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The physiological characteristics of Pleurotus ferulae Lanzi (아위버섯균의 생리적 특성)

  • Kim, Dae-Sik;Chai, Jung-Ki;Wi, Kye-Moon;Yoon, Dai-Ryoung;Oh, Deuk-Sil;Chang, Kyoung Soo;Son, Han-Gil
    • Journal of Mushroom
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    • v.2 no.2
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    • pp.88-96
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    • 2004
  • This study was executed to decide the physiological characteristics of Ferule mushroom. Four strains of Ferule mushroom were tested to select a superior strain in its mycelial growth. The pertinent substrates, temperature and pH ranges for the growth of selected strain were determined. And then, the wood rotting ability and type of the Ferule mushroom were determined. The superior strain F-2 among four strains was selected, on the basis of its vegetative mycelial growth and density on agar media. Mycelial growth of F-2 was the best on MYPA among other tested synthetic or semi-synthetic media. The temperature range for pertinent mycelial growth was about $25{\sim}34^{\circ}C$ and best at $30^{\circ}C$. The optimum pH range on MYPA was 5.0~6.0. The mycelial growth was mostly stimulated by soluble starch at cont. 1% (w/w) and secondly, maltose among several carabon sources and by mixed solution of YE(0.25%) and ME(0.25%) but not by ME alone. Cell thining and erosion of Pinus rigida wood by the mycelia of Ferule mushroom were found only on a few cell but largely at wood block test, indicating that the softwood rotting ability of Ferule mushroom mycelia was not so good. The result of polarized light microscopy appeared that cellulose of some tracheides showing the S3 layer lost brifringence was degraded by Ferule mushroom. But only part of cellulose of P. rigida wood was degraded by Ferule mushroom, because most of wood cells continued to showing briefingence. A largely degraded ray parenchyma and longitudinal parenchyma cell and partly thinning and erosion of hardwood(Quercus serrata) cell was found and it indicates that the rotting ability of Ferule mushroom mycelia on hardwood was higher than on softwood. It could be concluded that the difference in the wood rot by Ferule mushroom between the hardwood and softwood was made by the difference of chemical constitutions between them, especially in the contents and the types of lignin. Ferule mushroom was considered as white rotter as a result of bavendam test, although more research should be required.

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Immunohistochemical Study to Evaluate the Prognostic Significance of Four Biomolecular Markers in Radiotherapy of Nasopharyngeal Carcinoma (방사선 치료를 받은 코인두암의 생체분자적 예후 인자를 찾기 위한 면역조직화학염색 연구)

  • Kim, Yeon-Joo;Lee, Seung-Hee;Wu, Hong-Gyun;Go, Heoun-Jeong;Jeon, Yoon-Kyung
    • Radiation Oncology Journal
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    • v.28 no.2
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    • pp.57-63
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    • 2010
  • Purpose: We performed an immunohistochemical study with pre-treatment biopsy specimens to evaluate the prognostic significance of four biomolecular markers which can be used as a predictive assay for radiotherapy (RT) treatment of nasopharyngeal carcinoma (NPC). Materials and Methods: From January 1998 through December 2006, 68 patients were histologically diagnosed as non-metastatic NPC and treated by RT. Only 38 patients had the paraffin block for the immunohistochemical study. Thirty-one patients had undifferentiated carcinoma and 7 patients had squamous cell carcinoma. Thirtytwo patients (84%) had advanced stage NPC (2002 AJCC Stage III~IV). Immunohistochemical staining was performed for Met, COX-2, nm23-H1, and epidermal growth factor receptor (EGFR) expression using routine methods. Results: The median follow-up time was 30 months (range, 11 to 83 months) for all patients, and 39 months (range, 19 to 83 months) for surviving patients. The 5-year overall survival (OS) rate of the patients with high Met extent (${\geq}50%$) was significantly lower than that of the patients with low Met extent (48% vs. 84%, p=0.02). In addition, Met extent was also a significant prognostic factor in multivariate analysis (p=0.01). No correlation was observed between Met extent and T stage, N stage, stage group, gender, age, and the response to chemotherapy or RT. Met extent showed moderate correlation with COX-2 expression (Pearson coefficient 0.496, p<0.01), but COX-2 expression did not affect OS. Neither nm23-H1 or EGFR expression was a prognostic factor for OS in this study. Conclusion: High Met extent (${\geq}50%$) might be an independent prognostic factor that predicts poor OS in NPC treated with RT.

