• Journal of Korean Neurosurgical Society
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• 제37권4호
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• pp.287-292
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• 2005

Objective: Recent clinical studies have demonstrated that intracisternal administration of recombinant tissue plasminogen activator(rt-PA) can facilitate the normal clearing of blood from the subarachnoid space. Urokinase, a first generation fibrinolytic agent, has been used to liquify such clots with some success. Therefore, recombinant tissue plasminogen activator, a second generation fibrinolytic drug that may be safer and more effective, is studied to evaluate its dosage to lyse clots in vitro and reactivity in the brain parenchyme. Methods: Intracerebral hematomas were created by stereotactically injecting 2ml of clotted autogenous blood into the brain parenchyme of total 28 anesthetized adult cats (weighting 3.8 to 4.1 kg). The control animals (group A) received 1 ml of normal saline injected into the clots and the experimental animals received each 0.1 mg of rt-PA (group B), 0.5mg of rt-PA (group C) and 1 mg of rt-PA (group D) at 6 hours after the clot injection. Results: 1. The amount of remained clots after lysing the hematomas were as follows: $1.80{\pm}0.17ml$ in group A, $1.65{\pm}0.23ml$ in group B, $0.61{\pm}0.37ml$ in group C and $0.52{\pm}0.34$ in group D. The result indicated that hematomas in rt-PA treated groups (C & D) were lysed better than the control group. 2. At least 0.5mg of rt-PA should be required for the lysis of 2ml of hematomas. 3. Light microscopic examination revealed no histological evidence of hemorrhage in tissue sections from each brain. Conclusion: Recombinant tissue plasminogen activator may be safely and effectively employed for the lysis of intracerebral hematomas in animal model.

• Bulletin of the Korean Chemical Society
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• 제31권9호
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• pp.2607-2612
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• 2010

Human tissue-type plasminogen activator (tPA) is a valuable thrombolytic agent used to successfully treat acute myocardial infarction, thromboembolic stroke, peripheral arterial occlusion, and venous thromboembolism. Recombinant tPA is accumulated as an inactive form in inclusion bodies of E. coli and is refolded in vitro, which is accompanied by extensive aggregation. In the present study, a tPA protease domain was expressed in an active soluble form in the cytosol of E. coli Rosetta-gami cells, which allowed disulfide bond formation and supplied the tRNA molecules required for six rarely used codons in E. coli. This strategy increased the amount of soluble protease domain protein and avoided the cumbersome refolding process. The purified protease domain not only degraded tPA substrate peptides but also formed a covalently bound complex with plasminogen activator inhibitor-1, as does full-length tPA. Soluble expression and purification of tPA domains may aid in functional analyses of this multi-domain protein, which has been implicated in many physiological and pathological processes.

• Journal of Microbiology and Biotechnology
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• 제23권8호
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• pp.1116-1122
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• 2013

Cell line development is the most critical and also the most time-consuming step in the production of recombinant therapeutic proteins. In this regard, a variety of vector and cell engineering strategies have been developed for generating high-producing mammalian cells; however, the cell line engineering approach seems to show various results on different recombinant protein producer cells. In order to improve the secretory capacity of a recombinant tissue plasminogen activator (t-PA)-producing Chinese hamster ovary (CHO) cell line, we developed cell line engineering approaches based on the ceramide transfer protein (CERT) and X-box binding protein 1 (XBP1) genes. For this purpose, CERT S132A, a mutant form of CERT that is resistant to phosphorylation, and XBP1s were overexpressed in a recombinant t-PA-producing CHO cell line. Overexpression of CERT S132A increased the specific productivity of t-PA-producing CHO cells up to 35%. In contrast, the heterologous expression of XBP1s did not affect the t-PA expression rate. Our results suggest that CERT-S132A-based secretion engineering could be an effective strategy for enhancing recombinant t-PA production in CHO cells.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.604-605
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• 2005

• 한국임상수의학회지
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• 제33권3호
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• pp.155-159
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• 2016

Four dogs were brought to the Veterinary Medicine Teaching Hospital of Seoul National University (VMTH SNU) with a history of hind limb ataxia, three with pain, one without pain. Three of the four showed weak to absent femoral pulses and cold extremities. Thromboembolism was identified by ultrasonography in the external and/or internal iliac arteries. A thrombolytic agent, recombinant tissue plasminogen activator (rt-PA), was administered (0.5-1 mg/kg, every 60-120 min, 3-5 doses). Two dogs (Cases 2 and 3), which were instantly provided rt-PA treatment, survived 6 and 17 months, respectively, although hematemesis and hematochezia were observed during treatment. In the other two dogs (Cases 1 and 4), rt-PA was administered 4 and 28 days after the appearance of pelvic limb symptoms, which may have limited the benefits of the treatment. When rt-PA treatment is instituted instantly and the side effects are monitored thoroughly during treatment, a good prognosis might be expected in canine aortic thromboembolism. For this reason, we suggest that rt-PA treatment should be initiated immediately if thromboembolism is identified.

