• Magazine of the Korean Society of Agricultural Engineers
• /
• v.44 no.3
• /
• pp.136-145
• /
• 2002

Monitoring data from agricultural reservoirs throughout the country were analyzed to evaluate the limiting factor fur algal growth and relationships between Chl-a, total phosphorus (TP), and total nitrogen (TN). Total 394 reservoirs ranging from below 500 ㎥ to over 50 million ㎥ in storage volume were monitored from 1990 to 2000 with respect to TP, W, Chl-a, and their annual mean values were used fur the analysis. Based on N/P ratio, the dominant limiting factor for algal growth was turned out to be phosphorus in agricultural reservoirs (about 83%). Therefore, the proper managements of phosphorus in the agricultural watershed appear to be crucial to prevent excessive on algal growth. The effects of phosphorus and nitrogen ware most eminent during the summer period. And the effect of nutrients on the algal biomass (Chl-a) development appeared to be greater in smaller the reservoirs than in larger ones. Generally, Chl-a and TP demonstrated a close relationship while that of Chl-a and TN showed less correlationship. Chl-a and chemical oxygen demand (COD) also showed a good relationship. Beth ratios of Chl-a / TP and Chl-a / COD relationships were within the range of literature values. Quantitative analysis of TP and COD is relatively convenient compared to that of Chl-a, and the relationship between TP and COD and Chl-a from this study could be used beneficially for water quality management of agricultural reservoirs and related water quality modeling.

• Journal of Biosystems Engineering
• /
• v.38 no.2
• /
• pp.129-137
• /
• 2013

Purpose: Modeling has been used for elucidating the mechanism of complex biosystems. In spite of importance and uniqueness of adolescent calcium (Ca) metabolism characterized by a threshold Ca intake, its regulatory mechanism has not been covered and even not proposed. Hence, this study aims at model-based proposing potential mechanisms regulating adolescent Ca metabolism. Methods: Two different hypothetic mechanisms were proposed. The main mechanism is conceived based on Ca-protein binding which induces renal Ca filtration, while additional mechanism assumed that active renal Ca re-absorption regulated Ca metabolism in adolescents. Mathematical models were developed to represent the proposed mechanism and simulated them whether they could produce adolescent Ca profiles in serum and urine. Results: Simulation showed that both mechanisms resulted in the unique behavior of Ca metabolism in adolescents. Based on the simulation insulin-like growth factor-1 (IGF-1) is suggested as a potential regulator because it is related to both growth, a remarkable characteristic of adolescence, and Ca metabolism including absorption and bone accretion. Then, descriptive modeling is employed to conceptualize the hypothesized mechanisms governing adolescent Ca metabolism. Conclusions: This study demonstrated that modeling is a powerful tool for elucidating an unknown mechanism by simulating potential regulatory mechanisms in adolescent Ca metabolism. It is expected that various analytic applications would be plausible in the study of biosystems, particularly with combination of experimental and modeling approaches.

• Clinical and Experimental Reproductive Medicine
• /
• v.48 no.4
• /
• pp.303-310
• /
• 2021

Decorin (DCN) is a proteoglycan belonging to the small leucine-rich proteoglycan family. It is composed of a protein core containing leucine repeats with a glycosaminoglycan chain consisting of either chondroitin sulfate or dermatan sulfate. DCN is a structural component of connective tissues that can bind to type I collagen. It plays a role in the assembly of the extracellular matrix (ECM), and it is related to fibrillogenesis. It can interact with fibronectin, thrombospondin, complement component C1, transforming growth factor (TGF), and epidermal growth factor receptor. Normal DCN expression regulates a wide range of cellular processes, including proliferation, migration, apoptosis, and autophagy, through interactions with various molecules. However, its aberrant expression is associated with oocyte maturation, oocyte quality, and poor extravillous trophoblast invasion of the uterus, which underlies the occurrence of preeclampsia and intrauterine growth restriction. Spatiotemporal hormonal control of successful pregnancy should regulate the concentration and activity of specific proteins such as proteoglycan participating in the ECM remodeling of trophoblastic and uterine cells in fetal membranes and uterus. At the human feto-maternal interface, TGF-β and DCN play crucial roles in the regulation of trophoblast invasion of the uterus. This review summarizes the role of the proteoglycan DCN as an important and multifunctional molecule in the physiological regulation of oocyte maturation and trophoblast migration. This review also shows that recombinant DCN proteins might be useful for substantiating diverse functions in both animal and in vitro models of oogenesis and implantation.

