• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.100-100
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• 2003

Pluripotent embryonic stem (ES) cells differentiate spontaneously into beating cardiomyocytes via embryo-like aggregates. We describe the use of mouse embryonic stem (mES03) cells as a reproducible differentiation system for cardiomyocyte. To induce cardiomyocytic differentiation, mES03 cells were dissociated and allowed to aggregate (EB formation) at the presence of 0 75% dimethyl sulfoxide (DMSO) for 4 days and then another 4 days without DMSO (4+/4-). Thus treated EBs were plated onto gelatin-coated dish for differentiation. Spontaneously contracting colonies which appeared in approximately 4-5 days upon differentiation. Expression of cardiac-specific genes were determined by RT-PCR. Rebust expression of myosin light chain (MLC-2V), cardiac myosin heavy chain $\alpha$, cardiac muscle heavy polypeptide 7 $\beta(\beta$-MHC), cardiac transcription factor GATA4 and skeletal muscle-specific ${\alpha}_1$-subunit of the L-type calcium channel (${\alpha}_1 CaCh_{sm}$) were detected as early as 8 days after EB formation, but message of cardiac muscle-specific $\alpha$$_1$-subunit of the L-type calcium channel (${\alpha}_1$CaCh) were revealed at a low level. Strikingly, the expression of atrial natriuretic factor (ANF) was not detected. When spontaneous contracting cell masses were examined their electrophysiological features by patch-clamp technique, it showed ventricle-like action potential 17 days after the EB formation. This study indicates that mES03 cell-derived cardiomyocytes displayed biochemical and electrophysiological properties of cardiomyocytes and DMSO enhanced development of cardiomyocytes in 4+/4- method.

• Archives of Pharmacal Research
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• v.29 no.1
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• pp.34-39
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• 2006

The antispasmodic and vasodilator activities of a newly synthesized piperidine derivative (1-(4'fluorophenacyl)-4-hydroxy-4-phenyl-piperidinium chloride) were studied in vitro. The test compound exhibited a dose-dependent relaxant effect on the spontaneous and $K^+$ (75 mM)-induced contractions of isolated rabbit jejunum with respective $EC_{50}$ values of 0.01 mM(0.01-0.02, 95% CI) and 0.30 mM (0.17-0.56). The $Ca^{++}$ channel blocking (CCB) activity was confirmed when the test compound (0.1-0.2 mM) shifted the $Ca^{++}$ dose-response curves to the right, similar to that produced by verapamil ($0.1-1.0{\mu}M$), a standard CCB. In the isolated rabbit aorta, the test compound showed a dose-dependent vasodilator effect on $K^+$ (75 mM)-induced contractions with an $EC_{50}$ value of 0.08 mM (0.02-0.26) while also suppressed the norepinephrine ($1{\mu}M$) control peak responses with $EC_{50}$ value of 0.08 mM (0.05-0.13, n=5). When tested in Langendorff perfused rabbit heart preparation, the test compound exhibited a negligible inhibitory effect on the rate or force of atrial and ventricular contractions when tested up to 5 mM. The results show smooth muscle-selective relaxant effect of the test compound on intestinal and vascular preparations mediated possibly via blockade of voltage and receptor-operated $Ca^{++}$ channels.

• Korean Journal of Veterinary Research
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• v.27 no.1
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• pp.27-34
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• 1987