Operative Treatment of Congenitally Corrected Transposition of the Great Arteries(CCTGA) (교정형 대혈관 전위증의 수술적 치료)

  • 이정렬;조광리;김용진;노준량;서결필
    • Journal of Chest Surgery
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    • v.32 no.7
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    • pp.621-627
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    • 1999
  • Background: Sixty five cases with congenitally corrected transposition of the great arteries (CCTGA) indicated for biventricular repair were operated on between 1984 and september 1998. Comparison between the results of the conventional(classic) connection(LV-PA) and the anatomic repair was done. Material and Method: Retrospective review was carried out based on the medical records of the patients. Operative procedures, complications and the long-term results accoding to the combining anomalies were analysed. Result: Mean age was 5.5$\pm$4.8 years(range, 2 months to 18years). Thirty nine were male and 26 were female. Situs solitus {S,L,L} was in 53 and situs inversus{I,D,D} in 12. There was no left ventricular outflow tract obstruction(LVOTO) in 13(20%) cases. The LVOTO was resulted from pulmonary stenosis(PS) in 26(40%)patients and from pulmonary atresia(PA) in 26(40%) patients. Twenty-five(38.5%) patients had tricuspid valve regurgitation(TR) greater than the mild degree that was present preoperatively. Twenty two patients previously underwent 24 systemic- pulmonary shunts previously. In the 13 patients without LVOTO, 7 simple closure of VSD or ASD, 3 tricuspid valve replacements(TVR), and 3 anatomic corrections(3 double switch operations: 1 Senning+ Rastelli, 1 Senning+REV-type, and 1 Senning+Arterial switch opera tion) were performed. As to the 26 patients with CCTGA+VSD or ASD+LVOTO(PS), 24 classic repairs and 2 double switch operations(1 Senning+Rastelli, 1 Mustard+REV-type) were done. In the 26 cases with CCTGA+VSD+LVOTO(PA), 19 classic repairs(18 Rastelli, 1 REV-type), and 7 double switch operations(7 Senning+Rastelli) were done. The degree of tricuspid regurgitation increased during the follow-up periods from 1.3$\pm$1.4 to 2.2$\pm$1.0 in the classic repair group(p<0.05), but not in the double switch group. Two patients had complete AV block preoperatively, and additional 7(10.8%) had newly developed complete AV block after the operation. Other complications were recurrent LVOTO(10), thromboembolism(4), persistent chest tube drainage over 2 weeks(4), chylothorax(3), bleeding(3), acute renal failure(2), and mediastinitis(2). Mean follow-up was 54$\pm$49 months(0-177 months). Thirteen patients died after the operation(operative mortality rate: 20.0%(13/65)), and there were 3 additional deaths during the follow up period(overall mortality: 24.6%(16/65)). The operative mortality in patients underwent anatomic repair was 33.3%(4/12). The actuarial survival rates at 1, 5, and 10 years were 75.0$\pm$5.6%, 75.0$\pm$5.6%, and 69.2$\pm$7.6%. Common causes of death were low cardiac output syndrome(8) and heart failure from TR(5). Conclusion: Although our study could not demonstrate the superiority of each classic or anatomic repair, we found that the anatomic repair has a merit of preventing the deterioration of tricuspid valve regurgitations. Meticulous selection of the patients and longer follow-up terms are mandatory to establish the selective advantages of both strategies.

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Survival and Complication Rate of Radiation Therapy in Stage I and II Carcinoma of Uterine Cervix (병기 I, II 자궁 경부암에서 방사선치료 후 생존율 및 합병증 분석)

