Effect of Free Radicals Induced by Ultrasonic Cavitation on Cell Killing

Summary

The present study was undertaken to elucidate the mechanism of in vitro cell killing induced by 1·0 MHz continuous wave ultrasound at an intensity of 5·8 W/cm². The chemical effects and mechanical effects arising from acoustic cavitation were determined by the amount of liberated iodine and the number of DNA double-strand breaks, respectively. The survival of mouse L cells immediately after irradiation was estimated by counting the number of cells which are not stained by trypan blue and the clonogenicity of surviving cells remaining immediately after irradiation was monitored by colony-forming ability. The effectiveness of the dissolved gases in liberating iodine was in the order O₂ > Ar > N₂ > N₂O ～ 0. However, the effect of dissolved gases on the yield of double-strand breaks of DNA and on the two kinds of end points of cell killing was in the order O₂ = Ar = N₂ > N₂O ～ 0. These results suggest that the different amounts of free radicals induced by ultrasound are not directly related to the ultrasonically induced cell killing. The presence of cysteamine (2 mmol dm^?3) during sonication completely inhibited a decrease in clonogenicity of surviving cells, but did not inhibit that of cell survival immediately after sonication. These results suggest that the decrease of survival immediately after sonication is due to mechanical shear stress arising from cavitation, while the decrease of clonogenicity of the remaining surviving cells is due to free radicals induced by cavitation. The contribution of free radicals to total cell killing was estimated as about 1 per cent at the level of 95 per cent cell killing immediately after sonication.     

Left thoracotomy approach in reoperative off-pump coronary revascularization

Objective: Reoperative coronary bypass grafting is at high risk. Particularly in redo cases where the patent graft is running near the midline of the sternum, the graft may be exposed to injury by a median sternotomy and subsequent dissection. Whereas, off-pump bypass grafting from the left axillary artery or descending thoracic artery by a left thoracotomy approach is safe for preventing graft damage.Methods: From March 1998 to February 2002, we performed off-pump coronary artery bypass grafting by a left thoracotomy approach in 9 patients. The left axillary artery was used as the inflow vessel in 4 cases, and the descending thoracic, aorta in 5.Results: The radial artery was anastomosed proximally to the axillary artery in 4 cases and the descending thoracic aorta in one case. The saphenous vein graft was anastomosed, proximally to the descending thoracic aorta in 4 cases. Transdiaphragmatic minimally invasive bypass grafting for the right coronary artery was simultaneously performed in 3 cases. Postoperative cardiac events were ventricular arrhythmia in 6 cases and supraventricular arrhythmia in 3 cases. There was no damage to the patent grafts. Postoperative coronary angiography performed, in 8 cases revealed all the grafts to be patent without stenosis. Cardiac symptoms were not found after the operation in any of the cases.Conclusions: These procedures can prevent the injury to patent grafts caused by a median sternotomy, and will be one of the useful strategies for reoperative off-pump coronary artery bypass grafting.     

Left atrial maze procedure: a useful addition to other corrective operations

BACKGROUND: The left atrial maze procedure is performed to treat atrial fibrillation (AF), mainly in patients with mitral valve disease. In this study, we assessed the midterm results of this procedure and clinically analyzed predicting factors for postoperative persistent AF. METHODS: From June 1997 to May 2001, the left atrial maze procedure was performed on 31 patients (29 with mitral valve disease and 2 lone AF). For purposes of analysis, patients were divided postoperatively into those with persistent atrial fibrillation (AF) and those with sinus rhythm (SR), except 2 patients who required pacemaker implantation for sinus node dysfunction. Over a follow-up period of more than 12 months, patients were compared based on their preoperative and intraoperative variables. RESULTS: At discharge, the success rate was 89.7%. The midterm rates (total of 94.9 patient-years of follow-up) of sinus rhythm and freedom from AF were 72.4% and 79.3%, respectively. There were significant differences in duration of AF, voltage of f-wave at first precordial lead of electrocardiogram, and cardiothoracic ratio between the SR and AF groups. CONCLUSIONS: Our midterm results suggest that the left atrial maze procedure is an effective alternative adjunct procedure for elective open heart surgery to treat AF, depending upon the patient's clinical condition.     

