Myelokaryocyte mitotic activity during microwave irradiation (2375 MHz)

Changes in mitotic activity of myelocaryocytes exposed to super-high frequency field (2375 MHz) of 10, 50 and 500 microW/cm2 for a month show the influence of this factor on the DNA synthesis, premitotic processes and cell reproduction biorhythms depending on the radiation intensity.     

Effect of low intensity pulse-modulated electromagnetic radiation on activity of alkaline phosphatase in blood serum

The change in alkaline phosphotase activity in vitro with frequencies modulation at low intensity of pulse-modulated electromagnetic radiation was experimentally shown (EMR, 2375 MHz, intensity: 0.8, 8.0; 40.0 microW/cm2; range modulation: 30-310 Hz; time of interaction: 1-3 min). Revealed effects could be regarded as an evidence of informative character of interaction of modulated EMR.     

Protective effects of luteolin on rat testis following exposure to 900 MHz electromagnetic field

Increasing cell phone use calls for clarification of the consequences of long term exposure to electromagnetic fields (EMF). We investigated the effects of EMF on the testes of 12-week-old rats as well as possible protective effects of luteolin on testis tissue. Twenty-four Wistar albino rats were randomly divided into four groups: control, EMF, luteolin, and EMF + luteolin. The number of Leydig cells, primary spermatocytes and spermatids were reduced in the EMF group compared to the control group. In the EMF + luteolin group, the number of Leydig cells, primary spermatocytes and spermatids was significantly greater than the EMF group. We found an increase in superoxide dismutase (SOD) activity in the EMF group compared to the control group. In the EMF group, we found decreased wet weight of testes and serum testosterone levels compared to the control group. Decreased SOD enzyme activity, and increased serum testosterone levels and weight of the testes were observed in the EMF + luteolin group compared to the EMF group. EMF also affected sperm morphology. We found that in rat testis repeated exposure to 900 MHz EMF caused changes in testicular tissue and that the antioxidant, luteolin, substantially reduced the deleterious effects of EMF.     

Changes in mast cells after their exposure to constant electromagnetic field

By means of luminescent histochemistry effect of a constant magnetic field with induction 60 mTl (exposition for 2, 6, 36 h and 7 days) has been studied in order to reveal contents of catecholamines in mesenteric mast cells and in the intestinal mesentery cells in 50 white Wistar rats. In 2-6 h specific luminescence of the mast cells increases, however, at prolongation of the exposure up to 30 h metabolism of catecholamines in the mast cells is inhibited noticeably++ (luminescence disappears). In 8 days amount of the mast cells and specific luminescence of catecholamines decrease. The essential shifts revealed in the system of the mast cells of the mammalian should be taken into consideration in the magnetic-therapeutic practice. Close spatial relations between the mast cells and the mesenteric adrenergic terminals have been elucidated, demonstrating their morphofunctional interconnection.     

Measurement of serum bone-specific alkaline phosphatase activity in cynomolgus macaques

Serum levels of bone-specific alkaline phosphatase activity (B-ALP) in cynomolgus monkeys were evaluated as an index of elevated bone turnover following ovariectomy. The enzyme immunoassay 96-well microtiter plate B-ALP assay, developed by Metra Biosystems (Mountain View, CA) for human use, was employed and compared with a standard automated assay measuring total serum levels of alkaline phosphatase activity (T-ALP). The B-ALP assay was first validated for use in these monkeys. Ovariectomy led to increased bone turnover as indicated by approximately 2-fold higher activity in both assays and this elevation was inhibited by daily estradiol administration. Although both assays provided generally similar results, several monkeys were observed to have greatly elevated values of T-ALP but not B-ALP. This discrepancy is believed to result from high levels of the liver isoform of alkaline phosphatase in monkeys with hepatic dysfunction, which are not detected by the B-ALP assay.     

