• International Journal of Oral Biology
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• v.40 no.3
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• pp.127-133
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• 2015

The salivary gland undergoes complex process of growth and differentiation of the branching morphogenesis of ductal system during the prenatal and early postnatal periods which are regulated by various elements in the extracellular matrix. Extracellular matrix metalloproteinase inducer (EMMPRIN) is a cell adhesion molecule. In the present study, localization and expression of EMMPRIN in development and effects of chorda-lingual denervation and cyclosporine A (CsA) treatment on the EMMPRIN expression were investigated. Immunohistochemistry, RT-PCR and Western blot were used to determine expression level. Immunohistochemistry revealed that EMMPRIN was localized specifically in the cytoplasm of ductal cells, not acini of the submandibular gland all the postnatal periods. At prenatal day 18, when the formation of ducts was not definite, no immunoreactivity was observed. Both Western blot and RT-PCR analyses revealed that EMMPRIN expression was maintained up to postnatal day 7, decreased after postnatal day 10. The EMMPRIN expression was upregulated by the surgical denervation of the chorda-lingual nerve in the gland as well as by the CsA treatment. The present study suggests that EMMPRIN is a crucial molecule for maintaining physiological functions of the salivary gland.

• Clinical and Experimental Pediatrics
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• v.62 no.10
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• pp.367-373
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• 2019

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of preterm infants with multiple factors affected from prenatal to postnatal periods. Despite significant advances in neonatal care over almost 50 years, BPD rates have not decreased; in fact, they may have even increased. Since more preterm infants, even at periviable gestational age, survive today, different stages of lung development affect the pathogenesis of BPD. Hence, the definition of BPD has changed from "old" to "new." In this review, we discuss the various definitions of BPD, risk factors from the prenatal to postnatal periods, management strategies by phase, and future directions for research.

• Clinical and Experimental Pediatrics
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• v.48 no.8
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• pp.806-812
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• 2005

Repair mechanisms in the postnatal and mature central nervous system(CNS) have long been thought to be very limited. However recent works have shown that the mature CSN contains neural progenitors, precursors, and stem cells that are capable of generating new neurons, astrocytes, and oligodendrocytes especially in germinative areas such as the subventricular zone of the lateral ventricles, the dentate gyrus of the hippocampus. These findings raise the possibilities for the development of novel neural repair strategies via mobilization and replacement for dying neurons of neural stem cells in situ. Indeed recent reports have provided evidences that endogenous stem cells are activated in response to various injuries, and in some injury models, limited neuronal replacement occurs in the CNS. Here, current understandings for endogenous neurogenesis and induction neurogeneis in postnatal CNS including neonatal brain are summarized and discussed.

• Clinical and Experimental Reproductive Medicine
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• v.39 no.4
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• pp.144-152
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• 2012

Objective: Concerns are growing about the decrease in male reproductive health. Caffeine is one of the popular nutrients that has been implicated as a risk factor for infertility. In the present study, we examined whether in utero and lactational exposure to caffeine affects the reproductive function of the offspring of rats. Methods: Pregnant rats received caffeine via drinking water during gestation (26 and 45 mg/kg) and lactation (25 and 35 mg/kg). Body and reproductive organ weight, seminiferous tubule diameter, germinal epithelium height, sperm parameters, fertility rate, number of implantations, and testosterone level of the offspring were assessed from birth to adulthood. Results: Significant dose-related decreases were observed in the body and reproductive organ weight, seminiferous tubule diameter, and germinal epithelium height of the offspring. Sperm density had declined significantly in offspring of the low-dose and high-dose groups, by 8.81% and 19.97%, respectively, by postnatal day 150. The number of viable fetuses had decreased significantly in females mated with male offspring of the high-dose group at postnatal days 60, 90, 120, and 150. There were also significant reductions in testosterone levels of high-dose group offspring from birth to postnatal day 150. Conclusion: It is concluded that maternal caffeine consumption impairs gonadal development and has long-term adverse effects on the reproductive efficiency of male offspring rats.

