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PubMed2005

[Effects of prenatal methylmercury exposure on learning and memory ability of mice and ultrastructure of hippocampus neurons in mice].

OBJECTIVE: To study the effects of prenatal methylmercury exposure on learning and memory ability of mice and ultrastructure of hippocampus neurons in mice. METHODS: Methylmercury in doses of 0 and 4mg/(kg x d) were fed to pregnant mice at 7th-9th day after conception. Learning and memory ability of the mice offspring was detected. The ultrastructure of hippocampus neurons was observed by electron microscope after the completion of the experiment. RESULTS: The learning and memory ability of the mice offspring of 4 mg/(kg x d) dose group was lower than those of 0 mg/(kg x d) dose group (P < 0.05). Changes in the ultrastructure of hippocampus neurons were obvious in 4 mg/(kg x d) dose group as compared with the 0 mg/(kg x d) dose group. CONCLUSION: Methylmercury could affect the growth and development of central nerve system. The learning and memory ability of mice offspring was greatly damaged and the ultrastructure of hippocampus neurons was changed by methylmercury.

Animals↗
PubMed2004

Investigations of ultrastructure of damaged and regenerated skeletal muscle fibers.

Our investigations concerned the head of the parietal part of quadriceps femoris, and we based our investigation on observations of the ultrastructure of muscle fibers using an electron microscope. We observed tissue samples taken from patients (10 men) 25-35 years old, who had old damage of knee joint ligament (after about 6 week's immobilization). In the first group, segments of tissue of parietal head of quadriceps femoris were taken inter-operationally from patients in whom there was found old damage of knee joint ligament. The second group was of tissue segments of this muscle after surgical repair of knee and rehabilitation, which consisted in power training using resistance machines. The muscle fiber samples of quadriceps femoris which were taken from patients during the first operation, showed big changes in their ultrastructure. These changes included: myofibrils disintegration; disturbance of regularly arranged striation in sarcomers; dissappearance of Z line. In the sarcoplasm, we observed large vacuolisation, and in the interfibrillar spaces--an accumulation of exudate and morphotic elements of blood outside the capillary vessels. Observations of muscle tissue after regeneration, showed a big improvement in the muscle cell's ultrastructure--the myofibrils were regularly arranged, and the sarcomers striations showed no deviations from normal structure. We also observed a considerable increase in the number of properly formed ultrastructure mitochondria when compared with the first group.

Adult↗
PubMed2005

Clinicopathological, immunohistochemical, and ultrastructural study of 13 cases of melanotic schwannoma.

BACKGROUND: Melanotic schwannoma is a rare variant of schwannoma composed of melanin-producing cells with ultrastructural features of schwann cells. The description of the course of the tumors differs somewhat, but it is generally considered as a benign lesion. We investigated the clinicopathologic features, immunophenotypes, and ultrastructural features of 13 patients with nonpsammomatous melanotic schwannoma (NPMS). METHODS: Tumor specimens of each patient were sectioned and stained with hematoxylin-eosin, Fontana-Masson, Prussian blue, and periodic acid-Schiff (PAS). Immunohistochemical markers such as S-100, Leu-7, HMB-45, Melan-A, CK, EMA, vimentin, GFAP, laminin, collagen IV and MIB-1 were detected with the Envision immunohistochemical staining method. Four of the cases were observed by electron microscopy. RESULTS: Of the 13 patients, 8 were male and 5 female, aged from 11 to 92 years (mean, 38.6 years). The tumor sites included the spinal nerve root (5 patients), cranial nerve (1), greater omentum (1), subcutaneous tissue (3), mesentery (1), bone (1) and mediastinum (1). Eleven patients were followed up for over 2 years, with a mean of 5.9 years. One patient (9.1%) with a primary tumor in the greater omentum developed another primary tumor of the same type in the subcutaneous tissue of the abdominal wall after the first operation. Local recurrence of the tumor was seen in 2 patients (18.2%). One patient (9.1%) showed the local recurrence and metastasis. Seven patients (63.6%) showed no evidence of the recurrence or metastasis. Grossly, all tumors were well-circumscribed and the gross findings were suggestive of melanin-containing tumors. The tumor was composed of spindled and epithelioid cells with abundant intracytoplasmic melanin pigments. Nuclei were round and contained delicate, evenly distributed chromatins as well as small, distinct nucleoli. In some areas, the nucleoli were large and prominent. Rare mitoses were seen in most lesions except the larger omentum lesion. The pigment was shown to be positive for the Fontana-Masson and negative for Prussian blue and PAS. Immunohistochemical staining for S-100, Leu-7, HMB-45, Melan-A, and vimentin were strongly positive. Linear immunoreactions of both laminin and collagen IV was detected in all patients. Ultrastructurally, numerous elongated tumor-cell processes, duplicated basement membrane and melanosomes were observed in all developmental stages. CONCLUSIONS: Histologically, melanotic schwannoma is a rare variant of schwannoma composed of melanin-producing cells with ultrastructural features of schwann cells. Distinguishing between this tumor and malignant melanoma is of paramount importance in planning of management. Immunohistochemically, combined use of laminin and collagen IV is valuable in distinguishing melanotic schwannoma from malignant melanoma. Wide local resection and additional radiotherapy should be advocated. Further studies including cytogenetic or molecular biology are still required to better delineate melanotic schwannoma from malignant melanoma. Appropriate long-term follow-up is needed for all melanotic schwannomas.