• 한국임상수의학회지
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• 제34권4호
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• pp.275-278
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• 2017

An 8-year old female Korean Short Hair cat with a history of paralysis of both hind limbs less than 1 hour before admission was referred. On physical examination, the left hind limb was cold and there was no pulsation or mobility. On abdominal ultrasound examination, a thrombus 8 mm in length was found at the aortic bifurcation. The patient was diagnosed with hypertrophic cardiomyopathy (HCM) and cardiogenic pulmonary edema through radiologic evaluation and echocardiography. A tissue plasminogen activator (tPA) was applied intravenously using an accelerated dosing protocol (1 mg administered intravenously [IV] bolus, 2.5 mg IV over 30 min, 1.5 mg IV over 1 h) to treat the feline arterial thromboembolism. Within 12 h after administration of tPA, pulsation and mobility of both hind limbs were normal, without any noticeable complications. Clopidogrel was prescribed to prevent additional thrombus formation, and pimobendan, benazepril, and furosemide were prescribed for administration at home. The patient was discharged and survived 377 days.

• Journal of Microbiology and Biotechnology
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• 제21권12호
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• pp.1299-1305
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• 2011

An important modification of thrombolytic agents is resistance to plasminogen activator inhibitor-1 (PAI-1). In previous studies, a new truncated PAI-1-resistant variant was developed based on deletion of the first three domains in t-PA and the substitution of KHRR 128-131 amino acids with AAAA in the truncated t-PA. The novel variant expressed in a static culture system of Chinese Hamster Ovary (CHO) DG44 cells exhibited a higher resistance to PAI-1 when compared with the full-length commercial drug; Actylase. In the present study, the truncated-mutant protein was expressed in CHO DG44 cells in 50 ml orbital shaking bioreactors. The final yield of the truncated-mutant in the culture was 752 IU/ml, representing a 63% increase compared with the static culture system. Therefore, these results suggest that using the combined features of a transient and stable expression system is feasible for the production of novel recombinant proteins in the quantities needed for preclinical studies.

• 한국미생물·생명공학회지
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• 제16권6호
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• pp.522-525
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• 1988

무혈청 배지에 생산촉진제로 30$\mu$g/m$\ell$의 Heparin 을 첨가해 정상인의 섬유 세포로부터 상업적으로 tPA를 생산할 수 있는 방법의 개발과, 효과적인 tPA 생산을 위해 대량 배양에 적합한 무혈청 배지의 조성을 확립했다. 이 방법으로 연속배양 공법하에서 매일 1.1gram의 tPA가 생산될 수 있으며, 이 생산성은 tPA 생산 단가를 크게 낮출 분만 아니라 무혈청 배지의 사용으로 tPA의 순수 정제 과정을 크게 단축시킬 수 있다. 또한 이 세포에서 생산되는 tPA 는 fibrin lysis 시험결과 섬유질 분해능력이 높음이 입증되었으며, ELISA결과와도 상충했다.

• Journal of Microbiology and Biotechnology
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• 제16권5호
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• pp.695-703
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• 2006

The dissolved oxygen level of any cell culture environment has a critical effect on cellular metabolism. Specifically, hypoxia condition decreases cell viability and recombinant protein productivity. In this work, to develop CHO cells producing recombinant protein with high productivity, mammalian expression vectors containing a human tissue-type plasminogen activator (t-PA) gene with hypoxia response element (HRE) were constructed and stably transfected into CHO cells. CHO/2HRE-t-PA cells produced 2-folds higher recombinant t-PA production than CHO/t-PA cells in a $Ba^{2+}-alginate$ immobilized culture, and 16.8-folds in a repeated batch culture. In a non-aerated batch culture of suspension-adapted cells, t-PA productivity of CHO/2HRE/t-PA cells was 4.2-folds higher than that of CHO/t-PA cells. Our results indicate that HRE is a useful tool for the enhancement of protein productivity in mammalian cell cultures.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.257-260
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• 2002

Dissolved oxygen level of cell culture media has a critical effect on cellular metabolism, which governs specific productivity of recombinant proteins and mammalian cell growth However, in the cores of cell aggregates or cell-immobilized beads, oxygen level frequently goes below a critical level. Mammalian cells have a number of genes induced in the lower level of oxygen, and the genes contain a common cis-acting element (-RCGTG-), hypoxia response element (HRE). By binding of hypoxia inducible factor-l (HIF-I) to the HRE, promoters of hypoxia inducible genes are activated, which is a survival mechanism. In this work, to develop a CHO cell capable of producing recombinant proteins in immobilization and high density cell culture efficiently, mammalian expression vectors containing human tissue-type plasminogen activator (t-PA) gene controlled by HRE were constructed and stably transfected into the CHO cells. In $Ba^{2+}$ -alginate immobilization culture, CHO/pCl/dhfr/2HRE-t-PA cells produced 2 folds higher recombinant t-PA activity than CHO/pCl/dhfrlt-PA cells without $CoCl_2$ treatment. Furthermore, in repeated fed batch culture, productivity of t-PA in immobilized CHO/pCI/dhfr/2HRE-t-PA cells was 121 ng/ml/day, total production of 0.968 mg/day at 11 days culture while CHO/pCIIdhfrlt-PA cells was 22.8 ng/ml/day. All these results indicate that HRE is very useful for the enhancement of protein productivity in mammalian cell cultures.