The development of a short incubation model of scrapie (strain 263K), in golden hamsters has added impetus to the purification of the infectious agent. Our own attempts have been based on methods pioneered by Millson and developed by Prusiner. We present here results indicating that a purification factor of up to 10(4) with respect to protein may now be possible. Fractions from brain with high infectivity had a sedimentation range of 70-300S and contained an abundance of fibrils closely similar to the scrapie-associated fibrils (SAF) discovered by Merz et al.. Material of molecular weight (Mr) 26,000, which is probably protein, appears to be a major constituent of the fibrils. The association between infectivity and fibrils raises two possibilities: the fibrils are an infectious form of the scrapie agent or they are a pathological response to scrapie infection.

Animals↗

PubMedDate not supplied

Chemotherapy- and radiotherapy-induced cytologic alterations in the sputum of patients with inoperable lung carcinoma. Role in follow-up.

OBJECTIVE: To define the light microscopic cytologic changes due to chemotherapy (CT) and/or radiotherapy (RT); to evaluate the differentiation of those changes according to treatment; to find out whether a relation exists between treatment type and its duration and the cytologic findings; and to determine the role of sputum cytology in evaluating efficacy of treatment and follow-up in patients with inoperable lung cancer of various histology. STUDY DESIGN: A total of 1,605 periodic sputum samples from 80 cases of lung cancer obtained during treatment and follow-up were prospectively examined cytologically. The relationship of treatment type and duration to qualitative and semiquantitative data and the definability of the response to treatment as well as the relationship of progression-free survival (PFS) and total survival (TS) rates with cytologic data were evaluated. RESULTS: The majority of therapy-induced cellular changes were in the nucleus and were directly related to the duration of treatment. An increase in minimally affected tumor cells, tumor cells that lost their pathologic features and necrotic cell debris were good indicators of therapeutic efficacy. Cytologic changes did not reflect PFS and TS rates. CONCLUSION: Although light microscopic cytologic changes cannot be attributed objectively to either RT or CT, therapeutic efficacy is shown in follow-up sputum cytology, which can be used in monitoring and planning additional therapy or other therapeutic options in lung cancer patients.

Carcinoma↗