Adult↗
PubMed2005

[Ultrastructural changes of rat ischemic myocardium after bone marrow mesenchymal stem cell transplantation].

OBJECTIVE: To observe the ultrastructural changes of ischemic myocardium of rats after bone marrow mesenchymal stem cells (MSCs) transplantation. METHODS: Rat models of myocardial ischemia were established by ligating the descending anterior branch of the left coronary artery. The isolated and in vitro cultured MSCs labeled with 4' 6-diamidine-2-phenylindole (DAPI) were injected into the rats via the tail vein and the hearts of the rats were taken 1 week and 8 weeks after transplantation, respectively, for observation under fluorescence microscopy. The ultrastructural changes of the ischemic myocardium of the recipient rats were observed by transmission electron microscope. RESULTS: The third passage of cultured MSCs growing in colonies possessed good homogeneity. One week and 8 weeks after transplantation, DAPI-labeled cells were observed in the heart of the recipient rats, but not in the hearts of control rats. One week after transplantation, ultrastructural observation identified a small number of cells in the peripherals of the infarct area of the recipient rats with similar morphology to that of MSCs cultured in vitro. At 8 weeks,a large number of capillaries were seen in the ischemic myocardium on the peripheral of the infarct area. Ultrastructural observation also revealed some immature myocytes surviving in the ischemic region. CONCLUSION: MSCs is capable in vivo of homing to the ischemic myocardium via the blood circulation, and promote regeneration of the myocardium and blood vessels.

Animals↗
PubMed2005

[Effects of 100 Hz vibration on ultrastructure of soleus muscle in tail-suspended rats].

OBJECTIVE: To study the effects of 100 Hz vibration on ultrastructure of intrafusal and extrafusal fibers in soleus muscle of tail-suspended rats. METHOD: Weightlessness was simulated by tail suspension of female rats. The ultrastructure of intrafusal and extrafusal fibers of soleus muscle were examined after exposure to 100 Hz vibration. RESULT: The ultrastructure of intrafusal and extrafusal fibers of soleus muscles showed obvious retrograde changes after 7 d tail suspension, whereas these changes were not obvious after 7 d tail suspension plus 100 Hz vibration. CONCLUSION: High frequency vibration can counteract the effect of simulated weightlessness on ultrastructure of intrafusal and extrafusal fibers in soleus muscles of rats.

Animals↗
PubMed2005

Sneddon's syndrome as a disorder of small arteries with endothelial cells proliferation: ultrastructural and neuroimaging study.

We report a 18-year-old female patient with livedo reticularis and neurological disturbances. CT scan showed two big ischemic focuses in the pons, moreover MRI revealed small disseminated ischemic focuses in the pons and deep structures of both brain hemispheres. MRA demonstrated no changes in the big extracranial and intracranial arteries. Since the clinical data and neuroimaging results suggested Sneddon's syndrome, the skin and skeletal muscle biopsy was taken to examine. The immunohistochemical and ultrastructural investigations of the skin biopsy revealed a significant reduction of the lumen of the capillaries and small to medium-sized arteries. Cells surrounding the vascular lumen, frequently with multilayer arrangement and their nuclei placed perpendicularly to the lumen, were CD31, CD34, and sporadically SMA positive. At the ultrastructural level, these proliferating cells showed typical features of endothelial cells: abundant intermediate filaments and Weibel-Palade bodies. Between the endothelial cells some junctions were detached as well in the capillaries as in the small arteries. The smooth muscle cells of the small arteries were electron denser than usual and their cytoplasmic protrusions penetrated to the endothelial cells. The ultrastructural picture of some vessels with a considerably narrow lumen was typical of vessels newly formed during angiogenesis. Neuroimaging including TC, MRI, MRA besides histological, immunohistochemical and ultrastructural evaluation may be useful for diagnosis of Sneddon's syndrome.

