• Nuclear Medicine and Molecular Imaging
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• v.41 no.2
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• pp.172-180
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• 2007

Among the nuclear medicine imaging methods available today, $H_2^{15}O-PET$ is most widely used by cognitive neuroscientists to examine regional brain function via the measurement of regional cerebral blood flow (rCBF). The short half-life of the radioactively labeled probe, $^{15}O$, often allows repeated measures from the same subjects in many different task conditions. $H_2^{15}O-$ PET, however, has technical limitations relative to other methods of functional neuroimaging, e.g., fMRI, including relatively poor time and spatial resolutions, and, frequently, insufficient statistical power for analysis of individual subjects. However, recent technical developments, such as the 3-D acquisition method provide relatively good image quality with a smaller radioactive dosage, which in turn results in more PET scans from each individual, thus providing sufficient statistical power for the analysis of individual subject's data. Furthermore, the noise free scanner environment $H_2^{15}O$ PET, along with discrete acquisition of data for each task condition, are important advantages of PET over other functional imaging methods regarding studying state-dependent changes in brain activity. This review presents both the limitations and advantages of $^{15}O-PET$, and outlines the design of efficient PET protocols, using examples of recent PET studies both in the normal healthy population, and in the clinical population.

• Journal of Pharmaceutical Investigation
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• v.30 no.4
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• pp.299-307
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• 2000

생물학적 동등성 시험은 동일 성분을 동량 함유한 제제가 유사조건에서 투여되었을 경우 그 유효성분이 전신순환혈이나 작용부위에서 유용하게 되는 속도 및 양에 큰 차이가 없음을 입증하는 시험이다. 즉 이미 제조허가 되어 시판중인 의약품과 동일한 품목의 제조허가를 받기 위한 경우이거나 생체이용률이 동일함을 증명하기 위해 실시하는 시험이다. 우리 나라에서는 1989년 1월 1일 이후 허가된 전문의약품으로서 신약과 동일한 의약품, 패취제제, 제제개선을 통해 흡수율을 높이는 경우에 생물학적 동등성 시험을 하도록 의무화하고 있다. 미국 FDA는 1975년 6월 생체이용률, 생물학적 동등성에 관한 규제안을 발표하였고, 우리 나라에서도 1988년 10월에 생물학적 동등성 시험 기준을 제정하였다. 유럽에서는 1991년 12월 CPMP(Committee for Proprietary Medicinal Products)에 의해 최초로 "생체이용률 및 생물학적 동등성에 대한 가이드라인"이 채택되었다. 그후 전문가 회의를 거쳐 규정 전반에 관한 것과 일반적 항목에 대한 검토가 이루어져 최종 개정된 가이드라인이 만들어졌다. 현재 in vivo 생체 이용률을 비교하는 생물학적 동등성 시험의 중요성이 증대되고 있고, 국제적으로도 각 국가별 생물학적 동등성 시험의 평가방법이나 기준설정에 대한 연구가 다양하게 이루어지고 있다. 또한 ICH에서도 생물학적 동등성 시험의 국제적 조화를 위한 시도가 이루어지고 있다. 우리 나라의 현행 생물학적 동등성 기준은 1998년 개정된 것을 사용하고 있으나 국제적 발전 추세에 맞추어 기준의 제고를 모색하고 있다. 그 일환으로 유럽의 "의약품의 생체이용률 및 생물학적 동등성 시험 가이드라인"을 소개하고자 한다., globunlin II의 두 component로 분리(分離)되었고 oryzenin은 시료(試料) 육우(陸羽) 132호(號), 등판(藤坂) 5호(號), 관산(關山) 재건(再建)에서는 oryzenin I, oryzenin II, oryzenin III의 3 component를 분리(分離)하였고 팔달(八達), 진흥(振興), 서광(瑞光), 은방주(銀坊主), 다마금(多摩錦), Pin Galw56의 6시료(試料)에서는 oryzenin II, oryzenin III의 2 component만 분리(分離)하였다. 3. 각(各) fraction을 여지전기영동(濾紙電氣泳動)하여 각(各) component의 농도곡선(濃度曲線)에 의해 함량(含量)을 구(求)한 결과(結果) albumin 0.26%, globulin I, 0.35%, globulin II, 0.32%, prolamin, 0.41%, oryzenin I, 0.30%, oryzenin II, 2.23%, oryzenin III, 2.66%이었다.미국의 경우 3일 이내 전화나 FAX로 보고하고, 10일이내 문서로써 보고하도록 되어 있다. 이러한 임상적 안전성 자료 관리에 대한 신속 보고 정의 및 기준에 대해서는 ICH에서도 논의가 되어 Step 4까지 다다르고 있으므로 앞으로 각 국에서의 적용만 남아있는 상태이고 보면 신약의 개발과 더불어 임상시험에서의 부작용등의 안전성 자료 관리에 대한 중요성은 더욱 강조될 것이다.공하는 음식의 섭취정도에도 영향을 주고 있으므로 학생들에게 학부모와 전담교사 및 학교영양사는 학생들에게 이상적인 아침식사에 대한 교육은 물론이고 아침식사를 실천할 수 있도록 다양한 방안에 대해 함께 연구해야 하겠다. 정부차원에서 학교급식에 아침식사 프로그램을 도입할

