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Biomedical subjects

D V Davydov

Publications and source records attributed to D V Davydov.

15 recordsLinked to original sources
PubMed2005

[Domestic 1.44 mcm Nd:YAG laser in combined treatment of dacryocystitis complicated by abscess formation].

We have treated 12 patients with acute dacryocystitis complicated by abscess formation. All the patients were examined by an ophthalmologist and otolaryngologist. The patients received intravenous antibiotics followed by Nd:YAG laser dacryocystorhinostomy via transcanalicular approach under the endonasal endoscopic control. The treatment resulted in resolution of symptoms and signs of acute dacryocystitis complicated by abscess formation in all the patients. No recurrence of acute dacryocystitis occurred during the median follow-up period of 11 months. Ostium patency defined as the absence of epiphora and observation of irrigated lacrimal fluorescein at the ostium was achieved in 9 patients. Epiphora recurred in 3 cases. Use of Nd:YAG laser reduces the duration of the operation and provides maximal functional and cosmetic results.

Abscess↗
PubMedDate not supplied

Visual evoked potentials in humans during recognition of emotional facial expressions.

Visual evoked potentials were recorded from the occipital, parietal, central, frontal, and posterior temporal areas of the cortex during recognition of emotionally positive, negative and neutral facial expressions and during passive observation in 22 right-handed healthy subjects. These studies showed that in the posterior temporal areas, the latencies of the N90, P150, and N180 waves of potentials evoked by faces with emotionally negative expressions were significantly shorter than those evoked by other types of facial stimuli. Differences were seen both on recognition and during passive observation. Correct recognition involved both hemispheres and was characterized by high levels of interhemisphere temporal correlation of the processes occurring during the development of the P150 wave in the posterior temporal and the N180 wave in the frontal parts of the cortex. The possible relationship of these data to primary subthreshold recognition of facial expressions in the posterior temporal fields of the cortex is discussed, as is the role of the frontal cortex in completing this process and in taking the correct decision about the nature of the image.

Adult↗
PubMedDate not supplied

[Recognition of joy, anger, and fear by face expression in humans].

Behavioral and neurophysiological characteristics of a visual recognition of emotions of joy, anger, and fear were studied in 9 young healthy men and 10 women. It was shown that these emotions were identified by subjects with different rate and accuracy; significant gender differences in recognition of anger and fear were found. Recording of visual evoked potentials (VEP) from the occipital (O1/2), medial temporal (T3/4), inferior temporal (T5/6), and frontal (F3/4) areas revealed differences (related with the type of emotion) in the latencies of P150, N180, P250, and N350 waves and in the amplitude of VEP components with the latencies longer than 250 ms. These differences were maximally expressed in T3/4 derivation. The subjects could be divided in two groups. The first group was characterized by increased VEP latencies and higher amplitudes of VEP components later than 250 ms in response to anger (in comparison with other types of emotions). These phenomena were observed in all the derivations but were most pronounced in T3/4. In the second group, only late P250 and N350 components had shorter latencies during recognition of fear. VEP amplitude variations related with the type of emotions were insignificant and were recorded in the occipital and frontal areas. The two groups of subjects also differed in psychoemotional personality characteristics. It is suggested that primary recognition of facial expression takes place in the temporal cortical areas. A possible correlation of electrophysiological indices of emotion recognition with personality traits is discussed.

Adult↗
PubMedDate not supplied

[Hemispheric asymmetry of visual evoked potentials during human recognition of facial emotional expressions].

Visual evoked potentials (VEP) in standard 16 EEG derivations were recorded in 26 young men and 20 women during recognition of facial emotional expressions and geometric figures. The stimuli were presented on a computer screen in the center of the visual field or randomly in the right or left vision hemifields. Peak VEP latency and mean amplitude in 50-ms epochs were measured; spatiotemporal VEP dynamics was analyzed in a series of topographic maps. The right hemisphere was shown to be more important in processing emotional faces. The character of the asymmetry was dynamic: at earlier stages of emotion processing the electrical activity was higher in the right inferior temporal region compared to the left symmetrical site. Later on the activity was higher in the right frontal and central areas. The dynamic mapping of "face-selective" component N180 of VEPs revealed the onset of activation over the right frontal areas that was followed by the fast activation of symmetrical left zones. Notably, this dynamics didn't correlate with the hemifield of stimuli exposition. The degree of asymmetry was lower during presentation of figures, especially in the inferior temporal and frontal regions. The prominent asymmetry of information processes in the inferior temporal and frontal areas was suggested to be specific for recognition of facial expression.