Adolescent↗
PubMed2005

The myofibroblast: a study of normal, reactive and neoplastic tissues, with an emphasis on ultrastructure. part 2 - tumours and tumour-like lesions.

This paper describes the ultrastructure of the commoner myofibroblastic tumours and tumour-like lesions. The objective is to complement mainstream pathology texts, which have concentrated on the clinical and light microscopy features of these lesions and which have arguably but understandably somewhat neglected electron microscopy as an ancillary diagnostic tool and a technique for investigating tumour cell biology. Ultrastructural features are described of nodular fasciitis, the myofibromatoses (including Dupuytren's disease), inflammatory myofibroblastic tumour, post-operative spindle cell nodule, fibroma of tendon sheath, fibrous pseudotumour, benign fibrous histiocytoma, atypical fibroxanthoma, dermatofibrosarcoma protuberans, myofibrosarcoma (myofibroblastic sarcoma), malignant fibrous histiocytoma (pleomorphic myofibrosarcoma), epithelioid sarcoma and spindle-cell carcinoma. Fibrosarcoma and leiomyosarcoma are illustrated for comparison. The fibronexus is emphasised as an important marker for the most confident diagnosis of myofibrosarcoma. Some pathologists accept a light microscope definition, which includes alpha-smooth-muscle actin positivity, h-caldesmon negativity and, in some cases, desmin positivity. Caution in the interpretation of desmin staining in a possible myofibroblastic lesion is urged, since, in combination with an ultrastructurally identified lamina, it more probably suggests true smooth-muscle differentiation. Myofibroblastoma and angiomyofibroblastoma are examples of tumours argued on the basis of ultrastructural findings (sometimes in combination with desmin staining) to be primitively differentiated smooth-muscle cell rather than myofibroblastic proliferations.

Adolescent↗
PubMed2006

[Ultrastructural changes of the rat convoluted seminiferous tubule-after alcohol consumption].

OBJECTIVE: To study the ultrastructural changes of the rat convoluted seminiferous tubule after alcohol consumption. METHODS: Forty-eight Wistar mature male rats were divided into two groups randomly: control group (A) and experimental one (B). 6 ml/(kg x d) of 50 degrees alcohol was perfused through the gastric tube for 39 days in Group B; and 6 ml/(kg x d) of normal saline was supplemented in Group A. The ultrastructure of the rat convoluted seminiferous tubule was observed by transmission electron microscope at day 14, 27 and 40. RESULTS: In Group A, the pykno-basement membrane was unstriated and uniform, Sertoli cells showed cytoplasmic profusion, with big nucleus, well-distributed nucleoplasm, distinct nucleolus, more mitochondria and plain hierarchical tight-junction. And the ultrastructure of the rat convoluted seminiferous tubule in Group B began to change at the end of the first spermatogenic cycle (D 14) and changed more and more evidently with the ethanol administration, mainly as follows: (1) more lysosomes and vacuolisation found in Sertoli cells, and organelles decreased and blurry; (2) more and bigger vacuoles among the spermatogonia, Sertoli cells and basement membrane; (3) obvious apoptosis of spermatogonia and apoptotic bodies aggregated near the membrane; (4) more cytoplasm and vacuolisation in the sperm of the convoluted seminiferous tubule, and disarranged, deleted or clustered mitochondria in the sperm tail; (5) blurry and rigid tight-junction; (6) thickened, wrinkled or broken basement membrane and under-basement CONCLUSION: Alcohol can cause ultrastructural changes of the basement membrane, tight-junction and Sertoli cells of the membrane. rat convoluted seminiferous tubule and apoptosis of spermatogonia.

Animals↗
PubMed1990

Ultrastructural and electron-immunocytochemical characterization of cells in epiretinal membranes.

