Rhodopsin resynthesis in rats with hereditary retinal dystrophy

Rhodopsin resynthesis was studied in vivo in the retina and optic cup of two strains of rats with hereditary dystrophy: Campbell albino rats and Hunter rats with pigmented eyes. Wistar and MSU rats, respectively, were used as the controls. The rate of reduction of rhodopsin after its decolorization in the retina in the affected animals was shown to be much slower than in healthy animals and to decrease as the disease developed. In the period of marked morphological changes, only 50% of the decolorized pigment was reduced during 2 h of dark adaptation (the time for complete regeneration of rhodopsin in healthy rats). In Campbell and Hunter rats the breakdown and resynthesis of rhodopsin take place not only in the retina, but also in the layer of fragments of outer segments of the photoreceptors, located between cells of the pigmented epithelium and the retina.Laboratory of the Biochemical Basis of Research, I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Laboratory of Cyctochemistry and Molecular Biology, Institute of Human Morphology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR S. E. Severin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 2, pp. 167–170, February, 1978.     

Models of radiation dispersion in medical laser tomographic system

The prospects for developing a new noninvasive medical diagnostic technique, such as optical (laser) tomography of biological tissues largely depend on the feasibility of designing an adequate mathematical model for the reconstruction of images of the spatial structure of objects that are in the highly scattering medium (HSM). The basic difficulty is that it is necessary to effectively describe the physical properties and the propagation pattern of photons of different types in such a medium. This review considers methods for describing the distribution of laser ultrashort pulses in HSM with particular emphasis on a new nonstationary two-flux model of radiation transfer.     

Interaction mechanism between TiO2 nanostructures and bovine leukemia virus proteins in photoluminescence-based immunosensors

In this research a mechanism of interaction between a semiconducting TiO₂ layer and bovine leukemia virus protein gp51, applied in the design of photoluminescence-based immunosensors, is proposed and discussed. Protein gp51 was adsorbed on the surface of a nanostructured TiO₂ thin film, formed on glass substrates (TiO₂/glass). A photoluminescence (PL) peak shift from 517 nm to 499 nm was observed after modification of the TiO₂/glass by adsorbed gp51 (gp51/TiO₂/glass). After incubation of the gp51/TiO₂/glass in a solution containing anti-gp51, a new structure (anti-gp51/gp51/TiO₂/glass) was formed and the PL peak shifted backwards from 499 nm to 516 nm. The above-mentioned PL shifts are attributed to the variations in the self-trapped exciton energy level, which were induced by the changes of electrostatic interaction between the adsorbed gp51 and the negatively charged TiO₂ surface. The strength of the electric field affecting the photoluminescence centers, was determined from variations between the PL-spectra of TiO₂/glass, gp51/TiO₂/glass and anti-gp51/gp51/TiO₂/glass. The principle of how these electric field variations are induced has been predicted. The highlighted origin of the changes in the photoluminescence spectra of TiO₂ after its protein modification reveals an understanding of the interaction mechanism between TiO₂ and proteins that is the key issue responsible for biosensor performance.

In this research a mechanism of interaction between a semiconducting TiO₂ layer and bovine leukemia virus protein gp51, applied in the design of photoluminescence-based immunosensors, is proposed and discussed.     

Comparison of the clinical and hemodynamic effects of nitroglycerin, isosorbide dinitrate and isosorbide-5-mononitrate in acute myocardial infarction]

One hundred and eighty patients with acute myocardial infarction (MI) were followed up. The patients were divided into 3 groups: (1) those receiving glyceryl trinitrate (GTN) (n = 43); (2) those on isosorbide dinitrate (ISDN) (n = 66); (3) those on isosorbide-5-mononitrate (IS-5-MN) (n = 71). In all the groups, the drugs were given by long-term continuous oligovolumic infusion. Following 24 hours of administration, 66.7, 47.3, and 17.1% increases in infusion rates were required in 74.4, 72.7, and 26.8% of the patients from Groups 1, 2, and 3, respectively. All the agents produced a pronounced antianginal effect and resulted in alleviated acute left ventricular failure. The in-hospital mortality rates were 16.2, 16.7, and 12.7% in Groups 1, 2, and 3, respectively. GTN, ISDN, and IS-5-MN caused adverse effects in 4.7, 18.2, and 2.8% of the patients from Groups 1, 2, and 3, respectively.