Biological effects of exposure to high frequency electromagnetics on rabbits and guinea pigs]

To investigate the biological effects of exposure to feeble high frequency electromagnetism, skin surface temperature, blood vessel (arterioles and venules) diameter were examined, using infrared thermography, a laser doppler flowmeter, and a video microscope, respectively, in the ear of rabbits. After exposing the ear of rabbits to high frequency electromagnetism value of 9 MHz for 15 minutes, continued rising of local temperature was demonstrated. Though dilatation of arterioles was not seen. In addition, venules tended to dilate and blood flow also to increase, and microcirculation was accelerated at the site where electromagnetism was exposed. Hazardous effects of long term exposures of high frequency electromagnetism (9 MHz for 30 days, 8 hours/day) on guinea pigs were not observed in their behavior, food consumption, body and organ weights, hematological and biochemical values, macroscopic and microscopic findings on autopsy.     

Health and safety implications of exposure to electromagnetic fields in the frequency range 300 Hz to 10 MHz.

An international seminar on health effects of exposure to electromagnetic fields (EMF) in the frequency range from 300 Hz to 10 MHz (referred to as the Intermediate Frequency (IF) range) was held in Maastricht, Netherlands, on 7-8 June 1999. The seminar, organized under the International EMF Project, was sponsored jointly by the World Health Organization (WHO), the International Commission on Non-Ionizing Radiation Protection (ICNIRP), and the Government of the Netherlands. This report does not attempt to summarize all of the material presented at the conference, but focuses on sources of exposure, biophysical and dosimetric considerations pertinent to extrapolating biological data from other frequency ranges to IF and identifies potential health concerns and needs for developing exposure guidelines. This paper is based on presentations at the conference and reports of working groups consisting of the speakers and other experts. It concludes with recommendations for further research aimed at improving health risk assessments in this frequency range.     

Changes of alkaline phosphatase activity in response to different stressors in planarian Dugesia japonica

The aims of this work are to provide some properties of alkaline phosphatase (ALP) in the planarian Dugesia japonica and detect its activity in response to different stressors, as well as to introduce renatured SDS-PAGE to study enzyme activity in planarians. Our results indicate that ALPs in planarians are mainly membrane-bound form, identified as three mainly enzyme-bands (approximately MW 260 kD, 180 kD, 160 kD, respectively). Under our experimental conditions, ALPs activity had no apparent changes in response to low concentration of Hg²⁺ (25 μg L^?1) and Pb²⁺ (125 μg L^?1, 250 μg L^?1) exposure, but were severely inhibited in response to high concentration of Hg²⁺ (50 μg L^?1, 150 μg L^?1, 300 μg L^?1) and Pb²⁺ (500 μg L^?1, 1000 μg L^?1) exposure. Mild heat shock (25°C for 2 days) elevated ALP activity, but severely heat shock (25°C for 2 days, followed by 30°C for 2 days and 32°C for 2 days) inactivated ALP activity. Interestingly, ALP and other cytosolic phosphatases (MW from ～45 kD to ～60 kD) activity increased noticeably during the early stage of planarians regeneration, which may be involved in cell proliferation and differentiation. Contrary to regeneration, prolonged starvation suppressed ALP activity. The above findings provide valuable information about the role of ALP in planarian regeneration and for its use as an indicator in ecotoxicology.     

Investigation of alkaline phosphatase activity in the serum of pregnant rats

An investigation was undertaken to determine if the placental alkaline phosphatase of the rat enters the maternal circulation and to study some of its characteristics. Unlike human, rat placental alkaline phosphatase was found to be heat labile and the alkaline phosphatase activity in the serum of both pregnant and non-pregnant rats was also found to be heat labile. Also unlike the human, the alkaline phosphatase activity in rat serum does not increase as pregnancy progresses to term. In an endeavour to establish if the rat placental enzyme is present in the serum of the pregnant rat, the characteristics of the enzyme in both placental extracts and serum of non-pregnant and 1-, 2- and 3-week pregnant rats were studied using the techniques of heat stability at 56°, gel filtration through Sephadex columns, disc gel electrophoresis, and L-phenylalanine inhibition. The presence of rat placental alkaline phosphatase in maternal serum could not be positively demonstrated by any of these procedures, suggesting that rat placental alkaline phosphatase does not enter the maternal serum.     

