• Journal of Korean Academy of Nursing
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• v.39 no.3
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• pp.311-320
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• 2009

Purpose: This study was to analyze research reports published in Korea on cardiac rehabilitation for patients with cardiovascular disease. Methods: Based on inclusion criteria, 19 research reports were included in this review. Published year of selected articles was between 1996 and 2008. Nineteen studies were analyzed by guidelines of the cardiac rehabilitation programs done by the American Heart Association(AHA) and Scottish Intercollegiate Guidelines Network(SIGN). Results: The characteristics of patients were mostly of ischemic heart disease, 50-59 yr old, and male. Educational sessions were administered twice, and each lesson lasted less than 30 min. Exercise was done 3 times per week for 6 weeks. Most educational content were about risk factors, but there was no information, such as coping with feelings. Most exercise was performed as ROM, treadmill, and cycle ergometer. A large percentage of outcome indicators were health behavior, hemodynamic changes, and exercise capacity. There was more 'no effect' than 'positive effect' in trait anxiety and depression, whereas similar in physiologic domain. Conclusion: Various types of cardiac rehabilitation in Korea were performed by researchers. Therefore, we need to develop the standard protocol, to add psychosocial intervention, and to study cost effectiveness of cardiac rehabilitation.

• The Korean Journal of Physiology
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• v.28 no.2
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• pp.133-141
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• 1994

The discharge patterns and peripheral nerve inputs to cardiovascular neurons were investigated in rostral ventrolateral medulla (RVLM) and raphe nucleus of cats. The data from the two were compared to determine their roles in cardiovascular regulation and the endogenous analgesic system. Animals were anesthetized with ${\alpha}-chloralose$ and single cell activities were recorded by carbon-filament microelectrode and their relationships with cardiovascular activity were analyzed. In RVLM area, a total of thirty-three cells were identified as cardiovascular neurons. During one cardiac cycle, the mean discharge rate of the neurons was $1.96{\pm}0.29$ and the peak activity was observed 45 ms after the systolic peak of arterial blood pressure. Thirteen cells could be activated antidromically by stimulation of the the $T_2$ intermediolateral nucleus. Forty-three raphe neurons were identified as cardiovascular neurons whose mean discharge rate during one cardiac cycle was $1.02{\pm}0.12$. None of these cells could be activated antidromically. Study of the interval time histogram of RVLM neurons revealed that the time to the first peak was $128{\pm}20.0\;ms$, being shorter than the period of a cardiac cycle. The same parameter found from the raphe neurons was $481{\pm}67.2\;ms$, which was much longer than the cardiac cycle length. Of seventeen RVLM neurons examined ten received only the peripheral $A{\delta}-afferent$ inputs, whereas six RVLM neurons received both $A{\delta}-$ and C-inputs; the remaining one cell received an inhibitory peripheral C-input. In contrast, nine of eleven raphe neurons were found to receive $A{\delta}-inputs$ only. We conclude that the main output of cardiovascular regulatory influences are mediated through the RVLM neurons. The cardiovascular neurons in the raphe nucleus appear to serve as interneurons transferring cardiovascular afferent information to the raphespinal neurons mediating the endogenous analgesic mechanisms.

• Molecules and Cells
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• v.24 no.3
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• pp.431-436
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• 2007

Stem cell-based therapy is being considered as an alternative treatment for cardiomyopathy. Hence understanding the basic molecular mechanisms of cardiomyocyte differentiation is important. Besides BMP or Wnt family proteins, $TGF-{\beta}$ family members are thought to play a role in cardiac development and differentiation. Although $TGF-{\beta}$ has been reported to induce cardiac differentiation in embryonic stem cells, the differential role of $TGF-{\beta}$ isoforms has not been elucidated. In this study, employing the DMSO-induced cardiomyocyte differentiation system using P19CL6 mouse embryonic teratocarcinoma stem cells, we investigated the $TGF-{\beta}$-induced signaling pathway in cardiomyocyte differentiation. $TGF-{\beta}1$, but not the other two isoforms of $TGF-{\beta}$, was induced at the mRNA and protein level at an early stage of differentiation, and Smad2 phosphorylation increased in parallel with $TGF-{\beta}1$ induction. Inhibition of $TGF-{\beta}1$ activity with $TGF-{\beta}1$-specific neutralizing antibody reduced cell cycle arrest as well as expression of the CDK inhibitor $p21^{WAF1}$. The antibody also inhibited induction of the cardiac transcription factor Nkx2.5. Taken together, these results suggest that $TGF-{\beta}1$ is involved in cardiomyocyte differentiation by regulating cell cycle progression and cardiac gene expression in an autocrine or paracrine manner.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.1
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• pp.33-38
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• 2008

