Search PubMed⌕ Search

Biomedical subjects

P Sagar

Publications and source records attributed to P Sagar.

At least 55 records · Page 3Linked to original sources

Comparison of in vitro demyelination and cytotoxicity of humoral factors in multiple sclerosis and other neurological diseases.

The distribution and nature of serum factors causing in vitro demyelination and glial lysis were investigated in multiple sclerosis (MS), other neurological diseases (OND), ill control and control groups. MS sera were unique in affecting only CNS myelin and glia whereas stroke and Guillain-Barré syndrome (GBS) sera brought changes to both CNS and PNS tissue. Through both visual scoring of myelin damage and the quantitative measurement of radiolabel release from cerebellar cultures, it was evident that the MS and OND groups have similar myelino- and cytotoxic effects. This may reflect MS and OND sera sharing similar humoral factors. 74% MS, 68% OND and 22% of control scores were above a score threshold designed to exclude culture handling trauma effects. When classified by their current disease state MS patients with severe and mild disease yielded higher in vitro scores than did those with moderate disease who comprised an older age group. No other clinical features of MS patients gave any association with in vitro serum effects. The rare demonstration of bound Fab IgG in cultures after MS serum tests indicates that immune mechanisms are unlikely to make a large contribution to serum-induced demyelination and cellular change in vitro.

Central Nervous System Diseases↗

Correlation of encystment and division in Schizopyrenus russelli.

Schizopyrenus russelli, a free-living soil ameba, grows and encysts in the presence of bacteria. The encystment occurs with decline in the division rate. This is accompanied by incorporation of [U-14C] glucose into cyst cellulose. The degree of multiplication (but not of encystment) is a function of bacterial concentration. Berenil, a trypanocidal drug, while allowing excystment, completely inhibited multiplication of emerged amebae and their encystment. Addition of this drug after 24 hr, when amebae had gone into a phase of active division failed to check encystment, although it still inhibited further multiplication of the amebae. The findings suggest that a phase of cell division may be a prerequisite for encystment.

Amoeba↗

Correlation of encystment and Division in Schizopyrenus russelli.

Schizopyrenus russelli, a free-living soil ameba, grows and encysts in the presence of bacteria. The encystment occurs with decline in the division rate. This is accompanied by incorporation of [U-14C] glucose into cyst cellulose. The degree of multiplication (but not of encystment) is a function of bacterial concentration. Berenil, a trypanocidal drug, while allowing excystment, completely inhibited multiplication of emerged amebae and their encystment. Addition of this drug after 24 hr, when amebae had gone into a phase of active division failed to check encystment, although it still inhibited further multiplication of the amebae. The findings suggest that a phase of cell division may be a prerequisite for encystment.

Animals↗