Electron microscopic examination of the effects of methyl parathion exposure on the ovaries.

OBJECTIVE: In our study, we aimed to investigate histopathological effects of chronic methyl parathion exposure on ovaries at electron microscopic level. MATERIALS AND METHODS: In this study, Wistar albino type, adult, female rats with an average weight of 190-250 g were used. 30 female rats, included in this study, were divided into 3 groups. Group I received only saline and was evaluated as the control group, whereas Group II received 1/50 percent of LD50 dose of methyl parathion and Group III received 1/20 percent of LD50 dose of methyl parathion every day at 130 pm orally by gavages during two estrus cycles (8 days). The rats at proestrus stage on the morning of 9th day of the study underwent bilateral ovariectomy. Ovarian tissues of the control and drug groups were examined under the electron microscope; primordial and growing follicles were included in the evaluation, however, corpora lutea were excluded taking into account the presence of remaining regressive corpora lutea from the previous cycles. RESULTS: Following examination of ovarian tissues of rats exposed to 1/50 and 1/20 percent of LD50 dose of Methyl parathion at electron microscopic level, it was detected that significant structural changes had occurred in developing follicles and ovarian stroma in both drug groups, and that primordial follicles had not been affected significantly from methyl parathion but necrosis had been developed in oocyte and granulosa cells of developing follicles, and that in 1/20 group in addition to these changes, apoptotic changes had been found in granulosa cells of developing follicles. CONCLUSIONS: As a result of chronic exposure to methyl parathion, rat ovaries are significantly affected and follicular development is impaired. This state may explain the cause of infertility due to chronic pesticide exposure.

Effect of melatonin on the cardiotoxicity of doxorubicin.

This study was designed to investigate the preventive effect of melatonin on doxorubicin's most important side effect, cardiotoxicity. Forty male albino Wistar rats were utilized and the rats were divided into five groups: group I, 0.9% NaCl for 4 days; group II, doxorubicin 3 mg/kg/day for 4 days; group III, 2.5 % ethanol for 15 days; group IV, melatonin 6 mg/kg/day for 15 days; and group V, a doxorubicin and melatonin combination were administered intraperitoneally. At the end of the experiment, tissue samples obtained from the cardiac muscle of the left ventricle of the rats were processed for measurement of malondialdehyde and for electron microscopic examination. Malondialdehyde, a product of lipid peroxidation, was found to be significantly higher in the doxorubicin group. However, in the doxorubicin and melatonin combination group the level of malondialdehyde was decreased statistical significant. The histological examination revealed destruction of myofibrils, disorganization of sarcomeres, mitochondrial degeneration and formation of giant mitochondria and lipid accumulation in the doxorubicin group. Also, accumulation of filamentous structures in the sarcoplasma in some of the cells, structural changes in capillaries and an increase in collagen fibers forming bundles were observed. When melatonin was added to the doxorubicin treatment all structural changes were reduced. The cardiotoxic side effect of doxorubicin used as a chemotherapeutic agent and was probably developed as a result of suppression of the antioxidant system and lipid peroxidation. Therefore, it could be assumed that the addition of melatonin in the treatment of doxorubicin could prevent the cardiotoxicity of doxorubicin.

Antigen-presenting cells in the hypertrophic pharyngeal tonsils: a histochemical, immunuhistochemical and ultrastructural study.

The antigen presenting cells (APCs) with special interest to dendritic cells (DC), were investigated in 28 hypertrophic and 10 control pharyngeal tonsils of children by histochemistry, immunohistochemistry and electron microscopy. In this study, we are trying to clarify the function and classification of APC in pharyngeal tonsils using morphologic criteria, Human Leukocyte Antigen Monoclonal Antibody (HLA-DR MoAb), which is specific for APCs, and acid phosphatase (APh) reacting with both phagosomes and lysosomes. The surface epithelium of the patient group examined by light microscopy, heavy infiltration of lymphocytes, degenerated columnar cells and a few HLA-DR MoAb (+) columnar cells was observed. Additionally, a significant number of APCs which were Langerhans cells (LCs), interdigitating dendritic cell (IDC), follicular dendritic cell (FDC) and macrophages were stained with both HLA-DR MoAb and APh in the epithelial, interfollicular-subepithelial and follicular areas. Ultrastructural examinations revealed that lymphocytes, macrophages, LC and M cells were found among the surface columnar epithelial cells of the patient group. The interactions between M cells and LC suggested that M cells probably passed antigens from surface to LC. In the interfollicular-subepithelial areas of the hypertrophic pharyngeal tonsil, IDCs were in close contact with lymphocytes, macrophages and plasma cells. Seven types of FDCs (FDC-1 - FDC-7) were recognised according to their ultrastructural appearances. Differentiated FDCs (FDC-4) were also in close contact with each active subtype of FDCs in follicular areas besides lymphocytes. These findings supported the idea that although the pharyngeal tonsils contained several types of active APCs, only DC were in close contact with immunocompetent cells and the other APC's. Therefore, these morphologic appearances of DC could be a sign of function to initiate the immune response of the pharyngeal tonsil.

