• Title/Summary/Keyword: Function Material

Search Result 4,113, Processing Time 0.03 seconds

The Pattern of Initial Displacement in Lingual Lever Arm Traction of 6 Maxillary Anterior Teeth According to Different Material Properties: 3-D FEA (유한요소모델에서 레버암을 이용한 상악 6전치 설측 견인 시 초기 이동 양상)

  • Choi, In-Ho;Cha, Kyung-Suk;Chung, Dong-Hwa
    • Journal of Dental Rehabilitation and Applied Science
    • /
    • v.24 no.2
    • /
    • pp.213-230
    • /
    • 2008
  • The aim of this study was to analyze the initial movement and the stress distribution of each tooth and periodontal ligament during the lingual lever-arm retraction of 6 maxillary incisors using FEA. Two kinds of finite element models were produced: 2-properties model (simple model) and 24-properties model (multi model) according to the material property assignment. The subject was an adult male of 23 years old. The DICOM images through the CT of the patient were converted into the 3D image model of a skull using the Mimics (version 10.11, Materialise's interactive Medical Image Control System, Materialise, Belgium). After series of calculating, remeshing, exporting, importing process and volume mesh process was performed, FEA models were produced. FEA models are consisted of maxilla, maxillary central incisor, lateral incisor, canine, periodontal ligaments and lingual traction arm. The boundary conditions fixed the movements of posterior, sagittal and upper part of the model to the directions of X, Y, Z axis respectively. The model was set to be symmetrical to X axis. Through the center of resistance of maxilla complex, a retraction force of 200g was applied horizontally to the occlusal plane. Under this conditions, the initial movements and stress distributions were evaluated by 3D FEA. In the result, the amount of posterior movement was larger in the multi model than in the simple model as well as the amount of vertically rotation. The pattern of the posterior movement in the central incisors and lateral incisors was controlled tipping movement, and the amount was larger than in the canine. But the amount of root movement of the canine was larger than others. The incisor rotated downwardly and the canines upwardly around contact points of lateral incisor and canine in the both models. The values of stress are similar in the both simple and multi model.

Study on the State Leadership's Safety Measures Regarding the North Korean Threat of Weapons of Mass Destruction - Focuses on the Threat of North Korean Nuclear Weapons (북한 대량살상무기 위협에 대한 국가지도부 안전대책에 관한 연구 - 북한 핵무기 위협을 중심으로)

  • Choi, Kee-Nam
    • Korean Security Journal
    • /
    • no.37
    • /
    • pp.325-354
    • /
    • 2013
  • The concept of national security and the fundamental system for crisis management have departed from traditional methods and the importance of a national critical infrastructure crisis management has been emphasized. A national critical infrastructure crisis means a situation where human resource, material and functional system that may have a material effect on the critical functions of the government, the vitality and integrity of society, national economy and the safety of the public becomes disabled due to causes such as terrorism or major disasters. Although North Korea had been subject to numerous rounds of negotiations and sanctions as it continually developed nuclear weapons since the 1960s, it has also showed off its nuclear armaments through successful nuclear testings and missile launches. As the development and threat of North Korea's weapons of mass destruction becomes more noticeable and the range of its risk expands, this study focuses on the potential for an absence of leadership for national crisis management where the country's leadership, which should serve the critical role and function of handling national crises, becomes completely destroyed by the unexpected initial attacks by North Korea. As a result, the purpose of this study is to propose safety measures for the country's leadership in preparation for North Korea's threat of nuclear weapons by examining the concept and degree of risk of weapons of mass destruction with a focus on nuclear weapons, analyzing the substance of the threat of North Korean nuclear weapons and evaluating such threat. In conclusion, first, to ensure the normal functioning of a national crisis management system in the event of a national crisis, we must seek safety measures that conform to the scope and succession order of the leadership of the national crisis management for an Enduring Constitutional Government (ECG) and the Continuity Of Operations (COOP). Second, in the event of a national ceremony, the gathering of the country's leadership all together in an open place should be avoided. In unavoidable circumstances, the next in rank that will act on behalf of the current leader should be designated and relevant safety measures should be taken. Third, during time of peace, in preparation for national crises, the scope of protection for the country's leadership should be prescribed and specific security and safety measures should be implemented. Fourth, the succession order for acting president in the case of the death of the president pursuant to Articles 71 and 26(1) of the National Government Organization Act should reconsidered to see whether it is a reasonable provision that takes into consideration a national crisis management that corresponds to the threat of North Korean nuclear weapons and weapons of mass destruction. Pursuant to the Basic Guidelines for National Crisis Management set out under Presidential Directive No. 229, the Korean government is currently operating a case-by-case "crisis management standard manual" and its sub-manuals and has also prepared the Presidential Security Service's security and safety measure regulations regarding the acting president. Therefore, the Korean government should actualize the above points in the case-by-case crisis management standard manual and security and safety measure regulations regarding the acting president to implement and legislate them.

