[Electrically enhanced damaged tissues healing. Part I: direct current in bone healing]. / Elektryczne wspomaganie gojenia uszkodzonych tkanek. Czesc I: Prad staly i pulsujacy w leczeniu kosci.

The reasons of investigators' interest of damaged tissues healing with electrical current in concise form are represented by the authors. The nonunions and pseudarthroses healing with direct current through negative polarized electrode is described in this article. Hypothetic biological healing mechanisms (as piezoelectric activity, streaming potentials, electric properties of glycosaminoglycan etc.) are discussed. Technical data of currents and their antibacterial properties are described.

[Electrically enhanced damaged tissues healing. Part II: direct and pulse current in soft tissue healing]. / Elektryczne wspomaganie gojenia uszkodzonych tkanek. Czesc II. Prad staly i pulsujacy w leczeniu tkanek miekkich. Leczenie tkanek pradem zmiennym.

Methodology of soft tissues wounds, ulcers and pressure sores healing with direct current is described by the authors. Results of clinical trials and animal experiments are represented, as well as technical and using data. Electrical properties of damaged tissues (e. i. skin battery, vascular-interstitial closed circuits etc.) and probable electrical healing mechanisms are discussed. Effects of electrical current on batteries are described. Inductive and capacitive coupling of electric and magnetic fields, and high voltage electrostimulation for enhance tissue healing are also described in the article.

[Digital goniometry "Spasmometr GC-2"]. / Goniometr cyfrowy "Spasmometr GC-2".

The review of modern application of goniometric assessment in rehabilitation of patients with movement organs system disorders is done by the authors. The construction and principle of operation of digital goniometer, applied to pendulum testing of lower extremities with pathologic changed muscle tone, are described. An electro-optical transducer transmits the digitized time-dependent function of an angle between the thigh and leg axes of subject via an interface to the special computer programme. The function is registered, some coefficients describing extremity motion in joint are determined and the patient is assigned to the proper rehabilitation group by the composed programme. Normal values of the pendulum test coefficients in the asymptomatic subjects are performed.

[Identity of the occupational medicine physician]. / Tozsamosc lekarza medycyny pracy.

The author identifies three meanings contained in the term "occupational medicine': medical research, the system of health care and a separate medical specialisation. The main interest is focused on the third meaning: occupational medicine as a medical specialisation and thus its basic concepts are discussed and defined. The scope of knowledge and skills as well as the kind of practical activities which endow occupational medicine with features which justify its significance as to be separated from other medical disciplines and to become a medical specialisation are indicated. Effective preventive programmes for the populations at risk of health impairment due to occupational exposure to harmful factors and to unsatisfactory working conditions are mentioned by the author as a basic criterion which distinguishes occupational medicine from other medical disciplines.

Behavioral effects of long-term exposure to magnetic fields in rats.

Male rats and pregnant and nonpregnant female rats of the Wistar strain were sham-exposed or exposed to static (0.49 T) or to extremely low frequency (50 Hz) magnetic fields (0.018 T) 2 h per day for 20 consecutive days. Measures of irritability, exploratory activity, and locomotion were made in that order before and after the 4th, 10th, and 17th 2-h exposures. A reliable decrease in the irritability of rats after repeated exposure to a static or undulating field was found. No significant effects of treatment conditions on open-field behavior and locomotor activity were observed. Pregnancy had no influence on the behavioral end points. These results indicate that irritability of rats may be used as a simple behavioral indicant of mammalian sensitivity to magnetic fields.

Changes in liver and kidney concentration of copper, manganese, cobalt and iron in rats exposed to static and low-frequency (50 Hz) magnetic fields.

The concentration of copper, manganese, cobalt, and iron in the liver and kidneys of fertilized and not-fertilized rats exposed to static and low-frequency magnetic fields has been analysed. Using atomic absorption spectrophotometry, no change in concentration has been observed in pregnant rats after exposure to static field. However, significant changes have been observed in fertilized animal exposed 2 hours daily to low-frequency magnetic fields. Changes in concentration of the above-mentioned metals have also been observed in the kidneys of non-fertilized female rats. It seems possible that alternating magnetic fields may have an influence on biological substances which contain metals and on the metabolism of such substances as well.