• Journal of Chest Surgery
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• v.31 no.9
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• pp.827-836
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• 1998

Background: Effective cardiopulmonary resuscitation (CPR) should provide acceptable hemodynamics for the vital organs during cardiac arrest and early restoration of spontaneous circulation that guarantees long-term, neurologically intact survival. CPR using heart-lung bypass has been suggested as an option for that use. This study was designed to determine the effectiveness of standard CPR techniques, closed-vs. open-chest CPR, which could be used in the future study verifying the role of heart-lung bypass CPR. Material and Method: By using adult mongrel dogs, closed-chest CPR (CCCPR, n=4) and open-chest CPR (OCCPR, n=5) were compared with respects to hemodynamics, restoration of spontaneous circulation(ROSC), and survival. Ventricular fibrillation-cardiac arrest (VF-CA) was induced by electrical shock in all animals. After 4 minutes of cardiac arrest, basic life support (BLS) was applied for 15 minutes and followed by advanced life support (ALS). ALS was maintained until achi ving ROSC but not longer than 30 minutes regardless of the recovery. Resuscitation procedures in either group were standardized by adopting the protocol of American Heart Association. Result: Prearrest baseline hemodynamic data was not different between two groups. During resuscitation, substantially higher systolic pressure was maintained in OCCPR group than in CCCPR group (45$\pm$15 vs. 33$\pm$11 mmHg during BLS, 83$\pm$36 vs. 44$\pm$15 mmHg during ALS; p=NS). Mean pulmonary arterial pressure went up to the level of mean systemic arterial pressures in CCCPR group and to half of that in OCCPR group, and had kept higher in CCCPR group throughout CPR (32$\pm$10 vs. 22$\pm$4 mmHg during BLS and 32$\pm$15 vs. 24$\pm$10 mmHg during ALS; p=NS). ROSC was obtained in 4 of 5 dogs receiving open-chest CPR and 2 of 4 closed-chest CPR. Prolonged survival was noted in all dogs in OCCPR group (6 to 1440 hours) but not in CCPR group (p<.05). Conclusion: These findings indicate that open-chest CPR can be more effective t maintain hemodynamics during cardiac arrest and to obtain restoration of spontaneous circulation and survival. Further experiment will be designed to compare heart-lung bypass CPR with open-chest CPR.

• Journal of Chest Surgery
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• v.31 no.5
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• pp.502-508
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• 1998