  • Ma, Sun-Young;Cho, Heung-Lea;Sohn, Seung-Chang
    • Radiation Oncology Journal
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    • v.13 no.4
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    • pp.349-357
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    • 1995
  • Purpose : To analyze survival rate and late rectal and bladder complication for patients with stage I and II carcinoma of uterine cervix treated by radiation alone or combined with chemotherapy Materials and Methods : Between November 1984 and December 1993, 127 patients with stage I and II carcinoma of uterine cervix treated by radiation alone or combined therapy of radiation and chemotherapy. Retrospective analysis for survival rate was carried out on eligible 107 patients and review for complication was possible in 91 patients. The median follow-up was 47 months (range 3-118) and the median age of patiens was 56 years (range 31-76). 26 patients were stage IB by FIGO classification, 40 were stage IIA and 41 were stage IIB. 86 cases were treated by radiation alone and 21 were treated by radiation and chemotherapy. 101 patients were treated with intracavitary radiation therapy (ICRT), of these, 80 were received low dose rate (LDR) ICRT and 21 were received high dose rate (HDR) ICRT. Of the patients who received LDR ICRT, 63 were treated by 1 intracavitary insertion and 17 were underwent 2 insertions And we evaluated the external radiation dose and midline shield. Results : Actuarial survival rate at 5 years was $92{\%}$ for stage IB, $75{\%}$ for stage IIA, $53{\%}$ for stage IIB and $69{\%}$ in all patients Grade 1 rectal complications were developed in 20 cases ($22{\%}$), grade 2 were in 22 cases ($24{\%}$). 22 cases ($24{\%}$) of grade 1 urinary complications and 17 cases ($19{\%}$) of grade 2 urinary complications were observed But no patient had severe complications that needed surgical management or admission care. Maximum bladder dose for the group of patients with urinary complications was higher than that for the patients without urinary complications (7608 cGy v 6960cGy. p<0.01) Maximum rectal dose for the group of patients with rectal complications was higher than that for the patients without rectal complications (7041cGy v 6269cGy, p<0.01). While there was no significant difference for survival rate or bladder complication incidence as a function of dose to whole pelvis, Grade 2 rectal complication incidence was significantly lower for the patients receiving less than 4500cGy ($6.3{\%}$ v $25.5{\%}$, p<0.05). There was no significant differance between HDR ICRT group and LDR ICRT group for survival rate according to stage, on the other hand complication incidence was higher in the HDR group than LDR group, This was maybe due to different prescription doses between HDR group and LDR group. Midline shield neither improved survival rate nor decreased complication rate. The number of insertion in LDR ICRT group did not affect on survival and compication rate. Conclusion : In stage I and II carcinoma of uterine cervix there was no significant differance for 5 year survival rate by radiation therapy technique. Rectal complication incidence was as a function of dose to whole pelvis and there were positive correlations of maximum dose of rectum and bladder and each complication incidence. So we recommand whole pelvis dose less than 4500cGy and maximum dose of rectum and bladder as low as possible.

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Effect of ATP on Calcium Channel Modulation in Rat Adrenal Chromaffin Cells (흰쥐 부신 크로마핀 세포 칼슘통로 조절에 미치는 ATP의 효과)

  • Kim, Kyung Ah;Goo, Yong Sook
    • Progress in Medical Physics
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    • v.25 no.3
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    • pp.157-166
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    • 2014
  • ATP in quantity co-stored with neurotransmitters in the secretory vesicles of neurons, by being co-released with the neurotransmitters, takes an important role to modulate the stimulus-secretion response of neurotransmitters. Here, in this study, the modulatory effect of ATP was studied in $Ca^{2+}$ channels of cultured rat adrenal chromaffin cells to investigate the physiological role of ATP in neurons. The $Ca^{2+}$ channel current was recorded in a whole-cell patch clamp configuration, which was modulated by ATP. In 10 mM $Ba^{2+}$ bath solution, ATP treatment (0.1 mM) decreased the $Ba^{2+}$ current by an average of $36{\pm}6%$ (n=8), showing a dose-dependency within the range of $10^{-4}{\sim}10^{-1}mM$. The current was recovered by ATP washout, demonstrating its reversible pattern. This current blockade effect of ATP was disinhibited by a large prepulse up to +80 mV, since the $Ba^{2+}$ current increment was larger when treated with ATP ($37{\pm}5%$, n=11) compared to the control ($25{\pm}3%$, n=12, without ATP). The $Ba^{2+}$ current was recorded with $GTP{\gamma}S$, the non-hydrolyzable GTP analogue, to determine if the blocking effect of ATP was mediated by G-protein. The $Ba^{2+}$ current decreased down to 45% of control with $GTP{\gamma}S$. With a large prepulse (+80 mV), the current increment was $34{\pm}4%$ (n=19), which $25{\pm}3%$ (n=12) under control condition (without $GTP{\gamma}S$). The $Ba^{2+}$ current waveform was well fitted to a single-exponential curve for the control, while a double-exponential curve best fitted the current signal with ATP or $GTP{\gamma}S$. In other words, a slow activation component appeared with ATP or $GTP{\gamma}S$, which suggested that both ATP and $GTP{\gamma}S$ caused slower activation of $Ca^{2+}$ channels via the same mechanism. The results suggest that ATP may block the $Ca^{2+}$ channels by G-protein and this $Ca^{2+}$ channel blocking effect of ATP is important in autocrine (or paracrine) inhibition of adrenaline secretion in chromaffin cell.