Electron-immunocytochemical staining for three intermediate filament (IF) proteins, keratin (K), glial fibrillary acidic protein (GFAP), and vimentin (V), and for the macrophage marker, EBM/11 (E), was performed on epiretinal membranes obtained during vitrectomies performed for proliferative vitreoretinopathy (PVR), postdetachment macular puckers (PDMPs), idiopathic macular puckers (IMPs), or macular puckers associated with other disease processes. The ultrastructural and immunocytochemical characteristics of the cells were compared. Unstained cells outnumbered stained cells for each of the markers in almost all membranes. Six cell types, based on ultrastructure, were found in the majority of epiretinal membranes: 1) polarized cells with microvilli on the free border and foot processes anchoring them to extracellular matrix that consistently stained negative for all of the immunocytochemical markers; 2) spindle-shaped fibroblastlike cells that were generally negative for all markers, but rarely positive for V; 3) large undifferentiated cells with large, lightly stained nuclei and little cytoplasm that frequently expressed one of the intermediate filament (IF) proteins; 4) poorly differentiated cells that contained numerous mitochondria and frequently expressed one of the IF proteins; 5) undifferentiated, pigment-laden cells that rarely stained for any of the above IF proteins, but occasionally showed K or V positivity in a portion of the cell, suggesting that they may be losing or acquiring these proteins, and that rarely expressed GFAP; and 6) small, round, mononuclear cells with short processes that were sometimes, but not always, positive for E and that were consistently negative for K, V, and GFAP. In addition to these morphologic types, transitional cells demonstrating features of two or more of the above cell types were seen, suggesting that phenotypic changes between the various cell types can occur. The amount of extracellular matrix in epiretinal membranes showed a correlation with disease process (PVR greater than PDMP greater than IMP), and a negative correlation with the percentage of cells expressing a highly differentiated polarized morphology and with the percentage of cells staining for IF proteins. These data suggest that both cell morphology and IF protein expression may be dependent in part on microenvironment and that neither alone can be used to identify unequivocally the derivation of particular cells found in epiretinal membranes. The integration of ultrastructural and immunocytochemical data may provide a more accurate determination of the cell of origin and of phenotypic changes that have occurred. In some cases, however, both ultrastructural and IF protein composition taken together are insufficient for the precise identification of all cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2006

Effects of hydrogen peroxide bleaching strips on tooth surface color, surface microhardness, surface and subsurface ultrastructure, and microchemical (Raman spectroscopic) composition.

OBJECTIVE: This study examined the effects of hydrogen peroxide tooth bleaching strips on the surface hardness and morphology of enamel and the ultrastructure and chemical composition of enamel and dentin in vitro. METHODOLOGY: Sound human molars were ground and polished to prepare a uniform substrate for bleaching treatments. A cycling treatment methodology was employed which alternated ex vivo human salivary exposures with bleaching treatments under conditions of controlled temperature and durations of treatment. Bleaching treatments included commercial Crest Whitestrips bleaching strips, which utilize hydrogen peroxide in a gel as the in situ bleaching source at 6.0 and 6.5% concentrations of H2O2. Control treatments included an untreated group. Crest Whitestrips bleaching included treatment exposures simulating 2x the recommended clinical exposures (28 hours bleaching). Surface color measurements were taken prior to and following bleaching to ensure tooth bleaching activity. The effects of bleach on physical properties of enamel were assessed with microhardness measures. Ultrastructural effects were classified by surface and subsurface confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) techniques. In addition, the effects of bleaching on tooth microchemical composition was studied in different tooth regions by coincident assessment of Raman spectroscopic signature. RESULTS: Color assessments confirmed significant ex vivo tooth bleaching by Whitestrips. Surface microhardness and SEM measures revealed no deleterious effects on the enamel surfaces. CLSM micromorphological assessments supported the safety of hydrogen peroxide bleaching strips both on surface and subsurface enamel, DEJ, and dentin ultrastructure. Raman spectroscopy analysis demonstrated no obvious effects of bleaching treatments on the microchemical composition of enamel and dentin. CONCLUSION: These results confirm that tooth bleaching with hydrogen peroxide whitening strips does not produce changes in surface/subsurface histomorphology or in surface microhardness and ultrastructure of treated teeth. In addition, for the first time, these results confirm the safety of hydrogen peroxide bleaching strips to tooth microchemical composition as measured by Raman spectroscopy.