Proinflammatory cytokines such as tumor necrosis factor-$\alpha$(TNF-$\alpha$) have been implicated in myocardial and organ dysfunction associated with postperfusion syndrome. We tested the hypothesis that cytokine productions are depressed by preoperative cortiosteroid injection for cardiopulmonary bypass(CPB) and the postoperative courses will be better than without steriod pretreated cases. Cardiac surgery was performed in randomized blind fashion for 20 patients from June 1996 to September 1996. In the steroid group(n=10), corticosteroid(dexamethasone 1 mg/kg) was injected 1 hour before anesthetic induction, but in the control group(n=10), nothing was injected. Each of groups were sampled 11 times as scheduled for TNF-$\alpha$ bioassays. We have checked EKG, cardiac enzymes(CPK, LDH with isoenzyme), WBC count preoperative day, one day and three days after operation. Viatal signs were continuously monitored for three postoperaive days. In the postoperative period three patients in the control group had elevated body temperature and four patients had hypotension that required considerable intravenous fluid administration. But steroid injected patients showed normal body temperture and acceptable blood pressures without supportive treatment. CPK enzymes rose in control group higher than steroid group at postoperative 1st and 3rd day(CPK; 1122$\pm$465 vs 567$\pm$271, 864$\pm$42 vs 325$\pm$87), and CPK-MB enzymes rose in control group higher than steroid group at postoperative 1st day(106.4$\pm$115.1 vs 29.5$\pm$22.4)(P=0.02). Arterial tumor necrosis factor-$\alpha$ rose during cardiopulmonary bypass, peaking at 5 minutes before the end of aortic cross clamping(ACC-5min) in steroid group(11.9$\pm$4.7 pg/ml), and 5 minutes before the end of cardiopulmonary bypass(CPB-5min) in control group(22.3$\pm$6.8 pg/ml). The steroid pretreated patients had a shorter period of time in respirator suport time, ICU stay day, hospital admission day. We conclude that corticosteroid suppress cytokine production during and after cardiopulmonary bypass, and may improve the postoperative course through inhibition of reperfusion injury such as myocardial stunning and hemodynamic instability.

• Radiation Oncology Journal
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• v.29 no.1
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• pp.11-19
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• 2011

Purpose: To evaluate the pathological and clinical effects of preoperative chemoradiation (CCRT) in cases of locally advanced rectal cancer and to determine the predictive factors for tumor downstaging. Materials and Methods: From March 2004 to August 2008, 33 patients with locally advanced rectal cancer were treated with preoperative CCRT. Twenty-eight patients (84.8%) were treated using a concomitant boost technique while five (15.2%) patients were treated using a cone down boost technique. All patients received 50.4 Gy of irradiation and concurrent chemotherapy with 5-fluorouracil. The median follow-up duration was 24.2 months (range, 9.8 to 64.7 months). Results: Thirty-one (93.9%) patients underwent surgery. Twenty-four patients (72.7%) underwent anal sphincter-preserving surgery. The 3-year disease free survival (DFS) and overall survival rates were 63.4% and 78.8%, respectively. Post-operative factors were more important for DFS. Pathologic N stage, margin status, and pathologic differentiation were significant prognostic factors (p=0.001, 0.029, 0.030). Tumor size and lymphovascular invasion were also associated with marginal significance (p=0.081, 0.073). However, only pre-treatment T stage was a significant pre-operative factor (p=0.018). The complete pathological response rate was 9.1 %. T-downstaging was observed in ten (30.3%) patients, whereas N-downstaging was found in 24 (72.7%) patients. Pre-treatment T stage and the interval between CCRT and operation were the predictive factors for downstaging in a univariate analysis (p=0.029, 0.027). Pre-treatment carcinoembryogenic antigen was also associated with marginal significance (p=0.068). Conclusion: The survival of rectal cancer patients can be better determined based on post-operative findings. Therefore, pre-operative CCRT for downstaging of the tumor seems to be important. Pre-treatment T stage and the interval between CCRT and operation can be used to predict downstaging.

• Radiation Oncology Journal
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• v.19 no.3
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• pp.265-274
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• 2001

