M. P. De Miguel

Long-Term Effects of ELF Magnetic Fields on the Mouse Testis and Serum Testosterone Levels

Male OF1 mice were exposed continuously to a magnetic field of 50 Hz and 15 μT (rms) in order to elucidate the possible alterations in testis histology and its endocrine function caused by this exposure. Mothers were chronically exposed from the age of 6 weeks and had their offspring under the same experimental conditions. Offspring were sacrificed at the age of 10 weeks and the testes were removed and studied histologically. Serum testosterone levels were measured by enzymatic immunoassay. A significant increase in the size and weight of the testes, not related to the increment of the body weight (gonadosomatic index increased), was found in the experimental group compared to the control group. Histologically, this finding is due to an increase in the interstitial tissue, associated with increased levels of testosterone in the blood. Complete spermatogenesis was found in all the animals, in both the control and experimental groups. No differences were found in the morphology of the seminiferous epithelium.

Long-term behavior of an arterial autograft: a new role for intimal hyperplasia?

The long-term behavior of an arterial autograft was studied with special attention to the evolution of intimal hyperplasia. An arterial autograft measuring approximately 5 mm in length was implanted in the right common iliac artery of female Sprague-Dawley rats. Animals were sacrificed at 90, 120, 150, 180, 240, 360, 400, 540 and 730 days after implantation. Grafts were evaluated by optical microscopy, electron microscopy, and morphometry. Myointimal cells were marked using an antiactin monoclonal antibody and studied by transmission electron microscopy. In the long term, the myointima of the arterial wall appeared as a consolidated layer formed by smooth muscle cells of contractile phenotype, abundant extracellular material consisting of clumps of elastin and collagen fibers. Cell maturity and degree of differentiation were demonstrated by the incorporation of antiactin antibody. The medial layer of the grafted segment suffered a marked long-term loss of cells and became an acellular layer sustained by the elastic layers. The adventitial layer was markedly cellular and had abundant vasa vasorum. Morphometry showed that the myointimal layer in the operated territory was not uniform and consisted of tongues of varying thickness. The total thickness of the arterial wall did not differ significantly (p > 0.05) between the graft and the proximal and distal areas. The results suggest that the intimal hyperplasia originating during the repair process could assume some functions of the degenerated medial layer, maintaining long-term vascular homeostasis.

Intermediate filaments in the testis of the teleost mosquito fish Gambusia affinis holbrooki: a light and electron microscope immunocytochemical study and Western blotting analysis

SummaryA light and electron microscope immunocytochemical study and Western blotting analysis has been performed on intermediate filaments (vimentin, desmin and cytokeratins) in the testis of the teleost fish Gambusia affinis holbrooki. An immunoreaction to vimentin was observed in the epithelium of the efferent ducts, testicular canal and their surrounding peritubular cells. Positive vimentin immunostaining was also observed in the cells located around seminiferous tubules (boundary cells), Leydig cells, interstitial fibroblasts, chromatophores, and blood vessel endothelial cells. In contrast to mammals, no vimentin immunoreactivity was found in the Sertoli cells. Immunoreactivity to desmin was weak in the epithelial cells of the efferent ducts and testicular canal and intense in the peritubular cells that surrounded these ducts. Desmin immunoreactivity was also observed in the seminiferous tubule boundary cells. The immunoreactivity was weak in the boundary cells that surrounded germ cell cysts containing spermatogonia or spermatocytes and intense in the boundary cells around cysts with elongated or mature spermatids. Immunoreactivity towards cytokeratins was observed only in testicular blood vessels. Cytokeratin immunolabelling was intense in the endothelium and weak in the vascular smooth muscle cells. No cytokeratin immunoreactivity was found in the Sertoli cells, germ cells, interstitial cells or in the efferent duct epithelium. The absence of intermediate filaments in the Sertoli cells, the absence of cytokeratins in the epithelium of the sperm excretory ducts, and the presence of desmin filaments in these epithelial cells are the most important differences with regards to the intermediate filament phenotype in mammalian testes.

Changes in Mouse Adrenal Gland Functionality Under Second-Generation Chronic Exposure to Elf Magnetic Fields. I. Males

The second generation of male OF1 mice chronically exposed to a magnetic field of 50 Hz and 15 µT were studied to elucidate the possible histological and endocrinological alterations in adrenal gland caused by this exposure. Animals were sacrificed at the age of 10 weeks. Cortisol plasma concentrations were determined by fluorescence polarization immunoassay, and adrenal glands were studied by histopathological methods. The body weight of the exposed animals was found to be significantly increased. Cortisol plasma concentration and adrenal cortex thickness lost the daily rhythmicity. The statistical histopathological study showed no differences in exposed versus control animals. However, 15–20% of the experimental mice present nodular cortical hyperplasia with hypertrophy, increase in dark cells, and islets of cells with large lipid vacuoles. At the ultrastructural level, a dramatic decrease in lipid content and increase in mitochondria and SER compartment and in the nuclear and nucleolar volumes were fou...

Interactions of ELF Magnetic Fields with Mouse Skeletal Muscle

The second generation of female OF1 mice exposed chronically to a magnetic field of 50 Hz and 15 μT (rms) was studied to find out the possible alterations in the skeletal muscle caused by this exposure. Animals were sacrificed at the age of 14 weeks, and their skeletal muscle studied by spectrophotometric and histopathological techniques. Calcium concentration was found to be significantly decreased in the experimental animals, while H2O content, Na, K, Fe, Ni, Mg, and Zn concentrations were not significantly different from those of control animals. Histologically, we found variation in fiber size, rounded and widely separated fibers, centrally located nuclei, and intermyofibrillar lipids. We could not find necrosis, inflammatory infiltrate, or loss of either the filaments or the cross-striation.