The effects of noise on vision efficiency.

The aim of this study was to determine the relationship between intensity, noise duration and non-auditory effect represented by changes both in visual acuity and the near point of accommodation. Changes in vision efficiency determined by a black and white chess board were monitored during and after 1 h exposure to 4 levels of noise: 90 dB-A, 93 dB-A, 96 dB-A or 99 dB-A and 2 h exposure to 96 dB-A. Results indicated that vision impairment can be attributed to a complex relationship between the intensity and the duration of exposure to noise.

The effects of impulse noise on hearing.

Impulse noise is a peculiar type of noise that retains its separate status, both as a physical phenomenon and as an adverse influence exerted upon human recipients. The ongoing research and numerous experiments with animals and industrial populations have not yet fully explained its nature. There are no clear-cut standards of measurement procedures, an impulse evaluation, and no admissible intensity levels. A comprehensive review of both Polish and foreign literature on this subject shows that the following features have the most traumatizing effect on the hearing organs: peak value, impulse duration rate, spectrum composition, repetition frequency, equivalent energy level, and a total number of impulses.

Efficiency of ear protectors in laboratory and real life tests.

The effectiveness of ten different ear-protectors (6 types of earmuffs and 4 types of earplugs) has been tested under laboratory conditions and in the real occupational environment. Three methods were used: (1) physical, utilizing a dummy head; (2) subjective, real-ear, executed on trained human subjects; (3) subjective, measuring TTS2 resulting from occupational, one-workday exposure. It could be shown that the ear protection efficiency ascertained on the basis of TTS2 measurements on workers exposed to noise in their occupational environment is, in nearly all cases, smaller than the efficiency expected, taking into account the sound damping of the same protectors, tested under laboratory conditions, using the physical or real-ear method. Measurements of TTS2 were found to give the best data needed to define the protectors' efficiency, since they include, simultaneously, the impact of various environmental factors, the subjective reactiveness, the nature of the professional task and the acoustical features of the protector used. Therefore this method enables the estimation of the real protection given to workers with a risk of noise-induced hearing loss.

[Evaluation of the optical properties of video display terminals]. / Ocena optycznych wlaciwosci monitorów ekranowych.

Video display terminals (VDTs) pose to these operating then professionally risks resulting from optical properties of the screen, lighting conditions and organization of VDT workplaces. The latest Polish VDTs have been tested to determine their ultraviolet and infrared radiation, screen luminance depth and light reflection factors of the casing, key-buttons and documents serving as information sources. The ultraviolet and infrared radiation did not reach a health-hazardous level, however the light reflection factors were highly differentiated and showed unsuitable distribution inside the operator's visual field; the luminance pulsation of the screen exhibits a considerable depth. The findings promoted defining some rules of the proper use of VDTs.

Isolated and combined effects of prolonged exposures to noise and whole-body vibration on hearing, vision and strain.

This study was carried out in order: (1) to examine the effects of isolated and combined prolonged exposures to noise and whole-body vibration on hearing, vision and subjectively experienced strain, and (2) to check the combined effects with repeated exposures. Six male subjects were exposed twice to noise (N) at 92 dBA, whole-body vibration (V) in the Z-axis at 4 Hz and 1.0 ms-2 rms, and noise and vibration (NV) for 90 min with each condition. Temporary threshold shifts of hearing (TTS) and their integrals (ITTS) were measured at 4, 6, 10, and 12 kHz. Visual acuity was examined by means of a very sensitive test. Cross-modality matching (CMM) of the handgrip force was used to judge the subjectively experienced strain. NV induced a clear tendency of higher TTS and ITTS than N, with several significant differences most pronounced at 10 kHz. With repeated exposures, the effect of NV decreased, while the reactions to N and V remained unchanged. The individual reactions to NV differed. The influence of the duration of exposures on vision depended on the condition; N caused time-dependent changes, whereas V did not. CMM-data increased with the duration of the exposure during V and NV. N was generally judged to be more straining than V; NV caused higher strain than V during the first 30 min of exposure only. Correlations between different effects suggest certain links between them. Additionally, less motivation--daily obtained by a questionnaire--often correlated with higher ITTS during N and NV. The results also illustrate the combined effects on the individual susceptibility, repetition of exposure, the kind of response, and, possibly, the actual psychic state.

