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Electrocardiographic changes during induced hemorrhagic shock in anesthetized dogs: Predictors of the severity of shock-induced metabolic imbalances
Abstracts
0105 Characterization of an anesthetized dog model of simulated angina for detection of drug-induced conduction slowing and ventricular proarrhythmia Bruce P. Damianob, Henk Van der Lindea, Bruno Van Beurena, Yves Somersa, Ard Teismana, David J. Gallachera a
Janssen Research and Development, Beerse, Belgium Janssen Research and Development, Spring House, PA, USA
b
doi:10.1016/j.vascn.2014.03.111
DP
Assessment of electrocardiographic safety and proarrhythmic risk of development candidates is currently focused predominantly on repolarization abnormalities. However, drug-induced conduction slowing can increase risk of life-threatening ventricular arrhythmias, particularly during ischemia. Therefore, we developed an anesthetized dog model for evaluating compounds with propensity to slow conduction, during transient local ischemia and rapid pacing to simulate angina. Dogs were instrumented with atrial and ventricular electrodes for pacing and conduction time measurement and, a balloon occluder and flow probe around the left anterior descending coronary artery (LAD) distal to the first branch. Conduction times, ECG intervals and arrhythmia incidence following each incremental intravenous dose of flecainide (0.32–5 mg/kg), dofetilide (1.25–20 μg/kg) or vehicle were assessed prior to and during 10-min LAD occlusion, without and with pacing. Flecainide produced dose-dependent conduction slowing that was exacerbated during ischemia and rapid pacing. In addition, ventricular tachycardia and fibrillation were induced in 4 of 6 dogs (3 VF @ 0.63 mg/kg; 1VT @ 2.5 mg/kg). In contrast, only 1 of 9 vehicle animals developed arrhythmias. Dofetilide, a potent IKr blocker, prolonged QT interval but caused no further conduction slowing during ischemia and pacing, and no arrhythmias. Compound X, a potential development candidate with mild conduction slowing properties, produced more pronounced conduction slowing and ventricular arrhythmias in 6 of 8 dogs during ischemia + pacing. Thus, this model may be useful to define shifts in drug safety margins in patients with ischemia (e.g., angina) where reduced supply and increased cardiac demand alters normal conduction.
OF
doi:10.1016/j.vascn.2014.03.109
studies. We evaluated in six healthy cats a new noninvasive method, high definition oscillometry (HDO®) including pulse wave analyses, by comparison to an invasive method using radiotelemetry devices. Under standardized recording conditions, 5 systolic blood pressure (SBP) and diastolic blood pressure (DBP) paired measurements within the normal physiological range (SBP: 110–149 mm Hg, DBP: 50– 89 mm Hg) were recorded using both methods. For comparison of data achieved with these two different methods, correlation coefficient (r) of paired measurements from the two methods was determined with 0.92 as well as, the mean difference of paired measurements, 88% of paired measurements lying within a difference less than 10 mm Hg and 96% of paired measurements lying within a difference less than 20 mm Hg. Moreover, the agreement between the two methods was assessed using the method described by Bland and Altman with a bias of − 2.2. Additionally pulse wave analysis (PWA) was performed to further detail the results. Under these experimental conditions, SBP and DBP values achieved with HDO® and telemetry displayed a significant correlation in all cats. AAMI and ACVIM standards have first time been met and even exceeded. These preliminary data suggest that measurement of arterial blood pressure with HDO® in awake healthy cats provides values matching with those achieved with the gold standard invasive method for arterial blood pressure measurement.
RO
9 ± 5, 19 ± 4*, 40 ± 9* %) or not (dP/dtmax/EDP: 10 ± 7, 25 ± 6*, 54 ± 12* %), were able to differentiate between dose-levels. (*: P b 0.05) The data suggests that the assessment of inotropic responses may be aided by leveraging indices of preload and lusitropy to correct load-dependent LVP-derived indices of contractility.
