• Restorative Dentistry and Endodontics
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• 제13권2호
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• pp.283-294
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• 1988

The purpose of this study was to investigate the characteristic features of the cells and tissues of the chronic periapical lesions using light microscope and electron microscope. Fifteen dental periapical lesions were obtained from the patients undergoing periapical surgery. Each specimen was divided into two parts along the tooth axis. One part was routinely processed for histopathologic examinations. 12 periapical lesions were diagnosed as granuloma and 3 periapical specimens as periapical cyst. The other part was fixed in 2.5% glutaraldehyde in 0.1M sodium cacodylate buffer at pH 7.4 and 1% osmic acid in same buffer. They were embedded in Epon 812. The semithin sections were used for the orientation of the lesions and the ultrathin sections were stained conventionally and examined with AEI Corynth 500 electron microscope. The results were as follows. 1. PMN and macrophages, which were dominant cell type, were scattered in small or large numbers throughout the central destructive area of granuloma. In the granulomatous area, plasma cells and lymphoytes were found in significant number and a lot of new capillary formation were revealed. Clefts caused by cholesterol were often seen in the connective tissue. Occasionally foam cells became collected in groups and epithelial proliferation were present. 2. In both granuloma and cyst, some plasma cells contained narrow cisternae of granular endoplasmic reticulum of which was tightly packed with electron dense materials, and other cells exhibited dilated profiles of granular endoplasmic reticulum. 3. In the area where plasma cells and lymphocytes were collected in groups, lymphocytes with well developed nucleolus and profuse cytoplasm were found and differentiating plasma cells were also present. 4. In the epithelial strands of the granulomatous area, epithelial cells contained enlarged endoplasmic reticulum, tonofilaments and ribosoms. Toward the intercellular space epithelial cells protruded a few microvilli. In the intercellular space, exudate-like electron dense materials, most of which was attached to the plasma membrane, appeared. 5. Some foam cells filled with numerous lipid droplets and others had lipid droplets and crystal-like structures. 6. Cyst epithelium consisted of bright cells and dark cells. The former had bright cytoplasm and small amounts of ribosoms, and the latter dark cytoplasm, many ribosoms, mitochondria and elongated microvilli. 7. Epithelial cells near the cyst lumen protruded a lot of long microvilli toward intercellular space and cyst lumen.

• The Korean Journal of Zoology
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• 제15권3호
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• pp.111-131
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• 1972

Fine structures of retina of an ommatidium in dragonfly, having eyes of closed rhabdom type, were studied under light and electron microscopes. The ommatidia consisted of eight retinular cells distributed in a circular pattern and the retinular layer in turn can be divided into three sublayers according to the number of cells in the retina. Each retinular cell has different starting points in the retina and the length of retinular cells is varied greatly; the length of one distal retinular cell shows one half of that of others. In the middle layer, three proximal retinular cells interconnect the adjacent two rhabdoms which are triangular in the appearence of the cross section which in turn consisted of tubular, parallel and lamellated microvilli. The rhabdom is formed by three rhabdomeres, each of which is separated by $120^{\circ}$ between them, but they can be distinguished into two parts according to electron density. Around the outer part of microvilli composing rhabdom, electron density was much less than the inner part of the structure. The microvilli of the inner part appear to be connected to the cytoplasm of retinular cells. Rough endoplsmic reticulum with enlarged cisternae runs through the vacuoles in the outer part of distal retinular cells. Abundant mitochondria concentrated in the vicinity of rhabdom are found at the central part of the retinular cells, while in the area of immediate vicinity of the rhabdom, prominent vacuoles are observed. Above the rhabdom of an ommtidium stands a crystalline cone which is consisted of four cone cells arranged radially along the axis. The crystalline cone is surrounded by cells containing pigment granules. The outermost photoreceptor element of an ommatidium is corneal lens.

• Asian-Australasian Journal of Animal Sciences
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• 제14권1호
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• pp.101-103
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• 2001

Scanning Electron Microscopy of twelve lactating buffalo mammary gland was done. The lactating mammary gland showed alveolus, arrangement of blood vessels and myoepithelial cells on the alveolus, the formation of lobules and interlobular connective tissue. From the exposed alveolar lumen fat globule formation can be seen which is still attached to the alveolar surface by microvilli. This technique should further be extended to study the alveolar structure in detail during different stages of mammary gland development in buffaloes.