Adolescent↗
PubMedDate not supplied

[The prevention of a pressor reaction to tracheal intubation in patients with aneurysms of the cerebral vessels. A comparative study of 7 methods].

A comparative study of seven techniques preventing pressor reactions to tracheal intubation (profound barbiturate anesthesia, conventional clinical doses of fentanyl, intravenous lidocaine, pentamine, glycerol trinitrate, sodium nitroprusside and magnesium sulfate) has been conducted in 75 patients with arterial aneurysms and arteriovenous malformations in brain vessels. The best preventive effect was observed with the use of glycerol trinitrate and conventional clinical doses of fentanyl. However, none of the above techniques could completely prevent pressor reactions to intubation.

Anesthesia, Endotracheal↗
PubMedDate not supplied

[The anesthesiological support for children in extracorporeal lithotripsy on the Urat-P apparatus].

The Urat-P lithotriptor made in this country was employed for remote lithotripsy (RLT) in 94 children with urolithiasis. Altogether 132 sessions were conducted. In 120 cases the concrement disintegration progressed in a sparing regimen (impulse duration 0.3-0.4 ms, shock wave energy 5-8 J). In the rest 12 cases there were additional hard impulses (0.5-0.6 ms, the energy 10-12 J). Anesthesiological and transfusiological problems are considered. It is shown that choice of anesthesiological defense is based on the clinical form of the disease, the concrement size, the child's age. Intubation anesthesia with artificial pulmonary ventilation is indicated for young children (under 5). Intravenous balanced anesthesia under normal respiration accompanies RLT in large coral calculi treated in senior children (6-14 years of age). Single stones (up to 1.5 sm) in them are managed under local infiltration anesthesia. It is stated that a valid choice of anesthesia and transfusion therapy warrants favourable conditions for RLT sessions, adverse effects of the impulses on the renal parenchyma and adjacent tissues lessen facilitating the fragments elimination and reducing the number of complications in the postoperative period.

Adolescent↗
PubMedDate not supplied

[Prevention of pressor reaction to tracheal intubation in patients with cerebral aneurysms: fentanyl and nitroglycerin combination].

The authors analyze the clinical efficacy of a combined method for the prevention of pressor reaction to laryngoscopy and tracheal intubation, based on the combination of common clinical doses of fentanyl (4 micrograms/kg b. m.) and intravenous infusion of nitroglycerin solution in 26 patients with brain vessel aneurysms. This method effectively prevented the dangerous rise of arterial pressure during laryngoscopy and tracheal intubation.

Adolescent↗
PubMedDate not supplied

[Changes in the cardiac rhythm in response to acoustic stimuli in subjects with a seasonal affective disorder].

Groups of depressed patients and normal controls were exposed to series of tones of low (75 dB) and high (105 dB) intensity. The initial component (averaged heart rate in 5 s post-stimulus interval) of cardiac reactions to the weak stimuli was decelerative. Depressed patients tended to have more decelerative reactions than controls. In depressed patients there was habituation across trial blocks. The first component of responses to the loud stimuli was predominantly accelerative in both groups. The later phase of the heart rate responses (averaged in the second 5 s post-stimulus interval) was predominantly accelerative in controls and decelerative in patients for both intensities. Characteristic features of orienting and defensive components of the cardiac reactions in winter depressions are discussed.

Acoustic Stimulation↗
PubMedDate not supplied

[Human visual evoked potentials during the recognition of facial emotional expression].

Visual evoked potentials (VEPs) were recorded in 22 right-handed healthy subjects in the occipital, parietal, central, frontal and posterotemporal cortical areas during recognition and passive viewing of positive, negative, and neutral emotional facial expression. Peak latencies of N90, P150, and N180 VEP components appeared to be significantly shorter in response to the negative emotional expression than during administration of other facial stimuli. The differences were observed both during active recognition and passive viewing. Correct recognition was characterized by involvement of both hemispheres and high level of interhemispheric correlation between the peak latencies of P150 in the posterotemporal and of N180 in the frontal areas. It is suggested that the facial expressions are primarily recognized at the subthreshold level with participation of the posterotemporal areas. The role of the frontal areas is discussed in the completion of this process and making the correct decision about the image.

Adult↗