Variability of alkaline phosphatase activity in diploid human cells in vitro

Experiments were made with 19 strains obtained from different tissues (skin, lungs, muscles) of 8-10-week-old medical abortions and skin biopsies of healthy donors to study the manifestations of alkaline phosphatase (AP) activity in human diploid cells in vitro. Based on the data obtained it is concluded that AP activity is marked by demonstrable intra- and interstrain variability. The spectrum of "AP activity" trait variability is broader for transformed cells than for human diploid cells.     

A new in vitro exposure device for the mobile frequency of 900 MHz

A wire patch cell has been designed for exposing cell cultures during in vitro experiments studying possible effects of mobile radio telephone. It is based on the wire patch antenna which works at 900 MHz with a highly homogeneous field inside the antenna cavity. The designed cell structure is symmetric and provides a rather homogeneous field distribution in a large area around its centre. Moreover, the exposure cell can irradiate equally up to eight 35 mm Petri dishes at the same time, which enhances the statistical biological studies. To improve the specific absorption rate (SAR) homogeneity inside each sample, each dish is placed into another 50 mm dish. This way, SAR inhomogeneity is always proper for biological studies (below 30%). The main advantage of this new device is that it can provide SAR levels 20 times higher than those induced by classical Crawford transverse electromagnetic (TEM) cell. Moreover, this small open device is easy to construct and fits into an incubator. However, to be used for in vitro, the wire patch cell is a radiating element with the same radiating pattern as a dipole, and thus some absorbing materials are necessary around the system when used for in vitro experiments. Secondly, because of its narrow bandwidth, it is difficult to maintain its working frequency. To overcome this problem, a matching device is integrated into the test cell. In this paper, we present a detailed explanation of the cell behavior and dosimetric assessments for eight 35 mm Petri dishes exposed. Simulations using the Finite Difference Time Domain technique and experimental investigations have been carried out to design the cell at 900 MHz. The numerical dosimetry was validated by dosimetric measurements. These investigations estimated the dosimetric precision at 11%.     

Long-term exposure to a continuous 900 MHz electromagnetic field disrupts cerebellar morphology in young adult male rats

The pathological effects of exposure to an electromagnetic field (EMF) during childhood and adolescence may be greater than those from exposure during adulthood. We investigated possible pathological changes in the cerebellum of adolescent rats exposed to 900 MHz EMF daily for 25 days. We used three groups of six 21-day-old male rats as follows: unexposed control group (Non-EG), sham-exposed group (Sham-EG) and an EMF-exposed group (EMF-EG). EMF-EG rats were exposed to EMF in an EMF cage for 1 h daily from postnatal days 21 through 46. Sham-EG rats were placed in the EMF cage for 1 h daily, but were not subjected to EMF. No procedures were performed on the Non-EG rats. The cerebellums of all animals were removed on postnatal day 47, sectioned and stained with cresyl violet for histopathological and stereological analyses. We found significantly fewer Purkinje cells in the EMF-EG group than in the Non-EG and Sham-EG groups. Histopathological evaluation revealed alteration of normal Purkinje cell arrangement and pathological changes including intense staining of neuron cytoplasm in the EMF-EG group. We found that exposure to continuous 900 MHz EMF for 1 h/day during adolescence can disrupt cerebellar morphology and reduce the number of Purkinje cells in adolescent rats.     

Liver and spleen morphology, ceruloplasmin activity and iron content in serum of guinea pigs exposed to the magnetic field

The chronic exposure of guinea pigs to the magnetic field of induction 0.005 T and 0.3 T cause the morphological changes of spleen and functional disturbances of liver (the histochemical analysis indicate on greater amount of glycogen in hepatocytes). Everyday 1-hour exposure determined the drop in ceruloplasmin activity and an unchanged iron content in the serum of tested animals.