Search PubMed⌕ Search

Biomedical subjects

M Copeland

Publications and source records attributed to M Copeland.

25 records · Page 2Linked to original sources
PubMed1980

The prostaglandins of articular cartilage. I. Correlates of prostaglandin activity in a chondrocyte culture system.

Suspensions of aggregated chondrocytes display active prostaglandin (PG) production. Radioimmunoassay of culture media and thin layer chromatographic analysis suggests that PGE2 is the primary PG synthesized. In order of decreasing concentration, the following PG were tentatively identified; PGE greater than PGI greater than PGA + PGB greater than or equal to PGF1+2 greater than TxB. An inverse logarithmic relationship was identified between PG synthesis and cells cultured at densities of 1.5 to 7.5 x 10(6) cells/ml. Little or no change in the PG distribution profile was seen at these high cell densities. Maximum PG synthesis was attained after 36 hours of incubation with persistence of high synthetic levels up to 48 hours. PGE2 production measured at various post-isolation intervals indicated an initial high rate of synthesis during the first 4 hours which decreased with time up to 24 hours. Cartilage explant organ cultures demonstrated a similar level of PG synthesis suggesting minimal effect of matrix on cellular PG production. Indomethacin (5 microgram/ml) inhibited PG synthesis by 70% within 4 hours and 85% after 24 hours of exposure. Arachidonic acid supplementation (10 microM) stimulated PG synthesis by 300%.

Animals↗
PubMed1975

Synthesis and antitumor activity of 2-deamino- and N2-(gamma-hydroxypropyl)actinomycin D.

2-Deamino- and N2-(gamma-hydroxypropyl)actinomycin D were synthesized by modification of the parent actinomycin D molecule at the 2 position of the phenoxazinone moiety. The common intermediate was 2-deamino-2-chloroactinomycin D. Catalytic hydrogenation of this material afforded the 2-deamino derivative while treatment with gamma-hydroxypropylamine yielded the N2-(gamma-hydroxypropyl) derivative. These 2-substituted actinomycin D derivatives were less potent in microbiological assays than the parent compound. Evaluation of activity in vivo against three murine tumor systems indicated that optimal dose levels of 2-deaminoactinomydin D were 50 times greater than toxic dose levels of actinomycin D. N2-(gamma-hydroxyporpyl)actinomycin D exhibited antitumor activity similar to the parent compound.

1-Propanol↗
PubMed1975

Asymmetrical state dependency from temporary septal area dysfunction in rats.

Rats with cannulas implanted in the septal area were conditioned, tested, or both conditioned and tested shortly after intracerebral injection of local anesthetic via the cannulas. A 2 X 2 factorial design was used to determine whether the presumed state of temporary septal area dysfunction, previously shown to produce amnesia, has state-dependent properties. A state-dependent learning effect was observed in the rats both conditioned and tested in the dysfunctional stat remembered the aversive conditioning better than those conditioned in the dysfunctional state but tested in the normal state. Since rats conditioned in the normal state but tested during septal dysfunction did appear to exhibit conditioned fear when tested, the state-dependent effect was asymmetrical. Performance effects of the procaine injection were observed and accounted for in determining the state-dependent nature of temporary septal area dysfunction.

Animals↗