Measurement of ultrasound velocity in yolk and blastula of fish embryo in vivo.

An acoustic microscopy method for measuring the velocity of ultrasound in the yolk and blastula of bony fish embryos at early stages of development was proposed. The yolk and blastula were approximated as a sphere and a spherical dome, respectively, consisting of a homogeneous liquid. A theoretical model of ultrasonic wave propagation through a spherical liquid drop located on a solid substrate was developed in the ray approximation. The dependence of the wave propagation time on the speed of sound in the drop, its diameter, and the position of the focus of the ultrasonic transducer has been determined. It was shown that the velocity in the drop can be found by solving the inverse problem by minimizing the discrepancy between the experimental and model spatial distributions of the propagation time, assuming that the velocity in the immersion liquid and the radius of the drop are known. The velocities in the yolk and blastula of the loach (Misgurnus fossilis) embryo at the stage of development of the middle blastula were measured in vivo using a pulsed scanning acoustic microscope operating at a central frequency of 50 MHz. The yolk and blastula radii were determined from ultrasound images of the embryo. Acoustic microscopy measurements conducted with four embryos provide velocities of the acoustic longitudinal wave in the yolk and blastula. They were measured to be 1581 ± 5 m/s and 1525 ± 4 m/s when the temperature of the liquid in the water tank was kept at 22 ± 2 °C.

[Long-term clinical results of surgical treatment in patients with salivary stone disease and ducts deformation of the parotid gland]. / Otdalennye rezul'taty operativnykh vmeshatel'stv u bol'nykh sliunnokamennoi bolezn'iu i protokovymi deformatsiiami okoloushnoi sliunnoi zhelezy.

The authors with the goal of postoperative dynamic control over the results of surgical treatment of patients previously operated for salivary stone disease and various ducts deformations of the parotid salivary glands examined 16 patients with an observation period up to 8 years. It was found that recurrent acute parotitis or recurrence of stone formation was observed in 100% of cases. The authors developed methods of surgical treatment leads to long-term clinical success with no recurrence of the disease.

[Non-destructive ultrasonic technique of enamel thickness measurement].

An ultrasonic technique of enamel thickness measurement has been proposed. In this technique, a thin tray with a hole is placed on the surface of the tooth and the tip of the ultrasonic probe is inserted in this hole to prevent lateral shift of the tip during adjustment of angular position of the probe. Results of the ultrasonic measurements carried out on the extracted teeth with the enamel layer thickness in a range of 1-0.3 mm and the inclination angle up to 0.1 show that the relative thickness measurement error does not exceed ± 2-3%. Typical deviation between the ultrasonic data and the results of the destructive evaluation of the specimens is about ± 0.05 mm.

The effects of analogs of the C-terminal fragment of arginine-vasopressin on the dynamics of development of a conditioned active avoidance response in rats.

This paper reports studies of the effects of original analogs of the C-terminal fragment AVP(6-9), D-MPR and D-MPRG, on the development of a conditioned active avoidance response in rats; agents were given intranasally over a wide range of doses. The most effective does of D-MPR was 0.1 microgram/kg, and the most effective dose of D-MPRG was 0.01 microgram/kg. The tri- and tetrapeptide doses were 10 and 100 times smaller than the dose of arginine-vasopressin used in analogous experimental conditions. The tri- and tetrapeptide accelerated development of the active avoidance conditioned response, affecting both formation of the habit and consolidation of the memory trace. The actions of these peptides were mainly on perception processes, i.e., isolation of the concrete stimulus from the environment, and assessment and remembering of its biological significance.

[The effect of analogs of the C-termination fragment of arginyl vasopressin on the dynamics of the acquisition of an active avoidance conditioned reaction in rats]. / Vliianie analogov C-kontsevogo fragmenta arginilvazopressina na dinamiku vyrabotki uslovnoi reaktsii aktivnogo izbeganiia u krys.

The effect of original analogues of the 6-9 C-terminal AVP fragment, D-MRP and D-MPRG, on the active avoidance behaviour of rats was studied using intranasal administration in a wide range of doses. The dose in 0.1 mcg/kg was the most efficient for D-MPR and 0.01 mcg/kg for D-MPRG, which for the tripeptide was ten times, and for the tetrapeptide hundred times lower than the corresponding dose of AVP used in the similar experiments. The tri- and tetrapeptide were shown to facilitate the active avoidance behaviour affecting both the formation of the reaction and consolidation of memory trace. The peptides mostly affect the perception processes, i.e., the detection of a specific stimulus from the environment, the estimation and memorizing of its biological significance.

[Neurochemical aspects of the cortical-subcortical interrelations after activation of the dopamine system with L-dopa]. / Neirokhimicheskie aspekty korkovo-podkorkovykh vzaimootnoshenii pri aktivirovanii dofaminovoi sistemy s pomoshch'iu L-dofa.

In two groups of Wistar rats differing in horizontal motor activity in an open field, there was a dramatic lowering of that parameter after 2 weeks of administration of L-DOPA in the daily dose 50 mg/kg bw. The lowering in each group turned out different. Interferometric and cytophotometric studies of layers III and IV neurons of the sensorimotor cortex, n. caudatus and n. accumbens, made it possible to detect changes in the area of cytoplasm and neuronal nuclei, in their protein content, in aminopeptidase, glutamate dehydrogenase and glucose 6-phosphate dehydrogenase activity. The intensity and tendencies of the changes varied in both groups animals. It is concluded that excess dopamine produces an effect on the plastic and oxidative types of neuronal metabolism in the indicated structures.