ELF Magnetic Fields and Protein Changes in Mouse Skeletal Muscle

The second generation of female OF1 mice exposed chronically to an ELF field of 50 Hz and 15 μT (rms), generated in a Helmholtz coil system, was studied to determine the possible protein changes in the skeletal muscle associated with this exposure. Animals were sacrificed at the age of 14 weeks, and their quadriceps skeletal muscles were studied by electron microscope immunocytochemistry to detect the possible changes in different proteins. Actin, myosin, desmin, and vimentin immunolabeling was found to be similar in both control (unexposed) and experimental (exposed) animals. Dystrophin was found to increase in the sarcoplasmic reticulum in the exposed animals with respect to the control ones. α-Actinin was found to increase in some damaged Z-bands of the experimental animals; troponin and calmodulin increased all along the sarcomere of the muscles of the exposed mice, whereas titin and nebulin immunoreactions decreased in the sarcomeres of the experimental group. The observed changes in these proteins s...

Ultrastructure and lectin cytochemistry of the cloacal kingsbury's glands in the male newt Triturus marmoratus marmoratus

The aim of this study was the morphological and histochemical characterization of Kingsburys glands in the male newt Triturus marmoratus marmoratus in the pre-reproductive and post-reproductive period of the testicular cycle, using light and electron microscopy and lectin histochemistry. The Kingsburys glands are a small group of tubular glands that surrounds the cloacal tube. In the pre-reproductive period, Kingsburys glands showed a cuboidal epithelium that was partially surrounded by myoepithelial cells. Most of the cuboidal cells showed numerous secretion granules in their cytoplasm. About 1 of 23 epithelial cells were mitochondria-rich cells that contained abundant mitochondria instead of secretion granules. In the post-reproductive period, the glandular epithelium decreased in size and did not show the characteristic secretion granules, and the glandular lumen was very reduced. The mitochondria-rich cells underwent no changes in this period, whereas the myoepithelial cells became larger. The lectin pattern of secretory cells in the pre-reproductive period was the following: the nuclei appeared strongly labeled with WGA, ConA, and SBA lectins, and scarcely with UEA-I; the cytosol was exclusively labeled with LcA; the rough endoplasmic reticulum was labeled with ConA and LcA; the Golgi complex appeared labeled to PNA, HPA, and UEA-I; and the secretion granules labeled with all the lectins tested. Mitochondria-rich cells and myoepithelial cells showed labeling to SBA, WGA, and ConA lectins but only in their nuclei. In the post-reproductive period, the nuclei of the three cell types were labeled with WGA, ConA, and SBA. In addition, the cytosol of the secretory cells was labeled with LcA, and that of myoepithelial cells with ConA. J. Exp. Zool. 281:228–237, 1998.

Histopathological Changes in Mouse Adrenal Gland Under Second-Generation Chronic Exposure to so-Hz Magnetic Fields. II. Females

Female OF1 mice were chronically exposed to a sinusoidal magnetic field of 50 Hz and 15 µT to determine the possible histological alterations in their adrenal glands caused by this exposure. Mice were sacrificed at 14 weeks of age, and adrenal glands were studied by light and electron microscopy. Both glands of a total of 30 female control mice and 30 experimental ones were used for this study. The morphological parameters measured did not show significant differences between the compared groups. In 30% of the exposed mice one or several of the following morphological variations were found: enlarged capsule, with infiltration of both the zonae glomerulosa and fasciculata; wider zona glomerulosa with hyperplasic micronodules, with the cells showing swollen mitochondria with dilated cristae; in the zona fasciculata, several groups of fuscinophilic cells, dysplasia, hyperplasia with hypertrophy, and even adenoma in a small percentage; in the zona reticularis, the cells had increased lipid content and mitocho...

Ultrastructure and lectin cytochemistry of the cloacal ventral glands in the male newt Triturus marmoratus marmoratus.

Ventral glands are found in the cloacal walls of male urodele amphibians except for sirenids. These glands are mucous, and secrete substances that will form part of the spermatophore used in transfer of sperm during fertilization. Ventral glands are formed by secretory and ductal portions; both possess epithelial and myoepithelial cells with different characteristics. Urodeles have cyclic reproduction, and cloacal ventral glands show seasonal differences with electron microscopy. The glycoproteins secreted by these glands have been studied by means of lectin histochemistry. The labeling was detected mainly in the nuclei, rough endoplasmic reticulum, Golgi complex, and cytosol. Secretory granules in these glands are composed by mucous glycoproteins that bind PNA lectin (which binds galactose) and SBA and HPA lectins (N‐acetylgalactosamine), UEA‐I (fucose), and LcA (glucose and/or mannose). These findings suggest that the mucins secreted by ventral glands contain both N‐ and O‐linked oligosaccharides. Ventral glands secrete higher quantity and more diverse mucous substances in the reproductive period, as confirmed by lectin‐histochemical reactions. Based on these results, the major similarity between ventral cloacal glands and accessory mammalian glands, can be established with bulbourethral glands. Microsc. Res. Tech. 45:122–129, 1999.