  • PDF

Attitudes and Problems of Urban Parks, in Taegu City, Korea (도시공원(都市公園)의 속성(屬性)과 문제점(問題點))

  • Choi, Seok-Joo
    • Journal of the Korean association of regional geographers
    • /
    • v.2 no.2
    • /
    • pp.205-217
    • /
    • 1996
  • Today in the industrial society, the urban park is the place for citizens' health, recreation, exercise, and education. This is a very important place as a fine sight and maintenance of public security. As the results of rapid economic growth during the last thirty years, citizens are in the age of material civilization and are challenged with many serious urban problems such as pollution, noise, traffic congestion, human alienation, etc. Rapid material civilization brought to citizens' mental and physical diseases. To some of the problems, it is necessary that we should have proper leisure and recreation facilities, and that we should have the active, positive posture to them. Especially we need the out door recreational spaces and facilities. But nowadays the urban parks are given little thought in spites of the necessity of parks which should be used as a recreational spaces in the urban areas. So, This study attempt to comprehend the function, quantity and quality of the urban park system in Taegu. It is clear that the quantity is inappropriate. Because of inappropriate disposition and management, its coefficiency of utilization is low. In view of the population and park ratio, Dong Gu, Nam Gu, Suseong Gu and Dalseong Gun have comparative good, environments. However, Dalseo Qu, Seo Gu and Jung Gu have less geographical features. There are some methods to provide expansion of the aggregate of urban parks. We can use the school-grounds and their facilities. which were moved from C.B.D. to the outskirts of Daegu, or some parts of urban redevelopment, or the riverside of Sincheon river. In the urban park-program, users' satisfaction-factors are analyzed. We must reconsider the efficiency. The above problems are improved. Active administration and inhabitants' Positive participation are demanded so that the sound development of cities and daily life-surroundings are promoted.

  • PDF

The Effect of Safflower Seed Extract on the Bone Formation of Calvarial Bone Model in Sprague Dawley rat (백서 두개골 결손부에서 홍화씨 추출물의 골조직 재생 유도 효과)

  • Kim, Sung-Tae;Jhon, Gil-Ja;Lim, So-Hyoung;Cho, Kyoo-Sung;Kim, Chong-Kwan;Choi, Seong-Ho
    • Journal of Periodontal and Implant Science
    • /
    • v.30 no.4
    • /
    • pp.835-852
    • /
    • 2000
  • The ultimate goal of periodontal therapy is the regeneration of periodontal tissue and repair of function. For more than a decade there have been many efforts to develop materials and methods of treatment to promote periodontal wound healing. Recently many efforts are concentrated on the regeneration potential of material used in oriental medicine. In some in vitro and in vivo experiments, there have been many evidences that these materials have an effect on bone regeneration. The purpose of this study was to evaluate histologically and radiologically in Sprague-Dawley rats the effects of safflower seed extracts on the regeneration of the calvarial defects surgically produced. So in this study, the critical size defects were surgically produced in the calvarial bone of 30 Sprague-Dawley rats using the 8mm trephine bur. The safflower seed extract was applied into the defect of each rat in experimental group, whereas nothing was applied into the defect of each rat in control group. Rats were sacrificed at 2, 4, 8 weeks following operation and histomorphometric and radiodensitometric analysis were performed. 1. The newly formed bone length was $102.91{\pm}22.05$, $178.29{\pm}24.40$ at 2 week in the each control, experimental group, $130.95{\pm}39.24$, $242.62{\pm}50.33$ at 4 week and $181.53{\pm}76.35$, $240.36{\pm}22.00$ at 8 week($unit,{\mu}m$). In the 2, 4 week, there were statistically significant difference between control and experimental group(P<0.05). 2. The newly formed bone area was $2962.06{\pm}1284.48$, $10648.35{\pm}1284.48$ at 2 week, $5103.25{\pm}1375.88$, $9706.78{\pm}1481.81$ at 4 week, $8046.02{\pm}818.99$, $12057.06{\pm}740.47$ at 8 week($unit,{\mu}m^2$). In every week, there were statistically significant difference between control and experimental group(P<0.05). 3. The radiopacity was $14.26{\pm}.33$, $25.47{\pm}4.33$ at 2 week, $20.06{\pm}9.07$, $26.61{\pm}2.78$ at 4 week, $22.99{\pm}3.76$, $27.29{\pm}1.54$ at 8 week(unit, %). In the 2 week, there was statistically significant difference between control and experimental group(P<0.05). In conclusion, the results of the present study suggest that safflower seed extract initially has an effect on the newly formed bone area, length and radiopacity when it is applied to the calvarial defect of Sprague - Dawley rat. Then. the material has an effect on newly formed bone area and length.

