• The Korean Journal of Nuclear Medicine
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• v.36 no.1
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• pp.80-86
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• 2002

Presently, PET is widely used in oncology, but suffers from limitations of poor anatomical information. To compensate for this weakness, a combined PET/CT has been developed by Professor Townsend at the University of Pittsburgh Medical Center. The prototype was designed as PET and CT components combined serially in a gantry. The CT images provide not only accurate anatomical location of the lesions but also transmission map for attenuation correction. More than 300 cancer patients have been studied with the prototype of PET/CT since July, 1998. The PET/CT studies affected the managements in about $20{\sim}30%$ of cancer patients. These changes are a consequence of the more accurate localization of functional abnormalities, and the distinction of pathological from normal physiological uptake. Now a variety of combined PET/CT scanners with high-end PET and high-end CT components are commercially available. With the high speed of multi-slice helical CT, throughput of patient's increases compared to conventional PET. Although some problems (such as a discrepancy in breathing state between the two modalities) still remain, the role of PET/CT in oncology is very promising.

• Journal of Life Science
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• v.11 no.2
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• pp.111-120
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• 2001

The pathological aspects of purified ricin from the seeds of the castor oil plant, Ricinus communis, were examined, using light and transmission electron microscopy. ICR mice were exposed to ricin by peritoneal injection with 100 ng/1 $m\ell$ PBS(pH 7.0) mouse and histological observations on the liver, spleen, thymus, lung and heart were carried out at intervals up to 48 h after exposures. All the organs examined were damaged by ricin. Among the organs, the spleen and thymus; immune organs were the most sensitive to ricin, whereas the effect delayed in the liver, lung and heart. Furthermore, the immune cells in each organ were the most sensitive to ricin. Accordingly, the effect of ricin on the organs seems to be affected by the immune cells existed in each organ, In each organ, the immune cells showed apoptotic changes, while the capillary endothelial and parenchymal cells showed necrotic changes.

• International Journal of Industrial Entomology and Biomaterials
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• v.21 no.1
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• pp.117-125
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• 2010

The tropical tasar silkworms, Antheraea mylitta (D) produce famous silk 'Kosa' in central part of India. Due to outdoor rearing it became susceptible to viral infection including cytoplasmic polyhedrosis virus (CPV). The common mode of entry of cytoplasmic polyhedrosis virus is per os and cause gresserie disease to the larvae. Histopathological studies elucidated the insect CPV virus produces infective polyhedral inclusion bodies (PIBs) in the midgut cell cytoplasm of virus infected fifth instar larvae. The PIBs multiply enormously in the cytoplasm without invading the nucleus. Ultrastructural studies confirmed the pathological effects of CPV on in midgut cell cytoplasm. The multiplication of polyhedral inclusion bodies took place into the vacuoles and form virogenic stromata in the cytoplasm of cells. However, the encapsulations of polyhedral inclusion bodies into the polyhedrin protein occurred and polyhedra were released into the lumen. At the late stage of infection, cells showed the regressed cytoplasmic organelles with large vacuoles and elongated mitochondria. Hence, the horizontal transmission of CPV causing the midgut cells disintegration in the tasar silkworm, Antheraea mylitta (D) confirmed during infection.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.4
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• pp.263-273
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• 2010

Occupational exposure to wollastonite can occur during its mining, processing and using. Wollastonite was analyzed for its physicochemical properties by transmission electron microscope and scanning electron microscope equipped with energy dispersive X-ray spectrometer. Wollastonite fibers were 3.3${\mu}m$ in diameter(av.) and were 30.5${\mu}m$ in length(av.). The atomic composition of wollastonite was Si 56.41% and Ca 43.59%. Respiratory toxicity of wollastonite has been studied in term sequential in Sprague-Dawely rats. UICC chrysotile (average diameter 0.03${\mu}m$, average length 2.93${\mu}m$) was applied as the positive control. The effects of 2mg wollastonite on respiratory system and pathological changes were evaluated after 1, 4, 8, 12 weeks instilled into rat lungs. Inflammation response broke out from 1 week after instilled with wollastonite and the pathological examination further showed increased legions of granulomatous inflammation after 4 weeks, but decreased granulomatous inflammation after 8 weeks, whereas chrysotile induced progressive interstitial granulomatous inflammation and fibrosis as a function of time.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.122-123
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• 2003

Apple stem grooving virus (ASGV) belongs to Capillovirus and infects pome fruits. Transmission mode of ASGV is known by grafting and mechanical inoculation into susceptible hosts, not by any other natural vectors. But we have observed the spread of ASGV in the field without mechanical inoculation or grafting. Transmission seems to be occurred from tree-to-tree and tree-to-susceptible herbaceous plants along but not across ditches in the field. In order to ascertain this possibility, various fungi were isolated and cultured from ASGV-infected plants and 69 isolates were characterized. By means of RNA dot-blot hybridization and PCR analysis, 3 isolates were sorted out for further studies. The isolates were identified to Tataromyces sp. and belonged to Phenicillium by morphological characteristics and molecular markers. As an experimental host, 10 kidney beans (Phaseolus vulgaris) were screened and Kyunggi-5 was selected for virus amplification and symptom development. Kyunggj-5 infected by fungi which seemed to carry ASGV showed the typical disease symptoms and viral coat protein genes were detected from all tested plants. To confirm the Koch's rule, fungi cultured from inoculation origins of kidney bean were grown on PDA media and re-inoculated to hosts. The fungi isolated from inoculation origins induced the typical disease symptoms on hosts. However virus free fungi did not induce any symptom on the experimental hosts. This bioassay showed that these typical symptoms were caused by virus, not fungi.

