• Animal cells and systems
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• v.12 no.4
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• pp.313-319
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• 2008

The ultrastructure of oocytes during oogenesis and oocyte degeneration associated with follicle cells in female Sinonovacula constricta(Lamarck, 1818) were investigated by electron microscope observations. Ovarian follicles are surrounded by a matrix of vesicular connective tissue cells(VCT cells). VCT cells contain large quantities of glycogen particles and several lipid droplets in their cytoplasm. It is suggested that VCT cells act as a source of nutrients for vitellogenesis during oogenesis. In early vitellogenic oocytes, several coated vesicles, which appear at the basal region of the oocyte, lead to the formation of membrane-bound vesicles via endocytosis. The uptake of nutritive materials in coated vesicles formed by endocytosis appears through the formation of coated pits on the oolemma during vitellogenesis. During the late stage of oogenesis, yolk precursors(yolk granules), mitochondria and lipid droplets are present in the cytoplasm of late vitellogenic oocytes. In particular, proteinaceous yolk granules containing several different components are intermingles and form immature yolk granules. In the mature oocyte, small immature yolk granules are intermingled and form large mature yolk granules. Vitellogenesis occurs through a process of autosynthesis, involving combined activity of the Golgi complex, mitochondria and rough endoplasmic reticulum in the cytoplasm of vitellogenic oocytes. The process of heterosynthesis is where extraovarian precursors are incorporated into oocytes by endocytosis at the basal region of early vitellogenic oocytes before the formation of the vitelline coat. Follicle cells appear to play an important role in vitellogenesis and oocyte degeneration. The functions of attached follicle cells to the oocyte during oocyte degeneration are phagocytosis and digestion of phagosomes originating from oocyte degeneration. After digestion of phagosomes, it is assumed that the function of follicle cells can permit a transfer of yolk precursors necessary for vitellogenesis and allows for the accumulation of glycogen and lipid during oocyte degeneration, which can be employed by vitellogenic oocytes. Follicle cells of S. constricta may possess a lysosomal system for induction of oocyte breakdown and might resorb phagosomes in the cytoplasm for nutrient accumulation during oocyte degeneration.

• Journal of Korean Society on Water Environment
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• v.31 no.2
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• pp.181-195
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• 2015

Algal blooms in lakes are one of major environmental issues in Korea. A three-dimensional, hydrodynamic and water quality model was developed and tested in Lake Euiam to assess the performance and limitations of numerical modeling with multiple algal groups using field data commonly collected for algal management. In this study, EFDC was adopted as the basic model framework. Simulated vertical profiles of water temperature, dissolved oxygen and nutrients monitored at five water quality monitoring stations from March to October 2013, which are closely related to algal dynamics simulation, showed good agreement with those of observed data. The overall spatio-temporal variations of three algal groups were reasonably simulated against the chlorophyll-a levels of those estimated from the limited monitoring data (chlorophyll-a level and cell numbers of algal species) with the RMSEs ranging from 2.6 to $17.5mg/m^3$. Also, note that $PO_4-P$ level in the water column was a key limiting factor controlling the growth of three algal groups during most of simulation period. However, the algal modeling results were not fully attainable to the levels of observation during short periods of time showing abrupt increase in algae throughout the lake. In particular, the green algae/cyanobacteria and diatom simulations were underestimated in late June to early July and early October, respectively. The results shows that better understanding of internal algal processes, neglected in most algal modeling studies, is necessary to predict the sudden algal blooms more accurately because the concentrations of external $PO_4-P$ and specific algal groups originated from the tributaries (mainly, dam water releases) during the periods were too low to fully capture the sharp rise of internal algal levels. In this respect, this study suggests that future modeling efforts should be focused on the quantification of internal cycling processes including vertical movement of algal species with respect to changes in environmental conditions to enhance the modeling performance on complex algal dynamics.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.5
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• pp.389-399
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• 2015