Purpose : Proctitis is one of acute complications encountered when radiotherapy was appled to the pelvis. Radiation-induced proctitis represents similar microscopic findings that are observed in inflammatory bowel disease (IBD). Nitric oxide (NO) plays an important role in the inflammatory process and many data suggest a close relationship between NO production and gastrointestinal inflammation. This study was aimed to establish the optimal radiation dose for radiation-induced proctitis in rat and to find a relationship between radiation proctitis and NO production. Materials and methods : Female Wistar rats, weighing from 150 to 220 g, received various doses(10-30 Gy) of radiation to the rectum. On the 5th and 10th day after irradiation, rectal specimens were evaluated grossly and microscopically. In addition, the degree of NO production by irradiation dose was evaluated by study with NOS expression and nitrite production in the irradiated rectal tissue. To evaluate relationship between radiation proctitis and NO, we administered aminoguanidine, iNOS inhibitor and L-arginine, substrate of NOS to rats from 2 days before to 7 days after the irradiation. Results : There were obvious gross and hostological changes after 17.5 Gy or higher radiation dose but not with 15 Gy or less radiation dose. Twenty Gy or higher dose of radiation caused Grade 4 damage in most of rectal specimens which were more likely to be related to the late complications such as fibrosis, rectal bleeding and rectal obstruction. A single fraction of 17.5 Gy to the rat rectum is considered to be an optimal dose to produce commonly experienced proctitis in the clinic. The result demonstrated that severity of microscopic damage of rectal mucosa from irradiation significantly correlated with iNOS over-expression. However, administration of iNOS inhibitor or substrate of iNOS did not influence the degree of rectal damage. Conclusion : A single fraction of 17.5 Gy irradiation to the rat rectum considered to be an optimal dose for radiation induced proctitis model. These results indicated that an excess production of NO contributes to pathogenesis of radiation-induced proctitis in part but was not the direct cause of rectal damage.

• Radiation Oncology Journal
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• v.13 no.3
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• pp.291-296
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• 1995

Purpose : In general, the wedge factors which are used clinical practices are ignored of dependency on field sizes and depths. In this present, we investigated systematically the depth and field size dependency to determine the absorbed dose more accurately. Methods : The wedge factors for each wedge filter were measured at various depths (depth of Dmax, 5cm, 10cm, and 15cm) and field sizes ($5cm{\times}5cm,\;10cm{\times}10cm,\;15cm{\times}15cm, and 20cm{\times}20cm$) by using 4-, 6-, and 10-MVX rays. By convention, wedge factors are determined by taking the ratio of the central axis ionization readings when the wedge filter is in place to those of the open field in same field size and measurement depth. In this present work, we determined the wedge factors for 4-, 6-, and 10-MV X rays from Clinac 600C and 2100C linear accelerators (manufactured by Varian Associates, Inc., Palo Alto, CA). To confirm that the wedge was centered, measurements were done with the two possible wedge position and various collimator orientations. Results : The standard deviations of measured values are within $0.3\;\%$ and the depth dependence of wedge factor is greater for the lower energies. Especially, the variation of wedge factor is no less than $5\%$ for 4- and 6- MV X rays with more than $45^{\circ}$ wedge filters. But there seems to be a small dependence on field size. Conclusion : The results of this study show a dependence on the point of measurement. There also seems to be a small dependence on field size. And so, we should consider the depth and field size dependence in determining the wedge factors. If one wedge factor were to be used for each wedge filter it seems that the measurement for a 10cm x 10cm field size at a depth of loom would be a reasonable choice.

• Pediatric Infection and Vaccine
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• v.24 no.2
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• pp.71-78
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• 2017

Purpose: The aim of this study was to identify the pathogens of blood stream infection (BSI) in children with hemato-oncologic disorders, to analyze susceptibility patterns of microorganisms to guide empirical antimicrobial therapy, and to compare temporal trends of the pathogen and antimicrobial susceptibility with those of previous studies. Methods: We retrospectively analyzed the medical records of children with hemato-oncologic disorders whose blood culture grew pathogens at the Seoul National University Children's Hospital between 2011 and 2015. Results: A total of 167 patients developed 221 episodes of bacteremia. Among 229 pathogens, gram-negative bacteria (GNB) accounted for 69.0% (64.0% in 2002 to 2005, 63.4% in 2006 to 2010); gram-positive bacteria (GPB) accounted for 28.8% (31.3% in 2002 to 2005, 34.6% in 2006 to 2010); and fungus accounted for 2.2%. Among GNB, Klebsiella species (53.2%, 84/158) and Escherichia coli (19.6%, 31/158) were common. Staphylococcus aureus (48.5%, 32/66) and viridans streptococci (21.2%, 14/66) were frequently isolated among GPB. The susceptibilities of oxacillin and vancomycin in GPB were 54.8% and 96.9% (51.5% and 95.5% in 2002 to 2005; 34.1% and 90.5% in 2006 to 2010), respectively, whereas in GNB, the susceptibilities of cefotaxime, piperacillin/tazobactam, and imipenem were 73.2%, 77.2%, and 92.6% (75.9%, 82.8%, and 93.4% in 2002 to 2005; 62.8%, 82.9%, 93.8% and in 2006 to 2010), respectively. There were no significant differences in the proportion of etiologic agents or the antimicrobial susceptibilities between the current study and that of the previous two studies from 2002 to 2010. Overall fatality rate was 13.1%. Conclusions: GNB predominated in BSI among children with hemato-oncologic disorders. The etiology of bacteremia and antimicrobial susceptibility were comparable to those of the previous studies. Thus, piperacillin/tazobactam can be used as the initial empirical antimicrobial agent in febrile neutropenia.

