• The Korean Journal of Physiology
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• 제30권1호
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• pp.105-116
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• 1996

Rendering the brain ischemic would evoke the cerebral ischemic reflex which is characterized by an arterial pressor response, apnea and bradycardia. Since the rostral ventrolateral medulla (RVLM) is known to play a key role in the maintenance of normal cardiopulmonary activity, during the cerebral ischemic reflex some cardiac related cells should be excited and respiration related cells inhibited. In this context, the responses of RVLM neurons to systemie and focal hypoxia were analyzed in the present study. Twenty-five adult cats of either sex were anesthetized with ${\alpha}-chloralose$ and the single neuronal activities were identified from RVLM area. For the induction of focal hypoxia in the recording site, sodium cyanide was applied iontophoretically and for systemic hypoxia the animal was ventilated with nitrogen gas for a twenty-second period. Cellular activities were analyzed in terms of their discharge pattern and responses to the hypoxia by using post-stimulus time and single-pass time histograms. Of eighteen cardiac related cells recorded from the RVLM area, twelve cells were excited by iontophoresed sodium cyanide and of twenty-five respiration related cells, fourteen cells were excited by iontophoresed sodium cyanide. Remaining cells were either inhibited or unaffected. Eight of fifteen cells tested with iontophoresed sodium lactate were excited and remaining seven cells were inhibited. Systemic hypoxia induced by nitrogen gas inhalation elevated the arterial blood pressure, but excited, inhibited or unaffected the single neuronal activities. Some cells showed initial excitation followed by inhibition during the systemic hypoxia. Bilateral vagotomy resulted in a decrease of arterial pressor response to the systemic hypoxia, and a slight decrease in the rhythmicity related to cardiac and/or respiratory rhythms. The single neuronal responses to either systemic or focal hypoxia were not affected qualitatively by vagotomy. From the above results, it was concluded that the majority of the cardiac- and respiration- related neurons in the rostral ventrolateral medulla be excited by hypoxia, not through the mediation of peripheral chemoreceptors, and along with the remaining inhibited cells, all these cells be involved in the mediation of cerebral ischemic reflex.

• Clinical and Experimental Pediatrics
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• 제51권1호
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• pp.93-97
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• 2008

갈색세포종은 부신 수질과 크롬친화성 조직에서 발생하는 소아기에는 드문 종양이다. 갈색세포종은 저산소증 상태와 연관이 있어, 단심실성 심장질환 수술 후에도 청색증이 지속되는 환자에서 병발하는 경우가 드물게 보고되고 있다. 갈색세포종의 증상이 애매할 뿐만 아니라 심장 질환 또는 치료 약제에 의하여 전형적인 증상들이 나타나지 않을 수 있다. 청색증형 선천성 심질환 환자에서 갑작스런 고혈압, 심장 상태의 악화, 또는 당뇨병 등을 포함한 애매한 증상들이 나타나는 경우에는 갈색세포종을 감별 진단하여야 한다. 저자들은 선천성 단심실성 심장질환과 갈색세포종이 동반된 2례를 보고한다.

• Korean Journal of Radiology
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• 제20권5호
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• pp.830-843
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• 2019

Objective: To examine the potential of intravoxel incoherent motion (IVIM) and blood oxygen level-dependent (BOLD) magnetic resonance imaging for detecting renal changes after iodinated contrast-induced acute kidney injury (CI-AKI) development in a diabetic rabbit model. Materials and Methods: Sixty-two rabbits were randomized into 2 groups: diabetic rabbits with the contrast agent (DCA) and healthy rabbits with the contrast agent (NCA). In each group, 6 rabbits underwent IVIM and BOLD imaging at 1 hour, 1 day, 2 days, 3 days, and 4 days after an iohexol injection while 5 rabbits were selected to undergo blood and histological examinations at these specific time points. Iohexol was administrated at a dose of 2.5 g I/kg of body weight. Further, the apparent transverse relaxation rate (R2^*), average pure molecular diffusion coefficient (D), pseudo-diffusion coefficient (D^*), perfusion fraction (f) were calculated. Results: The D and f values of the renal cortex (CO) and outer medulla (OM) were significantly decreased compared to baseline values in the 2 groups 1 day after the iohexol injection (p < 0.05). A marked reduction in the D^* values for both the CO and OM was also observed after 1 hour in each group (p < 0.05). In the OM, a persistent elevation of the R2^* was detected for 4 days in the DCA group (p < 0.05). Histopathological changes were prominent, and the pathological features of CI-AKI aggravated in the DCA group until day 4. The D, f, and R2^* values significantly correlated with the histological damage scores, hypoxia-inducible transcription factor-1α expression scores, and serum creatinine levels. Conclusion: A combination of IVIM and BOLD imaging may serve as a noninvasive method for detecting and monitoring CI-AKI in the early stages in the diabetic kidney.

• Investigative Magnetic Resonance Imaging
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• 제17권1호
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• pp.19-25
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• 2013

목적: 신장 혈중산소치의존 자기공명영상은 신장 산소공급의 평가로 사용되고 있다. 3T 자기공명영상에서 신장의 정상 $R2^*$ 값을 재고, 성별과 위치에 따른 $R2^*$ 값의 차이를 평가하고자 하였다. 대상과 방법: 24명의 건강한 자원자를 대상으로 3.0T 에서 혈중산소치의존 자기공명영상을 시행하였다. $T2^*$ 맵을 생성한 다음에 $R2^*$ 값을 계산하였고, 신피질과 신수질, 남녀 그리고 좌우 신장에 대한 $R2^*$값의 통계적 차이를 평가하였다. 양측 신장 내에서도 위치에 따른 $R2^*$값의 차이도 평가하였다. 결과: 모든 대상에서 혈중산소치의존 자기공명영상은 성공적이었으며, $R2^*$의 측정에 방해되는 인공물은 없었다. 3.0T에서의 평균 $R2^*$는 피질에서 $17.1{\pm}2.60s^{-1}$ 였으며 수질에서는 $27.7{\pm}4.83s^{-1}$ 였다 (p < 0.001). 남자의 수질의 $R2^*$ 값이 여자보다 통계적으로 유의하게 높았으나 (p=0.025), 좌우신이나 신장 내에서의 $R2^*$값의 통계적 차이는 없었다 (p=0.197). 결론: 3.0T에서 신장 혈중산소치의존 자기공명영상은 효과적으로 시행될 수 있었다. 정상인에서 상대적인 신수질의 저산소증이 존재하였고, 이 결과는 병리적인 환경에서 신장 평가에서의 기준치로 사용될 수 있을 것으로 생각된다.