Hydrodynamic evaluation of axillary artery perfusion for normal and diseased aorta

Axillary artery perfusion is an attractive alternative to reduce the frequency of atheroembolism in extensive atherosclerotic aorta and aortic aneurysms. This study was conducted to evaluate the flow dynamics of axillary artery perfusion. Transparent glass models of a normal aortic arch and an aortic arch aneurysm were used to evaluate hydrodynamic properties. Streamline analysis and distribution of the shear stress was evaluated using a particle image velocity method. In the normal aortic arch model, rapid flow of 80 cm/s from the right axillary artery ran out from the brachiocephalic artery and grazed the lesser curvature of the aortic arch. There was secondary reversed flow in the ascending aorta. Flow from left axillary perfusion went straight to the descending aorta. In the aortic arch aneurysm model, flow from both axillary arteries hit the lesser curvature of the aortic arch and went into the ascending aorta with vortical flow. Distribution of shear stress was high along the jet from the ostium of the brachiocephalic artery and left subclavian artery. Flow in the aortic arch and the ascending aorta was unexpectedly rapid. Special care must be taken when the patient has frail atheroma around arch vessels or the lesser curvature of the aortic arch during axillary artery perfusion.     

Bone mineral density in hypogonadal men remains low after long—term testosterone replacement

AIM: In 11 congenital hypogonadal men, the bone mineral density (BMD) values were determined to assess the effect of long-term androgen replacement therapy (ART) on skeletal integrity. METHODS: Eleven congenital hypogonadal men, including 8 isolated gonadotropin deficiency patients, 2 Kallmann's syndrome and 1 vanishing testes syndrome were recruited and treated with 250 mg of testosterone enanthate intramuscularly every 4 weeks for 7-43 years (mean+/-SD: 21.5 +/-13 years). In these patients and a group of 10 healthy young men (controls), the whole and trabecular BMDs were examined at the distal end of radius by means of a peripheral quantitative computerized tomography device. RESULTS: The whole radial BMD in hypogonadal men was significantly less in the patients than in the healthy men (498+/-115 and 725+/-134 mg/cm(3), respectively; P<0.01); the trabecular BMD was also lower in the hypogonadal men (199+/-80 and 375+/-89 mg/cm(3); P< 0.01). The whole radial BMD values in 10 of 11 hypogonadal men were at least 1 SD below the mean value for healthy young men; 2 hypogonadal men had BMD values more than 2.5 SD lower than the healthy mean. Additionally, the whole radial BMD showed a significant negative correlation with the patient's age at the initiation of ART (r = 0.748, P<0.01). The serum level of bone-specific alkaline phosphatase and the urinary level of deoxypyridinoline were not significantly different between the two groups. CONCLUSION: Osteopenia persists in the hypogonadal men after long-term ART, suggesting that such patients have a persistent defect in bone development not alleviated by androgen replacement.     

An increase in body temperature during radiofrequency ablation of liver tumors

Radiofrequency ablation (RFA) therapy using an active needle electrode inserted into liver tumors has been used clinically. To avoid hyperthermia, we investigated the relationship between the total output energy of the applied radiofrequency wave and changes in body temperature (BT) in patients receiving RFA. Fifteen patients undergoing RFA of liver tumors with general anesthesia were enrolled. The total output energy of radiofrequency waves was calculated from the power and duration of RFA. Changes in rectal (T(rect)) and tympanic temperatures were measured throughout the study. The mean number of liver tumors per patient was 1.7 +/- 1.3. The mean RFA time was 30.0 +/- 26.3 min. The mean total output energy was 125,935 +/- 114,506 J. The mean value of T(rect) increased from 36.3 degrees C +/- 0.5 degrees C to 37.0 degrees C +/- 1.0 degrees C (P < 0.01). A linear correlation was obtained between the total output energy and the changes in T(rect), indicating that T(rect) increased approximately by 1 degrees C for every 3000 J/kg of total output energy. The increase in BT during RFA of liver tumors under general anesthesia is predictable. Close observation of total output energy delivered and BT are required, and preparation of cooling measures is important, in RFA of liver tumors. IMPLICATIONS: The increase in body temperature (BT) is predictable during radiofrequency ablation (RFA) of liver tumors under general anesthesia. Close observation of total output energy delivered and BT are required, and preparation of cooling measures is important, in RFA of liver tumors.     

MIDCAB for redo patients using the LITA-RA composite graft

Redo coronary artery bypass grafting (CABG) is associated with higher mortality, low-output syndrome, perioperative myocardial infarction than primary CABG. Minimally invasive direct coronary artery bypass grafting (MIDCAB) technique avoids the manipulation of old graft and injury of the adhesive heart in redo operation. We performed the MIDCAB procedure for 2 redo cases using the left internal thoracic artery (LITA)-radial artery (RA) composite graft. The LITA-RA composite graft was anastomosed to the left anterior descending branch (LAD) through small left anterior thoracotomy without cardiopulmonary bypass. Postoperative coronary artery graphy shows the widely patent of new graft. The MIDCAB procedure using the LITA-RA composite graft is safe and useful to regulate the bypass graft length and avoid the widely harvest of LITA in redo operation.     

