• Journal of Embryo Transfer
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• v.25 no.4
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• pp.215-219
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• 2010

The objective of this study was to examine the reproductive characteristics of cloned miniature piglets produced from surrogate domestic pigs. Somatic cell nuclear transfer (SCNT) miniature pig embryos were transferred into domestic pigs. As controls, domestic pigs of the same breed with surrogates for SCNT embryos and miniature pigs of the same breed with the somatic cell donor were bred by artificial insemination and natural mating, respectively. Surrogate domestic pigs that farrowed cloned miniature piglets had a significantly longer gestation length (118.1 days) than conventionally bred domestic (115.4 days) and miniature (115.5 days) pigs. Furthermore, the birth weight of cloned miniature piglets produced from domestic pigs (743 g) was significantly greater than that of miniature piglets produced by natural breeding (623 g). Also, cloned miniature piglets had a significantly lower weaning rate (49.7%) than conventionally produced domestic (91.5%) and miniature (100%) piglets. No differences were observed between female and male cloned piglets in gestation length, litter size, birth weight, or weaning rate. Our results demonstrate that gestation length is extended in domestic pigs that are transferred with SCNT miniature pig embryos and that cloned miniature piglets have increased birth weight and high pre-weaning mortality.

• Applied Microscopy
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• v.15 no.2
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• pp.19-30
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• 1985

Morphogenesis of rat spleen was studied by light and electron microscope from the fetal stage till the newborn or adult stages. The results indicate as follows: at the 14th day of gestation rat spleen, as an early form, consists of intercellular spaces and mesenchymal cells. And at this stage the spleen is in a premature state, then it appears its adult condition in structures after the 7th postnatal day. Erythropoiesis is shown to be an active process in rat spleen beginning about the 18th day of gestation, and once established the process continues at least till the 7th postnatal day. At the 20th day of gestation, there are splenic nodules, trabeculae, venous sinus, and granular leucocytes such as neutrophils and basophils in rat spleen. Lymphocytes appeared to be well differentiated at the 7th postnatal day and were present till the adult stage. While degenerating erythrocytes are phagocytosed by macrophages. In conclusion, rat spleen started to be appeared from the 14th day of gestation and erythropoiesis in rat spleen was carried out for about 10 days between prenatal and postnatal stage. Erythrophagocytosis was accomplished by macrophages and it is suggested that the proper functions of rat spleen set off from the 7 th postnatal day when its structures are similar to the adult's.

• Applied Microscopy
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• v.28 no.2
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• pp.207-213
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• 1998

To investigate ultrastructural changes on the adrenal cortex 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 transmission electron microscopy (TEM) the mitochondrial cristae of zona reticularis in the adrenal cortex of rats were a vesicular type and the vesicles were formed prior to 20 days of gestation. Also, the numbers of vesicles were $56.2{\pm}25.3$ in 20 days of gestation, $174.0{\pm}74.7$ at birth, $127.8{\pm}74.7$ in 7 days, $87.1{\pm}40.8$ in 15 days and $86.7{\pm}53.8$ in 30 days after birth, In this study, it was identified that the vesicles of mitochondrial cristae were formed by budding. The dense bodies were also observed in the nuclei of cortex cells from 20 days of gestation to 30 days after birth.

• Journal of Animal Science and Technology
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• v.52 no.1
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• pp.57-64
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• 2010

This study was conducted to compare the aspects of behavior between miniature pigs and conventional sows during gestation and lactation periods. Miniature pigs and conventional sows at 3 parity were used in this experiment with 4 pigs per treatment. The behavioral patterns and stereotyped behaviors were observed on day 60 and 90 of gestation, at farrowing, and on day 10 of lactation before and after the feeding. On 60 and 90 days of pregnancy, both treatments showed the tendency of frequent lateral lying rather than other postures. On ventral lying, eating and drinking, miniature pigs spent more time than conventional pigs at day 90 of gestation (P<0.01, P=0.0539, P<0.05, respectively). The occurrence of stereotyped behaviors included bar biting and bar mouth chewing. At 90 day of pregnancy was observed, conventional pigs was higher than miniature pigs (P<0.05). At farrowing, miniature pigs spent more time on ventral lying, standing and walking than conventional sows (P<0.05), however, there were more frequency of drinking and eating. And on day 10 of lactation, there was no significant difference in stereotyped behaviors between miniature pigs and conventional sows. In conclusion, miniature pigs were generally more sensitive than conventional sows although sows were reared in stall during gestation and lactation period and the behavioral pattern during lactating period showed the similarity between miniature pigs and conventional sows for protection of nursing pigs. In consideration of the general reproductive performance of conventional sows, the high sensitivity and stress of miniature pigs did not affect the reproductive performance of miniature pigs.

