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Biomedical subjects

M A Landau

Publications and source records attributed to M A Landau.

17 recordsLinked to original sources
PubMed1989

The optimum placement-site of the electrode in electric pulp testing of the 12 anterior teeth.

The present study of 2,387 recordings of 12 anterior teeth in 53 patients indicates that the incisal edge is the optimal placement-site for the electric pulp tester to determine the lowest response threshold. The results show significant individual variations in the lowest threshold responses of the cervical-third, middle-third, incisal one-third, and incisal edge sites on a tooth, with a confidence level of 99%, according to the analysis of variance. The maxillary teeth gave a higher response threshold than the mandibular teeth and different types of teeth (canines and incisors) had statistically significant different response thresholds. The application of the electric pulp tester to the incisal-edge region with exposed dentin produced the most significant decrease in the threshold response.

Adolescent↗
PubMed1977

Studies of the thermodynamics and nature of interaction between serum albumin and penicillins.

The possibility of a calorimetric determination of the number of homogeneous independent binding sites on the protein molecule surface is presented, together with the possibility of the determination of interaction heat and association constants for the binding of small molecules to one such site. Thermodynamic characteristics of interaction of 10 penicillins and methyl orange with primary and secondary binding sites of bovine serum albumin have been obtained using this technique. The data show that hydrogen bonds between the component parts of the complexes studied are absent. The main contribution to free energy change at forming these complexes is made by hydrophobic interactions. Electrostatic forces are also of some importance, their contribution into the complex formation is more significant in the case of quinacillin and carbenicillin which have an additional charged carboxyl group.

Binding Sites↗
PubMedDate not supplied

[Nonspecific photophysiological immunization].

A hypothesis is suggested on the positive effect of light radiation on the formation of protective immune mechanism related to the photophysiological destruction of porphyrins. References to experimental data are given which illustrate the possibility for existence of such a mechanism.

Bilirubin↗
PubMedDate not supplied

[The geometry of the sugar radicals of nucleic acids].

Geometric flexibility has been analyzed in nucleotides with 46 (deoxyribofuranose) and 74 (ribofuranose) conformers and tentatively (within most stable conformation of five-element ring in nucleic acids) 4 and 8 geometric isomers, respectively. Possible biological role of geometric isomers of deoxyribofuranose during DNA functioning has been discussed.

Animals↗
PubMedDate not supplied

[The computer prognosis of the phenomenon of the superactivity neuropharmacological embryotoxic preparations by using molecular topological parameters and the methods of the sample recognition theory].

Discriminant functions were obtained on the basis of experimental data on the superactivity of synthetic analogues of the natural biogenic amines (26 active and 33 superactive derivatives of benzene and indole), which allow prognostication of the superactivity of embryotoxic compounds with respect to sea urchin embryos on the basis of calculated parameters of the molecules. During reclassification of molecules of the learning sample, the percentage of correct recognition is 73.1 for active, 87.9 for superactive, and 81.4% for the entire data bank. The prognostication capacity of the obtained functions is 73-80%.

Animals↗
PubMedDate not supplied

[Biophysical aspects of emergence and development of pathological conditions].

The molecular mechanisms of rise, development, and correction of some uninfectious illness of ungenetical nature and conception of ligand pathology are analyzed. The influence of molecular geometry change upon the pathology development and biophysical aspects of drugs searching are considered.

Biophysical Phenomena↗
PubMedDate not supplied

[A computer study of the relationship between the value and type of their embryotoxicity and the structure of synthetic analogs of biogenic amines].

We calculated 219 topological, electronic, and steric indices for each of 59 studied embryotoxic benzylalkylamines and indolamines. Statistically significant equations correlating embryotoxicity and five calculated parameters were obtained using the method of step multiple regression. The prognostic power of the equation was 88-90%. Discriminant functions obtained by step discriminant analysis allowed prediction of the superactivity of benzylalkylamines and indolamines with 83-87% probability.

Animals↗