  • PDF

A research on the introducing the waterproof corrugated cardboard box for the efficient shipment of chinese cabbages and radishes: Focusing on Garak-dong wholesale market as the center

  • Lee, Rae-Hyup;Sun, Il-Suck
    • Asian Journal of Business Environment
    • /
    • v.2 no.1
    • /
    • pp.25-34
    • /
    • 2012
  • It is possible to use pallet for forwarding as chinese cabbages and radishes are general large-scale trading items at the agricultural wholesale market though, however, most of these are forwarded as it have packed in net bags or in P·E bags. Thus, it is still hard for palletizing. The type of packing the product in the net bag makes it difficult for palletizing. It is not a stable shape enough and easily collapsed for pallet loading. Because of this collapsibility, the corrugated cardboard box is being used to enhance forwarding efficiency, but the existing corrugated cardboard box could be crushed easily by moist what is from the agricultural product's property and it also could be squashed by the mass of the loaded box layers on itself. In contrary, the functional waterproof corrugated cardboard box is not collapsed through palletizing and it is efficient for product management with it's ventilation function in respond to pre-cooling effect. Furthermore, because it has various functional shapes as the open type, the partition type and so on, it is effective for maintaining freshness of the product and standardizing the distribution of agricultural product. It is well-known that it is possible to introduce this box to cargo-works of agricultural product. Consequently, the recognition of main distributors about the pallet distribution of the chinese cabbage and the radish was apprehended in this study for activating mechanization of loading and unloading. The survey was conducted to the main distributors such as the forwarder, the auction dealer and the commission merchant with Garak-dong wholesale market as the center. The appropriate packing materials and problems of the existing method for loading and unloading were derived through the survey. Especially, it was focused on analyzing the difference of recognition between the subject groups for the way of using waterproof cardboard corrugated box to deal with the difficult product for packing in normal corrugated box because of the box's absorption of moist from the agricultural product like a chinese cabbage and a radish. Total In the cases of the forwarders and the commission merchants, the net was highly responded as 45%, 74% from each groups for the best packing material for mechanization of distribution and the waterproof corrugated cardboard box was responded as 20%, 22% from each groups as much preferable than multi-stage wooden box. However, for the radish, the waterproof corrugated cardboard box was the best material as 56%, and the auction trader group supported it for 80%. So, the using the waterproof corrugated cardboard box for mechanization of distribution was negative for the chinese cabbage, but it was positive for the radish. The average was 2.42, the standard deviation was 1.24. The negative response(about 55%) was prevailing more than positive response(about 23%). It could be analyzed that even there was the positive recognition for using the waterproof corrugated cardboard box for the radish though the preference for low price of net bag in the chinese cabbage forwarding procedure. Still now, it seems that is a burden for using the waterproof corrugated cardboard box with high price. In the analysis on the recognition differences about using the waterproof corrugated cardboard box for the chinese cabbages and the radish between the forwarders and the commission merchants, generally the negative recognition was prevailing, but the forwarders(2.696) were more positive for using the waterproof corrugated cardboard box than the commission merchants(2.145).