Dental Enamel↗
PubMed1990

Ultrastructural and immunocytochemical changes in retinal pigment epithelium, retinal glia, and fibroblasts in vitreous culture.

Retinal pigment epithelial (RPE) cells, retinal glial, and fibroblasts, three cell types believed to play a role in the pathogenesis of epiretinal membrane formation, were maintained in vitreous culture to determine the influence of vitreous on their ultrastructure and expression of cytokeratin, glial fibrillary acidic protein (GFAP), vimentin, and glutamine synthetase (GS). Using a highly sensitive, preembedding technique for the immunolocalization of these antigens at the ultrastructural level, most RPE cells were found to lose cytokeratin and vimentin within 1 day after seeding on irradiated vitreous. The percentage of keratin-positive cells then increased with time in culture. If the vitreous was placed on RPE cells cultured in monolayer instead of placing the cells on the vitreous, keratin and vimentin were expressed these intermediate filament proteins diminished with time. Glutamine synthetase was found in RPE cells grown in monolayer with or without a vitreous overlay, but not in RPE cells grown on the surface of vitreous. Retinal glial grown on vitreous showed a time-dependent decrease in the number of cells expressing GFAP and a corresponding increase in cells expressing vimentin or GS. Some fibroblasts in vitreous culture expressed vimentin but not the other antigens evaluated. A substantial number of cells in each culture did not stain positively for cytokeratin, GFAP, vimentin, or GS. All three cell types showed phenotypic diversity at the ultrastructural level with each cell type being capable of assuming the same morphologic appearance under certain conditions. These results demonstrate the phenotypic plasticity of RPE cells, retinal glia, and fibroblasts when grown in contact with vitreous and provide further evidence that neither ultrastructure, intermediate filament protein expression, nor the presence of GS is sufficient to determine the cell type of origin of cells in epiretinal membranes.

Animals↗
PubMed1975

The ultrastructure of smooth muscle tumors with a consideration of the possible relationship of glomangiomas, hemangiopericytomas, and cardiac myxomas.

Tumors classified as being of smooth muscle origin by light microscopy were studied with the electron microscope. Their ultrastructure verified the diagnosis in all of the seven leiomyomas but in only eight of the twelve (66 percent) tumors that were finally classified as leiomyosarcoma. The discrepancy of the light microscopic and ultrastructural findings in these four sarcomas may be due to sampling problems likely to be encountered in poorly differentiated tumors or simply the failure of development of specific ultrastructural features in the face of a characteristic growth pattern at the light microscopic level. Among other tumors that have been considered to be of smooth muscle origin--hemangiopericytoma, glomangioma, and cardiac myxoma--only the glomangioma showed ultrastructure features identical to those of smooth muscle.

Adolescent↗
PubMed1977

[Pathomorphologic studies of the endocrine cells in the gastrointestinal mucosa. Physiology, cytochemistry and ultrastructure (author's transl].

With combined immunofluorescent, cytochemical and electron microscopic investigations the enterochromaffin cell system has been differentiated into 5 distinct endocrine cell types in the human stomach and into 8 cell types in the intestine. These endocrine cells are probably of neuroectodermal origin and belong to the APUD (amine precursor uptake and decarboxylation)-system. Maximal gastrointestinal hormone concentrations as determined by tissue extracts correlate fairly well to the location of each endocrine cell type in various segments of the gastrointestinal tract. In certain gastroenteropathies the pathophysiological disturbances can be explained by pathomorphological alterations of the disseminated endocrine cells. 1. The gastrin-producing G-cell is the predominating endocrine cell in the gastric antrum. Besides immunocytochemistry the G-cell can be demonstrated with argyrophilic reaction (Grimelius, 1968), masked metachromasia and leadhematoxylin. The ultrastructural features are variable, depending on functional activity. The secretory granules are usually only slightly osmiophilic, measuring 200 till 250 nm in diameter. By some working groups a positive immunofluorescence with gastrin-antisera has been demonstrated in A1- or D-cells of the pancreatic islets. However, numerous negative results have been reported, too. Considering physiological conditions, a gastrin-secretion of the human pancreatic islets has not been secured without doubt. 2. The EC-cell produces serotonin and in the intestine motilin, too. Besides the formaldehyde-induced fluorescence, these cells can be demonstrated with diazonium and argentaffin reactions, less specific with argyrophilic methods. Ultrastructurally the EC-granules are easily differeniated from the other endocrine cells by their pronounced osmiophilia and pleomorphism. In experimental conditions the EC-cells demonstrate species- and site-specific alterations. With reserpine no ultrastructural changes were demonstrable in EC-cells of the rat. However, marked ultrastructural alterations with an increase of the hormone-producing organelle system were noticed after administration of parachlorophenylalanine (PCPA) which interferes with serotonine synthesis; 5. The gastric D-cells are characterized by large secretory granules similar to pancreatic D-cells. They secrete the HCl-inhibitory peptide somatostatin. 4. The D1-cell is a cell type with unknown function. The cytoplasm contains small granules with variable electron density. According to most authors, they represent a distinct cell type and not just a variant of the G-cells. It may be very difficult, however, to separate certain forms of D1-cells from functionally altered G-cells. 5. The A-cell can be found in the gastric mucosa of certain animal species, where it has been demonstrated by immunocytochemistry with antisera to gut-glucagon. This cell type does not occur in the human gastric mucosa. 6...