Purpose: The Gated cardiac blood pool scan is non-invasive method that a quantitative evaluation of left ventricular function. Also this scan have shown the value of radionuclide ejection fraction measurements during the course of chemotherapy as a predictor of cardiac toxicity. Therefore a reliable method of monitoring its cardiotoxic effects is necessary. the purpose of this study is to minimize the overestimate of left ventricular ejection fraction (LVEF) by modified body position to reduce the influence of scattered rays from surrounding organs of the heart in the background region of interest. Materials and Methods: Gated cardiac blood pool scan using in vivo $^{99m}Tc$-red blood cell (RBC) was carried out in 20 patients (mean $44.8{\pm}8.6$ yr) with chemotherapy for a breast carcinoma. Data acquisition requires about 600 seconds and 24 frames of one heart cycle by the multigated acquisition mode, Synchronization deteriorates toward the end of the cycle and with the distance from the trigger signal (R-wave) by ECG gating. Gated cardiac blood pool scan was studied with conventional method (supine position and the detector head in $30-45^{\circ}$ left anterior oblique position and caudal $10-20^{\circ}$ tilt) and compared with modified method (left lateral flexion position with 360 mL of drinking water). LVEF analysis was performed by using the automatically computer mode. Results: The ROI counts of modified scan method were lower than LV conventional method ($1429{\pm}251$ versus $1853{\pm}243$, <0.01). And LVEF of modified method was also decrease compared with conventional method ($58.3{\pm}5.6%$ versus $65.3{\pm}6.1%$, <0.01). Imaging analysis indicated that stomach was expanded because of water and spleen position was changed to lateral inferior compared with conventional method. Conclusion: This study shows that the modified method in MUGA reduce the influence of scattered rays from surrounding organs. Because after change the body position to left lateral flexion and drinking water, the location of spleen, left lobe of liver and stomach had changed and they could escaped from background ROI. Therefore, modified method could help to minimize the overestimate LVEF (%).

• Biomolecules & Therapeutics
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• v.24 no.4
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• pp.363-370
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• 2016

Cardiovascular disease is the most common cause of death in diabetic patients. Hyperglycemia is the primary characteristic of diabetes and is associated with many complications. The role of hyperglycemia in the dysfunction of human cardiac progenitor cells that can regenerate damaged cardiac tissue has been investigated, but the exact mechanism underlying this association is not clear. Thus, we examined whether hyperglycemia could regulate mitochondrial dynamics and lead to cardiac progenitor cell dysfunction, and whether blocking glucose uptake could rescue this dysfunction. High glucose in cardiac progenitor cells results in reduced cell viability and decreased expression of cell cycle-related molecules, including CDK2 and cyclin E. A tube formation assay revealed that hyperglycemia led to a significant decrease in the tube-forming ability of cardiac progenitor cells. Fluorescent labeling of cardiac progenitor cell mitochondria revealed that hyperglycemia alters mitochondrial dynamics and increases expression of fission-related proteins, including Fis1 and Drp1. Moreover, we showed that specific blockage of GLUT1 improved cell viability, tube formation, and regulation of mitochondrial dynamics in cardiac progenitor cells. To our knowledge, this study is the first to demonstrate that high glucose leads to cardiac progenitor cell dysfunction through an increase in mitochondrial fission, and that a GLUT1 blocker can rescue cardiac progenitor cell dysfunction and downregulation of mitochondrial fission. Combined therapy with cardiac progenitor cells and a GLUT1 blocker may provide a novel strategy for cardiac progenitor cell therapy in cardiovascular disease patients with diabetes.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.4
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• pp.2301-2305
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• 2016

Background: The early detection of anthracycline- induced cardiotoxicity is very important since it might be useful in prevention of cardiac decompensation. This study was designed with the intent of assessing the usefulness of cardiac troponin T (cTnT) and NT- Pro BNP estimation in early prediction of anthracycline induced cardiotoxicity. Materials and Methods: In this prospective study histologically proven breast cancer patients who were scheduled to receive anthracycline containing combination chemotherapy as a part of multimodality treatment were enrolled. Baseline cardiac evaluation was performed by echocardiography (ECHO) and biomarkers like cardiac troponin T (cTnT) and N terminal- pro brain natriuretic peptide (NT- Pro BNP). All patients underwent cTnT and NT- Pro BNP estimation within 24 hours of each cycle of chemotherapy and were followed up after 6 months of initiation of chemotherapy. Any changes in follow up ECHO were compared to ECHO at baseline and cTnT and NT- Pro BNP levels after each cycle of anthracycline-based chemotherapy. Results: Initial data were obtained for 33 patients. Mean change in left ventricular diastolic diameter (LVDD) within 6 months was $0.154{\pm}0.433cms$ (p value=0.049). Seven out of 33 patients had an increase in biomarker cTnT levels (p value=0.5). A significant change in baseline and follow up LVDD was observed in patients with raised cTnT levels (p value=0.026) whereas no change was seen in ejection fraction (EF) and left atrial diameters (LAD) within 6 months of chemotherapy. NT- Pro BNP levels increased in significant number of patients (p value ${\leq}0.0001$) but no statistically significant change was observed in the ECHO parameters within 6 months. Conclusions: Functional monitoring is a poorly effective method in early estimation of anthracycline induced cardiac dysfunction. Estimation of biomarkers after chemotherapy may allow stratification of patients in various risk groups, thereby opening window for interventional strategies in order to prevent permanent damage to the myocardium.

