[Sequencing of low-molecular-weight DNA in blood plasma of irradiated rats].

Extracellular low-molecular-weight DNA in blood of irradiated rats was sequenced for the first time. The screening of sequences in the DDBJ database displayed homology of various parts of the rodent genome. Sequences of low-molecular-weight DNA in rat's plasma are enriched with G/C pairs and long interspersed elements relative to rat genome. DNA sequences in blood of rats irradiated at the doses of 8 and 100 Gy have marked distinctions. Data of sequencing of extracellular DNA from normal humans and with pathology were analyzed. DNA sequences of irradiated rats differ from the human ones by a wealth of long interspersed elements. This new knowledge lays the foundation for development of minimally invasive technologies of diagnosing the probability of pathology and controlling the adaptive resources of people in extreme environments.

[The clinical aspects of occupational sensorineural impairment of hearing of the acoustic origin].

The objective of the present study was to elucidate the specific clinical features of occupational sensorineural impairment of hearing (OSNHI) depending on the origin of this pathology, viz. noise, infrasound and/or their combination. The review of research concerning this problem made it possible to systematize variants of ODNHI based on the clinical signs taking into consideration the influence of these physical factors. Pathophysiological features of the exposure of the organs of hearing to infrasound are described.

[Fundamental and applied aspects of preventing the adverse effects of aviation noise].

In the article, aviation noise is discussed as a harmful physical factor with ecological, hygienic, clinical and social implications. Noise contributes to development of general and occupational pathologies, chronic diseases, and reduction of professional longevity. The present-day knowledge of aviation noise sources and dynamics, and effects on environment, population, and aviation personnel is overviewed, as well as strategies to prevent noise consequences, muffling techniques being the key ones.

[The autonomic system reactivity of airport technical personnel using individual protective devices against noise].

The study covered cardiac rhythm variability and hemodynamic parameters in airfield technical personnel under exposure to aviation noise and with use of individual protective measures against noise. Individual protective means remove unfavorable stressful external effects of noise--that is manifested by more stable parameters of sympathetic nervous system activity.

[The potential of tone audiometry for the determination of the sound-absorbing properties of various materials].

The objective of the present work was to experimentally estimate the potential of the tone audiometry technique for the determination of the sound-absorbing properties of various material. The study included 15 subjects at the age from 19 to 32 years. Their audiological examination was followed by the placement of the 5×7 cm spacer plate from the study material beneath the bone vibrator telephone to determine the bone sound-conduction threshold; no air-marking was undertaken. The sound absorption by the study materials of interest was determined in each octave-band from 250 to 8000 Hz from the difference between the starting audiogram and the audiogram of the material of interest. The study was carried out in three stages: (1) evaluation of sound absorption of each of the five materials, (2) measurement of the same parameter in the combinations of 2--4 layers for increasing sound absorption, and (3) fixation of the bone conduction telephone by the operator's hand (the head-mounted harness was used for the same purpose at stages 1 and 2). The experiments demonstrated that the study of bone sound conduction by means of tone audiometry allows to estimate the sound absorption of various materials. This technique may be applied for the development of a subjective method for the measurement of sound absorption in order to evaluate the acoustic effectiveness of materials that can be used to construct individual protective anti-noise devices.

[The hearing function and vegetative reactions in airport technicians using individual hearing protectors].

The objective of the present study was to evaluate the hearing function in the airport technical personnel and estimate the effectiveness of multicomponent anti-noise hearing protectors used by the specialists engaged in the aircraft maintenance. The tonal threshold audiometry was carried out before and after a shiftwork. The extra-aural effect of noise was assessed from the characteristics of cardiac rhythm variability. The study included two groups of subjects: in one of them (n=8) they used ordinary flight headsets (control) in the other the protection was ensured with the help of multi-insert hearing protectors (n=16). The initial hearing thresholds were found to be increased up to 70 and 60 dB at the frequencies of 4 and 8 kHz respectively. The regression analysis revealed the relationship between these parameters and the duration of aerodrome work experience. Temporary threshold shifts were observed only in the control group. An increase in the tone of the sympathetic nervous system was observed in the control subjects but was absent in the study group. It is concluded that the multi-component hearing protectors employed in the present study are highly efficacious anti-noise devices. The mechanisms of noise-induced hearing loss are discussed.

[The value of low-molecular-weight DNA of blood plasma in the diagnostic of the patological processes of different genesis].