• Journal of fish pathology
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• v.9 no.1
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• pp.33-40
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• 1996

A filamentous form of mollicute-like bacterium was detected during a routine health survey of wild adult kuruma shrimp Penaeus japonicus. The kuruma shrimp were native to Japan and were imported to Korea. The histology showed no pathological changes. Transmission electron microscopy revealed extensive infections of hepatopancreatic epithelial cell by a pleomorphic, filamentous intracellular bacterium. The filamentous bacterium was of about 60 nm in diameter and 300 nm to more than $1{\mu}m$ in length. Teh morphology of bacteria were filamentous and branched with terminal blebs, or knobs, on the branches. They lacked the cell wall, and were bounded by the plasma membrane. They contained typical prokaryotic ribosomes and fibrillar DNA-like strands. No additional internal structure has been observed. They are considered to be mollicutes, based upon the morphological appearance and upon the cellular location.

• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.223-230
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• 2023

This study attempted to concider the morphological change of red blood cells after whole body irradiation. Blood samples used red blood cells of white mice and mouse after irradiation. Transmission electron microscope observation results, Anisocytosis was observed in red blood cells 20 days after 5 Gy irradiation. Triangle and tetrapod were observed for small red blood cell types. Poikilocytosis, sickle-shaped Drepanocyte, and Acantocyte were observed in general-sized red blood cells. Schizocyte was observed in red blood cells 20 days after 7 Gy irradiation. Scanning electron microscope observation results, Dacryocyte was observed with microcytes. It was also confirmed that red blood cells were get tangled with each other. In addition, polygonal shapes and half-moon shapes were also observed. In conclusion, it is judged that the modified form of pathological study is more important than the numerical change in the study of red blood cells by radiation exposure. In conclusion, it was confirmed that modified morphological studies are more important than numerical changes in the study of red blood cells by radiation exposure.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.140.2-141
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• 2003

Among over-wintering small brown planthoppers, population of the rice stripe virus (RSV)-viruliferous insects was surveyed throughout the country in late April of 2003 by using DAS-ELISA. Averaged population of the RSV-viruliferous insects in this year was 2.1％, which was lower than that of last year of 3.7％. However, the insect population in Seoul, Incheon and Kyeonggi areas were relatively high showing 6.7％, 6.2％ and 2.6％, respectively. Based on the survey results, it was expected that overall occurrence of RSV on rice could be decreased in this year, except certain areas. Ovarial transmission rate of RSV by the insects on diseased rice samples collected from 10 areas ranged from 22.2％ to 77.8％. Among 35 graminous weed species collected from rice fields in Ganghwa and Kimpo in 2002 and 2003, common reed and formosens were found to be infected by RSV. The result indicates that those weeds are potential alternative natural hosts of the RSV Further studies on ecological and pathological impacts of the alternative natural host of RSV are being processed.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.425-430
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• 2014

Amyloidogenic proteins often exhibit fibrillar polymorphism through alternative assembly processes, which has been considered to have possible pathological implications. Here, firefly luciferase (LUC) is shown to induce amyloid polymorphism of ${\alpha}$-synuclein, the major constituent of Lewy bodies found in Parkinson's disease, by acting as a novel template. The drastically accelerated fibrillation kinetics of ${\alpha}$-synuclein with LUC required the nucleation center produced by the active enzyme of LUC. Fluorescent dye binding, transmission electron microscopy, and Fourier transformed infrared spectroscopy revealed the morphologically distinctive amyloid fibrils of ${\alpha}$-synuclein prepared in the absence or presence of LUC. As the altered morphological characteristics became inherent to the mature fibrils, those properties were inherited to next-generations via nucleation-dependent fibrillation process. The seed control, therefore, would be an effective means to modify amyloid fibrils with different biochemical characteristics. In addition, the LUC-directed amyloid fibrillar polymorphism also suggests that other cellular biomolecules including enzymes in general are able to diversify amyloid fibrils, which could be self-propagated with diversified biological activities, if any, inside cells.

• Applied Microscopy
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• v.36 no.2
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• pp.83-91
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• 2006

The number and structure of synapses are dynamically changed in response to diverse physiological and pathological conditions. Since strength of synaptic transmission is closely related to the synaptic density on a neuron, both synaptogenesis and synapse loss may play important roles in controlling neuronal activity. Thus it is essential to estimate the number of synapses using an accurate quantitative method for better understanding of the numerical alteration of synapses under terrain experimental conditions. We applied physical disector principle to estimating the number of synapses per neuron in the dentate gyrus of adult mice. First, we measured the numerical density of granule cells using the physical disector principle. Second, the density of medial perforant path to granule cell synapses was estimated using the bidirectional physical disector. Then, the volume ratio of molecular layer to granule cell layer was measured. With these numerial values, we successfully calculated the number of synapses per neuron. Individual granule cells have approximately 6500 synapses in the dentate gyrus of adult mice $(6,545{\pm}330)$, which are comparable to those of other researchers. Our results showed that the estimation of synapse numbers per neuron using the physical disector principle would provide accurate and precise information on the numerical alteration of synapses in diverse physiological and pathological conditions. Following analyses of synapse numbers using this method will contribute to the better understanding of structural synaptic plasticity in a variety of experimental animal models.