Analysis of chromosome aberrations in a mammary carcinoma cell line from a dog by using canine painting probes.

A cell line derived from a spleen metastasis of a mammary carcinoma in a female dog was analyzed by fluorescence in situ hybridization with canine chromosome-specific paints. The cell line showed a modal chromosome number of 77, with three (90% of the cells) or four (10% of the cells) biarmed chromosomes. Aberrations observed relate to chromosomes 8 or 11, 13 or 15, 37, 38, and X and include chromosome loss (X), formation of isochromosomes (8 or 11, 13 or 15), and centric fusion (37 and 38). In all aberrations, whole chromosomes are involved. None of the genes known to be related to breast cancer development in humans and that has mapped in the dog is located on one of the aberrant chromosomes. The results of this study show that chromosome painting is a most useful tool for the analysis of canine tumor cells.

Ultrastructural and hormonal changes in the contralateral adrenal gland in unilateral adrenal gland ischemia: an experimental study in rats.

While it is well known that unilateral tissue ischemia may result in contralateral damage in some paired organs, there is no universally accepted mechanism to explain why these contralateral changes occur. The aim of the present study was to investigate the ultrastructural and hormonal changes that occur in the contralateral nonischemic adrenal gland after unilateral ischemia of an adrenal gland in a rat model. The animals were divided into four groups of four rats each; namely, a control group which received a sham operation without any ischemic insult, a 2-h ischemic group, a 4-h ischemic group, and an 8-h ischemic group. The left adrenal blood vessels were ligated in all ischemia groups and blood samples were taken for hormonal study 2, 4, and 8 h later, after which bilateral adrenalectomy was performed to determine the ultrastructural changes. The plasma concentrations of aldosterone and cortisol were determined by radioimmunoassays. There was an increase in both aldosterone and cortisol levels related to the duration of the ischemia, but the differences among the groups were not statistically significant. Contralateral ultrastructural damage such as heterochromatin in nuclei, mitochondrial degeneration, endoplasmic reticulum cisternal widening, increased lipid droplets, and lysosomes, were demonstrated electron-microscopically after unilateral adrenal ischemia.

Adenoids and otitis media with effusion: a morphological study.

PURPOSE: Adenoidectomy, especially for the treatment of suppurative otitis media, has been used for a very long time. In this study, the role of adenoids in the origin of otitis media with effusion was investigated by using light microscopy, immunocytochemistry, enzyme chemistry, and electron microscopy. MATERIALS AND METHODS: A group of 28 children with otitis media with effusion (OME) was identified. Ages ranged from 3 to 12 years. A control group of 10 age-matched children without any middle ear and upper respiratory tract infection served as the basis for comparison. Specimens obtained at surgeries from both groups were divided into groups for light microscopy, immunocytochemistry, enzyme cytochemistry, and electron microscopy and then all were examined blindly. Also, quantitative analysis of antigen-presenting cells was performed blindly on 10 patients and 10 controls. RESULTS: There was an increase in the number of lymphocytes, mast cells, plasma cells, macrophages, dendritic cells, and M cells in the adenoids of patients with OME when compared with the normal cases. Stratified squamous epithelial areas, collagenous fibers, and fibrocytes were also increased in the patient group. Antigen-presenting functions of epithelial cells are shown by major histocompatibility complex (MHC) class II positivity of some ciliated-columnar epithelial cells in the patient group. CONCLUSION: Adenoid tissues of patients with OME in this study seem to be infectious foci, aggravating immune reactions, which might attack the middle ear through an ascending route.

Ultrastructure of the nasopharyngeal orifice epithelium of the eustachian tube in otitis media with effusion.

Epithelial changes in nasopharyngeal orifice of eustachian tube in 15 patients with otitis media with effusion (OME) were studied. Ultrastructural examination of the epithelium revealed distinct alterations in the ciliated cells, intermediate cells and in the columnar cells with microvilli. The ciliated cells were the predominant cell type in the epithelium and were characterized by compound cilia and apical cytoplasmic bulgings with fine granular content. The intermediate cells showed more prominent lateral cytoplasmic bulgings. Cytoplasmic bulgings of both cell types eventually pinched off and set free as cytoplasmic bodies, similar to the cytoplasmic bodies derived from lymphocytes. As a result of epithelial destruction, the lumen of nasopharyngeal orifice was occupied by epithelial cellular debris among which leucocytic cells and cytoplasmic bodies with fine granular content. This accumulation in the lumen probably developed as a result of defective mucociliary activity which is due to compound cilia formation in the ciliated cells. Moreover, ultrastructural resemblance of cytoplasmic bodies derived from ciliated cells, intermediate cells and leucocytic cells indicates the possible role of these cells in common immune defence mechanisms in chronic otitis media with effusion.

