• 한국산림과학회지
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• 제112권4호
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• pp.554-560
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• 2023

불법 목재 유통을 막기 위해 DNA를 활용한 수종 및 원산지 식별이 이루어지고 있지만, 목재의 물리·화학적 특성 때문에 양질의 DNA를 얻기 어렵다. 본 연구에서는 목재 DNA 추출 수율과 polymerase chain reaction (PCR) 성공률에 목재 조직의 나이가 영향을 미치는지 알아보기 위하여, 국내 주요 수종인 소나무 원목에서 DNA를 추출하여, 목재의 나이테 생성 시기와 추출 DNA 농도(ng/μl) 및 순도(A260/A280) 그리고 PCR 성공률(%)의 관계를 확인하였다. 분석 결과, 나이테가 형성층으로부터 멀어질수록, 즉 오래 전에 생성된 목재일수록, 추출한 DNA의 농도와 순도는 유의하게 감소하였다. 증폭 길이가 짧은 trnM-trnV(285 bp) 영역과 rpoC1(298 bp) 영역의 경우 PCR 증폭 성공률이 100 %였으나, rbcL(1.3 kb) 영역의 경우 66.67 %였고 30년보다 오래된 조직에서는 모두 증폭에 실패하였다. 시간이 지남에 따라 목재 세포의 사멸과 함께 양질의 DNA가 파괴되어 DNA 농도, 순도, PCR 성공률이 감소한 것으로 판단된다. 본 연구 결과는 향후 목재를 활용한 수종 동정 등에 유용하게 활용될 것으로 기대된다.

• Korean Journal of Radiology
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• 제22권9호
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• pp.1451-1461
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• 2021

Objective: Adequate methods of combining T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) to assess complete response (CR) to chemoradiotherapy (CRT) for rectal cancer are obscure. We aimed to determine an algorithm for combining T2WI and DWI to optimally suggest CR on MRI using visual assessment. Materials and Methods: We included 376 patients (male:female, 256:120; mean age ± standard deviation, 59.7 ± 11.1 years) who had undergone long-course CRT for rectal cancer and both pre- and post-CRT high-resolution rectal MRI during 2017-2018. Two experienced radiologists independently evaluated whether a tumor signal was absent, representing CR, on both post-CRT T2WI and DWI, and whether the pre-treatment DWI showed homogeneous hyperintensity throughout the lesion. Algorithms for combining T2WI and DWI were as follows: 'AND,' if both showed CR; 'OR,' if any one showed CR; and 'conditional OR,' if T2WI showed CR or DWI showed CR after the pre-treatment DWI showed homogeneous hyperintensity. Their efficacies for diagnosing pathologic CR (pCR) were determined in comparison with T2WI alone. Results: Sixty-nine patients (18.4%) had pCR. AND had a lower sensitivity without statistical significance (vs. 62.3% [43/69]; 59.4% [41/69], p = 0.500) and a significantly higher specificity (vs. 87.0% [267/307]; 90.2% [277/307], p = 0.002) than those of T2WI. Both OR and conditional OR combinations resulted in a large increase in sensitivity (vs. 62.3% [43/69]; 81.2% [56/69], p < 0.001; and 73.9% [51/69], p = 0.008, respectively) and a large decrease in specificity (vs. 87.0% [267/307]; 57.0% [175/307], p < 0.001; and 69.1% [212/307], p < 0.001, respectively) as compared with T2WI, ultimately creating additional false interpretations of CR more frequently than additional identification of patients with pCR. Conclusion: AND combination of T2WI and DWI is an appropriate strategy for suggesting CR using visual assessment of MRI after CRT for rectal cancer.

• Korean Journal of Radiology
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• 제22권2호
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• pp.213-224
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• 2021

