• Journal of Chest Surgery
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• v.35 no.3
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• pp.188-198
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• 2002

Background: Reoperations on the aortic root or the ascending aorta are being performed with increasing frequency and remain a challenging problem. This study was performed to analyze the results of reoperations on the ascending aorta and aortic root. Material and Method: Between May 1995 and April 2001, 30 patients had reoperations on the ascending aorta and aortic root and were reviewed retrospectively. The mean interval between the previous repair and the actual reoperation was 56 months(range 3 to 142 months). Seven patients(23.3%) had two or more previous operations. The indications for reoperations were true aneurysm in 7 patients(23.3%), prosthetic valve endocarditis in 6(20%), false aneurysm in 5(16.7%), paravalvular leak associated with Behcet's disease in 4(13.3%), malfunction of prosthetic aortic valve in 4(13.3%), aortic dissection in 3(10%), and annuloaortic ectasia in 1(3.3%). The principal reoperations performed were aortic root replacement in 17 patients(56.7%), replacement of the ascending aorta in 8(26.7%), aortic and mitral valve replacement with reconstruction of fibrous trigone in 2(6.6%), patch aortoplasty in 2(6.6%), and aortic valve replacement after Bentall operation in 1 (3.3%). The cardiopulmonary bypass was started before sternotomy in 7 patients and the hypothermic circulatory arrest was used in 16(53.3%). The mean time of circulatory arrest, total bypass, and aortic crossclamp were 20$\pm$ 12 minutes, 228$\pm$56 minutes, and 143$\pm$62 minutes, respectively Result: There were three early deaths(10%). The postoperative complications were reoperation for bleeding in 7 patients(23.3%), cardiac complications in 5(16.7%), transient acute renal failure in 2(6.6%), transient focal seizure in 2(6.6%), and the others in 5. The mean follow-up was 22.8 $\pm$20.5 months. There were two late deaths(7.4%). The actuarial survival was 92.6$\pm$5.0% at 6 years. One patient required reoperation for complication of reoperation on the ascending aorta and aortic root(3.7%). The 1- and 6-year actuarial freedom from reoperation was 100% and 83.3$\pm$15.2%, respectively. One patient with Behcet's disease are waiting for reoperation due to false aneurysm, which developed after aortic root replacement with homograft. There were no thromboembolisms or anticoagulant related complications. Conclusions: This study suggests that reoperations on the ascending aorta and aortic root can be performed with acceptable early mortality and morbidity, and adequate surgical strategies according to the pathologi conditions are critical to the prevention of the reoperation.

• Journal of Chest Surgery
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• v.38 no.8 s.253
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• pp.557-563
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• 2005

Background: Recently 980-nm diode laser endovenous treatment was introduced and used as a method of treatment for varicose vein in lower extremities. The advantages of endovenous laser treatment are good cosmetic effects without incision and avoidance of complications associated with surgery. Therefore, we performed an endovenous laser treatment using a 980-nm diode laser and observed the effects and the efficiency of treatment. Material and Method: From October, 2003 to March, 2004, 55 patients (84 limbs) underwent endovenous laser treatment with a 980-nm diode laser. The effects of treatment, complications and recurrences were reviewed. Result The mean age of patients was 47.2 years old and the number of men and women were 2f and 35. In a total of 84 limbs, postoperative complications were transient ecchymosis(84 cases), local paresthesia (24 cases), local skin discolorization (6 cases), minimal burn (3 cases), and post operative phlebitis (1 cases). Adjuvant sclerotherapy was performed in 27 limbs and it was performed in varicose veins missed at operation and varicose veins remaining after endovenous laser treatment. In a total of 56 patients, 2 patients $(3.57\%)$ had recurrences after endovenous laser treatment and were treated with phlebectomy. Conclusion: Our findings demonstrated that 980-nm endovenous laser treatment had good cosmetic results with acceptable complications. This study was based on short-term results and long term follow-up is necessary to evaluate the accurate effects of treatment and recurrence. We think that multimodality treatment with endovenous laser treatment including phlebectomy or transilluminated powered phlebectomy can help decreasing of recurrence especially in patients with tortuous varicose cluster.

