• Archives of Reconstructive Microsurgery
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• 제3권1호
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• pp.40-44
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• 1994

Microsurgery has advanced beyond its nascent stages reaching success rates of 90% to 95%. However, this means that even in the best circumstances, 5% to 10% of free flaps and replants fail. Almost all failures are due to vessel thrombosis, resulting in ischemia of the transplanted tissue. Many attemps have been undertaken to treat and reverse its effects. Zdeblick and colleagues noted an improvement in the viability of amputated limbs replanted after an extended period of ischemia following intraarterial infusion of urokinase. Subsequent studies have investigated many modalities of urokinase administration in various animal models by differing ischemic periods. These studies, however, have failed to establish a definitive, generally accepted protocol for administration of urokinase in the salvage of tissue subjected to prolonged ischemia. Our clinical observations suggest that a bolus of urokinase delivered under pressure may increase the thromoblytic effect of the drug, probably by means of increased delivery to microvasculature. We intend to investigate the role of selective pressure perfusion of ischemic flaps as a new means for increasing the effectiveness of urokinase in the treatment of the "no-reflow" phenomenon. A total of 32 male New Zealand rabbits were used and divided into the four groups according to the method of infusion. After 12 hours of ischemia the flaps were injected with Hartmann's solution or with urokinase and the percent survival of the flap was determined at 7 days following flap reperfusion. As the result, the flap survival rate was highest in the pressure injection of urokinase group.

• 대한의용생체공학회:의공학회지
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• 제26권3호
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• pp.157-161
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• 2005

Direct injection of a fibrinolytic agent to the intraarterial thrombosis may increase the effectiveness of thrombolysis by enhancing the permeation of thrombolytic agents into the blood clot. Permeation of fibrinolytic agents into a clot is influenced by the surface pressure, which is determined by the injection velocity of fibrinolytic agents. In order to calculate the pressure distribution on the clot surface for different jet velocities (1, 3, 5 m/sec) and nozzle arrangements (1, 9, 17 nozzles), computational fluid dynamic methods were used. Thrombolysis of a clot was mathematically modeled based on the pressure and lysis front velocity relationship. Direct injection of a thrombolytic agent increased the speed of thrombolysis significantly and the effectiveness was increased as the ejecting velocity increased. The nine nozzles model showed about $20\%$ increase of the lysed volume, and the one and seventeen nozzles models did not show significant differences. The wall shear stress decreased as the number of nozzles increased, and the wall shear stress in most vessel wall was lower than 25 Pa. The results implied that thrombolysis could be accelerated by direct injection of a drug with the moderate velocity without damaging the blood vessel wall.

• The Korean Journal of Physiology
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• 제22권2호
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• pp.231-243
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• 1988

This study was performed to investigate the mechanism of changes in arterial blood pressure, as a typical example of somatosympathetic reflex, induced by activation of muscular afferent nerves. Cats were anesthetized with ${\alpha}-chloraloae$ (60 mg/kg, i.p.). Afferent fibers in muscle nerve were activated by various method muscle contraction, electrical stimulation of muscle nerves, intraarterial injection of some algesic substances and noxious mechanical stimulation etc-and the evoked changes in arterial blood pressure were monitored. The effects of intravenous or direct spinal administration of morphine on the changes in arterial blood pressure induced by activation of the muscle afferent fibers were observed and also the effects of spinal lesions made in the $L1{\sim}L3$ spinal cord on them were studied to identify the ascending spinal pathways of the somatosympathetic reflexes. Followings are the results obtained. 1) The stimulation of medial gastrocnemius nerve under non-paralyzed condition with C-strength, low frequency (lower than 20 Hz) stimuli elicited a depressor response and a pressor response was elicited with C-strength, high frequency stimuli, of which the maximal response was observed at 100 Hz stimulation. 2) When the animal was paralyzed, depressor response to stimulation of the medial gastrocnemius nerve was observed with C-strength, $0.5{\sim}5Hz$ stimuli although the amplitude of the depressor response was decreased. The maximal pressor response was observed during stimulation with C-strength, $20{\sim}100Hz$ stimuli. 3) Intraarterial injection of some algesic substances induced marked pressor responses while noxious mechanical stimulation of the medial gastrocnemius muscle was not enough to elicit any significant changes (larger than 10 mmHg) in arterial blood pressure. 4) Systemically administered morphine (2 mg/kg) lowered the arterial blood pressure immediately and persistently and it was reversed by administration of naloxone. Direct spinally administered morphine did not elicit any changes. 5) The pressor response elicited by the activation of muscle afferent nerves was strengthened by systemic morphine administration while the depressor response tended to decrease. 6) Morphine administered on the spinal cord directly, decreased pressor response but did not change depressor response. From the above results it is concluded that there are separate groups of afferent nerves in the medial gastrocnemius nerve, which elicit pressor and depressor responses and the spinal ascending pathways of them are also separated from each other.

