1,721,069 research outputs found
High-yield synthesis and purification of recombinant human GABA transaminase for high-throughput screening assays
No full text© 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.Many studies have focussed on modulating the activity of γ-aminobutyric acid transaminase (GABA-T), a GABA-catabolizing enzyme, for treating neurological diseases, such as epilepsy and drug addiction. Nevertheless, human GABA-T synthesis and purification have not been established. Thus, biochemical and drug design studies on GABA-T have been performed by using porcine GABA-T mostly and even bacterial GABA-T. Here we report an optimised protocol for overexpression of 6xHis-tagged human GABA-T in human cells followed by a two-step protein purification. Then, we established an optimised human GABA-T (0.5 U/mg) activity assay. Finally, we compared the difference between human and bacterial GABA-T in sensitivity to two irreversible GABA-T inhibitors, gabaculine and vigabatrin. Human GABA-T in homodimeric form showed 70-fold higher sensitivity to vigabatrin than bacterial GABA-T in multimeric form, indicating the importance of using human GABA-T. In summary, our newly developed protocol can be an important first step in developing more effective human GABA-T modulators.11Nsciescopu
The Effect of Calcium Phosphate Sealers on MG 63 Osteoblast–like Cell Behavior
No full text학위논문 (석사)-- 서울대학교 대학원 : 치의학과, 2012. 2. 손원준.In regard to biological properties of endodontic sealers, there are many characteristics that should be considered. The issue of tissue irritation and biocompatibility has long been raised for all types of sealers. The calcium phosphate based root canal sealers, which is currently under new development (new CPS group; CAPSEAL I, CAPSEAL II) already showed good canal sealing ability, physical properties and low inductivity of inflammatory mediators in human periodontal ligament cells. The aim of this study was to compare the biocompatibility of CAPSEAL group with other sealers in the periapical bony tissue and to investigate the biological effects of the calcium phosphate sealers on the periapical osseous healing process of endodontic lesion.
The biocompatibility of sealers was examined using cell viability assay (MTT) and the osteogenic potential of CAPSEAL group was analyzed by comparing the effects on the osteoblast differentiation of precursor cells. The MG63 human osteoblast-like cells were treated with sealers and the mRNA levels of the differentiation marker genes (alkaline phosphatase, osteonectin, osteopontin, osteocalcin) were detected by reverse transcription PCR (RT-PCR). CAPSEAL I, CAPSEAL II, another types of commercially available calcium phosphate sealers (Apatite Root Sealer type I [ARS I]and Apatite Root Sealer III [ARS III]; Sankin Kogyo, Tokyo, Japan) and a zinc oxide eugenol based sealers (Pulp Canal Sealer EWT [PCS EWT]; Kerr, Detroit, MI) were examined.
The results showed the cytotoxicity of CAPSEAL group was very low, and the mild cytotoxic effect of ARS I and III was observed in MG63 cells at 14days. RT-PCR analysis showed the early stage markers (alkaline phosphatase and osteopontin) were upregulated at 1, 3, and 7 days in CAPSEAL I, II, and ARS III and the effects were prominent at 7 days. The another early marker osteonectin was also upregulated at 1 day. The expression of the late stage marker osteocalcin was detected at 14 days when exposed to ARS I and CAPSEAL I.
In this study, CAPSEAL group showed more biocompatible results than ZOE-based sealer (EWT) and another types of available calcium phosphate sealers (ARS I and III) in MG63 osteoblast-like cells. Moreover, beyond the bioinert and biocompatible properties, CAPSEAL group were observed to facilitate the periapical osseous healing process of endodontic lesion. These findings suggest that the CAPSEAL I and II are promising useful root canal sealers.근관충전은 근관치료의 마지막 단계로서 근관충전 재료나 충전 술식에 관계없이 근관충전용 selaer가 치밀한 밀폐를 획득하기 위하여 반드시 필요하다. 충전 후 미세누출 실험을 통하여 sealer가 치근단조직과 접촉한다는 것이 알려졌으며 sealer의 생체적합성과 조직자극성은 중요하게 연구되어 왔다. 최근 새롭게 개발된 인산칼슘계 근관충전용 sealer (CAPSEAL I, CAPSEAL II)는 기존의 연구를 통하여 sealer로서의 적절한 물성과 우수한 근관밀폐능력이 확인되었으며 치주인대세포주에서 염증물질을 낮은 수준으로 유도하는 것이 보고되었다. 본 연구에서는 치근단 골성조직과 접촉한 CAPSEAL group을 포함한 sealer들의 조직 독성을 비교 분석하고, CAPSEAL group을 포함한 인산칼슘계 근관충전용 sealer가 치근단 병소의 골성 치유 과정에 기여할 수 있는가를 알아보고자 하였다.
먼저 골아세포의 전구세포로서 MG63 유사골아세포주를 대상으로 MTT assay를 시행하여 sealer의 세포독성을 비교하였다. 또한 치근단 병소의 골성치유과정에 대한 CAPSEAL group의 효과를 규명하고자 골아세포 분화과정에 sealer가 미치는 영향을 살펴보았다. 배양된 MG63 유사골아세포에 sealer를 처리한 후 각각 1, 3, 7, 14일 후 골아세포 분화의 지표들 (alkaline phosphatase, osteonectin, osteopontin, osteocalcin)의 발현 수준을 역전사 PCR를 실시하여 확인하였다. 모든 실험은 CAPSEAL I, II 및 기존의 인산칼슘계 근관충전용 sealer(ARS I, III)와 ZOE계열 sealer(EWT)에서 이루어졌으며 비교분석을 통하여 새로운 인산칼슘계 근관충전용 sealer의 생물학적 효과를 규명하였다.
