• Journal of Chest Surgery
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• v.37 no.6
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• pp.467-473
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• 2004

Background: The sinus conversion rate after the maze procedure in chronic atrial fibrillation using radiofrequency energy is lower than with either conventional 'cut and saw' technique or cryothermia. The creation of incomplete transmural lesions due to poor tissue-catheter contact is thought to be the main cause. To address this problem, the current study was aimed to evaluate the effectiveness of a specially constructed compression device designed to enhance tissue catheter contact during unipolar radiofrequency catheter ablation. Material and Method: Circum-ferential right auricular epicardial lesions were created with a linear radiofrequency catheter in 10 anesthetized pigs. A device specially designed to increase contact by compression of the catheter to the atrial wall was used in 5 pigs (study group). This device was not used in the control group (5 pigs). Conduction block across the right auricular lesion was assessed by pacing, and the transmurality of the lesions were confirmed by microscopic examination. Result: Conduction block was observed in a total of 8 pigs; 5 in study group and 3 in control group. Transmural injury was confirmed microscopically by the accumulation of acute inflammatory cells and loss of elastic fibers in the endocardium. In two pigs with failed conduction block, microscopic examination of the endocardium appeared normal. Conclusion: Failed radiofrequency ablation is strongly related to non-transmural energy delivery. The specially constructed compression device in the current study was successful in creating firm tissue-catheter contact and thereby generating transmural lesions during unipolar radiofrequency ablation.

• Journal of Chest Surgery
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• v.38 no.5 s.250
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• pp.366-370
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• 2005

Background: In general, cardiac surgery has been performed via median sternotomy. During the past decade, improvements in endoscopic equipment and operative techniques have resulted in development of minimally invasive cardiac operation using small incisions. With the advent of a voice controlled camera-holding robotic arm (AESOP 3000, Automated Endoscope System for Optimal Positioning), cardiac surgery entered the robotic age. Material and Method: Between April 2004 and December 2004, a total of seventy eight patients underwent robotic cardiac surgery, of whom sixty four patients underwent robot-assisted minimally invasive cardiac surgery via 5cm right lateral minithoracotomy using voice controlled robotic arm, femoral vessels cannulation, percutaneous internal jugular cannulation, transthoracic aortic cross clamp. Other fourteen patients underwent MIDCAB via internal mammary artery harvesting using AESOP. Result: Robotic cardiac surgery were mitral valve repair in 37 cases, mitral valve replacement in 10 cases, aortic valve replacement in 1 case, MIDCAB in 14 cases, ASD operation in 9 cases, and isolated Maze procedure in 1 case. In mitral operation, mean CPB time was $165.3\pm43.1$ minutes and mean ACC time was $110.4\pm48.2$ minutes. Median length of hospital stay was 6 days (range 3 to 30) in mitral operation, 4 days (range 2 to 7) in MIDCAB, and 4 days (range 2 to 6) in ASD operation. For complications, 3 patients were required by reoperation for bleeding. There was no hospital mortality. Conclusion: Our experience of robot cardiac surgery suggests that many cardiovascular surgeons will be able to perform minimally invasive cardiac operations through small incisions with robot-assisted video-direction. Well-designed studies and close long-term follow-up will be required to analyze the benefits of robot-assisted operation.

• Journal of Chest Surgery
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• v.51 no.4
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• pp.266-272
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• 2018

Background: Limited comparative data are available on the efficacy of cryoablation versus radiofrequency ablation in patients with atrial fibrillation. This study aimed to compare radiofrequency ablation and cryoablation with regard to clinical outcomes and the restoration of sinus rhythm or atrial contractility. Methods: A total of 239 patients who underwent surgical ablation between August 2003 and December 2016 at our institution were included. The patients were divided into 2 groups according to the energy device that was used (group A: n=140, radiofrequency ablator; group B: n=99, cryoablator). Echocardiographic data, overall survival, and major cardiovascular and cerebrovascular event (MACCE)-free survival were compared between the 2 groups. Results: At 1 year of follow-up, the atrial contractility recovery rate was 32.2% (19 of 59) in group A and 48.8% (21 of 44) in group B. In addition, cryoablation was found to be a predictive factor for the recovery of atrial contractility (cryoablation vs. radiofrequency ablation: odds ratio, 2.540; 95% confidence interval, 1.063-6.071; p=0.036). The left ventricular ejection fraction was significantly higher in group B ($53.1%{\pm}11.5%$ vs. $59.1%{\pm}6.3%$, p=0.001). The median follow-up duration was 36 months. The 5-year overall survival rate was $80.1%{\pm}3.6%$ in group A and $92.1%{\pm}2.9%$ in group B (p=0.400). The 5-year MACCE-free survival rate was $70.3%{\pm}4.0%$ in group A and $70.9%{\pm}5.6%$ in group B (p=0.818). Conclusion: Cryoablation was associated with a higher atrial contractility restoration rate and better left ventricular function than radiofrequency ablation. However, no significant relationship was observed between the energy source and overall or MACCE-free survival.