• 대한약리학회지
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• 제31권2호
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• pp.251-259
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• 1995

Pharmacokinetics and pharmacodynamics of metoprolol, a selective beta-l blocker, were examined for 360 minutes after intravenous bolus administration of metoprolol to 6 dogs. Plasma concentration and excreted amount in the urine metoprolol were measured by liquid chromatography with fluorescence detection. PR interval and heart rate were measured by ECG monitoring. Blood pressure was monitored through intraarterial catheter in femoral artery and cardiac output by thermodilution method using Swan-Ganz catheter. To analyze the effect site concentration-response relationship, plasma concentration and pharmacological effects were simultaneously fitted to a two pharmacokinetic compartment linked to pharmacodynamic model with NONLIN program. Results are as follows. 1) The plasma concentration of metoprolol after intrvenous injection decreased biexponentially. The terminal half-life estimated was $1.33{\pm}0.40$ hours and the volume of distribution at steady state (Vdss) and the total body clearance were $1.04{\pm}0.4\;L/kg,\;6.55{\pm}2.21\;L/hr$, respectively. The central compartment volume of distribution and peripheral compartment volume of distribution were $0.35{\pm}0.14L/kg\;and\;0.69{\pm}0.34L/kg$. The renal clearance and intercompartment clearance were $0.53{\pm}0.25\;L/min\;and\;0.35{\pm}0.19\;L/min$. 2) Simulated biophase concentration-response curve shows hyperbolic relationship and the estimated concentration-effect relationship was best explained by Emax model when the prolongation of PR interval and the reduction of the heart rate were used as pharmacodynamic parameters. Emax and EC50 were estimated to be $26.3{\pm}4.7\;msec\;and\;88.8{\pm}82.3\;g/ml$ for PR interval, and $48.7{\pm}18.8\;beats/min\;and\;113.5{\pm}78.7\;ng/ml$ for heart rate, respectively. 3) The changes of cardiac output-effect site concentration relationship was best fitted by a linear model and the slope of the relationship was $0.005{\pm}0.003$. Diastolic blood pressure-effect site concentration relationship was also explained by the linear model and the slope of the relationship was $0.038{\pm}0.034$.

• 한국농림기상학회지
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• 제6권2호
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• pp.71-84
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• 2004

농업기상정보에 대한 수요는 흥미로운 내용보다는 농업현장에서 사용자가 직접 활용할 수 있는 내용이 점증하고 있다. 이러한 수요에 부응하기 위해서는 지역 또는 집단 별로 소속 농민을 위한 지역특성이 반영된 기후/기상 정보를 개발, 제공하여야 한다. 그리고 최종 사용자가 공식 기상기구에 의해 발표된 기상/기후 예보를 이해하는 데 도움을 줄 수 있는 도구가 제공되어야 한다. 특히 기본이 되는 근간자료를 포함하여 실시간 기상정보도 농민에게 함께 제공되어야 한다. 따라서 이상적인 농업기상정보시스템은 다음과 같은 요소를 포함하여야 한다. 1) 효율적인 자료 관측과 수집 체계, 2) 최신 통신시스템, 3) 표준 자료관리, 가공 및 분석 시스템, 및 4) 첨단 기술정보 배분시스템 등. 향후 인터넷이 농업기상정보 전달과 배분에 있어서 지속적으로 중요한 역할을 수행하겠지만 정보 풍요국과 빈곤국간의 격차는 날로 심화되어 갈 것이다. 그리고 농촌지역은 정보통로의 가장 끝자락을 의미하는데, 앞으로 많은 나라에서 정보통신 수단으로 TV, 라디오, 전화, 신문 및 팩스 등에 의존할 것으로 보이며, 정보와 배분 수단 확충에 필요한 가용 인적 및 경제적 자원에 따라 국가 간에 그 달성 여하에 차이가 있을 것이다. 이러한 차이점들은 농업기상 정보배분시스템 구축설계시에 반드시 고려되어야 한다. 과거 경험에 따르면, 사용자 요구에 적극 부응하는 정보들에 대한 손쉬운 접근을 통해서 기후정보의 활용이 근원적으로 증대한다는 것을 알 수 있다. 지리정보시스템과 원격탐사정보의 농업기상분야 적용도 향후 그 전망이 매우 밝은 분야라고 생각된다. 수 있을 것으로 사료된다. 유방병소를 수술전에 위치결정하는 방법은 그 수기가 간단하고도 안전하며 병소를 정확히 지시해 줌으로써 수술적 생검에 큰 도움을 주었고 그럼으로써 정상유방조직의 절제를 최소화하여 수술 후에 오는 유방의 외형상 변형을 최소화할 수 있었다. The blood pressure was dropped to 80/60 mmHg, but pulse rate was normal. She did not complain of dyspnea, and cyanosis was not developed. The urine volume was normally maintained. She was treated for pulmonary edema, which was completely absorbed after 20 hours. And the blood pressure was also normalized. We has experienced a case of pulmonary edema developed after intraarterial injection of the iodinated contrast medium without underlying cardiac, renal and hepatic problems, and reviewed the literatures on mechani 는 of pulmonary edema caused by intravascular injection of the iodinated contrast materials.석