• Journal of Chest Surgery
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• v.18 no.1
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• pp.1-6
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• 1985

Isolated sinus node cells of the rabbit were used to assess the effects of extracellular Na, K, Ca and Mg concentrations on cardiac pacemaker activity. With intracellular glass micro-electrodes spontaneous action potentials of SA node were recorded and the effects of various ions and their blockers were analyzed in terms of the cycle length, the amplitude and the duration of action potentials, the results obtained were as follows. 1. Sodium reduction [up to 30%] decreased the amplitude of action potential and lengthened the cycle length. TTX, specific blocker of Na channel slightly lengthened the cycle length. 2. Increasing potassium ion concentration, the duration of action potential decreased and the frequency increased in 6mM, however, spontaneous action potential was stopped in 24 mM. Barium ion known to be decreasing K conductance increased the duration of action potential but no significant change in the cycle length was noticed. 3. Calcium ion has shortening effect on the duration and the cycle length of action potential but not with dose-dependent manner. Cadmium ion .[0.02mM] lengthened cycle length and the duration of action potential. 4. Increasing the concentration of magnesium ion the cycle length was lengthened, significantly.

• Journal of Biomedical Engineering Research
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• v.23 no.6
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• pp.477-484
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• 2002

A pacemaker autosense algorithm with dual thresholds. one for noise or tachyarrhythmia detection (noise threshold, NT) and the other for intrinsic beat detection (sensing threshold. ST), was developed to improve the sensing performance in single pass VDD electrograms. unipolar electrograms, or atrial fibrillation detection. When a deflection in an electrogram exceeds the NT (defined as 50% of 57), the autosense algorithm with dual thresholds checks if the deflection also exceeds the ST. If it does, the autosense algorithm calculates the signal to noise ratio (SNR) of the deflection to the highest deflection detected by NT but lower than ST during the last cardiac cycle. If the SNR 2, the autosense algorithm declares an intrinsic beat detection and calculates the next ST based on the three most recent intrinsic peaks. If the SNR $\geq$2, the autosense algorithm checks the number of deflections detected by NT during the last cardiac cycle in order to determine if it is a noise detection or tachyarrhythmia detection. Usually the autosense algorithm tries to set the 57 at 37.5% of the average of the three intrinsic beats, although it changes the percentage according to event classifications. The autosense algorithm was tested through computer simulation of atrial electrograms from 5 patients obtained during EP study, to simulate a worst sensing situation. The result showed that the ST levels for autosense algorithm tracked the electrogram amplitudes properly, providing more noise immunity whenever necessary. Also, the autosense algorithm with dual thresholds achieved sensing performance as good as the conventional fixed sensitivity method that was optimized retrospectively.

• Journal of Biomedical Engineering Research
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• v.17 no.1
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• pp.79-84
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• 1996

A number of experimental evidences suggest that the rnun ventrolateral medulla(RVLM) is the final common pathway in the regulation of arterial blood pressure. A Voup of neurons in the RVLM, called the cardiovascular neurons (UN), show spontaneous activity temporally synchronized with the periodic cardiac cycle. These neurons affect the sympathetic nerve discharge(SND), thus are believed to be responsible for blood pressure control. The present experiment identified 98 UVNs in 42 cats based on the temporal relationships between each neuron's activity with both the cardiac cycle and SWD. In 20 UWL changes of spontaneous firing rate(FR) during the somatosympathetic reflex(SSR) were studied Five different firing patterns were observed during the pressor and depressor responses of SSR, implying that they form an interconnected neuronal circuit interacting with one another to generate efferent signals for blood pressure regulation. In the following companion paper, the firing patterns of CVN are analyzed to develop a minimal neuronal circuit model explaining the present experimental outcome.

• Journal of Biomedical Engineering Research
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• v.17 no.1
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• pp.71-80
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• 1996

A number of experimental evidences suggest that the rnun ventrolateral medulla(RVLM) is the final common pathway in the regulation of arterial blood pressure. A Voup of neurons in the RVLM, called the cardiovascular neurons (UN), show spontaneous activity temporally synchronized with the periodic cardiac cycle. These neurons affect the sympathetic nerve discharge(SND), thus are believed to be responsible for blood pressure control. The present experiment identified 98 UVNs in 42 cats based on the temporal relationships between each neuron's activity with both the cardiac cycle and SWD. In 20 UWL changes of spontaneous firing rate(FR) during the somatosympathetic reflex(SSR) were studied Five different firing patterns were observed during the pressor and depressor responses of SSR, implying that they form an interconnected neuronal circuit interacting with one another to generate efferent signals for blood pressure regulation. In the following companion paper, the firing patterns of CVN are analyzed to develop a minimal neuronal circuit model explaining the present experimental outcome.