PubMed Health⌕ Search

Biomedical subjects

A A Tkachenko

Publications and source records attributed to A A Tkachenko.

At least 19 recordsLinked to original sources
PubMed2005

Ultrasoft x-ray Bremsstrahlung isochromatic spectra from 300-2000 eV electrons on Ar and Kr.

For the first time the bremsstrahlung effect was studied experimentally in the spectral region of 6.5-10 nm with 300-2000 eV electron scattering on Ar and Kr atoms. The isochromatic curves displayed maxima at electron energies of approximately = 0.7 keV (Ar) and approximately =1 keV (Kr); their positions are almost independent of the radiation wavelength in the range studied. These experimental data cannot be treated in the framework of theory based on the first Born approximation. A phenomenological modification of the quasiclassical (soft-photon) approximation is proposed which gives a qualitative treatment of data.

Journal Article↗
PubMed1999

[Sex role identity in persons with paraphilias].

Specificity of sexual role identity was studied in individuals with disorders of sexual drive with focus on the study of individual expression of sexual role signs and correlation between value-regulatory and standard-role components of sex self-consciousness in paraphilias. By means of modified psychologic projective methods, two groups who had committed criminal sex delicts were examined: a group with different variations of paraphilias (69 examinees), a group without any anomalies of sexual drives (57 examinees), a control group (65 healthy men). The data obtained about a divergence of value-regulatory and standard-role components of sexual role self-consciousness indicated disorder of the stage of forming of stable role self-identity at juvenile age and reflected difficulties in interiorization of male sex-role standards in individuals with the disorders of sex drive.

Adolescent↗
PubMed1997

[Interhemispheric EEG coherence in men with abnormal sexual behavior].

Interhemispheric interactions were examined in individuals with abnormal sexual behaviour by means of method of evaluation of coherent EEG properties in symmetric points of two hemispheres in different levels of awakening and in elaboration of cognitive tests related with preferential activation of one of two hemispheres. It was determined that EEG of the individuals who had committed sexual deliquency and had the signs of paraphilia was characterized by diffuse elevation of the degree of interhemispheric coherence in alpha-activity in the state of both passive and active awakening and by its local elevation in theta-activity. The results obtained might testify to the disorders either in cortical-subcortical interactions and in the cortical processes and permitted to suppose the decrease of degree of functional hemispheric lateralization in persons with paraphilias.

Adult↗
PubMed1995

[Monoamine metabolism in different forms of paraphilias].

42 persons which commited crime sexual actions were examined in terms of clinical and neurochemical investigations. The sexual behaviours of 31 patients from this group were associated with sexual inclination pathology--with paraphilia. The patients were divided into 2 groups namely with compulsive form of paraphilia (13 individuals) and without compulsive disturbances (18 patients). Both free and conjugated forms of norepinephrine (NA), dopamine (DA), dihyroxyphenylalanine (DOPA) and dihyroxyphenylacetic acid (DOPAC) were measured in serum and daily urine as well as serotonin concentration was estimated in blood plasma and platelets. The rate of 3H-serotonin uptake into platelets (Vmax) was also investigated. It was determined that Vmax, free and especially conjugated forms of NA, DA, DOPAC levels were significantly higher in patients with compulsive forms of paraphilia. It was supposed that monoamine mechanisms may be operated in psychopathological variations of the crime sexual behaviour.

Biogenic Monoamines↗
PubMed1992

[A comparative evaluation of the biochemical and psychopathological characteristics in subjects with signs of pedophilia].

RIA was employed to examine 54 test subjects who committed sexual crimes with regard to children of tender age. A syndrome of sexual perversions in the form of pedophilia was discovered in 42 persons. Different patients' groups manifested significant differences in the content of hypophyseal and sexual hormones in the blood serum. A significant lowering of testosterone was revealed in persons with heterosexual pedophilia and with pedophilia without any aggressive and sadistic disorders. They also demonstrated a high prolactin content.

Adult↗
PubMed1991

[The clinico-biochemical characteristics of persons with paraphilias and a chromosome anomaly (47, XYY)].

The authors describe the results of a comprehensive examination of 5 persons with chromosomal aberration (47, XYY) manifesting the signs of deviation from normal sexual behavior. The examined were shown to have common dysontogenesis that manifested itself by retardation of the biological basis of sexuality, psychosexual formation together with retardation of the mental processes on the whole. Whatever variants of deviations from normal sexual behavior the common feature was predominance in the libido structure of sadistic aims, that contributed to the revealing of aggressive sexual behavior. Material changes were discovered by radioimmunoassay in the function of the hypothalamohypophyseal and gonadal system in persons with the "YY syndrome". The levels of prolactin and luteinizing hormone along with the LH/FSH ratio appeared significantly elevated. Disorders were also identified in the hypothalamohypophyseal and thyroid system. It is assumed that the discovered changes influence the serotoninergic mechanisms by which aggressive and pathological sexual behavior is formed in such persons.

