Purification and Characterization of Helicobacter pylori ${\gamma}$-Glutamyltranspeptidase

Song, Jae-Young,Choi, Yeo-Jeong,Kim, Jeong-Min,Kim, Yoo-Ree,Jo, Jin-Seong,Park, Jin-Sik,Park, Hee-Jin,Song, Yun-Gyu,Lee, Kon-Ho,Kang, Hyung-Lyun,Baik, Seung-Chul,Youn, Hee-Shang,Cho, Myung-Je,Rhee, Kw The Korean Society for Microbiology 2011 Journal of Bacteriology and Virology Vol.41 No.4

Gamma-glutamyltranspeptidase (GGT) was purified to electrophoretic homogeneity from the cell extract of H. pylori. The purified enzyme consisted of heavy and light subunits with molecular weights of 38 kDa and 21 kDa, respectively. N-terminal amino acid sequence of heavy and light subunits revealed that H. pylori GGT was processed into 3 parts for a signal peptide of 27 amino acid residues, a heavy subunit of 352 residues, and a light subunit of 188 residues during translation. The reaction rate for hydrolysis of ${\gamma}$-GpNA was 84.4 ${\mu}mol/min$ per milligram of protein, and that for the ${\gamma}$-glutamyl transfer from ${\gamma}$-GpNA to gly-gly was 23.8 ${\mu}mol/min$ per milligram of protein. The apparent Km values of H. pylori GGT for ${\gamma}$-glutamyl compounds were on the order of $10^{-3}$ to $10^{-4}$ M and those for acceptor peptides and amino acids were on the order of $10^{-1}$ to $10^{-2}$ M. The GGT protein kept approximately 80% of the initial enzymatic activity on incubation at $60^{\circ}C$ for 15 min. The optimum temperature and pH for reactions of both hydrolysis and transpeptidation were $40^{\circ}C$ and 9.0, respectively. The transpeptidation and hydrolysis reactions catalyzed by H. pylori GGT were strongly inhibited by L-Gln and moderately inhibited by L-Ala, L-Ser, ${\beta}$-chloro-L-Ala, and L-Glu. These results demonstrated that the biochemical properties of H. pylori GGT are different from those of other bacterial GGTs. Further, H. pylori GGT might degrade glutathione in the gastric mucous layer of humans if the enzyme could be secreted in the bacterial niches.

SUPEROXIDE DISMUTASE 가 허혈 손상된 백서 근육 조직에 미치는 영향

민대홍,김승홍,백무현,김승한 大韓成形外科學會 1991 Archives of Plastic Surgery Vol.18 No.4

Superoxide radicals have been shown to play an important role in the cellular injury of reperfused ischemic tissue. We examined the protective effect of superoxide dismutase(SOD), one of the derivatives of superoxide rradical scavengers, on the reperfusion injury of replanted rat limb with 6 - hour is - chemic period. Biochemically, the amounts of superoxide radicals in ischemic hindlimbs treated with SOD have decreased significantly compared to those of control group.(p<0.01) Histologically, SOD treated extremities demonstrated less inflammatory reaction and degenerative change than control group. Our results indicate that the administration of SOD to a amputation part by means of intraarterial perfusion after prolonged period of warm ischemia significantly decreases the tissue damage.

가토에서 음각틀을 이용한 이개 재건의 실험적 연구

민대홍,김승홍,백무현,김원석 大韓成形外科學會 1991 Archives of Plastic Surgery Vol.18 No.4

The formation or reconstruction of an auricle is one of the most difficult operations in plastic and reconstructive facial surgery. The difficulties of its reconstruction include delicate structures of the ear, extremely thin skin, difficulty in color match, and springing effect of the thin supporting skeleton consists of cartilage with its peculiar recesses and bumps. Even though, several techniques have been using for auricular reconstruction, it would be difficult to obtain an ideal auricle. Furthermore surgeon's talent and sufficient practice might be needed for a satisfactory result. We attempted auricular reconstruction using negative auricular plastic mold in 10 white rabbits in order to pursue a simple and satisfactory method. Diced cartilage chips were filled into a subcutaneous pocket placed in the negative auricular mold. Mild negative pressure was maintained in the space between the cartilage-subcutaneous tissue-skin complex and mold for two months. The results were as follows: 1.An ideal shaped suitable supporting skeleton was newly formed and the fabricated new auricle had a near normal appearance. 2.Under the microscopic examination, the diced cartilage chips have conglomerated together to form a solid skin - connective tissue - cartilage framework and evenmore matured chondrocytes were noted.