• Applied Microscopy
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• v.21 no.2
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• pp.96-116
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• 1991

The authors studied the morphological distinctions of each of the epidermal layers and the time of appearance of the keratohyalin granules and tonofilaments by the processing of development. The skins were obtained from fetal rats at the age of 14th, 16th, 17th, 18th, 19th and 20th day of gestation, of 1st and 3rd day of neonatal life and of 4th week after birth. The specimens were staind with uranyl acetate and lead citrate. The results obtained were as follows. 1. On the 16th-gestation day, the intermediate layer which contained numerous ${\alpha}-and\;{\beta}$-glycogen particles was appeared, and hemidesmosomes and desmosome were observed as well. 2. Tonofilaments were first observed on the 17th gestation day. 3. Above-mentioned intermediate layer was differentiated into the granular layer and the spinous layer on the 18th-gestation day. Keratohyaline granules were appeared in association with the ribosomes and the tonofilaments and the compound granules were lipoid granules which were surrounded by ribosomes at the periphery. 4. Ultimately, keratinization began to take place from the 20th-gestation day. At the age of 4th week, the thickeness of epidermis and the amount of keratohyaline granule and tonofibrils were decreased. It is consequently suggested that in the differentiation process of the rat epidermis, keratinization begins after formation of hemidesmosomes and desmosomes, from which the tonofilaments are formed and after keratohyaline granules are formed. Therefore appearance of the keratohyaline granules and formation of the tonofilament appears to have a close relations with the keratinization process of the rat epidermis.

• Korean Journal of Veterinary Research
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• v.32 no.2
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• pp.267-273
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• 1992

The purpose of present study was to investigate the progesterone concentrations throughout gestation and peripartum period, and the return to the first estrus postpartum for improvement of reproductive efficiency in Korean native goats. The average length of gestation was 148 days(range : 144~154 days) and the average number of live births was 2 kids(range : 1~5 kids) in 12 Korean native goats. Progesterone concentrations were measured in blood samples taken from 12 goats every 5 days during gestation period. Plasma progesterone concentrations were 0.10 ng/ml at Day 0 of pregnancy and increased gradually until Day 20(6.58 ng/ml). Then they decreased slightly from Day 30 to 40(range : 4.32~4.82 ng/ml), increased again after Day 40 and remained thereafter until Day 140(range : 4.32~10.36 ng/ml). The progesterone levels declined sharply to basal levels at parturitum. Plasma progesterone concentrations during the pestpartum were 6.98 ng/ml at 10 days, 4.86 ng/ml at 6 days 3.18 ng/ml at 2 days before parturition, and 0.10 ng/ml at parturition, respectively. The basal levels were maintained until the first estrus postpartum. The mean intervals from parturition to the first estrus postpartum on the basis of progesterone determination and estrus detection were $100{\pm}64(mean{\pm}S.D.)$ days in 7 Korean native goats.

• Journal of Animal Science and Technology
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• v.59 no.4
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• pp.7.1-7.13
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• 2017

Background: Selenium is one of the trace minerals whose deficiency is known to lead to complications of female reproduction. The identified gaps in researches regarding selenium and pregnancy include optimizing the dosage of selenium supplementation, timing of supplementation, finding the best form and type of selenium, and selenium administration combined with other antioxidants. Hence, this study was conceptualized to address one of the identified gaps, that is, to find out the best timing of selenium administration around the time of pregnancy. Specifically, this study aimed to assess the effects of maternal Selenium-supplementation, administered at various stages of periconception period, on murine blastocyst morphology, percent occurrence of good quality blastocysts, and implantation status. Methods: ICR female mice were randomly assigned into the unsupplemented group (Group I) receiving basal diet without selenium, and treatment groups given with $3.0{\mu}g$ selenium-supplement per day during pregestation only (Group II), pregestation-throughout-gestation (Group III) and gestation only (Group IV). Both blastocyst morphology and implantation status were assessed. Results: The morphometric measurements of blastocysts appeared to be unaffected by selenium-supplementation at different stages of periconception. Selenium-supplementation at pregestation only (Group II) and gestation only (Group IV) produced higher percent occurrence of good quality blastocysts and lower percent pre-implantation loss than Group III. Among all the treatment groups, Group III (Selenium-supplementation during pregestation-to-gestation) yielded the lowest quality blastocysts and highest percent pre-implantation loss. Conclusion: Maternal selenium-supplementation during pregestation and gestation stages of the periconception period yielded a high percent occurrence of good quality blastocysts and pre-implantation success.