• Clinical and Experimental Pediatrics
• /
• v.53 no.7
• /
• pp.759-765
• /
• 2010

Purpose: This study evaluated the clinical manifestations of and risk factors for pituitary insufficiency in children and adolescents with Rathke's cleft cysts. Methods: Forty-four patients with Rathke's cleft cysts younger than 19 years who visited Seoul National University Children's Hospital between January 1995 and September 2009 were enrolled. Rathke's cleft cysts were confirmed histologically through an operation in 15 patients and by brain magnetic resonance imaging (MRI) in 29 patients. The clinical, hormonal, and imaging features were reviewed retrospectively. Results: The clinical presentation of symptomatic patients was as follows: headache (65%), endocrinopathy (61%), and visual disturbance (19%). Endocrinopathy included central precocious puberty (18%), diabetes insipidus (14%), general weakness (11%), and decreased growth velocity (7%). After surgery, hyperprolactinemia resolved in all patients, but growth hormone insufficiency, hypothyroidism, and diabetes insipidus did not improve. Pituitary insufficiency except gonadotropin abnormality correlated significantly with severe headache, visual disturbance, general weakness, and cystic size. Suprasellar extension of cysts and high signals in the T2-weighted image on brain MRI were related to hypothyroidism, hypocortisolism, and diabetes insipidus. Multivariable linear regression analysis showed that only general weakness was a risk factor for pituitary insufficiency ($R^2$=0.549). Conclusion: General weakness is a risk factor for pituitary insufficiency in patients with Rathke's cleft cysts. When a patient with a Rathke's cleft cyst complains of general weakness, the clinician should evaluate pituitary function and consider surgical treatment.

• Childhood Kidney Diseases
• /
• v.3 no.2
• /
• pp.109-116
• /
• 1999

Purpose: Insulin-like growth factor(IGF)-I and -II are peptide growth factor whose activity is modulated by interaction with the family of six IGF-binding proteins(IGFBPs). IGF-I is detected in rat kidney and has metabolic and growth effects. This study was designed to examine temporal expression of IGFBPs in kidney during renal development and postischemic regeneration in rat. Method: The expression of IGFBPs in kidney during renal development from 15th day of gestation to adult life by using Northern blot analysis. We also examined the renal IGF-IGFBP axis in uremic rat by using Northern blot and immunohistochemistry. Results: The mRNA of IGFBP-1 and -3 were not or barely detected in fetal stages. However, the mRNA level of IGFBP-1 and -3 were increased gradually from day 7 after birth to adult. In contrast, the mRNA of IGFBP-2 and -5 were highly expressed in fetal stages and maintained almost same levels until day 7 (IGFBP-2) or day 30 (IGFBP-5) after birth, then their levels decreased markedly. The mRNA of IGFBP-4 were expressed moderately in fetal kidney and increased gradually after birth. Interestingly, the mRNA of IGFBP-1 and-4 were induced up to 3-5 fold during maximum regeneration period and were recovered to normal levels after acute ischemic injury. In contrast, the mRNA level of IGFBP-3 and-IGFBPrP-1 were decreased slightly at 1 day after ischemic injury, then recovered to normal level during maximum regeneration period. Conclusion: There were differential expressions of IGFBPs in kidney that can modulate IGF action on developing, differentiating, maintaining, and regenerating renal structure and function.