Zinc has been considered as a vital constituent of proteins, including enzymes. Mobile reactive zinc ($Zn^{2+}$) is the key form of zinc involved in signal transductions, which are mainly driven by its binding to proteins or the release of zinc from proteins, possibly via a redox switch. There has been growing evidence of zinc's critical role in cell signaling, due to its flexible coordination geometry and rapid shifts in protein conformation to perform biological reactions. The importance and complexity of $Zn^{2+}$ activity has been presumed to parallel the degree of calcium's participation in cellular processes. Whole body and cellular $Zn^{2+}$ levels are largely regulated by metallothioneins (MTs), $Zn^{2+}$ importers (ZIPs), and $Zn^{2+}$ transporters (ZnTs). Numerous proteins involved in signaling pathways, mitochondrial metabolism, and ion channels that play a pivotal role in controlling cardiac contractility are common targets of $Zn^{2+}$. However, these regulatory actions of $Zn^{2+}$ are not limited to the function of the heart, but also extend to numerous other organ systems, such as the central nervous system, immune system, cardiovascular tissue, and secretory glands, such as the pancreas, prostate, and mammary glands. In this review, the regulation of cellular $Zn^{2+}$ levels, $Zn^{2+}$-mediated signal transduction, impacts of $Zn^{2+}$ on ion channels and mitochondrial metabolism, and finally, the implications of $Zn^{2+}$ in health and disease development were outlined to help widen the current understanding of the versatile and complex roles of $Zn^{2+}$.

• Journal of the Korean Chemical Society
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• v.35 no.4
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• pp.389-396
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• 1991

The pre-concentration and determination of ultratrace arsenic in water samples was studied by the precipitate flotation technique. The arsenic in 1.0l of water sample, in which all suspended materials were filtered out, was coprecipitated together with La(OH)$_3$ precipitates at pH 8.5${\pm}$0.1. After the precipitate was made to be hydrophobic by adding mixed surfactant of 1 : 8 mole ratio of sodium oleate and sodium dodecyl sulfate, it was floated with the aid of tiny bubbles of nitrogen gas in a flotation cell. The floated precipitate was quantitatively collected on a micropore glass filter by the suction, dissolved with small volume of 1.0M sulfuric acid, and accurately diluted to 25.00ml with a de-ionized water. Total arsenic was spectrophotometrically determinated by forming silver diethyldithiocarbamate complex of arsine generated from arsenic in the concentrated solution. The calibration curve was linear up to 20ng/ml in the original solution. Analytical results showed that contents of arsenic in a campus wastewater and a river water were 8.2ng/ml and l.0ng/ml, respectively, and their recoveries were 93${\%}$ and 90${\%}$ in water samples which a given amount of arsenic was added into. From above result, it could be concluded that this method was applicable to the determination of arsenic in various kinds of water at low ng/ml levels.

• Journal of Gastric Cancer
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• v.1 no.2
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• pp.92-99
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• 2001

Purpose: E-cadherin is an adhesion molecule essential for tight connection between cells, forming the cadherin/catenin complex. Truncated $\beta$-catenin disrupts the interaction between E-cadherin and $\alpha$-catenin, leading to the loss of intercellular adhesion. Met protein, the hepatocyte growth factor receptor, plays important roles in signal transduction. We investigated the relationships between the expressions of E-cadherin, $\beta$-catenin, and c-met protein and the clinicopathological and prognostic parameters in gastric adenocarcinomas. Materials and Methods: The patterns of E-cadherin, $\beta$-catenin, and c-met protein expression were studied using immunohistochemistry in formalin-fixed, paraffin-embedded archival tissues from 76 surgically resected gastric adenocarcinomas. Results: Increased expressions of E-cadherin, $\beta$-catenin, and c-met were more significantly correlated in early gastric cancers (EGC) than in advanced gastric cancers (AGC) (P=0.002, P=0.003 and P=0.026). The positive immunoreactivities of all three markers were markedly lower in signet ring-cell type and poorly differentiated type lesions than in intestinal-type lesions. Decreased expression of the $\beta$-catenin protein correlated well with increased tumor invasion depth (P=0.039), and increased lymph node metastasis correlated well with reduced expression of c-met (P=0.046). Conclusion: In gastric cancers, reduced expressions of the E-cadherin, $\beta$-catenin, and c-met proteins may play some role in poorer tumor differentiation, deeper tumor invasion, and increased lymph node metastasis. Also, the c-met gene is thought to play a specific role in the mechanism of the yet unknown catenin action.