  • PDF

Study on skin anti-inflammatory activity of fig (Ficus carica L.) fruit extract fractions (무화과(Ficus carica L.) 열매 추출 분획의 피부 항염증 활성 연구)

  • Hee Joon Kwon;Geun soo Lee;Jin Hwa Kim;Soon Woo Kwon;Hyung seo Hwang
    • Journal of Applied Biological Chemistry
    • /
    • v.66
    • /
    • pp.416-423
    • /
    • 2023
  • Figs has known to have antioxidant, whitening, anti-inflammatory, and antibacterial effects in their leaves, roots, stems, latex, and fruits. In order to develop cosmetic materials based on natural products, we have studied on the skin activity of the ficin in latex as well as the whitening function of the fruit extract with 70% ethanol, and used it as a raw material for released cosmetic product. However, there is little research on the demand for the development of new eutectic solvent extraction methods and its ability to control skin inflammation and psoriasis regulation. Thus, in this study, we evaluated the effectiveness of fig fruit extracts and fractions using eutectic solvent extraction for skin inflammation control and psoriasis. First, fig fruits were extracted under optimal eutectic solvent conditions and fractionated with n-hexane, dichloromethane, ethyl acetate, and butanol. First, the antioxidant activity and inhibition of nitric oxide (NO) production were confirmed in mouse macrophage RAW264.7 cells. In addition, as a result of observing the mRNA expression through RT-PCR, pro-inflammatory cytokines such as TNF-α, IL1α, and IL-1β were suppressed significantly in the hexane, dichloromethane, and ethyl acetate fractions. In addition, it was confirmed in TNF-α stimulated HaCaT keratinocyte model. Finally, chemokine CC motif ligand 20 (CCL20), marker gene of human psoriasis skin disease, was significantly suppressed in the hexane, dichloromethane, and ethyl acetate fractions. These results suggested its anti-inflammatory and skin soothing effect and the possibility of development as an excellent skin soothing natural cosmetic material in the future through future clinical trials.

The hydrodynamic characteristics of the canvas kite - 2. The characteristics of the triangular canvas kite - (캔버스 카이트의 유체역학적 특성에 관한 연구 - 2. 삼각형 캔버스 카이트의 특성 -)

  • Bae, Bong-Seong;Bae, Jae-Hyun;An, Heui-Chun;Lee, Ju-Hee;Shin, Jung-Wook
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.40 no.3
    • /
    • pp.206-213
    • /
    • 2004
  • As far as an opening device of fishing gears is concerned, applications of a kite are under development around the world. The typical examples are found in the opening device of the stow net on anchor and the buoyancy material of the trawl. While the stow net on anchor has proved its capability for the past 20 years, the trawl has not been wildly used since it has been first introduced for the commercial use only without sufficient studies and thus has revealed many drawbacks. Therefore, the fundamental hydrodynamics of the kite itself need to ne studied further. Models of plate and canvas kite were deployed in the circulating water tank for the mechanical test. For this situation lift and drag tests were performed considering a change in the shape of objects, which resulted in a different aspect ratio of rectangle and trapezoid. The results obtained from the above approaches are summarized as follows, where aspect ratio, attack angle, lift coefficient and maximum lift coefficient are denoted as A, B, $C_L$ and $C_{Lmax}$ respectively : 1. Given the triangular plate, $C_{Lmax}$ was produced as 1.26${\sim}$1.32 with A${\leq}$1 and 38$^{\circ}$B${\leq}$42$^{\circ}$. And when A${\geq}$1.5 and 20$^{\circ}$${\leq}$B${\leq}$50$^{\circ}$, $C_L$ was around 0.85. Given the inverted triangular plate, $C_{Lmax}$ was 1.46${\sim}$1.56 with A${\leq}$1 and 36$^{\circ}$B${\leq}$38$^{\circ}$. And When A${\geq}$1.5 and 22$^{\circ}$B${\leq}$26$^{\circ}$, $C_{Lmax}$ was 1.05${\sim}$1.21. Given the triangular kite, $C_{Lmax}$ was produced as 1.67${\sim}$1.77 with A${\leq}$1 and 46$^{\circ}$B${\leq}$48$^{\circ}$. And when A${\geq}$1.5 and 20$^{\circ}$B${\leq}$50$^{\circ}$, $C_L$ was around 1.10. Given the inverted triangular kite, $C_{Lmax}$ was 1.44${\sim}$1.68 with A${\leq}$1 and 28$^{\circ}$B${\leq}$32$^{\circ}$. And when A${\geq}$1.5 and 18$^{\circ}$B${\leq}$24$^{\circ}$, $C_{Lmax}$ was 1.03${\sim}$1.18. 2. For a model with A=1/2, an increase in B caused an increase in $C_L$ until $C_L$ has reached the maximum. Then there was a tendency of a very gradual decrease or no change in the value of $C_L$. For a model with A=2/3, the tendency of $C_L$ was similar to the case of a model with A=1/2. For a model with A=1, an increase in B caused an increase in $C_L$ until $C_L$ has reached the maximum. And the tendency of $C_L$ didn't change dramatically. For a model with A=1.5, the tendency of $C_L$ as a function of B was changed very small as 0.75${\sim}$1.22 with 20$^{\circ}$B${\leq}$50$^{\circ}$. For a model with A=2, the tendency of $C_L$ as a function of B was almost the same in the triangular model. There was no considerable change in the models with 20$^{\circ}$B${\leq}$50$^{\circ}$. 3. The inverted model's $C_L$ as a function of increase of B reached the maximum rapidly, then decreased gradually compared to the non-inverted models. Others were decreased dramatically. 4. The action point of dynamic pressure in accordance with the attack angle was close to the rear area of the model with small attack angle, and with large attack angle, the action point was close to the front part of the model. 5. There was camber vertex in the position in which the fluid pressure was generated, and the triangular canvas had large value of camber vertex when the aspect ratio was high, while the inverted triangular canvas was versa. 6. All canvas kite had larger camber ratio when the aspect ratio was high, and the triangular canvas had larger one when the attack angle was high, while the inverted triangluar canvas was versa.