Meta-analysis of laparoscopic inguinal hernia trials favors open hernia repair with preperitoneal mesh prosthesis

BACKGROUND: This meta-analysis was performed to determine the degree to which improvements in open hernia repair (OHR) in the last decade have altered the relative benefit of laparoscopic hernia repair (LHR). METHODS: Twenty-seven comparative trials including 4,688 randomized patients were evaluated. RESULTS: Within the control OHR, patients with routine mesh repair returned to work earlier than a sutured repair (16.4 versus 27.3 days, P = 0.010). During the study period, the increased use of mesh in OHR (3 of 12 initially versus 9 of 15 subsequent studies) was associated with an earlier return to work (25.9 to 16.8 days, P = 0.017); there was no significant improvement with corresponding LHR. CONCLUSIONS: Although LHR was associated with an earlier return to work compared with conventional sutured OHR, more recent mesh OHRs provide equivalent outcomes but at lower costs and potentially less severe complications, supporting an open technique using preperitoneal mesh prostheses as the optimal hernia repair.     

A restricted subarachnoid hemorrhage in the cortical sulcus in cerebral amyloid angiopathy: could it be a warning sign?

BACKGROUND: Cerebral amyloid angiopathy is a well-known disease that is predominantly recognized in elderly people and repeatedly causes large subcortical hemorrhages. These hemorrhages may be derived from vessel wall weakness because of Abeta depositions in the wall of the cortical and leptomeningeal arteries. Although vessel ruptures in CAA have been thought to occur in cortical arteries, it was recently demonstrated that the primary hemorrhage occurs in the subarachnoid space, particularly the cerebral sulci, as a result of multiple ruptures of meningeal arteries in some cases of subcortical hematoma caused by CAA. CASE DESCRIPTION: Case patient 1 was a 74-year-old woman who presented with epileptic seizure. A restricted SAH in the right frontal lobe was observed on MRI. Thirty-three days later, left hemiparesis occurred suddenly and a huge subcortical hematoma was observed in the right frontal lobe on CT. The hematoma was removed, and the patient was pathologically diagnosed with amyloid angiopathy. Case patient 2 was a 73-year-old man who presented with epileptic seizure. A restricted SAH in the right frontal lobe was observed on MRI. Twenty days later, left hemiparesis occurred suddenly and a huge subcortical hematoma was observed in the right frontoparietal area on CT. Hematoma removal was performed on both patients, and they were diagnosed pathologically with amyloid angiopathy. CONCLUSIONS: We report on the cases of 2 patients with CAA who presented with epileptic seizure and were found to have a restricted subarachnoid hematoma in the cerebral sulcus on MRI before their subcortical hemorrhages occurred. Both cases were diagnosed pathologically. This demonstrated that vessel ruptures in CAA can occur in the subarachnoid space, particularly the cerebral sulci, as a result of ruptures of meningeal arteries. A restricted SAH on CT/MRI could be a warning sign of a huge subcortical hemorrhage in CAA.     

Bladder-Sparing Extended Resection of Locally Advanced Rectal Cancer Involving the Prostate and Seminal Vesicles

Purpose Total pelvic exenteration (TPE) is the standard procedure for locally advanced rectal cancer involving the prostate and seminal vesicles. We evaluated the feasibility of bladder-sparing surgery as an alternative to TPE. Methods Eleven patients with advanced primary or recurrent rectal cancer involving the prostate or seminal vesicles, or both, underwent bladder-sparing extended colorectal resection with radical prostatectomy. The procedures performed were abdominoperineal resection (APR) with prostatectomy (n = 6), colorectal resection using intersphincteric resection combined with prostatectomy (n = 4), and abdominoperineal tumor resection with prostatectomy (n = 1). Local control and urinary and anal function were evaluated postoperatively. Results Cysto-urethral anastomosis (CUA) was performed in seven patients and catheter-cystostomy was performed in four patients. Coloanal or colo-anal canal anastomosis was also performed in four patients. There was no mortality, and the morbidity rate was 38%. All patients underwent complete resection with negative surgical margins. After a median follow-up period of 26 months there was no sign of local recurrence, and ten patients were alive without disease, although distant metastases were found in three patients. Five patients had satisfactory voiding function after CUA, and three had satisfactory evacuation after intersphincteric resection (ISR). Conclusion These bladder-sparing procedures allow conservative surgery to be performed in selected patients with advanced rectal cancer involving the prostate or seminal vesicles, without compromising local control.