Objective: Clinical outcomes of patients who undergo transarterial chemoembolization (TACE) for single small hepatocellular carcinoma (HCC) are not consistent, and may differ based on certain imaging findings. This retrospective study was aimed at determining the efficacy of pre-TACE CT or MR imaging findings in predicting survival outcomes in patients with small HCC upon being treated with TACE. Besides, the study proposed to build a risk prediction model for these patients. Materials and Methods: Altogether, 750 patients with functionally good hepatic reserve who received TACE as the first-line treatment for single small HCC between 2004 and 2014 were included in the study. These patients were randomly assigned into training (n = 525) and validation (n = 225) sets. Results: According to the results of a multivariable Cox analysis, three pre-TACE imaging findings (tumor margin, tumor location, enhancement pattern) and two clinical factors (age, serum albumin level) were selected and scored to create predictive models for overall, local tumor progression (LTP)-free, and progression-free survival in the training set. The median overall survival time in the validation set were 137.5 months, 76.1 months, and 44.0 months for low-, intermediate-, and high-risk groups, respectively (p < 0.001). Time-dependent receiver operating characteristic curves of the predictive models for overall, LTP-free, and progression-free survival applied to the validation cohort showed acceptable areas under the curve values (0.734, 0.802, and 0.775 for overall survival; 0.738, 0.789, and 0.791 for LTP-free survival; and 0.671, 0.733, and 0.694 for progression-free survival at 3, 5, and 10 years, respectively). Conclusion: Pre-TACE CT or MR imaging findings could predict survival outcomes in patients with small HCC upon treatment with TACE. Our predictive models including three imaging predictors could be helpful in prognostication, identification, and selection of suitable candidates for TACE in patients with single small HCC.

• Korean Journal of Radiology
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• 제23권10호
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• pp.1009-1018
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• 2022

Objective: This study aimed to investigate the feasibility of using artificial intelligence (AI) to identify normal chest radiography (CXR) from the worklist of radiologists in a health-screening environment. Materials and Methods: This retrospective simulation study was conducted using the CXRs of 5887 adults (mean age ± standard deviation, 55.4 ± 11.8 years; male, 4329) from three health screening centers in South Korea using a commercial AI (Lunit INSIGHT CXR3, version 3.5.8.8). Three board-certified thoracic radiologists reviewed CXR images for referable thoracic abnormalities and grouped the images into those with visible referable abnormalities (identified as abnormal by at least one reader) and those with clearly visible referable abnormalities (identified as abnormal by at least two readers). With AI-based simulated exclusion of normal CXR images, the percentages of normal images sorted and abnormal images erroneously removed were analyzed. Additionally, in a random subsample of 480 patients, the ability to identify visible referable abnormalities was compared among AI-unassisted reading (i.e., all images read by human readers without AI), AI-assisted reading (i.e., all images read by human readers with AI assistance as concurrent readers), and reading with AI triage (i.e., human reading of only those rendered abnormal by AI). Results: Of 5887 CXR images, 405 (6.9%) and 227 (3.9%) contained visible and clearly visible abnormalities, respectively. With AI-based triage, 42.9% (2354/5482) of normal CXR images were removed at the cost of erroneous removal of 3.5% (14/405) and 1.8% (4/227) of CXR images with visible and clearly visible abnormalities, respectively. In the diagnostic performance study, AI triage removed 41.6% (188/452) of normal images from the worklist without missing visible abnormalities and increased the specificity for some readers without decreasing sensitivity. Conclusion: This study suggests the feasibility of sorting and removing normal CXRs using AI with a tailored cut-off to increase efficiency and reduce the workload of radiologists.

• 방사선산업학회지
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• 제17권4호
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• pp.345-357
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• 2023

Nuclear forensics has been understood as a mendatory component in the international society for nuclear material control and non-proliferation verification. Radiochronometry of nuclear activities for nuclear forensics are decay series characteristics of nuclear materials and the Bateman equation to estimate when nuclear materials were purified and produced. Radiochronometry values have uncertainty of measurement due to the uncertainty factors in the estimation process. These uncertainties should be calculated using appropriate evaluation methods that are representative of the accuracy and reliability. The IAEA, US, and EU have been researched on radiochronometry and uncertainty of measurement, although the uncertainty calculation method using the Bateman equation is limited by the underestimation of the decay constant and the impossibility of estimating the age of more than one generation, so it is necessary to conduct uncertainty calculation research using computer simulation such as Monte Carlo method. This highlights the need for research using computational simulations, such as the Monte Carlo method, to overcome these limitations. In this study, we have analyzed mathematical models and the LHS (Latin Hypercube Sampling) methods to enhance the reliability of radiochronometry which is to develop an uncertainty algorithm for nuclear material radiochronometry using Bateman Equation. We analyzed the LHS method, which can obtain effective statistical results with a small number of samples, and applied it to algorithms that are Monte Carlo methods for uncertainty calculation by computer simulation. This was implemented through the MATLAB computational software. The uncertainty calculation model using mathematical models demonstrated characteristics based on the relationship between sensitivity coefficients and radiative equilibrium. Computational simulation random sampling showed characteristics dependent on random sampling methods, sampling iteration counts, and the probability distribution of uncertainty factors. For validation, we compared models from various international organizations, mathematical models, and the Monte Carlo method. The developed algorithm was found to perform calculations at an equivalent level of accuracy compared to overseas institutions and mathematical model-based methods. To enhance usability, future research and comparisons·validations need to incorporate more complex decay chains and non-homogeneous conditions. The results of this study can serve as foundational technology in the nuclear forensics field, providing tools for the identification of signature nuclides and aiding in the research, development, comparison, and validation of related technologies.

