Relationship between size and eccentricity of receptive fields in the cat cerebral cortex area 21

Sizes of receptive fields (RF) in areas 21, 7, and 19 of the cerebral cortex were measured in cats. No correlation between size of RF and eccentricity (average: R=0.15; p>0.05) was found in area 21, as distinct from areas 7 and 19, where size of RF increased with distance from the center to the periphery (R=0.5; p<0.01 and R=0.9; p<0.0001 respectively). Larger RF were found in the left hemisphere than in the right in field 21; size of RF also decreased and leveled out with a move away from area 21 and towards areas 7 and 19.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 19, No. 2, pp. 233–236, March–April, 1987.     

Two subforms of eukaryotic topoisomerase I. Purification and structure-function relationships.

A new method for isolation of eukaryotic topoisomerase I from calf thymus and from Jurkat-1 cells using HPLC has been developed. The method allows quantitative purification of high molecular weight topo I and two low molecular weight fractions differing by their isoelectric points. It has been suggested that these fractions be characterized as two subforms of the enzyme possessing structural and functional differences. The differences in their specific activities, sensitivity to camptothecin and in their proteolytic digestion maps have been demonstrated for the two enzymes.     

Cystathionase: high-performance liquid chromatography. Molecular cloning in lambda gt11. Nonradioactive immunodetection of fusion protein

A method of purification of rat liver cystathionase by high-performance liquid chromatography (HPLC) utilizing non-ideal gel filtration method is proposed. Resolution factors-flow rate, pH values, ionic strength of the mobile phase-were optimized. Antibodies to the enzyme were purified using an immunosorbent synthesized on the basis of epoxylated Toyopearl-65. Radioimmunoassay and immunoblotting demonstrated antibody monospecificity towards cystathionase. These monospecific antibodies were utilized for detecting enzyme amounts (up to 30 pg) using the avidin-biotin system. Rat cDNA expression library in phage lambda gt11 was screened. The cystathionase cDNA clone was isolated, and the structure of the insert was determined.     

Creation of catalytic antibodies metabolizing organophosphate compounds

Development of new ways of creating catalytic antibodies possessing defined substrate specificity towards artificial substrates has important fundamental and practical aspects. Low immunogenicity combined with high stability of immunoglobulins in the blood stream makes abzymes potent remedies. A good example is the cocaine-hydrolyzing antibody that has successfully passed clinical trials. Creation of an effective antidote against organophosphate compounds, which are very toxic substances, is a very realistic goal. The most promising antidotes are based on cholinesterases. These antidotes are now expensive, and their production methods are inefficient. Recombinant antibodies are widely applied in clinics and have some advantage compared to enzymatic drugs. A new potential abzyme antidote will combine effective catalysis comparable to enzymes with high stability and the ability to switch on effector mechanisms specific for antibodies. Examples of abzymes metabolizing organophosphate substrates are discussed in this review.