• Journal of Chest Surgery
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• v.38 no.3 s.248
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• pp.214-220
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• 2005

Extended transseptal approach can provide an excellent view of the mitral valve but the safety of this approach is controversial because this incision requires transaction of the sinus node artery, which in most cases and can result postoperative arrhythmia. The purpose of this study was to evaluate perioperative and longterm conduction disturbances and the cardiac rhythms of patients who underwent an extended transseptal approach for mitral valve surgery. Material and Method: Postoperative cardiac rhythms were analyzed in the 164 consecutive patients who received mitral valve replacements with a extended transseptal approach between March 1992 and July 2003. Result: Of the 84 patients in normal sinus rhythm, 34 ($39\%$) had developed transient junctional rhythm and atrial fibrillation after operation, lasting less than 72 hours in most of cases. No intractable arrhythmias occurred. Most of these arrhythmia were not detected at the time of discharge and only 8 patients ($9\%$) had atrial fibrillation at discharge. Postoperative PR intervals increased for 1 week, then decreased within 2 weeks postoperatively, and returned to normal range by 6 months postoperatively. During the postoperative period, 4 of the 78 patients with preoperative atrial fibrillation developed normal sinus thythm. Conclusion: The post-operative arrhythmias were temporary and showed no significant complications after extended transseptal approach for the mitral valve surgery.

• Journal of Chest Surgery
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• v.42 no.4
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• pp.441-446
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• 2009

Background: Side clamping of ascending aorta during proximal graft anastomosis in coronary bypassing surgery in-creases the risk of direct aortic injury as well as embolization of intimal atheroma. Heartstring proximal sealing system (Guidant Corporation, Santa Clara, Calif), developed to avoid aortic side clamping, may minimize risks of such complications. The aim of the current study is to compare the surgical outcomes of the two proximal anastomosis techniquesi.e., Heartstring system versus aortic side clamping in off pump coronary bypassing' surgery (OPCAB). Material and Method: From January 2003 to August 2008, 499 patients underwent OPCAB. Of them, proximal graft anastomosis was performed using Heartstring system in 182 patients (Group I) and conventional manual anastomosis in 317 patients (Group II). The two groups were compared for postoperative major complications and mortality. Result: Two groups showed similar characteristics in terms of preoperative demographic data, left ventricular ejection fraction, renal function and history of diabetes, hypertension and smoking. Although there was no inter-group difference in the history of cerebral ischemia (p=0.48), preoperative brain magnetic resonance angiography revealed greater incidence of severe carotid artery stenosis (>75% of lumen) in the Group I than in the. Group II (44.5% in the Group I and 30.0% in the Group II, p=0.003). There were no inter-group differences in postoperative mortality (p=0.40) and complications (p=0.47) including neurologic events (3 in the Group land 2 in the Group II, p=0.258). Whereas neurologic events all comprised transient ischemic attacks in the Group I, they comprised multiple embolic strokes in the Group II. One patient in the Group II experienced aortic dissection during proximal anastomosis which resulted in ascending aortic replacement. Conclusion: Although proximal anastomosis using Heartstring system did not show statistically significant benefit over aortic side clamping, the. absence of embolic stroke maybe a definite benefit which may be better defined through further studies over a larger cohort.

• Economic and Environmental Geology
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• v.30 no.2
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• pp.137-142
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• 1997

At the tailings dam of the disused Brukunga pyrite mine in South Australia, reaction of groundwater with the tailings causes the formation and discharge of sulphuric acid. There is a need to improve remediation efforts by decreasing groundwater flow through the tailings dam. Geophysical methods have been investigated to determine whether they can be used to characterise variations in depth to watertable and map preferred groundwater flow paths. Three methods were used: transient electromagnetic (TEM) soundings, direct current (DC) soundings and profiling, and self potential (SP) profiling. The profiling methods were used to map the areal extent of a given response, while soundings was used to determine the variation in response with depth. The results of the geophysical surveys show that the voltages measured with SP profiling are small and it is hard to determine any preferred channels of groundwater flow from SP data alone. Results obtained from TEM and DC soundings, show that the DC method is useful for determining layer boundaries at shallow depths (less than about 10 m), while the TEM method can resolve deeper structures. Joint use of TEM and DC data gives a more complete and accurate geoelectric section. The TEM and DC measurements have enabled accurate determination of depth to groundwater. For soundings centred at piezometers, this depth is consistent with the measured watertable level in the corresponding piezometer. A map of the watertable level produced from all the TEM and DC soundings at the site shows that the shallowest level is at a depth of about 1 m, and occurs at the southeast of the site, while the deepest watertable level (about 17 m) occurs at the northwest part of the site. The results indicate that a possible source of groundwater occurs at the southeast area of the dam, and the aquifer thickness varies between 6 and 13 m. A map of the variation of resistivity of the aquifer has also been produced from the TEM and DC data. This map shows that the least resistive (i.e., most conductive) section of the aquifer occurs in the northeast of the site, while the most resistive part of the aquifer occurs in the southeast. These results are interpreted to indicate a source of fresh (resistive) groundwater in the southeast of the site, with a possible further source of conductive groundwater in the northeast.

