• Journal of the Korean Wood Science and Technology
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• v.34 no.5
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• pp.1-10
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• 2006

The objective of this study was to elucidate the microscopic patterns of decay caused by brown-rot fungi of Tyromyces palustri and Gloeophyllum trabeum in Korean red pine (Pinus densiflora) and radiata pine (Pinus radiata) woods through light and electron microscopies. The ultrastructural changes of cell walls attacked by the two brown-rot fungi were compared in this respect. Macroscopically, radiata pine showed more ring and radial checks than Korean red pine. Microscopically, with the progress of decay, spiral checks associated with cross-field pits and bore holes in the cell wall were more remarkably numerous in the radiata pine than in the Korean red pine. In the radiata pine, G. trabeum produced more spiral checks in the cell wall than T. palustris. In the advanced stages of decay by G. trabeum, the erosions of ray cell walls were identified both in the Korean red pine and radiata pine but $S_3$ layers of tracheid walls were eroded only in the Korean red pine.

• Progress in Medical Physics
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• v.33 no.4
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• pp.158-163
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• 2022

Purpose: We subjected scanning electron microscopic (SEM) images of the active layer of EBT3 film to texture analysis to determine the dose-response curve. Methods: Uncoated Gafchromic EBT3 films were prepared for direct surface SEM scanning. Absorbed doses of 0-20 Gy were delivered to the film's surface using a 6 MV TrueBeam STx photon beam. The film's surface was scanned using a SEM under 100× and 3,000× magnification. Four textural features (Homogeneity, Correlation, Contrast, and Energy) were calculated based on the gray level co-occurrence matrix (GLCM) using the SEM images corresponding to each dose. We used R-square to evaluate the linear relationship between delivered doses and textural features of the film's surface. Results: Correlation resulted in higher linearity and dose-response curve sensitivity than Homogeneity, Contrast, or Energy. The R-square value was 0.964 for correlation using 3,000× magnified SEM images with 9-pixel offsets. Dose verification was used to determine the difference between the prescribed and measured doses for 0, 5, 10, 15, and 20 Gy as 0.09, 1.96, -2.29, 0.17, and 0.08 Gy, respectively. Conclusions: Texture analysis can be used to accurately convert microscopic structural changes to the EBT3 film's surface into absorbed doses. Our proposed method is feasible and may improve the accuracy of film dosimetry used to protect patients from excess radiation exposure.

• Applied Microscopy
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• v.28 no.4
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• pp.447-463
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• 1998

This study was carried out to investigate the histomorphological changes and the electrophoretic patterns of egg components, obtained from 100 of 2-year-old female catfishes (Silurus asotus). Female Korean catfishes collected in the vicinity of Chollabukdo have synchronous ovaries which discontinously ovulate eggs during the breeding season (from late May until early July). The fishes were killed by severing the spinal cord just posterior to the head after immobilization with tricaine methanesulfonate (MS 222). Especially, the light microscopic and ultrastructural changes of ooplasm and follicular membranes of oocytes, were examined by means of light and transmission electron microscopy. The size of the nucleoli and number of the yolk granules increased as the oocyte groved. Yolk granules were deposited in the oocyte as fluid Due to tile presence of large early and late maturing oocytes, their ovaries were enlarged, transparent, granular and greenish in color. As the percentages of fish in late maturing oocyte (LMO) and ripe oocyte (RO) stage increased from March to April, mean gonadosomatic index (GSI) values (19.95%) increased. Zona radiata changed from squamous into cuboid in shape in the early maturing oocyte (EMO) stage. Processes, microvilli, from the zona radiata and from the oocyte grow, and make contact with each other in the pore canals of the zona radiata during vitellogenesis, but are withdrawn as the zona radials becomes more compact and devoid of pore canals during oocyte maturation. Seasonal changes in the microscopic appearance of the ovaries were well correlated with those in both gonadosomatic index and macroscopic appearance. The main cytological changes such as increase in size of cell, nucleus, nucleolus, and increase in number of nucleoli and mitochondria demonstrated with electron microscopy in the previtellogenic oocytes of Korean catfish, provided evidences for important synthetic processes in an early preparatory phase of oocyte development. The electrophoretic pattern of major band in mature stage was much thicker (24 k, 66 k, 90-110k dalton) than that in previtellogenic phase.