Study on the Short-Term Hemodynamic Effects of Experimental Cardiomyoplasty in Heart Failure Model (심부전 모델에서 실험적 심근성형술의 단기 혈역학적 효과에 관한 연구)

  • Jeong, Yoon-Seop;Youm, Wook;Lee, Chang-Ha;Kim, Wook-Seong;Lee, Young-Tak;Kim, Won-Gon
    • Journal of Chest Surgery
    • /
    • v.32 no.3
    • /
    • pp.224-236
    • /
    • 1999
  • Background: To evaluate the short-term effect of dynamic cardiomyoplasty on circulatory function and detect the related factors that can affect it, experimental cardiomyoplasties were performed under the state of normal cardiac function and heart failure. Material and Method: A total of 10 mongrel dogs weighing 20 to 30kg were divided arbitrarily into two groups. Five dogs of group A underwent cardiomyoplasty with latissimus dorsi(LD) muscle mobilization followed by a 2-week vascular delay and 6-week muscle training. Then, hemodynamic studies were conducted. In group B, doxorubicin was given to 5 dogs in an IV dose of 1 mg/kg once a week for 8 weeks to induce chronic heart failure, and simultaneous muscle training was given for preconditioning during this period. Then, cardiomyoplasties were performed and hemodynamic studies were conducted immediately after these cardiomyoplasties in group B. Result: In group A, under the state of normal cardiac function, only mean right atrial pressure significantly increased with the pacer-on(p<0.05) and the left ventricular hemodynamic parameters did not change significantly. However, with pacer-on in group B, cardiac output(CO), rate of left ventricular pressure development(dp/dt), stroke volume(SV), and left ventricular stroke work(SW) increased by 16.7${\pm}$7.2%, 9.3${\pm}$3.2%, 16.8${\pm}$8.6%, and 23.1${\pm}$9.7%, respectively, whereas left ventricular end-diastole pressure(LVEDP) and mean pulmonary capillary wedge pressure(mPCWP) decreased by 32.1${\pm}$4.6% and 17.7${\pm}$9.1%, respectively(p<0.05). In group A, imipramine was infused at the rate of 7.5mg/kg/hour for 34${\pm}$2.6 minutes to induce acute heart failure, which resulted in the reduction of cardiac output by 17.5${\pm}$2.7%, systolic left ventricular pressure by 15.8${\pm}$2.5% and the elevation of left ventricular end-diastole pressure by 54.3${\pm}$15.2%(p<0.05). With pacer-on under this state of acute heart failu e, CO, dp/dt, SV, and SW increased by 4.5${\pm}$1.8% and 3.1${\pm}$1.1%, 5.7${\pm}$3.6%, and 6.9${\pm}$4.4%, respectively, whereas LVEDP decreased by 11.7${\pm}$4.7%(p<0.05). Comparing CO, dp/dt, SV, SW and LVEDP that changed significantly with pacer-on, both under the state of acute and chronic heart failure, augmentation widths of these left ventricular hemodynamic parameters were significantly larger under the state of chronic heart failure(group B) than acute heart failure(group A)(p<0.05). On gross inspection, variable degrees of adhesion and inflammation were present in all 5 dogs of group A, including 2 dogs that showed no muscle contraction. No adhesion and inflammation were, however, present in all 5 dogs of group B, which showed vivid muscle contractions. Considering these differences in gross findings along with the following premise that the acute heart failure state was not statistically different from the chronic one in terms of left ventricular parameters(p>0.05), the larger augmentation effect seen in group B is presumed to be mainly attributed to the viability and contractility of the LD muscle. Conclusion: These results indicate that the positive circulatory augmentation effect of cardiomyoplasty is apparent only under the state of heart failure and the preservation of muscle contractility is important to maximize this effect.