• Applied Microscopy
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• 제16권2호
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• pp.61-74
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• 1986

The anatomy of the renal papilla and pelvis of the bat(Pipistrellus abramus abramus Temminck) and their ultrastructure of the epithelium has been studied by means of light, scanning and transmission electron microscopy. The bats were captured at Ondal cave located in Yangchun-Myun, Tanyang-Kun, Chungchongpuk-Do, Korea in the active(July) and hibernating(January) phases. A conical renal papilla with several papillary foramina at the apex was curved toward the ureter. At the margin of the funnel-shaped renal pelvis, the fornix extended deeply into the kidney parenchyme was formed between the outer zone of the medulla and the cortex. The epithelium of the papilla covered the inner zone of the medulla. The epithelium of the fornix medially overlayed the outer zone of the medulla, and laterally the cortex. The surface epithelium of the papilla was simple columnar in shape with the scanty organelles and the short microvilli on their luminal surface. The fornix was Jined with $1{\sim}2$ cell layered squamous epithelium. On the medial surface of the fornix, two types of the superficial epithelial cells were identified; one had numerous short microvilli and the other had the microplicae and plaques on their luminal surface. The lateral surface of the fornix lined with the epithelial cells showed microridges and plaques on the luminal surface. The epithelial cells on the medial and lateral surfaces of the fornix were similar to their internal ultrastructures. The pelvic epithelium was a typical transitional type, which was composed of a layer of basal cells, one or two layers of intermediate cells, and a layer of superficial(facet) cells. The fusiform vesicles were observed in the cytoplasm of the intermediate and facet cells. There were no noticeable morphological changes in the epithelium of the papilla, fornix and pelvis except the medial epithelium of the fornix in the hibernating cycle. The microvillar cells were more numerous in the hibernating phase than in the active phase. The morphology, of the renal papilla and fornix of bats, indicates that a functional relationship may exist between the pelvic urine and the renal parenchyme.

• Development and Reproduction
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• 제2권2호
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• pp.157-163
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• 1998

Preimplantation embryos of the rat was examined by the morphological changes in the cortical granule envelope (CGE), blastomere surface, and zona pellucida (ZP) of embryo after cortical reaction. The ultrastructural characteristics and CGE of embryos were observed with the scanning electron microscope and fluorescence microscope. In the ultrastructural characteristic of embryo surface, surface microvilli were shortened and the CGE-like structure existed above microvilli in eight-cell embryo. Rough spongy surface and decreased network numbers were key characters of embryonic ZP compared to unfertilized oocyte. The CGE formed by cortical reaction existed in perivitelline space during embryo development but it was thin and locally distributed ill contrast to fertilized oocyte. The present results indicate that cortical reaction forms cortical granule envelope in perivitelline space and causes not only zona hardening, but also ultrastructural changes in ZP and cell membrane of preimplantation embryos.

• Development and Reproduction
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• 제4권1호
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• pp.1-6
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• 2000

Ultrastructure of the zona radiata the micropyle and fertilization process in the rainbow trout (Oncorhynchus mykiss) were examined by light, scanning and transmission microscopes . The egg micropyle of rainbow trout consists of a funnel-shaped vestibule and a tapered canal transversing the zona radiata. The micropyle showed the type with a flat pit leading into a long canal and the micropylar wall showed the clockwise spiral structure. There were a great number of microvilli secreting adhesive materials having trapping function attracting the spermatozoa in the vicinity of micropyle. It was apparent that ridges extended between the projections. In the initial stages of penetration, the spermatozoon still within the micropylar canal attached perpendicularly at its apical tip to the egg surface, then the sperm head was rapidly engulfed by the folded egg surface with its many microvilli. The spermatozoon disappeared from the outer surface of the egg before the fertilization cone completely retracted 250 seconds after insemination. No interconnecting ridges was present in the egg surface. In short, the block to polyspermy to permit entry of a single sperm is considered to be mechanical by the morphological design of the micropyle and fertilization cone.

