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Biomedical subjects

E Pitt

Publications and source records attributed to E Pitt.

25 records · Page 2Linked to original sources
PubMed1984

Rabbit monoarticular arthritis as a model for intra-articular drug injections. The local action of administered cortisol and alpha-1 proteinase inhibitor.

Monoarticular arthritis in the rabbit has been used to study the effect of intra-articular administration of cortisol-21-phosphate and alpha-1-proteinase inhibitor. The preparations were administered both separately and in combination. All treatments improved parameters associated with joint biochemistry and histopathology, but the greatest effect was found when steroid was combined with anti-proteinase. Cortisol-21-phosphate had both an anti-inflammatory and anti-arthritic action, whereas alpha-1-proteinase inhibitor showed little anti-inflammatory action but had some anti-arthritic effect. Alpha-1-proteinase inhibitor had no anti-inflammatory action against carrageenan induced oedema in the rat, but was anti-arthritic against adjuvant induced arthritis in the rat where it reduced both primary and secondary arthritis.

Acid Phosphatase↗
PubMed1983

The use of corticosteroids encapsulated in erythrocytes in the treatment of adjuvant induced arthritis in the rat.

Corticosteroid esters have been encapsulated into intact erythrocytes and used as an intravenous treatment for adjuvant induced arthritis in the rat. The treatment consisted of injections of the encapsulated steroids with the effects monitored for up to 14 days. On an equivalent weight basis both encapsulated cortisol-21-phosphate and prednisolone-21-sodium hemisuccinate proved superior to the free steroid esters administered in solution by injection.

Acute Disease↗
PubMed1983

Encapsulation of drugs in intact erythrocytes: an intravenous delivery system.

A number of drugs and the plasma antiprotease alpha 1-antitrypsin has been encapsulated in intact erythrocytes after hypotonic swelling, using a technique designed to preserve the viability of the cells. By labelling the cells with fluorescein isothiocyanate it has been shown that the cells survive exceptionally well when returned to the animal's circulation. Cell survival has been demonstrated in the rat, rabbit and guinea-pig. With encapsulation of cortisol-21-phosphate and methotrexate it was found that blood levels of the drug were maintained for a longer period than when the free drug was administered. Cortisol-21-phosphate was hydrolysed enzymatically by acid phosphatase located primarily in the erythrocyte membrane. An in vitro test involving the interaction or erythrocytes with phagocytes was developed to determine the viability or erythrocytes after being subjected to the encapsulation process. Preparations which did not interact with phagocytes survived when returned to the animal's circulation. The encapsulation procedure increased the fragility of the cell membrane compared to that of normal cells as measured by the leakage of haemoglobin after thermal treatment but it was found that encapsulated cortisol-21-phosphate in cells actually stabilized the membrane. The electrical charge on the membrane of encapsulating cells was the same as that of the normal cells. The charge on reformed ghosts was lower than that of normal cells. Reformed ghosts were rapidly removed when introduced into the circulation. The encapsulation procedure and its possible applications are discussed.

Animals↗
PubMedDate not supplied

The challenge of Pneumocystis carinii culture.

Published and unpublished data on the cultivation of P. carinii were reviewed by a panel of investigators convened by the National Institutes of Health. Although several cell culture systems allow propagation of P. carinii for a limited time with modest rates of replication, these have not proved adequate for isolation of P. carinii in sufficient quantity to explore important basic biological investigation. Attempts at cell-free culture have yielded only transient proliferation. Because much of the unsuccessful work on cultivation of the organism has been unpublished, the panel agreed that these data may be useful to other investigators in designing experimental strategies for cultivation. Therefore, the purpose of this report is to make available this information to researchers, lest others unknowingly repeat unsuccessful methods. It is hoped that by documenting the history and the complexities of Pneumocystis culture, renewed interest and efforts will be directed toward this fundamental scientific challenge.

Animals↗