[Effect of vasopressin on changes in the behavioral reactions of rats induced by psychotropic substances]. / Vliianie vazopressina na izmeneniia povedenicheskikh reaktsii u krys, vyzvannye psikhotropnymi veshchestvami.

The effect was studied of arginyl-8-vasopressin (AVP) on changes in rats behavioural reactions, elicited by reserpine, haloperidol, aminazine, amitriptyline or nialamide. It has been shown that AVP administered intraperitoneally in a dose of 0.001 mg/kg, eliminates the deficit of elaboration of conditioned reaction of active avoidance produced by psychotropic drugs, without influencing the motor activity reduction developed after administration of these substances.

[Current concepts of the mechanisms of neurological memory]. / Sovremennye predstavleniia o mekhanizmakh neirologigicheskoi pamiati.

The modern conceptions on the processes which can participate in the neurological memory formation are stated in the review. The biochemical reactions which can join in genesis of various forms of memory according to the duration (minimum, short-time, relatively limited in time, lifelong) are considered. The data on neuropeptide role as well the possibility of participation of immunological mechanisms in traced processes are under discussion.

[The elimination of disorders in the acquisition of a conditioned active avoidance reaction by using the C-termination fragment of lysyl vasopressin]. / Ustranenie narushenii vyrabotki uslovnoi reaktsii aktivnogo izbeganiia C-kontsevym fragmentom lizilvazopressina.

In experiments with male white rats it was shown that 0.001 and 0.01 mg/kg of lysyl vasopressin C-terminal fragment--Pro-Lys-Gly (PLG) being injected intraperitoneally fails to influence the acquisition of active and passive avoidance and also T-maze food rewarded behaviour. The injection of PLG removed by disturbances of active avoidance caused by cyproheptadine and oxytocin. The inhibition of passive avoidance and food-rewarded behaviour was not removed by PLG.

[Evaluation of the effect of arginine vasopressin on the formation of the conditioned reaction of active avoidance in rats]. / Otsenka deistviia arginil-vazopressina na formirovanie uslovnoi reaktsii aktivnogo izbeganiia u krys.

The effect was studied of arginine-vasopressin (AVP) intraperitoneal administration in a doze of 0.001 mg/kg on elaboration of conditioned reaction (CR) of active avoidance in rats. Estimation of reaction dynamics by dynamic delta index allowed to increase the informational value of the experimental data with taking into account the direction of reaction shift and individual characteristic of the animal. AVP improved the elaboration of active avoidance CR, lowered variability of individual learning ability and did not influence the change of the number of intersignal reactions and short-latency escapes in the process of learning. It is suggested that the main site of AVP effect is the animal's reaction to conditioned sound stimulus.

[Effect of hormones of the neurohypophysis on different types of behavioral responses in the rat]. / Deistvie gormonov neirogipofiza na razlichnye tipy povedencheskikh reaktsii u krys.

In experiments on male rats arginyl-vasopressin (AVP), lysyl-vasopressin (LVP) and vasotocin (VT) in doses of 0.005-0.010 mg/kg decreased motor activity and emotional behaviour in the open field test. In a dose of 0.001 mg/kg AVP significantly accelerated the elaboration of active avoidance; oxytocin delayed it, but LVP and VT had no significant influence. AVP also somewhat attenuated the elaboration of passive avoidance. None of the four studied peptides significantly affected the rate of elaboration of conditioned food-rewarded reaction to place.

[Effect of lysyl vasopressin and vasotocin on a disorder of the conditioned avoidance reaction by a serotonin receptor blockader]. / Vliianie lizilvazopressina i vazototsina na narushenie vyrabotki uslovnoi reaktsii izbeganiia blokatorom serotonimovykh retseptorov.

A study was made of the effect of systemic injection of lys8-vasopressin (LVP) and Arg8-vasotocin (AVT) on avoidance reaction in male rats. Both the compounds had no appreciable effect on the rate of the formation. However, in the presence of learning disorders induced by cyproheptadine. LVP completely and AVT partially recovered the normal time course of learning.

[Possible mechanisms of the divergent effects of ACTH4--10 and its analog containing the D-isomer of phenylalanine on behavior]. / Vozmozhnye mekhanizmy raznonapravlennogo deistviia AKTG4--10 i ego analoga, soderzhashchego D-izomer fenilalanina, na povedenie.

The effect of two oligopeptides--ACTG4-10 and hexopeptide met-glu-his-D-phen-lis-L-phen (Dphen-GP) on memorizing the situation and on orienting-investigating reaction was studied in albino rats by the method of elaboration of food-procuring habit in T-maze and by the method of "open field". It was shown that these peptides in a dose of 15 mcg/kg with certain periods of administration, have an opposite effect on maze learning but a similar effect on memorizing in the "open field". ACTG4-10 slightly increases motor activity in the "open field", whereas Dphen-GP decreases it considerably. It is suggested that ACTG4-10 improves the formation of trace processes independently of the sign of reinforcement, whereas Dphen-GP selectively enhances defensive reaction and memorizing, connected with negative reinforcement.

[Role of the orienting and defensive components in the "open field" behavior of white rats]. / Rol' orientirovochnogo i oboronitel'nogo komponentov v povedenii belykh krys v usloviiakh "otkrytogo polia".

Stress effects (of bright light, sound) on the behaviour in the "open field" were studied on male albino rats. It was shown that distribution of motor and vertical activity is close to normal whereas distribution of the number of groomings and defecations considerably differs from it. In a "stressless" situation as compared to a "stressful" one there is an increase in motor and vertical activity and the number of groomings along with a considerable decrease in the number of defecations. In estimating correlation coefficients in pairs between animal's weight and behavioural reaction parameters, the absence of correlation between motor activity and the number of defecations was observed.