작용시간 연장을 위해 고안된 이식형 혼합국소마취제의 효과

백운이,최병영,전영훈,임정옥 경북대학교 의학연구소 2000 경북대학교병원의학연구소논문집 Vol.4 No.1

Prolonged Regional Nerve Blockade from Implantable pellets Containing Mixture of Local Anesthetics and Biodegradable Polymer Background: The Currently available local anesthetics have limitations in action duration. The duration ranges from 3 to 8 hours. Long acting anesthetic agents are particularly desirable to manage postoperative pain, relieve severe pain associated with terminal cancer, and for nerve blocks carried out in pain clinics. In this paper mixture of local anesthetics was formulated into cylindrical pellet using biodegradable polymer and its efficacy and safety was evaluated. Methods: Pellets were prepared by modified melting process with biodegradable polyester 30 wt%, bupivacaine 35 wt%, lidocaine 35 wt% and dexamethasone 0.05 wt% of polymer and drug. In vitro release kinetics of local anesthetics from pellet were determined in PBS at pH 7.4. 37℃, and the released local anesthetics were analyzed by HPLC. Nine male Sprague Dawley weighing 300∼350 gm were implanted with pellets along the sciatic nerve and the sensory blockade was assessed by an analgesiometer. The duration data were analyzed by paired t-test using SAS 6.11 Results: Local anesthetics were released in a controlled manner in vitro. In general, 40~50% of the drug released for the first day, and thereafter approximately 5% released daily. Sensory blockade lasted to beyond 2 days at the dose of 7 mg/100 g bupivacaine and lidocaine respectively. All of the animals exhibited no systemic toxicity and complete recovery. Conclusions: The results indicated that the mixture pellet demonstrated efficient and safe in prolongation of sensory blockade for significant period of time. The mechanisms underlying the mixture effect are under investigation. (Korean J Anesthesiol 1998; 34; 493∼478)

적일積日

백이운(Baek Yi-Woon),신겸수(번역자) 고요아침 2013 시조시학 Vol.46 No.-

Succinylcholine chloride 정주시 가토 혈청 K^(+)와 Na^(+)치의 변동

백운이 慶北大學校 醫科大學 1986 慶北醫大雜誌 Vol.27 No.4

백서 척수강내 이식한 부신수질 크로마핀 세포의 진통 효과

백운이,임정옥,김유미,문철원,전영훈,한창규 대한마취과학회 2001 Korean Journal of Anesthesiology Vol.41 No.4

흡입마취제의 복합 투여시 흰쥐 노파스펙트럼의 변화

백운이 대한마취과학회 1996 Korean Journal of Anesthesiology Vol.31 No.3

Background: The electroencephalogram(EEG) has long been used to study the effects of anesthetic drugs on central nervous system function. This study was designed to evaluate the accuracy of two EEG parameters for assessing anesthetic depth during inhalation of 1.5 MAC three inhalation anesthetics (halothane, enflurane, and isoflurane) with 50%-N₂O in rats. Methods: Total 15 rats weighing between 300~350 g, with 5 rats for each anesthetic group were tested for investigation the anesthetic depth. EEG spectrum analysis was evaluated for three inhalation anesthetics which all were added with 50%-N₂O. The spectral edge frequency(SEF), median power frequency(MPF) were obtained from the EEG spectrum analysis of raw EEG via fast Fourier transform(FFT). Results: Raw EEG of halothare demonstrated sigmoidal shaped EEG, enflurane abundant spike waves, and isoflurane burst suppression. When 50%-N₂O was added to each anesthetic group, the characteristics of the raw EEG were disappeared. EEG spectrum analysis enabled to tinguish the effects of each anesthetic on the anesthetic depth. EEG spectrum analysis demonstrated after 50%-N₂O was added that the values of MPF and SEF were significantly decresed as 2.5 Hz and 6.5 Hz from 5.2 Hz and 14.2 Hz respectively. Conclusions: It is speculated that SEF and MPF was decreased due to the suppression of cerebral electrical activity. The decreases of SEF and MPF from analysis of EEG spectra confirm that the addition of 50%-N₂0 to each inhalation anesthetics enabled the deeper anesthetic depth.