The low-molecular-weight DNA appears in blood plasma of irradiated rats, and its content correlates directly with the irradiation dose. Cloning has shown, that enrichment of low-molecular-weight DNA with G+C content and features of its nucleotide sequences point to its ability to form rather stable nucleosomes. DNA obtained after irradiation of rats with principally different doses 8 and 100 Gy differed not only quantitatively, but also by content of the dinucleotides CpG and CpT; this suggests their origin from different sites of genome. For the first time it has been shown that exposure to low-frequency noise results in an increase of the contents of blood plasma low-molecular-weight DNA. In stroke patients blood concentrations of this DNA increased 3 days after the beginning of the acute period, and dynamics of its excretion differs in ischemic and hemorrhagic forms; in the case of ischemia low-molecular-weight DNA appears in cerebrospinal fluid. The chronic obstructive pulmonary disease in the state of remission is characterized by the decline of the level of low-molecular-weight DNA in the blood plasma unlike in the case of the chronic nonobstructive bronchitis. The clear dependence between formation and special features of the low-molecular-weight DNA fraction in blood plasma makes it possible to consider the low-molecular fraction as an universal index of apoptosis, which allows to distinguish basically different conditions of the body.

[The problems of assessment of the high noise impact on the experts of the Air Force].

Air Force specialists are exposed to high intensity noise levels exceeded the maximum permissible levels. Infrasound as a productive factor in accordance with the general technical requirements (OTT) Air Force-86 is not included in the list of standardized factors. The adverse acoustic environment makes the risk of occupational (sensorineural deafness) and professionally-related diseases of the nervous and cardiovascular systems. The system of physical fitness for military service in the Air Force and serving in the Air Force with high-intensity sources of noise, the system of treatment and preventive measures for adverse effects of noise and the procedure for examination of persons with diseases caused by the influence of noise are needed to be reviewed in accordance with the existing state legislative frameworks.

[Medical and biologic evaluation of individual noise-protection means efficiency].

In laboratory and nature, the authors studied protective properties of experimental models of noise-protection earphones with high acoustic efficiency in broadened frequency range. The article covers expedience of studies at workplaces, including medical and biologic methods that evaluate noise-protection in audible and infra-sound ranges.

[Hygienic estimation of combined influence of noise and infrasound on the organism of military men].

Hygienic estimation of combined influence of noise and infrasound on the organism of military men. Combined influence of noise and infrasound is accompanied by essential increase of risk of development neurosensory deafness and hypertensive illness. At combined influence of noise and infrasound with a maximum of a spectrum in the field of a sound range the probability of development neurosensory deafness will prevail. Thus probability of development of pathology of ear above the values established ISO 1999:1990. In a case if the spectrum maximum is necessary on an infrasonic range the probability of development of a hypertensive illness.

[Means and methods of acoustic protection in aviation: current status and outlook for development].

Analysis of the current status of acoustic protection in aviation shows that despite the material progress in the field, risk of professional pathologies in flying and technical personnel is still high. The situation is dramatized by the lack of effective personal and crew acoustic protectors. The authors speculate on applicability of innovative materials and technologies, ingenious designs of earphones and modular prefabricated demountable structures. Tests of proposed personal protectors demonstrated their competitiveness with foreign analogs. Prospective lines of development, e.g. incorporation of active sound absorption systems in existing passive protectors are discussed.

[Assay of extracellular low-molecular DNA in blood as a diagnostic technique for clinical and experimental studies].

It was shown experimentally that ionizing radiation and low-frequency noise increase the level of extracelular low-molecular DNA in rat's blood plasma. Growth of this parameter has been observed in acute stroke patients at the onset of the disease. Low-molecular DNA assay is proposed for evaluation of the unfavorable effects of physical factors on organism.

[Occupationally mediated morbidity in aviation specialists].

General hygienic evaluation covered workplaces of aviation engineers and technicians and showed that work conditions of these occupations are characterized mainly by exposure to noise and infrasound, that are assigned to hazardous (3.4) and jeopardized (4) classes. Analysis of periodic medical examinations results helped to justify evidence based occupational and occupationally mediated diseases.

[Criteria of noise pathologies in aviation specialists and their prognostic implications].

The paper outlines the criteria of noise pathologies in aviation specialists after extended period of exposure to high-intensity noise and infrared sound. Analysis of morbidity and clinical researches shows prevalence of such pathologies as neurosensory deafness, hypertension and discirculatory encephalopathy. These disorders were correlated with career length.

[Hygienic analysis of conditions of work at the aircraft repair plants and ways to improve the acoustic situation].

Inspection of the conditions of work at aircraft repair plants showed that employees are impacted by a number of harmful in-plant factors including noise, infrasound, kerosene, microclimate and others. Acoustic conditions correspond to harmful (3.2-3.4) or dangerous (4) classes. The general rating of the conditions of work is determined by the degree of noise harmfulness and danger. To reduce the risk of professional pathologies, employees must use personal means of acoustic protection.