341
0107
TE
Electrocardiographic changes during induced hemorrhagic shock in anesthetized dogs: Predictors of the severity of shock-induced metabolic imbalances Robert Georgea, Carlos del Rioa, Bradley Youngblooda, Yukie Ueyamaa, Pamela Kloepfera, William Muira, Hamlin Roberta,b a
QTest Labs, Columbus, OH, USA The Ohio State University, Columbus, OH, USA
CO
RR
EC
b
doi:10.1016/j.vascn.2014.03.110
UN
0106
Comparison of HDO® (high definition oscillometry), a novel noninvasive technology for arterial blood pressure measurement, to a direct invasive method using radiotelemetric equipment in awake healthy cats Beate Egnera, Jonathan N. Kingb, Arnaux Laveissierec, Eric Martelc a
Clinical Center for Small Animals, Hoerstein, Germany Novartis Animal Health Inc., Basel, Switzerland c Centre de Recherches Biologique (CERB), Baugy, France b
Blood pressure is a key parameter needed in various preclinical trials of Safety Pharmacology especially when included in toxicology
Rapid identification of oxygen-debt accumulation during hemorrhagic shock is necessary to mitigate hypoperfusion, tissue hypoxia, and cellular death. Shock is traditionally diagnosed by both hemodynamic (hypotension, tachycardia) and metabolic (hyperlactatemia) criteria. Electrocardiogram-derived indices have not been used to aid the detection of metabolic disturbances and/or shock. This study evaluated changes in morphologic, dromotropic, conduction, and repolarization indices of the body surface electrocardiogram during the induction and maintenance of hemorrhagic shock, and correlated these changes to biochemical surrogates (blood lactate) of shockinduced oxygen debt. Isoflurane anesthetized dogs (n = 13) were bled in order to maintain a mean arterial blood pressure of 30– 40 mm Hg. The blood lactate was measured before hemorrhage (baseline) and every 15 min until a lactate ≥6 mM/L (shock) was achieved. A lead II electrocardiogram was recorded over this entire time period. The following electrocardiographic measurements were subsequently performed and compared: heart rate, PQ-interval, QRSinterval, QT-interval (corrected), T-peak to T-end, P-amplitude, Ramplitude, S-amplitude, ST-level, and P:R ratio. Shock produced significant (P b 0.05) changes in heart rate (135 ± 6 to 216 ± 6 bpm), PQ-interval (88 ± 3 to 65 ± 1 ms), QT-interval (283 ± 4 to 270 ± 2 ms), and the amplitudes of the P (1.44 ± 0.10 to 1.99 ± 0.10 mV) and R waves (5.37 ± 0.35 to 3.66 ± 0.45 mV) and their ratio (P:R: 0.29 ± 0.03 to 0.79 ± 0.19). Notably, within each animal, both heart rate (slope = 0.05 ± 0.00, R2 = 0.85 ± 0.03) and P:R ratio (slope = 7.14 ± 2.03, R2 = 0.73 ± 0.04) were good predictors of blood lactate accumulation during shock. In conclusion, electrocardiographic indices
Abstracts
doi:10.1016/j.vascn.2014.03.112
0108 The usefulness of echocardiography in exploring of predictive biomarkers for rosiglitazone-induced cardiac hypertrophy Katsuyuki Kazusa, Takafumi Shirakawa, Shoko Kida, Yudai Watanabe, Daisuke Sasaki, Takeji Ohata Astellas Pharma Inc., Osaka, Japan
doi:10.1016/j.vascn.2014.03.114
DP
Echocardiography, an imaging technique that allows investigation of the cardiac morphology and function, has just been in use with increasing frequency to evaluate efficacy and safety of novel compounds in animals during drug discovery and development. In the present study, we investigated the usefulness of echocardiography in exploration of predictive biomarkers for cardiac hypertrophy induced by rosiglitazone (RGZ) which is known to induce fluid retention via its pharmacological effect. Male SD rats were orally administered with RGZ for 14 days (0 and 100 mg/kg/day, Experiment 1) or for 7 days (0, 10 and 30 mg/kg/day, Experiment 2). Echocardiography, hematology, clinical chemistry, and histopathology were evaluated after 7 and 14 (only in 100 mg/kg) days of dosing. In Experiment 1, heart weight increased without any histopathological changes after 7 days of dosing or later, and changes related to cardiac hypertrophy or fluid retention (e.g. decreases in concentrations of electrolytes, red blood cell, and hemoglobin, increases in cardiac wall thickness, left ventricular mass, and aortic outflow velocity in echocardiography, etc.) were observed. In Experiment 2 as the lower doses study, similar changes in echocardiography to Experiment 1 were observed as well at 10 mg/kg or more, whereas other examinations detected decreased red blood cell and hemoglobin concentration and increased pro-ANP and cTnI only at 30 mg/kg. Thus, it was demonstrated that functional changes were more sensitive than parameters in blood chemistry and hematology to predict the RGZ-induced cardiac hypertrophy and that the echocardiography is a useful tool in exploration of biomarkers.