Synergism Induced by Combination of Farnesyl Transferase Inhibitor SCH66336 and Insulin like-Growth Factor Binding Protein-3 in apoptosis of Non-Small Cell Lung Cancer Cell lines (비소세포성 폐암 세포주에서 Farnesyl Transferase Inhibitor SCH66336과 인슐린양 성장 인자 결합 단백-3의 병용처리에 의한 세포고사 상승 작용)

  • Kim, Young;Kim, Se Kyu;Kim, Hyung Jung;Chang, Joon;Ahn, Chul Min;Kim, Sung Kyu;Chang, Yoon Soo
    • Tuberculosis and Respiratory Diseases
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    • v.58 no.2
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    • pp.120-128
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    • 2005
  • Background : Insulin-like growth factor binding protein (IGFBP)-3 regulates non-small cell lung cancer(NSCLC) cell proliferation in vitro and in vivo by inhibiting IGF-mediated signaling pathways. To have better strategies for the treatment of lung cancer, we analyzed the combining effects of adenovirus expressing IGFBP-3 (Ad5CMV-BP3) and SCH66336, a farnesyl transferase inhibitor (FTI) designed to block Ras-mediated proliferative signaling pathways. Methods : To measure the combining effects of Ad5CMV-BP3 and SCH66336 on the proliferation of NSCLC cells, human NSCLC cell lines (H1299, H596, A549, H460, and H358), SCH66336, recombinant adenovirus expressing IGFBP-3 (Ad5CMV-BP3) and athymic nude mice were used in these experiments. Results : The combination of Ad5CMV-BP3 and SCH66336 produced a synergistic enhancement in antiproliferative effects over a range of clinically achievable concentrations in a variety of NSCLC cell lines. Furthermore, we observed a significant reduction in growth of NSCLC xenograft induced in athymic nude mice. Conclusion : In conclusion, this study demonstrated for the first time that the FTI SCH66336 synergizes with IGFBP-3 and enhances its apoptotic activity in NSCLC cells in vitro and in vivo. The combined treatment of Ad5CMV-BP3 and SCH66336 raises the possibility of using this regimen in clinic for the treatment of NSCLC.

Effects of Application Levels of Fermented Cattle Manure on Forage Yield, Quality and Soil Characteristics in Orchardgrass at Jeju Area (제주지역 오차드그라스 초지에서 톱밥발효우분퇴비 시용수준이 목초의 생산성, 사료가치 및 토양특성에 미치는 영향)

  • Hwang, Kyung-Jun;Park, Nam-Geon;Park, Hyung-Soo;Lee, Chong-Eon;Kim, Nam-Young;Ko, Moon-Suk;Kim, Moon-Chul;Song, Sang-Teak
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.30 no.2
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    • pp.127-134
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    • 2010
  • A study was conducted to determine the effects the of cattle manure application on forage yield, quality and soil in orchard grass pasture at the experimental field of Subtropical Animal Experiment Station, National Institute of Animal Science from 2008 to 2009. The experiment was arranged in a randomized complete block design with three replications. The treatment consisted of chemical fertilizer (CF N-200 kg/ha), cattle manure 50% (basis N, CM50%), CM100% (basis N), CM200% (basis N). The dry matter (DM) yield of CM200% was the highest among the other treatments. CF showed the highest average crude protein (CP) content by 12.4% and CM50% showed the lowest content by 11.0%. Average acid detergent fiber (ADF) and neutral detergent fiber (NDF) content were 30.4 and 69.7% respectively. All treatments have narrow range of total digestibility nutrient (TDN) from 64.0% to 69.1%. But there were big difference between treatment in forage nitrate content. Changes of physical and chemical properties of soils for applications of CF 200% and CM 200% was clearly in cattle manure application. Especially, CM application in pasture increased CF application with respect to soil pH, organic matter (OM), and avaliable phosphorous ($P_2O_5$) contents of soils.