• Applied Microscopy
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• 제23권1호
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• pp.109-124
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• 1993

The prenatal development of thoracic spinal cord was studied by electron microscope in human embryos and fetuses ranging from 9mm to 260mm crown-rump length (5-30 weeks of gestational age). Ependymal cells in all fetal ages had conspicuous junctional complexes close to the lumen of the central canal into which microvilli and cilia projected. The ependymal cells contained numerous longitudinally arranged mitochondria, flattened cisternae of endoplasmic reticulum and Golgi complex. At 20 mm embryo, the floor and roof plates were composed of ependymoglial cells and undifferentiated neuroepithelial cells. The neuroepithelia of the sacral spinal cord were delineated from central medullary cord. By 100 mm fetus few undifferentiated neuroepithelial cells remained in the floor and roof plates. At 150 mm fetus, the whole central canal was formed by ciliated columnar epithelial cells containing cilia with basal bodies. The microvilli became tangled and club-shaped and formed a matted surface. The canal was filled with areas of dark and pale amorphous materials bounded by membrane-like structure. These two types of material were found throughout the whole central canal from 100 mm fetus onwards. By 260 mm fetus, microfibrils were first observed in the ependymal cells. In conclusion, it seems that early development and differentiation of central canal ependyma are simlar to that in other part of the brain ventricular system although ependymoglial cells are more prominent.

• Applied Microscopy
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• 제30권1호
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• pp.61-72
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• 2000

Three fertilization envelopes (FE) have been observed after the artificial insemination of U. unicinctus oocytes. The substances of the first fertilization envelope, which is an effective barrier against excessive sperm, come mainly from the surface coat of the oocyte. The secretions of the cortical granules take part in formation of the 2nd fertilization envelope. Histologically, the 3rd fertilization envelope is not amorphous as seen under light microscope, but contains numerous panicles under electron microscope, which would be contributed to harden the envelope by 60 min after the fertilization. With the substantial similarity between the 1st fertilization envelope and the surface coat of the oocyte, and the coincidence of retraction of microvilli and the formation of the 1st fertilization envelope, it is suggested that the microvilli contain the sperm receptors in U. unicinctus. Some granular substances from the distal part of the acrosome diffuse on the surface coat of the oocyte while the acrosomal tubules penetrate into the surface coat. The acrosomal tubules arise from the proximal part of the acrosome and pass through the acrosomal lumen.

• Fisheries and Aquatic Sciences
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• 제7권3호
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• pp.115-121
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• 2004

Experiments were carried out to investigate Cd accumulation, elimination and cell response in juvenile rockfish (Sebastes schlegeli) exposed to sub-chronic dietary Cd (0, 0.5, 5, 25 and 125 mg/kg) for 60 days and depuration periods of 30 days. Cd accumulation in the kidney of cock fish increased with exposure periods and concentrations for the 60 days of dietary Cd exposure. After the end of the dietary Cd exposure, Cd accumulation values in the kidney were $52.9{\pm}9.94\;{\mu}g/g$ and $90.6{\pm}15.7\;{\mu}g/g$ for those exposed to 25 mg/kg and 125 mg/kg Cd, respectively. The accumulation factors increased with the exposure period in the kidney. Cd elimination in the kidney of rockfish did not vary significantly and remained constant after the cessation of the dietary Cd exposure. In the primary exposure periods, the effect of kidney tissue in the rockfish exposed to dietary Cd was observed the swelling of capillary of the glomerulus. In addition, there was also hydropic swelling within the pyknotic nuclei, some of hyaline droplet accumulation and the microvilli showed a positive reaction to alcian blue in the tubular cells. While exposure time and concentrations were increased, there was a lot of hyaline droplet accumulation and the microvilli showed a positive reaction to alcian blue in the tubular cells. Fused renal tubule and its necrosis were observed after 60 days at l25 mg/kg.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제36권3호
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• pp.270-275
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• 2003

Histochemical characteristic and ultrastructure of the mantle of the granular ark, Tegillarca granosa are described using light and electron microscopy. The mantle of the clam is composed of outer epidermis, connective tissue and inner epidermis. The simple epidermis consists of supporting cells, ciliated cells of the two types and secretory cells of three types. Connective tissue is composed of matrix, collagen fibers, muscular fibers and hemolymph sinus. The columnar supporting cell is covered with microvilli on the free surface. Ciliated cells are distributed in the inner epidermis with numerous cilia, microvilli and tubular mitochondria. Secretory cells could be classified into three types (A, B and C) with morphological features of the secretory granules. Type A secretory cells contains secretory granules with fibrous materials of high electron density Type B secretory cells are more abundant than the other cells, and contains secretory granules of membrane-bounded and high electron density. Secretory granules of the type C cells are divided into fibrous core layer and homogeneous peripheral layer. Type B secretory cells are abundant in the both epidermis of marginal mantle, while large number of type A and C secretory cells are evident in the outer epidermis of the central and umbonal mantle. This result showed that the outer and the inner epidermis of the mantle are related with shell formation and cleaning of the mantle cavity, respectively.