• Journal of Life Science
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• v.27 no.5
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• pp.584-590
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• 2017

Antifreeze proteins (AFPs) bind to ice crystals and inhibit their growth. AFPs are essential for the survival of organisms living in subzero environments. Type I AFP (AFP37) isolated from winter flounder is an ${\alpha}$-helical peptide of 37 residues long. In this study, we attempted to develop short AFP fragments with higher activity and solubility. We designed and synthesized N-terminal 15 and 21 residue-long AFPs, designated AFP15 and 21. Also dimerized AFP15 and 21, designated dAFP15N and dAFP21N, respectively, were generated through disulfide bonds between peptides containing CGG residues added to the N-terminus of AFP15 and AFP21 (designated AFP15N and 21N). Their helical contents and antifreeze activities were assessed using circular dichroism (CD) spectroscopy and a nanoliter osmometer, respectively. The helical content of AFP15 AFP21, AFP15N, AFP21N, dAFP15N and dAFP21N was 47, 48, 23.8, 28, 49.1, and 52%, respectively compared to that of wild type AFP37; the antifreeze activity was 8.4, 9.3, 0.05, 5.6, 12.1, 11.2% respectively, compared to that of wild type AFP37. Contrary to our anticipation, the dimerized peptides showed almost the same antifreeze activity as their monomeric counterparts. These results indicate that the dimerized peptides behave as monomeric peptides due to the high rotational freedom of disulfide bonds connecting two monomeric peptides. The star-shaped ice crystals generated by the peptides also demonstrated weak interaction between ice and peptides.

• The Korean Journal of Zoology
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• v.38 no.3
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• pp.382-387
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• 1995

To check the possible application of our anti-AFP monocional antibodies (MAbs) as immunodiagnostic reagents for hepatocellular carcinoma, ELISA and immunohistochemical assay were performed on the sera and liver biopsy specimens from the patients of hepatocellular carcinoma and other non-malignant hepatic disease. By non-competitive ELISA using anti-AFP MAbs, the highest incidence of AFP value was found only in the sera of hepatocellular carcinoma patients, i.e., more than 54% of patients had serum AFP levels of more than 500 ng/mi. By immunoperoxidase and indirect immunofluorescence techniques, anti-AFP MAbs were found to react with cytoplasm of hepatoceliular carcinoma cells. However immunohistochemical reactIvity to AFP in hepatocellular carcinoma cells was lower than that in non-neoplastic liver cells adjacent to the hepatocellular carcinoma. From these results with the similar findings from other studies, we suggest that AFP antigen is appropriate in the diagnosis assay (ELISA) but is not by immunohistochemical detection.

• Biomedical Science Letters
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• v.3 no.2
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• pp.115-123
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• 1997

$\alpha$-Fetoprotein (AFP) has been a useful marker in screening and/or monitoring patients with hepatocellular carcinoma, gonadal germ cell tumor, gastric carcinoma and neural tube defects. In the present study, it was attempted to produce anti-human AFP polyclonal antibodies and to develop a competitive enzyme-linked immunosorbent assay (ELISA) for the measurement of AFP in human plasma and amniotic fluid. AFP was isolated from amniotic fluid using an isolation procedure consisting of affinity chromatography and preparative polyacrylamide gel electrophoresis. The antibody directed against AFP was raised in rabbits. Double immunodiffusion and Western blotting methods showed that the antiserum was highly specific, reacting with only AFP-containing samples. Standard curve was obtained by using purified AFP and specific antiserum. The assay sensitivity was 5ng/ml and the working range was 5~l,000ng/ml. The within-assay and between-assay coefficient of variance (CV) was 4.5% and 8.5%, respectively. These results indicate that the assay is valuable for the measurement of AFP and found to be simple, reproducible, and accurate.

• The Korean Journal of Zoology
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• v.32 no.4
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• pp.314-321
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• 1989

