• Korean Journal of Radiology
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• 제22권9호
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• pp.1537-1546
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• 2021

Objective: To assess the role of arterial spin-labeling (ASL) perfusion MRI in identifying cerebral perfusion changes after indirect revascularization in children with moyamoya disease. Materials and Methods: We included pre- and postoperative perfusion MRI data of 30 children with moyamoya disease (13 boys and 17 girls; mean age ± standard deviation, 6.3± 3.0 years) who underwent indirect revascularization between June 2016 and August 2017. Relative cerebral blood flow (rCBF) and qualitative perfusion scores for arterial transit time (ATT) effects were evaluated in the middle cerebral artery (MCA) territory on ASL perfusion MRI. The rCBF and relative time-to-peak (rTTP) values were also measured using dynamic susceptibility contrast (DSC) perfusion MRI. Each perfusion change on ASL and DSC perfusion MRI was analyzed using the paired t test. We analyzed the correlation between perfusion changes on ASL and DSC images using Spearman's correlation coefficient. Results: The ASL rCBF values improved at both the ganglionic and supraganglionic levels of the MCA territory after surgery (p = 0.040 and p = 0.003, respectively). The ATT perfusion scores also improved at both levels (p < 0.001 and p < 0.001, respectively). The rCBF and rTTP values on DSC MRI showed significant improvement at both levels of the MCA territory of the operated side (all p < 0.05). There was no significant correlation between the improvements in rCBF values on the two perfusion images (r = 0.195, p = 0.303); however, there was a correlation between the change in perfusion scores on ASL and rTTP on DSC MRI (r = 0.701, p < 0.001). Conclusion: Recognizing the effects of ATT on ASL perfusion MRI may help monitor cerebral perfusion changes and complement quantitative rCBF assessment using ASL perfusion MRI in patients with moyamoya disease after indirect revascularization.

• 한국통신학회논문지
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• 제37권8B호
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• pp.695-705
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• 2012

무선 단말과 자동차 산업의 발전으로 도로 위의 차량들이 데이터 전달의 주체가 되는 차량 애드 혹 네트워크(Vehicular Ad hoc Networks, VANET)에 대한 연구가 활발하다. 차량에 의해 전달되는 데이터는 승객/운전자의 안전 및 교통 혼잡에 영향을 주는 긴급한 정보를 포함하고 있으므로 빠르고 신뢰성 있게 전달되어야 하고, 이를 위한 라우팅 프로토콜은 VANET의 성능에 큰 영향을 미친다. 이에 본 논문에서는 데이터 전달에 참여하는 차량의 이동 방향이 성능이 미치는 영향을 살펴보고, 이를 기반으로 신호등이 있는 도로에서 빠르고 신뢰성 있게 메시지를 전파하기 위해 CBF(Contention-Based Forwarding)를 확장하는 방안을 제안한다. 제안하는 방안은 신호등이 있는 도로에서 메시지 전파의 신뢰성을 높이면서도 전달 차량 간의 위치 관계 변화에 의한 라우팅 루프와 메시지 전달이 중단되는 등의 문제를 발생시키지 않는다. 또한 시뮬레이션을 통하여 제안하는 방안을 적용한 CBF(R-CBF)와 기존 연구 중 메시지 전달의 신뢰성을 향상시키되 메시지 전파 방향과 반대로 이동하는 차량을 전달 차량으로 선택하는 G-SRMB의 성능을 비교하여 R-CBF가 G-SRMB에 비해 메시지 전파 지연 시간을 최대 38% 감소시키고, 불필요한 재전송 없이 동작함을 확인하였다.