based on animals or altered mammalian cell lines; since human SCCMs better represent the physiology of adult cardiomyocytes, can be reproducibly generated on demand, kept in culture for prolonged periods of time, and can be chosen to represent different genetic profiles. The limitation of these systems however, is that they use rigid conventional MEAs and therefore are static. Most drug induced arrhythmias occur during physical exercise when heart cells are increasingly stretched to provide the required cardiac output. The response of the heart to increased load is enabled by an electromechanical feedback mechanism through different mechanotransduction phenomena in cardiomyocytes. Therefore, it is important for an in vitro cardiotoxicity assay to recapitulate the cyclic mechanical stretching of cardiomyocytes during electrophysiological measurements. This paper presents an innovative design and fabrication technology for a manufacturable Stretchable Micro-Electrode Array (SMEA) incorporating human SC-CMs as an electrophysiological assay for cardiotoxicity with the capability of applying physiologically relevant mechanical stimulation to attached cardiomyocytes. Electromechanical characterization and cellular biocompatibility of the SMEA are presented.
OF
such as heart rate the P:R ratio may help detect/quantify the severity of shock-induced metabolic imbalances/oxygen-debt accumulation.
RO
342
0110
TE
Relationship between dP/dtmax, QA interval, contractility index, and preload recruitable stroke work in anesthetized guinea pigs Anusak Kijtawornrata, Yukie Ueyamab, Carlos del Riob, Suwanakiet Sawangkoona, Chollada Buranakarla, Narongsak Chaiyabutra, Robert L. Hamlinb,c
0109
CO
doi:10.1016/j.vascn.2014.03.113
RR
EC
a Department of Veterinary Physiology, Faculty of Veterinary Science, Chulalongkorn University, Pathumwan, Bangkok, Thailand b QTest Labs, LLC., Columbus, OH, USA c Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, USA
a
UN
A platform for cardiotoxicity screening based on manufacturable Stretchable Micro-Electrode Arrays (SMEAs) Saeed Khoshfetrat Pakazada, Anja van de Stolpeb, Ronald Dekkera,b TU Delft, Delft, The Netherlands Philips Research Eindhoven, Eindhoven, The Netherlands
b
Cardiotoxicity has been an important and frequent cause of withdrawal of drugs from the market and drug compound attrition in preclinical and clinical drug development. This highlights an unmet need for improved and more predictive cardiotoxicity assays. In vitro human models based on the electrophysiological measurements from stem-cell derived cardiomyocytes (SC-CMs) cultured on Micro-Electrode Arrays (MEAs) have recently been explored as novel promising tools for cardiotoxicity screening. These models overcome some of the drawbacks of current conventional systems
Guinea pigs are among the most useful animal models serving as surrogates for humans in Safety Pharmacological studies. It has been known that inotropy may determine or inferred from either invasive or noninvasive methods. However, the gold standard for the measurement of inotrope is the parameter obtained from pressure– volume relationship. This study was aimed to evaluate the relationship between dP/dtmax, QA interval, contractility index (the maximal dP/dtmax divided by the left ventricular pressure at this point), and preload recruitable stroke work in anesthetized guinea pigs. Twenty-nine guinea pigs were anesthetized and instrumented to record left ventricular pressure volume relationship, aortic pressure, and electrocardiograms. After baseline and vehicle measurement, escalating concentrations of four test articles were infused intravenously (chromanol 293B, metoprolol, milrinone, and nicorandil). The contractility index (CI) relates linearly and significantly (r2 = 0.952, p b 0.001) to PRSW; dP/dtmax relates linearly (p = 0.029) but with an r2 of only 0.251 to PRSW; the QA interval relates linearly (p = 0.002) but with an r2 of only 0.456. Thus this study demonstrated that contractility index is a favorable predictor of contractility, but that neither dP/dtmax, nor QA interval is acceptable in anesthetized guinea pig.
