• Korean Journal of Animal Reproduction
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• v.13 no.3
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• pp.127-133
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• 1989

This study was undertaken to understand development stage of ovary and changes of hormones concentration from February to May in the Israeli carp, Cyprinus carpio. The results obtained in these experiments are as follows ; 1. Serum LH levels began to increase sharphy in March, coinciding with the onset of rapid ovarian development. 2. LH levels were well correlated with changes in gonadosomatic index. 3. Dramatic increase in gonadosomatic index occurred during the months of March. 4. Ripe stage(Stage Ⅴ) rapidly increase in March. 5. Early perinucleolus oocyte radpily develop into late perinucleolus oocytes in March. 6. The vitellogenic phase begins as these late perinucleolus oocytes become transformed into early maturing oocytes through the accumulation of yolk. 7. The cytoplasm completely fills with yolk as oocytes reach the late maturing stage. 8. Changes in the microscopic appearances of the ovaries were well correlated with changes in both gonadosomatic index and macroscopic appearance. 9. It is concluded from these observations that LH plays a major role in sexual maturation of the Israeli carp.

• Korean Journal of Childcare and Education
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• v.17 no.5
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• pp.105-128
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• 2021

Objective: This study aimed to explore the experience and meaning of pre-service early childhood teachers who practiced health promoting activities for themselves. Methods: Research participants were 115 pre-service early childhood teachers enrolled in the health education for children course at one college in G region. The reports of activity records of their eight-week long health promotion activities were collected as qualitative data followed by content analysis being implemented. Results: First, the experience of the health promoting activities the participants took part in was categorized into 'Early phase of experience: A mix of worries and anticipation, and success and failure', 'Mid phase of experience: Being motivated by physical changes and records', and 'Late phase of experience: Continuous execution through habituation.' Second, the meaning of health promotion activities the participants took part in was categorized into 'A great opportunity for introspection', 'A meaningful start of college life', and 'A valuable chance to consider desirable roles of a teacher for early childhood health education.' Conclusion/Implications: The results of this study suggest that pre-service early childhood teachers should pay close attention to their health management, and that contents that emphasize the importance of teachers' health should be included in health education.

• Proceedings of the Membrane Society of Korea Conference
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• 1995.04a
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• pp.1-4
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• 1995

The microstructure of polymer membranes produced via thermally induced phase separation (TIPS) of polymer solutions is a strong function of both the early-stage (by spinodal decomposition or nucleation & growth) and the late-stage phase separation (referred to in general as coarsening). In the case of early stage effects, the membrane morphology resulting from a nucleation & growth mechanism is either a poorly interconnecsed, stringy, beady structure which is mechanically fragile or a well interconnected structure with highly nonuniform pore sizes. In contrast, spinodal decomposition results in a well interconnected, mechanically strong membrane with highly uniform pore sizes. Here I describe recent quantitative studies of the coarsening effects on the microstructure of membranes produced via TIPS process. The dependence of microstructure on coarsening time, quench depth, solution viscosity, and polymer molecular weight was investigated in order to distinguish among three possible coarsening mechanisms, Ostwald ripening, coalescence, and hydrodynamic flow, which may be responsible for structural evolution after the early-stage phase Separation (spinodal decomposition or nucleation & growth).

• Molecular & Cellular Toxicology
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• v.4 no.2
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• pp.164-169
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• 2008

Methylmercury (MeHg) is known to have devastating effects on the mammalian nervous system. In order to characterize the mechanism of MeHg-induced neurotoxicity, we investigated the analysis of transcriptional profiles on human 8k cDNA microarray by treatment of $1.4{\mu}M$ MeHg at 3, 12, 24 and 48h in human neuroblastoma SH-SY5Y cell line. Some of the identified genes by MeHg treatment were significant at early time points (3h), while that of others was at late time points (48h). The early response genes that may represent those involved directly in the MeHg response included pantothenate kinase 3, a kinase (PRKA) anchor protein (yotiao) 9, neurotrophic tyrosine kinase, receptor, type 2 gene, associated with NMDA receptor activity regulation or perturbations of central nervous system homeostasis. Also, when SH-SY5Y cells were subjected to a longer exposure (48h), a relative increase was noted in a gene, glutamine-fructose-6-phosphate transaminase 1, reported that overexpression of this gene may lead to the increased resistance to MeHg. To confirm the alteration of these genes in cultured neurons, we then applied real time-RT PCR with SYBR green. Thus, this result suggests that a neurotoxic effect of the MeHg might be ascribed that MeHg alters neuronal receptor regulation or homeostasis of neuronal cells in the early phase. However, in the late phase, it protects cells from neurotoxic effects of MeHg.