  • PDF

Cardioprotective Effect of Calcium Preconditioning and Its Relation to Protein Kinase C in Isolated Perfused Rabbit Heart (적출관류 토끼 심장에서 칼슘 전처치에 의한 심근보호 효과와 Protein Kinase C와의 관계)

  • 김용한;손동섭;조대윤;양기민;김호덕
    • Journal of Chest Surgery
    • /
    • v.32 no.7
    • /
    • pp.603-612
    • /
    • 1999
  • Background : It has been documented that brief repetitive periods of ischemia and reperfusion (ischemic preconditioning, IP) enhances the recovery of post-ischemic contractile function and reduces infarct size after a longer period of ischemia. Many mechanisms have been proposed to explain this process. Recent studies have suggested that transient increase in the intracellular calcium may have triggered the activation of protein kinase C(PKC); however, there are still many controversies. Accordingly, the author performed the present study to test the hypothesis that preconditioning with high concentration of calcium before sustained subsequent ischemia(calcium preconditioning) mimics IP by PKC activation. Material and Method : The isolated hearts from the New Zealand White rabbits(1.5∼2.0 kg body weight) Method: The isolated hearts from the New Zealand White rabbits(1.5∼2.0 kg body weight) were perfused with Tyrode solution by Langendorff technique. After stabilization of baseline hemodynamics, the hearts were subjected to 45-minute global ischemia followed by a 120-minute reperfusion with IP(IP group, n=13) or without IP(ischemic control, n=10). IP was induced by single episode of 5-minute global ischemia and 10-minute reperfusion. In the Ca2+ preconditioned group, perfusate containing 10(n=10) or 20 mM(n=11) CaCl2 was perfused for 10 minutes after 5-minute ischemia followed by a 45-minute global ischemia and a 120-minute reperfusion. Baseline PKC was measured after 50-minute perfusion without any treatment(n=5). Left ventricular function including developed pressure(LVDP), dP/dt, heart rate, left ventricular end-diastolic pressure(LVEDP) and coronary flow(CF) was measured. Myo car ial cytosolic and membrane PKC activities were measured by 32P-${\gamma}$-ATP incorporation into PKC-specific pepetide. The infarct size was determined using the TTC (tetrazolium salt) staining and planimetry. Data were analyzed using one-way analysis of variance(ANOVA) variance(ANOVA) and Tukey's post-hoc test. Result: IP increased the functional recovery including LVDP, dP/dt and CF(p<0.05) and lowered the ascending range of LVEDP(p<0.05); it also reduced the infarct size from 38% to 20%(p<0.05). In both of the Ca2+ preconditioned group, functional recovery was not significantly different in comparison with the ischemic control, however, the infarct size was reduced to 19∼23%(p<0.05). In comparison with the baseline(7.31 0.31 nmol/g tissue), the activities of the cytosolic PKC tended to decrease in both the IP and Ca2+ preconditioned groups, particularly in the 10 mM Ca2+ preconditioned group(4.19 0.39 nmol/g tissue, p<0.01); the activity of membrane PKC was significantly increased in both IP and 10 mM Ca2+ preconditioned group (p<0.05; 1.84 0.21, 4.00 0.14, and 4.02 0.70 nmol/g tissue in the baseline, IP, and 10 mM Ca2+ preconditioned group, respectively). However, the activity of both PKC fractions were not significantly different between the baseline and the ischemic control. Conclusion: These results indicate that in isolated Langendorff-perfused rabbit heart model, calcium preconditioning with high concentration of calcium does not improve post-ischemic functional recovery. However, it does have an effect of limiting(reducing) the infart size by ischemic preconditioning, and this cardioprotective effect, at least in part, may have resulted from the activation of PKC by calcium which acts as a messenger(or trigger) to activate membrane PKC.