doi:10.1016/j.vascn.2014.03.115
0105 Characterization of an anesthetized dog model of simulated angina for detection of drug-induced conduction slowing and ventricular proarrhythmia Bruce P. Damianob, Henk Van der Lindea, Bruno Van Beurena, Yves Somersa, Ard Teismana, David J. Gallachera a
Janssen Research and Development, Beerse, Belgium Janssen Research and Development, Spring House, PA, USA
b
doi:10.1016/j.vascn.2014.03.111
DP
Assessment of electrocardiographic safety and proarrhythmic risk of development candidates is currently focused predominantly on repolarization abnormalities. However, drug-induced conduction slowing can increase risk of life-threatening ventricular arrhythmias, particularly during ischemia. Therefore, we developed an anesthetized dog model for evaluating compounds with propensity to slow conduction, during transient local ischemia and rapid pacing to simulate angina. Dogs were instrumented with atrial and ventricular electrodes for pacing and conduction time measurement and, a balloon occluder and flow probe around the left anterior descending coronary artery (LAD) distal to the first branch. Conduction times, ECG intervals and arrhythmia incidence following each incremental intravenous dose of flecainide (0.32–5 mg/kg), dofetilide (1.25–20 μg/kg) or vehicle were assessed prior to and during 10-min LAD occlusion, without and with pacing. Flecainide produced dose-dependent conduction slowing that was exacerbated during ischemia and rapid pacing. In addition, ventricular tachycardia and fibrillation were induced in 4 of 6 dogs (3 VF @ 0.63 mg/kg; 1VT @ 2.5 mg/kg). In contrast, only 1 of 9 vehicle animals developed arrhythmias. Dofetilide, a potent IKr blocker, prolonged QT interval but caused no further conduction slowing during ischemia and pacing, and no arrhythmias. Compound X, a potential development candidate with mild conduction slowing properties, produced more pronounced conduction slowing and ventricular arrhythmias in 6 of 8 dogs during ischemia + pacing. Thus, this model may be useful to define shifts in drug safety margins in patients with ischemia (e.g., angina) where reduced supply and increased cardiac demand alters normal conduction.
OF
doi:10.1016/j.vascn.2014.03.109
studies. We evaluated in six healthy cats a new noninvasive method, high definition oscillometry (HDO®) including pulse wave analyses, by comparison to an invasive method using radiotelemetry devices. Under standardized recording conditions, 5 systolic blood pressure (SBP) and diastolic blood pressure (DBP) paired measurements within the normal physiological range (SBP: 110–149 mm Hg, DBP: 50– 89 mm Hg) were recorded using both methods. For comparison of data achieved with these two different methods, correlation coefficient (r) of paired measurements from the two methods was determined with 0.92 as well as, the mean difference of paired measurements, 88% of paired measurements lying within a difference less than 10 mm Hg and 96% of paired measurements lying within a difference less than 20 mm Hg. Moreover, the agreement between the two methods was assessed using the method described by Bland and Altman with a bias of − 2.2. Additionally pulse wave analysis (PWA) was performed to further detail the results. Under these experimental conditions, SBP and DBP values achieved with HDO® and telemetry displayed a significant correlation in all cats. AAMI and ACVIM standards have first time been met and even exceeded. These preliminary data suggest that measurement of arterial blood pressure with HDO® in awake healthy cats provides values matching with those achieved with the gold standard invasive method for arterial blood pressure measurement.
RO
9 ± 5, 19 ± 4*, 40 ± 9* %) or not (dP/dtmax/EDP: 10 ± 7, 25 ± 6*, 54 ± 12* %), were able to differentiate between dose-levels. (*: P b 0.05) The data suggests that the assessment of inotropic responses may be aided by leveraging indices of preload and lusitropy to correct load-dependent LVP-derived indices of contractility.