• Journal of the Korean Institute of Gas
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• v.17 no.4
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• pp.58-69
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• 2013

This paper presents production data analysis for two production wells located in the shale gas field, Canada, with the proper analysis method according to each production performance characteristics. In the case A production well, the analysis was performed by applying both time and superposition time because the production history has high variation. Firstly, the flow regimes were classified with a log-log plot, and as a result, only the transient flow was appeared. Then the area of simulated reservoir volume (SRV) analyzed based on flowing material balance plot was calculated to 180 acres of time, and 240 acres of superposition time. And the original gas in place (OGIP) also was estimated to 15, 20 Bscf, respectively. However, as the area of SRV was not analyzed with the boundary dominated flow data, it was regarded as the minimum one. Therefore, the production forecasting was conducted according to variation of b exponent and the area of SRV. As a result, estimated ultimate recovery (EUR) increased 1.2 and 1.4 times respectively depending on b exponent, which was 0.5 and 1. In addition, as the area of SRV increased from 240 to 360 acres, EUR increased 1.3 times. In the case B production well, the formation compressibility and permeability depending on the overburden were applied to the analysis of the overpressured reservoir. In comparison of the case that applied geomechanical factors and the case that did not, the area of SRV was increased 1.4 times, OGIP was increased 1.5 times respectively. As a result of analysis, the prediction of future productivity including OGIP and EUR may be quite different depending on the analysis method. Thus, it was found that proper analysis methods, such as pseudo-time, superposition time, geomechanical factors, need to be applied depending on the production data to gain accurate results.

• Tuberculosis and Respiratory Diseases
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• v.47 no.3
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• pp.321-330
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• 1999

Background : Early diagnosis and proper antibiotic treatment are very important in the management of ventilator-associated pneumonia (VAP) because of its high mortality. Bronchoscopy with a protected specimen brush (PSB) has been considered the standard method to isolate the causative organisms of VAP. However, this method burdens consumer economically to purchase a PSB. Another useful method for the diagnosis of VAP is quantitative cultures of aspirated specimens through bronchoscopic bronchoalveolar lavage (BAL), for which the infusion of more than 120 m1 of saline has been recommended for adequate sampling of a pulmonary segment. However, occasionally it leads to deterioration of the patient's condition. We studied the diagnostic efficacy of minibronchoalveolar lavage (miniBAL), which retrieves only 25 ml of BAL fluid, in the isolation of causative organisms of VAP. Methods: We included 38 consecutive patients (41 cases) suspected of having VAP on the basis of clinical evidence, who had received antibiotics before the bronchoscopy. The two diagnostic techniques of PSB and miniBAL, which were performed one after another at the same pulmonary segment, 'were compared prospectively. The cut-off values for quantitative cultures to define causative bacteria of VAP were more than $10^3$ colony-forming units (cfu)/ml for PSB and more than $10^4$ cfu/ml for BAL. Results: The amount of instilled normal saline required to retrieve 25 ml of BAL fluid was $93{\pm}32 ml$ (mean${\pm}$SD). The detection rate of causative agents was 46.3% (19/41) with PSB and 43.9% (18/41) with miniBAL. The concordance rate of PSB and miniBAL in the bacterial culture was 85.4% (35/41). Although arterial blood oxygen saturation dropped significantly (p<0.05) during ($92{\pm}10%$) and 10 min after ($95{\pm}3%$) miniBAL compared with the baseline ($97{\pm}3%$), all except 3 cases were within normal ranges. The significantly elevated heart rate during ($l25{\pm}24$/min, p<0.05) miniBAL compared with the baseline ($1l1{\pm}22$/min) recovered again in 10 min after ($111{\pm}26$/min) miniBAL. Transient hypotension was developed during the procedure in two cases. The procedure was stopped in one case due to atrial flutter. Conclusion: MiniBAL is a safe and effective technique to detect the causative organisms of VAP.