• 동의생리병리학회지
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• 제21권1호
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• pp.54-61
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• 2007

The study was designed to investigate the effects of Mixture of Yukgunja-tang and Bambusae Caulis in Liquamen (YTBCL) on the change of regional cerebral blood flow (rCBF) and mean arterial blood pressure (MABP) in rats, and further to determine the mechanism of action of YTBCL. The results in rats were as follows ; YTBCL 25 ${\mu}l$ significantly decreased rCBF and MABP compared with basal condition. YTBCL 100 ${\mu}l$ significantly increased rCBF compared with basal condition, but decreased MABP compared with basal condition. YTBCL 50 ${\mu}l$ significantly increased rCBF compared with basal condition, but MABP was somewhat decreased compared with basal condition. The VTBCL 50 ${\mu}l$-induced increase in rCBF was significantly inhibited by pretreatment with methylene blue (10 ${\mu}g$/kg, i.p.), an inhibitor of guanylate cyclase and indomethacin (1 mg/kg, i.p.), an inhibitor of cyclooxygenase. The YTBCL 50 ${\mu}l$-induced decreased MABP significantly increased by pretreatment with methylene blue but was inhibited by indomethacin. This results were suggested that the mechanism of YTBCL was mediated Dy guanylate cyclase.

• 한국조리학회지
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• 제20권5호
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• pp.67-70
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• 2014

The purpose of this study was to measure the changes of regional cerebral blood flow(rCBF) and blood pressure(BP) in rats, following the intravenous injection of Flos Sophora japonica L.(FSJ) water extract. The measurement was continually monitored by Laser-Doppler Flowmeter and pressure transducer in anaesthetized adult Sprague-Dawley rats for 2 hours to 2 hours and a half through the data acquisition system. FSJ increased the changes of rCBF in rat significantly. The rCBF of FSJ did not change by pretreated propranolol, atropine, L-NNA($N^G$-nitro-L-argininine) and indomethacin. But the rCBF of Flos Sophora japonica L. was increased by pretreated methylene blue. FSJ decreased the changes of BP, significantly. The BP of FSJ did not change by pretreated propranolol, atropine, L-NNA and indomethacin. But the BP FSJ was decreased by pretreated methylene blue. There results indicated that FSJ can increase the rCBF and decrease the BP, that is related to guanylyl cyclase activity.

• 동의생리병리학회지
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• 제18권4호
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• pp.1014-1020
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• 2004

The study was designed to investigate the effects of Palmul-Tang(PMT) on the change of cerebral hemodynamics [regional cerebral blood flow(rCBF), pial arterial diameter(PAD) and mean arterial blood pressure(MABP)] in normal and cerebral ischemic rats. The change of rCBF and MABP were determinated by laser-doppler flowmetry(LDF), and the change of PAD was determinated by video-microscopy. The results in normal rats were as follows ; PMT significantly increased rCBF and PAD in a dose-dependent, and PMT increased MABP in a dose-dependent. This results were suggested that PMT significantly increased rCBF by dilating PAD. The results in cerebral ischemic rats were as follows ; Both rCBF and PAD were significantly and stably increased by PMT(10㎎/㎏, i.p.) during the period of cerebral reperfusion, which contrasted with the findings of rapid and marked increase in control group. The present authors thought that PMT had an anti-ischemic effect through the improvement of cerebral hemodynamics.

• 대한한의학방제학회지
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• 제10권1호
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• pp.93-103
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• 2002

This experimental studies were done to investigate the effects of Sambutang(SBT) and consitituent herbs on the regional cerebral blood flow(rCBF) and mean arterial blood pressure(BP) in rats. The results are as follows: SBT and consitituent herbs(SBT omitting Zingiberis Rhizoma Recens, Zingiberis Rhizoma Recens. Ginseng Radix and Aconiti iateralis preparata Radix) was increased rCBF significantly in a dose-dependent manner. SBT omitting Zingiberis Rhizoma Recens and Ginseng Radix were decreased significantly BP in rats. But, SBT, Aconiti iateralis preparata Radix and Zingiberis Rhizoma Recens were not affected BP in rats. According to the above findings. it is suggested that SBT causes a diverse response of rCBF, and specially the rCBF by increasing SBT is mediated action of Zingiberis Rhizoma Recens.