341
0107
TE
Electrocardiographic changes during induced hemorrhagic shock in anesthetized dogs: Predictors of the severity of shock-induced metabolic imbalances Robert Georgea, Carlos del Rioa, Bradley Youngblooda, Yukie Ueyamaa, Pamela Kloepfera, William Muira, Hamlin Roberta,b a
QTest Labs, Columbus, OH, USA The Ohio State University, Columbus, OH, USA
CO
RR
EC
b
doi:10.1016/j.vascn.2014.03.110
UN
0106
Comparison of HDO® (high definition oscillometry), a novel noninvasive technology for arterial blood pressure measurement, to a direct invasive method using radiotelemetric equipment in awake healthy cats Beate Egnera, Jonathan N. Kingb, Arnaux Laveissierec, Eric Martelc a
Clinical Center for Small Animals, Hoerstein, Germany Novartis Animal Health Inc., Basel, Switzerland c Centre de Recherches Biologique (CERB), Baugy, France b
Blood pressure is a key parameter needed in various preclinical trials of Safety Pharmacology especially when included in toxicology
Rapid identification of oxygen-debt accumulation during hemorrhagic shock is necessary to mitigate hypoperfusion, tissue hypoxia, and cellular death. Shock is traditionally diagnosed by both hemodynamic (hypotension, tachycardia) and metabolic (hyperlactatemia) criteria. Electrocardiogram-derived indices have not been used to aid the detection of metabolic disturbances and/or shock. This study evaluated changes in morphologic, dromotropic, conduction, and repolarization indices of the body surface electrocardiogram during the induction and maintenance of hemorrhagic shock, and correlated these changes to biochemical surrogates (blood lactate) of shockinduced oxygen debt. Isoflurane anesthetized dogs (n = 13) were bled in order to maintain a mean arterial blood pressure of 30– 40 mm Hg. The blood lactate was measured before hemorrhage (baseline) and every 15 min until a lactate ≥6 mM/L (shock) was achieved. A lead II electrocardiogram was recorded over this entire time period. The following electrocardiographic measurements were subsequently performed and compared: heart rate, PQ-interval, QRSinterval, QT-interval (corrected), T-peak to T-end, P-amplitude, Ramplitude, S-amplitude, ST-level, and P:R ratio. Shock produced significant (P b 0.05) changes in heart rate (135 ± 6 to 216 ± 6 bpm), PQ-interval (88 ± 3 to 65 ± 1 ms), QT-interval (283 ± 4 to 270 ± 2 ms), and the amplitudes of the P (1.44 ± 0.10 to 1.99 ± 0.10 mV) and R waves (5.37 ± 0.35 to 3.66 ± 0.45 mV) and their ratio (P:R: 0.29 ± 0.03 to 0.79 ± 0.19). Notably, within each animal, both heart rate (slope = 0.05 ± 0.00, R2 = 0.85 ± 0.03) and P:R ratio (slope = 7.14 ± 2.03, R2 = 0.73 ± 0.04) were good predictors of blood lactate accumulation during shock. In conclusion, electrocardiographic indices
Abstracts
doi:10.1016/j.vascn.2014.03.112
0108 The usefulness of echocardiography in exploring of predictive biomarkers for rosiglitazone-induced cardiac hypertrophy Katsuyuki Kazusa, Takafumi Shirakawa, Shoko Kida, Yudai Watanabe, Daisuke Sasaki, Takeji Ohata Astellas Pharma Inc., Osaka, Japan
doi:10.1016/j.vascn.2014.03.114
DP
Echocardiography, an imaging technique that allows investigation of the cardiac morphology and function, has just been in use with increasing frequency to evaluate efficacy and safety of novel compounds in animals during drug discovery and development. In the present study, we investigated the usefulness of echocardiography in exploration of predictive biomarkers for cardiac hypertrophy induced by rosiglitazone (RGZ) which is known to induce fluid retention via its pharmacological effect. Male SD rats were orally administered with RGZ for 14 days (0 and 100 mg/kg/day, Experiment 1) or for 7 days (0, 10 and 30 mg/kg/day, Experiment 2). Echocardiography, hematology, clinical chemistry, and histopathology were evaluated after 7 and 14 (only in 100 mg/kg) days of dosing. In Experiment 1, heart weight increased without any histopathological changes after 7 days of dosing or later, and changes related to cardiac hypertrophy or fluid retention (e.g. decreases in concentrations of electrolytes, red blood cell, and hemoglobin, increases in cardiac wall thickness, left ventricular mass, and aortic outflow velocity in echocardiography, etc.) were observed. In Experiment 2 as the lower doses study, similar changes in echocardiography to Experiment 1 were observed as well at 10 mg/kg or more, whereas other examinations detected decreased red blood cell and hemoglobin concentration and increased pro-ANP and cTnI only at 30 mg/kg. Thus, it was demonstrated that functional changes were more sensitive than parameters in blood chemistry and hematology to predict the RGZ-induced cardiac hypertrophy and that the echocardiography is a useful tool in exploration of biomarkers.