• Asian-Australasian Journal of Animal Sciences
• /
• v.18 no.5
• /
• pp.716-722
• /
• 2005

Carcass weight and backfat thickness are primary yield grading factors. Insulin-like growth factor (IGF)-I/-II, transforming growth factor $\beta$1 (TGF-$\beta$1), and epidermal growth factor (EGF) regulate the proliferation and differentiation of cells including adipocytes. Also, interleukin (IL)-2/-6, cortisol, and dehydroepiandrosterone-sulfate (DHEA-S) are known to be related to muscle growth and fat depth. However, the relationships between endocrine factors and carcass grade have not been studied. Therefore, this study aimed to measure the concentrations of endocrine factors in serum and muscle, and to investigate the relationship of endocrine factors with carcass grade. A total of 60 crossbred gilts (Duroc${\times}$Yorkshire${\times}$Landrace) were used. Blood from the jugular vein was collected at antemortem (7 days before slaughter) and postmortem periods, and M. Longissimus was collected at 45 min and 24 h after slaughter. The concentrations of IGF-I/-II, EGF, TGF-$\beta$1, IL-2/-6, cortisol and DHEA-S were analyzed by radioimmunoassay (RIA) or enzyme-linked immunosorbent assay (ELISA). In general, IGF and EGF concentrations in serum and muscle of grade A carcasses were found to be higher than those of grade C carcasses at antemortem and postmortem periods, whereas the pattern of TGF-$\beta$1 concentration was reversed. In particular, the concentrations of muscle IGF-I (24 h postmortem) and serum TGF-$\beta$1 (antemortem) were significantly different between grades A and C (p<0.05). The present results indicate that serum and muscle growth factors affect carcass weight and backfat thickness, and indirectly suggest the possibility that carcass grade could be predicted by expression of serum and/or muscle growth factors.

• Korean Journal of Head & Neck Oncology
• /
• v.20 no.2
• /
• pp.128-134
• /
• 2004

Background and Objectives: Angiogenesis is the process of new blood vessel development from preexisting vessel. Angiogenenesis has been considered to be essential for the growth and expansion of a solid tumor. Vascular endothelial growth factor (VEGF), known as one of the most important vascular permeability factors, induces proliferation of endothelial cells, stiumulates angiogenesis, and increases vascular permeability. Several recents reports have documented that VEGF overexpression is associated with poor clinical outcomes in many maligmancies. The aims of this study were to determine whether microvessel density and VEGF expression are related to clinicopathologic factors such as age, sex, tumor size, tumor stage, and prognostic factors and to evaluate the relationship between VEGF expression and angiogenesis in benign and malignant thyroid tumors. Materials and Methods: The subjects were 65 patients (27 with papillary carcinoma, 27 with adenomatous hyperplasia, 11 with follicular adenoma) who underwent thyroidectomy from 1995 to 2001. Imuunohistochemistry was used to detect VEGF expression and microvessel density (MVD) in paraffin-embedded thryoid tumor specimens. Results: The intensity of the VEGF expression did not show stastically difference between benign and malignant thyroid tumors. There was no apparent correlation between VEGF expression and age, tumor size, T stage or scores of the AGES, AMES and MACIS systems. The neo-microvessel density was higher in the maligant tumor than the benign tumors. Also, higher neo-microvessel density was associated with metastases of the lymph nodes and scores of the AMES and AGES systems. Conclusion: Our results suggest that neo-microvessel vessel density may be a significant prognostic factor in the thyroid papillary carcinoma. But the VEGF expression does not appear to be an significant independent prognostic factor for thyroid papillary carcinoma.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.36 no.3
• /
• pp.145-157
• /
• 2020

Purpose: This study was to determine the possible effects of trichloroacetic acid (TCA) and epidermal growth factor (EGF) through cell survival genes of the PI3K-AKT signaling pathway when applying an hydrophobically modified glycol chitosan (HGC)-based nanocontrolled release system to human gingival fibroblasts in oral soft tissue regeneration. Materials and Methods: An HGC-based nano-controlled release system was produced, followed by the loading of TCA and EGF. The group was divided into control (CON), TCA-loaded nano-controlled release system (EXP1), and the TCA- and EGF- individually loaded nano-controlled release system (EXP2). A total for 29 genes related to the PI3K-AKT signaling pathway were analyzed after 48h of culture in human gingival fibroblasts. Real-time PCR, 1- way ANOVA and multiple regression analysis were performed. Results: Cell survival genes were significantly upregulated in EXP1 and EXP2. From multiple regression analysis, ITGB1 was determined to be the most influential factor for AKT1 expression. Conclusion: The application of TCA and EGF through the HGC-based nano-controlled release system can up-regulate the cell survival pathway.

