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Sample records for ablative maze procedure

  1. Surgical Radiofrequency MAZE III Ablation for Treatment of Atrial Fibrillation During Open Heart Surgery

    Fariborz Akbarzadeh

    2006-05-01

    Full Text Available Background: Atrial fibrillation is a common arrhythmia in patients with rheumatic mitral and other valve diseases who are candidates for valve repair surgeries. Conversion of rhythm to sinus has positive effects on quality of life and lower use of medications. The aim of this clinical study was to evaluate the effectiveness of the radiofrequency ablation Maze III procedure in the treatment of atrial fibrillation associated with rheumatic heart valve disease. Methods: We applied a modified Cox III Maze procedure using radiofrequency ablation in the treatment of atrial fibrillation associated with rheumatic heart valve disease and evaluated the outcome of 20 patients of atrial fibrillation associated rheumatic valve disease who underwent radiofrequency ablation Maze III procedure plus heart valve surgery. Demographic, echocardiographic, Electrocardiographic and Doppler study data were calculated before surgery, six month and one year after surgery.. Results: No perioperative deaths occurred in the study group. Duration of additional time for doing radiofrequency ablation was about 22 minutes. Freedom from atrial fibrillation was 85% and 75% at six months and one year follow-up respectively... Conclusions: The addition of the radiofrequency ablation Maze procedure to heart valve surgery is safe and effective in the treatment of atrial fibrillation associated with rheumatic heart valve disease.

  2. Postoperative metabolic acidosis following the minimally invasive radiofrequency maze procedure

    Raymond Patrick Hom

    2016-01-01

    Full Text Available Purpose: Atrial fibrillation (AF is the most common arrhythmia treated in the world. While medical treatment with antiarrhythmic drugs remains the primary treatment modality, symptomatic refractory AF often requires treatment with a catheter or surgical ablation. One minimally invasive therapy is the Mini-Maze procedure, which utilizes epicardial radiofrequency ablation via a subxiphoid approach to rid the heart of arrhythmogenic atrial foci without a median sternotomy or cardiopulmonary bypass. The goal of this retrospective cohort study was to identify clinical factors associated with metabolic acidosis following the Mini-Maze procedure. Materials and Methods: After Institutional Review Board approval, we studied patients undergoing the Mini-Maze procedure, off-pump coronary artery bypass grafting or patients conventional Cox-Maze on cardiopulmonary bypass. The first base deficit value obtained in the Intensive Care Unit was used as a measure of metabolic acidosis. Using logistic regression with Akaike information criteria, we analyzed preoperative, intraoperative, and postoperative data to determine the factors associated with changes in base deficit. Results: A multivariable model using stepwise selection demonstrated that diabetes mellitus and weight were associated with a decrease in the base deficit by 2.87 mEq/L (95% CI: −5.55-−0.19 and 0.04 mEq/L (95%CI: −0.08, 0.004, respectively. Furthermore, creatinine was associated with a 1.57 mEq/L (95% CI: 0.14, 2.99 increase in the base deficit. Conclusion: The Mini-Maze procedure was not associated with postoperative metabolic acidosis. Instead, nondiabetic patients and patients with higher creatinine were associated with greater base deficits after undergoing cardiac surgery.

  3. Robotic excision of aortic valve papillary fibroelastoma and concomitant Maze procedure

    Edward T Murphy

    2012-12-01

    Full Text Available Cardiothoracic surgeons have utilized the surgical robot to provide a minimally invasive approach to a number of intracardiac operations, including tumor resection, valve repair, and ablation of atrial arrhythmia. We report the case of a 58 year-old woman who was found to have a mobile mass on her aortic valve during evaluation of atrial fibrillation. Both of these conditions were addressed when she underwent a combined robotic biatrial Maze procedure and excision of the mass, which proved to be a papillary fibroelastoma of the aortic valve.

  4. 风湿性心脏瓣膜置换术同期射频消融迷宫术治疗房颤%Intraoperative modified maze procedure by radiofrequency ablation to treat atrial fibrillation during concomitant valve replacement of rheumatic heart disease

    雷虹; 严中亚; 严宇; 朱正艳

    2012-01-01

    Objective To analyze the effectiveness of modified maze procedure by radiofrequency ablation in the patients of valvular heart diseases with atrial fibrillation ( AF ) who underwent heart valve replacement surgery. Methods 11 cases of valvular heart diseases with AF undergoing modified maze procedure by radiofrequency ablation with concomitant Valve Replacement during March 2010 to November 2011 were investigated. Including 1 case of double valvular replacement ,10 cases of mitral valvular replacement, four of them with tricuspid valve annuloplasty. Results 11 cases resumed sinus rhythm immediately after the surgery. 1 cf them is sinus bradycardia, another case is ventricular tachycardia Ⅲ0 atrial - ventricular block and atrial muscle perforation did not occurr. 1 patient occurred death. With 3 ~ 12 months follow - up. 10 patients remained in sinus rhythm. One patient had atrial fibrillation recurrence after 6 months. And the left atriums of the remaining 10 patients were significantly reduced. Conclusion Valve replace operation combined with radiofrequency modified maze procedure in the treatment of atrial fibrillation with valvular heart disease is safe and worth popularizing.%目的 对合并房颤的心脏瓣膜病患者行瓣膜置换手术的同时进行射频改良迷宫Ⅲ手术,评价风湿性心脏瓣膜置换术同期射频消融迷宫术治疗房颤的临床效果.方法 2010 年3 月至2011 年11 月,采用Medtronic公司的射频消融系统对11例合并房颤的心脏瓣膜病患者行瓣膜置换手术的同时进行射频改良迷宫Ⅲ手术,其中包括双瓣置换术1例、二尖瓣置换术10例同时三尖瓣成形术4例.结果 术毕转为窦性心律11 例,1例窦性心动过缓,1例室速,无Ⅲ°房室传导阻滞,无心房穿孔出血,1例术后低心排死亡,随访3~12个月,10例均为窦性心律,1例术后6个月出现房颤复发,余10例患者超声心动图检查左房明显缩小.结论 射频消融改良迷宫Ⅲ手术在

  5. Results of clinical application of the modified maze procedure as concomitant surgery

    R.C. Bakker (Robbert); S. Akin (Sakir); D. Rizopoulos (Dimitris); C. Kik (Charles); J.J.M. Takkenberg (Hanneke); A.J.J.C. Bogers (Ad)

    2013-01-01

    textabstractObjectives Atrial fibrillation is the most common cardiac arrhythmia and is associated with significant morbidity and mortality. The classic cut-and-sew maze procedure is successful in 85-95% of patients. However, the technical complexity has prompted modifications of the maze procedure.

  6. DSTYK kinase domain ablation impaired the mice capabilities of learning and memory in water maze test.

    Li, Kui; Liu, Ji-Wei; Zhu, Zhi-Chuan; Wang, Hong-Tao; Zu, Yong; Liu, Yong-Jie; Yang, Yan-Hong; Xiong, Zhi-Qi; Shen, Xu; Chen, Rui; Zheng, Jing; Hu, Ze-Lan

    2014-01-01

    DSTYK (Dual serine/threonine and tyrosine protein kinase) is a putative dual Ser/Thr and Tyr protein kinase with unique structural features. It is proposed that DSTYK may play important roles in brain because of its high expression in most brain areas. In the present study, a DSTYK knockout (KO) mouse line with the ablation of C-terminal of DSTYK including the kinase domain was generated to study the physiological function of DSTYK. The DSTYK KO mice are fertile and have no significant morphological defects revealed by Nissl staining compared with wildtype mice. Open field test and rotarod test showed there is no obvious difference in basic motor and balance capacity between the DSTYK homozygous KO mice and DSTYK heterozygous KO mice. In water maze test, however, the DSTYK homozygous KO mice show impaired capabilities of learning and memory compared with the DSTYK heterozygous KO mice.

  7. Analyze the effectiveness of modified maze procedure by irrigated radiofrequency ablation in the 144 patients with valvular heart disease and atrial fibrillation who underwent surgical operation%144例心脏瓣膜病合并心房颤动外科手术同期行单极冲洗射频消融改良迷宫术的疗效

    王嬿; 胡大清

    2012-01-01

    目的 分析本院心脏瓣膜病伴发心房颤动(简称房颤)的患者外科手术同期行单极冲洗射频消融改良迷宫术MazeⅢ型手术疗效.方法 调查2007年11月至2010年8月收治的心脏瓣膜病合并房颤患者在心内直视手术下同期行单极冲洗射频消融改良迷宫术MazeⅢ型手术,观察随访6个月时的心律情况,根据节律分为窦性心律(简称窦律)组和非窦律组,分析影响术后转律的原因.结果 144例入选,2例安置永久起搏器,1例因瓣周漏而行二次手术.出院时窦律88例(61.11%),房颤39例(27.08%),随访6个月窦律88例(61.11%),房颤25例(17.36%).窦律组左房小于非窦律组,房颤时间短于非窦律组.左房内径≥6.5 cm者,可达龙的转复率高于非可达龙组(53.8% vs 28.6%,P<0.05).结论 心脏病伴发房颤的病人,在心脏外科手术中同期行单极冲洗射频消融改良迷宫术,对窦律的恢复仍不失为一种安全有效的方法.术前左房内径大小及房颤持续时间是房颤转复的主要危险因素,可达龙在一定程度上可提高大左房(≥6.5 cm)的转复成功率.%Objective To analyze the effectiveness of modified maze procedure by irrigated radiofrequeney ablation in the patients of valvular heart diseases with atriai fibrillation ( AF) who underwent open-heart surgery. Methods All the cases of valvular heart diseases with AF undergoing modified maze procedure by irrigated radioirequency ablation with concomitant open-heart surgery during November 2007 to August 2010 were investigated. All the patients were followed up for 6 months and divided into two groups:sinus-rhythm group and non-sinus-rhythm group according to the rhythm. Analyze the influencing factors of the rhythm. Results One hundred and forty-four cases were collected,2 cases were implanted permanent pacemakers,1 case was re-operated because of paravalvulur leak,88 cases were recorded sinus rhythm and 39 remained in AF when discharged from

  8. Perioperative nursing of modified maze procedure using bipolar radiofrequency ablation accompanied with valve replacement for surgical treatment of permanent atrial fibrillation%心脏瓣膜置换术同期双极射频消融治疗永久性心房颤动的围手术期护理

    洪慧; 陈晓玲; 石开虎

    2013-01-01

    目的 探讨心内直视下同期行改良冲洗式双极射频消融治疗心瓣膜病合并永久性心房颤动的围手术期护理要点.方法 回顾性分析2010年6月至2013年2月心脏瓣膜病合并永久心房颤动55例患者在体外循环下行心瓣膜置换术+改良冲洗式双极射频消融手术的临床资料.55例患者均合并永久性心房颤动,术前给予患者心理护理及健康宣教,术中采用Medtronic Cardioblate 68000冲洗式双极射频消融系统进行消融操作,术后除做好瓣膜置换术后常规护理外,重视心律和心率的监测,心功能的维护,引流的观察,电解质平衡的维持,起搏器的观察,应用胺碘酮的观察及护理,以及健康指导与心理护理.结果 55例手术均顺利完成,术后当天有48例恢复为窦性心律.全组2例出现Ⅲ度房室传导阻滞,安装永久起搏器治疗,全组无心脏穿孔及术后大出血,无手术死亡.平均住院(12.5± 2.1)d,术后平均随访(8.6±3.0)个月,87.3%的患者维持窦性心律,9.1%的患者为房颤心律,3.6%的患者为起搏心律.结论 心内直视下同期改良冲洗式双极射频消融治疗心脏瓣膜病合并永久性心房颤动是一种简易、安全、有效的方法,高质量的围手术期护理是提高手术成功率,降低死亡率的关键.%Objective To summarize the perioperative nursing of modified maze procedure using bipolar radiofrequency ablation accompanied with valve replacement for the surgical treatment of heart valve diseases complicated with permanent atrial fibrillation (AF).Methods A total of 55 patients with permanent AF and heart valves diseases were undergone surgical treatment from June 2010 to February 2013 in the Second Affiliated Hospital of Anhui Medical University.Preoperative psychological care and health education were given to patients.The Medtronic Cardioblate 68000 flush bipolar radiofrequency ablation system was applied to all patients.After valve replacement

  9. Modified Maze lines plus pulmonary vein isolation created by radiofrequency catheter ablation on the atrial wall to treat atrial fibrillation in elderly

    Caiyi LU; Shiwen WANG; Xinping DU; Yinglong HOU; Qiao XUE; Xinli WU; Rui CHEN; Peng LIU

    2005-01-01

    Objective To evaluate the effect of modified Maze lines plus pulmonary vein (PV) isolation created by radiofrequency catheter ablation (RFCA) on atrial wall guided by a novel geometry mapping system in the treatment of elderly patients with paroxysmal atrial fibrillation (PAF). Methods After regular electrophysiological study, transseptal punctures were achieved twice with Swartz L1 and R1 sheaths. PV angiographies were conducted to evaluate their orifices and branches. A balloon electrode array catheter with 64 electrodes was put in the middle of the left atrium. Atrium geometry was constructed using Ensite 3000 Navx system. Two RFCA lesion loops and three lines (modified Maze) were created on left and right atrial walls. Each lesion point was ablated for 30 seconds with preset temperature 50 (ae) and energy 30W. The disappearance or 80% decrease of the amplitude of target atrial potential and 10 to 20(|), decrease of ablation impedance were used as an index of effective ablation. Results A total of 11 patients (7 male and 4 female, mean age, 68.7±5.1 years) were enrolled. PAF history was 7.9±4.5 years. PAF could not be prevented by mean 3.1±1.6 antiarrhythmic agents in 6.3±3.4 years. None of the patients had complications with structural heart disease or stroke. Left atrial diameter was 41.3±3.6 mm and LVEF was 59.2±3.7% on echocardiography. Two loops and three lines were completed with 67.8±13.1 (73-167) lesion points. Altogether 76-168 (89.4±15.3) lesion points were created in each patient. PAF could not be provoked by rapid burst pacing up to 600 beat per minute delivered from paroxysmal coronary sinus electrode pair.Complete PV electrical isolation was confirmed by three-dimensional activation mapping. Mean procedure time was 2.7±0.6 hours and fluoroscopy time was 17.8±9.4 minutes. Patients were discharged with oral aspirin and without antiarrhythmic agents. During follow up of 6.5±1.8 months, seven patients were PAF symptom free (63.6%). PAF

  10. Radiofrequency ablation of hepatic tumors: lessons learned from 3000 procedures.

    Rhim, Hyunchul; Lim, Hyo K; Kim, Young-sum; Choi, Dongil; Lee, Won Jae

    2008-10-01

    Radiofrequency ablation has been accepted as the most popular local ablative therapy for unresectable malignant hepatic tumors. For 9 years from April 1999, we performed 3000 radiofrequency ablation procedures for hepatic tumors in our institution. Our results on the safety (mortality, 0.15%/patient) and therapeutic efficacy (5-year survival rate, 58%) are similar to those of previous studies reported, supporting the growing evidence of a clear survival benefit, excellent results for local tumor control and improved quality of life. The most important lesson learned from our 3000 procedures is that the best planning, safe ablation and complete ablation are key factors for patient outcome. Furthermore, multimodality treatment is the best strategy for recurrent hepatocellular carcinoma encountered after any kind of first-line treatment.

  11. The effects of apparatus design and test procedure on learning and memory performance of C57BL/6J mice on the Barnes maze.

    O'Leary, Timothy P; Brown, Richard E

    2012-01-30

    The Barnes maze is a visuo-spatial learning and memory test originally designed for use with rats, and later adapted for use with mice. The Barnes maze design and test procedure vary across studies using mice, but the effects of variation in Barnes maze design and test procedure on learning and memory in mice have not yet been investigated. Therefore the present experiment investigates whether test procedures, such as the number of habituation trials and parameters of the probe trial (correct zone size and trial length) influence learning and memory performance on three Barnes maze designs that differed in size and the presence of a wall with intra-maze visual cues. Performance was compared across the three mazes to determine how apparatus design influences visuo-spatial cue use. The number of habituation trials and parameters of the probe trial had small effects on learning and memory performance. Apparatus design, had little effect on acquisition performance but had a significant effect on memory performance. Mice on a maze with a small diameter, external wall and intra-maze visual cues had very poor visuo-spatial memory relative to mice tested on small and large diameter mazes without a wall or intra-maze visual cues. Assessment of visuo-spatial cue use indicated that mice do not rely on visuo-spatial cues to locate the escape hole on the small-diameter maze with a wall and intra-maze visual cues, but show reliable visuo-spatial cue use on small or large diameter mazes with no wall. These results indicate that apparatus design influences search strategy use and memory performance on the Barnes maze, and that including a wall around the edge of the Barnes maze decreases visuo-spatial cue use.

  12. Optimizing safety and efficacy of catheter ablation procedures

    F. Akca (Ferdi)

    2015-01-01

    markdownabstractAbstract In this thesis new developments in the field of invasive electrophysiology are studied and discussed. The aim of this work is to find strategies to optimize safety and efficacy of catheter ablation procedures. The most important developments that are studied in this thesis

  13. Cox-Maze III procedure with valvular surgery in an autopneumonectomized patient

    Wi Jin

    2012-11-01

    Full Text Available Abstract Destructive pulmonary inflammation can leave patients with only a single functional lung, resulting in anatomical and physiological changes that may interfere with subsequent cardiac surgeries. Such patients are vulnerable to perioperative cardiopulmonary complications. Herein, we report the first case, to our knowledge, of an autopneumonectomized patient who successfully underwent a modified Cox-Maze III procedure combined with valvular repairs. The three major findings in this case can be summarized as follows: (1 a median sternotomy with peripheral cannulations, such as femoral cannulations, can provide an optimal exposure and prevent the obstruction of vision that may occur as a result of multiple cannulations through a median sternotomy; (2 a modified septal incision combined with biatrial incisions facilitate adequate exposure of the mitral valve; and (3 the aggressive use of intraoperative ultrafiltration may be helpful for the perioperative managements as decreasing pulmonary water contents, thereby avoiding the pulmonary edema associated with secretion of inflammatory cytokines during a cardiopulmonary bypass. We also provide several suggestions for achieving similar satisfactory surgical outcomes in patients with a comparable condition.