배의 발생과 분화에 따른 혈청 alpha-fetoprotein (AFP)의 생리적 기능 규명을 위한 기초실험의 일환으로, 모체와는 완전히 독립된 상태에서 발생과 분화가 이루어지는 계배의 혈청을 재료로 하여 CM-Sephadex C-50, hydroxyapatite 및 DEAE-Sepharose A-25등의 크로마토그라피 방법에 의해 닭 혈청 AFP를 분리하였다. 계 AFP는 분자량이 약 60 Kd로 사람 및 다른 포유동물 AFP의 분자량 (64-74 Kd)보다 작았다. 닭 AFP, 계배혈청 및 닭 혈청 등을 토끼에 면역하여 항체를 제조하였고, 이를 이용하여 닭의 배발생 단계에 따른 혈청 AFP 함량의 변화를 전기영동 및 면역학적 방법으로 정성 및 정량 분석을 실시하였다. 혈청 AFP 함량은 발생 7일-배 (AFP 농도 : 0.81 mg/ml)부터 점차 증가하여 13일-배에서 최고치인 2.46 mgfml로 나타났으며 그 이후 급격히 감소되어 부화 직후에는 매우 낮은 농도 (0.22mg/ml)였고 부화 4일에 거의 없어 졌으며, 이와 같은 AFP 함량의 변화는 혈청 알부민 함량의 변화와 거의 반비례 함을 알았다. For the preliminary step to investigate the site of AFP synthesis, the ontogenic characteristics and the physiological function of AFP, alpha-fetoprotein was isolated from chick embryo serum through the procedures of CM-Sephadex C-50, hvdroxvapatite and DEAE-Sephadex A-50 chro-matography. The isolated AFP was proved to be pure and its molecular weight was found to be about 60 Kd. With this purified AFP, rabbit anti-chick hor was produced. The serum AFP level in chick embryo has been investagated by using polyacrylamide gel electrophoresis, immunoelec-trophoresis and single radial immunodiffusion from 7 days of incubation until 4 days after hatch-ing. It was found that the AFP level is increased from 0.81 mg/ml at daw-7 embryo to maximum value of 2.46 mg/ml at day-13 embryo, followed by rapid decreases until hatching.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.4
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• pp.1539-1544
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• 2014

Purpose: Alpha-fetoprotein (AFP), Lens culinaris agglutinin-reactive fraction of AFP (AFP-L3), and Golgi protein 73 (GP73) levels have been widely used as tumor markers for the diagnosis of hepatocellular carcinoma (HCC). The aim of this study was to investigate whether these tumor markers could be used to monitor short-term treatment response and recurrence of HCC in patients undergoing radiofrequency ablation (RFA). Methods: Between July 2012 and July 2013, 53 consecutive patients with newly diagnosed HCC were prospectively enrolled in this study. Among these, 32 patients underwent RFA, after which they were followed up prospectively at the First Hospital of Jilin University in China. Results: AFP, AFP-L3, and GP-73 values pre-RFA were not associated with tumor size, whereas AFP and GP-73 levels tended to be associated with tumor number, the presence of vascular invasion, deterioration of liver function, advanced-stage disease, and a poor performance status. GP-73 levels were dramatically elevated in the patients with hepatitis C-associated HCC. Neither pre-RFA nor 1-month post-RFA tumor marker values were associated with short-term outcome. The short-term recurrence rate of AFP-positive patients measured 1 month post-RFA was obviously higher than that of AFP-negative patients. Conclusions: AFP and GP-73 values were associated with clinical variables representing tumor growth and invasiveness, and the AFP value measured 1 month post-RFA was a strong predictor of short-term recurrence in patients with HCC.

• BMB Reports
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• v.53 no.8
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• pp.431-436
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• 2020

Alpha-fetoprotein (AFP) is one of the most commonly used and reliable biomarkers for Hepatocellular carcinoma（HCC). However, the underlying mechanism of AFP expression in HCC is poorly understood. In this study, we found that TCP10L, a gene specifically expressed in the liver, is down-regulated in HCC and that its expression inversely correlates with AFP expression. Moreover, overexpression of TCP10L suppresses AFP expression whereas knockdown of TCP10L increases AFP expression, suggesting that TCP10L might be a negative regulator of AFP. We found that TCP10L is associated with the AFP promoter and inhibits AFP promoter-driven transcriptional activity. Taken together, these results indicate that TCP10L negatively regulates AFP expression in HCC and that it could be a potential prognostic marker and therapeutic target for HCC.

• The Journal of the Korean life insurance medical association
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• v.17
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• pp.77-83
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• 1998

당사에서는 악성 종양에 대한 위험선택의 수단으로써 1997년 1월부터 종양표식자 중 CEA와 AFP 검사를 사의 진단에 한하여 실시하고 있다. 검사의 실시조건은 의사의 진찰소견으로 필요하다고 인정되는 경우와 관련병력의 고지가 있는 경우로 한하였다. 1997년 1월부터 10월말까지 실시한 건에 대해서만 분석을 하였으며 CEA 534건, AFP 608건를 실시하였다. 그 결과 기준치를 초과하는 경우는 CEA 33건, AFP 23건이었다. 표준체로 판정된 경우의 CEA의 평균치는 1.5ng/ml, AFP는 2.6ng/ml였다. CEA와 AFP의 검사결과나 그 이외의 원인으로 사절체의 판정을 받은 경우의 CEA의 평균치는 3.2ng/ml AFP의 경우는 20.7ng/ml로 나타났다. 본연구에서는 생명보험회사에서 종양표식자 검사의 의미를 검토해 보고자 하였다.