To verify the direct effects of the thyroid hormone ($T_3$) on the rabbit heart, $T_3$-Tyrode solution in vitro was perfused on the normal atrial muscles and enzymatically isolated ventricular myocytes of the rabbit. All the experimental procedures were conducted at $35^{\circ}C$ and the same procedures were repeated after Ca. 120 minutes from the beginning of $T_3$-Tyrode perfusion. Compared to the state between the normal Tyrode solution and $T_3$-Tyrode solution, results were observed on the same cells by electrophysiological methods (conventional intracellular recording and whole cell patch clamping) as soon as possible. The results obtained were as follows : 1. Action potential duration (APD) on the left atrial muscle was reduced under the perfusion of $T_3$-Tyrode. 2. Absolute refractory Period was shortened by $T_3$-Tryrode perfusion. (117 msec./114 msec., 90 msec./78 msec.) 3. Maximal Ca currents ($i_{Ca}$) were decreased in single: ventricular myocytes under the $T_3$-Tyrode (2.98 nA) than under the normal Tyrode (6.65 nA) 4. On I-V relation, reversal potential was shifted to lower membrane potential and membrane potential showing maximal $i_{Ca}$was lowered from +10mV to -20mV by $T_3$ effect. 5. Above results were likely to explain that tachycardia in the hyperthyroid state was caused in part by the reduced repolarization phase and the reduced refractory period due to the decrease of the Ca current.

• Journal of Biomedical Engineering Research
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• v.43 no.4
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• pp.280-289
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• 2022

In this paper, we present a QRS-complex detection algorithm to calculate an accurate heartbeat and clearly recognize irregular rhythm from ECG signals. The conventional Pan-Tompkins algorithm brings false QRS detection in the derivative when QRS and noise signals have similar instant variation. The proposed algorithm uses amplitude differences in 7 adjacent samples to detect QRS-complex which has the highest amplitude variation. The calculated amplitude is cubed to dominate QRS-complex and the moving average method is applied to diminish the noise signal's amplitude. Finally, a decision rule with a threshold value is applied to detect accurate QRS-complex. The calculated signals with Pan-Tompkins and proposed algorithms were compared by signal-to-noise ratio to evaluate the noise reduction degree. QRS-complex detection performance was confirmed by sensitivity and the positive predictive value(PPV). Normal ECG, muscle noise ECG, PVC, and atrial fibrillation signals were achieved which were measured from an ECG simulator. The signal-to-noise ratio difference between Pan-Tompkins and the proposed algorithm were 8.1, 8.5, 9.6, and 4.7, respectively. All ratio of the proposed algorithm is higher than the Pan-Tompkins values. It indicates that the proposed algorithm is more robust to noise than the Pan-Tompkins algorithm. The Pan-Tompkins algorithm and the proposed algorithm showed similar sensitivity and PPV at most waveforms. However, with a noisy atrial fibrillation signal, the PPV for QRS-complex has different values, 42% for the Pan-Tompkins algorithm and 100% for the proposed algorithm. It means that the proposed algorithm has superiority for QRS-complex detection in a noisy environment.

• Journal of Chest Surgery
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• v.40 no.2 s.271
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• pp.136-139
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• 2007

Bilateral popliteal artery entrapment syndrome is a rare vascular disease, which leads to ischemic claudication as a result of disturbance to the blood flow from the abnormal relationship of the popliteal artery to the gastrocnemius muscle, a fibrous band or the popliteus muscle in the young male population. A 58-years-old male patient, complaining of ischemic claudication, coldness and 3rd toe gangrene of left leg of 1 month's duration was admitted to our institution. His left ankle-brachial index was decreased; therefore, a femoral artery angiography was peformed, which revealed a total occlusion below the distal superficial femoral artery of the left leg. An EKG revealed atrial fibrillation, suggestive of a thromboembolism of the popliteal artery due to atrial fibrillation; therefore, Urokinase thrombolysis was attempted. After the Urokinase thrombolysis, popliteal artery entrapment syndrome was diagnosed, with MRI then performed for an anatomical diagnosis. The popliteal artery entrapment was type 1, where the popliteal artery was displaced medial to the Gastrocnemius head. After complete removal of the popliteal artery aneurysm, interposition was performed with a contra lateral greater saphenous vein graft. A mild right popliteal artery aneurysm still remained, but surgery was not performed. Currently, the patent is surviving, without complications. Herein, the good results obtained for the surgical treatment of a severely affected leg, and the conservative treatment of a mildly affected leg, are reported.