Gonadal Steroid Hormones↗
PubMed1991

[Clinico-pathogenetic characteristics of exhibitionism].

The author relates the results of ++clinico-psychopathological and sexological studies carried out in 61 men with the signs of exhibitionism. With the nosological qualification of the mental status of exhibitionists being diverse, the four uniform ++clinico-pathogenetic groups were distinguished: with the hypothalamic and temporal syndromes, ++non-processual autism syndromes, and schizophrenic defect. The involvement of biological factors in the genesis of pathological inclination is demonstrated to be of uncertain degree, depending on the classifying with the groups indicated. Heterogeneity dysontogenesis of the psychosexual development was discovered with the aid of sexological examination. At the same time the author proves the common character of the pathogenetic components of exhibitionism, lying in the unity of the constitutional basis for their individual characteristics.

Adolescent↗
PubMed1990

[The level of sex hormones in men with a sexual behavior disorder in the form of exhibitionism].

The paper is concerned with the results of radioimmunological studies reflecting the importance of the function of the hypothalamohypophyseal-gonadal system in 29 men with the signs of organic brain lesions, against whom criminal proceedings were instituted because of exhibitionism. Among the examinees the subgroups with the hypothalamic and temporal syndromes were distinguished. The data obtained were compared to those in 25 mentally normal men and 17 examinees with residual organic brain lesions without sexual behavior abnormalities. The data derived have demonstrated the impairment of the function of the indicated system in the test subjects, associated with sexual behavior impairment in the form of exhibitionism which may form the biological basis for distortion of sexual self-consciousness.

Adolescent↗
PubMed1981

[Mechanism of the antimicrobial action of myeloperoxidase. The role of adsorption of the enzyme on the target cell surface].

Myeloperoxidase (MPO), obtained from the granular fraction of bovine neutrophils at low concentrations (3 nm), exerted antibiotic influence on E. coli. After treatment with the MPO3 - H2O2 - Cl- system the number of living cells in the suspension dropped to 4.7% of the initial value. The preliminary treatment of MPO with antibodies at high concentrations, thus preventing MPO from being adsorbed on the surface of bacterial cells without suppressing its enzymatic catalytic activity, resulted in the considerable decrease of its bactericidal effect. These results suggest that the adsorption of MPO on the surface of target cells is the essential condition of its antimicrobial action.

Adsorption↗
PubMed1980

[Probing the structure of bacterial deoxyribonucleoproteins with exogenous and endogenous nucleases].

During digestion of deoxyribonucleoproteins (DNP) of gram-negative bacteria by micrococcal nuclease and Ca2+, Mg2+-dependent endonuclease in situ regular series fragments-and large nuclease-resistent fragments of DNP were revealed by electrophoresis. The DNP length of the smallest DNP-fragment was tentatively 120-140 base pairs. In investigated bacterial species DNP contained at least two basic proteins which had electrophoretic mobility similar to that of histone H4 of eucaryot. It is suggested that bacterial DNPs have common regular structure.

Bacterial Proteins↗
PubMedDate not supplied

[Effect on glucose on levansucrase synthesis by Gluconobacter oxydans].

The effect of glucose on synthesis of levansucrase was studied with Gluconobacter oxydans L-1. Glucose added to the nutritional medium containing sucrose was found to supress its degradation by G. oxydans L-1. At the same time, the lag phase became shorter. Synthesis of levansucrase was inhibited in the nutritional medium containing glucose while the enzymatic activity increased proportionally to the amount of bacterial biomass in the medium containing sorbitol. Addition of glucose to the nutritional medium containing sorbitol prior to inoculation results in a decrease of the differential rate of levansucrase synthesis. The repressory effect of glucose on the enzyme synthesis manifested itself most distinctly at its addition to the culture in the period of bacterial multiplication with the maximum rate.

Enzyme Repression↗
PubMedDate not supplied

[Principles of the forensic psychiatric assessment of exhibitionism].

Incompetence of the existing approach to forensic psychiatric assessment of exhibitionism as well as the necessity for conducting the analysis of direct manifestations of perverse behaviour are shown. Dissimilar clinical manifestations of this kind of paraphilias are presented and its fixed, compulsive and impulsive variants are described. The necessity for singling out differential forensic psychiatric criteria depending on psychopathologic characteristics of exhibitionism is stressed.

Exhibitionism↗