based on animals or altered mammalian cell lines; since human SCCMs better represent the physiology of adult cardiomyocytes, can be reproducibly generated on demand, kept in culture for prolonged periods of time, and can be chosen to represent different genetic profiles. The limitation of these systems however, is that they use rigid conventional MEAs and therefore are static. Most drug induced arrhythmias occur during physical exercise when heart cells are increasingly stretched to provide the required cardiac output. The response of the heart to increased load is enabled by an electromechanical feedback mechanism through different mechanotransduction phenomena in cardiomyocytes. Therefore, it is important for an in vitro cardiotoxicity assay to recapitulate the cyclic mechanical stretching of cardiomyocytes during electrophysiological measurements. This paper presents an innovative design and fabrication technology for a manufacturable Stretchable Micro-Electrode Array (SMEA) incorporating human SC-CMs as an electrophysiological assay for cardiotoxicity with the capability of applying physiologically relevant mechanical stimulation to attached cardiomyocytes. Electromechanical characterization and cellular biocompatibility of the SMEA are presented.
OF
such as heart rate the P:R ratio may help detect/quantify the severity of shock-induced metabolic imbalances/oxygen-debt accumulation.
RO
342
0110
TE
Relationship between dP/dtmax, QA interval, contractility index, and preload recruitable stroke work in anesthetized guinea pigs Anusak Kijtawornrata, Yukie Ueyamab, Carlos del Riob, Suwanakiet Sawangkoona, Chollada Buranakarla, Narongsak Chaiyabutra, Robert L. Hamlinb,c
0109
CO
doi:10.1016/j.vascn.2014.03.113
RR
EC
a Department of Veterinary Physiology, Faculty of Veterinary Science, Chulalongkorn University, Pathumwan, Bangkok, Thailand b QTest Labs, LLC., Columbus, OH, USA c Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, USA
a
UN
A platform for cardiotoxicity screening based on manufacturable Stretchable Micro-Electrode Arrays (SMEAs) Saeed Khoshfetrat Pakazada, Anja van de Stolpeb, Ronald Dekkera,b TU Delft, Delft, The Netherlands Philips Research Eindhoven, Eindhoven, The Netherlands
b
Cardiotoxicity has been an important and frequent cause of withdrawal of drugs from the market and drug compound attrition in preclinical and clinical drug development. This highlights an unmet need for improved and more predictive cardiotoxicity assays. In vitro human models based on the electrophysiological measurements from stem-cell derived cardiomyocytes (SC-CMs) cultured on Micro-Electrode Arrays (MEAs) have recently been explored as novel promising tools for cardiotoxicity screening. These models overcome some of the drawbacks of current conventional systems
Guinea pigs are among the most useful animal models serving as surrogates for humans in Safety Pharmacological studies. It has been known that inotropy may determine or inferred from either invasive or noninvasive methods. However, the gold standard for the measurement of inotrope is the parameter obtained from pressure– volume relationship. This study was aimed to evaluate the relationship between dP/dtmax, QA interval, contractility index (the maximal dP/dtmax divided by the left ventricular pressure at this point), and preload recruitable stroke work in anesthetized guinea pigs. Twenty-nine guinea pigs were anesthetized and instrumented to record left ventricular pressure volume relationship, aortic pressure, and electrocardiograms. After baseline and vehicle measurement, escalating concentrations of four test articles were infused intravenously (chromanol 293B, metoprolol, milrinone, and nicorandil). The contractility index (CI) relates linearly and significantly (r2 = 0.952, p b 0.001) to PRSW; dP/dtmax relates linearly (p = 0.029) but with an r2 of only 0.251 to PRSW; the QA interval relates linearly (p = 0.002) but with an r2 of only 0.456. Thus this study demonstrated that contractility index is a favorable predictor of contractility, but that neither dP/dtmax, nor QA interval is acceptable in anesthetized guinea pig.
doi:10.1016/j.vascn.2014.03.115