• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2003년도 춘계학술대회
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• pp.178-179
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• 2003

The testis is composed of four cell types like supporting cells, steroid-producing cells, connective tissue cells and germ cells. Apoptosis is a common phenomenon during spormatogenesis. Apoptosis of germ cells can also be induced by exposure to radiation. Previous studies have shown that most types of germ cells are rather radiosensitive while somatic cells in testis are much more radio-resistant. The somatic cells in testis are divided to mainly Sertoli and Leydig cells. Though somatic cells are more radio-resistant than germ cells, radiation can induce the impairment of their function. This damaged function of somatic cells may accelerates degeneration of germ cell indirectly. Tn the present study, we have examined the apoptotic effect of mouse testis and irradiation effect of steroidogenesis of Leydig cells after irradiation.

• 한국임상수의학회지
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• 제8권1호
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• pp.1-10
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• 1991

The B-lymphocyte differentiation from committed B-cell progenitors to antibody-secreting cells was discussed. B-cell progenitors derived from hematopoietic stem cells undergo the rearrangement of immunoglobulin(Ig) gene. The earliest cells as B-cell precursors have cytoplasmic Is(${\mu}$ chain). The entire Is molecule is expressed on the surface after synthesis of L chain. The resting B cells(Go stage) stimulated by binding antigen via Ig-receptors are activated(G$_1$ stage) and followed by proliferation(S stage), coupled with further selection(affinity maturation. class switch). The production of antibody against a particular antigen depends on the activation of B cells with surface Is capable of reacting with that antigen. This process does not occur in isolation but is controlled by helper and suppressor T cells and antigen presenting cells(APC). The mechanism of T cell-dependent B-cell response for production of antibody is largely explained by the cell to cell cooperation and soluble helper factors of T cells. 1) The antigen specific B cells and helper T cells are linked by Is-receptors, leading to the delivery of helper signals to the B cells. 2) Helper T cells recognize the processed antigen-derived peptides with the MHC class II molecules(la antigen) and is stimulated to secrete B-cell proliferation and differentiation factors which activate B cells of different antigenic specificity. The two models are shown currently 1) At low antigen concentration, only the antigen-specific B cell binds antigen and presents antigen-derived peptides with la molecules to helper T cells, which are stimulated to secrete cytokines(IL-4, IL-5, etc.) and 2) At high antigen concentration, antigen-derived peptides are presented by specific B cells, by B cells that endocytose the antigens, as well as by APC Cytokines secreted from helper T cells also lead to the activation of B cells and even bystander B cells in the on- vironmment and differentiate them into antibody-secreting plasma cells.

• Reproductive and Developmental Biology
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• 제32권2호
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• pp.105-110
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• 2008

The endogenous retrovirus-like elements (HERVs) found on several human chromosomes are somehow involved in gene regulation, especially during the transcription level. HERV-H, located on chromosome Xp22, may regulate gastrin-releasing peptide receptor (GRPR) in connection with diverse diseases. By suppression subtractive hybridization screen on SV40-immortalized lung fibroblast (WI-38 VA-13), we discovered that expression of HERV-HX2, a clustered HERV-H sequence on chromosome X, was upregulated in immortalized lung cells, compared to that of normal cells. Expression of HERV-HX2 was then analyzed in various cell lines, including normal somatic cells, cancer cells, SV40-immortalized cells, and undifferentiated and differentiated human embryonic stem cells. Expression of HERV-HX2 was specifically upregulated in continuously-dividing cells, such as cancer cells and SV40-immortalized cells. Especially, HERV-HX2 in HeLa cells was highly upregulated during the S phase of the cell cycle. Similar results were obtained in hES cells, in which undifferentiated cells expressed more HERV-HX2 mRNA than differentiated hES cells, including neural precursor and endothelial progenitor cells. Taken together, our results suggest that HERV-HX2 is upregulated in cancer cells and undifferentiated hES cells, whereas downregulated as differentiation progress. Therefore, we assume that HERV-HX2 may playa role on proliferation of cancer cells as well as differentiation of hES cells in the transcriptional level.

