• Applied Microscopy
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• v.15 no.1
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• pp.1-12
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• 1985

In this study, the pathway and date of migrating Primordial germ cells (PGCs) were observed light microscopically and ultrastructural changes of them during migration were observed by electron microscopic examination. For these purpose, alkaline phosphatase reactions were used for identifying the PGCs and acid phosphatase reactions were used for observing their degenerating activities. Also, effects of actinomycin D on the migration of PGCs were examined. According to these results, at the 9th gestation day, PGCs were observed in the endodermal cells of yolk sac, at the 11th gestation day, they were seen in the hindgut and then entered into the dorsal mesentery by the 13th gestation day. At the 14th gestation day, they were located in the genital ridges. When PGCs were located in the hindgut and genital ridges, the positive reactions of alkaline phosphatase were dominated, but acid phosphatase reactions were limited in all stage except they were in dorsal mesentery. However, these reactions were lessened in case of actinomycin D treatment. By electron microscopic examination, PGCs had pseudopodia, tail process, trailing cytoplasm and nuage as the ultrastructural characteristics. In addition, these morphological features were damaged by actinomycin D treatment.

• The Korean Journal of Malacology
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• v.18 no.1
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• pp.15-21
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• 2002

The kidney of bivalve mollusks often contains remarkably high concentrations of both essential and non-essential metals and perform regulating and detoxicating activities. The kidney has also been proposed as a biological indicator for radioactive as well as for stable metals in the sea. The present study of the Antarctic clam, Laternula elliptica, concerns the functional morphology of the kidney epithelium, which contains highly accumulated heavy metals. The immunohistochemical and ultrastructural study was undertaken in order to find out the localization of metallothionein and heavy metals accumulated in the kidney of Laternula elliptica. In the immunohistochemical investigation, an intense metallothionein immunostaining reaction was found in the epithelial cells of the kidney of Laternula elliptica. Transmission electron microscopy showed that the epithelial cells contained numerous electron-dense inclusion bodies which were considered to be accumulated heavy metals.

• Korean Journal of Veterinary Research
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• v.24 no.1
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• pp.64-68
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• 1984

Undifferentiated leiomyosarcomas were encountered in two dogs, and an ultrastructural study was carried out. The results of this study were summarized as follows; 1. The nuclei of mosts tumor cells showed bilobate appearance. 2. Most cells of the tumors had not a distinct basement membrane. 3. Most cells of the tumors had a degenerative rough endoplasmic reticulum. 4. Intercellular matrix contained some amounts of collagen. 5. Attachment areas between tumor cells were not apparent, but a few tight junction were clearly seen. 6. Myofibrils were present in bipolor end area.

• The Korean Journal of Malacology
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• v.13 no.2
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• pp.175-184
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• 1997

A histochemical and ultrastructural study on the stomach epithelium of a land snail Nesiohelix samarangae was carried out during the period of June 1996 to May 1997. The stomach epithelium is simple columnar dpithelium and is consisted of three types of columnar cells, Type 1 cell which is majority in number has a brush border with microvilli on the free surface of the cell and contains numerous secretory granules supposed to be neutral mucopolysaccharide. Type 2 cell, elongated conical in shape. is rarely found in the dpithelium. This cell also has a brush border with microvilli on its free surface and contains well developed rough surfaced endoplasmic reticulum, Golgi bodies, and secretory granules in various electron densities. This cell seems to produce both of acid and neutral mucopolysaccharides. Type 3 cell, which is morphologically similar to the Type 1 cell, has microvili and cilia on the free surface and exists in group only in the limited regions of the stomach.

• Applied Microscopy
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• v.24 no.4
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• pp.32-40
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• 1994

This study was undertaken to study the morphological changes of rat synapses during early postnatal periods. Neonatal rats were grouped by 1st, 2nd, 3rd, 4th and 6th postnatal weeks, and we observed the ultrastructural pattern of the synapses in the external plexiform layer of olfactory bulbs by electron microscopy. The results were as follows; 1. The numbers of synapses, lengths of synaptic thickenings and amounts of synaptic vesicles were markedly increased in the external plexiform layer during four postnatal weeks. 2. There was a tendency of increasing the proportion of the asymmetric synapse and the curved synapses during maturation. From the above results, it is suggested that the size of synapse is increasing during maturation, and at the same time the asymmetric synapses are formed from the symmetric type and the curved synapses are from the plane type.

• 한국전자현미경학회:학술대회논문집
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• 2002.11a
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• pp.21-21
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• 2002

• The Journal of the Korean dental association
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• v.21 no.7 s.170
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• pp.555-564
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• 1983

• Journal of Periodontal and Implant Science
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• v.6 no.1
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• pp.20.2-20.2
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• 1976

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1998.06a
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• pp.167.1-168
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• 1998

• Applied Microscopy
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• v.20 no.2
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• pp.127-159
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• 1990

This study was investigated to elucidate the effect of chlorambucil on the heart in aging rats. Male rat ranging in age from 3 to 36 months were used. Each age groups(3, 6, 12, 18, 24, 36 months) included control and chlorambucil treated rats. As a part of the study, the ultrastructural changes in the left ventricular myocardial cells were described by using the qualitative and morphometric techniques. The results are summarized as follows. Age associated ultrastructural changes included: an increase in vacuoles, protrusion of plasma membranes, lipid droplets, and lipofuscins in myocardium of control groups. These changes which begin to occur at 12 months and continue through 36 months. At the 36 months some instance of unusual formation of contraction band and separation of intercalated discs were encountered. Morever, these changes and contents with chlorambucil treatment were remarkably increased in comparison with control groups. Age-dependent changes of control group measured with morphometry were not observed in the volume densities of mitochondria and myofibrils. But there was increase in interstitium. On the other hand decrease in sarcoplasmic reticulum and T-tubule system. In chlorambucil treated groups, volume densities of mitochondria and interstitium were increased in comparison with those of the control groups. But sarcoplasmic reticulum and T-tubule system were remarkably decreased.