• Applied Microscopy
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• v.20 no.1
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• pp.90-104
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• 1990

This study was carried out to investigate the ultrastructural changes of the proximal epiphyseal plate of the femur in young chickens that had been treated with monosodium glutamate(MSG). Eighty 1-day old broiler chickens(Hubbard strain) were divided into control and experimental groups. The experimental group received daily administration of MSG(3mg/g of body weight in 0.75% saline) per orally for 1, 3, 6, 9, 12, 15, 18 and 21 days, and were sacrificed with exanguination. The control group received an equal volume of 0.75% saline. For the transmission electron microscopy, the prehypertrophic cartilage zone of epiphyseal plate was cleaved, fixed with 2% glutaraldehyde(containing 0.2% ruthenium red), postfixed with 1 % osmium tetroxide, embedded in Epon 812, and stained with uranyl acetate and lead citrate. For the scanning electron microscopy, the calcified zone of epiphyseal plate was cleaved and coated with gold palladium. The results obtained were as follows; 1. On transmission electron microscopic examination, the sacculation decreased from 12 day to 21 day MSG administrated groups, and the vesiculation decreased in 18 and 21 day MSG administrated groups in rough endoplasmic reticulum of chondrocytes in prehypertrophic cartilage zone. The ruthenium red binding particles in pericellular rim, territorial matrix and interterritorial matrix increased from 9 day to 21 day MSG administrated groups, but the crystalloid materials decreased. 2. On scanning electron microscopic examination, the trabecular formation and calcospherites of calcification zone decreased in 18 and 21 day MSG administrated groups. The resorption cavities widened from 15 day to 21 day MSG administrated groups.

• Applied Microscopy
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• v.33 no.3
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• pp.243-250
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• 2003

Ultrastructural changes of the male germ cells and structure of spermatozoa in Paralichthys olivaceus were examined by means of the light and transmission electron microscopes. The spermatogonium has a large nucleus with a single nucleus with a single nucleolus in the interphase. Primary spermatocytes are identified by the formation of the synaptonemal complex in the karyoplasm. The secondary spermatocytes are more concentrated and contains numerous cell organelle in the cytoplasm. The nucleus of spermatid in spermiogenesis is more condensed in the karyoplasm, and show spherical structure in shape. Mitochondria of the spermatids are observed in the lower portion of the nucleus. The spermatozoon consists of the head, mid piece and tail. The acrosome is not observed in the head. Axial filaments of the flagellum consists of nine pairs of the peripheral microtubules and one pair of the central microtubules.

• Korean Journal of Plant Tissue Culture
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• v.25 no.6
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• pp.495-500
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• 1998

Ultrastructural changes of the isolated and cultured protoplasts from ginseng (Panax ginseng C. A. Meyer) callus were studies with electron microscopy. In the 3-day-cultured protoplasts, the cell organelles such as rough endoplasmic reticulum, ribosome, Golgi complex, mitochondria, proplastid increased in number and observed microtubules. Many vesicles derived from the Golgi complex were evenly distributed in the cytoplasm. Some of such vesicles protruded the outer surface of the plasmalemma, and formed the protuberances. Vacuole derived from endoplasmic reticulum included Golgi vesicles by the invagination of vacuoles. These vacuoles migrated toward the plasmalemma by a fusion process (exocytosis), after fusing the plasmalemma the cell wall materials released from the outer surface of the plasmalemma, and lastly deposited on the plasmalemma. Proplastids containing many starch grains, and microtubules parallel to the plasmalemma were observed near the plasmalemma. Connected fibrils which were observed on the outer surface of the 3-day-cultured protoplast were interpreted as the component of cellulose.