• 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.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.2
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• pp.117-131
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• 2000

Objectives: To develop a new immunohistochemical marker system for supplementation of the Noyes histological classification of the endometrium in women of child bearing age with regular menstrual cycles, and to employ this system to evaluate pathologic factors involved in endometriosis, and thus to ascertain if it is useful in diagnosis. Materials and Methods: Endometrial biopsies were sampled from the posterior fundus of 41 (24 proliferative phases, 17 secretory phases) women with regular menstrual cycles (28-32 days), and each sample was immunohistochemically stained according to Noyes et al (1975) for determination of expression for estrogen receptor (ER), progesterone receptor (PR), integrin ${\alpha}_1$, ${\alpha}_4$, ${\beta}_3$, COX-1 and COX-2. Then, the PR, integrin ${\beta}_3$ and COX-2 which were clearly expressed in the luteal phase was with endometrial samples were obtained from 20 cases of normal patients (group 1) and 25 cases with endometriosis (group 2) after confirming the day of ovulation by sex steroid level measurements 7-8 days after ovulation Results: In the regular menstruation group the expression of ER showed a tendency to be increased in the proliferative phase and decreased in the secretory phase, and was the highest in the proliferative phase. However, PR in the stromal cells showed no change in the entire menstrual cycle while in the epithelial cells, PR reached a peak in the late proliferative phase and was almost absent in the secretory phase. Integrin (${\alpha}_1$, ${\alpha}_4$, and ${\beta}_3$ expression in the epithelial cells was absent in the proliferative phase but ${\alpha}_1$ was strongly expressed starting from the early secretory phase into the entire secretory phase. ${\alpha}_4$ was expressed strongly in the early and mid secretory phases and disappeared in the late proliferative phase, while ${\beta}_3$ appeared after the mid secretory phase and continued to be expressed until the late secretory phase. Expression in the stromal cells was weak overall and did not show any cyclic pattern. COX-1 expression was shown as a cyclic pattern in the stromal and epithelial cells and was particularly strongly expressed in the mid secretory phase of epithelial cells, and in the mid secretory and menstruation phase of stromal cells. In the endometrial epithelial cells there was strong expression during the entire cycle with stronger expression in the secretory phase compared to the prolferative phase. COX-2 was clearly expressed in the late proliferative, early and mid secretory phases in the stromal cells. No expression was observed in the proliferative phase of the epithelial cells, but which began to appear in the early secretory phase reaching a significant pattern from the mid secretory phase onwards. There was almost no expression in the stromal cells. In the cases with endometriosis showing normal endometrial maturation according to the Noyes classification, PR expression was increased while Integrin-${\beta}_3$의 expression was significantly decreased compared to the normal group. Also, COX-2 expression was slightly decreased in the stromal cells of patients with endometriosis while it was significantly increased in the stromal cells. Conclusion: Immunohistochemical markers can supplement the original Noyes classification of histological endometrial dating and therefore ascertain existing pathologic conditions. Particularly for patients with endometriosis with normally mature endometrial cells, changes in COX-2 and integrin expression patterns may assist in elucidating pathophysiologic mechanisms and therefore aid in the diagnosis of abnormal implantation conditions, and consequently determine a treatment modality.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.2
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• pp.153-160
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• 1998

