마우스 각종 장기의 Xanthine Dehydrogenase-Xanthine Oxidase 활성도에 미치는 산소 농도의 영향

장승훈,한기정,권년수,이희성 중앙대학교 의과대학 의과학연구소 1993 中央醫大誌 Vol.18 No.2

Xanthine oxidase (XO) derved from xanthine dehydrogenase (XD) during ischemia plays important roles in tissue damage by generating superoxide radicals. In the present study, we examined in vivo regulations of XD-XO activities of various organs by environmental oxygen tension. Mice were exposed to 100% oxygen for 3, 10, or 30 h, or 7% oxygen (73% nitrogen) for 4h. XD-XO activities of liver, kidney, lung and brain were measured. The enzyme activities in both liver and kidney were markedly increased by the treatment with 100% oxygen. In the liver the enhanced activity was sustained until 30 h, while the elevated renal activity was found only in the mouse treated for 10 h. XD-XO activities were decreased in lung and brain by the treatment with 100% oxygen. When mice were exposed to 7% oxygen, XD-XO activity was markedly decreased in lung and brain, while the activites in liver and kidney were not significantly changed. These results indicate that XD-XO can be regulated by the environmental oxygen tension, and the regulation is organ-specific.

Effect of Plasma Power Strength on Optical Transitions in Silicon-nitride Films

장승훈,SungHoon Jung,최은집,한문섭,이주한 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.3

We synthesized the plasma power controlled silicon nitride (PPCSN) films by plasma-enhanced chemical vapor deposition (PECVD). We fixed the flow rate of SiH_4 (43 sccm) and N_2 (12.0 sccm) and varied the plasma power of reactant gas in the range of 20 W to 60 W. Using photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS) we investigate the luminescence origin of these films. As the plasma power increase, we recognize that the PL peak position shifts toward higher energy and the PL intensity becomes stronger. We also observe that all the PL spectra for the PPCSN films consist of three transitions which we denote A, B and I. Analyzing the Si 2p and N 1s XPS core-level spectra, we extract several components of different chemical states. Using the chemical state analysis, we discuss luminescence origin for each transition of A, B and I. We note that one component of Si 2p chemical states indicates the amount of silicon quantum dots (QDs) and other one is closely associated with increase of the PL intensity for the transition A. Also we interpret that the transition I arises from the interfacial region between Si QD and silicon nitride matrix. The transition B is related with some specific nanostructure of silicon nitride excluding the possibility of Si QDs.

만성 기침에서 스테로이드 반응 군 예측을 위한 설문지의 유용성

장승훈,엄광석,반준우,김동규,박용범,이재영,전만조,이명구,정기석 대한결핵 및 호흡기학회 2003 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.97 No.0

Long Term Therapeutic Plan for Patients with Non-Small Cell Lung Cancer Harboring EGFR Mutation

장승훈 대한결핵및호흡기학회 2014 Tuberculosis and Respiratory Diseases Vol.76 No.1

Non-small cell lung cancer harboring epidermal growth factor receptor (EGFR) sensitizing mutations has a distinct disease entity. Patients with this cancer have better prognosis, and frequently achieve long-term survival. EGFR-tyrosine kinase inhibitor (TKI) is the drug of choice for this cancer; but the disease inevitably progresses, after durable response. The tumor is a mixture of EGFR-TKI sensitive clones and resistant clones, regardless of their molecular mechanisms. EGFR-TKI sensitive clones are very susceptible to this drug, but rarely eradicated; so, withdrawal of the drug permits rapid regrowth of drug sensitive clones, possibly causing “disease flare.” Re-administration or continuation of EGFR-TKI can effectively suppress the expansion of drug sensitive clones, even when the total tumor volume continuously increases. Chemotherapy can definitely prolong the survival of patients experiencing EGFR-TKI failure. Prospective clinical trials are warranted to compare efficacies of chemotherapeutic agents. A few retrospective studies suggested that a taxane-based regimen may be superior to others. Here, we reviewed therapeutic options and clinical evidence about this unique disease entity.

임상강좌 : 폐 결절

장승훈 대한내과학회 2010 대한내과학회 추계학술대회 Vol.2010 No.-

혈청 TGF-β의 폐암 표지자로서의 역할

장승훈,유철규,김영환,한성구,심영수 대한결핵 및 호흡기학회 1996 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.83 No.0

폐암 검진 권고안

장승훈,신승수,김혜영,임현우,김재우,박인규,김영환,이계영,이경수,이종목,황보빈,백상현,김진환,성낙진,이상현,황승식,김수영,김열,이원철,성숙환,박보영 대한의사협회 2015 대한의사협회지 Vol.58 No.4