Adenoma, Islet Cell↗
PubMed1977

Effect of polychlorinated biphenyl (PCB) on the thyroid gland of rats. Ultrastructural and biochemical investigations.

Polychlorinated biphenyls (PCB) produced ultrastructural lesions in thyroid follicular cells and reductions in serum thyroxine levels in rats that were time- and dose-dependent. The acute effects (4 week) of PCB (50 and 500 ppm) consisted of an accumulation of lysosomal bodies and colloid droplets in follicular cells with abnormalities of microvilli on the luminal surface. The chronic administration (12 week) of PCB (50 and 500/250 ppm) resulted in a striking distention of many follicular cells with large lysosomal bodies with strong acid phosphatase activity and colloid droplets, blunt and abnormally branched microvilli, and mitochondrial vacuolation. These ultrastructural alterations in follicular cells were associated with a highly significant reduction in serum thyroxine with both the low and the high dose of PCB. Follicular cells remained responsive to the lowered thyroxine level after feeding PCB for 4 and 12 weeks and underwent moderate compensatory hypertrophy and hyperplasia. Thyroid follicles were smaller than in controls and were lined by more columnar cells that occasionally formed papillary projections into the colloid. Residual ultrastructural alterations persisted for 12 weeks following cessation of feeding the compound, and serum thyroxine levels were significantly lower than in control rats. However, 35 weeks after discontinuing PCB, thyroid follicular cells were similar to those in controls and serum thyroxine levels had returned to normal. The striking ultrastructural lesions in follicular cells produced by feeding PCB to rats appeared to contribute to the lowering of serum thyroxine levels, in combination with the known stimulation of peripheral thyroxine metabolism by these compounds. Certain metabolic alterations produced by PCB intoxication in experimental animals and human beings may be related to an alteration in thyroid function.

Animals↗
PubMed1991

The correlation between magnetic resonance imaging and ultrastructural patterns of brown adipose tissue.

The present paper reports on magnetic resonance imaging (MRI) at high spatial resolution of the brown adipose tissue (BAT) in laboratory rodents, in comparison with light and electron microscopy findings. Our aim was to assess whether MRI correlates with the expected ultrastructural differences between newborn and adult BAT. The study was performed on the cervical and the interscapular BAT deposits by means of a nuclear magnetic resonance (NMR)-spectrometer equipped with a high resolution imaging system. Ultrastructural examination of BAT at different ages showed three different patterns of adipocyte ultrastructure in BAT which were associated with different MRI patterns. In BAT, MRI identifies the prevalent type of adipocyte in the tissue providing information consistent with ultrastructural results. Results presented here show that MRI represents a precise and reliable tool to investigate the morphology of tissues in living animals. The safe, non-invasive MRI technique represents a very useful tool in morphological research.

Adipose Tissue, Brown↗
PubMed1990

[Infiltrative and cytolytic activities of lymphokine-activated killer (LAK) cells against a human glioma mass: ultrastructural analysis using a three-dimensional multicellular spheroid model].