• Journal of Microbiology and Biotechnology
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• v.27 no.11
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• pp.2044-2051
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• 2017

The main pathological hallmark of Alzheimer's disease is the deposition of amyloid-beta ($A{\beta}$) peptides in the brain. $A{\beta}$ has been widely used to mimic several aspects of Alzheimer's disease. However, several characteristics of amyloid-induced Alzheimer's disease pathology are not well established, especially in mice. The present study aimed to develop a new Alzheimer's disease model by investigating how $A{\beta}$ can be effectively aggregated using prokaryotes and eukaryotes. To express the $A{\beta}42$ complex in HEK293 cells, we cloned the $A{\beta}42$ region in a tandem repeat and incorporated the resulting construct into a eukaryotic expression vector. Following transfection into HEK293 cells via lipofection, cell viability assay and western blotting analysis revealed that exogenous $A{\beta}42$ can induce cell death and apoptosis. In addition, recombinant His-tagged $A{\beta}42$ was successfully expressed in Escherichia coli BL21 (DE3) and not only readily formed $A{\beta}$ complexes, but also inhibited the proliferation of SH-SY5Y cells and E. coli. For in vivo testing, recombinant His-tagged $A{\beta}42$ solution ($3{\mu}g/{\mu}l$ in $1{\times}PBS$ containing $1mM\;Ni^{2+}$) was injected stereotaxically into the left and right lateral ventricles of the brains of C57BL/6J mice (n = 8). Control mice were injected with $1{\times}PBS$ containing $1mM\;Ni^{2+}$ following the same procedure. Ten days after the sample injection, the Morris water maze test confirmed that exogenous $A{\beta}$ caused an increase in memory loss. These findings demonstrated that $Ni^{2+}$ is capable of complexing the 50-kDa amyloid and that intracerebroventricular injection of $A{\beta}42$ can lead to cognitive impairment, thereby providing improved Alzheimer's disease models.

• Biomolecules & Therapeutics
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• v.20 no.2
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• pp.226-233
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• 2012

Ethanol exposure during gestational period is related to growth retardation, morphological abnormality, and even in neurological abnormalities including attention deficit/hyperactivity disorder (ADHD)-like behaviors on offspring. However, relatively little is known about the effects of maternal ethanol consumption prior to conception on their offspring. In this study, we investigated whether maternal ethanol administration during preconceptional phase produces ADHD-like behaviors in the rat offspring. Sprague-Dawley (SD) female rats were administrated ethanol via intragastric intubation with dosing regimen of 6 g/kg daily for 10 consecutive days and treated female rats then mated with non-treated male SD rats after 8 weeks. Another group subjected to the same procedure as those conducted on ethanol treated group except the saline administration instead of ethanol. Offspring was tested for their ADHD-like behaviors using open field test, Y maze test and impulsivity test that is performed in the aversive electronic foot shock paradigm. Offspring of preconceptional ethanol treated (EtOH) group showed hyperlocomotive activity, attention deficit and impulsivity. And reduction of striatal dopamine transporter (DAT) level was observed by Western blot in the EtOH group, compared to control (Con) group, while the immunohistochemical analysis exhibited increased expression of norepinephrine transporter (NET) in the frontal cortex. These results suggest that maternal ethanol consumption in the preconceptional phase induces ADHD-like behaviors in offspring that might be related to the abnormal expression of DAT and NET in rat.

• Journal of Chest Surgery
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• v.38 no.7 s.252
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• pp.483-488
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• 2005

Aortic valve-sparing procedures could reduce valve-related morbidity, but may increase operative risks; therefore, these procedures could not be performed routinely. We attempted to find out the early results while focusing on the operative risks associated with these procedures in our hospital. Material and Method: From May 1996 to July 2003, 26 patients underwent these procedures including 15 patients with Marfan syndrome and 1 patient with Behcet disease. There were 17 men and 9 women with mean age of $37.9\pm19.2$ years (range: 6 months-74 years). Ten patients had ascending aortic dissection, 18 patients had more than moderate degree of aortic valve insufficiency (AI). Two types of valve-sparing procedures were performed: valve reimplantation in 14 and root remodeling in 12 patients. Associated procedures were performed as follows: aortic valve plasty in 6, mitral valve plasty in 5, hemi-arch replacement in 4, total arch replacement in 2, coronary artery bypass surgery in 1 and Maze procedure in 1 patient(s). Result: In four patients, valve-sparing procedures were converted to Bentall procedures during operation. Including these patients, there was no operative deaths, 3 patients underwent re-operation due to bleeding, 1 patient had permanent pacemaker. The median duration of ICU stay was 45.5 hours, the median duration of hospital stay was 10.5 days. In 22 patients excluding 4 converted patients, intraoperative transesophageal echocardiogram (TEE) showed less than mild degree of AI in all except one who had not received intra-operative TEE in the beginning and showed moderate degree of AI at discharge. The mean duration of follow-up was $21.2\pm27.4$ months. All patients were alive except one who died during other departmental surgery. In 3 patients, more than moderate degree of AI was recurred, but there were no reoperation. Conclusion: Aortic valve-sparing procedures could be performed relatively safely in selected patients who had annuloaortic ectasia.