Reaction of melanocytes in vertebrate retina to the exposure to constant magnetic field

The influence of a constant magnetic field (strain 40 kA/m) on retina pigmentary cells of grass frog (Rana temporaria) and grey pigeon (Columba livia) eyes was investigated. Changes in the number and length of melanocytes appendixes were noticed accompanied by formation of thickenings in which melanosomes sized from 0.1 to 0.5 micron are moving. It is established that magnetic properties of eye retina pigmentary cells depend on the presence of Fe3+ in melanin. A theoretical model of paramagnetic receptor has been elaborated, according to which the induction of a magnetic field, formed by melanocyte, makes of the order 100 pT1. This value well compares with the size of magnetic field of a nervous impulse (120 pT1), extending throughout a nervous fibre of the frog sciatic nerve (Wikswo et al., 1980). This allows to suggest a possible unsynaptic way of transferring the information about the perceived magnetic field.     

DNA synthesis in cells of mouse corneal epithelium]

Method of autoradiography was used in order to study the kinetics of population of the cornea epithelium cells of mice. Intervals of different duration were found to exist in the DNA synthesis within the limits of S-period of one mitotic cycle. On the basis of personal and literature data a hypothesis has been put forward of a successive pattern of replication in the cells of eukaryots according to which synthesis of a fragment of the DNA daughter thread (or a chromosome subunit) occurs at each moment in a restricted site of a single matrix thread of DNA (matrix chromosome subunit). No DNA synthesis takes place at this moment in the complementary site of the second matrix thread (matrix chromosome subunit), the fragment (chromosome subunit) of one matrix thread being somewhat larger than the complementary fragment (chromosome subunit of the other matrix thread.     

Evaluation of preclinical signs due to exposure of workers to static magnetic fields

We report the use of granulocyte colony-stimulating factor (G-CSF) in a renal transplant recipient in whom neutropenia developed following a presumed viral infection. G-CSF was successful in producing a rise in neutrophil count which coincided with a resolution of fever; there was no adverse effect on renal function. This is the first use of G-CSF in a paediatric renal transplant recipient, and its use should be considered for the immunosuppressed child with persistent neutropenia.     

Observation of ultrastructural changes in cultured retinal pigment epithelium following exposure to blue light

BACKGROUND: The retina can be damaged by light even when levels of energy are well below the threshold for thermal damage, and the experimental damage of the retinal pigment epithelium (RPE) may be induced more easily by blue light than by longer wavelengths of visible light. The present study demonstrates the ultrastructural damage produced by exposure to blue light in cultured RPE. METHODS: Long-Evans rats were enucleated 8-10 days after birth for primary culture. One week after seeding, the monolayer culture of RPE cells was exposed to a cool blue light (wavelength = 440 +/- 10 nm) for 36 h (12 h/day, 3 days) at 2.0 mW/cm2. Transmission electron microscopy was used to compare the exposed RPE with the control. The entire experiment was repeated 3 times independently. RESULTS: The cytoplasm of the exposed RPE exhibited degenerative changes, such as large whorls of membrane, lamellar whorls and whorled inclusions. CONCLUSION: The RPE cells can be damaged directly by blue light after excluding the possible influence of phagosomes. This primary culture of RPE can also serve as an in vitro model for the study of light damage to the RPE.     

Dynamics of cardiac and skeletal muscle lactate dehydrogenase activity following a single exposure to an alternating magnetic field]

Analysis of records of microscopic slides from 33 patients with pure squamous carcinoma of the bladder who underwent radical cystectomy and lymphadenectomy disclosed a 5-year survival rate of 48 per cent. This survival rate correlated closely with pathologic stage and histologic grade of tumor and was significantly better than for each corresponding stage of transitional cell carcinoma of the bladder. The favorable survival rate and reasonably low operative mortality rate support aggressive therapy of this uncommon lesion.     

Damage to and regeneration of the kidney epithelium following crushing of the soft tissues of the extremities

Dynamics of the cellular composition in the proximal thin, thick areas of the loop, distal portions and collective tubules of the kidney was studied in rabbits after crush of the soft tissues of the limb. Planimetric method was applied to determination of the area of the nuclear epithelium of the proximal, distal portions and the collective tubules. A relationship was revealed between the injury of the epithelium of the nephrons and the collective tubules and its restoration, and also an intensification of mitotic activity, elevation of the relative number of pathological mitoses, and increase of the mean size of the cell nuclei.     