• International Journal of Oral Biology
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• v.43 no.4
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• pp.177-183
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• 2018

The objective of this study was to examine the expression pattern of Kelch-like ECH-associated protein 1 (Keap1) in the maxillary $2^{nd}$ molar germs of rats. We used the maxillary $2^{nd}$ molar germs in rats' pup at postnatal day 3 (bell stage), 6 (crown formation stage) and 9 (root formation stage). The investigation on mRNA and protein levels were done using reverse transcription - polymerase chain reaction and western blot. Localization of Keap 1 in the maxillary $2^{nd}$ molar germs were revealed through immunofluorescence staining. Keap1 from the maxillary 2nd molar germs were mostly manifested on postnatal day 3 and dramatically decreased on postnatal day 6 and 9 at mRNA and protein levels, while amelogenin and ameloblastin increased during the development of maxillary 2nd molar germs. During immunofluorescence analysis, the strong immunoreactivity against Keap1 was detected in the apical side of ameloblasts at the presecretory and secretory stages. However, Keap1 expression was hardly observed in the ameloblasts at the maturation stage. These results shows that Keap1 is strongly expressed in the presecretory and secretory ameloblasts of amelogenesis, and suggest that Keap1 may be a crucial molecule for the regulatory mechanisms tasked with the formation of enamel layer.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.2
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• pp.339-351
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• 1997

The purpose of this study was to investigate the distribution of nerves in the rat circumvallate papilla by each developing stage. The distribution of nerves in the rat circumvallate papilla were investigated by means of immunohistochemistry for detection of calcitonin gene-related peptide(CGRP). The results were as follows : CGRP-immunoreactive(IR) nerve fibers entered the base of the papilla laterally to form a subepithelial plexus. On the 1st postnatal day, the bead-like appearance, typical appearance of CGRP-IR nerve fiber, was seen, but from the 5th postnatal day the bead-like appearance was seen less clearly and nerve fibers looking like a line were often observed. Mature taste buds having taste pores were first seen at the 10th postnatal day and then, increased markedly after this stage. CGRP-IR nerve fibers entering the epithelium were rarely seen on the 5th postnatal day but they increased in number on the 10th postnatal day when mature taste buds having taste pores were firstly observed and then on the 15th postnatal day, they were observed abundantly throughout entire epithelium. But from the 20th postnatal day, the nerve fibers in the lower two-third of the trench wall in which taste buds exist decreased but on the top surface and upper one-third of the trench wall the nerve fibers were observed limitedly.

• Journal of Embryo Transfer
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• v.28 no.2
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• pp.149-155
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• 2013

Mullerian inhibiting substance (MIS) is a member of the TGF-${\beta}$ (transforming growth factor-${\beta}$) family whose members play key roles in development, suppression of tumour growth, and feedback control of the pituitary-gonadal hormone axis. MIS is expressed in a highly tissue-specific manner in which it is restricted to male Sertoli cells and female granulose cells. The serum levels of MIS in prenatal and postnatal ICR mice were measured using the enzyme-linked immuno-solvent assay (ELISA) using the MIS/AMH antibody. Mice were grouped by age: the significant periods were at the onset of development. During sex organ differentiation, no remarkable difference between female and male foetus MIS serum levels (both<0.1 ng/ml) was observed. However, MIS serum levels in pregnant mice markedly changed (4.5~12.2 ng/ml). After birth, postnatal female and male mice serum MIS levels changed considerably (male: <0.1~138.5 ng/ml, female: 5.3~103.4 ng/ml), and the changing phase were diametrically opposed (male: decreasing, female: fluctuating). These findings suggest that MIS may have strong associations with not only develop-ment but also puberty. For further studies, establishing the standard MIS serum levels is of importance. Our study provides the basic information for the study of MIS interactions with reproductive organ disability, cancer, and the effect of other hormone or menopause. We hypothesise that if MIS is regularly injected into middle-age women, meno-pause will be delayed. We detected that serum MIS concentration curves change with age. The changing phase is different between males and females, and this difference is significant after birth. Moreover, MIS mRNA is expressed during the developmental period (prenatal) and also in the postnatal period. This finding indicates that MIS may play a significant role in the developmental stage and in growth after birth.

