• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2395-2407
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• 2022

The sodium-cooled fast reactor is among the innovative nuclear technologies selected in the framework of the development of Generation IV concepts, allowing the irradiation of uranium-plutonium mixed oxide fuels (MOX). A fundamental step for the safety assessment of MOX-fuelled pins for fast reactor applications is the evaluation, by means of fuel performance codes, of the integral thermal-mechanical behaviour under irradiation, involving the fission gas behaviour and release in the fuel-cladding gap. This work is dedicated to the performance analysis of an inner-core fuel pin representative of the ASTRID sodium-cooled concept design, selected as case study for the benchmark between the GERMINAL and TRANSURANUS fuel performance codes. The focus is on fission gas-related mechanisms and integral outcomes as predicted by means of the SCIANTIX module (allowing the physics-based treatment of inert gas behaviour and release) coupled to both fuel performance codes. The benchmark activity involves the application of both GERMINAL and TRANSURANUS in their "pre-INSPYRE" versions, i.e., adopting the state-of-the-art recommended correlations available in the codes, compared with the "post-INSPYRE" code results, obtained by implementing novel models for MOX fuel properties and phenomena (SCIANTIX included) developed in the framework of the INSPYRE H2020 Project. The SCIANTIX modelling includes the consideration of burst releases of the fission gas stored at the grain boundaries occurring during power transients of shutdown and start-up, whose effect on a fast reactor fuel concept is analysed. A clear need to further extend and validate the SCIANTIX module for application to fast reactor MOX emerges from this work; nevertheless, the GERMINAL-TRANSURANUS benchmark on the ASTRID case study highlights the achieved code capabilities for fast reactor conditions and paves the way towards the proper application of fuel performance codes to safety evaluations on Generation IV reactor concepts.

• Development and Reproduction
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• v.17 no.2
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• pp.141-147
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• 2013

Keeping the intact germinal vesicle (GV) is essential for maintaining the capacity of mammals including human. It is maintained by very complex procedures along with folliculogenesis and is a critical step for getting competent oocyte. So far, a few mechanisms involved in folliculogenesis are known but GV arrest mechanisms are largely unrevealed. Cyclic AMP, a adenosine derived substance, have been used as inhibitor of germinal vesicle breakdown as a putative oocyte maturation inhibitor. In this study, we examined the potency of adenosine as GV maintainer and a possible signaling mediator for that. A1, A2b, and A3 were detected in cumulus cells of cumulus enclosed-oocyte (CEO). Intact of germinal vesicle was not kept like in follicle but the spontaneous maturation was inhibited by exogenous adenosine. It is inhibited with concentration dependent manners. Intracellular calcium level of cumulus was extensively increased after adenosine treatment. Based on these results it is suggested that one of the pathway for GV arrest by adenosine and its receptors is calcium mediated signaling pathway in CEO.

• Reproductive and Developmental Biology
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• v.34 no.3
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• pp.169-173
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• 2010

Correlations between cumulus cells and germinal vesicle (GV) chromatin configuration were examined in porcine oocytes. Cumulus-oocyte complexes (COCs) were collected from 2~6 mm follicles and divided into three categories according to cumulus cell morphology. "A" group was compacted COCs with more than three cumulus cell layers. "B" group was COCs with less cumulus cell layers than "A" group. "C" group was COCs with one or less layer of cumulus cells. Cumulus cells were removed 0.1% hyaluronidase, and denuded oocytes were stained with Hoechst 33342. GV chromatin configuration was classified into GV-Con and GV-Dis. GV-Con meant that a nucleus was surrounded by condensed chromatin in a ring. GV-Dis meant that filamentous chromatin clumps were distributed in nucleus. The proportion (80.2%) of GV-Con in "A" group was significantly higher than "B" (62.0%) or "C" (44.9%). The proportion (55.1%) of GV-Dis in "C" group was significantly higher than "A" (19.8%) or "B" (38.0%). The meiotic competence of COCs was examined after 44 h culture. The proportion (90.0%) of oocytes reaching to metaphase II (M-II) in "A" group was significantly higher than "B" (76.5%) or "C" (45.5%). In conclusion, oocytes with good quality cumulus cell layers are synchronized early GV stage, and early GV stage is important for meiotic competence in pigs.