• Applied Microscopy
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• v.27 no.2
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• pp.131-144
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• 1997

The present study was carried out to investigate the processes of the ultrastructural differentiation and the acetylcholinesterase (AChE) activities of the developing rat retina. The results are as follows. The retina of fetal rat on the 13th day of gestation showed the early stage of differentiation. Briefly, there appeared dividing chromosomes, the plentiful free ribosomes, and the high ratio of nucleus to cytoplasm. The reaction products by AChE were localized at the membrane of endoplasmic reticulum and on the outer membrane of nucleus. Ultrastructures and AChE activities in the retina of the fetal rats on the 18th day of gestation were similar to those of the prior stages, except the appearence of rough endoplasmic reticulum and Golgi apparatus. According to the ultrastructural observations, the rat retina was still in immature state at birth, but the pigment epithelial cells were fully differentiated, e. g. the increase of melanin granules, the development of mitochondria and Golgi apparatus. The AChE activity was weekly detected. The differentiated retinal layers and the outer segment of photoreceptor cells were observed on the 7th postnatal day. And the pigment epithelium appeared to be fully differentiated. On the 14th postnatal day, rat retina were completely differentiated. In other words, the rat retina was characterized by the prominent outer segments, phagocytosed residues in the pigment epithelium, and the localization of reaction products by AChE in the synapses. In conclusion, the differentiation of rat retina is charaterized by the changes of cell shape, the increase of retinal layers, and the alterations of AChE activities. It seems that rat retina is to be functional from 2 weeks of birth onward, coinciding with the eye opening of the juvenile rats.

• Applied Microscopy
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• v.29 no.3
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• pp.315-321
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• 1999

Vitamin D is one of important factors involved in the regulation of bone metabolism. In osteoporosis, the therapeutic effect of vitamin D on the healing process of fracture has still been controversial. These studies were designed to understand the healing process of normal fibular fracture and the therapeutic effects of $1\alpha$, 25 dihydroxycholecalciferol on the osteoporotic fracture in rats. The simple transverse fractures of rat fibulae were produced with a rotating diamond saw. The histological and ultrastructural changes of rats were observed. The histological and ultrastructural studies revealed the healing of the fibular fracture in the 5th week after simple transverse fracture. The osteoporosis impaired more the healing of osteoporotic fibular fracture than normal non-osteoporotic fibular fracture. The healing process of osteoporotic fracture was facilitated by the treatment with $1\alpha$, 25 dihydroxycholecalciferol, however, was delayed more than the healing process of normal fracture. These results suggest that $1\alpha$, 25 dihydroxycholecalciferol was effective for reducing the deleterious effects of osteoporosis in fracture healing.

• Applied Microscopy
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• v.26 no.4
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• pp.431-446
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• 1996

This experiment was performed to study the ultrastructural changes of the juxtaglomerular cell of mice following subcutaneous injection of heavy metallic agents. Male mice were divided into normal and experimental groups. The mice were subcutaneouly injected with $HgCl_2$ (2mg, 5mg or 10 mg/Kg/BW) or with $K_{2}Cr_{2}O_7$(5 mg, 10 mg or 20 mg/Kg/BW). Mice were sacrificed on 6 hours, 3 days and 14 days after the injection. Kidneys were fixed in the 2.5% glutaraldehyde-1.5% paraformaldehyde solution, followed by refixation in the 1% osmium tetroxide solution. Dehydrated blocks were embedded in araldite mixture. The sections were cut on a LKB-V ultratome, and ultrathin sections stained with uranyl acetate and lead citrate were observed with JEM 100CX II electron microscope. The results were as follow: 1. Juxtaglomerular cell of the experimental groups showed some alterations, especially in the structures of protein synthesis including dilations and degradations of granular endoplasmic reticula, atrophy of Golgi complex, and numerous free ribosomes in the cytoplasm. 2. Juxtaglomerular cells treated groups showed a number of vacuoles, protogranules and some myelin figures in the cytoplasm, especially in the earlier groups. 3. Juxtaglomerular cells of treated groups, contained a large number of secretory granules showing variable electron densities and pleomorphism in later groups (2 weeks). From the above results, it was concluded that, the mercuric chloride or potassium bichromate induces acute renin release from juxtaglomerular cells of the mice, but many juxtaglomerular cells may secrete prematured secretory granules, or the synthetic system of the cell can not perform normal function.