• Korean Journal of Veterinary Research
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• v.39 no.5
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• pp.930-937
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• 1999

Atrial natriuretic peptide(ANP) is a hormone with potent natriuretic, diuretic and relaxing properties on vascular smooth muscle. Specific chemical modulator in response for the ANP secretion has not been found yet. Therefore, we have investigated the role of $Ca^{2+}$ responsible for the regulation of ANP induced by protein kinase C(PKC) on mechanically stretch-induced ANP secretion in the rat atria. The results obtained were as follows ; 1. ANP secretion and ANP concentration were increased to more in $Ca^{2+}$-free buffer than in the Kreb-Henseleit buffer on mechanically stretch-induced ANP secretion(p < 0.05), but extracellular fluid translocation(ECF) was not significant. Phorbol 12-myristate 13-acetate(PMA, $10^{-7}M$) induced ANP secretion and ANP concentration in $Ca^{2+}$-free buffer shown to more accentuate on mechanically stretch-induced ANP secretion than in the $Ca^{2+}$-free buffer(p < 0.05), but ECF translocation was not significant. 2. In the presence of ryanodine($3{\times}10^{-6}M$), PMA($10^{-7}M$) induced ANP secretion and ANP concentration in the Kreb-Henseleit buffer were shown to more increase on mechanically stretch-induced ANP secretion than in the ryanodine($3{\times}10^{-6}M$) with the Kreb-Henseleit buffer(p < 0.05), but ECF translocation was not significant. 3. In the presence of ryanodine($3{\times}10^{-6}M$), PMA($10^{-7}M$) induced ANP secretion and ANP concentration in the $Ca^{2+}$-free buffer was shown to more increase on mechanically stretch-induced ANP secretion than in the ryanodine($3{\times}10^{-6}M$) with the $Ca^{2+}$-free buffer on mechanically induced ANP secretion(p < 0.05), but ECF translocation was not significant. The results suggest that PKC-induced ANP secretion may not be related to the change of $Ca^{2+}$ on mechanically induced ANP secretion in the rat atria.

• The Korean Journal of Pharmacology
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• v.16 no.1 s.26
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• pp.41-50
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• 1980

Chenodeoxycholic acid(CDCA) has been used as a gallstone dissolving agent since 1972. Recently, ursodeoxycholic acid(UDCA) has been reported to be effective in dissolving gallstones. Both bile acids increased bile flow. The increase in bile flow associated with an increase in cholesterol level in bile after CDCA or UDCA infusion was reported. In this study, using the smooth muscle strips of guinea pig and fowl, responses of the cholates were observed. In addition, the influence of adrenergic blocking agents on the response of the strips to cholates was investigated. Also the effects of cholates on cardiac function were examined by using isolated atria of rabbit and heart of anesthetized frog. The results are as follows: 1) All cholates, such as UDCA, CDCA, and CA produced a marked inhibitory effect on the motility in isolated duodenal strip of guinea pig and fowl, however, only UDCA showed the contraction in the isolated esophagus of fowl. These effects of cholates were blocked by propranolol. 2) In isolated guinea pig stomach strip and gall bladder, cholates exhibited a marked inhibitory effect on the motility and the effects due to UDCA and CA were blocked by phenoxybenzamine while CDCA was not affected. 3) The spontaneous and ouabain induced arrhythmia was partially abolished by cholates. However, concomitant administration of cholates with ouabain or epinephrine caused a marked prolongation in occurrence of atrial arrhythmia in comparison with ouabain or epinephrine alone in isolated rabbit atria. 4) In the heart of anesthetized frog, the epinephrine-induced arrhythmia was partially abolished by cholates. The combined treatment with cholates and ouabain or epinephrine produced a marked prolongation in occurrence of the arrhythmia in comparison with, ouabain or epinephrine alone. From the above results, it can be suggested that the effects of cholates on the smooth muscle of duodenum and esophagus are produced in response to adrenergic ${\beta}$-receptor and the effect or gall bladder and stomach is more likely due to the direct effect on the muscle. In addition, cholates exhibit a slight antiarrhythmic effect on heart, therefore, cholates can be classified as a nonselective antiarrhythmic drug, such as propranolol.