열복사의 색수차 공간여과를 이용한 레이저 용접 감시기술

김민석,백성훈,박승규,정진만,김철중 한국레이저가공학회 1999 한국레이저가공학회지 Vol.2 No.2

An innovative real-time weld monitoring technique using chromatic filtering of the thermal radiation from a weld pool is developed. This thermal radiation from the weld pool is focused on an aperture and the transmitted thermal radiation is monitored at two wavelengths with high-speed single-element detectors. Due to the chromatic aberration introduced in the focusing optics, the transmittance curve of thermal radiation varies by the wavelength. Owing to this difference in the transmittance, the local variation of thermal radiation from the weld pool can be monitored by processing the two spectroscopic signals from two detectors. In this paper, the algorithms to monitor the laser power on the weld specimen and the focus shift are investigated and the performances of laser power and focus monitoring are shown for a pulsed Nd:YAG laser welding. The monitoring of the weld pool size variation is also discussed.

어류 성장에 있어서 식물 및 동물플랑크톤의 먹이기여도

김백호,김미연,최환석,김정중,최민규,박승택,정연태,高村典子 원광대학교 환경과학연구소 2000 環境科學硏究誌 Vol.9 No.1

압입유동특성 평가를 위한 진변형률 정의에 관한 고찰

전은채,백민경,김성훈,박주승,권동일 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.12

Continuous indentation test is getting more used to derive indentation flow curve. The overall deriving algorithm is relatively well-established, the details of the algorithm are, however, still argued. One of the arguments is the definition of true strain which constitutes the indentation flow curve. In this study, work-hardening exponent was adopted for determining what definition is appropriate to obtain accurate indentation flow curve since work-hardening exponent is affected by only the definition of true strain not by other constants. The effect of calibrating contact depth was eliminated using finite element analysis. Finally, the definition based on tangent function was determined to be proper for deriving the indentation flow curve. (Received September 8, 2004)

자발성 뇌교출혈 환자의 예후에 관한 임상 분석

조재영,석종식,민병국,권정택,최덕영,황성남,김영백,박승원 중앙대학교 의과대학 의과학연구소 2002 中央醫大誌 Vol.27 No.1

Patients with spontaneous pontine hemorrhage very often develop setvere disturbances of consciousness,pupilary abnormalities, respiratory and motor. They have high mortality rate. Therefore, I analyzed the correlation between the Glasgow outcome scale(GOS)and clincial manifestations or computed tomographic(CT)findings in 48 patients with spontaneous pontine hemorrhage to clarify factors predicting the prognosis. I examined 48 Patients with spontaneous pontine hemorrhage; 33 males and 15 females, age 54.6±8.99(mean±S.D.;range 39 to 68)brought to our hospital between January 1995 and December 1999, retrospectively. Correlations between the clinical manifestations, CT findings and the GOS was assessed with multivariate regression analysis. The results were as follow: 1) Patients with the pontine hemorrhage were of 8.8% in those with intracerebral hemorrhage. The ratio of male and female was 33 to 15. The incidence of age is eqial to 40,50 and 60. Total mortality was 41.6%. 2) The poor prognostic factor were that; Glasgow coma scale(GCS)3∼8, irregular respiration. pupilary abnormality, quadriplegia, Brain CT typeⅠ(massive), hydrocephalus, extrapontine extension, Intraventricular hemorrhage(IVH). These clinical analysis should be useful in determining the level of care and future resuscitative efforts.