High-frequency-noise-induced hearing loss: a field study on the role of intensity level and accumulated noise dose.

Based on audiometric tests in the range of 10 to 20 kHz, of 106 ultrasound operators, as well as on measurements of high-frequency noise, the problem of safety limits for high-frequency noise exposure was investigated. Analyzing the relation between noise levels of 1/3 octave bands at center frequencies of 10, 12.5 and 16 kHz and the accumulated noise dose on the one hand, and changes of hearing at 10 to 12, 11 to 13 and 14 to 16 kHz respectively, on the other hand, a harmless level up to 80 dB and a harmless noise dose up to 1 unit for people not older than 40 years have been found. For older people this level and this noise dose can be dangerous.

Dynamics of high-frequency hearing loss of operators of industrial ultrasonic devices.

This investigation was aimed at elucidating the dynamics of hearing loss in the range of 500 Hz to 20 kHz of 26 Ultrasonic (Uls)-operators exposed to high-frequency noise exceeding known hygienic limits. Results of audiometric tests performed twice, before and after a period of three years, were compared. The determined hearing-threshold-shift in the range of 500 Hz to 13 kHz could be explained as the effect of aging, whereas in the range of 13 to 17 kHz the stated mean threshold elevation of 2-5 dB, beyond the hearing loss connected with aging within three years, is the consequence of high-frequency noise exposure. On this basis the dynamics of high-frequency hearing loss of 1 dB/year in the case of continued exposure to high-frequency noise could be calculated. Apart from the observed threshold elevation, the fraction of ears responding to acoustic stimuli at the highest frequencies decreases by about 10% with frequency increase of 1 kHz in the range of 13 to 19 kHz. This indicates that the hearing organ is more susceptible to high-frequency noise at the highest hearing frequencies.

A silent allele for red cell acid phosphatase in a Polish family.

A silent allele of red cell acid phosphatase was found in three generations of a Polish family. The phosphatase levels of 4 family members were about half the normal value.

[Ototoxic factors requiring consideration in the diagnosis of occupational hearing loss]. / Czynniki ototoksyczne wymagajace uwzglednienia w dniagnostyce zawodowego uszkodzenia sluchu.

In the practice of diagnosing occupational deafness resulting from noise effects of factors determining workers' hearing, such as living conditions, working conditions, nutritional and other habits, diseases and their therapy, are often neglected. Discussed in the paper are the significance and ototoxic effects of such factors as: aminoglycoside antibiotics, diuretics, salicylic acid derivatives, fenacetin, quinine, fluorine compounds, cytotoxic drugs, chemical compounds other than drugs (carbon monoxide, carbon disulphide, lead, organic solvents), ethyl alcohol, diseases (abdominal typhus, bacillary dysentery, diphtheria, brucellosis, epidemic parotiditis, poliomyelitis, rubella, aural shingles, syphilis, diabetes mellitus, chronic renopathies, hypothyroidism, serologic conflict, pigmentary retinitis). Exposure to intense noise is more and more frequently juxtaposed with the impact of the mentioned factors. If industrial physicians get aware of this association the prevention of deafness and reliability of treatment may be largely promoted.

High-frequency hearing risk of operators of industrial ultrasonic devices.

Sound and ultrasound emitted by industrial ultrasonic (Uls) devices exceed the known proposed hygienic limits, especially for frequencies 10-20 kHz. The consequence of this may be a negative influence of this energy on the auditory function in the high-frequency hearing range. To determine the hearing risk to Uls operators, an adequate method for testing the hearing threshold from 10-20 kHz has been developed. In order to get reference values, 189 non-exposed persons were tested. On this basis, the hearing thresholds of 55 operators for frequencies 500-20,000 Hz were evaluated. In addition to threshold elevations in the range 10-20 kHz, a decreasing number of subjects responding to stimuli at the highest audible frequencies was observed. The threshold shift at 10-20 kHz of subjects exposed to sound and ultrasound emitted by Uls-devices depends upon the physical parameters of the sound spectrum, time on the job and daily exposure time. No abnormalities were found in the hearing range 500-8000 Hz.