• Journal of Animal Science and Technology
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• 제66권4호
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• pp.682-701
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• 2024

This study estimated the heritabilities (h²) and genetic and phenotypic correlations between reproductive traits, including calving interval (CI), age at first calving (AFC), gestation length (GL), number of artificial inseminations per conception (NAIPC), and carcass traits, including carcass weight (CWT), eye muscle area (EMA), backfat thickness (BF), and marbling score (MS) in Korean Hanwoo cows. In addition, the accuracy of genomic predictions of breeding values was evaluated by applying the genomic best linear unbiased prediction (GBLUP) and the weighted GBLUP (WGBLUP) method. The phenotypic data for reproductive and carcass traits were collected from 1,544 Hanwoo cows, and all animals were genotyped using Illumina Bovine 50K single nucleotide polymorphism (SNP) chip. The genetic parameters were estimated using a multi-trait animal model using the MTG2 program. The estimated h² for CI, AFC, GL, NAIPC, CWT, EMA, BF, and MS were 0.10, 0.13, 0.17, 0.11, 0.37, 0.35, 0.27, and 0.45, respectively, according to the GBLUP model. The GBLUP accuracy estimates ranged from 0.51 to 0.74, while the WGBLUP accuracy estimates for the traits under study ranged from 0.51 to 0.79. Strong and favorable genetic correlations were observed between GL and NAIPC (0.61), CWT and EMA (0.60), NAIPC and CWT (0.49), AFC and CWT (0.48), CI and GL (0.36), BF and MS (0.35), NAIPC and EMA (0.35), CI and BF (0.30), EMA and MS (0.28), CI and AFC (0.26), AFC and EMA (0.24), and AFC and BF (0.21). The present study identified low to moderate positive genetic correlations between reproductive and CWT traits, suggesting that a heavier body weight may lead to a longer CI, AFC, GL, and NAIPC. The moderately positive genetic correlation between CWT and AFC, and NAIPC, with a phenotypic correlation of nearly zero, suggesting that the genotype-environment interactions are more likely to be responsible for the phenotypic manifestation of these traits. As a result, the inclusion of these traits by breeders as selection criteria may present a good opportunity for developing a selection index to increase the response to the selection and identification of candidate animals, which can result in significantly increased profitability of production systems.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• 제25권1호
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• pp.50-61
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• 2023

Objective: To describe the roadmapping technique and our three-year experience in the management of intracranial aneurysms in the hybrid operating room. Methods: We analyzed all patients who underwent surgical clipping for cerebral aneurysms with the roadmapping technique from January 2017 to September 2019. We report demographic, clinical, and morphological variables, as well as clinical and radiological outcomes. We further describe three illustrative cases of the technique. Results: A total of 13 patients were included, 9 of which (69.2%) presented with subarachnoid hemorrhage, with a total of 23 treated aneurysms. All patients were female, with a mean age of 47.7 years (range 31-63). All cases were anterior circulation aneurysms, the most frequent location being the ophthalmic segment of the internal carotid artery (ICA) in 11 cases (48%), followed by posterior communicating in 8 (36%), and ICA bifurcation in 2 (8%). Intraoperative clip repositioning was required in 9 aneurysms (36%) as a result of the roadmapping technique in the hybrid operating room. There were no residual aneurysms in our series, nor reported mortality. Conclusions: The roadmapping technique in the hybrid operating room offers a complementary tool for the adequate occlusion of complex intracranial aneurysms, as it provides a real time fluoroscopic-guided clipping technique, and clip repositioning is possible in a single surgical stage, whenever a residual portion of the aneurysm is identified. This technique also provides some advantages, such as immediate vasospasm identification and treatment with intra-arterial vasodilators, balloon proximal control for certain paraclinoid aneurysms, and simultaneous endovascular treatment in selected cases during a single stage.