  14. Induction of habits in rats by a forced-choice procedure in T-maze and the effect of pre-test free exploration

    Moustgaard, Anette; Hau, Jann

    2009-01-01

    A forced-choice procedure in T-maze designed for the induction of habits was used to induce strong habits in rats. The response choices of rats in 20 free-choice trials were compared after the rats had been subjected to 1 or 200 forced-choice trials to one side of the T-maze. After 200 forced-cho...

  15. Sinus node function after cardiac surgery : is impairment specific for the maze procedure?

    Tuinenburg, AE; Van Gelder, IC; Van Den Berg, MP; Grandjean, JG; Tieleman, RG; Smit, AJ; Huet, RCG; Van Der Maaten, JMAA; Volkers, CP; Ebels, T; Crijns, HJGM

    2004-01-01

    Background: Maze surgery is a final solution for intractable atrial fibrillation (AF), but an adverse effect on postoperative sinus node function has been reported. Whether this also applies to other types of cardiac surgery is unclear. Methods: We assessed postoperative rhythm by means of repeated

  16. Individual housing and handling procedures modify anxiety levels of Tg2576 mice assessed in the zero maze test.

    Heredia, Luis; Torrente, Margarita; Domingo, José L; Colomina, María T

    2012-09-10

    The zero maze is an unconditioned anxiety test for mice, in which a number of environmental variables can modify the anxiety levels of the animals. In the present study, we have assessed how individual housing, handling procedure and interaction between individual housing and handling procedure affect the baseline anxiety of mice. Thirty-seven wild type mice and eighteen Tg2576 mice were used (obtained from crossing APPSWE hemizygous male C57BL6/SJL background with C57BL6/SJL female). Wild type mice were randomly assigned to four experimental groups: 1) group housed and unhandled, 2) group housed but handled, 3) individually housed, unhandled, and 4) individually housed and handled. In turn, Tg2576 mice were randomly assigned to two experimental groups: 1) individually housed, unhandled, and 2) individually housed and handled. The results show that individually housed mice exhibited more anxiety-related behaviors over a 5 min testing period than the other experimental groups. Use of the handling procedure was associated with a statistically significant reduction in anxiety-related behaviors among individually housed mice. No effects on anxiety-related behavior levels were observed when group housed animals were handled. When activity levels were significantly increased, a new parameter, "Time by Entries", helped to prevent activity from influencing anxiety parameters such as time in the open section of the zero maze test. This knowledge can help to design more efficient experiments without bias from data obtained by means of unconditioned tests.

  17. Validation and scopolamine-reversal of latent learning in the water maze utilizing a revised direct platform placement procedure.

    Malin, David H; Schaar, Krystal L; Izygon, Jonathan J; Nghiem, Duyen M; Jabitta, Sikirat Y; Henceroth, Mallori M; Chang, Yu-Hsuan; Daggett, Jenny M; Ward, Christopher P

    2015-08-01

    The Morris water maze is routinely used to explore neurobiological mechanisms of working memory. Humans can often acquire working memory relevant to performing a task by mere sensory observation, without having to actually perform the task followed by reinforcement. This can be modeled in the water maze through direct placement of a rat on the escape platform so that it can observe the location, and then assessing the subject's performance in swimming back to the platform. However, direct placement procedures have hardly been studied for two decades, reflecting a controversy about whether direct placement resulted in sufficiently rapid and direct swims back to the platform. In the present study, utilizing revised training methods, a more comprehensive measure of trajectory directness, a more rigorous sham-trained control procedure and an optimal placement-test interval, rats swam almost directly back to the platform in under 4s, significantly more quickly and directly than sham-trained subjects. Muscarinic cholinergic mechanisms, which are inactivated by scopolamine, are essential to memory for standard learning paradigms in the water maze. This experiment determined whether this would also be true for latent learning. ANOVA revealed significant negative effects of scopolamine on both speed and accuracy of trajectory, as well as significant positive effects of direct placement training vs. sham-training. In a probe trial, placement-trained animals without scopolamine spent significantly more time and path length in the target quadrant than trained rats with scopolamine and sham-trained rats without scopolamine. Scopolamine impairments are likely due to effects on memory, since the same dose had little effect on performance with a visible platform. The revised direct placement model offers a means of further comparing the neural mechanisms of latent learning with those of standard instrumental learning.

  18. [Maze procedure in a case of dextrocardia with atrial septal defect and persistent left superior vena cava].

    Muraoka, Arata; Kawada, Masaaki; Misawa, Yoshio

    2014-08-01

    A 52-year-old man was diagnosed with dextrocardia at the age of 1 year and was asymptomatic until 1 year before admission. He was transferred to our hospital for management of atrial fibrillation. A transthoracic echocardiogram showed dextrocardia with atrial septal defect;moderate tricuspid valve regurgitation; and a large, persistent left superior vena cava. A cardiac catheterization study revealed that pulmonary flow/systemic flow (Qp/Qs) was 3.6 and that pulmonary vascular resistance was 2.5 Wood U·m². Intracardiac repair with tricuspid annuloplasty and a maze procedure was scheduled. When establishing cardiopulmonary bypass, venous drainage was initially obtained from the inferior vena cava and the left superior vena cava, and the small superior vena cava was then directly cannulated after opening the right atrium. The patient's postoperative course was uneventful, and serial electrocardiograms have demonstrated maintenance of normal sinus rhythm for 3.5 years after the operation.

  19. Effect of a water-maze procedure on the redox mechanisms in brain parts of aged rats.

    Krivova, Natalia A; Zaeva, Olga B; Grigorieva, Valery A

    2015-01-01

    The Morris water maze (MWM) is a tool for assessment of age-related modulations spatial learning and memory in laboratory rats. In our work was investigated the age-related decline of MWM performance in 11-month-old rats and the effect exerted by training in the MWM on the redox mechanisms in rat brain parts. Young adult (3-month-old) and aged (11-month-old) male rats were trained in the MWM. Intact animals of the corresponding age were used as the reference groups. The level of pro- and antioxidant capacity in brain tissue homogenates was assessed using the chemiluminescence method. A reduced performance in the MWM test was found in 11-month-old rats: at the first day of training they showed only 30% of successful MWM trials. However, at the last training day the percentage of successful trials was equal for young adult and aged animals. This indicates that the aged 11-month-old rats can successfully learn in MWM. Therewith, the MWM spatial learning procedure itself produces changes in different processes of redox homeostasis in 11-month-old and 3-month-old rats as compared to intact animals. Young adult rats showed a decrease in prooxidant capacity in all brain parts, while 11-month-old rats demonstrated an increase in antioxidant capacity in the olfactory bulb, pons + medulla oblongata and frontal lobe cortex. Hence, the MWM procedure activates the mechanisms that restrict the oxidative stress in brain parts. The obtained results may be an argument for further development of the animal training procedures aimed to activate the mechanisms that can prevent the age-related deterioration of performance in the learning test. This may be useful not only for the development of training procedures applicable to human patients with age-related cognitive impairments, but also for their rehabilitation.

  20. Intermittent swim stress causes Morris water maze performance deficits in a massed-learning trial procedure that are exacerbated by reboxetine.

    Warner, Timothy A; Stafford, Nathaniel P; Rompala, Gregory R; Van Hoogenstyn, Andrew J; Elgert, Emily; Drugan, Robert C

    2013-11-15

    Various animal models of depression have been used to seek a greater understanding of stress-related disorders. However, there is still a great need for research in this area, as many unanswered questions remain. Therefore, we sought to employ a novel animal model of depression known as intermittent swim stress (ISS). In this model, the animal experiences 100 trials of cold water swim stress. ISS has already shown subsequent immobility in the forced swim test (FST), deficits in instrumental and spatial (spaced-trial procedure), and responsiveness to norepinephrine. We are now examining how this will translate in the Morris water maze for rats in a massed-learning trial procedure, and further assessing ISS sensitivity toward norepinephrine selective anti-depressant drugs. The results indicated no difference in cued learning when the platform was visible in the water maze, but a hidden platform task revealed poorer spatial learning for ISS-exposed rats versus controls. In terms of spatial memory, there was a notable ISS-induced deficit 1h after the learning trials, regardless of performance on the previous platform task. Interestingly, the administration of reboxetine interfered with the spatial learning and memory trials for both ISS and CC groups. As a result, ISS exposure compromised spatial learning and memory in the Morris water maze, and norepinephrine does not appear to be a mediator of this deficit. The results demonstrate a key difference in the effects of reboxetine in a massed- vs. spaced-learning trial procedure in the Morris water maze following ISS exposure.

  1. Intermittently “Pre-Excited” ECG after Accessory Pathway Ablation: Unsuccessful Procedure or a Complication?

    Evgeny Mikhaylov

    2012-01-01

    Full Text Available A 52-year-old woman with previously unsuccessful posteroseptal pathway ablation using radiofrequency energy presented with intermittently occurring short PR followed by a wide QRS complex, and complaining of palpitations with characteristics different from previous history. During a second electrophysiological procedure no signs of preexcitation were found. Ventricular discharges with fusion with sinus beats were revealed, and catheter ablation of premature contractions originating from the proximity to previous accessory pathway was carried out.

  2. Anesthetic Considerations for a Patient With Hereditary Hemorrhagic Telangiectasia (Osler–Weber–Rendu Syndrome Undergoing a Five-Box Thoracoscopic Maze Procedure for Atrial Fibrillation

    Dominic Robinson DO

    2014-10-01

    Full Text Available Hereditary hemorrhagic telangiectasia (HHT is an autosomal dominant genetic disorder involving the abnormal communication of vascular structures. HHT typically presents with recurrent epistaxis and telangiectasis of the nasal and buccal mucosa, tongue, and lips. More serious manifestations of this disease include cerebral, pulmonary, gastrointestinal, and hepatic arteriovenous malformations. This case report details a 55-year-old male with HHT undergoing a five-box maze procedure for curative treatment of atrial fibrillation. Particular anesthetic considerations are described to reduce morbidity and mortality in this patient population.

  3. X-ray exposure hazards for physicians performing ablation procedures and device implantation

    Marinskis, Germanas; Bongiorni, Maria Grazia; Dagres, Nikolaos

    2013-01-01

    The purpose of the survey was to evaluate physician's and authorities policies and clinical practices when using occupational X-ray during ablation procedures and device implantation. This survey shows infrequent use of lead gloves, radiation absorbing pads, and lead glass cabins, but increasing ...

  4. Case report of surgical treatment of abnormal atrial flutter (incisional atrial tachycardia in the patient after mitral valve replacement and radiofrequency modification of Maze procedure

    Revishvili А. Sh.

    2012-12-01

    Conclusion. This type of tachycardia following after an atrial fibrillation surgery may be considered as a failing transmural myocardial damage during the procedure. The catheter method can be used succesfully unless there are no effects of antiarrhythmic therapy. The catheter method enables not only to verify the disconnection between the left atrial pulmonary veins and left atrium myocardium but also to perform the ablation in zones of the atrial myocardium that are anatomic substrates of post surgery tachyarrhythmias.

  5. Radiofrequency ablation of chondroblastoma: procedure technique, clinical and MR imaging follow up of four cases

    Christie-Large, M.; Evans, N.; Davies, A.M.; James, S.L.J. [Royal Orthopaedic Hospital Foundation Trust, Department of Radiology, Birmingham (United Kingdom)

    2008-11-15

    The aim of this study is to describe the procedure technique, clinical and imaging outcomes of patients treated with radiofrequency ablation for chondroblastoma. Four patients (female/male, 3:1; mean age, 13 years; age range; 9-16 years) underwent the procedure. All had pre-operative magnetic resonance imaging (MRI) and symptomatic, biopsy-proven chondroblastomas (two proximal femur, two proximal tibia). The lesion size ranged from 1.5 to 2.5 cm in maximal dimension (mean size, 1.8 cm). Bone access was gained with a Bonopty biopsy needle system (mean number of radiofrequency needle placements, 5; mean ablation time, 31 min). Clinical and MRI follow-up was available in all cases (mean, 12.25 months; range, 5-18 months). All patients reported resolution of symptoms at 2-6 weeks post ablation. At their most recent clinical follow-up, three patients remained completely asymptomatic with full return to normal activities and one patient had minor local discomfort (different pain pattern) that was not limiting activity. All four patients' follow-up MRI studies demonstrated resolution of the oedema pattern around the lesion and temporal evolution of the internal signal characteristics with fatty replacement. Radiofrequency ablation for chondroblastoma provides an alternative to surgical curettage, and we have demonstrated both a clinical improvement in symptoms and the follow-up MRI appearances. (orig.)

  6. Ablation of an atriofascicular accessory pathway with a zero-fluoroscopy procedure

    PROIETTI, RICCARDO; Abadir, Sylvia; Bernier, Martin L.; Essebag, Vidal

    2015-01-01

    A 16-year-old patient with recurrent palpitations and documented left bundle branch block superior axis wide complex tachycardia underwent an electrophysiological study and ablation with a zero-fluoroscopy procedure. The electrophysiological study showed a decremental antegrade conducting atriofascicular pathway. Three-dimensional CARTO-guided mapping of the tricuspid annulus in sinus rhythm was performed, and a distinct signal corresponding to the accessory pathway potential of the atriofasc...

  7. Clinical Outcomes of an Optimized Prolate Ablation Procedure for Correcting Residual Refractive Errors Following Laser Surgery

    Chung, Byunghoon; Lee, Hun; Choi, Bong Joon; Seo, Kyung Ryul; Kim, Eung Kwon; Kim, Dae Yune

    2017-01-01

    Purpose The purpose of this study was to investigate the clinical efficacy of an optimized prolate ablation procedure for correcting residual refractive errors following laser surgery. Methods We analyzed 24 eyes of 15 patients who underwent an optimized prolate ablation procedure for the correction of residual refractive errors following laser in situ keratomileusis, laser-assisted subepithelial keratectomy, or photorefractive keratectomy surgeries. Preoperative ophthalmic examinations were performed, and uncorrected distance visual acuity, corrected distance visual acuity, manifest refraction values (sphere, cylinder, and spherical equivalent), point spread function, modulation transfer function, corneal asphericity (Q value), ocular aberrations, and corneal haze measurements were obtained postoperatively at 1, 3, and 6 months. Results Uncorrected distance visual acuity improved and refractive errors decreased significantly at 1, 3, and 6 months postoperatively. Total coma aberration increased at 3 and 6 months postoperatively, while changes in all other aberrations were not statistically significant. Similarly, no significant changes in point spread function were detected, but modulation transfer function increased significantly at the postoperative time points measured. Conclusions The optimized prolate ablation procedure was effective in terms of improving visual acuity and objective visual performance for the correction of persistent refractive errors following laser surgery. PMID:28243019

  8. Early Heparin Administration Reduces Risk for Left Atrial Thrombus Formation during Atrial Fibrillation Ablation Procedures

    Stefan Asbach

    2011-01-01

    Full Text Available Objective. Despite the use of anticoagulation during left atrial (LA ablation procedures, ischemic cerebrovascular accidents (CVAs are recognized as a serious complication. Heparin is usually given after safe transseptal access has been obtained, resulting in a short unprotected dwell time of catheters within the LA, which may account for CVAs. We investigated the frequency of CVAs and LA thrombus formation as detected by intracardiac ultrasound (ICE depending on the timing of heparin administration. Methods and Results. Sixty LA ablation procedures with the use of ICE were performed in 55 patients. Patients were grouped by heparin administration after (Group I, =13 and before (Group II, =47 transseptal access. Group I patients were younger (56.6±13.7 versus 65.9±9.9 years, =.01; other clinical and echocardiographic characteristics did not differ between groups. Early thrombus formation was observed in 2 (15.4% of group I patients as compared to 0% of group II patients (=.04. One CVA (2.1% occurred in one group II patient without prior thrombus detection, and none occurred in group I patients (=ns. Conclusion. Early administration of heparin reduces the risk of early intracardiac thrombus formation during LA ablation procedures. This did not result in reduced rate of CVAs.