• 대한수의학회지
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• 제45권4호
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• pp.501-505
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• 2005

Immu-Forte composed of chitosan, ${\beta}-glucan$, manno-oligosaccharide and pangamic acid was evaluated for its effectiveness as a nonspecific immunostimulator in mice. The effects of Immu-Forte were determined by analysis of cytokines using ELISA and phenotype of leukocyte subpopulations using monoclonal antibodies specific to mouse leukocyte differentiation antigens and flow cytometry. All T cells, all B cells, CD4 T cells, CD8 T cells, macrophages, IL-2, IL-4, IL-12 and IFN-r in Immu-Forte A-treated group increased in 1 months posttreatment and were significantly higher (p < 0.05) than that of control at 1 months posttreatment. All T cells, all B cells, CD4 T cells, CD8 T cells, macrophages and IL-2 in Immu-Forte EX-treated low and middle dose groups increased in 1 months posttreatment and were significantly higher (p < 0.05) than that of control at 1 months posttreatment. In the Immu-Forte soybean-treated group, NK cells and IL-4 were significantly higher in middle dose-treated group, and IL-2, IL-4 and IFN-r were significantly higher in low dose-treated group. In the Immu-Forte F-treated group, all T cells, all B cells, CD4 T cells, CD8 T cells, macrophages, NK cells, IL-2, IL-4, IL-12 and IFN-r in high dose-treated group and all T cells, all B cells, CD4 T cells, CD8 T cells, macrophages, IL-2, IL-4, IL-12 and IFN-r in middle dose-treated group and NK cells, IL-2, IL-4, IL-12 and IFN-r in low dose-treated group were significantly higher (p < 0.05) than that of control at 1 months posttreatment. In conclusion, this study has demonstrated that Immu-Forte had an immunostimulatory effect on mice through proliferation and activation of mouse immune cells.

• International Journal of Stem Cells
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• 제16권1호
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• pp.108-116
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• 2023

γδ T cells are a rare and unique prototype of T cells that share properties with natural killer cells in secondary lymphoid organs. Although many studies have revealed the function and importance of adult-derived γδ T cells in cancer biology and regenerative medicine, the low numbers of these cells hamper their application as therapeutic cell sources in the clinic. To solve this problem, pluripotent stem cell-derived γδ T cells are considered alternative cell sources; however, few studies have reported the generation of human pluripotent stem cell-derived γδ T cells. In the present study, we investigated whether lymphoid lineage γδ T cells were successfully generated from human pluripotent stem cells via hemogenic endothelium under defined culture conditions. Our results revealed that pluripotent stem cells successfully generated γδ T cells with an overall increase in transcriptional activity of lymphoid lineage genes and cytolytic factors, indicating the importance of the optimization of culture conditions in generating lymphoid lineage γδ T cells. We uncovered an initial step in differentiating γδ T cells that could be applied to basic and translational investigations in the field of cancer biology. Based on our result, we will develop an appropriate method to purify γδ T cells with functionality and it helpful for the study of basic mechanism of γδ T cells in pathophysiologic condition as well as clinic application.

• 대한수의학회지
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• 제39권4호
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• pp.689-697
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• 1999

The regional distribution and relative frequency of endocrine cells in the alimentary tract of the snake, Rhabdophis tigrinus tigrinus, were investigated by immunohistochemical method using 7 antisera. Chromogranin (Cg)-, glucagon-, somatostatin-, gastrin/cholecystokinin (Gas/CCK)-, serotonin-, bovine pancreatic polypeptide (BPP)-immunoreactive cells were identified in this study. Cg-immunoreactive cells were detected throughout the alimentary tract including the esophagus, with predominant frequency in the pylorus. Numerous immunoreactive cells were observed from the esophagus to the pylorus but a few cells were detected in the large intestine. Glucagon-immunoreactive cells were observed from the proximal portions to the distal portions of the small intestine. They were increased to the middle portions but thereafter decreased, and no cells were found in the terminal portions. Somatostatin-immunoreactive cells were restricted to the small intestine and these cells were decreased toward to distal portions of the small intestine. Gas/CCK-immunoreactive cells were detected in the pylorus and small intestine. They were most predominant in the pylorus and the proximal portions of the small intestine but thereafter decreased toward to the distal regions. Serotonin-immunoreactive cells were observed throughout the alimentary tract. They were most predominant in the pylorus and proximal portions of the small intestine but a few cells were observed in the large intestine. BPP-immunoreactive cells were restricted to the distal portions of the small intestine with rare frequency. No bombesin-immunoreactive cells were found in this study.

• 대한수의학회지
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• 제53권3호
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• pp.143-147
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• 2013

Ginsenoside Rp1 is one of ginseng saponins with chemotherapeutic activity. In this study, we investigated the effects of Rp1 on spleen cells. Spleen is a major immune organ consisted of crucial immune cells, such as T lymphocytes, B lymphocytes, natural killer cells, and some antigen-presenting cells. Although the anti-tumor potential of Rp1 was studied, the effects of Rp1 on immune cells have not investigated yet. A viability assay using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT), flow cytometric analysis, Western blot analysis were used to detect cellular changes on Rp1-treated spleen cells. MTT assay showed that Rp1 decreased the viability of spleen cells. To further investigate the effects of Rp1 on activated spleen cells, we treated lipopolysaccharide (LPS) as a representative inflammatory agent and Rp1 on spleen cells in a combination. The surface expression levels of activation markers for lymphocytes, CD25 and CD69 were measured. Apoptotic analysis revealed the cytotoxic effects of Rp1 on both na$\ddot{i}$ve and activated cells, and the expression pattern of some apoptosis-related proteins was correlated to apoptotic events of cells. Taken together, ginsenoside Rp1 increases the cellular death of spleen cells and also inhibits the LPS-induced activation of spleen cells.

