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Biomedical subjects

A M Gurvich

Publications and source records attributed to A M Gurvich.

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

The dynamic of thermal fields of the brain of rats in the late post-resuscitation period under stress.

The temperature topography of the cerebral cortex of rats following clinical death and resuscitation was investigated with the technique of thermoencephaloscopy. Complete restoration of the neurological status of the animals was achieved over the course of one to two days. Marked disturbances in the background thermal maps and the thermal reactions of the cerebral hemispheres induced by a stressor were identified in the remote post-resuscitation period (up to two months). A pathological mosaicism of the thermal characteristics was detected under the conditions of relative rest, as were disturbances in the dynamics of the temperature reactions of the brain and in the character of the interhemispheric asymmetries under stress. The individual character of the post-resuscitation pathology which is found both in the baseline thermal maps as well as following a functional load is emphasized. The results of the investigation point to the importance of an individual approach in the rehabilitation therapy of the post-resuscitation illness.

Animals↗
PubMedDate not supplied

[Effects of active behavior in the postresuscitation period on the functional and morphological characteristics of the brain].

Efficacy of prolonged (days 10-60 after resuscitation) regular activation of behavior by labyrinth training of 4-staged food search conditioned reflex is studied in rats subjected to 15-min circulation arrest. This training affected the function of the central nervous system, which manifested by decreased anxiety and a higher activity in the open field test. This functional exercise prevented fall-out of neurons in the fifth layer of hemispheres, of cerebellar Purkinje's cells, and of pyramidal neurons in hippocampal sector CA1. These results support the hypothesis proposed by A. M. Gurvich on the possibility of regulating the postresuscitation recovery of the central nervous system by neurophysiological treatment of the brain.

Animals↗
PubMedDate not supplied

[Sensitometric characteristics of medical roentgenographic and fluorographic films. Sensitivity of the amplifying screens combined with a film].

Factors affecting the degree of sensitivity of roentgenographic and radiofluorographic films and of their combinations with fluorescent screens are considered. A method of films exposure with a roentgenosensitometer permitting it to determine the sensitivity in conditions closely approaching the ones used in practice and corresponding to the minimum of the isoopaque is suggested. A way for determining the sensitivity of films in m2-mJ1 and lx-1-c-1 is indicated. Numerical values for the sensitivity of the films and their combinations with the screens are given. It is shown that with Eef = 38 keV, T = 20 degrees C, exposure time of 0.4--1 sec and optical density 1.00 over general focusing the lower limit of the X-ray RM-1film sensitivity to the light of CaWO4-screens is 38 m2-mJ-1 and of the fluorographic film Pphi-3 to the light of the Zn0-68Cd0-32S--Ag-screens -- 14.6 m2-mJ-1 or 30 lx-1-c-1.

Fluoroscopy↗
PubMedDate not supplied

[The delayed effects of systemic circulatory arrest on the free-radical processes in the brain structures of rats with different types of behavior in the emotional resonance test].

Male Wistar rats with different types of behavior in "emotional resonance" test ("active" and "passive") were studied one week after the global ischemia induced by cardiac arrest. Recovery of some physiological functions as well as free-radical-mediated processes and NO-synthase activity were studied in cerebral structures and blood serum. The "open-field" behavior normalized more rapidly in the "active" rats than in the "passive" ones, though the time course of the neurologic deficit compensation did not differ in these groups. A decrease in superoxide scavenging activity and in the content of 2-thiobarbituric acid-reactive material was revealed in the cerebral structures of both "active" and "passive" rats. Increased levels of free-radical generation in the hippocampus of the "passive" rats and in the cerebellum of the "active" rats were found. Higher NO-synthase activity was demonstrated in the cerebellum of the "passive" rats. Taken together, these data suggest that there are specific patterns of free-radical-mediated processes in the brain of rats with different types of behavior in "emotional resonance" test.

Analysis of Variance↗
PubMedDate not supplied

[Radiation detectors and the problem of radiation loads in roentgenodiagnosis].

The development of new effective roentgenolumonophors, screens, based thereon, and image intensifiers helps reduce the exposure radiation dose in radiography, fluorscopy and fluorography. The effect produced by the characteristics of diverse elements of the radiation dectector on the increase of sensitivity is considered. Numerical values of some characteristics are cited.

Fluoroscopy↗
PubMedDate not supplied

[The dynamics of the brain heat fields of rats in the late postresuscitation period during stress].

By thermoencephaloscopy method the temperature relief of the rats cerebral cortex was studied after the clinical death and reanimation. The rehabilitation of the animals neurological status was completed in 1-2 days. In the remote postresuscitation period (up to 2 months), expressed disturbances were revealed of the background thermomaps and of thermal reactions of the cerebral hemispheres, evoked by the stress influence. Pathologic mosaics of thermal characteristics was revealed in conditions of relative rest and disturbance of dynamics of the brain temperature reactions and the character of interhemispheric asymmetries at stress influence. Individual character is pointed out of postreanimative pathology, which is manifest both in the background thermomaps and after the functional load. The results of the studies suggest the importance of individual approach in rehabilitation therapy of postreanimative disease.