  9. Catheter Ablation

    ... ablation. Visit Cardiac ablation procedures and Cardiac conduction system for more information about this topic. Related ... National Institutes of Health Department of Health and Human Services USA.gov

  10. Ablation of an atriofascicular accessory pathway with a zero-fluoroscopy procedure

    Proietti, Riccardo; Abadir, Sylvia; Bernier, Martin L.; Essebag, Vidal

    2015-01-01

    A 16-year-old patient with recurrent palpitations and documented left bundle branch block superior axis wide complex tachycardia underwent an electrophysiological study and ablation with a zero-fluoroscopy procedure. The electrophysiological study showed a decremental antegrade conducting atriofascicular pathway. Three-dimensional CARTO-guided mapping of the tricuspid annulus in sinus rhythm was performed, and a distinct signal corresponding to the accessory pathway potential of the atriofascicular pathway was found in the posterolateral region. By using an SR0 sheath and a 4-mm-tip catheter, radiofrequency application was delivered at this point on the annulus and successfully eliminated conduction through the accessory pathway. PMID:26550092

  11. Acquiring Multiview C-Arm Images to Assist Cardiac Ablation Procedures

    Fallavollita Pascal

    2010-01-01

    Full Text Available CARTO XP is an electroanatomical cardiac mapping system that provides 3D color-coded maps of the electrical activity of the heart; however it is expensive and it can only use a single costly magnetic catheter for each patient intervention. Our approach consists of integrating fluoroscopic and electrical data from the RF catheters into the same image so as to better guide RF ablation, shorten the duration of this procedure, increase its efficacy, and decrease hospital cost when compared to CARTO XP. We propose a method that relies on multi-view C-arm fluoroscopy image acquisition for (1 the 3D reconstruction of the anatomical structure of interest, (2 the robust temporal tracking of the tip-electrode of a mapping catheter between the diastolic and systolic phases and (3 the 2D/3D registration of color coded isochronal maps directly on the 2D fluoroscopy image that would help the clinician guide the ablation procedure much more effectively. The method has been tested on canine experimental data.

  12. Lego Mindstorm Maze Runner

    Drakonakis, Konstantinos; Mentzelopoulos, Panagiotis

    2014-01-01

    This project describes a method for solving mazes using a path finding algorithm, specifically DFS. Its input consists of the NXT lego robot along with a color sensor and a colored ball, the constructed maze and a text (.txt) file that describes the structure of the maze. Subsequently, the output of our program in order of execution is the identification of the provided colored ball, the calculation of the maze's solution (path) and the actual movement of the robot through the maze carrying t...

  13. Evaluation of exposure dose to patients undergoing catheter ablation procedures - a phantom study

    Seguchi, S. [Nagoya University, Graduate School of Medicine, Nagoya (Japan); Nagoya Daini Red Cross Hospital, Division of Radiology, Department of Medical Technology, Nagoya (Japan); Aoyama, T.; Koyama, S.; Kawaura, C. [Nagoya University, Graduate School of Medicine, Nagoya (Japan); Fujii, K. [Nagoya University, Graduate School of Medicine, Nagoya (Japan); National Institute of Radiological Sciences, Section of Radiological Protection, Chiba (Japan)

    2008-11-15

    The aim of this study was to evaluate entrance skin dose (ESD), organ dose and effective dose to patients undergoing catheter ablation for cardiac arrhythmias, based on the dosimetry in an anthropomorphic phantom. ESD values associated with mean fluoroscopy time and digital cine frames were in a range of 0.12-0.30 Gy in right anterior oblique (RAO) and 0.05-0.40 Gy in left anterior oblique (LAO) projection, the values which were less than a threshold dose of 2 Gy for the onset of skin injury. Organs that received high doses in ablation procedures were lung, followed by bone surface, esophagus, liver and red bone marrow. Doses for lung were 24.8-122.7 mGy, and effective doses were 7.9-34.8 mSv for mean fluoroscopy time of 23.4-92.3 min and digital cine frames of 263-511. Conversion coefficients of dose-area product (DAP) to ESD were 8.7 mGy/(Gy.cm{sup 2}) in RAO and 7.4 mGy/(Gy.cm{sup 2}) in LAO projection. The coefficients of DAP to the effective dose were 0.37 mSv/(Gy.cm{sup 2}) in RAO, and 0.41 mSv/(Gy.cm{sup 2}) in LAO projection. These coefficients enabled us to estimate patient exposure in real time by using monitored values of DAP. (orig.)

  14. Effective dose analysis of three-dimensional rotational angiography during catheter ablation procedures

    Wielandts, J.-Y.; Smans, K.; Ector, J.; De Buck, S.; Heidbüchel, H.; Bosmans, H.

    2010-02-01

    There is increasing use of three-dimensional rotational angiography (3DRA) during cardiac ablation procedures. As compared with 2D angiography, a large series of images are acquired, creating the potential for high radiation doses. The aim of the present study was to quantify patient-specific effective doses. In this study, we developed a computer model to accurately calculate organ doses and the effective dose incurred during 3DRA image acquisition. The computer model simulates the exposure geometry and uses the actual exposure parameters, including the variation in tube voltage and current that is realized through the automatic exposure control (AEC). We performed 3DRA dose calculations in 42 patients referred for ablation on the Siemens Axiom Artis DynaCT system (Erlangen, Germany). Organ doses and effective dose were calculated separately for all projections in the course of the C-arm rotation. The influence of patient body mass index (BMI), dose-area product (DAP), collimation and dose per frame (DPF) rate setting on the calculated doses was also analysed. The effective dose was found to be 5.5 ± 1.4 mSv according to ICRP 60 and 6.6 ± 1.8 mSv according to ICRP 103. Effective dose showed an inversely proportional relationship to BMI, while DAP was nearly BMI independent. No simple conversion coefficient between DAP and effective dose could be derived. DPF reduction did not result in a proportional effective dose decrease. These paradoxical findings were explained by the settings of the AEC and the limitations of the x-ray tube. Collimation reduced the effective dose by more than 20%. Three-dimensional rotational angiography is associated with a definite but acceptable radiation dose that can be calculated for all patients separately. Their BMI is a predictor of the effective dose. The dose reduction achieved with collimation suggests that its use is imperative during the 3DRA procedure.

  15. Effective dose analysis of three-dimensional rotational angiography during catheter ablation procedures

    Wielandts, J-Y; Ector, J; De Buck, S; Heidbuechel, H [Department of Electrophysiology-Cardiology, University Hospital Gasthuisberg, 49, Herestraat, 3000-Leuven (Belgium); Smans, K [Belgian Nuclear Research Centre (SCK-CEN), Radiation Protection, Dosimetry and Calibration, Boeretang, 2400-Mol (Belgium); Bosmans, H [Department of Radiology, University Hospital Gasthuisberg, 49, Herestraat, 3000-Leuven (Belgium)], E-mail: jean-yves.wielandts@uz.kuleuven.ac.be

    2010-02-07

    There is increasing use of three-dimensional rotational angiography (3DRA) during cardiac ablation procedures. As compared with 2D angiography, a large series of images are acquired, creating the potential for high radiation doses. The aim of the present study was to quantify patient-specific effective doses. In this study, we developed a computer model to accurately calculate organ doses and the effective dose incurred during 3DRA image acquisition. The computer model simulates the exposure geometry and uses the actual exposure parameters, including the variation in tube voltage and current that is realized through the automatic exposure control (AEC). We performed 3DRA dose calculations in 42 patients referred for ablation on the Siemens Axiom Artis DynaCT system (Erlangen, Germany). Organ doses and effective dose were calculated separately for all projections in the course of the C-arm rotation. The influence of patient body mass index (BMI), dose-area product (DAP), collimation and dose per frame (DPF) rate setting on the calculated doses was also analysed. The effective dose was found to be 5.5 {+-} 1.4 mSv according to ICRP 60 and 6.6 {+-} 1.8 mSv according to ICRP 103. Effective dose showed an inversely proportional relationship to BMI, while DAP was nearly BMI independent. No simple conversion coefficient between DAP and effective dose could be derived. DPF reduction did not result in a proportional effective dose decrease. These paradoxical findings were explained by the settings of the AEC and the limitations of the x-ray tube. Collimation reduced the effective dose by more than 20%. Three-dimensional rotational angiography is associated with a definite but acceptable radiation dose that can be calculated for all patients separately. Their BMI is a predictor of the effective dose. The dose reduction achieved with collimation suggests that its use is imperative during the 3DRA procedure.

  16. Electric Current Solves Mazes

    Ayrinhac, Simon

    2014-01-01

    We present in this work a demonstration of the maze-solving problem with electricity. Electric current flowing in a maze as a printed circuit produces Joule heating and the right way is instantaneously revealed with infrared thermal imaging. The basic properties of electric current can be discussed in this context, with this challenging question:…

  17. Rook Jumping Maze Design Considerations

    Neller, Todd W.; Fisher, Adrian; Choga, Munyaradzi T.; Lalvani, Samir M.; McCarty, Kyle D.

    We define the Rook Jumping Maze, provide historical perspective, and describe a generation method for such mazes. When applying stochastic local search algorithms to maze design, most creative effort concerns the definition of an objective function that rates maze quality. We define and discuss several maze features to consider in such a function definition. Finally, we share our preferred design choices, make design process observations, and note the applicability of these techniques to variations of the Rook Jumping Maze.

  18. Relationships between cardiac innervation/perfusion imbalance and ventricular arrhythmias: impact on invasive electrophysiological parameters and ablation procedures

    Gimelli, Alessia [Fondazione Toscana Gabriele Monasterio, Pisa (Italy); Menichetti, Francesca; Soldati, Ezio; Liga, Riccardo; Vannozzi, Andrea; Bongiorni, Maria Grazia [University Hospital of Pisa, Cardio-Thoracic and Vascular Department, Pisa (Italy); Marzullo, Paolo [Fondazione Toscana Gabriele Monasterio, Pisa (Italy); CNR, Institute of Clinical Physiology, Pisa (Italy)

    2016-12-15

    To assess the relationship between regional myocardial perfusion and sympathetic innervation parameters at myocardial scintigraphy and intra-cavitary electrophysiological data in patients with ventricular arrhythmias (VA) submitted to invasive electrophysiological study and ablation procedure. Sixteen subjects underwent invasive electrophysiological study with electroanatomical mapping (EAM) followed by trans-catheter ablations of VA. Before ablation all patients were studied with a combined evaluation of regional myocardial perfusion and sympathetic innervation by means of tomographic {sup 99m}Tc-tetrofosmin and {sup 123}I- metaiodobenzylguanidine cadmium-zinc-telluride (CZT) scintigraphies, respectively. Off-line spatial co-registration of CZT perfusion and innervation data with the three-dimensional EAM reconstruction was performed in every patient. CZT revealed the presence of myocardial scar in 55 (20 %) segments. Of the viable myocardial segments, 131 (60 %) presented a preserved adrenergic innervation, while 86 (40 %) showed a significantly depressed innervation (i.e. innervation/perfusion mismatch). On EAM, the invasively measured intra-cavitary voltage was significantly lower in scarred segments than in viable ones (1.7 ± 1.5 mV vs. 4.0 ± 2.2 mV, P < 0.001). Interestingly, among the viable segments, those showing an innervation/perfusion mismatch presented a significantly lower intra-cavitary voltage than those with preserved innervation (1.9 ± 2.5 mV vs. 4.7 ± 2.3 mV, P < 0.001). Intra-cardiac ablation was performed in 63 (23 %) segments. On multivariate analysis, after correction for scar burden, the segments showing an innervation/perfusion mismatch remained the most frequent ablation targets (OR 5.6, 95 % CI 1.5-20.8; P = 0.009). In patients with VA, intra-cavitary electrical abnormalities frequently originate at the level of viable myocardial segments with depressed sympathetic innervation that frequently represents the ultimate ablation target

  19. Impact of catheter ablation with remote magnetic navigation on procedural outcomes in patients with persistent and long-standing persistent atrial fibrillation

    Jin, Qi; Pehrson, Steen; Jacobsen, Peter Karl;

    2015-01-01

    BACKGROUND: The objectives of this study were to assess the procedural outcomes of persistent and long-standing persistent atrial fibrillation (PsAF and L-PsAF) ablation guided by remote magnetic navigation (RMN), and to detect factors predicting acute restoration of sinus rhythm (SR) by ablation...... with RMN. METHODS: A total of 313 patients (275 male, age 59 ± 9.5 years) with PsAF (187/313) or L-PsAF (126/313) undergoing ablation using RMN were included. Patients' disease history, pulmonary venous anatomy, left atrial (LA) volume, procedure time, mapping plus ablation time, radiofrequency (RF.......03). Stepwise regression analysis showed LA volume was the primary parameter affecting SR restoration (P = 0.01). The LA volume of patients without direct SR restoration by ablation was 24% greater than that of patients with SR restoration (P RMN is a safe...

  20. Radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia guided by magnetic navigation system: a prospective randomized comparison with conventional procedure

    ZHANG Yu-xiao; LU Cai-yi; XUE Qiao; LI Ke; YAN Wei; ZHOU Sheng-hua

    2012-01-01

    Background Atrioventricular nodal reentrant tachycardia (AVNRT) is one of the most common paroxysmal supraventricular tachyarrhythmias.The aim of the study was to prospectively compare the characteristics of radiofrequency catheter ablation of AVNRT guided by a magnetic navigation system with the conventional procedure.Methods Patients with AVNRT diagnosed by electrophysiological tests were randomized into two groups.In the conventional technique group (CMT),a common 4-mm-tip quadrapolar temperature-controlled ablation catheter was used. In the magnetic navigation system guidance group (MNS), a magnetic 4-mm-tip quadrapolar temperature-controlled ablation catheter was used.The following parameters were collected and compared between the two groups: ablation procedure time,patient fluoroscopy time,operator fluoroscopy time,energy delivery numbers,maximal energy per deployment,success rate,complication rate and operative cost.Results Forty patients were enrolled and randomized into CMT and MNS groups.The age,gender,tachycardia history and basic cardiovascular diseases of the two groups were comparable (P >0.05).All procedures were conducted successfully without complications.No tachycardia recurred during the follow-up period of (9.3±2.6) months.In the MNS group,the patient and operator fluoroscopy times ((11.5±4.3) min,(4.2±1.5) min),energy delivery numbers (3.2±0.9),and maximal energy per deployment ((16.9±3.4) W) were shorter or lower than those of the CMT group ((14.3±6.2) min,(13.6±3.5) min,6.3±2.1,(23.7±1.3) W,respectively) (P <0.05).But the operative cost for the MNS group was higher than that of the CMT group (P <0.01 ).Conclusion Magnetic navigation system guided radiofrequency catheter ablation of AVNRT has the advantages of shorter fluoroscopy time and lower energy delivery numbers and maximal energy per deployment compared to the present conventional ablation technique.

  1. Modified radial v/s biatrial maze for atrial fibrillation in rheumatic valvular heart surgery

    Sayed, Sajid A.; Katewa, Ashish; Srivastava, Vivek; Jana, Sujit; Patwardhan, Anil M.

    2014-01-01

    Background Atrial fibrillation (AF) is commonest sustained atrial arrhythmia producing high morbidity. Although Cox's Maze III procedure cures AF in majority, reduced atrial transport function (ATF) is a concern. Radial approach with ablation lines radial from sinus node towards atrioventricular annulii and parallel to atrial coronary arteries, has shown better ATF. Methods Single blind open randomized prospective study of 80 patients was undertaken in two groups (40 each) of modified Cox's maze III and modified radial approach, to evaluate conversion to normal sinus rhythm (NSR) and ATF. Patients undergoing surgery for rheumatic valvular heart disease with continuous AF were prospectively randomized. Ablation lines were created with radiofrequency (RF) bipolar coagulation with cryoablation for the isthmal lesions and coronary sinus. Results were compared at 6 months and ATF was evaluated by atrial filling fraction (AFF) and A/E ratio on echocardiography. Results The rate of conversion to NSR in both groups was statistically insignificant by Fisher's exact test (p > 0.05). ATF was better in modified radial approach compared to modified Cox's Maze III (A/E compared by unpaired t test:0.52 ± 0.08 v/s 0.36 ± 0.10; p < 0.05. AFF compared using Mann Whitney U test: median AFF for radial group was 23 v/s 20 for biatrial group; p < 0.05). Discussion In patients with AF undergoing rheumatic valvular surgery, radiofrequency radial approach is as effective as modified Cox's maze III for conversion to NSR with better atrial transport function. PMID:25443604

  2. Tratamento cirúrgico da fibrilação atrial: procedimento do "labirinto": experiência inicial Surgical treatment of atrial fibrillation with "maze" procedure: initial experience

    Adib D Jatene

    1992-06-01

    complicações infecciosas. Os pacientes restantes obtiveram alta hospitalar sem drogas antiarrítmicas. Em um período de um a dez meses (M = 5,4, os pacientes estão assintomáticos e o Holter mostra presença de ritmo atrial irregular permanente (com FC média de 70 a 80 bpm com condução AV preservada; o ecodoppler mostra presença de contração atrial eficiente. Não houve recorrências de FA e nenhum dos pacientes. Em conclusão, podemos admitir que, a curto prazo, a técnica do "labirinto" na FA em reumáticos restaurou a contração atrial organizada e controlou a FC. Assim, pode contribuir para redução de fenômenos trombo-embólicos. Maior número de pacientes deve ser observado durante tempo prolongado para avaliação da eficácia do procedimento.The "maze" procedure for surgical treatment of chronic atrial fibrillation (AF described by Cox was performed in 9 patients from July 91 to May 92; 7 were female and the ages range from 37 to 63y (51,4y. Eight patients had surgical rheumatic valve disfunction (mitral stenosis in 6; mitral double disfunction in 2 being 1 with associated tricuspid regurgitation and 1 had recurrent paroxicistic AF with no valve disfunction. Surgical treatment was performed following the technique described by Cox and the surgery was completed with 6 mitral comissurotomies and 2 mitral valve replacements. Three patients had left atrial thrombosis. There were no immediate deaths and 1 patient died in the 45th day with infeccious complications. The first patient required reoperation for bleeding review. Second and 3rd patients presented transitory atrial tachycardia in 3rd and 5th day, controlled with intravenous amiodarone. No other complications were observed. In a mean follow up period of 5,4m (1 to 10 m, all patients were in regular atrial rhythm without antiarrhythmic drugs. Effective atrial contraction was demonstrated by ECHO in all patients and no one returned to AF. In conclusion, this initial follow up showed good results in

  3. Reinforce the study of treatment of atrial fibrillation by catheter ablation

    HUANG Cong-xin

    2005-01-01

    @@ In the past decade, there is a great progress in the treatment of atrial fibrillation (AF) by transcatheter ablation. The catheter-based procedures have developed from Maze-like linear lesion, focal lesion to segmental electrical isolation of pulmonary veins and circumferential ablation under guidance of anatomical mapping, ablation energy developed from radiofrequency to multiple energy such as radiofrequency, ultrasound and cryoablation; and success rate has risen to 90% from around 30% in the past.1 Catheter ablation has been widely accepted as a treatment of AF and tends to substitute pharmacological therapy and become first-line treatment gradually. It must point out that, however, catheter ablation of AF is not perfect and there are many issues desiderating resolution.

