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Biomedical subjects

S Dealler

Publications and source records attributed to S Dealler.

At least 19 recordsLinked to original sources

Cerebroventricular infusion of pentosan polysulphate in human variant Creutzfeldt-Jakob disease.

Variant Creutzfeldt-Jakob disease (CJD) is a transmissible spongiform encephalopathy believed to be caused by the bovine spongiform encephalopathy agent, an abnormal isoform of the prion protein (PrP(sc)). At present there is no specific or effective treatment available for any form of CJD. Pentosan polysulphate (PPS), a large polyglycoside molecule with weak heparin-like activity, has been shown to prolong the incubation period of the intracerebral infection when administered to the cerebral ventricles in a rodent scrapie model. PPS also prevents the production of further PrP(sc) in cell culture models. These properties of PPS prompted its cerebroventricular administration in a young man with vCJD. Long-term continuous infusion of PPS at a dose of 11 microg/kg/day for 18 months did not cause drug-related side effects. Follow-up CT scans demonstrated progressive brain atrophy during PPS administration. Further basic and clinical research is needed in order to address the issue of efficacy of PPS in vCJD and in other prion diseases.

Adult↗

MMR and toxicology.

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Autistic Disorder↗

The key must fit: macrophages transport prion infection to the central nervous system and may determine the sites of infection within it.

It is suggested that the agent for transmissible spongiform encephalopathies is transferred from an original peripheral site of infection into the brain by recruited and selected circulating macrophages/monocytes. It is because of this selection that strains of disease appear to be different when infecting separate species, but retain characteristics when infecting a single species.

Animals↗

A matter for debate: the risk of bovine spongiform encephalopathy to humans posed by blood transfusion in the UK.

If human infection with bovine spongiform encephalopathy (BSE) were to occur, donated peripheral blood from humans that might have become infected from eating adequate quantities of food containing BSE should, until evidence is available to the contrary, be assumed to contain the human form of the disease. The chance of disease transfer to a blood recipient in 1995, which might in turn cause clinical disease with an incubation period of 20 years, is calculated. Transfusion is calculated to be a potential cause of a maximum of only 0.2% of clinical cases of Creutzfeldt-Jakob disease (CJD) in the UK population if the BSE epidemic were to spread to humans. Prospective epidemiological techniques would be unlikely to demonstrate any such minor contribution that blood transfusion might make to CJD incidence.

Animals↗

Alkaloidal glycosidase inhibitors (AGIs) as the cause of sporadic scrapie, and the potential treatment of both transmissible spongiform encephalopathies (TSEs) and human immunodeficiency virus (HIV) infection.

AGIs are produced by plants and microorgansims in the environment. They are absorbed from the gut, distributed throughout the body and are concentrated inside cells. AGIs alter the glycan chains of cellular glycoproteins (CGP) during their formation so that the same CGP produced by different clones of cells (and hence with different glycan chains) becomes structurally the same. Prion protein (PrP), a CGP, is rendered indestructable to cellular mechanisms (as PrPi) by the TSE infective process; it is suggested that AGIs could both cause and prevent this by altering the primary structure of PrP. HIV envelope protein, gp120, carries glycan chains that are decided by the clone of the cells by which it is produced. Each cellular clone would be expected to add a specific group of glycan chains, making the gp120 antigenically separate. As HIV infection progresses, infected clone numbers rise, the antigenic diversity of gp120 may rise as would antibody production, trying to keep pace. Antigenically stimulated CD4+ cells carrying HIV genes, increase HIV production with gp120 antigenically different from its stimulant. AGIs prevent the glycan diversity and may prevent the extension of HIV infection.

Alkaloids↗