MTT 분석 결과, CAPSEAL group은 MG63 유사골아세포에서 가장 낮은 세포독성을 보였다. ZOE계열 EWT selaer는 높은 세포 독성을 보여 18시간 후부터 급격한 세포 독성이 관찰되었으며 ARS I, III의 경우 약한 수준의 독성을 보여 14일 경과 후에 그 효과가 관찰되었다. 역전사 PCR 결과, CAPSEAL I, II 및 ARS III group에서 골아세포의 분화에 관련된 유전자들의 mRNA 발현 수준이 높게 측정되었다. 골아세포 분화의 초기 지표로 알려진 alkaline phosphatase가 1, 3, 7일 후에 높은 수준으로 나타났으며 또 다른 초기 지표인 osteonectin의 수준도 위의 세 group에서 1일 후 증가되었고, osteopontin mRNA의 수준도 1, 3, 7일 후에 높은 수준을 보였다. Alkaline phosphatase와 osteopontin의 두드러진 발현 증가는 7일 후의 결과에서 뚜렷하게 관찰되었다. 후기 지표로 알려진 osteocalcin는 CAPSEAL I, ARS I sealer 처리군에서 14일 후 높은 수준으로 확인되었다.
이러한 결과로부터 새롭게 개발된 인산칼슘계 근관충전용 sealer인 CAPSEAL group이 MG63 유사골아세포에서 우수한 생체적합성을 가질 뿐만 아니라, 치근단공을 통하여 유출된 sealer가 골아세포 전구세포의 분화과정에 기여함으로써 치근단 병소의 골성 치유에 작용할 수 있는 가능성을 확인하였다.Maste
Structural insights into the clustering and activation of Tie2 receptor mediated by Tie2 agonistic antibody
No full text© 2021, The Author(s).Angiopoietin (Angpt)-Tie receptor 2 (Tie2) plays key roles in vascular development and homeostasis as well as pathological vascular remodeling. Therefore, Tie2-agonistic antibody and engineered Angpt1 variants have been developed as potential therapeutics for ischemic and inflammatory vascular diseases. However, their underlying mechanisms for Tie2 clustering and activation remain elusive and the poor manufacturability and stability of Angpt1 variants limit their clinical application. Here, we develop a human Tie2-agonistic antibody (hTAAB), which targets the membrane proximal fibronectin type III domain of Tie2 distinct from the Angpt-binding site. Our Tie2/hTAAB complex structures reveal that hTAAB tethers the preformed Tie2 homodimers into polygonal assemblies through specific binding to Tie2 Fn3 domain. Notably, the polygonal Tie2 clustering induced by hTAAB is critical for Tie2 activation and are resistant to antagonism by Angpt2. Our results provide insight into the molecular mechanism of Tie2 clustering and activation mediated by hTAAB, and the structure-based humanization of hTAAB creates a potential clinical application.11Nsciescopu
Identification and PEP Inhibitory Activity of Acetophenone Glucosides from the Clove Buds (Syzygium aromaticum)
No full textLatrophilin-2 is a novel receptor of LRG1 that rescues vascular and neurological abnormalities and restores diabetic erectile function
No full textDiabetes: Restoring erectile function lost to diabetes A protein that initiates multiple tissue repair processes could offer effective treatment for erectile dysfunction arising from diabetes mellitus. High blood sugar levels can lead to serious damage to nerves and blood vessels, with impaired male sexual function one potential consequence. Guo Nan Yinof the Inha University School of Medicine, Incheon, South Korea, and colleagues have identified a molecular pathway that can be targeted to reverse such damage. They determined that a protein called LRG1 acts on a receptor called LPHN2 to stimulate blood vessel and nerve growth. LPHN2 is highly expressed in the penile tissue of diabetic humans and rodents, and direct injection of LRG1 effectively restored erectile function in mice. The authors hypothesize that this same pathway could also be used for treatments for other diabetic complications, such as chronic wounds. Diabetes mellitus (DM) is a chronic metabolic disorder characterized by inappropriate hyperglycemia, which causes endothelial dysfunction and peripheral neuropathy, ultimately leading to multiple complications. One prevalent complication is diabetic erectile dysfunction (ED), which is more severe and more resistant to treatment than nondiabetic ED. The serum glycoprotein leucine-rich alpha-2-glycoprotein 1 (LRG1) is a modulator of TGF-beta-mediated angiogenesis and has been proposed as a biomarker for a variety of diseases, including DM. Here, we found that the adhesion GPCR latrophilin-2 (LPHN2) is a TGF-beta-independent receptor of LRG1. By interacting with LPHN2, LRG1 promotes both angiogenic and neurotrophic processes in mouse tissue explants under hyperglycemic conditions. Preclinical studies in a diabetic ED mouse model showed that LRG1 administration into the penile tissue, which exhibits significantly increased LPHN2 expression, fully restores erectile function by rescuing vascular and neurological abnormalities. Further investigations revealed that PI3K, AKT, and NF-kappa B p65 constitute the key intracellular signaling pathway of the LRG1/LPHN2 axis, providing important mechanistic insights into LRG1-mediated angiogenesis and nerve regeneration in DM. Our findings suggest that LRG1 can be a potential new therapeutic option for treating aberrant peripheral blood vessels and neuropathy associated with diabetic complications, such as diabetic ED.11Nsciescopuskc
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Application for Furniture Arrangement based on Virtual Reality to Share Interior Design in Real-time
No full textVariations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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