  4. Long-term results of single-procedure catheter ablation for atrial fibrillationin pre-and post-menopausal women

    Tao LIN; Chang-Sheng MA; Jian-Zeng DONG; Xing DU; Rong BAI; Ying-Wei CHEN; Rong-Hui YU; De-Yong LONG; Ri-Bo TANG; Cai-Hua SANG; Song-Nan LI

    2014-01-01

    Objectives To address whether menopause affects outcome of catheter ablation (CA) for atrial fibrillation (AF) by comparing the safety and long-term outcome of a single-procedure in pre-and post-menopausal women. Methods A total of 743 female patients who underwent a single CA procedure of drug-refractory AF were retrospectively analyzed. The differences in clinical presentation and outcomes of CA for AF between the pre-menopausal women (PreM group, 94 patients, 12.7%) and the post-menopausal women (PostM group, 649 patients, 87.3%) were assessed. Results The patients in the PreM group were younger (P<0.001) and less likely to have hypertension (P<0.001) and diabetes (P=0.005) than those in the PostM group. The two groups were similar with regards to the proportion of concomitant mitral valve regurgitation coronary artery disease, left atrium dimensions, and left ventricular ejection fraction. The overall rate of complica-tions related to AF ablation was similar in both groups (P=0.385). After 43 (16-108) months of follow-up, the success rate of ablation was 54.3%in the PreM group and 54.2%in the PostM group (P=0.842). The overall freedom from atrial tachyarrhythmia recurrence was simi-lar in both groups. Menopause was not found to be an independent predictive factor of the recurrence of atrial tachyarrhythmia. Conclusions The long-term outcomes of single-procedure CA for AF are similar in pre-and post-menopausal women. Results indicated that CA of AF appears to be as safe and effective in pre-menopausal women as in post-menopausal women.

  5. 2D/3D registration using only single-view fluoroscopy to guide cardiac ablation procedures: a feasibility study

    Fallavollita, Pascal

    2010-02-01

    The CARTO XP is an electroanatomical cardiac mapping system that provides 3D color-coded maps of the electrical activity of the heart, however it is expensive and it can only use a single costly magnetic catheter for each patient intervention. Aim: To develop an affordable fluoroscopic navigation system that could shorten the duration of RF ablation procedures and increase its efficacy. Methodology: A 4-step filtering technique was implemented in order to project the tip electrode of an ablation catheter visible in single-view C-arm images in order to calculate its width. The width is directly proportional to the depth of the catheter. Results: For phantom experimentation, when displacing a 7- French catheter at 1cm intervals away from an X-ray source, the recovered depth using a single image was 2.05 +/- 1.47 mm, whereas depth errors improved to 1.55 +/- 1.30 mm when using an 8-French catheter. In clinic experimentation, twenty posterior and left lateral images of a catheter inside the left ventricle of a mongrel dog were acquired. The standard error of estimate for the recovered depth of the tip-electrode of the mapping catheter was 13.1 mm and 10.1 mm respectively for the posterior and lateral views. Conclusions: A filtering implementation using single-view C-arm images showed that it was possible to recover depth in phantom study and proved adequate in clinical experimentation based on isochronal map fusion results.

  6. Cone-Beam Computed Tomography (CBCT) Versus CT in Lung Ablation Procedure: Which is Faster?

    Cazzato, Roberto Luigi, E-mail: r.cazzato@unicampus.it; Battistuzzi, Jean-Benoit, E-mail: j.battistuzzi@bordeaux.unicancer.fr; Catena, Vittorio, E-mail: vittoriocatena@gmail.com [Institut Bergonié, Department of Radiology (France); Grasso, Rosario Francesco, E-mail: r.grasso@unicampus.it; Zobel, Bruno Beomonte, E-mail: b.zobel@unicampus.it [Università Campus Bio-Medico di Roma, Department of Radiology and Diagnostic Imaging (Italy); Schena, Emiliano, E-mail: e.schena@unicampus.it [Università Campus Bio-Medico di Roma, Unit of Measurements and Biomedical Instrumentations, Biomedical Engineering Laboratory (Italy); Buy, Xavier, E-mail: x.buy@bordeaux.unicancer.fr; Palussiere, Jean, E-mail: j.palussiere@bordeaux.unicancer.fr [Institut Bergonié, Department of Radiology (France)

    2015-10-15

    AimTo compare cone-beam CT (CBCT) versus computed tomography (CT) guidance in terms of time needed to target and place the radiofrequency ablation (RFA) electrode on lung tumours.Materials and MethodsPatients at our institution who received CBCT- or CT-guided RFA for primary or metastatic lung tumours were retrospectively included. Time required to target and place the RFA electrode within the lesion was registered and compared across the two groups. Lesions were stratified into three groups according to their size (<10, 10–20, >20 mm). Occurrences of electrode repositioning, repositioning time, RFA complications, and local recurrence after RFA were also reported.ResultsForty tumours (22 under CT, 18 under CBCT guidance) were treated in 27 patients (19 male, 8 female, median age 67.25 ± 9.13 years). Thirty RFA sessions (16 under CBCT and 14 under CT guidance) were performed. Multivariable linear regression analysis showed that CBCT was faster than CT to target and place the electrode within the tumour independently from its size (β = −9.45, t = −3.09, p = 0.004). Electrode repositioning was required in 10/22 (45.4 %) tumours under CT guidance and 5/18 (27.8 %) tumours under CBCT guidance. Pneumothoraces occurred in 6/14 (42.8 %) sessions under CT guidance and in 6/16 (37.5 %) sessions under CBCT guidance. Two recurrences were noted for tumours receiving CBCT-guided RFA (2/17, 11.7 %) and three after CT-guided RFA (3/19, 15.8 %).ConclusionCBCT with live 3D needle guidance is a useful technique for percutaneous lung ablation. Despite lesion size, CBCT allows faster lung RFA than CT.

  7. Predictive value of pre-procedural autoantibodies against M2-muscarinic acetylcholine receptor for recurrence of atrial fibrillation one year after radiofrequency catheter ablation

    Zou Changhong

    2013-01-01

    Full Text Available Abstract Background Increasing evidences have suggested that autoantibodies against muscarinic-2 acetylcholine receptor (anti-M2-R may play an important role in the development of atrial fibrillation (AF. Predictive value of pre-procedural anti-M2-R for the recurrence of AF after radiofrequency catheter ablation is still unclear. Methods Totally 76 AF patients with preserved left ventricular systolic function were prospectively enrolled and subjected to ablation after the detection of serum anti-M2-R by enzyme linked immunosorbent assay. These patients were given follow-up examination for one year after ablation. Risk estimation for the recurrence of AF was performed using the univariate and multivariate logistic regression. Results In AF group, serum anti-M2-R was significantly higher than that in the control group in terms of frequency (40.8% versus 11.7%; p p p = 0.009 and titer (1:132 versus 1:94; p = 0.012 for autoantibodies. During one-year follow-up examination after ablation, the recurrence of AF was observed in 25 (32.9% patients. Multivariate analysis showed that pre-procedural serum anti-M2-R was an independent predictor for the recurrence of AF at the time point of 12 months after ablation (odds ratio: 4.701; 95% confidence interval: 1.590-13.894; p = 0.005. Conclusions In AF patients, the frequency and titer of serum anti-M2-R were significantly higher than those in the control group with sinus rhythm. Pre-procedural serum anti-M2-R was an independent predictor for the recurrence of AF one year after radiofrequency catheter ablation.

  8. Spatial reference- (not working- or procedural-) memory performance of aged rats in the water maze predicts the magnitude of sulpiride-induced facilitation of acetylcholine release by striatal slices.

    Cassel, Jean-Christophe; Lazaris, Anelise; Birthelmer, Anja; Jackisch, Rolf

    2007-08-01

    Cluster analysis of water-maze reference-memory performance distinguished subpopulations of young adult (3-5 months), aged (25-27 months) unimpaired (AU) and aged impaired (AI) rats. Working-memory performances of AU and AI rats were close to normal (though young and aged rats differed in exploration strategies). All aged rats showed impaired procedural-memory. Electrically evoked release of tritium was assessed in striatal slices (preloaded with [(3)H]choline) in the presence of oxotremorine, physostigmine, atropine+physostigmine, quinpirole, nomifensine or sulpiride. Aged rats exhibited reduced accumulation of [(3)H]choline (-30%) and weaker transmitter release. Drug effects (highest concentration) were reductions of release by 44% (oxotremorine), 72% (physostigmine), 84% (quinpirole) and 65% (nomifensine) regardless of age. Sulpiride and atropine+physostigmine facilitated the release more efficiently in young rats versus aged rats. The sulpiride-induced facilitation was weaker in AI rats versus AU rats; it significantly correlated with reference-memory performance. The results confirm age-related alterations of cholinergic and dopaminergic striatal functions, and point to the possibility that alterations in the D(2)-mediated dopaminergic regulation of these functions contribute to age-related reference-memory deficits.

  9. Limited posterior left atrial linear radiofrequency ablation for patients with chronic atrial fibrillation undergoing rheumatic valvular heart surgery

    王均志; 杜日映; 丁会霞; 柏本健; 王刚; 崔国方; 钟志欢

    2004-01-01

    @@ Since 1996, we have begun to successfully treat atrial fibrillation (AF) with the maze procedure, replacing surgical incisions with radiofrequency (RF) ablation.1,2 Recent data show that the posterior wall of the left atrium seems to be a critical area for the occurrence and the maintenance of AF in patients with valvular heart disease. The objective of this study was to evaluate whether limited surgical RF ablation of the posterior region of the left atrium is safe and effective in curing chronic AF in patients also suffering from valvular heart disease.

  10. Quantitative modeling of the accuracy in registering preoperative patient-specific anatomic models into left atrial cardiac ablation procedures

    Rettmann, Maryam E., E-mail: rettmann.maryam@mayo.edu; Holmes, David R.; Camp, Jon J.; Cameron, Bruce M.; Robb, Richard A. [Biomedical Imaging Resource, Mayo Clinic College of Medicine, Rochester, Minnesota 55905 (United States); Kwartowitz, David M. [Department of Bioengineering, Clemson University, Clemson, South Carolina 29634 (United States); Gunawan, Mia [Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington D.C. 20057 (United States); Johnson, Susan B.; Packer, Douglas L. [Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota 55905 (United States); Dalegrave, Charles [Clinical Cardiac Electrophysiology, Cardiology Division Hospital Sao Paulo, Federal University of Sao Paulo, 04024-002 Brazil (Brazil); Kolasa, Mark W. [David Grant Medical Center, Fairfield, California 94535 (United States)

    2014-02-15

    Purpose: In cardiac ablation therapy, accurate anatomic guidance is necessary to create effective tissue lesions for elimination of left atrial fibrillation. While fluoroscopy, ultrasound, and electroanatomic maps are important guidance tools, they lack information regarding detailed patient anatomy which can be obtained from high resolution imaging techniques. For this reason, there has been significant effort in incorporating detailed, patient-specific models generated from preoperative imaging datasets into the procedure. Both clinical and animal studies have investigated registration and targeting accuracy when using preoperative models; however, the effect of various error sources on registration accuracy has not been quantitatively evaluated. Methods: Data from phantom, canine, and patient studies are used to model and evaluate registration accuracy. In the phantom studies, data are collected using a magnetically tracked catheter on a static phantom model. Monte Carlo simulation studies were run to evaluate both baseline errors as well as the effect of different sources of error that would be present in a dynamicin vivo setting. Error is simulated by varying the variance parameters on the landmark fiducial, physical target, and surface point locations in the phantom simulation studies. In vivo validation studies were undertaken in six canines in which metal clips were placed in the left atrium to serve as ground truth points. A small clinical evaluation was completed in three patients. Landmark-based and combined landmark and surface-based registration algorithms were evaluated in all studies. In the phantom and canine studies, both target registration error and point-to-surface error are used to assess accuracy. In the patient studies, no ground truth is available and registration accuracy is quantified using point-to-surface error only. Results: The phantom simulation studies demonstrated that combined landmark and surface-based registration improved

  11. The procedure outcome of laparoscopic resection for ‘small’ hepatocellular carcinoma is comparable to vlaparoscopic radiofrequency ablation

    Casaccia, Marco; Santori, Gregorio; Bottino, Giuliano; Diviacco, Pietro; Negri, Antonella De; Moraglia, Eva; Adorno, Enzo

    2015-01-01

    BACKGROUND: The aim of this study was to compare the effectiveness of laparoscopic liver resection (LLR) and laparoscopic radiofrequency ablation (LRFA) in the treatment of small nodular hepatocellular carcinoma (HCC). PATIENTS AND METHODS: We enrolled 50 cirrhotic patients with similar baseline characteristics that underwent LLR (n = 26) or LRFA (n = 24), in both cases with intraoperative ultrasonography. Operative and peri-operative data were retrospectively evaluated. RESULTS: LLR included anatomic resection in eight cases and non-anatomic resection in 18. In LRFA patients, a thermoablation of 62 nodules was achieved. Between LLR and LRFA groups, a significant difference was found both for median diameters of treated HCC nodules (30 vs. 17.1 mm; P < 0.001) and the number of treated nodules/patient (1.29 ± 0.62 vs. 2.65 ± 1.55; P < 0.001). A conversion to laparotomy occurred in two LLR patient (7.7%) for bleeding. No deaths occurred in both groups. Morbidity rates were 26.9% in the LLR group versus 16.6% in the LRFA group (P = 0.501). Hospital stay in the LLR and LRFA group was 8.30 ± 6.52 and 6.52 ± 2.69 days, respectively (P = 0.022). The surgical margin was free of tumour cells in all LLR patients, with a margin <5 mm in only one case. In the LRFA group, a complete response was achieved in 90.3% of thermoablated HCC nodules at the 1-month post-treatment computed tomography evaluation. CONCLUSIONS: LLR for small peripheral HCC in patients with chronic liver disease represents a valid alternative to LRFA in terms of patient toleration, surgical outcome of the procedure, and short-term morbidity. PMID:26622111

  12. Second Language Learning with the Story Maze Task: Examining the Training Effect of Weaving through Stories

    Enkin, Elizabeth

    2016-01-01

    The maze task is a psycholinguistic experimental procedure that measures real-time incremental sentence processing. The task has recently been tested as a language learning tool with promising results. Therefore, the present study examines the merits of a contextualized version of this task: the story maze. The findings are consistent with…

  13. Implementation of Endovenous Laser Ablation for Varicose Veins in a Large Community Hospital : The First 400 Procedures

    van den Bremer, J.; Joosten, P. Ph. A. Hedeman; Hamming, J. F.; Moll, F. L.

    2009-01-01

    Endovenous Laser ablation (ELA) has become a standard treatment of the incompetent great saphenous vein (GSV). Our prospective audit examines the implementation of this new method in a large community hospital with special attention to obstacles, technical results, pain scores, failures and our lear

  14. Percutaneous radiofrequency ablation: relationship between different probe types and procedure time on length and extent of osteonecrosis in dog long bones

    Martel, J.; Bueno, A. [Fundacion Hospital Alcorcon, Departamento de Diagnostico por Imagen, Alcorcon, Madrid (Spain); Dominguez, M.P. [Fundacion Hospital Alcorcon, Departamento de Patologia, Alcorcon, Madrid (Spain); Llorens, P.; Quiros, J.; Delgado, C. [Universidad Complutense, Facultad de Veterinaria, Madrid (Spain)

    2008-02-15

    We have been using radiofrequency ablation for the percutaneous treatment of osteoid osteoma since 2001. Frequently, lesions are located near the joint surface, involve the vertebral body or are close to major nerves. We seek to determine whether radiofrequency ablation (RFA) can be used safely in these cases. A total of 65 lesions were induced in 4 dogs. Each dog underwent RFA on the diaphysis of long bones, as well as femoral and humeral heads. Four different sessions were carried out by using 1- and 2-cm probes with or without a cool-tip system and by varying the timing of the procedure. Plain film, CT, and MRI were obtained. All bone samples were examined histologically. The dogs' activity after the procedure was normal. No pathologic fractures occurred despite unrestricted activity of the animals. Cortical bone was always respected; therefore, articular cartilage has not been damaged. Radiological findings were characteristic. There were no significant differences in lesion size, probe type, and the duration of the procedure. The mean lesion diameter perpendicular to the electrode was 18.5 mm. Our study confirms the insulative effect of cortical bone. RFA can be safely performed close to the joint surface without damaging the cartilage. (orig.)