• Korean Journal of Acupuncture
• /
• v.26 no.2
• /
• pp.27-38
• /
• 2009

Objectives: Rheumatoid arthritis (RA) is a chronic autoimmune disease, principally characterized by synovial inflammation of the joints. We previously reported the effect of acupuncture for RA, but the mechanism is still unclear. Various factors such as oxidative stress and angiogenesis were involved in the pathogenesis of RA, and recently, it has also been reported that cytokines also play a major role in RA. Thus, we investigated whether acupuncture could induce any changes in the levels of cytokines including vascular endothelial growth factor (VEGF), angiogenin and epidermal growth factor (EGF) as well as erythrocyte sedimentation rate (ESR), c-reactive protein (CRP), and rheumatoid factor (RF) in the sera of RA patients. Methods: The forty three patients who met the American College of Rheumatology (ACR) criteria for RA recruited. The acupuncture group (n=21) underwent 14 sessions of partially individualized acupuncture treatment for 6 weeks, and the control group had no treatment (n=13) over the same periods. We evaluated ESR, CRP and RF. In addition, to find out the mechanism of acupuncture, we assessed the changes of the cytokine activities using protein cytokine array in the sera of the patients. Results: Acupuncture significantly decreased the levels of ESR and CRP, but RF were not changed after 6-week acupuncture treatments. Moreover, acupuncture reduced the levels of VEGF, angiogenin and EGF in the sera of the patients. Interestingly, they were related with angiogenesis, which is an important process in the pathogenesis of RA. The levels of oncostatin, interleukin(IL)-$1{\alpha}$, IL-8, leptin, monocyte chemotactic protein-1, macrophage-derived chemokine, macrophage inflammatory proteins-1, platelet-derived growth factor BB and RANTES were not changed significantly. Conclusions: The effect of acupuncture for reliving RA symptoms can be partially explained by inhibition of angiogenesis factors in the sera of the RA patients.

• The Korean Journal of Physiology and Pharmacology
• /
• v.6 no.5
• /
• pp.275-279
• /
• 2002

Nerve growth factor (NGF) is an important autocrine growth factor and also a survival factor for keratinocytes. NGF may act in the hyperproliferative condition, psoriasis. Clinically, the combination of psoralen and UVA (PUVA) has been used in the treatment of a wide variety of cutaneous disorders, such as psoriasis and vitiligo. However, the precise therapeutic mechanism of PUVA on the dermatologic diseases remains unclear. The purpose of this study was to examine whether the expression of NGF in cultured keratinocytes is influenced by PUVA. Thus, normal human keratinocytes were isolated from neonatal foreskin, and the third to fifth-passaged cells were used in this study. The cells were exposed to various doses of UVA (30, 60, 120 $mJ/cm^2)$ after adding 8-methoxypsoralen (8-MOP) to examine the expression of NGF mRNA. The RNA and protein of the cells were extracted at various time points (1, 8, 24 hours) after UVA irradiation to examine the expression of NGF mRNA and production of NGF protein. In keratinocytes, there were no differences in the expression of NGF mRNA between the different doses of UVA irradiation, however, the expression of NGF mRNA in UVA and PUVA groups tended to increase as the time increased. The expression of NGF mRNA was the highest in PUVA group, followed by UVA group and the lowest in 8-MOP group. The expressions of NGF protein at 1 and 8 hours after UVA irradiation were lower in the PUVA group than in the other groups. This study showed that the expression level of NGF protein in keratinocytes was relatively lower in the PUVA groups than in the other groups, suggesting that the therapeutic mechanism of PUVA in psoriasis is related to the decrease of NGF protein.