• The Korean Journal of Zoology
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• v.33 no.1
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• pp.78-93
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• 1990

The ultrastructure of epididymal epithelium of 10, 20, 35 and 80 day-old mouse was observed to study the differentiation and function of the epithelial cells in connection with the absorption and secretion during sexual matruation. The differentiation of epididymis was divided into three phases of, 1) undiflerentiated phase until the day 20 after birth, 2) growing and differentiating phase between the day 20 and 35, and 3) maturating phase up to the adult. Each phase was closely related with the lumination of seminiferous tubule and the influx of spermatozoa within testicular fluid from testis. In adult, the ultrastructural features appeared an absorptive function in the principal cells of proximal caput epididymis, and a strong activity of protein synthesis and secretion in distal caput, corpus and cauda epididymis. Clear cells were predominantly located in corpus and cauda epidiymis, and plenty of absorption vesicles including membranous particles assumed to be the cellular residues from spermatozoa were observed at apical region. Therefore, the distribution of various cell types of epithelium and the ultrastructure even in the same type of epithelial cell, were different according to the epididymal regions.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.3
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• pp.345-353
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• 1999

In the studies on the hatching mechanisms in mammals, many investigators focused on the embryonic intrinsic factor(s) in in vitro culture, but the uterine environment as the extrinsic factor(s) is thought to play an important role in hatching mechanism. Therefore, to evaluate the effect of uterine environment on the hatching event in vivo, the immature(GV) and ovulated(MII) oocytes, and the late 2-cell embryos of mouse were transferred to pseudopregnant foster mother's uterus during peri-implantation period. So it was verified whether there would happen hatching by only uterine environment independently on embryonic stage. The ultrastructural changes of the zona surface of transferred group were compared with those 01 in vivo and vitro group by SEM. 36 hrs after transfer, the immature and ovulated oocytes almost degenerated, and the late 2-cell embryos developed to various embryonic stages. However, the embryos which didn't develop to blastula stage did not hatch. The ultrastructural network of ZP in transferred group seemed to be smoothed uniformly, which was different from in vitro group. In conclusion, it is suggested that the uterine environment during peri-implantation period enhances the embryo hatching by provoking the structural change of ZP.

• Anatomy and Cell Biology
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• v.55 no.1
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• pp.92-99
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• 2022

The liver is the largest gland of the gastrointestinal tract having both exocrine and endocrine functions. Developmentally it arises as a ventral outgrowth from the gut endoderm during 3rd week of intrauterine life. The foetal liver is very important because of its synthetic and hemopoietic potential. The present work aimed to see the detailed histogenesis and development of the foetal liver by cytological, immunohistochemical and ultrastructural study. The liver tissue of nine aborted foetuses of various gestational age were studied. For cytology: special stains like Masson trichrome, periodic acid Schiff and reticulin were used, immunohistochemical staining was performed with triple antibodies (c-myc, Ki-67 and Ber-H2), and for ultrastructure: aluminium mounted specimens were coated with gold and argon gas and observed under scanning electron microscopy (EM). Cytology and immunohistochemistry showed the development of duct patterns and hemopoietic patterns in all stages of fetogenesis. The ductal plate was marked by the layer of dark brown staining cells at the edge of two portal tracts. The haemopoietic cells with sinusoids and aggregation of hepatocytes were observed in the early weeks of gestation. EM showed tree-like branching of a portal canal depicting hepatic segmentation of foetal liver. The organizational changes in lobular pattern, duct pattern, and microstructure of liver during fetogenesis are very crucial to achieve the adult morphology in feature. Histogenesis of the foetal liver follows a multistep process depending upon the gestational age, any deviation from normalcy may lead to structural and functional abnormality later in life.

• Applied Microscopy
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• v.28 no.2
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• pp.215-224
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• 1998

To investigate ultrastructural changes on the adrenal glands of the developmental rats, tissues were collected at 20 days of gestation, at birth, 7 days, 15 days and 30 days after birth and studied by electron microscope. In the medulla of adrenal gland of the rat, two types of granules were observed at ultrastructural level. The one were adrenaline $(123\sim200nm)$ and the others were noradrenaline ($177\sim279nm$ of long axis, $124\sim194$ of short axis). Adrenaline granules were characterized by presence of round or spherical with low or moderate electron density. The granules showed a wide lucent or clean halo between the contents and the limiting membrane. On the other hand noradrenaline granules were characterized by the presence of irregular shape with high electron density. This granules showed a wide lucent between the contents and limiting membrane. These two types of granules were co-existed in one cell in the late gestation and at birth, but after that two types of cells were clearly observed. The different sizes and numbers of granules were observed with ages.