• Applied Microscopy
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• 제25권1호
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• pp.30-47
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• 1995

The ultrastructural changes of adrenal chromaffin cells and ganglion cells in the adrenal gland of vacor-induced diabetic Mongolian gerbils were studied by electron microscopy. After one month of vacor-induced diabetes, some chromaffin cells were filled with dense bodies and large cytosomes with formy contents. Most of degenerating axon terminals were observed on chromaffin cells. A few macrophages were found among chromaffin cells at one month after induction. Several of these macrophages were filled with numerous phagosomes. After one month of vacor-induced diabetes, the ganglion cells showed increase in numbers of dense bodies and degenerating dendrites compared with the normal ganglion cells. Both electron dense and lucent types of degenerating axon terminals were found in interstitial space of the ganglion cells. Degenerating unmyelinated and myelinted axons contained dense and lamellar bodies. The satellite cells and macrophages with engulfed degenerated axon terminals were observed. After three months of vacor-induced diabetes, the unmyelinated and myelinated axons showed degenerative changes, whereas no structural changes could be demonstrated in adrenal ganglion and chromaffin cells. The satellite cells and macrophages containing partially digested debris were still commonly observed in the interstitial space of adrenal medulla. These results suggest that the degenerative changes occur in the adrenal ganglion cells as well as adrenal chromaffin cells of vacor-induced diabetic Mongolian gerbils.

• KSBB Journal
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• 제20권1호
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• pp.1-11
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• 2005

Recently, there has been extremely active in the research of stem cell biology. Stem cells have excellent potential for being the ultimate source of transplantable cells for many different tissues. Researchers hope to use stem cells to repair or replace diseased or damaged organs, leading to new treatments for human disorders that are currently incurable, including diabetes, spinal cord injury and brain diseases. There are primary sources of stem cells like embryonic stem cells and adult stem cells. Stem cells from embryos were known to give rise to every type of cell. However, embryonic stem cells still have a lot of disadvantages. First, transplanted cells sometimes grow into tumors. Second, the human embryonic stem cells that are available for research would be rejected by a patient's immune system. Tissue-matched transplants could be made by either creating a bank of stem cells from more human embryos, or by cloning a patient's DNA into existing stem cells to customize them. However, this is laborious and ethically contentious. These problems could be overcome by using adult stem cells, taken from a patient, that are treated to remove problems and then put back. Nevertheless, some researchers do not convince that adult stem cells could, like embryonic ones, make every tissue type. Human stem cell research holds enormous potential for contributing to our understanding of fundamental human biology. In this review, we discuss the recent progress in stem cell research and the future therapeutic applications.

• Molecules and Cells
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• 제21권1호
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• pp.7-20
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• 2006

The major event in human immunodeficiency virus type 1 (HIV-1) infection is the death of many cells related to host immune response. The demise of these cells is normally explained by cell suicide mechanism, apoptosis. Interestingly, the decrease in the number of immune cells, such as non-CD4+ cells as well as CD4+ T cells, in HIV infection usually occurs in uninfected bystander cells, not in directly infected cells. It has, therefore, been suggested that several soluble factors, including viral protein R (Vpr), are released from the infected cells and induce the death of bystander cells. Some studies show that Vpr interacts directly with adenine nucleotide translocator (ANT) to induce mitochondrial membrane permeabilization (MMP). The MMP results in release of some apoptogenic factors such as cytochrome-c (cyt-c) and apoptosis-inducing factor (AIF). Vpr also has indirect effect on mitochondria through enhancing the level of caspase-9 transcription and suppressing nuclear factor-kappa B (NF-${\kappa}B$). The involvement of p53 in Vpr-induced apoptosis remains to be studied. On the other hand, low level of Vpr expression has anti-apoptotic effect, whereas it's high level of expression induces apoptosis. Extracellular Vpr also exhibits cytotoxicity to uninfected bystander cells through apoptotic or necrotic mechanism. The facts that Vpr has cytotoxic effect on both infected cells and bystander cells, and that it exhibits both proand anti-apoptotic activity may explain its role in viral survival and disease progression.