• Radiation Oncology Journal
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• v.7 no.2
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• pp.157-169
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• 1989

Radiological and clinical evidences indicate that hyperthermia combined with irradiation produce a significant improvement in therapeutic effect of cancer The experiences obtained from 90 rats' kidney A single dose of irradiation ranged from 6Gy, 8Gy and 10Gy was delivered on the rat's kidney. The combined therapy group had the same irradiation after hyperthermia at $42\~44^{\circ}C$ for 30 minutes. Microscopic examination and calculation of thermal enhancement ratio were carried out, and the results were as follows: 1. In the group of hyperthermia alone, there were moderate glomerular congestion and mild tubular degeneration on light microscopic examination. 2. In the group of irradiation alone, tubular degeneration was noted in 6Gy irradiation and its severity was increased along with radiation dose. 3. In the group of hyperthermia combined with irradiation, tubular degeneration and necrosis were appeared in 6Gy and 10Gy irradiation, respectively. 4. On electron microscopic examination, proximal convoluted tubular and glomerular changes in irradiation group were similar to that of combined with hyperthermia, and its severity was increased along with observation periods. 5. Thermal enhancement ratio (TER) was 1.0 after evaluation of histipathologic changes in rat's kidney, with combination therapy.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.26 no.2
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• pp.75-90
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• 1996

The purpose of this study was to observe microscopic change of salivary gland tissue, which is a cause of xerostomia in diabetic condition; for this target, the author injected streptozotocin 0.1ml/100 gm b.w. on the rat, Sprague Dawley, to induce diabetes, and then observed microscopic changes in parotid gland tissue using light microscopy and electron microscopy. The results were as follows : 1. Parotid gland tissue of the diabetic rat was atrophied or degenerated in lapse of experimental time, but began to repair from 14 days after diabetic induction. 2. In the basal lamina of the vessel of parotid gland tissue in the diabetic rat, lamina lucida was discontinued and lamina densa was increased in thickness, but the number of capillary was gradually increased and dilated. 3. In acinic and intercalated ductal cells of parotid gland in the diabetic rat, changes of mitochondria, RER, secretory granule, free ribosome were prominent. In conclusion, the present study demonstrated that degenerative changes of the parotid gland tissue were due to not completely thickening of the basal lamina of vessels, but many other causal factors, because thickness of the basal lamina of vessels was not related with degenerative changes.

• Parasites, Hosts and Diseases
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• v.23 no.1
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• pp.47-58
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• 1985

An experimental study was performed to observe the in vivo effects of praziquantel on the light and scanning electron microscopic morphology of Fibricola seoulensis. The metacercariae were obtained from the snakes and 1, 000 in each number was orally given to total 15 albino rats; 5 controls and 10 treatment group. Seven days later the 10 rats were treated with 10 mg/kg praziquantcl and sacrificed 1~24 hours later to search for the worms from their small intestines. The major light microscopic changes in the drug-exposed worms were early contraction followed by relaxation of especially their forebody, vacuolization of the tegument and subtegumental parenchymal layers, and narrowing of the intestinal lumens. The scanning electron microscopic findings were characterized by formation of numerous blebs followed by rupture and subsequent destruction of their whole teguments. These results show that the change in worm body is not confined to the tegument but extends to deeper parenchymal portions and also occurs in their intestines. It is suggested that the drug uptake by the worms should be either through their tegument or through the digestive tract.

• Applied Microscopy
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• v.3 no.1
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• pp.45-54
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• 1973

The present study is to determine the toxicity of the fungi isolated from foodstuffs by observing the ultrastructural changes in the mouse liver cells. The results as follows: 1. The toxin-producing fungi were screened by the methods of toxin-screening test(cyto-toxicity test against to HeLa cells and thin layer chromatography). 2. All of the experimental animals treated with isolated fungi were observed the focal necrosis and inflammatory infiltration of liver parenchymal cells. 3. It showed the cytoplasmic changes, such as dilatation of rough endoplasmic reticulum (RER), swelling of mitochondria (mi). increased number of lipid droplet (li) and glycogen (gl), detachment of ribosomes (ri) by observing the electron microscopy. 4. Nuclear and nucleolar alteration were also noted the segregation of nucleolar element and irregularity of nuclear envelopes. 5. As a mass screening, the cytotoxicity test using HeLa cells and thin layer chromatography are feasible methods to detection of the mycotoxin producing fungi from various sources.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.18 no.1
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• pp.137-147
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• 1988