• The Korean Journal of Zoology
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• v.37 no.4
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• pp.478-487
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• 1994

The developmental changes of three enteroendocrine cells, i.e. gastrln, somatostatin and serotonin, of gastric and small intestinal mucosa in pre- and postnatal rat were examined by peroxidase-antiperoxidase (PAP) method. In the course of development, gastrin cells were obsenred in the pyloric gland region and the whole part of small intestine, while somstostatin and serotonin cells in the whole gastric gland region and small intestine. More entroendocrine cells were detected in the pyloric gland region and duodenum than in the other portion. In the stomach, gastrin, somatostatin and serotonin ceils were first obsenred in the pyloric Bland region on 17, 19 and 19 days of gestation respectively. The small intestinal gastrin and serotonin cells were first appeared in the duodenum and iriunum on 17 and 15 days of gestation respectively, and somatostBtin cells in duodenum on 17 days of gestation. The number of cells examined from the stomach were increased from fetal to weanling period and showed a decrease during adult period: the notable increase was shown at the end of suckling period or at early weanling period. The cells of the small intestine increased from fetal to suckling period, especially, these cells markedly increased at the end of fetal period or at early suckling period, and decreased from weanling period. The shape of these cells was oval or fusiform during fetal period. In the stomach, most of gastrin cells turned out to be oval and open-type from suckling period, while the remaining two tripes of cells were oval and open- or closed-type. In the small intestine, 311%Ves of cells examined were changed to fusiform and open-type from the end of fetal period. Three types of cell were distributed over the stratified epithelium on 15 and 17 days of gestation. In the stomach, these cells were distributed lower gastric pit and gland from the following fetal period, and were detected mainly on the upper part of gland from suckling period, and then obsenred on the whole part of gland. In the small intestine, most of cells distributed over only between epithelium of villi on 19 days of gestation, increased in number on the crypt from following fetal period, and also observed abundantly in the crypt at adult period.

• Clinical and Experimental Pediatrics
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• v.57 no.4
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• pp.171-177
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• 2014

Purpose: Eosinophilia is common in premature infants, and its incidence increases with a shorter gestation period. We investigated the clinical significance of eosinophilia in premature infants born at <34 weeks gestation. Methods: We analyzed the medical records of premature infants born at <34 weeks gestation who were admitted to the neonatal intensive care unit at Ewha Womans University Mokdong Hospital between January 2003 and September 2010. Eosinophilia was defined as an eosinophil percentage of >3% of the total leukocytes. Perinatal parameters and clinical parameters were also analyzed. Results: Of the 261 infants born at <34 weeks gestation, 22.4% demonstrated eosinophilia at birth. The eosinophil percentage peaked in the fourth postnatal week at 7.5%. The incidence of severe eosinophilia increased after birth up to the fourth postnatal week when 8.8% of all patients had severe eosinophilia. Severity of eosinophilia was positively correlated with a lower gestational age, birth weight, and Apgar score. Respiratory distress syndrome, bronchopulmonary dysplasia, nephrocalcinosis, intraventricular hemorrhage, and sepsis were associated with a higher eosinophil percentage. The eosinophil percentage was significantly higher in infants with bronchopulmonary dysplasia from the first postnatal week and the percentage was the highest in the fourth postnatal week, with the maximal difference being 4.1% (P<0.001). Conclusion: Eosinophilia is common in premature infants and reaches peak incidence and severity in the fourth postnatal week. The eosinophil percentage was significantly higher in bronchopulmonary dysplasia patients from the first postnatal week. Severe eosinophilia was significantly associated with the incidence of bronchopulmonary dysplasia even after adjusting for other variables.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.483-499
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• 1995

Mandibular first molars of the rats were undertaken to observe the radiosensitivity of amelogenesis. Twenty four Sprague-Dawley rats received 396cGy radiation with the MK Cell irradiator using Cs-137, and twenty four rats served as control. They were devided into two groups; Group 1 which received radiation at the 14th day after gestation and group 2 which received radiation at the 19th day after gestation. Light Microscopy and Transmitted Electron Microscopy investigation was undertaken in the group 1 at the 15th, 18th, 20th, 22nd(2 days after birth), and 25th day(5 days after birth) after gestation, and in the group 2 at the 21th(birth day), 22nd(2 days after birth), and 25th(5 days after birth) day after gestation. The following histopathologic findings were obtained. 1. Compared with control group, experimental group showed a delayed formation of enamel and dentin due to slow rate of differentiation of undifferentiated mesenchymal cells. 2. In the experimental groups, the arrangement of the inner enamel epithelium was irregular and there were many vacuoles in the cytoplasm. There were dilated rER and mitochondria, increase of the intercellular space, and loss of the cellular polarity. 3. In the group 1, early enamel without Tomes' process, and early organic matrix was observed at the 25th day after gestation. 4. In the group 2, histopathologic changes were similar to those of the group 1, but the degree of changes was more severe than that of the group 1.