The Influence of Landscape Pavements on the WBGT of Outdoor Spaces without Ventilation or Shade at Summer Midday (조경포장이 옥외공간의 온열쾌적성지수(WBGT)에 미치는 영향 - 통풍과 차광이 배제된 하절기 주간의 조건에서 -)

  • Lee, Chun-Seok;Ryu, Nam-Hyung
    • Journal of the Korean Institute of Landscape Architecture
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    • v.38 no.2
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    • pp.1-8
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    • 2010
  • The purpose of the study was to evaluate the influence of landscaping pavements on WBGT(Wet-Bulb Globe Temperature) of outdoor spaces that lack ventilation and shade at summer midday. The relative humidity(RH), dry-bulb temperature(DT) and globe temperature(GT) were recorded every minute from June to October 2009 at a height of 1.2m above ten experimental beds with different pavements, by a measuring system consisting of an electric humidity sensor(GHM-15), resistance temperature detector(RTD, Pt-100), standard black globe(${\phi} 150mm$) and data acquisition systems(National Instrument's Labview and Compact FieldPoint). Additionally, the surface dry-bulb temperatures also were recorded and compared. The area of each experimental bed was 1.5m(W)${\times}$2.0m(L) and ten different kinds of pavement were used including grass, grass+cubic stone, grass+porous brick, brick, stone panels, cubic stone, interlocking blocks, clay brick, naked soil, gravel and concrete. To prevent interference from ventilation, a 1.5m height cubic steel frame was established around each bed and each vertical side of the frame was covered with transparent polyethylene film. Based on the records of the hottest period from noon to 3 PM on 26 days with a peak dry-bulb temperature over $30^{\circ}C$ at natural condition, the wet-bulb temperature(WT) and WBGT were calculated and compared. The major findings were as follows: 1. The average surface DT was $40.1^{\circ}C$, which is $9^{\circ}C$ higher than that of the natural condition. The surface DT of the pavements with grass were higher than those of concrete and interlocking block. The peak DT of the surface almost every pavement rose to above $50^{\circ}C$ during the hottest time. 2. The averages of DT, WT and GT were $40.1^{\circ}C$, $27.5^{\circ}C$ and $49.1^{\circ}C$, and the peak values rose to $48.1^{\circ}C$, $45.8^{\circ}C$ and $59.5^{\circ}C$, respectively. In spite of slight differences that resulted according to pavements, no coherent differentiating factor could be found. 3. The average WBGT of grass was the highest at $34.3^{\circ}C$ while the others were similar in the range of around $33{\pm}1^{\circ}C$. Meanwhile, the peak WBGT was highest with stone panel at $47.9^{\circ}C$. Though there were some differences according to pavements, and while grass seemed to be worst in terms of WBGT, it seems difficult to say ablolutely that grass was the worst because the measurement was conducted without ventilation and shade during summer daytime hours only, which had temperatures that rose to a dangerous degree(above $45^{\circ}C$ WBGT), withering the grass during the hottest period. The average WBGT resulted also showed that the thermal environment of the pavement without ventilation and shade were at an intolerable level for humans regardless of the pavement type. In summary, the results of this study show that ventilation and shade are more important factor than pavement type in terms of outdoor thermal comfort in summer daylight hours.

Comparison of Forage Production and Feed Value of Winter Forage Crops in Jeju (제주지역에서 동계사료작물의 사초생산성 및 사료가치 비교)

