone group and one patient in the propofol group. This difference may be explained by greater depression of laryngeal reflexes by propofol and this may account for the lower incidence of laryngospasm after induction of anaesthesia with propofol in comparison with thiopentone.

Adult↗
PubMed1992

Cardiovascular responses to insertion of the laryngeal mask.

We have compared, in 40 healthy patients, the cardiovascular responses induced by laryngoscopy and intubation with those produced by insertion of a laryngeal mask. Anaesthesia was induced with thiopentone and maintained with enflurane and nitrous oxide in oxygen; vecuronium was used for muscle relaxation. Arterial pressure was measured with a Finapres monitor. The mean maximum increase in systolic arterial pressure after laryngoscopy and tracheal intubation was 51.3% compared with 22.9% for laryngeal mask insertion (p less than 0.01). Increases in maximum heart rate were similar, (26.6% v 25.7%) although heart rate remained elevated for longer after tracheal intubation. We conclude that insertion of the laryngeal mask airway is accompanied by smaller cardiovascular responses than those after laryngoscopy and intubation and that its use may be indicated in those patients in whom a marked pressor response would be deleterious.

Adult↗
PubMed1991

Intravenous lignocaine and sympathoadrenal responses to laryngoscopy and intubation. The effect of varying time of injection.

We have studied the effect of varying the timing of a prior dose of intravenous lignocaine 1.5 mg/kg on the cardiovascular and catecholamine responses to tracheal intubation. Forty healthy patients were given an intravenous injection of either placebo or lignocaine 2, 3 or 4 minutes before tracheal intubation. There was a significant increase in heart rate of 21-26% in all groups. There was no significant increase in mean arterial pressure in response to intubation in any group of patients given lignocaine before intubation, but in the placebo group, mean arterial pressure increased by 19.1% compared to baseline values (p less than 0.05).

Adult↗
PubMed1991

Detection of enterotoxigenic Staphylococcus aureus in dried skimmed milk: use of the polymerase chain reaction for amplification and detection of staphylococcal enterotoxin genes entB and entC1 and the thermonuclease gene nuc.

The polymerase chain reaction was used to amplify the staphylococcal enterotoxin B and C genes (entB and entC1) and the staphylococcal nuclease gene (nuc). Two sets of primers ("nested primers") were found to be necessary for the detection of low copy numbers of purified DNA in diluent. These allowed detection of ca. 1 fg of purified target DNA, while 100 pg was required before detection of entB, entC1, and nuc with single primer pairs was possible. With nested primers, enterotoxigenic Staphylococcus aureus cells could be detected in artificially contaminated dried skimmed milk samples at levels of ca. 10(5) CFU ml-1 within 8 h. No cross-reaction was observed between the highly homologous entB and entC1 genes. The method showed total specificity for entC1 when tested against a wide variety of other bacteria.

Animals↗
PubMed1989

The pattern of accumulation of cauliflower mosaic virus-specific products in infected turnips.

The concentrations of cauliflower mosaic virus (CaMV) DNA and protein products in the developing leaves of a host, turnip, have been measured and the results have been correlated with symptom production. Virus-specific products were limited to the symptomatic leaves. CaMV DNA was detected in the youngest foliar tissues showing full systemic symptoms and continued to accumulate as the leaf expanded, indicating that virus multiplication was not restricted to meristematic tissues of the host plant and that virus concentration was not a primary determinant for symptom production. Using specific antisera for Western blot analysis, the distribution of CaMV-specific proteins (P1-P6) in a range of subcellular fractions of infected tissue was determined. The protein products (P2-P6) of genes II-VI were all detected in fractions enriched for virus inclusion bodies, although P5 was present only at low levels. A high-speed pellet fraction enriched for virus replication complexes revealed P5 in higher concentrations, and also contained P4 and small amounts of P6 in proportions which indicated that replication complexes had been released from inclusion bodies. In the different leaves of the host, P2, 3, 4, 5, and 6 all increased in concentration in parallel with viral DNA, although there appeared to be a bias toward protein rather than DNA synthesis in the very young leaves. P1 showed a different pattern of accumulation; it was most concentrated in the very young and the oldest infected tissues, and showed a different spectrum of products between leaves. The experiments described provide a more complete picture of the relationship between CaMV multiplication and expression, and leaf development, and an increased understanding of how the disease syndrome is established.

Blotting, Western↗
PubMed1989

Identification and subcellular localization of a putative cell-to-cell transport protein from red clover mottle virus.

To investigate the mode of gene expression of red clover mottle virus (RCMV) middle component (M) RNA, we have synthesized an oligopeptide corresponding to the predicted carboxy-terminus of the RCMV counterparts of the cowpea mosaic virus (CPMV) 48K and 58K proteins. Using an antiserum raised against this synthetic oligopeptide, we have detected a 43-kDa protein in the 30,000 g pellet from extracts of RCMV-infected cowpea protoplasts. Immunogold cytochemistry further localized this protein to the plasmodesmata of RCMV-infected pea tissue. This subcellular location, taken together with other evidence, suggests that this 43-kDa protein has a role in the cell-to-cell spread of RCMV.

Antibody Specificity↗