익산시 주변 하천 담수조류군집의 다양성에 대하여

최환석,김미연,김백호,최민규,박승택 원광대학교 환경과학연구소 2000 環境科學硏究誌 Vol.9 No.1

Effect of spark plasma sintering conditions on the thermoelectric properties of (Bi_0.25Sb_0.75)₂Te₃ alloys

Lim, Sang-Soon,Kim, Ju-Heon,Kwon, Beomjin,Kim, Seong Keun,Park, Hyung-Ho,Lee, Ki-Suk,Baik, Jeong Min,Choi, Won Jun,Kim, Dong-Ik,Hyun, Dow-Bin,Kim, Jin-Sang,Baek, Seung-Hyub Elsevier 2016 JOURNAL OF ALLOYS AND COMPOUNDS Vol.678 No.-

<P><B>Abstract</B></P> <P>As a field-assisted technique, spark plasma sintering (SPS) enables densification of specimens in a very short period of time compared to other sintering techniques. For high performance thermoelectric material synthesis, SPS is widely used to fabricate nanograin-structured thermoelectric materials by rapidly densifying the nanopowders suppressing grain growth. However, the microstructural evolution behavior of thermoelectric materials by SPS, another important process during sintering, has been rarely studied. Here, we explore SPS as a tool to control the microstructure by long-time SPS. Using p-type (Bi<SUB>0.25</SUB>Sb<SUB>0.75</SUB>)<SUB>2</SUB>Te<SUB>3</SUB> thermoelectric materials as a model system, we systematically vary SPS temperature and time to understand the correlations between SPS conditions, microstructural evolution, and the thermoelectric properties. Our results show that the relatively low eutectic temperature (∼420 °C) and the existence of volatile tellurium (Te) are critical factors to determine both microstructure and thermoelectric property. In the liquid-phase sintering regime, rapid evaporation of Te leads to a strong dependence of thermoelectric property on SPS time. On the other hand, in the solid-phase sintering regime, there is a weak dependence on SPS time. The optimum thermoelectric figure-of-merit (Z) of 2.93 × 10<SUP>−3</SUP>/K is achieved by SPS at 500 °C for 30 min. Our results will provide an insight on the optimization of SPS conditions for materials containing volatile elements with low eutectic temperature.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Spark plasma sintering (SPS) is used to synthesize the thermoelectric (Bi<SUB>0.25</SUB>Sb<SUB>0.75</SUB>)<SUB>2</SUB>Te<SUB>3</SUB>. </LI> <LI> Liquid phase and volatile element are a key for the microstructure and thermoelectric property. </LI> <LI> Thermoelectric figure-of-merit of 2.9 × 10<SUP>−3</SUP>/K is achieved at 500 °C for 30 min. </LI> </UL> </P>

Weighing the benefits of lymphadenectomy in early-stage colorectal cancer

Seung Min Baik,Ryung-Ah Lee 대한외과학회 2023 Annals of Surgical Treatment and Research(ASRT) Vol.105 No.5

Recent advancements in endoscopic procedures have resulted in a growing diagnosis of early colorectal cancer (CRC) cases, where classical en bloc lymph node (LN) dissection is not performed and treatment is terminated with the removal of the main cancer lesion by endoscopy without pathologic LN staging. Although many studies report noninferior outcomes of endoscopic resection in comparison to surgical resection, a cautious approach to completing treatment with endoscopic resection alone is recommended because LN metastases may be present even in early-stage CRC. In most countries, including the United States, Europe, and South Korea, the guidelines for additional surgery after endoscopic resection are very similar. If LN metastasis is suspected, even in T1 stage or lower lesions, further surgery is an essential treatment modality, but confirmation of the presence of LN metastasis is perhaps the most difficult part of this process. Another paradoxical recent trend is the expansion of more extensive and complete surgical lymphadenectomy for CRC. The success rate of surgery has improved dramatically over the past decade with the introduction of surgical devices and minimally invasive surgery, and the associated risks have been significantly reduced. While the burden of surgery on patients is understandable, the indications for surgery in early colon cancer need to be carefully reviewed to improve cure rates. In this process, we believe that an integrated decision-making process with surgeons, radiologists, and pathologists, in addition to the opinions of endoscopists, will be an important process to improve the cure rate.