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Biomedical subjects

R Polsky-Cynkin

Publications and source records attributed to R Polsky-Cynkin.

7 recordsLinked to original sources
PubMed1985

Use of DNA immobilized on plastic and agarose supports to detect DNA by sandwich hybridization.

Cloned Salmonella DNA, which has been immobilized irreversibly on plastic and agarose solid supports, can form hybrids in both single-layer and "sandwich" hybridization protocols. In single-layer hybridization, 3 micrograms of immobilized DNA bound at least 30 fmol of a specific 800-base DNA sequence (equivalent to 8.5 ng, or the amount of that sequence present in 4 X 10(10) organisms). In a 4-h sandwich hybridization protocol, as little as 14 amol (equivalent to 8 pg, or the amount of that sequence present in 1 X 10(7) organisms) of a 1600-base sequence of DNA could be detected. The methods described should be applicable to use with any set of probes--not just from Salmonella--that fulfill the criteria specified. The ability to perform DNA hybridizations on solid-phase matrices such as those used for immunoassay should bring DNA hybridization into the realm of routine clinical laboratory procedures.

DNA↗
PubMed1983

Use of a solid-state multihead gamma counter in a second-generation system for solid-phase immunoassay.

Simultaneous advances in detector technology and solid-phase separation systems, as well as the availability of powerful desktop computers, have made possible the development of "second-generation" solid-phase immunoassays. These retain the advantages of classical solid phase while significantly accelerating reaction kinetics. Hapten assays--such as for digoxin, thyroxin, and triiodothyronine uptake--in batches of 48 are processed in about 20 min from reagent introduction until hard-copy printout, with minimal operator involvement. The system also functions as a 48-detector gamma counter, capable of counting and reducing data for any 125I-based RIA that can be run in a 12 X 75 mm test tube. System control, data management, and computer screen displays of kinetic data are provided by an unmodified Hewlett Packard HP-87XM computer. User-friendly disc-based software facilitates the creation and storage of counting and data reduction protocols for as many as 30 RIAs from various manufacturers as well as up to 30 of our own assays.

Computers↗
PubMed1976

Stimulation of prostaglandin biosynthesis by vasoactive substances in methylcholanthrene-transformed mouse BALB/3T3.

Prostaglandins E2 and F2alpha are present in the culture medium of methylcholanthrene-transformed mouse BALB/3T3 cells. The production of these prostaglandins is stimulated when the cells are incubated in the presence of serum, arachidonic acid, thrombin, and bradykinin, or if they are mechanically manipulated. Whereas the appearance of prostaglandins resulting from the latter four treatments is complete in several minutes, in the presence of serum the prostaglandin levels are still increasing ever after 2 hours. Stimulation by all of these treatments is additive. Indomethacin inhibits these stimulations, suggesting that the production of prostaglandins results from de novo biosynthesis.

Animals↗
PubMed1976

The effects of hydroquinone, hematin and heme-containing proteins on prostaglandin biosynthesis by methylcholanthrene-transformed mouse BALB/3T3 fibroblasts.

Cultured methylcholanthrene-transformed 3T3 mouse fibroblasts secrete large amounts of prostaglandin into the medium. Prostaglandin biosynthesis by these cells can be stimulated by arachidonic acid and, to a much lesser extent, by glutathione and porphyrin. In the presence of hydroquinone, prostaglandin production is increased; the most striking increases are seen at concentrations that are lethal. Porphyrins, when added to cells in the presence of lethal levels of hydroquinone, inhibit stimulation of prostaglandin E2 synthesis but stimulate the production of prostaglandin F2alpha.

Animals↗