Chick embryo development can be irreversibly altered by early exposure to weak extremely-low-frequency magnetic fields

Several reports have shown that weak, extremely-low-frequency (ELF), pulsed magnetic fields (PMFs) can adversely affect the early embryonic development of the chick. In this study, freshly fertilized chicken eggs were exposed during the first 48 h of postlaying incubation to PMFs with 100 Hz repetition rate, 1.0 microT peak-to-peak amplitude, and 500 microseconds pulse duration. Two different pulse waveforms were used, having rise and fall times of 85 microseconds (PMF-A) or 2.1 microseconds (PMF-B). It has been reported that, with 2 day exposure, these fields significantly increase the proportion of developmental abnormalities. In the present study, following exposure, the eggs were allowed to incubate for an additional 9 days in the absence of the PMFs. The embryos were taken out of the eggs and studied blind. Each of the two PMF-exposed groups showed an excess in the percentage of developmental anomalies compared with the respective sham-exposed samples. This excess of anomalies was not significant for the PMF-A-treated embryos (P = 0.173), whereas it was significant for the PMF-B-exposed group (P = 0.007), which showed a particularly high rate of early embryonic death. These results reveal that PMFs can induce irreversible developmental alterations and confirm that the pulse waveform can be a determinant factor in the embryonic response to ELF magnetic fields. The data also validate previous work based on the study of PMFs' effects at day 2 of embryonic development under field exposure.     

Putative perception of rotating permanent magnetic fields following ingestion of LSD

We applied the Verbal Response Mode coding system to 80 medical interviews to characterize role dimensions of patient and physician and to assess the relation between physicians' role dimensions and patients' satisfaction. Role dimensions conformed closely to prior work. Physicians' acquiescence was positively correlated with satisfaction. This study suggests that the role dimensions generated by the Verbal Response Mode taxonomy are a useful measure of patients' and physicians' relationships.     

An autoradiographic study of the renewal of mouse bronchiolar epithelium following bromobenzene exposure

We report an experimental model of germanium dioxide (GeO2)-induced neuropathy in rats. More than 6 months administration of GeO2 to young rats produced neuropathy characterized by segmental demyelination/remyelination and nerve edema. Electron microscopic studies demonstrated that changes in Schwann cells, such as an increased cytoplasmic volume or disintegration of the cytoplasm, were the earliest pathological findings. Schwann cell mitochondria contained high electron-dense materials. Subsequent removal of necrotic Schwann cell debris and myelin by invading macrophages was evident. These findings suggested that the Schwann cells themselves are the primary target of the toxin. The deposition of electron-dense granules in the intra-axonal vesicles, which was suggestive of glycogen granules in mitochondria, was observed in the advanced stage of the neuropathy. The findings of endoneurial edema with splitting of myelin lamellae were noted at the early stage of demyelination. Nerve edema may be the result of GeO2-induced endothelial cell injury.     

Renewal of the terminal bronchiolar epithelium in the rat following exposure to NO2 or O3

Rats were exposed to either NO2 or O3 to determine whether nonciliated cells (Clara cells) could divide and differentiate into ciliated cells in the terminal bronchioles. Dividing cells were labeled with tritiated thymidine, visualized in the light and electron microscopes using autoradiographic techniques, and studied for up to 15 days after labeling. Electron microscopic autoradiography 1 hour after injection of tritiated thymidine showed that all labeled cells in the terminal bronchioles were nonciliated. However, 4 days after injection of tritiated thymidine, 67.8 per cent of the labeled cells were nonciliated and 32.2 per cent were ciliated. Light microscopic autoradiography showed that the new labeled ciliated cell population was stable for up to 15 days. These results indicate that nonciliated cells divide and the sister cells may form new ciliated and nonciliated cells. Thus, nonciliated cells can act as progenitor cells for the terminal bronchiolar epithelium.     

Effect of a constant magnetic field of ultra-high intensity on the morphologic composition of peripheral blood

An exposure of mice to a constant magnetic field (CMF) of 9.9, 25.4 and 39.4 kersted produced changes in the leucocyte and reticulocyte counts and caused no changes in the red blood cell count and hemoglobin. The changes noted during and after the exposure were of a cyclic pattern. During a 24-hour exposure of animals to a CMF of 39.4 kersted a short-term increase in the reticulocyte and leucocyte counts and a concomitant decrease of the neutrophil and lymphocyte counts were noted. Afterwards the reticulocyte count decreased and increased again by the end of the exposure. Following a 3-hour exposure to CMFs of the above intensities the changes persisted for 20-35 days. Normally the parameters increased during the 1-2 days of the exposure and decreased thereafter. The level of changes was not correlated with the CMF intensity. The increase in the reticulocyte count during and exposure to a CMF of 39.4 kersted was identical to that during an exposure to a CMF of I kersted.     