• 동의생리병리학회지
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• 제21권6호
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• pp.1394-1400
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• 2007

This study was designed to investigate the effects of Samul-tang Extract and Bambusae caulis in liquamen(SEB) on the changes in regional cerebral blood flow (rCBF) and mean arterial blood pressure (MABP) in normal rats. The results were as follows ; SBE significantly increased rCBF in a dose-dependent manner, and increased MABP in a dose-dependent manner. This result suggests that SBE significantly increased rCBF by dilating pial arterial diameter. Increase of SBE-induced rCBF was significantly inhibited by pretreatment with indomethacin (1 mg/kg, i.p.), an inhibitor of cyclooxygenase and increase of SBE-induced rCBF was inhibited by pretreatment with methylene blue ($10\;{\mu}g/kg$, i.p.), an inhibitor of guanylate cyclase. Increase of SBE-induced MABP was significantly increased by pretreatment with methylene blue but increase of SBE-induced MABP was decreased by pretreatment with indomethacin. These results suggested that the action of SBE was mediated by cyclooxygenase.

• 대한한방내과학회지
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• 제23권1호
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• pp.33-39
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• 2002

Objective : The objective of this study is to measure the changes of regional cerebral blood flow(rCBF) and blood pressure(BP) in rats with the following injection. Methods : The measurement was continually monitored by laser-doppler flowmeter-Transonic Instrument, USA- and pressure tranducer(Grass, USA) in anesthetized adult Sprague-Dawley rats about for two hour to two hour and a half hours through the data acquisition system composed of Maclab and Macintosh computer. Result : This experiment with Samso-eum increased the changes of rCBF in rats, significantly, but did not change the blood pressure. The rCBF of Samso-eum decreased by pretreated propranolol, and was not changed by pretreated L-NNA and ODQ. Conclusion : It is considered that the dosage-dependent increase on rCBF is mediated by adrenegic ${\beta}$-receptor.

• 동의생리병리학회지
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• 제20권4호
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• pp.882-886
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• 2006

This study was designed to investigate the effects of Acanthopanax sessiliflorus 5.,M (ASS) on the regional cerebral blood flow (rCBF) and mean arterial blood pressure (BP) in normal rats and ischemic rats. Experimental groups of rCBF and BP in normal and ischemic rats as follows ; ALE was injected ASS leaves 45% ethyl alcohol extract, ASE was injected ASS stems 45% ethyl alcohol extract, ARE was injected ASS roots 45% ethyl alcohol extract. The results were as follows ; In normal rats, ALE and ARE significantly increased rCBF in a dose-dependent manner, but ASE significantly decreased rCBF and MABP in a dose-dependent manner, ALE increased MABP In ischemic rats, rCBF was significantly and staDly improved by ARE (10 mg/kg, i.p.) during the period of cerebral reperfusion, which was contrasted with the findings of rapid and marked increase in control group. From the above results, it was thought that all part of Acanthopanax sessiliflorus $S_{EEM}$ was effective for hemodynamics and especially ARE was more effective than other parts.

• 대한본초학회지
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• 제20권3호
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• pp.75-81
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• 2005

Objectives : In brain disorders such as ischemic stroke, the final outcome depends largely on the duration and the degree of the ischemia as well as the susceptibility of various cell types in the affected brain region. In the present study, the effects of Nodus Nelumbinis Rhizomatis Extract(NNRe) were tested for the anti-oxidative action of rCBF. Methods : Regional cerebral blood flow(rCBF) were determined by LDF methods. LDF allows for real time, noninvasive, continuous recordings of local CBF. The LDF method has been widely used to trace hemodynamic changes in the superficial or the deep brain structures in experimental stroke research. Results : NNRe treatment showed no change on rCBF in methylene blue, ODQ and L-NNA pretreated rats. 120 minutes of MCAO and followed reperfusion, 0.1% concentration of NNR treatment improved the altered cerebral hemodynamics of cerebral ischemic by increasing rCBF. Conclusions : The ischemia/reperfusion induced oxidative stress may have contributed to cerebral damage in rats, and the present study provides clear evidences for the beneficial effect of NNR on ischemia/reperfusion induced brain injury.