• Journal of Korean Neurosurgical Society
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• 제67권5호
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• pp.510-520
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• 2024

Objective : Parkinson's disease (PD) is one of the most prevalent neurodegenerative diseases, characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta. The treatment of PD aims to alleviate motor symptoms by replacing the reduced endogenous dopamine. Currently, there are no disease-modifying agents for the treatment of PD. Zebrafish (Danio rerio) have emerged as an effective tool for new drug discovery and screening in the age of translational research. The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is known to cause a similar loss of dopaminergic neurons in the human midbrain, with corresponding Parkinsonian symptoms. L-type calcium channels (LTCCs) have been implicated in the generation of mitochondrial oxidative stress, which underlies the pathogenesis of PD. Therefore, we investigated the neuro-restorative effect of LTCC inhibition in an MPTP-induced zebrafish PD model and suggested a possible drug candidate that might modify the progression of PD. Methods : All experiments were conducted using a line of transgenic zebrafish, Tg(dat:EGFP), in which green fluorescent protein (GFP) is expressed in dopaminergic neurons. The experimental groups were exposed to 500 μmol MPTP from 1 to 3 days post fertilization (dpf). The drug candidates : levodopa 1 mmol, nifedipine 10 μmol, nimodipine 3.5 μmol, diethylstilbestrol 0.3 μmol, luteolin 100 μmol, and calcitriol 0.25 μmol were exposed from 3 to 5 dpf. Locomotor activity was assessed by automated tracking and dopaminergic neurons were visualized in vivo by confocal microscopy. Results : Levodopa, nimodipine, diethylstilbestrol, and calcitriol had significant positive effects on the restoration of motor behavior, which was damaged by MPTP. Nimodipine and calcitriol have significant positive effects on the restoration of dopaminergic neurons, which were reduced by MPTP. Through locomotor analysis and dopaminergic neuron quantification, we identified the neuro-restorative effects of nimodipine and calcitriol in zebrafish MPTP-induced PD model. Conclusion : The present study identified the neuro-restorative effects of nimodipine and calcitriol in an MPTP-induced zebrafish model of PD. They restored dopaminergic neurons which were damaged due to the effects of MPTP and normalized the locomotor activity. LTCCs have potential pathological roles in neurodevelopmental and neurodegenerative disorders. Zebrafish are highly amenable to high-throughput drug screening and might, therefore, be a useful tool to work towards the identification of disease-modifying treatment for PD. Further studies including zebrafish genetic models to elucidate the mechanism of action of the disease-modifying candidate by investigating Ca2+ influx and mitochondrial function in dopaminergic neurons, are needed to reveal the pathogenesis of PD and develop disease-modifying treatments for PD.

• Clinical and Experimental Pediatrics
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• 제48권4호
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• pp.395-400
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• 2005