A case cohort study of suicide in relation to exposure to electric and magnetic fields among electrical utility workers

BACKGROUND: All-trans retinoic acid is currently used in clinical trials in combination with tamoxifen to treat breast cancer, and 13-cis retinoic acid is used with a-interferon to treat metastatic endometrial cancer. We examined the effects of all-trans retinoic acid and 13-cis RA alone on endometrial adenocarcinoma (RL95-2) cells to investigate the cell biological mechanisms by which retinoic acid may reduce the metastatic phenotype and induce differentiation. METHODS: RL95-2 cells were seeded onto 4-chamber plastic slides and treated with 13-cis retinoic acid or all-trans retinoic at 0.5 microM, 1 microM and 5 microM doses for 90 minutes at 37 degrees C and stained for F-actin. RESULTS: Untreated RL95-2 cells exhibited staining of disrupted aggregates of F-actin only near the cell periphery. Cells treated with the three doses of 13-cis retinoic acid exhibited a dramatic reorganization of F-actin throughout the cells. When cells were treated with 0.5 microM all-trans retinoic acid, actin filaments reorganized. Cells treated with 1 microM all-trans retinoic acid and 5 microM all-trans retinoic acid displayed increased organization of F-actin and cell size increased. The percentage of S-phase cells increased at the high doses of retinoic acid treatment. This effect was apparently transient, since retinoic acid did not significantly affect cell growth. CONCLUSION: An organized cytoskeleton and an increase in cell size are associated with differentiation. We suggest that retinoic acid exerts its effects on these transformed cells by reorganizing actin filaments, and inducing differentiation, thus inducing a more stationary phenotype.     

Demographic evaluation of the fertility of aluminium industry workers: influence of exposure to heat and static magnetic fields

A demographic analysis of the fertility of French aluminium industry workers was performed in order to evaluate the potential effects on male fertility of occupational exposure to heat and static magnetic fields occurring in certain workshops. Two groups of aluminium workers were studied: one group of 692 potroom workers exposed to heat and to static magnetic fields, and a control group of 588 workers from the same plants, who had not been exposed to these factors. The birthrate was significantly higher in the 'exposed' group than in the 'control' group. The relative birthrate ratio ('exposed' versus 'control') was 1.1 (P < 0.001). These results do not show any decrease in the fertility of potroom workers exposed to heat and static magnetic fields, when compared to other workers in the aluminium producing industry.     

Condition of the microcirculatory bed of cat ventricular myocardium following exposure to gravitational stress]

The status of microcirculatory bed in the cat ventricular myocardium was studied after a single (10 units for 3 min) and repeated effect (6 units for 3 min every other day for a month) of overloading in the cranio-caudal direction (+Qz). The material to examine was taken in 20 min, 1, 3, 7 and 30 days after the completion of the experiment. The myocardial vessels were injected with water emulsion of Indian ink and studied by routine histological methods, amino nitrogen silver impregnation and electron microscopy. A single overloading was stated to result in changes of capillary permiability which was evident in the increasing amount of pinocyte vesicles, polysoma and endothelial plasmic processes. The effect of repeated overloadings produces more severe disorders in the walls of different components of the myocardial microcirculatory bed.     

Changes in pain perception and pain-related somatosensory evoked potentials in humans produced by exposure to oscillating magnetic fields

cDNA selection was used to isolate coding sequences from cosmids mapping to the gene-rich telomeric region of human chromosome 21q. A novel cDNA, termed SMT3A, was isolated and mapped between the loci PFKL and D21S171, about 2.2 Mb proximal to the telomere. The predicted protein of 103 amino acids appears to be a homologue of the Saccharomyces cerevisiae SMT3 protein, whose gene was previously isolated as a suppressor of mutations in the MIF2 gene. The yeast MIF2 gene encodes an essential centromeric protein and shows homology to mammalian CENP-C, an integral component of active kinetochores. SMT3A was found to be highly homologous to two other recently isolated human genes, suggesting the presence of a new gene family. Homologous sequences were also found in protozoa, metazoa, and plants. Moreover, all predicted proteins show significant homology to ubiquitin. The proposed role of yeast SMT3 as centromeric protein and the strong evolutionary conservation of the SMT3A gene suggest an involvement of the encoded protein in the function and/or structure of the eukaryotic kinetochore.