• Investigative Magnetic Resonance Imaging
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• v.19 no.4
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• pp.231-236
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• 2015

A 17-year-old girl presented with complaints of headache and decreasing vision of one month's duration, without any history of fever, weight loss, or any evidence of an immuno-compromised state. Her neurological examination was normal, except for papilledema. Laboratory investigations were within normal limits, except for a slightly increased Erythrocyte Sedimentation Rate (ESR). Non-contrast computerized tomography of her head revealed complex mass in left frontal lobe with a concentric, slightly hyperdense, thickened wall, and moderate perilesional edema with mass effect. Differential diagnoses considered in this case were pilocytic astrocytoma, metastasis and abscess. Magnetic resonance imaging (MRI) obtained in 3.0 Tesla (3.0T) scanner revealed a lobulated outline cystic mass in the left frontal lobe with two concentric layers of T2 hypointense wall, with T2 hyperintensity between the concentric ring. Moderate perilesional edema and mass effect were seen. Post gadolinium study showed a markedly enhancing irregular wall with some enhancing nodular solid component. No restricted diffusion was seen in this mass in diffusion weighted imaging (DWI). Magnetic resonance spectroscopy (MRS) showed increased lactate and lipid peaks in the central part of this mass, although some areas at the wall and perilesional T2 hyperintensity showed an increased choline peak without significant decrease in N-acetylaspartate (NAA) level. Arterial spin labelling (ASL) and dynamic susceptibility contrast (DSC) enhanced perfusion study showed decrease in relative cerebral blood volume at this region. These features in MRI were suggestive of brain abscess. The patient underwent craniotomy with excision of a grayish nodular lesion. Abundant acid fast bacilli (AFB) in acid fast staining, and epithelioid cell granulomas, caseation necrosis and Langhans giant cells in histopathology, were conclusive of tubercular abscess. Tubercular brain abscess is a rare manifestation that simulates malignancy and cause diagnostic dilemma. MRI along with MRS and magnetic resonance perfusion studies, are powerful tools to differentiate lesions in such equivocal cases.

• Archives of Pharmacal Research
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• v.29 no.8
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• pp.666-676
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• 2006

Gangliosides are widely distributed in mammalian cells and play important roles in various functions such as cell differentiation and growth control. In addition, diabetes and obesity cause abnormal development of reproductive processes in a variety of species. However, the mechanisms underlying these effects, and how they are related, are not fully understood. This study examined whether the differential expression of gangliosides is implicated in the abnormal follicular development and uterine architecture of streptozotocin (STZ)-induced and db/db diabetic mice. Based upon the mobility on high-performance thin-layer chromatography, mouse ovary consisted of at least five different ganglioside components, mainly gangliosides GM3, GM1, GD1a and GT1b, and diabetic ovary exhibited a significant reduction in ganglioside expression with apparent changes in the major gangliosides. A prominent immunofluorescence microscopy showed a dramatic loss of ganglioside GD1a expression in the primary, secondary and Graafian follicles of STZ-induced and db/db diabetic mice. A significant decrease in ganglioside GD3 expression was also observed in the ovary of db/db mice. In the uterus of STZ-induced diabetic mice, expression of gangliosides GD1a and GT1b was obviously reduced, but gangliosides GM1, GM2 and GD3 expression was increased. In contrast, the uterus of db/db mice showed a significant increase in gangliosides GM1, GD1a and GD3 expression. Taken together, a complex pattern of ganglioside expression was seen in the ovary and uterus of normoglycemic ICR and $db/^+$ mice, and the correspoding tissues in diabetic mice are characterized by appreciable changes of the major ganglioside expression. These results suggest that alterations in ganglioside expression caused by diabetes mellitus may be implicated in abnormal ovarian development and uterine structure.