• Journal of Life Science
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• v.17 no.5 s.85
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• pp.634-640
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• 2007

Our previous study suggested that n-3 fatty acid deficiency was associated with significantly reduced spatial learning as assessed by Morris water maze test. Here we investigated an effect of n-3 fatty acid deficiency on rat brain, retina and serum fatty acyl compositions at 15 wks age using a first generational artificial rearing technique. Newborn Rat pups were separated on day 2 and assigned to two artificial rearing groups or a dam-reared control group. Pups were hand fed artificial milk via custom-designed nursing bottles containing either 0.02%(n-3 Deficient) or 3.1% (n-3 Adequate) of total fatty acids as a-linolenic acid(LNA). At day 21, rats were weaned to either n-3 deficient or n-3 adequate pelleted diets and fatty acid compositions of brain, retina and liver were analyzed at 15 wks age. Brain docosahexaenoic acid(DHA) was lower(58% and 61%, P<0.05) in n-3 deficient in comparison to n-3 adequate and dam-reared groups, receptively, while brain docosapentaenoic acid(DPAn-6) was increased in the n-3 deficient group. In retina and serum fatty acid compositions, the decreased precentage of DHA and increased precentage of DPAn-6 were observed. These results suggested that artificial rearing method can be used to produce n-3 fatty acid deficiency in the first generation and that adequate brain DHA levels are required for optimal brain function.

• The Korean Journal of Nuclear Medicine
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• v.36 no.6
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• pp.381-391
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• 2002

Purpose: The presence of perfusion defect may influence the left ventricular mass (LVM) measurement by quantitative gated myocardial perfusion SPECT (QGS), and ischemic myocardium, usually showing perfusion defect may produce post-stress LV dysfunction. This study was aimed to evaluate the effects of extent and reversibility of perfusion defect on the automatic measurement of LVM by QGS and to investigate the effect of reversibility of perfusion defect on post-stress LV dysfunction. Subjects and Methods: Forty-six patients (male/female=34:12, mean age=64years) with perfusion defect on myocardial perfusion SPECT underwent rest and post-stress QGS. Forty patients (87%) showed reversible defect. End-diastolic volume (EDV), end-systolic volume (ESV), LV ejection fraction (EF), and LV myocardial volume were obtained from QGS by AutoQUANT program, and LVM was calculated by multiplying the LV myocardial volume by the specific gravity of myocardium. Results: LVMs measured at rest and post-stress QGS showed good correlation, and higher correlation was founded in the subjects with fixed perfusion defect and with small defect (smaller than 20%). There were no significant differences in EDVs, ESVs and EFs between obtained by rest and post-stress QGS un patients with fixed myocardial defect. Whereas, EF obtained by post-stress QGS was lower than that by rest QGS in patients with reversible defect and 10 (25%) of them showed decreases in EF more than 5% in post-stress QGS, as compared to that of rest QGS. Excellent correlations of EDVs, ESVs, EFs between rest and post-stress QGS were noted. Patients with fixed defect had higher correlation between EDVs, ESVs, EFs than patients with reversible defect. Conclusion: These results suggest that perfusion defect can affect LVM measurement by QGS and patients with reversible defect shows post-stress LV dysfunction more frequently than patients with fixed perfusion defect.