  15. Magnetic resonance angiography virtual endoscopy in the assessment of pulmonary veins before radiofrequency ablation procedures for atrial fibrillation

    Cirillo, S.; Tosetti, Irene; Giuseppe, M.De; Longo, M.; Regge, D. [Institute for Cancer Research and Treatment (IRCC), Unit of Radiology, Candiolo (Torino) (Italy); Bonamini, R. [University of Torino, Department of Cardiology, Torino (Italy); Gaita, F.; Bianchi, F.; Vivalda, L. [Ospedale Mauriziano Umberto I, Department of Cardiology, Torino (Italy)

    2004-11-01

    Magnetic resonance angiography (MRA) is a safe and non-invasive imaging method that can readily depict the pulmonary veins (PV), whose imaging has acquired momentum with the advent of new techniques for radiofrequency ablation of atrial fibrillation (AF). We evaluated whether virtual endoscopy from 3D MRA images (MRA-VE) is feasible in studying the morphology of PV. Fifty patients with AF underwent pre-ablative MRA (1.5 T). Images were acquired with axial T-2 weighted and 3D-SPGR sequences after intravenous administration of Gd-DTPA and automatic triggering. Postprocessing was performed by an experienced radiologist with maximum intensity projection (MIP) and virtual endoscopy software (Navigator, GEMS). The venoatrial junction was visualized with MRA-VE in 49 of 50 patients (98.0%). Twenty-seven patients (55.1%) had two ostia on both sides, 13 patients (26.5%) had two ostia on the right and a single common ostium on the left, 5 patients (10.2%) had accessory PV and 4 patients (8.2%) had both an accessory right PV and a single common ostium on the left. Flythrough navigation showed the number and spatial disposition of second-order PV branches in 48 out of 49 patients (98.0%). MRA-VE is an excellent tool for at-a-glance visualization of ostia morphology, navigation of second-generation PV branches and easy endoluminal assessment of left atrial structures in pre-ablative imaging. (orig.)

  16. Estimating Effective Dose from Phantom Dose Measurements in Atrial Fibrillation Ablation Procedures and Comparison of MOSFET and TLD Detectors in a Small Animal Dosimetry Setting

    Anderson-Evans, Colin David

    Two different studies will be presented in this work. The first involves the calculation of effective dose from a phantom study which simulates an atrial fibrillation (AF) ablation procedure. The second involves the validation of metal-oxide semiconducting field effect transistors (MOSFET) for small animal dosimetry applications as well as improved characterization of the animal irradiators on Duke University's campus. Atrial Fibrillation is an ever increasing health risk in the United States. The most common type of cardiac arrhythmia, AF is associated with increased mortality and ischemic cerebrovascular events. Managing AF can include, among other treatments, an interventional procedure called catheter ablation. The procedure involves the use of biplane fluoroscopy during which a patient can be exposed to radiation for as much as two hours or more. The deleterious effects of radiation become a concern when dealing with long fluoroscopy times, and because the AF ablation procedure is elective, it makes relating the risks of radiation ever more essential. This study hopes to quantify the risk through the derivation of dose conversion coefficients (DCCs) from the dose-area product (DAP) with the intent that DCCs can be used to provide estimates of effective dose (ED) for typical AF ablation procedures. A bi-plane fluoroscopic and angiographic system was used for the simulated AF ablation procedures. For acquisition of organ dose measurements, 20 diagnostic MOSFET detectors were placed at selected organs in a male anthropomorphic phantom, and these detectors were attached to 4 bias supplies to obtain organ dose readings. The DAP was recorded from the system console and independently validated with an ionization chamber and radiochromic film. Bi-plane fluoroscopy was performed on the phantom for 10 minutes to acquire the dose rate for each organ, and the average clinical procedure time was multiplied by each organ dose rate to obtain individual organ doses. The

  17. Radiofrequency ablation in dermatology

    Sachdeva Silonie

    2007-01-01

    Full Text Available Radiofreqeuency ablation is a versatile dermatosurgical procedure used for surgical management of skin lesions by using various forms of alternating current at an ultra high frequency. The major modalities in radiofrequency are electrosection, electrocoagulation, electrodessication and fulguration. The use of radiofrequency ablation in dermatosurgical practice has gained importance in recent years as it can be used to treat most of the skin lesions with ease in less time with clean surgical field due to adequate hemostasis and with minimal side effects and complications. This article focuses on the major tissue effects and factors influencing radiofrequency ablation and its application for various dermatological conditions.

  18. Sacro-Iliac Joint Sensory Block and Radiofrequency Ablation: Assessment of Bony Landmarks Relevant for Image-Guided Procedures

    Roberts, Shannon L.; Burnham, Robert S.; Loh, Eldon; Agur, Anne M.

    2016-01-01

    Image-guided sensory block and radiofrequency ablation of the nerves innervating the sacro-iliac joint require readily identifiable bony landmarks for accurate needle/electrode placement. Understanding the relative locations of the transverse sacral tubercles along the lateral sacral crest is important for ultrasound guidance, as they demarcate the position of the posterior sacral network (S1–S3 ± L5/S4) innervating the posterior sacro-iliac joint. No studies were found that investigated the spatial relationships of these bony landmarks. The purpose of this study was to visualize and quantify the interrelationships of the transverse sacral tubercles and posterior sacral foramina to inform image-guided block and radiofrequency ablation of the sacro-iliac joint. The posterior and lateral surfaces of 30 dry sacra (15 M/15 F) were digitized and modeled in 3D and the distances between bony landmarks quantified. The relationships of bony landmarks (S1–S4) were not uniform. The mean intertubercular and interforaminal distances decreased from S1 to S4, whereas the distance from the lateral margin of the posterior sacral foramina to the transverse sacral tubercles increased from S1 to S3. The mean intertubercular distance from S1 to S3 was significantly (p < 0.05) larger in males. The interrelationships of the sacral bony landmarks should be taken into consideration when estimating the site and length of an image-guided strip lesion targeting the posterior sacral network. PMID:27747222

  19. Repeat procedure using radiofrequency energy for recurrence of atrial fibrillation after initial cryoballoon ablation: a 2-year follow-up

    Conte, G.; Chierchia, G.B.; Sieira, J.; Levinstein, M.; Casado-Arroyo, R.; Asmundis, C. de; Sarkozy, A.; Rodriguez-Manero, M.; Giovanni, G.; Baltogiannis, G.; Wauters, K.; Brugada, P.

    2013-01-01

    AIMS: The ideal energy source needed to perform 're-isolation' of the pulmonary veins (PVs) during a repeat procedure for recurrence of paroxysmal atrial fibrillation (AF) has not been established yet. In this study we analysed the outcome of repeat procedure using radiofrequency (RF) energy after i

  20. Analytical procedure for characterization of medieval wall-paintings by X-ray fluorescence spectrometry, laser ablation inductively coupled plasma mass spectrometry and Raman spectroscopy

    Syta, Olga; Rozum, Karol; Choińska, Marta; Zielińska, Dobrochna; Żukowska, Grażyna Zofia; Kijowska, Agnieszka; Wagner, Barbara

    2014-11-01

    Analytical procedure for the comprehensive chemical characterization of samples from medieval Nubian wall-paintings by means of portable X-ray fluorescence (pXRF), laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) and Raman spectroscopy (RS) was proposed in this work. The procedure was used for elemental and molecular investigations of samples from archeological excavations in Nubia (modern southern Egypt and northern Sudan). Numerous remains of churches with painted decorations dated back to the 7th-14th century were excavated in the region of medieval kingdoms of Nubia but many aspects of this art and its technology are still unknown. Samples from the selected archeological sites (Faras, Old Dongola and Banganarti) were analyzed in the form of transfers (n = 26), small fragments collected during the excavations (n = 35) and cross sections (n = 15). XRF was used to collect data about elemental composition, LA-ICPMS allowed mapping of selected elements, while RS was used to get the molecular information about the samples. The preliminary results indicated the usefulness of the proposed analytical procedure for distinguishing the substances, from both the surface and sub-surface domains of the wall-paintings. The possibility to identify raw materials from the wall-paintings will be used in the further systematic, archeometric studies devoted to the detailed comparison of various historic Nubian centers.

  1. Evaluation of the NovaSure endometrial ablation procedure in women with uterine cavity length over 10 cm.

    Thiel, John A; Briggs, M Martha; Pohlman, Scott; Rattray, Darrien

    2014-06-01

    Objectif : Comparer, chez des femmes ayant subi une ablation de l’endomètre au moyen de la technique NovaSure et présentant une longueur utérine déterminée par hystérométrie de plus de 10 cm ou de 10 cm ou moins, les événements indésirables associés à l’intervention, l’état des saignements menstruels à la suite de l’intervention et la nécessité de procéder à une nouvelle intervention chirurgicale. Méthodes : Nous avons mené une étude de cohorte rétrospective qui portait sur 188 femmes ayant fréquenté une pratique gynécologique communautaire au Canada. Quatre-vingt-sept de ces femmes présentaient une longueur utérine déterminée par hystérométrie de plus de 10 cm, tandis que les 101 autres présentaient une longueur utérine déterminée par hystérométrie de 10 cm ou moins. Les événements indésirables associés à l’intervention, l’état des saignements menstruels à la suite de l’intervention et la nécessité de procéder à une nouvelle intervention chirurgicale sont les paramètres qui ont été comparés chez ces deux groupes de femmes. Résultats : Les longueurs utérines moyennes déterminées par hystérométrie ont été de 11,0 ± 0,6 cm et de 8,9 ± 0,8 cm au sein des groupes « > 10 cm » et « ≤ 10 cm », respectivement. Aucune différence n’a été constatée entre les groupes en matière de caractéristiques démographiques ou d’antécédents gynécologiques, exception faite d’un IMC accru au sein du groupe « > 10 cm » et d’une prévalence accrue de dysménorrhée au sein du groupe « ≤ 10 cm ». De façon globale, 44,1 % de toutes les participantes avaient connu l’échec de l’hormonothérapie et 20,7 % avaient connu l’échec d’un traitement non hormonal avant la tenue de l’ablation. Les participantes composant les autres 35,2 % avaient refusé d’avoir recours à un traitement de rechange et décidé de subir directement une ablation de l

  2. A single apheresis procedure in the donor may be enough to complete an allograft using the “Mexican Method” of non-ablative allografting

    Ruiz-Delgado, Guillermo J.; Gutiérrez-Riveroll, Karla I.; Gutiérrez-Aguirre, César H.; Gómez-Almaguer, David; Eyzaguirre-Zapata, Renee; Priesca-Marin, Manuel; González-Carrillo, Martha L.; Ruiz-Argüelles, Guillermo J.

    2009-01-01

    Background Since 1999, in Mexico we have been using a regimen to conduct allografts that involves non-myeloablative conditioning and peripheral blood stem cells (PBSC) and have introduced some changes with the main goal of decreasing the cost of the procedure. Materials and methods We analysed the salient apheresis features of a group of 175 allogeneic peripheral blood stem cell transplants conducted in two institutions in a 7-year period. The grafts were conducted using the “Mexican” non-myelo ablative conditioning regimen employing oral busulphan, i.v. cyclophosphamide and i.v. fludarabine. In all instances, the apheresis machine employed was the Baxter CS3000 Plus and donors were mobilised with filgrastim. The apheresis procedures were performed on days 0, +1 and +2, the end-point of collection being 5,000 mL of blood/m2 in each procedure. Three apheresis sessions were planned but the number was adjusted according to the cell yield. Results The final number of allografted CD34 cells ranged between 0.5 and 25.4 × 106/Kg of the recipient’s body weight (median, 5.2 × 106/Kg). One to three apheresis procedures were needed to obtain a product containing more than 0.5 × 106 CD34 cells/Kg of the recipient, the median being two procedures; in 72 cases (41%) a single apheresis procedure was sufficient to obtain the target number of CD34 cells. The volumes of apheresis ranged between 50 and 600 mL (median, 400 mL). Conclusions Since the median cost of each apheresis procedure is 900 USD, the fact that two apheresis procedures was spared in 72 cases and one apheresis was spared in another 65 cases, led to a total saving of approximately 188,100 USD. It can be concluded that, in many cases, allogeneic transplants can be completed with a single apheresis session and that there are considerable financial benefits from this practice. PMID:19503634

  3. Analytical procedure for characterization of medieval wall-paintings by X-ray fluorescence spectrometry, laser ablation inductively coupled plasma mass spectrometry and Raman spectroscopy

    Syta, Olga; Rozum, Karol; Choińska, Marta [Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland); Zielińska, Dobrochna [Institute of Archaeology, University of Warsaw, Krakowskie Przedmieście 26/28, 00-927 Warsaw (Poland); Żukowska, Grażyna Zofia [Chemical Faculty, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland); Kijowska, Agnieszka [National Museum in Warsaw, Aleje Jerozolimskie 3, 00-495 Warsaw (Poland); Wagner, Barbara, E-mail: barbog@chem.uw.edu.pl [Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland)

    2014-11-01

    Analytical procedure for the comprehensive chemical characterization of samples from medieval Nubian wall-paintings by means of portable X-ray fluorescence (pXRF), laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) and Raman spectroscopy (RS) was proposed in this work. The procedure was used for elemental and molecular investigations of samples from archeological excavations in Nubia (modern southern Egypt and northern Sudan). Numerous remains of churches with painted decorations dated back to the 7th–14th century were excavated in the region of medieval kingdoms of Nubia but many aspects of this art and its technology are still unknown. Samples from the selected archeological sites (Faras, Old Dongola and Banganarti) were analyzed in the form of transfers (n = 26), small fragments collected during the excavations (n = 35) and cross sections (n = 15). XRF was used to collect data about elemental composition, LA-ICPMS allowed mapping of selected elements, while RS was used to get the molecular information about the samples. The preliminary results indicated the usefulness of the proposed analytical procedure for distinguishing the substances, from both the surface and sub-surface domains of the wall-paintings. The possibility to identify raw materials from the wall-paintings will be used in the further systematic, archeometric studies devoted to the detailed comparison of various historic Nubian centers. - Highlights: • The analytical procedure for examination of unique wall paintings was proposed. • Identification of pigments and supporting layers of wall-paintings was obtained. • Heterogeneous samples were mapped with the use of LA-ICPMS. • Anatase in the sub-surface regions of samples was detected by Raman spectroscopy.

  4. Curative effects of two new endometrial ablation procedures using radiofrequency thermocoagulation for the treatment of severe abnormal uterine bleeding.

    Yin, Geping; Li, Juan; Zhu, Tongyu; Chen, Ming

    2013-07-01

    Severe Abnormal Uterine Bleeding (SAUB) is a common gynecological disorder. The clinical characteristics include disordered menstrual cycle and massive bleeding that can cause anemia or secondary infection. Current treatment mainly relies on drug therapy or surgical removal of the uterus, each having its significant disadvantages. How to preserve the uterus, reduce the pain from surgery, and achieve better treatment effects have been well known but remaining as unresolved issues. This study aims at evaluating two types of radiofrequency (RF) thermocoagulation procedures for the treatment of SAUB: the RF-A procedure group included 25 SAUB patients ≥45 years of age treated for amenorrhea; the RF-B procedure group included 51 patients at bleeding. Post-treatment ratings of menstrual satisfaction and pre-/post-treatment menstrual scores-pictorial blood loss assessment chart (PBAC)-and hemoglobin levels were collected; and the mean length of follow-up was 72 months. Also, 38 SAUB patients treated with standard drug regimens served as a control group. The results of the study showed that following RF treatment, the average long-term patient menstrual satisfaction was greater than 92 %. In both the RF groups, PBAC scores and hemoglobin levels were significantly improved from baseline (p < .05). Compared with the control group, PBAC scores and hemoglobin levels were also significantly better for the RF groups at 6-24-month post-operation. Patients experienced no hysterectomy in association with the RF procedures. In conclusion, this pilot study suggests that the novel RF procedures are both safe and effective in treating patients with SAUB. Further investigation is necessary to evaluate their application in broader clinical indication.

  5. [Glass maze in women's leadership].

    Barberá Heredia, Ester; Ramos López, Amparo; Candela Agulló, Carlos

    2011-04-01

    Psychological gender discrimination explanations have changed over the past thirty years, becoming more complex in order to obtain a better understanding of the social reality. At the present moment, one of the most interesting research areas is the one referring to the 'glass maze' phenomenon in women's management careers. The main purpose of this work is to reveal the theoretical evolution in an attempt to explain the leadership study from a gender perspective. The consecutive hypotheses, starting with the labour sexual division idea, are becoming more interactive in order to understand the current labour-social situation. Social psychology has underlined the role of beliefs, observed via gender stereotyped roles, prejudiced attitudes against women, sexist and neo-sexist ideology, or masculine, feminine and androgynous identity development. New psychological interpretations insist on the variability of the gender concept, where gender is sometimes observed through men and women's behaviours, and other times through those behaviour expectations. But gender is mainly observed though the power relations between men and women during social interactions in labour organizations.

  6. Glow discharge based device for solving mazes

    Dubinov, Alexander E., E-mail: dubinov-ae@yandex.ru; Mironenko, Maxim S.; Selemir, Victor D. [Russian Federal Nuclear Center − All-Russian Scientific and Research Institute of Experimental Physics (RFNC-VNIIEF), Sarov, Nizhni Novgorod region 607188 (Russian Federation); Sarov Institute of Physics and Technology (SarFTI) of National Research Nuclear University “MEPhI,” Sarov, Nizhni Novgorod region 607188 (Russian Federation); Maksimov, Artem N.; Pylayev, Nikolay A. [Russian Federal Nuclear Center − All-Russian Scientific and Research Institute of Experimental Physics (RFNC-VNIIEF), Sarov, Nizhni Novgorod region 607188 (Russian Federation)

    2014-09-15

    A glow discharge based device for solving mazes has been designed and tested. The device consists of a gas discharge chamber and maze-transformer of radial-azimuth type. It allows changing of the maze pattern in a short period of time (within several minutes). The device has been tested with low pressure air. Once switched on, a glow discharge has been shown to find the shortest way through the maze from the very first attempt, even if there is a section with potential barrier for electrons on the way. It has been found that ionization waves (striations) can be excited in the maze along the length of the plasma channel. The dependancy of discharge voltage on the length of the optimal path through the maze has been measured. A reduction in discharge voltage with one or two potential barriers present has been found and explained. The dependency of the magnitude of discharge ignition voltage on the length of the optimal path through the maze has been measured. The reduction of the ignition voltage with the presence of one or two potential barriers has been observed and explained.

