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Biomedical subjects

V V Popov

Publications and source records attributed to V V Popov.

At least 19 recordsLinked to original sources
PubMed1991

Interaural intensity and latency difference in the dolphin's auditory system.

Binaural hearing mechanisms were measured in dolphins (Inia geoffrensis) by recording the auditory nerve evoked response from the body surface. The azimuthal position of a sound source at 10-15 degrees from the longitudinal axis elicited interaural intensity disparity up to 20 dB and interaural latency difference as large as 250 microseconds. The latter was many times greater than the acoustical interaural time delay. This latency difference seems to be caused by the intensity disparity. The latency difference seems to be an effective way of coding of intensity disparity.

Acoustic Stimulation↗
PubMed1991

[10 years' experience of heart valve bioprostheses. Present status and future development].

Long-term results of mitral valve replacement with bioprostheses of three original designs are overviewed. Refinement of the supporting framework design, and of modelling and conservation methodologies has made it possible to improve the survival rates and provided for the absence of specific complications in two groups of patients. Experimental evidence allows for anticipating an increase in the terms of bioprostheses performance.

Adolescent↗
PubMed1990

Location of an acoustic window in dolphins.

Auditory brainstem responses (ABR) to sound clicks from sources in different positions were recorded in dolphins Inia geoffrensis. The position of the acoustic window was determined by measurement of acoustic delays. The acoustic window was found to lie close to the auditory meatus and the bulla rather than on the lower jaw.

Animals↗
PubMed1990

Auditory brain stem responses in characterization of dolphin hearing.

Auditory brain stem responses (ABR) were recorded from the head surface of non-anesthetized and non-relaxed bottle-nosed dolphins, Tursiops truncatus. The region of best ABR recording was shown to be located 6-9 cm caudal to the blowhole. The threshold values were about 1 mPa for noise bursts and -3 dB re 1 mPa for tone bursts of the optimal frequency (80 kHz). The maximum frequency at which ABR could be evoked was 140 kHz. The duration of temporal summation reached 0.5 ms at intensities near the threshold and decreased with an increase in intensity. When the stimuli were paired clicks of the same intensity, the time to complete recovery from the second response was about 5 ms, while that to its 50% recovery was 0.7 ms. When the conditioning click exceeded the testing one in intensity, prolongation of the recovery period was observed. A 40-dB intensity difference led to an approximately 10-fold prolongation of this period.

Acoustic Stimulation↗
PubMed1989

[Treatment of patients with gonarthrosis by intra-articular administration of drugs].

The effectiveness of intra-articular administration of kenalog, hydrocortisone, gordox and polyvinylpyrrolidone to patients with gonarthrosis and concurrent synovitis was studied. Kenalog and hydrocortisone were more effective than placebo, while gordox, polyvinylpyrrolidone and placebo had similar effect. Kenalog and hydrocortisone had nearly the same favourable effect in synovitis. Only one patient treated with gordox had side effects. Signs of synovitis were analysed and its most typical symptoms specified.

Adult↗
PubMed1979

[Cancer of the gallbladder].

Clinical observations in 25 patients with cancer of the gallbladder are described. Tumor of this localization, as a rule, is characterized by a latent course with symptoms of cholelithiasis, chronic cholecystitis, manifested by jaundice and signs of neoplasia only ar later stages. Special attention is given to a frequent association of gallbladder cancer with an acute inflammatory process. The prophylaxis against gallbladder cancer is early surgery for cholelithiasis.

Aged↗
PubMed1977

[Diagnosis and treatment of internal biliary fistulas].

In the paper the diagnostic and therapeutic policy employed in 11 patients with internal biliary fistulas, most frequently caused by cholelithiasis, is analysed. Some aspects of the preoperative diagnosis are eluciadated, and it is concluded that patients with internal biliary fistulas are to be treated surgically: cholecystectomy, suturing of defects in the gastric and intestinal wall, the drainage of bile tracts.

Aged↗
PubMed1976

[Detemination of the hearing characteristics of the dolphin by the evoked potential method].

The evoked potentials were recorded in the dolphin Tursiops truncatus auditory cortex with implanted electrodes. Thresholds of the responses to sounds (clicks, noises and tones) ranged from 10(-2) to 10(-3) Pa. Noises evoked potentials with the lowest threshold of about 1-10(-3) Pa. The evoked responses were elicited both by on and off sound effects as well as by change of the sound intensity or frequency. The thresholds of responses to changes of intensity were about 0.6-0.8 db (7-10%); those of responses to changes of frequency were about 0.25%. The temporal summation could be observed up to 20 msec.

Animals↗