작용시간 연장을 위해 고안된 이식형 혼합국소마취제의 효과

백운이,임정옥,최병영,전영훈 대한마취과학회 1998 Korean Journal of Anesthesiology Vol.34 No.3

Background: The currently available local anesthetics have limitations in action duration. The duration ranges from 3 to 8 hours. Long acting anesthetic agents are particularly desirable to manage postoperative pain, relieve severe pain associated with terminal cancer, and for nerve blocks carried out in pain clinics. In this paper mixture of local anesthetics was formulated into cylindrical pellet using biodegradable polymer and its efficacy and safety was evaluated. Methods : Pellets were prepared by modified melting process with biodegradable polyester 30 wt%, bupivacaine 35 wt%, lidocaine 35 wt% and dexamethasone 0.05 wt% of polymer and drug. In vitro release kinetics of local anesthetics from pellet were determined in PBS at pH 7.4, 37oC, and the released local anesthetics were analyzed by HPLC. Nine male Sprague Dawley weighing 300∼350 gm were implanted with pellets along the sciatic nerve and the sensory blockade was assessed by an analgesiometer. The duration data were analyzed by paired t-test usingSAS 6.11. Results : Local anesthetics were released in a controlled manner in vitro. In general, 40∼50% of the drug released for the first day, and thereafter approximately 5% released daily. Sensory blockade lasted to beyond 2 days at the dose of 7 mg/100 g bupivacaine and lidocaine respectively. All of the animals exhibited no systemic toxicity and complete recovery. Conclusions : The results indicated that the mixture pellet demonstrated efficient and safe in prolongation of sensory blockade for significant period of time. The mechanisms underlying the mixture effect are under investigation. (Korean J Anesthesiol 1998; 34: 493∼498)

제왕절개술중 정맥마취약제의 투여가 뇌파스펙트럼 분석에 미치는 영향

백운이,김시오,문철원 대한마취과학회 1996 Korean Journal of Anesthesiology Vol.31 No.3

Background: Anesthesia induces the spectral changes in EEG. Attempts to relate these spectral changes to adequacy of anesthesia have been hindered due to the complex waveforms of EEG. The objective of this investigation is to monitor the awareness of patients during cesarean section by means of EEG spectral analysis. Methods: 20 patients for cesarean section aged from 24 to 39 and ASA class I or II, were maintained with O₂(50%)-N₂O(50%)-enflurane(0.8%). And they were administered with midazolam(0.07 mg/kg) in group I(n=6), fentanyl(l ㎍/kg) in group II(n=7), and fentanyl(2 ㎍/kg) in group III(n=7) after birth. The density of each spectral band in EEG (delta 1-3.25 Hz, theta 3.5-7.75 Hz, alpha 8-12.15 Hz and beta 13-31.75Hz) was analyzed to derive total density, delta ratio and median power frequency. Results: The spectral data demonstrated that the alpha rhythm was dominant in pre-induction period and beta rhythm was abundant both in the immediate post-induction period and after birth for all three groupslta ratio and median power frequency decreased after injection of midazolam and fentanyl in all three groups. None of patients could reeall the memory about experience during cesarean section. Conclusions: These findings indicate that EEG spectral analysis is potentially useful to determine the changes of cerebroelectrical activity but difficult to monitor the awareness of patients during cesarean section.