  7. Spatial and Nonspatial Escape Strategies in the Barnes Maze

    Harrison, Fiona E.; Reiserer, Randall S.; Tomarken, Andrew J.; McDonald, Michael P.

    2006-01-01

    The Barnes maze is a spatial memory task that requires subjects to learn the position of a hole that can be used to escape the brightly lit, open surface of the maze. Two experiments assessed the relative importance of spatial (extra-maze) versus proximal visible cues in solving the maze. In Experiment 1, four groups of mice were trained either…

  8. Die MAZE-Operation zur Behandlung des chronischen Vorhofflimmerns im Langzeitverlauf: 3-Jahres-Ergebnisse

    Aigner C

    2005-01-01

    Full Text Available Grundlagen: Die MAZE-Operation mittels Ablation mit Mikrowelle oder Radiofrequenz ist ein etabliertes Verfahren zur Behandlung des chronischen Vorhofflimmerns. Diese Studie untersucht die Langzeitergebnisse nach 36 Monaten. Methodik: Zwischen 2/2001 und 12/2002 wurden 42 Patienten (64,5 ± 2,2 Jahre; 21 Männer mit chronischem Vorhofflimmern 6 Monate und zusätzlicher teils kombinierter Klappenerkrankung mittels Mitralklappenersatz/-rekonstruktion ± Trikuspidalklappenrekonstruktion (n = 30, Aortenklappenersatz ± Trikuspidalklappenrekonstruktion (n = 6 und Mitralklappen- und Aortenklappenersatz/- rekonstruktion ± Trikuspidalklappenrekonstruktion (n = 6 und MAZE operiert. Die mittlere Dauer des Vorhofflimmerns lag bei 63 ± 29 Monaten (7–384 Monate. Bei der MAZE-Operation wurden, dem Cox-III-Konzept folgend, in beiden Vorhöfen lineare Läsionen mit Mikrowellen- bzw. Radiofrequenzablation gesetzt. Ergebnisse: Die MAZE-Operation führte zu 23 ± 2 Minuten zusätzlicher Aortenklemmzeit (total: 89 ± 3 Min.. Aufgrund eines SIRS war bei einem Patienten der Intensivaufenthalt verlängert. Bei den restlichen Patienten war die Intubationsdauer 18,3 ± 6,7 Stunden, der Intensivaufenthalt 1,7 ± 0,6 Tage. 52,3 % wurden mit Amiodaron behandelt, 64,3 % kardiovertiert. 23,8 % Patienten benötigten einen Schrittmacher wegen eines AV-Blocks bzw. eines Sick-Sinus-Syndroms. Nach 12 Monaten waren 80,8 % frei von Vorhofflimmern. Beim letzten Nachuntersuchungszeitpunkt (36 ± 8 Monate waren 78,6 % frei von Vorhofflimmern. Schlußfolgerungen: Die MAZE-Operation mittels Mikrowellen- bzw. Radiofrequenzablation, folgend dem Cox-III-MAZE-Konzept, erhöht das chirurgische Risiko nur gering. Die Freiheit von Vorhofflimmern ist nach 1 und 3 Jahren praktisch gleich. Es ist also auch langfristig möglich, Patienten mit chronischem Vorhofflimmern einen stabilen Sinusrhythmus zu gewährleisten.

  9. Cryoballoon Catheter Ablation in Atrial Fibrillation

    Cevher Ozcan

    2011-01-01

    Full Text Available Pulmonary vein isolation with catheter ablation is an effective treatment in patients with symptomatic atrial fibrillation refractory or intolerant to antiarrhythmic medications. The cryoballoon catheter was recently approved for this procedure. In this paper, the basics of cryothermal energy ablation are reviewed including its ability of creating homogenous lesion formation, minimal destruction to surrounding vasculature, preserved tissue integrity, and lower risk of thrombus formation. Also summarized here are the publications describing the clinical experience with the cryoballoon catheter ablation in both paroxysmal and persistent atrial fibrillation, its safety and efficacy, and discussions on the technical aspect of the cryoballoon ablation procedure.

  10. Thermal Ablation for Benign Thyroid Nodules: Radiofrequency and Laser

    Baek, Jung Hwan; Lee, Jeong Hyun [University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Valcavi, Roberto [Endocrinology Division and Thyroid Disease Center, Arcispedale Santa Maria Nuova, Reggio Emilia (Italy); Pacella, Claudio M. [Diagnostic Imaging and Interventional Radiology Department, Ospedale Regina Apostolorum, Albano Laziale-Rome (IT); Rhim, Hyun Chul [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Na, Dong Kyu [Human Medical Imaging and Intervention Center, Seoul (Korea, Republic of)

    2011-10-15

    Although ethanol ablation has been successfully used to treat cystic thyroid nodules, this procedure is less effective when the thyroid nodules are solid. Radiofrequency (RF) ablation, a newer procedure used to treat malignant liver tumors, has been valuable in the treatment of benign thyroid nodules regardless of the extent of the solid component. This article reviews the basic physics, techniques, applications, results, and complications of thyroid RF ablation, in comparison to laser ablation.

  11. Optimization of Apparatus Design and Behavioral Measures for the Assessment of Visuo-Spatial Learning and Memory of Mice on the Barnes Maze

    O'Leary, Timothy P.; Brown, Richard E.

    2013-01-01

    We have previously shown that apparatus design can affect visual-spatial cue use and memory performance of mice on the Barnes maze. The present experiment extends these findings by determining the optimal behavioral measures and test procedure for analyzing visuo-spatial learning and memory in three different Barnes maze designs. Male and female…

  12. Cognitive and Neural Determinants of Response Strategy in the Dual-Solution Plus-Maze Task

    De Leonibus, Elvira; Costantini, Vivian J. A.; Massaro, Antonio; Mandolesi, Georgia; Vanni, Valentina; Luvisetto, Siro; Pavone, Flaminia; Oliverio, Alberto; Mele, Andrea

    2011-01-01

    Response strategy in the dual-solution plus maze is regarded as a form of stimulus-response learning. In this study, by using an outcome devaluation procedure, we show that it can be based on both action-outcome and stimulus-response habit learning, depending on the amount of training that the animals receive. Furthermore, we show that…

  13. A randomized study of combining maze surgery for atrial fibrillation with mitral valve surgery

    Jessurun, ER; Van Hemel, NM; Defauw, JJ; De La Riviere, AB; Stofmeel, MAM; Kingma, JH; Ernst, JMPG

    2003-01-01

    Aim Mitral valve surgery seldom suppresses atrial fibrillation (AF), present prior to surgery. Maze III surgery eliminates AF in >80% of cases, the reason why combining this procedure with mitral valve surgery in patients with AF seems worthwhile. We prospectively studied the outcome of combining th

  14. Just add water: cannabinoid discrimination in a water T-maze with FAAH(-/-) and FAAH(+/+) mice.

    Wiley, Jenny L; Lefever, Timothy W; Pulley, Nikita S; Marusich, Julie A; Cravatt, Benjamin F; Lichtman, Aron H

    2016-08-01

    Incomplete overlap in the discriminative stimulus effects of Δ-tetrahydrocannabinol (THC) and the endocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol has been reported in food-reinforced tasks. The aim of this study was to examine cannabinoid discriminative stimulus effects in a nonappetitive procedure. Adult male mice lacking the gene for AEA's major metabolic enzyme, fatty acid amide hydrolase (FAAH), and FAAH mice were trained to discriminate THC or AEA in a water T-maze, in which the response was swimming to an escape platform on the injection-appropriate side. JZL184, a monoacylglycerol lipase inhibitor, was also tested. FAAH mice showed faster acquisition than FAAH mice. THC and AEA fully substituted, with only minor cross-procedure potency variations. Incomplete substitution of JZL184 was observed in THC-trained FAAH mice in the water-maze task, as contrasted with full substitution in a food-reinforced nose-poke procedure. Stress-induced changes in AEA and/or 2-arachidonoylglycerol concentrations in the brain may have mediated this attenuation. JZL184 also partially substituted in AEA-trained FAAH mice in the water maze, suggesting incomplete overlap in the stimulus effects of AEA and JZL184. Through the use of a novel water-maze procedure, the present study supports the work of previous behavioral pharmacologists in showing the robustness of the discrimination paradigm.

  15. Exhumed from thought: basal ganglia and response learning in the plus-maze.

    Packard, Mark G

    2009-04-12

    The plus-maze apparatus figured prominently in the historical debate between cognitive and stimulus-response habit learning theorists concerned with the fundamental question of "what" animals learn. An important feature of this task is that variants of the training procedure can be arranged to allow for an assessment of the relative use of cognitive/place or habit/response learning mechanisms. This brief review describes findings from several neurobiological studies published primarily over the past decade that have re-introduced the plus-maze to investigate the role of the dorsal striatum in learning and memory. Converging evidence from research using brain lesion, pharmacological, and molecular/genetic approaches is described supporting the hypothesis that the dorsolateral striatum plays a selective role in response learning in the plus-maze. Within a multiple systems framework of memory organization, factors that can influence the relative use of place and response learning in the plus-maze are also considered, including the nature of the visual environment, reinforcement/training parameters, and emotional state of the organism. Response learning in the plus-maze may be considered an exemplar task useful for investigating the neurobiological bases of dorsal striatal involvement in habit learning and memory. This mnemonic function of the dorsal striatum generalizes across several sensory modalities and mammalian species, including humans.

  16. Attitudes Towards Catheter Ablation for Atrial Fibrillation

    Vadmann, Henrik; Pedersen, Susanne S; Nielsen, Jens Cosedis;

    2015-01-01

    BACKGROUND: Catheter ablation for atrial fibrillation (AF) is an important but expensive procedure that is the subject of some debate. Physicians´ attitudes towards catheter ablation may influence promotion and patient acceptance. This is the first study to examine the attitudes of Danish...

  17. Analysis of iodinated contrast delivered during thermal ablation: is material trapped in the ablation zone?

    Wu, Po-hung; Brace, Chris L.

    2016-08-01

    Intra-procedural contrast-enhanced CT (CECT) has been proposed to evaluate treatment efficacy of thermal ablation. We hypothesized that contrast material delivered concurrently with thermal ablation may become trapped in the ablation zone, and set out to determine whether such an effect would impact ablation visualization. CECT images were acquired during microwave ablation in normal porcine liver with: (A) normal blood perfusion and no iodinated contrast, (B) normal perfusion and iodinated contrast infusion or (C) no blood perfusion and residual iodinated contrast. Changes in CT attenuation were analyzed from before, during and after ablation to evaluate whether contrast was trapped inside of the ablation zone. Visualization was compared between groups using post-ablation contrast-to-noise ratio (CNR). Attenuation gradients were calculated at the ablation boundary and background to quantitate ablation conspicuity. In Group A, attenuation decreased during ablation due to thermal expansion of tissue water and water vaporization. The ablation zone was difficult to visualize (CNR  =  1.57  ±  0.73, boundary gradient  =  0.7  ±  0.4 HU mm-1), leading to ablation diameter underestimation compared to gross pathology. Group B ablations saw attenuation increase, suggesting that iodine was trapped inside the ablation zone. However, because the normally perfused liver increased even more, Group B ablations were more visible than Group A (CNR  =  2.04  ±  0.84, boundary gradient  =  6.3  ±  1.1 HU mm-1) and allowed accurate estimation of the ablation zone dimensions compared to gross pathology. Substantial water vaporization led to substantial attenuation changes in Group C, though the ablation zone boundary was not highly visible (boundary gradient  =  3.9  ±  1.1 HU mm-1). Our results demonstrate that despite iodinated contrast being trapped in the ablation zone, ablation visibility was

  18. Guiding brine shrimp through mazes by solving reaction diffusion equations

    Singal, Krishma; Fenton, Flavio

    Excitable systems driven by reaction diffusion equations have been shown to not only find solutions to mazes but to also to find the shortest path between the beginning and the end of the maze. In this talk we describe how we can use the Fitzhugh-Nagumo model, a generic model for excitable media, to solve a maze by varying the basin of attraction of its two fixed points. We demonstrate how two dimensional mazes are solved numerically using a Java Applet and then accelerated to run in real time by using graphic processors (GPUs). An application of this work is shown by guiding phototactic brine shrimp through a maze solved by the algorithm. Once the path is obtained, an Arduino directs the shrimp through the maze using lights from LEDs placed at the floor of the Maze. This method running in real time could be eventually used for guiding robots and cars through traffic.

  19. Monitoring of tumor radio frequency ablation using derivative spectroscopy

    Spliethoff, J.W.; Tanis, E.; Evers, Daniel James; Hendriks, B.H.; Prevoo, W.; Ruers, T.J.M.

    2014-01-01

    Despite the widespread use of radio frequency (RF) ablation, an effective way to assess thermal tissue damage during and after the procedure is still lacking. We present a method for monitoring RF ablation efficacy based on thermally induced methemoglobin as a marker for full tissue ablation. Diffus

  20. Memory-Enhancing Activity of Palmatine in Mice Using Elevated Plus Maze and Morris Water Maze

    Dinesh Dhingra

    2012-01-01

    Full Text Available The present study was designed to evaluate the effect of palmatine on memory of Swiss young male albino mice. Palmatine (0.1, 0.5, 1 mg/kg, i.p. and physostigmine (0.1 mg/kg, i.p. per se were administered for 10 successive days to separate groups of mice. Effect of drugs on learning and memory of mice was evaluated using elevated plus maze and Morris water maze. Brain acetylcholinesterase activity was also estimated. Effect of palmatine on scopolamine- and diazepam-induced amnesia was also investigated. Palmatine (0.5 and 1 mg/kg and physostigmine significantly improved learning and memory of mice, as indicated by decrease in transfer latency using elevated plus maze, and decrease in escape latency during training and increase in time spent in target quadrant during retrieval using Morris water maze. The drugs did not show any significant effect on locomotor activity of the mice. Memory-enhancing activity of palmatine (1 mg/kg was comparable to physostigmine. Palmatine (1 mg/kg significantly reversed scopolamine- and diazepam-induced amnesia in mice. Palmatine and physostigmine also significantly reduced brain acetylcholinesterase activity of mice. Thus, palmatine showed memory-enhancing activity in mice probably by inhibiting brain acetylcholinesterase activity, through involvement of GABA-benzodiazepine pathway, and due to its antioxidant activity.

  1. Clustering for Improved Learning in Maze Traversal Problem

    White, Eddie

    2009-01-01

    The maze traversal problem (finding the shortest distance to the goal from any position in a maze) has been an interesting challenge in computational intelligence. Recent work has shown that the cellular simultaneous recurrent neural network (CSRN) can solve this problem for simple mazes. This thesis focuses on exploiting relevant information about the maze to improve learning and decrease the training time for the CSRN to solve mazes. Appropriate variables are identified to create useful clusters using relevant information. The CSRN was next modified to allow for an additional external input. With this additional input, several methods were tested and results show that clustering the mazes improves the overall learning of the traversal problem for the CSRN.

  2. CTS Trials Network: Surgical ablation of atrial fibrillation during mitral valve surgery - many questions unanswered.

    Afifi, Ahmed

    2015-01-01

    A disease that is associated with stroke and mortality, atrial fibrillation (AF) complicates 30 to 50% of mitral valve disease patients admitted for surgery.(1) Since the introduction of the Cox maze III procedure in 1992 many efforts have been made to come up with modified lesion sets and/or energy sources to surgically treat AF. This lead to the recently published American Heart Association (AHA)- American College of Cardiology (ACC)-Heart Rhythm Society (HRS) guidelines(2) stating that it is reasonable to perform atrial fibrillation ablation in selected patients undergoing other types of cardiac surgery. The effectiveness of different techniques in conversion to sinus rhythm and the clinical impact of freedom from AF remain a question. The CTS Trials Network have undertaken a trial to answer these questions. The first year results of their randomized trial comparing AF ablation at the time of mitral valve surgery with mitral valve surgery alone were published recently in The New England Journal of Medicine.(3).

  3. Laser ablation studies of nanocomposites

    Oleg V. Mkrtychev

    2015-03-01

    Full Text Available The first experimental measurements of the threshold energy density values for the laser ablation of glass nanocomposites with nanodimensional coatings have been carried out under the action of the YAG–Nd laser power pulse radiation. The coatings in question were of different compositions and had been created by the sol–gel technology. The procedure for determining the laser ablation threshold energy density values was worked out on the base of the breakdown probability level of 0.5. The statistical processing of the measurement data over all the samples allowed obtaining the dependence of the ablation destruction threshold energy parameters on the coating physical and chemical properties such as the sample transmission in the visible region of the spectrum, coating thickness, the chemical composition of the film-forming solution, and on the pulse duration of laser radiation.

  4. Steerable sheath technology in the ablation of atrial fibrillation.

    Joseph, Jubin; Wong, Kelvin C K; Ginks, Matthew R; Bashir, Yaver; Betts, Timothy R; Rajappan, Kim

    2013-12-01

    Steerable sheaths have been shown to reduce procedure time in the catheter ablation of atrial fibrillation (AF), where catheter positioning and stability is typically challenging. This review critically addresses and highlights the recent developments in design of sheaths used to manipulate the ablation catheter and how these developments may impact on the ablation procedure itself, in particular the likelihood of first-time success. Patents relating to steerable sheaths are reviewed and discussed to gauge potential future developments in this area.