• The Korean Journal of Zoology
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• v.29 no.4
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• pp.283-293
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• 1986

For the preliminary step to make and characterize the monoclonal antibodies of human alpha-fetoprotein (AFP) was purified from 534g of human fetal tissues through the procedures of tissue extraction, DEAE-cellulose, concanavalin A-Sepharose, Cibacron Blue F3GA-agarose and immunoadsorbent affinity chromatography. The isolated AFP preparation showed a single band on polyacrylamide gel electrophoresis and a single precipitin are against rabbit anti-human cord serum and anti-human AFP on immunoelectrophoresis. Our AFP also displayed a single band on SDS-polyacrylamide gel electrophoresis. The recovery of AFP was 8.76mg total.

• Journal of Gastric Cancer
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• v.11 no.1
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• pp.23-30
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• 2011

Purpose: ${\alpha}$-fetoprotein (AFP)-producing gastric cancer is a rare tumor with high rates of liver metastasis and a poor prognosis. Many studies have been performed but there have been no comprehensive investigations of the clinicopathological and prognosis. Materials and Methods: Six hundred ninety four patients with gastric cancer who underwent a curative gastric resection in Hanyang University Hospital from February 2001 to December 2008 were evaluated retrospectively after excluding active or chronic hepatits, liver cirrhosis and preoperative distant metastasis. Among them, thirty five patients had an elevated serum level of AFP (>7 ng/ml) preoperatively. The clinicopathological features of AFP-producing gastric cancer were analyzed. Results: There was poorer differentiation, a higher incidence of lymph node metastasis, more marked lymphatic and vascular invasion in the AFP-positive group than in the AFP-negative group. The 5-year survival rate of the AFP-positive group was significantly poorer than that in the AFP-negative group (66% vs. 80%, P=0.002). A significantly higher incidence of liver metastasis was observed in the AFP-positive group than in the AFP-negative group (14.3% vs. 3.6%, P=0.002) with a shorter median time period from the operation to the metachronous liver metastasis (3.7 months vs. 14.1 months, P=0.043). Multivariate survival analysis revealed the depth of invasion, degree of lymph node metastasis and AFP-positivity to be the independent prognostic factors. Conclusions: AFP-producing gastric cancers have an aggressive behavior with a high metastatic potential to the liver. In addition, their clinicopathological features are quite different from the more common AFP-negative gastric cancer.

• Fisheries and Aquatic Sciences
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• v.19 no.8
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• pp.33.1-33.7
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• 2016

Antifreeze proteins (AFPs) lower the freezing point but not the melting point of aqueous solutions by inhibiting the growth of ice crystals via an adsorption-inhibition mechanism. However, the function of type IV AFP (AFP IV) is questionable, as its antifreeze activity is on the verge of detectable limits, its physiological concentration in adult fish blood is too low to function as a biological antifreeze, and its homologues are present even in fish from tropic oceans as well as freshwater. Therefore, we speculated that AFP IV may have gained antifreeze activity not by selective pressure but by chance. To test this hypothesis, we cloned, expressed, and assayed AFP IV from cultured subtropical olive flounder (Paralichthys olivaceus), which do not require antifreeze protein for survival. Among the identified expressed sequence tags of the flounder liver sample, a 5'-deleted complementary DNA (cDNA) sequence similar to the afp4 gene of the longhorn sculpin was identified, and its full-length cDNA and genome structure were examined. The deduced amino acid sequence of flounder AFP IV shared 55, 53, 52, and 49 % identity with those of Pleuragramma antarcticum, Myoxocephalus octodecemspinosus, Myoxocephalus scorpius, and Notothenia coriiceps, respectively. Furthermore, the genomic structure of this gene was conserved with those of other known AFP IVs. Notably, the recombinant AFP IV showed a weak but distinct thermal hysteresis of $0.07{\pm}0.01^{\circ}C$ at the concentration of 0.5 mg/mL, and ice crystals in an AFP IV solution grew star-shaped, which are very similar to those obtained from other polar AFP IVs. Taken together, our results do not support the hypothesis of evolution of AFP IV by selective pressure, suggesting that the antifreeze activity of AFP IV may have been gained by chance.