• IMMUNE NETWORK
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• v.3 no.3
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• pp.176-181
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• 2003

Background: The molecular basis of follicular dendritic cells (FDC)-germinal center (GC) B cell interaction is largely unknown, although this cellular interaction is thought to be important for the whole process of GC B cell differentiation. Methods: Using FDC-like cells, HK, and highly purified GC B cells, we attempted to identify the molecules that play critical roles in the interactions between FDC and B cells. GC B cells were co-cultured with HK cells and soluble CD154 in the presence or absence of various function-blocking monoclonal antibodies to examine their effect on GC B cell binding to HK cells and B cell proliferation. Results: Anti-CD11a and anti-CD54 antibodies inhibited GC B cell binding to HK cells while anti-CD49d and anti-CD106 antibodies did not. GC B cell proliferation was not impaired by the disruption of GC B cell-HK cell adherence. Conclusion: Our results suggest that CD11a/CD18-CD54 interactions play an important roles in the initial binding of GC B cells to FDC and diffusible growth factors from FDC may be responsible the massive proliferation of GC B cells.

• Proceedings of the Korea Society of Poultry Science Conference
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• 1999.11a
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• pp.11-33
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• 1999

This study was conducted to determine the embryonic stages for the isolation of the highest number of PGCs and to improve PGCs enrichment method. The primordial germ cells(PGCs) from different sources of chick embryos were isolated. The embryonic stage having the highest number of PGCs from each sources was selected ; 1-day-old embryos for germinal crescent (stage 6-8), 2.5-day-old embryos for blood (stage 17-18) and 5.5-day-old embryos for gonad (stage 27-28). The number of PGCs from one embryonic germinal crescent, blood and gonad was about 87$\pm$1.8, 103$\pm$4.0, and 932$\pm$10.9, respectively. The viability of PGCs after Ficoll from each sources was similar, showing approximately 70%. the PGCs enrichment method was improved using Ficoll density gradient centrifugation. After this step the purity of PGCs from germinal crescent, blood, and gonad was 45$\pm$9.10%, 85$\pm$1.18%, and 86$\pm$0.19%, respectively. Also, PGCs were picked up by mouth pipette to improve the purity. This improved method for the separation of PGCs from different sources will serve as a useful too to preserve the foundation stocks of poultry and to produce germline chimeras.

• Investigative Magnetic Resonance Imaging
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• v.21 no.1
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• pp.56-60
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• 2017

Progressive transformation of germinal centers (PTGC) is an atypical feature seen in lymph nodes with unknown pathogenesis. PTGC most commonly presents in adolescent and young adult males as solitary painless lymphadenopathy with various durations. Cervical nodes are the most commonly involved ones while involvements of axillary and inguinal nodes are less frequent. PTGC develops extremely rarely in other locations. We report a rare case of solitary mass present in the presacral space. The mass as subsequently proven to be PTGC. To the best of our knowledge, PTGC in the presacral space has not been previously reported in the literature.

• Journal of Korean Neurosurgical Society
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• v.56 no.4
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• pp.334-337
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• 2014

Objective : The purpose of this study is to identify the risk factors associated with the development of germinal matrix-intraventricular hemorrhage (GM-IVH) and the relationship of the severity of disease and prematurity. Methods : A total of 168 premature neonates whose birth weight ${\leq}1500g$ or gestational age ${\leq}34$ weeks were examined by cranial ultrasound (CUS) for detection of GM-IVH among the babies admitted between January 2011 and December 2012 in our medical center neonatal intensive care unit. The babies were divided into two groups : GM-IVH and non-IVH. Clinical presentations, precipitating factors of the patients and maternal factors were analyzed. Results : In univariate analysis, gestational age, birth weight, delivery method, presence of premature rupture of membrane (PROM) and level of sodium and glucose were statistically meaningful factors (p<0.05). But only two factors, gestational age and presence of patent ductus arteriosus (PDA) were statistically meaningful in multivariate logistic regression (p<0.05). Delivery method [normal vaginal delivery (NVD) to Caeserean section] was borderline significant (p<0.10). Conclusion : Presence of PDA and gestational age were the important risk factors associated with development of GM-IVH.