• Tuberculosis and Respiratory Diseases
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• v.62 no.3
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• pp.192-196
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• 2007

Background: Right middle lobe syndrome (RMLS) is defined as transient or chronic and recurrent atelectasis of the right middle lobe. Although numerous conditions are associated with RMLS, there are very few recent reports in Korea. This study evaluated the causes of RMLS in a local tertiary hospitalover a period of 42 months. Method: Eighty-eight patients (M:F=64:22, mean age: $67.2{\pm}10.3years$), who had consistent chest radiography findings and underwent bronchoscopy in Gyeongsang University Hospital from January 2003 to July 2006, were enrolled in this study. The clinical characteristics and causes of RMLS in these patients were retrospectively reviewed. Results: The most common symptoms fo RMLS were cough, dyspnea and sputum. Tuberculosis was the most common cause (endobronchial tuberculosis in 22 and pulmonary tuberculosis in 1) The other causes were bronchial stenosis by benign fibrotic changes in 22 cases (25%), anthracofibrosis in 13 cases (14.8%), pneumonia in 11 cases (12.5%), lung cancer in 10 cases (11.4%), mucus impaction in 3 cases (3.4%), bronchiectasis in 2 cases (2.3%) and no demonstrable causes in 7 cases (8%). The bronchoscopy findings were mucosal edema with hyperemic changes in 38 cases (43.2%), mucosal edema with anthracotic pigmentation in 16 cases (18.2%), mucus impaction in 13 cases (14.8%), fibrotic stenosis in 13 cases (14.8%), a mass like lesion in 8 cases (9.1%), exudative necrotic material in 4 cases (4.5%), narrowing as a result of extrinsic compression in 2 cases (2.3%) and no demonstrable abnormalities in 12 cases (13.6%). Conclusion: Right middle lobe syndrome was observed more frequently in patients over the age of 65. The causes were mainly benign diseases with endobronchial tuberculosis being the most common.

• Applied Microscopy
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• v.30 no.4
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• pp.347-355
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• 2000

Zinc is one of the most abundant oligoelements in the living cell. It appears tightly bound to some metalloproteins and nucleic acids, loosely bound to some metallothioneins or even as free ion. Small amounts of zinc ions (in the nanomolar range) regulate a plentitude of enzymatic proteins, receptors and transcription factors, thus rolls need accurate homeostasis of zinc ions. Zinc is an essential catalytic or structural element of many proteins, and a signaling messenger that is released by neural activity at many central excitatory synapses. Growing evidences suggest that zinc may also be a key mediator and modulator of the neuronal death associated with transient global ischemia and sustained seizures, as well as perhaps other neurological disease stoles. Some neurons have developed mechanisms to accumulate zinc in specific membrane compartment ('vesicular zinc') which can be evidenced using histochemical techniques. Substances giving a bright colour or emitting fluorescence when in contact with divalent metal ions are currently used to detect them inside cells; their use leads to the so called 'direct' methods. The fixation and precipitation of metal ions as insoluble salt precipitates, their maintenance along the histological process and, finally, their demonstration after autometallographic development are essential steps for other methods, the so called 'indirect methods'. This study is a short report on the autometallograhical approaches for zinc detection in the central nervous system (CNS) by means of a modified selenium method.

• Journal of Chest Surgery
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• v.36 no.9
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• pp.659-665
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• 2003

The aim of this study was to evaluate the early and midterm results of off-pump total arterial revascularization using the skeletonized right gastroepiploic artery (RGEA) as a third arterial conduit. Material and Method: We prospectively analyzed 103 patients who underwent off-pump total arterial revascularization using bilateral internal thoracic arteries (ITAS) and RGEA. The RGEA was used as in situ graft in 88 patients, composite graft in 10 patients, and free graft in 5 patients. Postoperative coronary angiographies were performed before discharge in 100 patients, and at postoperative one year in 88 patients. Result: The RGEA showed a significantly higher free flow (130$\pm$95 ml/min) than that of right ITA(113$\pm$57 ml/min) or left ITA (107$\pm$55 ml/min), which was measured before anastomosis (p < 0.05). The total number of distal anastomoses was 3.8$\pm$0.7. The number of distal anastomoses per bilateral ITAs was 2.8$\pm$0.7 and the number of distal anastomosis per RGEA was 1.0. There were two morialities including one operative mortality. The late mortality was not related to cardiac events. Early postoperative morbidities were atrial fibrillation in 15 patients, bleeding reoperation in 4 patients, mediastinitis in 1 patients, perioperative myocardial infarction in 2 patient, and transient ARF in 3 patients. Postoperative coronary angiographies showed the early patency rate of 98.6％ (272/276) for ITAs and 97.0％ (97/100) for RGEA, respectively (p=ns), and the one-year patency rate of 95.9％ (234/244) for ITAs and 88.6％ (78/88) for RGEA, respectively (p=0.07). Flow competition between the RGEA and NCA (native coronary artery) was seen in 5 of the 100 patients (5.0％) immediate postoperatively and 7 of the 88 patients (8.0％) 1 year after surgery. Since July, 2000, we measured transit time flow intraoperatively and could reduce flow competition significantly Conclusion: The skeletonized RGEA demonstrated excellent early and midterm patency rates and could be used as a third arterial graft following the bilateral ITAs.