Succinylcholine chloride 정주시 가토 혈청 K^+와 Na ^+치의 변동

백운이 慶北大學校 醫科大學 1986 慶北醫大誌 Vol.27 No.4

정상 가토에서 halothane군과 enflurane군에서 Sch을 정주하여(5㎎/㎏) 5분, 10분에 혈청 K^+치와 혈청 Na^+치를 측정하고, 첫번째 Sch투여후 20분에 Sch (5㎎/㎏)을 다시 투여후 5분만에 혈청 K^+치와 Na^+치를 측정해서 Sch투여전의 혈청 K^+치와 Na^+치와 비교관찰하여 다음의 결과를 얻었다. 혈청 K^+치의 변화는 halothane군에서는 5분, 25분에 의의있게 증가했으며(p<0.01), enflurane군에서도 5분, 10분, 25분에 모두 의의있게 증가했다(p<0.01). Halothane군과 enflurane군에서의 약제에 따른 혈청 K^+ 증가치는 유의한 차이가 없었다. 혈청 Na^+치의 변화는 두군데서 모두 유의한 변동이 없었다. Succinylcholine (5㎎/㎏) were given to rabbits under general anesthesia by O_2-N_2O-Halothane or O_2-N_2O-Enflurane through tracheotomy tube to assess serum K^+, Na^+ changes in each group. The followings are the results we obtained. Serum K^+ significantly increases after 5 minutes, 25 minutes (p<0.01)following administration of succinylcholine but increasing after 10 minutes is not significant in halothane anesthesia. Serum K^+ significantly increases in 5, 10, 25 minutes (p<0.01) following administration of succinylcholine in enflurane anesthesia. There are no significant changes in serum Na^+ following administration of succinylcholine in both group. There are no differences between halothane and enflurane anesthesia in serum K^+ and Na^+ changes following administration of succinylcholine.

Analysis of topological properties in a seismic network

Baek, Woon Hak,Lim, Gyuchang,Kim, Kyungsik,Choi, Young-Jean,Chang, Ki-Ho,Jung, Jae-Won,Yi, Myunggi,Lee, Dong-In,Ha, Deok-Ho Elsevier 2012 PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIO Vol.391 No.6

<P><B>Abstract</B></P><P>In this study, we examine a seismic network by considering the cell resolution and the temporal causality. Seismic activity data from the Korean peninsula are mapped onto a growing network with links between consecutive events. After we especially show a seismic network with spatial heterogeneity and scales in an area, topological properties of this seismic activity network are measured and found. Our result for the robustness of these properties can be compared with other calculated findings.</P> <P><B>Highlights</B></P><P>► We study a seismic network by considering the cell resolution and the temporal causality. ► A computer simulation of the seismic network is performed using seismic time series data. ► We mainly estimate the global network metrics from seismic data of the Korean peninsula.</P>

체외순환을 위한 냉각과 재가온시 이산화탄소가스의 첨가에 따른 체온변화

백운이,김시오,손현호,도건호 대한마취과학회 1998 Korean Journal of Anesthesiology Vol.35 No.5

Background : It is well known that the addition of CO2 gas during cardiopulmonary bypass (CPB) can increase cerebral blood flow (CBF). In this study, we tried to find whether the increase of CBF by CO2 gas could be expressed on the measurement of body temperatures. Methods : This study included 22 adult patients who underwent CPB with moderate hypothermia and were assigned randomly to two groups by adding CO2 gas (CO2 group and Air group). We measured each tympanic (TM), nasopharyngeal (NP), oral, forehead, finger, rectal and CPB arterial line temperatures of CPB circuit for 20 times during cooling in every one minute for 20 minutes and during rewarming every two minutes for 40 minutes. Results : During cooling and rewarming, the TM, NP and oral temperatures changed more rapidly than the rectal and finger temperatures. In TM temperature, as time changed, the percent changes of temperature varied more prominently in the CO2 gas group than in the Air group. The statistical differences were significant especially during 13 minutes to 20 minutes in cooling and 8 minutes to 20 minutes during rewarming. Conclusion : From this data, we can postulate the effect of CO2 gas on CBF indirectly by measuring several sites of body temperatures. (Korean J Anesthesiol 1998; 35: 958∼964)