  5. Barnes maze testing strategies with small and large rodent models.

    Rosenfeld, Cheryl S; Ferguson, Sherry A

    2014-02-26

    Spatial learning and memory of laboratory rodents is often assessed via navigational ability in mazes, most popular of which are the water and dry-land (Barnes) mazes. Improved performance over sessions or trials is thought to reflect learning and memory of the escape cage/platform location. Considered less stressful than water mazes, the Barnes maze is a relatively simple design of a circular platform top with several holes equally spaced around the perimeter edge. All but one of the holes are false-bottomed or blind-ending, while one leads to an escape cage. Mildly aversive stimuli (e.g. bright overhead lights) provide motivation to locate the escape cage. Latency to locate the escape cage can be measured during the session; however, additional endpoints typically require video recording. From those video recordings, use of automated tracking software can generate a variety of endpoints that are similar to those produced in water mazes (e.g. distance traveled, velocity/speed, time spent in the correct quadrant, time spent moving/resting, and confirmation of latency). Type of search strategy (i.e. random, serial, or direct) can be categorized as well. Barnes maze construction and testing methodologies can differ for small rodents, such as mice, and large rodents, such as rats. For example, while extra-maze cues are effective for rats, smaller wild rodents may require intra-maze cues with a visual barrier around the maze. Appropriate stimuli must be identified which motivate the rodent to locate the escape cage. Both Barnes and water mazes can be time consuming as 4-7 test trials are typically required to detect improved learning and memory performance (e.g. shorter latencies or path lengths to locate the escape platform or cage) and/or differences between experimental groups. Even so, the Barnes maze is a widely employed behavioral assessment measuring spatial navigational abilities and their potential disruption by genetic, neurobehavioral manipulations, or drug

  6. Development of a 2D laser ablation inductively coupled plasma mass spectrometry mapping procedure for mercury in maize (Zea mays L.) root cross-sections

    Debeljak, Marta [Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna Pot 111, SI-1000 Ljubljana (Slovenia); Elteren, Johannes T. van, E-mail: elteren@ki.si [Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Vogel-Mikuš, Katarina [Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna Pot 111, SI-1000 Ljubljana (Slovenia)

    2013-07-17

    Graphical abstract: -- Highlights: •LA-ICP-MS mapping to study the distribution of Hg in plant root cross-sections. •Sorption of LA-generated Hg vapour leads to serious memory effects. •Spot analysis with a delay time of 10 s in between spots alleviates memory effects. •Ablation straight through the sample simplifies calibration. •Hg{sup 2+} does not cross the endodermal root barrier of maize plants. -- Abstract: A LA-ICP-MS method based on a 213 nm Nd:YAG laser and a quadrupole ICP-MS has been developed for mapping of mercury in root cross-sections of maize (Zea mays L.) to investigate the mechanism of mercury uptake from soil and its potential translocation to the edible parts. Conventional rastering was found to be unusable due to sorption of mercury onto the internal parts of the LA device, giving rising to memory effects resulting in serious loss of resolution and inaccurate quantification. Spot analysis on a virtual grid on the surface of the root sections using washout times of 10 s in between spots greatly alleviated problems related to these memory effects. By ablating straight through the root sections on a poly(methyl methacrylate) support the calibration process was simplified as internal standardization and matrix-matching could be circumvented. Mercury-spiked freeze-drying embedding medium, sectioned similarly to the root sections, was used for the preparation of the standards. Standards and root sections were subjected to spot analysis using the following operational parameters: beam diameter, 15 μm; laser fluence, 2.5 J cm{sup −2}; repetition rate, 20 Hz; dwell time, 1 s; acquisition time, 0.1 s. The mercury peaks for standards and roots sections could be consistently integrated for quantification and construction of the 2D mercury maps for the root sections. This approach was successfully used to investigate the mercury distribution in root sections of maize grown in soil spiked to a level of 50 mg kg{sup −1} DW HgCl{sub 2}. It was

  7. Solving mazes with memristors: A massively parallel approach

    Pershin, Yuriy V.; di Ventra, Massimiliano

    2011-10-01

    Solving mazes is not just a fun pastime: They are prototype models in several areas of science and technology. However, when maze complexity increases, their solution becomes cumbersome and very time consuming. Here, we show that a network of memristors—resistors with memory—can solve such a nontrivial problem quite easily. In particular, maze solving by the network of memristors occurs in a massively parallel fashion since all memristors in the network participate simultaneously in the calculation. The result of the calculation is then recorded into the memristors’ states and can be used and/or recovered at a later time. Furthermore, the network of memristors finds all possible solutions in multiple-solution mazes and sorts out the solution paths according to their length. Our results demonstrate not only the application of memristive networks to the field of massively parallel computing, but also an algorithm to solve mazes, which could find applications in different fields.

  8. Dabigatran in the peri-procedural period for ablation of atrial fibrillation%达比加群酯在心房颤动消融围术期的应用

    潘文麒; 胡文瑛; 林长坚; 张凝; 凌天佑; 吴立群

    2015-01-01

    目的 探讨达比加群酯在心房颤动(房颤)消融围术期抗凝治疗的有效性和安全性.方法 2014年1月至10月在上海交通大学医学院附属瑞金医院共入选进行房颤消融术患者60例,根据围术期抗凝用药不同分为两组,其中华法林组30例,达比加群酯组30例,比较两组患者用药的有效性和安全性.结果 两组患者共有11例发生大小并发症(18.3%).在达比加群酯组中没有严重出血,华法林组中严重出血1例,但两组相比差异无统计学意义(0对3.3%,P>0.05);在达比加群酯组中轻微出血4例,华法林组中轻微出血6例,两组相比差异无统计学意义(13.3%对20%,P>0.05).两组患者均无血栓栓塞事件发生.结论 达比加群酯在房颤消融围术期抗凝治疗与华法林同样有效和安全,可以作为华法林的替代药物.%Objective To evaluated the efficacy and safety of peri-procedural dabigatran in atrial fibrillation(AF) ablation.Methods A total of 60 patients who underwent AF ablation,including 30 patients from Ruijin Hospital,Shanghai Jiaotong University,who received dabigatran(group D)and 30 patients who received warfarin(group W),were evaluated.Results There was no significant difference between the two groups in the incidence of major bleeding(no case of intracranial bleeding in the D group and one case of intracranial bleeding in the W group,0% vs.3.3%,P>0.05)or minor bleeding(four cases in the D group vs.six in the W group,13.3% vs.20%,P>0.05).There were no acute thromboembolic complications in either group.Conclusion Peri-procedural anticoagulation therapy with dabigatran for ablation of AF was equally safe and effective compared with warfarin.Dabigatran appears to be useful as an alternative anticoagulant therapy to warfarin for AF ablation.

  9. ROLE OF RADIOFREQUENCY ABLATION IN ADENOMA SEBACEUM

    Ch. Madh

    2016-03-01

    Full Text Available Adenoma sebaceum, pathognomonic of tuberous sclerosis, are tiny angiofibromas which commonly occur over central part of face. Recurrence after treatment is common and hence a need for inexpensive, safe and efficient treatment is required. Radiofrequency ablation is a safe and an economical procedure and has been known to cause less scarring with good aesthetic results compared to other ablative methods such as electrocautery.

  10. CT-guided Bipolar and Multipolar Radiofrequency Ablation (RF Ablation) of Renal Cell Carcinoma: Specific Technical Aspects and Clinical Results

    Sommer, C. M., E-mail: christof.sommer@med.uni-heidelberg.de [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Lemm, G.; Hohenstein, E. [Minimally Invasive Therapies and Nuclear Medicine, SLK Kliniken Heilbronn GmbH, Clinic for Radiology (Germany); Bellemann, N.; Stampfl, U. [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Goezen, A. S.; Rassweiler, J. [Clinic for Urology, SLK Kliniken Heilbronn GmbH (Germany); Kauczor, H. U.; Radeleff, B. A. [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Pereira, P. L. [Minimally Invasive Therapies and Nuclear Medicine, SLK Kliniken Heilbronn GmbH, Clinic for Radiology (Germany)

    2013-06-15

    Purpose. This study was designed to evaluate the clinical efficacy of CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma (RCC) and to analyze specific technical aspects between both technologies. Methods. We included 22 consecutive patients (3 women; age 74.2 {+-} 8.6 years) after 28 CT-guided bipolar or multipolar RF ablations of 28 RCCs (diameter 2.5 {+-} 0.8 cm). Procedures were performed with a commercially available RF system (Celon AG Olympus, Berlin, Germany). Technical aspects of RF ablation procedures (ablation mode [bipolar or multipolar], number of applicators and ablation cycles, overall ablation time and deployed energy, and technical success rate) were analyzed. Clinical results (local recurrence-free survival and local tumor control rate, renal function [glomerular filtration rate (GFR)]) and complication rates were evaluated. Results. Bipolar RF ablation was performed in 12 procedures and multipolar RF ablation in 16 procedures (2 applicators in 14 procedures and 3 applicators in 2 procedures). One ablation cycle was performed in 15 procedures and two ablation cycles in 13 procedures. Overall ablation time and deployed energy were 35.0 {+-} 13.6 min and 43.7 {+-} 17.9 kJ. Technical success rate was 100 %. Major and minor complication rates were 4 and 14 %. At an imaging follow-up of 15.2 {+-} 8.8 months, local recurrence-free survival was 14.4 {+-} 8.8 months and local tumor control rate was 93 %. GFR did not deteriorate after RF ablation (50.8 {+-} 16.6 ml/min/1.73 m{sup 2} before RF ablation vs. 47.2 {+-} 11.9 ml/min/1.73 m{sup 2} after RF ablation; not significant). Conclusions. CT-guided bipolar and multipolar RF ablation of RCC has a high rate of clinical success and low complication rates. At short-term follow-up, clinical efficacy is high without deterioration of the renal function.

  11. Problem-solving in English through business mazes

    Farthing, Joni

    1981-01-01

    We choose our job carefully. What we cannot choose are our colleagues - so it's not surprising that conflict and friction can arise in our working relationships. Business Mazes presents such problems for you to solve. Follow a route through the maze ans see the outcome of each decision you make. You may find that the quickest rout isn't always the best, or the easiest, in the long run. Business Mazes is designed for intermediate and advanced level students of English, working alone or in groups. It includes full teaching plans and exercises. The mazes may also be used effectively as an interesting approach to discussion for young people preparing their first job.

  12. Fast Escape from Quantum Mazes in Integrated Photonics

    Caruso, Filippo; Ciriolo, Anna Gabriella; Sciarrino, Fabio; Osellame, Roberto

    2015-01-01

    Escaping from a complex maze, by exploring different paths with several decision-making branches in order to reach the exit, has always been a very challenging and fascinating task. Wave field and quantum objects may explore a complex structure in parallel by interference effects, but without necessarily leading to more efficient transport. Here, inspired by recent observations in biological energy transport phenomena, we demonstrate how a quantum walker can efficiently reach the output of a maze by partially suppressing the presence of interference. In particular, we show theoretically an unprecedented improvement in transport efficiency for increasing maze size with respect to purely quantum and classical approaches. In addition, we investigate experimentally these hybrid transport phenomena, by mapping the maze problem in an integrated waveguide array, probed by coherent light, hence successfully testing our theoretical results. These achievements may lead towards future bio-inspired photonics technologies...

  13. A review of the safety aspects of radio frequency ablation

    Abhishek Bhaskaran

    2015-09-01

    Full Text Available In light of recent reports showing high incidence of silent cerebral infarcts and organized atrial arrhythmias following radiofrequency (RF atrial fibrillation (AF ablation, a review of its safety aspects is timely. Serious complications do occur during supraventricular tachycardia (SVT ablations and knowledge of their incidence is important when deciding whether to proceed with ablation. Evidence is emerging for the probable role of prophylactic ischemic scar ablation to prevent VT. This might increase the number of procedures performed. Here we look at the various complications of RF ablation and also the methods to minimize them. Electronic database was searched for relevant articles from 1990 to 2015. With better awareness and technological advancements in RF ablation the incidence of complications has improved considerably. In AF ablation it has decreased from 6% to less than 4% comprising of vascular complications, cardiac tamponade, stroke, phrenic nerve injury, pulmonary vein stenosis, atrio-esophageal fistula (AEF and death. Safety of SVT ablation has also improved with less than 1% incidence of AV node injury in AVNRT ablation. In VT ablation the incidence of major complications was 5–11%, up to 3.4%, up to 1.8% and 4.1–8.8% in patients with structural heart disease, without structural heart disease, prophylactic ablations and epicardial ablations respectively. Vascular and pericardial complications dominated endocardial and epicardial VT ablations respectively. Up to 3% mortality and similar rates of tamponade were reported in endocardial VT ablation. Recent reports about the high incidence of asymptomatic cerebral embolism during AF ablation are concerning, warranting more research into its etiology and prevention.

  14. A Wireless EEG Recording Method for Rat Use inside the Water Maze.

    Richard C Pinnell

    Full Text Available With the continued miniaturisation of portable embedded systems, wireless EEG recording techniques are becoming increasingly prevalent in animal behavioural research. However, in spite of their versatility and portability, they have seldom been used inside water-maze tasks designed for rats. As such, a novel 3D printed implant and waterproof connector is presented, which can facilitate wireless water-maze EEG recordings in freely-moving rats, using a commercial wireless recording system (W32; Multichannel Systems. As well as waterproofing the wireless system, battery, and electrode connector, the implant serves to reduce movement-related artefacts by redistributing movement-related forces away from the electrode connector. This implant/connector was able to successfully record high-quality LFP in the hippocampo-striatal brain regions of rats as they undertook a procedural-learning variant of the double-H water-maze task. Notably, there were no significant performance deficits through its use when compared with a control group across a number of metrics including number of errors and speed of task completion. Taken together, this method can expand the range of measurements that are currently possible in this diverse area of behavioural neuroscience, whilst paving the way for integration with more complex behaviours.

  15. Laser ablation in analytical chemistry - A review

    Russo, Richard E.; Mao, Xianglei; Liu, Haichen; Gonzalez, Jhanis; Mao, Samuel S.

    2001-10-10

    Laser ablation is becoming a dominant technology for direct solid sampling in analytical chemistry. Laser ablation refers to the process in which an intense burst of energy delivered by a short laser pulse is used to sample (remove a portion of) a material. The advantages of laser ablation chemical analysis include direct characterization of solids, no chemical procedures for dissolution, reduced risk of contamination or sample loss, analysis of very small samples not separable for solution analysis, and determination of spatial distributions of elemental composition. This review describes recent research to understand and utilize laser ablation for direct solid sampling, with emphasis on sample introduction to an inductively coupled plasma (ICP). Current research related to contemporary experimental systems, calibration and optimization, and fractionation is discussed, with a summary of applications in several areas.

  16. Imaging in percutaneous ablation for atrial fibrillation

    Maksimovic, Ruzica [Erasmus Medical Center, Department of Radiology, GD Rotterdam (Netherlands); Institute for Cardiovascular Diseases of the University Medical Center, Belgrade (Czechoslovakia); Dill, Thorsten [Kerckhoff-Heart Center, Department of Cardiology, Bad Nauheim (Germany); Ristic, Arsen D.; Seferovic, Petar M. [Institute for Cardiovascular Diseases of the University Medical Center, Belgrade (Czechoslovakia)

    2006-11-15

    Percutaneous ablation for electrical disconnection of the arrhythmogenic foci using various forms of energy has become a well-established technique for treating atrial fibrillation (AF). Success rate in preventing recurrence of AF episodes is high although associated with a significant incidence of pulmonary vein (PV) stenosis and other rare complications. Clinical workup of AF patients includes imaging before and after ablative treatment using different noninvasive and invasive techniques such as conventional angiography, transoesophageal and intracardiac echocardiography, computed tomography (CT) and magnetic resonance imaging (MRI), which offer different information with variable diagnostic accuracy. Evaluation before percutaneous ablation involves assessment of PVs (PV pattern, branching pattern, orientation and ostial size) to facilitate position and size of catheters and reduce procedure time as well as examining the left atrium (presence of thrombi, dimensions and volumes). Imaging after the percutaneous ablation is important for assessment of overall success of the procedure and revealing potential complications. Therefore, imaging methods enable depiction of PVs and the anatomy of surrounding structures essential for preprocedural management and early detection of PV stenosis and other ablation-related procedures, as well as long-term follow-up of these patients. (orig.)