Animals↗
PubMedDate not supplied

[Foundation of the Association of Medical Physicists].

The paper is concerned with foundation of the Association of Medical Physicists under the Physical Society of the USSR. The Association is to unite the efforts of physicists, chemists, mathematicians and engineers working at the medical institutions and engaged in physical problems of medicine and in the design of appropriate instruments, devices, equipment and materials in industry, at the Institutes of the Academy of Sciences, and at higher educational establishments. The functions of medical physicists and their roles in consolidation of the relations between medicine and natural sciences and engineering are discussed.

Interprofessional Relations↗
PubMedDate not supplied

[The indices of rat open-field behavior and the characteristics of the survival and functional recovery of the CNS following circulatory arrest].

In experiments on rats it has been shown that for prognostication of successful reanimation after the clinic death of different duration (5, 10, 15 min) correlative interactions between the parameters of behaviour in the open field before blood circulation cessation are more essential than their absolute values. Highly significant correlation coefficients (0.7 and more) between the majority of behaviour parameters were typical for the group of animals which had survived after a prolonged blood circulation cessation (15 min); for rats rehabilitated after 5- and 10-min cessation of the blood circulation--between the characteristics reflecting, basically, the motor-investigating component of the behaviour. In groups of died animals (independently on the duration of clinic death) correlation profile was restricted to characteristics determining only the character of the motor activity. Particular significance is underlined of emotionally psychic components of the behaviour for complete CNS restoration after a prolonged blood circulation cessation in comparison with the shorter ones.

Animals↗
PubMedDate not supplied

[Changes in the sensitivity of the central nervous system to fenazepam at different stages of the recovery period after systemic circulatory arrest in rats].

Chronic experiments were conducted on rats subjected to 10-minute circulatory arrest to study the effect of intraperitoneal phenazepam (2 mg/kg) injection in various periods after resuscitation on some behavior indices. It was found that the changes in the quantitative (the degree of the effect) and qualitative (the extent of the effect) manifestations of the tranquilizing effect of phenazepam were determined by the different stages of restoration (from 1 to 21 days) after resuscitation. The results provide evidence of a definite stage character in the reactivity of the central nervous system in relation to pharmacological effects after resuscitation and, possibly, may reflect the functional reorganization of the work of the receptor complex and ion conductivity in the postresuscitation period.

Anesthesia↗
PubMedDate not supplied

[The postresuscitation changes in the permeability of the hemato-encephalic barrier and their possible pathogenetic significance].

Experiments were conducted on rats with temporary (10-min) clamping of the thoracic vascular bundle and subsequent resuscitation to study the permeability of the blood-brain barrier (BBB) to plasma albumins and globulins and to blood plasma immunoglobulins in different stages of the postresuscitation period. Mild increase of BBB permeability was detected 3 minutes after the beginning of recirculation. Permeability increased markedly in 24 hours and continued growing by the 72nd hour. At a 1-3-hour interval in recirculation the BBB was closed. The obtained results disclose the mechanisms of the development of autoimmune cerebral disorders in an organism that experienced cardiac arrest and resuscitation.

Animals↗
PubMedDate not supplied

[Luminescent digital radiography].

A review is made of the papers concerned with luminescent digital radiography, a new method for roentgen diagnostic examination based on the use of a luminescent screen which storage energy of ionizing radiation during exposure and liberates it in the form of light flashes (photostimulated luminescence) on screen scanning with a narrow beam of laser radiation. The principal bases of the method, properties of the storage screen and the most important parameters of the unit for luminescent digital radiography are considered. The advantages of the new method are discussed as compared with the methods used before as are prospects for its use.

Humans↗
PubMedDate not supplied

[A comparison of various methods of x-ray sensitometry].

Three methods of roentgen sensimetry have been compared: the wedge method based on using the stepped wedge, the Moscow Radiation and Roentgenology Research Institute method consisting in the time-modulation of the exposure by means of a lead diaphragm and revolving cassette with screens and film, and the method, according to which the dose is modulated by changing the distance from the source of irradiation to the cassette. The exposure conditions have been selected in order to achieve the best coordination of the results obtained by all the three methods. The minimal sensitivity of the combination of the medium amplification screens of ZY-B2A type with film PM-1 is about 1000P-1. For a more complete characteristic of the important properties of the roentgenographic films it is necessary in addition to determining the sensitivity, gamma and medium gradient to measure the parameters determining the graininess of the film and the transmission of the screen light by its emulsion layer.

Technology, Radiologic↗