Lung cancer is the leading cause of cancer death in many countries, including Korea. The majority of patients are inoperable at the time of diagnosis because symptoms are typically manifested at an advanced stage. A recent large clinical trial demonstrated significant reduction in lung cancer mortality by using low dose computed tomography (LDCT) screening. A Korean multisociety collaborative committee systematically reviewed the evidences regarding the benefits and harms of lung cancer screening, and developed an evidence-based clinical guideline. There is highlevel evidence that annual screening with LDCT can reduce lung cancer mortality and all-cause mortality of high-risk individuals. The benefits of LDCT screening are modestly higher than the harms. Annual LDCT screening should be recommended to current smokers and ex-smokers (if less than 15 years have elapsed after smoking cessation) who are aged 55 to 74 years with 30 pack-years or more of smoking-history. LDCT can discover non-calcified lung nodules in 20 to 53% of the screened population, depending on the nodule positivity criteria. Individuals may undergo regular LDCT follow-up or invasive diagnostic procedures that lead to complications. Radiation-associated malignancies associated with repetitive LDCT, as well as overdiagnosis, should be considered the harms of screening. LDCT should be performed in qualified hospitals and interpreted by expert radiologists. Education and actions to stop smoking must be offered to current smokers. Chest radiograph, sputum cytology at regular intervals, and serum tumor markers should not be used as screening methods. These guidelines may be amended based on several large ongoing clinical trial results.

만성 기침에 대한 오해와 진실

장승훈 대한내과학회 2017 대한내과학회지 Vol.92 No.6

There seem to be several pitfalls in an anatomic, diagnostic protocol for the evaluation of chronic cough. Instead, it is reasonable to propose that non-asthmatic chronic cough depends on the combined effects of an underlying, abnormally enhanced cough reflex and aggravating factors. Unexplained chronic cough is distressingly common despite a systematic diagnostic approach. It is often related to bronchial hypersensitivity and nonspecific bronchial inflammation. Inhaled corticosteroid (ICS) is effective for asthmatic cough. ICS is less effective in non-asthmatic cough than in asthma but not ineffective. It can be modestly effective in a significant portion of patients with non-asthmatic cough. Cough itself can induce upper airway mucosal inflammation, which could enhance the cough reflex and viciously aggravate cough. Therefore, an antitussive agent is not a just symptom controller but can play a major role in successful cough control. Cough can be more effectively controlled by behavioral interventions, with psychological counseling in addition to a pharmacological approach. ICS and antihistamines can reduce cough regardless of its cause, so therapeutic diagnosis is a misconception in the diagnosis of cough.

다중 안테나 다중 사용자 환경에서 최대 성능에 근접하는 선형 precoding 기법

장승훈,김동구,양장훈,장규환 한국통신학회 2009 韓國通信學會論文誌 Vol.34 No.4

본 논문은 최적 전송률에 가까운 성능을 보이는 선형 precoding 기법을 제안한다. MMSE precoding은 ZF precoding 방식보다 우수한 평균 자승 오차 성능을 가진다. 반면 MMSE precoding 방식의 전송률은 낮은 SNR 범위에서는 ZF 방식에 비해 개선된 성능을 보여주지만 높은 SNR에서는 오히려 성능 열화현상을 보인다. 본 논문에서는 최적 전송률에 근접하는 선형 precoding 기법을 제안한다. 제안된 방식은 ZF precoding방식에서 사용되는 역행렬 연산을 전송율이 최대화될 수 있도록 정규화(regularization)하는 방식이고 이를 위한 간단한 수치 알고리즘이 제안된다. 또한 그 과정에서 낮은 복잡도를 가지는 간단한 전력 재할당에 의한 regularization 방식이 제안된다. 시뮬레이션과 성능분석을 통해 제안된 방식이 모든 SNR 범위에서 기존의 ZF precoding 방식과 MMSE precoding방식보다 높은 전송률을 가짐을 보인다. 또한 제안된 방식은 채널 추정 오차가 존재하는 경우에도 기존의 선형 precoding 방식과 비교하여 성능 이득을 유지하면서 채널 추정 오차에 강인함을 가진다.

폐암 정복을 위한 전방위적 반격

장승훈 대한의사협회 2023 대한의사협회지 Vol.66 No.3

Background: Lung cancer is increasing exponentially as the population ages. To conquer lung cancer, early diagnosis, developing new treatments, and combining multidisciplinary treatment modalities are essential. Current Concepts: Since the national lung cancer screening program for high-risk individuals using low-dose chest computed tomography has launched, the rate of early diagnosis of lung cancer is expected to increase. The development of immune checkpoint inhibitors and target agents is paying off in terms of producing new anticancer drugs. Immune checkpoint inhibitors are administered in combination with existing treatment modalities in various clinical situations, such as for not only patients with metastatic lung cancer but also for those with resectable lung cancer and with surgically unresectable locally advanced disease. These trials dramatically improved survival outcomes. The development of targeted anticancer drugs is also advancing at a rapid pace. The survival rate of patients with lung cancer who have specific gene mutations has greatly improved when targeted anticancer drugs are administered alone or in combination with conventional therapies. Discussion and Conclusion: Early diagnosis of lung cancer and the development of new treatment modalities are greatly improving the prognosis of patients with lung cancer. Attempts to combine conventional and new treatment modalities should continue. It is necessary to discuss changing medical policies for long-term survivors, which will inevitably increase.