• Korean Journal of Veterinary Research
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• v.40 no.2
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• pp.237-245
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• 2000

The regional distribution and relative frequency of somatostatin-immunoreactive cells in the gastrointestinal tract were studied during the postnatal development(1 day old, 1 month old, 6-month-old and adult) of the Korean native goat by immunohistochemical methods. Somatostatin-immunoreactive cells were found in the entire gastrointestinal tract and were most predominant in the fundic gland region except for the pyloric gland region of the 1 day old. The number of these cells was observed to decrease along the gastrointestinal tract and to decrease according to the increase with age in all postnatal stages. In this study, immunoreactive cells revealed the differences of regional distribution and the relative frequency in the gastrointestinal tract during postnatal development. These results suggest that although the functional significance of fetal endocrine cells remains unknown, this was caused by changing of feeding habits and physiological conditions during different ages.

• Development and Reproduction
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• v.23 no.3
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• pp.213-221
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• 2019

The epididymal fat of mouse is a part of visceral fat deposit and is divided into the distal or proximal part based on its histochemical characteristics. Even though the formation of the epididymal fat pad begins before the birth, a detailed adipogenic procedure of the epididymal fat has not been revealed. The epididymal fat pad becomes enlarged and expended with age, and expressional changes of numerous genes are associated with the maturation of fat tissues. In the present research, expressional patterns of adipose tissue-related genes in the distal epididymal fat of mouse at 2, 5, 8, and 12 months of postnatal age were determined by a quantitative real-time polymerase chain reaction (PCR) analysis. The lowest transcript levels of fatty acid binding protein 4 (Fabp4), lipoprotein lipase (Lpl), delta like non-canonical Notch ligand 1 (Dlk1), peroxisome proliferator-activated receptor gamma (Pparg), leptin (Lep), adiponectin (Adipoq), and resistin (Retn) were detected at 2 months of age, except fatty acid synthase (Fasn) showing the lowest level at 5 months of age. Even though expression of Lep and Fabp4 were gradually increased until 12 months of age, significant increases of Pparg and Adipoq transcript levels were continued until 8 months of age. The transcript levels of Lpl, Rent, Dlk1, and Fasn were significantly increased at 8 months of age, compared with those at 2 months of age. The current findings suggest that the expansion of the distal epididymal fat of mouse during postnatal period would be companied with differential expression of various adipocyte-associated molecules.

• Korean Journal of Environmental Biology
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• v.22 no.4
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• pp.550-558
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• 2004

The effects of postnatal exposure to octylphenol(OP) on the expressions of the steroidogenic enzymes and testosterone production were evaluated. Postnatal male mice (15-day-old) were injected with 2 or 20mg $kg^{-l}$ body weight (BW) of OP for 5 days and sacrificed on postnatal day 21. Testosterone concentration was measured by radioimmunoassay and the expressions of the testicular genes were determined by RT-PCR analyses. Significant reductions in the mean body and testis weight were observed in the OP treated animals. No marked alteration in the histological structure of the testis were observed, however, slight reduction in the seminiferous tubule diameter and the number of Leydig cells and several pyknotic cells could be identified in the 20 mg $kg^{-l}$ BW of the OP treated animals. Serum testosterone concentration was dramatically reduced and the mRNA expressions of the steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450scc) and $17\beta$-hydroxylase/Cl7-20 lyase $(P450_{17\alpha})$ were decreased. No significant changes of the gene expressions of the steroidogenic factor-l (SF-I) and estrogen and androgen receptor after the OP treatment showed that the decreased expressions of the steroidogenic enzymes in the present study did not correlate with these genes. Altogether, the present study demonstrates that postnatal treatment of OP inhibits steroidogenesis by decreasing the transcriptional expressions of the StAR and steroidogenic enzymes. The alteration in steroidogenesis may adversely affect the normal development of the testis and sper- matogenesis.