목 적 : Rotavirus는 국내뿐 아니라 전 세계적으로 영 유아 급성 설사의 가장 흔한 원인이며 또한 영유아기의 원내 감염의 가장 중요한 원인 중 하나이다. 본 연구의 목적은 rotavirus 원내 감염의 위험 인자와 모유 수유 및 정장제 등이 원내 감염에 미치는 영향을 알아보고, rotavirus 원내 감염의 불현성 감염률과 퇴원 후 증상 발현율 등에 대해 연구하기 위한 것이다. 방 법 : 2003년 3월부터 2004년 2월 사이에 전주예수병원 소아과에 설사증 이외의 질환으로 입원한 환아 중 3회 이상 대변 검사를 하였던 390명을 대상으로, 입원 기간과 퇴원 후 3일째 대변 검사에서 rotavirus 항원 양성이었던 환아를 원내 감염군으로 하고, 비감염군은 입원 기간과 퇴원 후 3일까지 설사 증상이 없고 rotavirus 항원 검사 음성이었던 환아로 하여 rotavirus 원내 감염의 위험인자를 관찰하였다. 대변 검사는 입원 첫날 latex 응집반응 검사법으로 rotavirus 항원을 검사하였다. 입원 첫날 대변에서 세균 배양 검사와 rotavirus 항원 검사가 음성인 환아에서 rotavirus 원내 감염을 알기 위하여 입원 4일째, 그 후 입원 기간동안 매주 1회, 퇴원 후 3일째 대변을 채취하여 rotavirus 항원을 검사하였다. 입원 72시간 이후에 설사증이 있는 환아는 설사 발현 즉시 신선한 대변을 채취하여 rotavirus 항원 검사를 실시하였다. 결 과 : Rotavirus 원내 감염군은 30명이었고, 비감염군은 246명이었다. 연령별로는 12개월 이하에서 15.8%이었으며, 13개월 이상에서 5.8%로 12개월 이하에서 발생이 많았으며 통계학적 차이가 있었다(P=0.008). 계절별로는 12월부터 3월 사이에 입원한 환아에서 16.5%이었으며, 4월과 11월 사이에 입원한 환아에서 8.4%로 통계학적 차이가 있었다(P=0.046). 평균입원기간은 rotavirus 원내 감염군에서 $10.2{\pm}5.6$일이었으며 비감염군에서 $8.0{\pm}3.4$일로 통계학적 차이가 있었다(P=0.003). 그러나 본 연구에서 rotavirus 원내 감염은 입원 병실, 모유 수유나 정장제 사용여부와는 관련이 없는 것으로 나타났다. 결 론 : 이상의 결과로 rotavirus 원내 감염은 12개월 이하의 환아에서, 12월부터 3월 사이에 많이 발생하고 입원기간이 길수록 많이 발생하며, 불현성 감염과 퇴원 후 증상이 나타나는 경우도 많이 있어, 이들 환아에서 적절한 관리를 통해 예방에 더욱 힘써야 할 것으로 생각된다.

• Journal of Korean Neurosurgical Society
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• 제30권6호
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• pp.705-710
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• 2001

목 적 : 파열된 뇌동맥류 수술후 경련발작은 잘 알려진 합병증으로 항경련제 치료가 요구된다. 저자들은 뇌동맥류 파열에 의한 지주막하출혈 환자에서 수술후 경련발작의 위험인자를 조사하여 경련발작 치료에 임상적 의의를 비교 하고자 한다. 방 법 : 1990년부터 1996년까지 파열된 뇌동맥류로 개두술을 시행한 321명의 환자중 1년 이상 추적관찰(1~4.6년)하였던 206명을 대상으로 후향적 방법으로 조사하였다. 모든 환자는 수술후 3~18개월 동안 예방적 항경련제 치료를 받았다. 경련발작에 기여하는 요인으로서 연령, 성별, 내원 당시 신경학적 상태, 수술전후 전산화단층촬영소견, Hunt-Hess grade, Fisher grade, 뇌동맥류의 위치, 고혈압의 기왕력, 수술시기, 그리고 지연성 신경학적 결손 등을 조사하여 비교 분석하였다. 통계적 검증분석 방법으로 chi-square test와 Fisher's exact test를 이용하였다. 결 과 : 평균 추적관찰기간은 1.8년으로 206명중 18명이 경련발작 소견을 보여 8.7%의 발생률을 보였다. 연령에서 나이가 적을수록, 파열된 동맥류의 위치가 중뇌동맥인 경우에서 경련발작이 높게 나타났다. 지연성 신경학적 결손을 보인 42명의 환자에서 8명(19%)이 경련발작이 발생하여 높은 통계학적 유의성을 보였다. 또한 고혈압의 기왕력, 수술후 뇌전산화촬영상 뇌경색등도 이와 관련성이 있었고, 수술전후 뇌내혈종의 소견이 관찰되면 또한 경련발작이 높게 발생되었다. 그러나 Hunt-Hess grade, Fisher grade, Glasgow Outcome Scale, 그리고 출혈후 수술의 시기 등은 경련발작의 발생빈도와는 통계학적 유의성을 보이지 않았다. 결 론 : 뇌동맥류 파열에 의한 수술후 경련발작의 위험인자로 낮은 연령, 중뇌동맥류, 지연성 신경학적 결손, 수술후 뇌전산화촬영상 뇌경색소견, 고혈압, 그리고 수술전후 뇌내혈종의 유무 등이 연관되었고, 이러한 경련발작의 유발인자를 인지함으로서 수술후 경련발작에 대한 예방과 치료에 도움을 줄 수가 있으며 이에 대한 전향적 연구가 요구된다.