In the present study, we have investigated not only the infiltrative and cytotoxic activities of lymphokine-activated killer (LAK) cells on a tumor mass, but also the ultrastructural cell-to-cell interaction between LAK effector cells and target tumor cells during the cytolytic process within a three-dimensional solid tumor. A multicellular tumor spheroid (MTS) of a human malignant glioma cell line (U-251MG) was utilized as a solid tumor model. LAK cells were generated from peripheral blood lymphocytes (PBL) of a healthy donor after 4-day culture in the presence of interleukin-2 (IL-2). MTSs of 500 microns diameter were cocultivated with either LAK cells or non-activated PBL, and then time-sequential kinetic, morphological, and ultrastructural examinations were carried out. It was demonstrated that the number of viable tumor cells present within MTSs gradually decreased in parallel with the increase in the number of LAK cells. Morphological analyses revealed that LAK cells directly infiltrated toward the inner areas of MTSs and caused a progressive tumor destruction. In contrast, PBL hardly exhibited such activities. Ultrastructurally, it was found that the infiltrating LAK effector cells were composed of heterogeneous subpopulations, T-like cells and large granular lymphocyte (LGL)-like cells, and that both types of lymphocytes tightly adhered to the tumor cells and extended their cytoplasmic extensions deeply into the targets which underwent a progressive degeneration. Concerning the cellular interaction, it was found that these two kinds of LAK cells displayed some distinct ultrastructural feature in the process of target cell killing. Particularly, it should be stressed that LGL-like LAK cells exhibited a significant development of the intracytoplasmic secretory granules, suggesting an association with the lethal hit of target cell lysis.

Brain Neoplasms↗
PubMed1990

Heterozygous expression of Lesch-Nyhan syndrome clinical and ultrastructural studies.

The study comprised two cases (male & female sibs) from one family, with Lesch-Nyhan Syndrome. They were subjected to clinical evaluation, pedigree construction, uric acid estimation in blood, urates in urine, metabolic screening of blood and urine for amino acids, examination of oral cavity, histological studies of the gingiva by light and electron microscopy as well as buccal smear for Barr & Y bodies (for the female). The proband, a six years old female presented with self-mutilation, mental retardation, hyperactivity and aggression. She had bitten her index finger causing amputation of its distal phalanx. On family study her younger brother (9 months) was found to have increased uric acid and less severe neurologic involvement. The serum uric acid level of the affected female was higher. Her Barr body showed normal pattern. Oral cavity examination showed no abnormalities. Histological examination of the gingiva showed macrophages around the blood vessels. Ultrastructural studies showed more or less normal epithelium. There was collection of macrophages around the blood vessels in the sub-epithelial layer, the cytoplasm of these macrophages contained stippled cytoplasmic inclusions. The surrounding connective tissue showed thin collagen fibers with sharp delineation between the epithelial and connective tissue layers indicating poor quality of collagen. There was no histological difference between the hemizygous male and the heterozygous female. The present study indicates heterozygous expression of Lesch-Nyhan Syndrome at both the clinical and the ultrastructural levels in favour of extreme lyonization or X-chromosome deletion in the affected female. Our findings also indicate that ultrastructural studies could be sensitive indicators of abnormal uric acid metabolism. Further studies are needed to compare the phenotypic expression of hemizygotes and heterozygotes with Lesch-Nyhan Syndrome at both the clinical and ultrastructural levels.

Child↗
PubMed1990

Ultrastructural changes of the substantia nigra, ventral tegmental area and striatum in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice.

The substantia nigra pars compacta (SNc), ventral tegmental area (VTA) and striatum in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated young adult mice were examined for the occurrence of marked ultrastructural changes. In the median SNc dopaminergic neurons, the Golgi apparatus and rough endoplasmic reticulum were dilated and there was a decrease in the number of ribosomes in the rough endoplasmic reticulum (Nissl substance). The mitochondrial cristae were often disarranged. Characteristic electron dense deposits were often observed in the neuronal fibers, many of which were dilated. However, no clear evidence of nuclear degeneration was seen. On the other hand, ultrastructural abnormalities were not seen in the dopaminergic neurons in the VTA. In both the latero-dorsal and latero-ventral striatum, many dilated neuronal fibers, which contained only a few synaptic vesicles and sparse subcellular structures were observed, but no significant ultrastructural changes could be seen in the medial part of the striatum in MPTP-treated mice. Thus, the effect of MPTP treatment is inhomogenous within the mouse striatum, as would be expected from the appearance of ultrastructural changes in only some of the dopaminergic neurons in the SNc.

Animals↗