The objective of this retrospective study was to evaluate whether the transvaginal ultrasonographic analysis of endometrial pattern and thickness could predict the stage of menstrual cycle. Endometrial pattern and thickness were observed in those patients receiving infertility work up from April, 1994 to July, 1998 at Seoul National University Hospital. The study group was 185 patients with normal regular menstrual cycles. Among them, 44 patients received endometrial biopsy, and the date of endometrium was compared with the observed endometrial pattern and thickness. The observed endometrial pattern was presence or absence of central cavity echogenicity, triple line sign, endometrial hypoechogenicity, ring sign, endometrial hyperechogenicity and posterior acoustic sonic enhancement. The results were as follows; Central cavity echogenicity was seen throughout menstrual cycle. Triple line sign was observed in 81.1% of patients during early secretory phase. However, in mid to late secretory phase, triple line sign was appeared in only 6.8%. The percentage of positive endometrial hypoechogenicity was highest in early secretory phase. In contrast to hypoechogenicity, positive endometrial hyperechogenicty was highest in mid to late secretory phase. Ring sign was observed in 73.5% of the patients during early secretory phase with peak incidence. Posterior acoustic enhancement was seen in 72.7% of the patients during late secretory phase. The sensitivity and specificity of being a secretory phase if the patients showed hyperechogenic endometrium, were 84.2%, 83.3% respectively. The sensitivity and specificity of being a secretory phase if the patients showed posterior acoustic enhancement were 93.8%, 58.3% respectively. Endometrial thickness was not correlated with endometrial dating. In conclusion, transvaginal ultrasonographical delineation of the endometrial pattern might be useful tool in predicting endometrial status during normal menstrual cycle. But, endometrial thickness could not predict the endometrial dating.

• Applied Microscopy
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• v.34 no.3
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• pp.159-170
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• 2004

Spermiogenesis in the Korean squirrel, Tamias sibiricus, was investigated by transmission electron microscopy. Spermiogenesis was divided into Golgi, cap, acrosome, maturation and spermiation phases based on the characteristics of acrosomal changes and nuclear shape. Beside, the Golgi, cap and acrosomal steps were subdivided into three phases of early, middle and late phase respectively, the maturation step was divided into two phases of early and late phase, and spermiation step has only one phase. Thus, the spermiognesis of T. sibiricus was divided into a total of twelve phases. In Golgi phase (steps 1-3), a well developed Golgi complex was located close to the vesicles, the acrosomal vesicle fixd to a recess of nuclear membrane at step 3. During cap phase (steps 4-6), the acrosomal vesicle spred over the nuclear surface to cover a third of the nucleus, and the acrosomal granule was not yet flattened. At acrosomal phase (steps 7-9), the nucleus and acrosome were elongated but nucleoplasm was not condensed. During maturation phase (steps 10-11), the nucleoplasm was more condensed, and the mitochondria completely arranged the center of axoneme. The spatulate-sperm head was completely formed at spermiation phase (step 12).

• BMB Reports
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• v.34 no.3
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• pp.278-283
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• 2001

Antioxidant and redox enzyme activities are known to be involved in the cellular responses to various stresses. Their variations were observed according to the growth cycle of the fission yeast Schizosaccharomyces pombe. Peroxidase activity appeared to be notably higher in the early exponential phase than in the mid-exponential and stationary phases. However, catalase activity showed a variation pattern resembling the growth curve. Glutathione S-transferase activity was higher in the early exponential and late stationary phases. Activities of the two redox enzymes, thioredoxin and thioltransferase (glutaredoxin), were high in the stationary phase. However, their activities appeared to increase from the early exponential to mid-exponential phase. Total glutathione content had a varying pattern similar to that of thioredoxin and thioltransferase. However, its content in the early exponential phase was high. These results propose that antioxidant and redox enzymes tested are also involved in the mechanism of cell growth.

• Plant Resources
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• v.5 no.2
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• pp.155-160
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• 2002

The heading date is known to be controlled by two kinds of genetic constituent, photosensitivity and basic vegetable phase. For the latter, the effect of temperature in early growth period is critical to determine the shortness of vegetative growth periods in plant's life. A phytotron experiment on 55 rice cultivars, consisting of two ecotypes of rices, indica and japonica, was conducted at high and low temperature treatments at early growth stage to investigate the possible role of plant growth stimulus by high temperature to associate with shortening of heading date. The high temperature during the early growth stage stimulated the rice growth as measured by plant height with much difference of the growth response between indica and japonica. The conclusive finding that these growth stimulus in early growth stage was highly correlated with the acceleration of heading is, more or less, correlated with the heading of the late growth stage although we could not conclude the genes for early plant growth stimulus by high temperature is the same genes as the genes for accelerating of heading in the late growth stage of plants.