  • PDF

Therapeutic Angiogenesis by Intramyocardial Injection of pCK-VEGF165 in Pigs (돼지에서 pCK-VEGF165의 심근내 주입에 의한 치료적 혈관조성)

  • Choi Jae-Sung;Han Woong;Kim Dong Sik;Park Jin Sik;Lee Jong Jin;Lee Dong Soo;Kim Ki-Bong
    • Journal of Chest Surgery
    • /
    • v.38 no.5 s.250
    • /
    • pp.323-334
    • /
    • 2005
  • Background: Gene therapy is a new and promising option for the treatment of severe myocardial ischemia by therapeutic angiogenesis. The goal of this study was to elucidate the efficacy of therapeutic angiogenesis by using VEGF165 in large animals. Material and Method: Twenty-one pigs that underwent ligation of the distal left anterior descending coronary artery were randomly allocated to one of two treatments: intramyocardial injection of pCK-VEGF (VEGF) or intramyocardial injection of pCK-Null (Control). Injections were administered 30 days after ligation. Seven pigs died during the trial, but eight pigs from VEGF and six from Control survived. Echo-cardiography was performed on day 0 (preoperative) and on days 30 and 60 following coronary ligation. Gated myocardial single photon emission computed tomography imaging (SPECT) with $^{99m}Tc-labeled$ sestamibi was performed on days 30 and 60. Myocardial perfusion was assessed from the uptake of $^{99m}Tc-labeled$ sestamibi at rest. Global and regional myocardial function as well as post-infarction left ventricular remodeling were assessed from segmental wall thickening; left ventricular ejection fraction (EF); end systolic volume (ESV); and end diastolic volume (EDV) using gated SPECT and echocardiography. Myocardium of the ischemic border zone into which pCK plasmid vector had been injected was also sampled to assess micro-capillary density. Result: Micro-capillary density was significantly higher in the VEGF than in Control ($386\pm110/mm^{2}\;vs.\;291\pm127/mm^{2};\;p<0.001$). Segmental perfusion increased significantly from day 30 to day 60 after intramyocardial injection of plasmid vector in VEGF ($48.4\pm15.2\%\;vs.\;53.8\pm19.6\%;\;p<0.001$), while no significant change was observed in the Control ($45.1\pm17.0\%\;vs.\;43.4\pm17.7\%;\;p=0.186$). This resulted in a significant difference in the percentage changes between the two groups ($11.4\pm27.0\%\;increase\;vs.\;2.7\pm19.0\%\;decrease;\;p=0.003$). Segmental wall thickening increased significantly from day 30 to day 60 in both groups; the increments did not differ between groups. ESV measured using echocardiography increased significantly from day 0 to day 30 in VEGF ($22.9\pm9.9\;mL\;vs.\;32.3\pm9.1\;mL;\; p=0.006$) and in Control ($26.3\pm12.0\;mL\;vs.\;36.8\pm9.7\;mL;\;p=0.046$). EF decreased significantly in VEGF ($52.0\pm7.7\%\;vs.\;46.5\pm7.4\%;\;p=0.004$) and in Control ($48.2\pm9.2\%\;vs.\;41.6\pm10.0\%;\;p=0.028$). There was no significant change in EDV. The interval changes (days $30\~60$) of EF, ESV, and EDV did not differ significantly between groups both by gated SPECT and by echocardiography. Conclusion: Intramyocardial injection of pCK-VEGF165 induced therapeutic angiogenesis and improved myocardial perfusion. However, post-infarction remodeling and global myocardial function were not improved.