• Reproductive and Developmental Biology
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• v.29 no.4
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• pp.223-227
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• 2005

In vitro maturation of porcine immature cumulus-enclosed oocytes can be enhanced by co-incubation with spermatozoa even before fertilization. The aim of this study was to determine whether the addition of spermatozoa into the culture medium can stimulate the meiosis resumption of porcine cumulus-enclosed oocytes arrested at germinal vesicle (GV). Cumulus-enclosed oocytes (CEOs) were collected from follicles of 3 to 5mm diameter. Porcine CEOs were cultured in tissue culture medium containing various meiosis inhibitors and spermatozoa. Oocytes were examined for evidence of GV and GV breakdown after 24 h culture. After 24 h culture $43.8\%$ of oocytes cultured in only TCM 199 remained at GV stage whereas $56.2\%$ of oocytes were able to resume meiosis. When porcine CEOs were cultured in the medium with meiosis inhibitor such as, dibutyryl cAMP (dbcAMP) and forskolin (Fo), more than $90\%$ of oocytes were not able to resume meiosis. However, co-culture of porcine CEOs with spermatozoa was able to overcome the inhibitory effect of dbcAMP and Fo. Irrespective of the presence of 3-isobutyl-1-methylxanthine (IBMX), no difference was observed in the proportion of oocyte reached germinal vesicle breakdown (GVBD). The present study suggests that dbcAMP and Fo prevent the spontaneous maturation of competent oocyte in culture after isolation from follicles and that mammalian spermatozoa contain a substance(s) that improves meiosis resumption in vitro of porcine cumulus-enclosed oocytes.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.4
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• pp.368-372
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• 2011

Progressive transformation of germinal centers (PTGC) is mostly a disease of young adults and it presents as unexplained, asymptomatic, localized or generalized lymphadenopathy that is usually persistent or recurrent over a period of many years. PTGCs are larger than regular germinal centers and they contain a variable proportion of small mantle zone lymphocytes and so they become progressively transformed and they may result in the loss of clear demarcation between them and the mantle zone. PTGC may resemble the nodules of nodular lymphocyte predominant Hodgkin's disease (NLPHD) and it may be mistaken for NLPHD. Histological and immunohistochemical studies are helpful in differentiating these diseases. Because of the relatively frequent recurrences of PTGC, follow-up and repeat biopsy are indicated. Although PTGC is not considered to be a premalignant condition, PTGC may occur prior to, concurrent with or following NLPHD. This emphasizes the need for ongoing follow-up and repeat biopsy. Although PTGC is reported in 3.5% to 10% of the cases of chronic nonspecific lymphadenopathy, oral & maxillofacial surgeons are not widely aware of this condition and its clinical implications. Herein, we present a case of PTGC. A 24-year-old male without any history of immunodeficiency or autoimmune disease was admitted to the Department of Oral & Maxillofacial surgery at Ulsan University Hospital for evaluation of a right submandibular swelling. He had another mass on the right thigh that was noticed about 1 year ago. The submandibular lesion was completely resected and biopsied. The histological findings and immunohistochemical stains (CD3, CD15, CD20, CD30, CD57, BCL-2, EMA) were consistent with PTGC. He was followed up without any other complaints for 9 months.

• IMMUNE NETWORK
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• v.14 no.5
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• pp.227-236
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• 2014

Understanding germinal center reactions is crucial not only for the design of effective vaccines against infectious agents and malignant cells but also for the development of therapeutic intervention for the treatment of antibody-mediated immune disorders. Recent advances in this field have revealed specialized subsets of T cells necessary for the control of B cell responses in the follicle. These cells include follicular regulatory T cells and Qa-1-restricted cluster of differentiation $(CD)8^+$ regulatory T cells. In this review, we discuss the current knowledge related to the role of regulatory T cells in the B cell follicle.