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Biomedical subjects

D A Tyrrell

Publications and source records attributed to D A Tyrrell.

At least 127 records · Page 7Linked to original sources

The Leeuwenhoek Lecture, 1980. Is it a virus?

It was shown many years ago that viruses can cause common cold but it is often forgotten that there were prolonged investigations and disagreements before this was agreed. It wa difficult to detect or propagate any virus in the laboratory and it has taken more than two decades of research to arrive at a reasonably complete list of the viruses that cause colds and related diseases. To do so, new techniques were developed by which these very specialized viruses can be grown and studied. Nevertheless unanswered questions remain on the relation between them and the diseases. This research has required finding answers to several different questions about the viruses and the diseases. The questions cannot all be answered in the same way for all virus infections, and recent research has shown that we can learn a great deal about certain viruses and diseases without answering all of the questions; for instance, the role of rotaviruses in diarrhoea was established though the viruses could not be effectively grown in the laboratory. In the light of these ideas I shall refer to the evidence that mental diseases may be due to virus infections and the recent finding that cerebrospinal fluid from such patients produced a cytopathic effect in tissue cultures that was apparently due to a virus-like agent.

Antigens↗

Toxicity of interferon.

The effects of partially purified human leucocyte interferon (PIF) and of a preparation purified by passage twice through a monoclonal antibody affinity chromatography column (NK21F) were compared with those of a control solution in healhty volunteers. After intramuscular injections both interferon preparations caused rises in pulse rate and body temperature, changes in circulating white cell counts, and various unpleasant symptoms, the most common of which were headache, malaise, and fever. Slightly lower doses of NK21F were given, and this was reflected in lower peak serum concentrations. Mean symptom scores, however, were not lower after NK21F than after PIF. Local inflammatory reactions eight hours after intradermal inoculations of these interferons were similar. Purification of interferon using a monoclonal antibody does not reduce the facets of its activity considered in this study. They are therefore inherent in the leucocyte interferon type selected by the antibody.

Adult↗

Cytopathic effects in cultures inoculated with material from Crohn's disease.

Rectal biopsy homogenates, faecal samples, and leucocyte rich plasma obtained from 39 patients were inoculated into tissue cultures. A non-transmissible cytopathic effect was observed in cultures inoculated with material from patients with Crohn's disease. In a blind study this cytopathic effect was observed in three specimens from three patients with Crohn's disease, in six specimens from four patients with ulcerative colitis, and six specimens from five patients with upper gastrointestinal disease. The cytopathic effect is unlikely to be associated with the bowel diseases tested. These results are also consistent with the failure of others to isolate a virus by the techniques used. With the limited range of techniques used no evidence was obtained to implicate conventional viruses in the pathogenesis of Crohn's disease.

Colitis, Ulcerative↗