The effect of toluene on the rat ovary: an ultrastructural study.

In this study, eighteen Wistar female albino rats were used to observe the ultrastructural effects of toluene on the rat ovaries. The animals were divided into experimental and control groups. The experimental group was exposed to 3,000 ppm toluene/m3 for 7 days and 8 h/day. At the end of the experiment the main ultrastructural findings related to the oocytes of the antral follicles of the experimental group were: abundant vacuoles, lytic areas, degenerative mitochondria in the ooplasm and blunt microvilli on the surface. Furthermore, the granulosa cells revealed prominent degenerative changes such as pyknotic nuclei, mitochondrial alterations and dilatation of the endoplasmic reticulum (ER) cisternae. It was interesting to note tht the ultrastructure of primordial follicles was almost similar in both experimental and control groups. All these findings suggested that, although toluene did not affect the primordial follicles, the growing follicles showed degenerative changes attributable to the inhalation of a toxic agent such as toluene.

Electron microscopy of psoriatic skin before and after psoralen/ultraviolet A treatment.

Skin biopsy specimens of patients with psoriasis receiving psoralen/ultraviolet A treatment were examined. A decrease in tonofilaments and keratohyaline granules and enlarged intercellular spaces were common findings in all cases. Hyperchromatic nuclei in the horny cells and hyperactive keratinocytes in the malpighian layer were also observed. Treatment resulted in normalization of keratinocytes and stimulation of melanocytes. Our study revealed that psoralen/ultraviolet A is effective and important in the treatment of psoriasis, but patients should be evaluated for atypical changes.

Alport's syndrome with bilateral macular hole.

In this study 8 patients with Alport's syndrome are presented. The ocular manifestations of these patients were retinal flecks, macular depigmentation, microspherophakia and anterior lenticonus. One patient revealed bilateral macular hole which was an unusual feature. Four patients had renal biopsies with the characteristic electron microscopic changes of the disease. According to these findings our conclusion is that Alport's syndrome is a disorder of selected basement membranes.

Effects of naloxone on sodium- and potassium-activated and magnesium-dependent adenosine-5'-triphosphatase activity and lipid peroxidation and early ultrastructural findings after experimental spinal cord injury.

Endorphins have been implicated in the pathophysiology of spinal cord injury. The effect of naloxone on the sodium- and potassium-activated and magnesium-dependent adenosine-5'-triphosphatase (Na(+)-K+/Mg+2 ATPase, EC.3.6.1.3.) activity, lipid peroxidation, and early ultrastructural findings were studied in rats at the early stage of spinal cord injury, produced with an aneurysm clip on the T2-T7 segments. The rats were divided into four groups. The 10 rats in Group I, which had no injury and received no medication, were used for determining Na(+)-K+/Mg+2 ATPase activity, the extent of lipid peroxidation (by measuring the level of thiobarbituric acid-reactive substances as malondialdehyde), and normal ultrastructural findings. On the 15 rats in Group II, without spinal cord injury, only laminectomy was performed to determine the effect of surgery on the biochemical indices and findings. In the 15 rats in Group III, physiological saline was administered intraperitoneally in an amount equivalent to that of the naloxone administered immediately after spinal cord injury. In the 15 rats in Group IV, 0.5 mg of naloxone was administered intraperitoneally as a single dose immediately after injury and again 60 minutes after injury. The Na(+)-K+/Mg+2 ATPase activity was promptly reduced after spinal cord injury and remained in a lower level than the levels of Groups I and II during 120 minutes after injury. Naloxone treatment, immediately after trauma, attenuated the inactivation of Na(+)-K+/Mg+2 ATPase. On the other hand, there was a significant difference in the malondialdehyde content between animals in Groups I and III. Naloxone treatment reduced the malondialdehyde content in Group IV.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental evaluation of peritoneum and pericardium as dural substitutes.

Although many substances have been tested in the search for an ideal dural substitute, an entirely satisfactory material has still not been found. The authors report an experimental study involving the closure of dural defects in rabbits with biomaterials developed from pig peritoneum and pericardium. Macroscopic and histologic examination, performed over a period between 15 and 45 days after implantation showed slight or no adhesion between the graft material and the cortex. No infection, CSF leakage, fistula or toxicity was noticed. The results demonstrated that these biomaterials could be used as satisfactory dural substitutes.