This study was designed to investigate the effects of irradiation on the salivary ductal cells, especially on the intercalated ductal cells of the rat parotid glands. For this study, 36 Sprague-Dawley strain rats were irradiated on the head and neck region with absorbed dose of 15Gy by Co-60 teletherapy unit, Picker's model 4M60. The conditions irradiated were that field size, SSD, dose rate and depth were 12×5㎝m, 50㎝, 222 Gy/min. and 1㎝. respectively. The experimental animals were sacrificed 1, 2, 3, 6, 12 hours and 1, 3, 7 days after the irradiation and the changes of the irradiated intercalated duct cells of the parotid glands were examined under the light and electron microscope. The results were as follows: 1. Under the light and electron microscope, the nucleus, mitochondria and secretory granules showed severe changes in the early stage after irradiation and the most severe cellular de- generations were observed 2 hours after irradiation, but the repair processes began from 6 hours after irradiation. 2. Under the electron microscope, loss of the nuclear membranes, derrangement of the chromosomes, swelling and destruction of the secretory granules, and widening of the intercellular spaces were observed after irradiation. 3. Under the light microscope, atrophy and irregular proliferation of the ductal cells, cuboidal metaplasia, hyperchromatism, and the construction or obstruction of the lumen were observed after irradiation.

• Korean Journal of Veterinary Research
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• v.29 no.4
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• pp.531-540
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• 1989

A new sudden death in rabbits appeared in China and Korea in 1984 and 1985, respectively, and was recognized to be an acute infectious disease caused by a virus. The disease was reported as a "new viral disease," and thereafter, a tentative name of "viral hemorrhagic disease", "hemorrhagic pneumonia" or "viral hemorrhagic pneumonia" has been described in the case reports. But authors had called the viral disease "rabbit viral hepatitis" due to picornavirus infection, because the principal lesion of the disease was an acute hepatitis. The purpose of this report is to describe the electron microscopic findings on the livers in experimentally infected rabbits. All the livers of the affected rabbits were shown to have degenerative changes of a type that is characteristic of acute hepatitis. In the liver cells, there were dilation of rER and mitochondria, vacuole formation of various sizes, and appearances of many virus-like particles in the vicinity of rER, granular bodies and crystalline arrays of viral particles in the cytoplasm with necrotic changes of the nucleus. Clusters of virus-like particles and viral crystals appeared in the cytoplasm of sinusoid endothelial cells and Kupffer's cells with morphological changes of organelles. Also viral crystals were demonstrated in the cytoplasm of macrophages among the liver cells. On the whole, the liver cells had many virus-like particles and a few crystalline arrays of viral particles. Therefore, this implies that the liver cells are the main site of the viral replication in inducing the viremia. It was concluded that the liver was the primary target organ of this viral disease, and the pathological and the ultrastructural evidence suggest that the virus may be belong to genus enterovirus.

• The Journal of the Korean Society for Microbiology
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• v.10 no.1
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• pp.39-58
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• 1975

These studies were carried out to detect the presence of mycotoxin producing fungi in various kind of grains and foodstuffs in Korea. The experiments were divided into three parts: bacteriologic, toxicologic and electron microscopic studies. The results were summarized as follows: 1. From the 133 various samples, 426 colonies of fungi were isolated. In 405 of 426 colonies, it was possible to identify 17 genera. Among the identified strains, the predominant genera were Penicillium, Aspergillus and Alternaria. 2. In cytotoxicity test, 20 strains showed mild to severe toxic effects in mice and 24 strains showed toxic effects on HeLa cells among the 107 strains of experiments. 3. In electron microscopic studies of liver cells from animal which had been treated with toxin like substances, the liver cells showed the cytoplasmic changes: dilatation of endoplasmic reticulum, swelling of mitochondria, disappearance of mitochondrial cristae, increased number of lipid and glycogen particles. Nucleus and nuclear envelope alterations were also noted. 4. In fine structure of HeLa cells treated with culture filtrates of mycotoxin producing fungi and experimental strains had been noted a certain specific changes induced by culture filtrates. These alterations showed the disappearance of golgi complex, endoplasmic reticulum vacuolization and mitochondrial changes. 5. As a mass screening, the cytotoxicity tests of HeLa cells and histopathologic study of mice liver cells treated with toxin-like substances, employed are feasible to detect mycotoxin producing fungi.