• Journal of the Korean Chemical Society
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• v.55 no.1
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• pp.70-80
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• 2011

Two new palladium (II) complexes, [Pd (phen)(pip-dtc)]$NO_3$ and [Pd(phen)(mor-dtc)]$NO_3$, (where phen is 1,10-Phenantroline, pip-dtc is piperidinedithiocarbamate anion and mor-dtc is morpholinedithiocarbamate anion) have been synthesized and characterized by elemental analysis, spectroscopic studies (FT-IR, $^1H$ NMR, UV-Vis) and conductance measurement. In these complexes, the dithiocarbamate ligands coordinate with Pd (II) center as bidentate with two sulfur atoms. These two complexes have been tested against chronic myelogenous leukemia cell line, K562. They show $IC_{50}$ values less than cisplatin and thus the mode of binding of the complexes to calf thymus DNA (CT-DNA) were investigated by ultraviolet difference and fluorescence spectroscopy. They can denature DNA, exhibit cooperative binding and intercalate into DNA. Several binding and thermodynamic parameters are also described.

• Journal of Life Science
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• v.21 no.12
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• pp.1789-1794
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• 2011

Dendritic cells (DCs) are professional antigen-presenting cells playing key roles in immune sentinels as initiators of T-cell responses against microbial pathogens and tumors. Sarijang, a folk sauce containing extracts of Rhynchosia nulubilis, Ulmus davidiana roots, Allium sativum, and Rhus Verniaiflura bark, has been used as a nonspecific immunostimulant for cancer patients. However, little is known about its immunomodulating effects or their mechanisms. In this study, we investigated whether sarijang induces phenotypic and functional maturation of DCs. For this study, murine bone marrow-derived myeloid DCs were cultured in the presence of interleukin-4 (IL-4) and granulocyte-macrophage colony stimulating factor (GM-CSF), and the generated immature DCs were stimulated with sarijang or lipopolysaccharide (LPS). Our data indicated that sarijang significantly enhanced the expression of co-stimulatory molecules (CD80 and CD86) as well as major histocompatibility complex (MHC) II, as did LPS. The results provide new insight into the immunopharmacology of sarijang and suggest a novel approach to the manipulation of DC for therapeutic application.

• Applied Microscopy
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• v.30 no.1
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• pp.101-111
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• 2000

In this study, the distribution of lectin receptors in Paragonimus westermani tissue was explored using colloidal gold label complexed with lectin WGA purified from wheat germ (Triticum vulgare). The lectin WGA gold complex, shown to recognize GlcNAc (N-acetylgalactosamine) and NeuNAc (N-acetylneuraminic acid) regions, was applied to detect binding sites in Lowicryl HM 20 sections viewed under electron microscope. Labeled sections of the metacercaria revealed gold particles specifically distributed on the tegumental syncytium and lamella of the excretory canal. Labeling of young adult tissue was then quantified and compared to that of adult worm tissue. Adult worm tissue sections resulted in specific gold particle distribution on the lamella of caecal epithelium and excretory canal. These results indicate that lectin WGA receptors are located in the tegumental syncytium and lamella of the excretory canal of the metacercariae, and in the lamella of the caecum and excretory canal of the young adult and adult. Therefore, the GlcNAc and NeuNAc regions in the tegumental syncytium appear to be functionally associated with cell-recognition and protection from the immune system of the host, and linked with membrane transport and absorption of nutrients in the lamella of the excretaory canal and caecal epithelia.