• Journal of Food Hygiene and Safety
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• v.2 no.2
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• pp.57-65
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• 1987

ABSTRACT - To examine antihypertensive components of Ganoderma lucidum in Korea, two kinds of fruiting bodies (J and K) were used for extraction with water and the extracts were purified by ethanol precipitation and dialysis. Three fractions, i.e., the aqueous total extract(A), the ethanol supernatant(B} and the purified precipitate(C), were compared for antihypertensive activity in anesthetized spontaneously hypertensive rats (SUR). Although fractions A and B showed the activity, fraction C did not. Particularly, fraction B of sample K produced 44.3% reduction in diastolic blood pressure and 30.6% reduction in heart rate after i.v. administration of a dose of 10 mg/kg. Direct effects of this fraction B to the heart were observed in the isolated blood perfused heart preparation of the dog. It induced positive chronotropic and inotropic responses dose-dependently in the case of sample J. In the case of sample K, marked chronotropic and inotropic effects on atrial muscle but not on ventricular muscle were induced. In both samples, coronary blood flow (CBF) was dose-relatedly increased.reased.

• Journal of Chest Surgery
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• v.43 no.4
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• pp.413-416
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• 2010

A 47-year-old man presented with complaints of chest pain and dyspnea caused by deceleration injury due to an automobile accident. Systolic cardiac murmur was audible at the right sternal border. An electrocardiogram showed sinus tachycardia. Transthoracic echocardiography revealed a flailing anterior leaflet of the tricuspid valve, papillary muscle rupture, and severe valve insufficiency. Rupture of papillary muscle of the anterior leaflet and chordae tendineae of the posterior leaflet were confirmed by right atrial incision under routine cardiopulmonary bypass. Artificial chordae tendineaes were implanted between the anterior and posterior leaflet and papillary muscles in the right ventricles. De-Vega annuloplasty was also added. This is a very rare case in which a surgery was done for tricuspid valve regurgitation caused by post-traumatic papillary muscle rupture.

• The Korean Journal of Pharmacology
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• v.30 no.2
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• pp.181-190
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• 1994

In rat atrium the characteristics of purinergic receptors were investigated by observing the effects of some purinergic receptor agonists and antagonists on action potential and contractile force. The statistically significant effects of $ATP(10^{-6}{\sim}10^{-3}M)$ and adenosine $(10^{-6}{\sim}10^{-3}M)$ on normal action potential characteristics were a dose-dependent shortening of action potential duration $(APD_{90})$ by both agents and hyperpolarization by $ATP(10^{-4},10^{-3}M)$. $CAP(10^{-8}{\sim}10^{-4}M)$, an $A_1$ adenosine receptor agonist, shortened $(APD_{90})$ markedly in a dose-dependent manner and these effects were almost abolished by $DPCPX\;(10^{-6}\;M), an $A_1$, adenosine receptor antagonist, but not affected by $DMPX(2{\times}10^{-6}\;M)$, an $A_2$ adenosine receptor agonist. On the other hand, CGS $21680(10^{-7}{\sim}10^{-4}M)$, an $A_2$ adenosine receptor agonist, elicited a slight shortening of $(APD_{90})$ and these effects were inhibited by DPCPX but persisted in the presence of DPMX. Adenosine $(10^{-6}{\sim}10{\-4}\;M)$ decreased the basal contraction of atrial muscle in a dose-dependent manner and these effects were not inhibited by DMPX but by DPCPX. These results suggests that purinergic receptor agonists depress the cardiac activity by a short ening of action potential duration and this effect is mostly mediated by $A_1$ adenosine receptors in rat atrium.