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Biomedical subjects

I Isenberg

Publications and source records attributed to I Isenberg.

48 records · Page 3Linked to original sources
PubMed1970

Binding of polycyclic aromatic hydrocarbons to polyadenylic acid.

A number of polycyclic aromatic hydrocarbons bind to the double-stranded, acid form of polyadenylic acid (poly A). Model building shows that these hydrocarbons may intercalate in the helix, and be well protected from contact with the aqueous medium. Hydrocarbons that are too large to be so protected are found not to bind. A size criterion for the binding of hydrocarbons to poly A therefore exists. This criterion differs from one that was previously found for DNA. The size criteria for DNA and poly A, together, serve as strong evidence for the intercalation model for hydrocarbon complexes.Model-building experiments show that only a small portion of the hydrocarbon need extend into the medium to prevent binding. This finding implies that in two cases (1,2,5,6-dibenzanthracene.poly A and 3,4-benzpyrene.DNA) the structure of the complex is almost completely determined by the size criterion alone.

Adenine Nucleotides↗
PubMed1969

The analysis of fluorescence decay by a method of moments.

The fluorescence decay of the excited state of most biopolymers, and biopolymer conjugates and complexes, is not, in general, a simple exponential. The method of moments is used to establish a means of analyzing such multi-exponential decays. The method is tested by the use of computer simulated data, assuming that the limiting error is determined by noise generated by a pseudorandom number generator. Multi-exponential systems with relatively closely spaced decay constants may be successfully analyzed. The analyses show the requirements, in terms of precision, that data must meet. The results may be used both as an aid in the design of equipment and in the analysis of data subsequently obtained.

Biophysical Phenomena↗
PubMed1965

Quenching of DNA phosphorescence.

Paramagnetic cations quench the phosphorescence of DNA at concentrations well below one ion per DNA phosphate. The order of quenching efficiency is copper, nickel, cobalt, and manganese.

Cobalt↗