  • Park, Hyung-Soo;Hwang, Kyung-Jun;Park, Nam-Geon;Choi, Gi-Jun;Lee, Jong-Kyung;Cheon, Dong-Won;Ko, Moon-Suck
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.28 no.3
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    • pp.215-220
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    • 2008
  • This experiment was conducted to compare forage production and feed value of winter forage crops at the experimental field of Livestock Division, National Institute of Subtropical Agriculture from 2007 to 2008. The experiment was arranged in a randomized block design with three replications. The five winter forage crops used in this experiment were barely ('Youngyang' and 'Yuyeon'), oats ('Samhan' and 'Swan'), wheat ('Kumkang' and 'Woori'), triticale ('Shinyoung') and italian ryegrass ('Hwasan 101' and 'Florida-80'). The species having the fastest heading date was wheat (5th April) while the heading date of oats ('Samhan') was the latest as 28th April. The dry matter (DM) content of wheat was the highest among the five winter forage crops. Italian ryegrass ('Hwasan 101') showed the highest CP content by 11.2% and oats (Swan) showed the lowest content by 9.8%. Average acid detergent fiber (ADF) and neutral detergent fiber (NDF) content were 28.6 and 50.8% respectively. The five winter forage crops have narrow range of total nutrient digestibility (TDN) from 64.0% to 69.1%. Italian ryegrass ('Hwasan 101') showed the highest DM yield by 25,951 kg/ha, but the DM yield of barely and wheat low by 13,892 kg/ha ('Yuyeon') and 14,815 kg/ha ('Woori'), respectively. Italian ryegrass and oats have higher forage yield and feed value in Jeju. Also, oats has high grain and forage yield. The results demonstrated oats can cultivate as alternative winter forage crop for whole crop silage barely in Jeju.

Effect of $Ca^{2+}$ and $Ca^{2+}-antagonists$ on the Spontaneous Contractions and Electrical Activities of Guinea-pig Stomach (기니피그 위 평활근의 자발적 수축과 전기적 활동에 대한 $Ca^{2+}$$Ca^{2+}$-길항제 영향)

  • Rhie, Sang-Ho;Kim, Ki-Whan
    • The Korean Journal of Physiology
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    • v.21 no.2
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    • pp.241-257
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    • 1987
  • The effects of external $Ca^{2+}$ and $Ca^{2+}-antagonists$ on the spontaneous contractions and electrical activities were investigated in guinea-pig stomach in order to clarify the mechanism for the generation of slow waves. Electrical responses of circular smooth muscle cells were recorded using glass capillary microelectrodes filled with 3 M KCl. All experiments were performed in tris-buffered Tyrode solution which was aerated with 100% $O_2$ and kept at $35^{\circ}C$. The results obtained were as follows: 1) The amplitude of spontaneous contractions was maximal at around 2-4 mM $Ca^{2+}$, whereas their frequency was inversely related with external $Ca^{2+}$ within the range of 0.5 to 16 mM $Ca^{2+}$. 2) Verapamil suppressed the amplitude of spontaneous contraction in a dose-dependent manner, while the frequency of spontaneous contractions was almost not changed over the whole concentration of verapamil $(0.01{\sim}5\;mg/l)$. 3) Manganese increased both the amplitude and the frequency of spontaneous contractions dose-dependently in low $Mn^{2+}$ (below 0.05 mM $Mn^{2+}$), while their amplitude and frequency were decreased in high $Mn^{2+}$ (above 0.1 mM $Mn^{2+}$). 4) The ampltude and maximum rate of rise of slow waves were incrased in high $Ca^{2+}$ solution. In $Ca^{2+}-free$ solution, the spontaneous contractions recorded simultaneously with slow waves ceased and tonic contraction ($Ca^{2+}-free$ contracture) was developed in parallel with membrane depolarization and the disappearance of slow waves. 5) Verapamil (1 mg/1) decreased the amplitude and maximum rate of rise of slow waves and it depolarized the membrane by about 6 mV, whereas the frequency of slow waves was not affected by verapamil. 6) Manganese showed different characteristic effects between low and high $Mn^{2+}$ on the slow waves: In low $Mn^{2+}$ (0.05 mM $Mn^{2+}$), the initial rapid increases and the subsequent gradual decreases in three parameters of slow waves (amplitude, rate of rise, and frequency of slow waves) till a new steady state were observed. However, in high $Mn^{2+}$ (0.5 mM $Mn^{2+}$) slow waves disappeared and membrane was depolarized. From the above results, the following conclusions could be made: 1) $Ca^{2+}$ is necessary for a generation of the slow waves, even though it is small amount. 2) Verapamil suppresses the spontaneous contractions of gastric antral strip by the decreases in amplitude and maximum rate of rise of slow waves, while this drug does not block the $Ca^{2+}-channel$ involved in the generation of slow waves. 3) Manganese has dual actions on the $Ca^{2+}-channels$; the $Ca^{2+}-channel$ involved in the generation of slow waves (or Na-Ca exchange system) or the channel for the generation of spike potentials are stimulated by a low concentration of $Mn^{2+}$, while both the $Ca^{2+}$. Channels are blocked by high concentration of $Mn^{2+}$.

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