  17. Intelligence-Augmented Rat Cyborgs in Maze Solving

    Yu, Yipeng; Pan, Gang; Gong, Yongyue; Xu, Kedi; Zheng, Nenggan; Hua, Weidong; Zheng, Xiaoxiang; Wu, Zhaohui

    2016-01-01

    Cyborg intelligence is an emerging kind of intelligence paradigm. It aims to deeply integrate machine intelligence with biological intelligence by connecting machines and living beings via neural interfaces, enhancing strength by combining the biological cognition capability with the machine computational capability. Cyborg intelligence is considered to be a new way to augment living beings with machine intelligence. In this paper, we build rat cyborgs to demonstrate how they can expedite the maze escape task with integration of machine intelligence. We compare the performance of maze solving by computer, by individual rats, and by computer-aided rats (i.e. rat cyborgs). They were asked to find their way from a constant entrance to a constant exit in fourteen diverse mazes. Performance of maze solving was measured by steps, coverage rates, and time spent. The experimental results with six rats and their intelligence-augmented rat cyborgs show that rat cyborgs have the best performance in escaping from mazes. These results provide a proof-of-principle demonstration for cyborg intelligence. In addition, our novel cyborg intelligent system (rat cyborg) has great potential in various applications, such as search and rescue in complex terrains. PMID:26859299

  18. Mental walking through a complex maze influences lateralized ultradian rhythms.

    Meier-Koll, A; Albrecht, U; Neuschwander, D

    1998-12-01

    Subjects of two experimental groups, 10 males and 10 females in each group, explored artificial environments represented by compact city mazes. The mazes, a simple and a complex one, were generated by means of a computer program. After turning the program on, a scene with houses, streets, and alleys appeared on a TV screen. The subjects sat in front of the screen and manoeuvered through the simple or the complex maze with the help of a hand-operated device. Correspondingly the street scenes changed in such a way that the subject had the illusion of a normal pace. Each subject explored one maze for eight hours. Every 15 min. an experimenter interrupted the subject's walk and measured tactile discrimination in either hand. Ultradian periodic variations in the tactile error rate of the right and left hands with periods of 2 or 3 hours are found. They are considered manifestations of endogenous rhythms operating separately in the left and right cerebral hemispheres. As demonstrated in a previous paper, lateralized ultradian rhythms in tactile discrimination are different for males and females when tested under quiet laboratory conditions. The present paper shows that the rhythms are specifically influenced in both sexes by the spatial complexity of an artificial environment (maze). These findings are discussed from an evolutionary point of view.

  19. Atrium-atrioventricular node block: an unusual complication during catheter ablation of persistent atrial fibrillation

    MIAO Cheng-long; SANG Cai-hua; DONG Jian-zeng; MA Chang-sheng

    2011-01-01

    Ablation of persistent atrial fibrillation is still a challenge for the ablationist. Extensive ablation is required under some conditions and could lead to some unintended complications. Here we report a case of atrium-atrioventricular node block complicating multiple catheter ablation procedures for persistent atrial fibrillation. After extensive ablation, including circumferential pulmonary vein ablation, linear ablation at the left atrial roof, mitral isthmus, atrial septum, cavotricuspid isthmus, and complex fractionated atrial electrogram ablation, conduction obstacle was found, and sinus impulse could not travel from the right atrium, atrial septum and left atrium to atrioventricular node. The case indicated that intensive ablation at some key sites, especially the interatrial septum, should be careful during ablation of atrial fibrillation.

  20. Feasibility and safety of remote-controlled magnetic navigation for ablation of atrial fibrillation.

    Katsiyiannis, William T; Melby, Daniel P; Matelski, Jayme L; Ervin, Vanessa L; Laverence, Kerri L; Gornick, Charles C

    2008-12-15

    Radiofrequency ablation for atrial fibrillation (AF) involves complex catheter manipulation resulting in prolonged procedure time and fluoroscopy exposure. Remote magnetic navigation (RMN) represents a novel approach toward improving the ability to perform complex ablation. Forty patients underwent ablation for AF, 20 using RMN (NIOBE II, Stereotaxis, Inc) with a 4-mm-tip magnetic catheter (Celsius, Biosense Webster) and 20 using a conventional 8-mm-tip bidirectional ablation catheter (Blazer, Boston Scientific). All patients underwent a combined wide area circumferential ablation and segmental pulmonary vein (PV) isolation using a circular mapping catheter and cavotricuspid isthmus ablation for right atrial flutter. The procedural end point was PV entrance block. There was no difference in atrial size, left ventricular systolic function, or type of AF between groups. PV entrance block was achieved in all patients. Mean procedure time was 279 +/- 60 minutes in the conventional group versus 209 +/- 56 minutes in the RMN group (p RMN group (p RMN group free from clinical AF and off antiarrhythmic drugs (p = NS). There were 2 additional ablations performed for atypical atrial flutter in the conventional group and 3 in the RMN group (p = ns). Ablation catheter char formation was not observed. There were no procedural complications. In conclusion, radiofrequency ablation of AF performed with RMN is safe and feasible. Compared with conventional hand-navigated ablation, RMN ablation results in similar clinical outcomes with decreased fluoroscopy and procedure times.

  1. Catheter ablation of atrial fibrillation in a patient with dextrocardia: what is the challenge?

    WANG Xin-hua; SHI Hai-feng; HAN Bing; TAN Hong-wei; JIANG Wei-feng; LIU Xu

    2010-01-01

    @@ Catheter ablation has been an established strategy for treating paroxysmal atrial fibrillation (AF).Pulmonary vein isolation is the predominant approach of catheter ablation. This procedure is characterized as transseptal catheterization and point-by-point ablation around the ipsilateral pulmonary veins (PVs). Although catheter ablation can be safely performed in a heart with normal structures, it may be challenging to be performed in a dextrocardia.

  2. Laser ablation principles and applications

    1994-01-01

    Laser Ablation provides a broad picture of the current understanding of laser ablation and its many applications, from the views of key contributors to the field. Discussed are in detail the electronic processes in laser ablation of semiconductors and insulators, the post-ionization of laser-desorbed biomolecules, Fourier-transform mass spectroscopy, the interaction of laser radiation with organic polymers, laser ablation and optical surface damage, laser desorption/ablation with laser detection, and laser ablation of superconducting thin films.

  3. Percutaneous thermal ablation of renal neoplasms; Perkutane Thermoablation von Nierentumoren

    Tacke, J. [Inst. fuer Diagnostische und Interventionelle Radiologie/Neuroradiologie, Klinikum Passau (Germany); Mahnken, A.H.; Guenther, R.W. [Klinik fuer Radiologische Diagnostik, Universitaetsklinikum Aachen (Germany)

    2005-12-15

    Due to modern examination techniques such as multidetector computed tomography and high-field magnetic resonance imaging, the detection rate of renal neoplasms is continually increasing. Even though tumors exceeding 4 cm in diameter rarely metastasize, all renal lesions that are possible neoplasms should be treated. Traditional treatment techniques include radical nephrectomy or nephron-sparing resection, which are increasingly performed laparoscopically. Modern thermal ablation techniques such as hyperthermal techniques like radiofrequency ablation RFA, laser induced thermal ablation LITT, focused ultrasound FUS and microwave therapy MW, as well as hypothermal techniques (cryotherapy) may be a useful treatment option for patients who are unfit for or refuse surgical resection. Cryotherapy is the oldest and best known thermal ablation technique and can be performed laparoscopically or percutaneously. Since subzero temperatures have no antistyptic effect, additional maneuvers must be performed to control bleeding. Percutaneous cryotherapy of renal tumors is a new and interesting method, but experience with it is still limited. Radiofrequency ablation is the most frequently used method. Modern probe design allows volumes between 2 and 5 cm in diameter to be ablated. Due to hyperthermal tract ablation, the procedure is deemed to be safe and has a low complication rate. Although there are no randomized comparative studies to open resection, the preliminary results for renal RFA are promising and show RFA to be superior to other thermal ablation techniques. Clinical success rates are over 90% for both, cryo- and radiofrequency ablation. Whereas laser induced thermal therapy is established in hepatic ablation, experience is minimal with respect to renal application. For lesions of more than 2 cm in diameter, additional cooling catheters are required. MR thermometry offers temperature control during ablation. Microwave ablation is characterized by small ablation volumes

  4. [Atrial fibrillation ablation: application of nurse methodology].

    Ramos-González-Serna, Amelia; Mateos-García, M Dolores

    2011-01-01

    Ablation of pulmonary veins for treatment of atrial fibrillation involves applying radiofrequency energy wave by a catheter that causes a circumferential lesion to achieve electrical isolation and voltage drop in the interior. It is mainly applied when there is resistance to treatment and recurrence of symptoms affecting the quality of life of patients. The nurse is an important part of the multidisciplinary team who care for patients who undergo this procedure. The provision of comprehensive nursing care should include nursing procedures prior to, during, and after treatment to ensure the careful and systematic quality required. The aims of this article are: to provide specialised knowledge on the procedure of atrial fibrillation ablation, to describe the preparation of the electrophysiology laboratory, analyse nursing care and develop a standardized care plan for patients on whom this procedure is performed using the NANDA (North American Nursing Association) taxonomy and NIC (Nursing Intervention Classification).

  5. Burn, freeze, or photo-ablate?: comparative symptom profile in Barrett's dysplasia patients undergoing endoscopic ablation

    Gill, Kanwar Rupinder S.; Gross, Seth A.; Greenwald, Bruce D.; Hemminger, Lois L.; Wolfsen, Herbert C.

    2009-06-01

    Background: There are few data available comparing endoscopic ablation methods for Barrett's esophagus with high-grade dysplasia (BE-HGD). Objective: To determine differences in symptoms and complications associated with endoscopic ablation. Design: Prospective observational study. Setting: Two tertiary care centers in USA. Patients: Consecutive patients with BE-HGD Interventions: In this pilot study, symptoms profile data were collected for BE-HGD patients among 3 endoscopic ablation methods: porfimer sodium photodynamic therapy, radiofrequency ablation and low-pressure liquid nitrogen spray cryotherapy. Main Outcome Measurements: Symptom profiles and complications from the procedures were assessed 1-8 weeks after treatment. Results: Ten BE-HGD patients were treated with each ablation modality (30 patients total; 25 men, median age: 69 years (range 53-81). All procedures were performed in the clinic setting and none required subsequent hospitalization. The most common symptoms among all therapies were chest pain, dysphagia and odynophagia. More patients (n=8) in the porfimer sodium photodynamic therapy group reported weight loss compared to radio-frequency ablactation (n=2) and cryotherapy (n=0). Four patients in the porfimer sodium photodynamic therapy group developed phototoxicity requiring medical treatment. Strictures, each requiring a single dilation, were found in radiofrequency ablactation (n=1) and porfimer sodium photodynamic therapy (n=2) patients. Limitations: Small sample size, non-randomized study. Conclusions: These three endoscopic therapies are associated with different types and severity of post-ablation symptoms and complications.

  6. Maze Busters: Carrie Miyoshi Macfarlane & Kathleen Sheehan--Harvard University

    Library Journal, 2004

    2004-01-01

    Even if one is equipped with an MLS, the 11 libraries that comprise the Harvard College Library can be pretty daunting. That is why Carrie Miyoshi Macfarlane and Kathleen Sheehan created Threading the Maze. The online publication is presented to students in expository writing, the one course all undergraduates must take. "This highly effective…

  7. What does the CBM-Maze test measure?

    Muijselaar, M.M.L.; Kendeou, P.; Jong, P.F. de; Broek, P.W. van den

    2017-01-01

    In this study, we identified the code-related (decoding, fluency) and language comprehension (vocabulary, listening comprehension) demands of the CBM-Maze test, a formative assessment, and compared them to those of the Gates-MacGinitie test, a standardized summative assessment. The demands of these

  8. Mazes and Maps: Can Young Children Find Their Way?

    Jirout, Jamie J.; Newcombe, Nora S.

    2014-01-01

    Games provide important informal learning activities for young children, and spatial game play (e.g., puzzles and blocks) has been found to relate to the development of spatial skills. This study investigates 4- and 5-year-old children's use of scaled and unscaled maps when solving mazes, asking whether an important aspect of spatial…

  9. CT-guided radiofrequency tumor ablation in children

    Botsa, Evanthia [National and Kapodistrian University of Athens, First Pediatric Clinic, Agia Sofia Children' s Hospital, Athens (Greece); Poulou, Loukia S.; Koundouraki, Antonia; Thanos, Loukas [Sotiria General Hospital for Chest Diseases, Department of Medical Imaging and Interventional Radiology, Athens (Greece); Koutsogiannis, Ioannis [General Military Hospital NIMTS, Department of Medical Imaging, Athens (Greece); Ziakas, Panayiotis D. [Warren Alpert Medical School of Brown University Rhode Island Hospital, Division of Infectious Diseases, Providence, RI (United States); Alexopoulou, Efthimia [Attikon University Hospital, Second Department of Radiology, Athens University School of Medicine, Athens (Greece)

    2014-11-15

    Image-guided radiofrequency ablation is a well-accepted technique of interventional oncology in adults. To evaluate the efficacy and safety of CT-guided radiofrequency ablation as a minimally invasive treatment for metastatic neoplasms in children. A total of 15 radiofrequency ablation sessions were performed in 12 children and young adults (median age 9.5; range 5-18 years) with metastatic malignancies. Seven children and young adults had secondary hepatic lesions, three had pulmonary and two had bone lesions. Radiofrequency ablation was performed under conscious sedation. The median lesion size was 1.7 cm (range 1.3-2.8 cm). The median time for ablation was 8 min (range 7-10 min). Radiofrequency procedures were technically successful in all tumors. Postablation imaging immediately after, and 1 month and 3 months after radiofrequency ablation showed total necrosis in all patients. At 6-month follow-up, three patients (all with lesion size >2 cm) had local recurrence and underwent a second radiofrequency ablation session. At 2-year follow-up no patient had recurrence of the treated tumor. Post-ablation syndrome occurred in four children. No major complication occurred. CT-guided radiofrequency tumor ablation was safe and efficient for palliative treatment in our cohort of patients. (orig.)

  10. Tests of the Aversive Summation Hypothesis in Rats: Effects of Restraint Stress on Consummatory Successive Negative Contrast and Extinction in the Barnes Maze

    Ortega, Leonardo A.; Prado-Rivera, Mayerli A.; Cardenas-Poveda, D. Carolina; McLinden, Kristina A.; Glueck, Amanda C.; Gutierrez, German; Lamprea, Marisol R.; Papini, Mauricio R.

    2013-01-01

    The present research explored the effects of restraint stress on two situations involving incentive downshift: consummatory successive negative contrast (cSNC) and extinction of escape behavior in the Barnes maze. First, Experiment 1 confirmed that the restraint stress procedure used in these experiments increased levels of circulating…

  11. Percutaneous Microwave Ablation of Renal Angiomyolipomas

    Cristescu, Mircea, E-mail: mcristescu@uwhealth.org [University of Wisconsin, Department of Radiology (United States); Abel, E. Jason, E-mail: abel@urology.wisc.edu [University of Wisconsin, Department of Urology (United States); Wells, Shane, E-mail: swells@uwhealth.org; Ziemlewicz, Timothy J., E-mail: tziemlewicz@uwhealth.org [University of Wisconsin, Department of Radiology (United States); Hedican, Sean P., E-mail: hedican@surgery.wisc.edu [University of Wisconsin, Department of Urology (United States); Lubner, Megan G., E-mail: mlubner@uwhealth.org; Hinshaw, J. Louis, E-mail: jhinshaw@uwhealth.org; Brace, Christopher L., E-mail: cbrace@uwhealth.org; Lee, Fred T., E-mail: flee@uwhealth.org [University of Wisconsin, Department of Radiology (United States)

    2016-03-15

    PurposeTo evaluate the safety and efficacy of US-guided percutaneous microwave (MW) ablation in the treatment of renal angiomyolipoma (AML).Materials and MethodsFrom January 2011 to April 2014, seven patients (5 females and 2 males; mean age 51.4) with 11 renal AMLs (9 sporadic type and 2 tuberous sclerosis associated) with a mean size of 3.4 ± 0.7 cm (range 2.4–4.9 cm) were treated with high-powered, gas-cooled percutaneous MW ablation under US guidance. Tumoral diameter, volume, and CT/MR enhancement were measured on pre-treatment, immediate post-ablation, and delayed post-ablation imaging. Clinical symptoms and creatinine were assessed on follow-up visits.ResultsAll ablations were technically successful and no major complications were encountered. Mean ablation parameters were ablation power of 65 W (range 60–70 W), using 456 mL of hydrodissection fluid per patient, over 4.7 min (range 3–8 min). Immediate post-ablation imaging demonstrated mean tumor diameter and volume decreases of 1.8 % (3.4–3.3 cm) and 1.7 % (27.5–26.3 cm{sup 3}), respectively. Delayed imaging follow-up obtained at a mean interval of 23.1 months (median 17.6; range 9–47) demonstrated mean tumor diameter and volume decreases of 29 % (3.4–2.4 cm) and 47 % (27.5–12.1 cm{sup 3}), respectively. Tumoral enhancement decreased on immediate post-procedure and delayed imaging by CT/MR parameters, indicating decreased tumor vascularity. No patients required additional intervention and no patients experienced spontaneous bleeding post-ablation.ConclusionOur early experience with high-powered, gas-cooled percutaneous MW ablation demonstrates it to be a safe and effective modality to devascularize and decrease the size of renal AMLs.

  12. Post-Ablation Endometrial Carcinoma (PAEC) Following Radiofrequency Endometrial Ablation: A Case Report and Its Implications for Management of Endometrial Ablation Failures.

    Wortman, Morris; Dawkins, Josette C

    2016-10-26

    Endometrial ablation (EA) has become one of the most commonly performed gynecologic procedures in the United States and other developed countries. Global endometrial ablation (GEA) devices have supplanted resectoscopic ablation primarily because they have brought with them technical simplicity and unprecedented safety. These devices, all of which received FDA approval between 1997 and 2001, are typically used to treat abnormal uterine bleeding (AUB) in premenopausal women. Several million women in the US who have undergone a previous EA procedure are about to enter the risk pool for the development of endometrial cancer (EC). Ours is the 18th reported case of post-ablation endometrial carcinoma (PAEC) in the English literature. This case underscores the diagnostic challenges faced in evaluating women with a history of a previous EA who cannot be properly evaluated with conventional techniques such as endometrial biopsy and sonohysterography.

  13. Event-Centered Maze Generation Method for Mobile Virtual Reality Applications

    Kisung Jeong

    2016-11-01

    Full Text Available This study proposes a method of effectively creating mobile virtual reality scenes centered at events for the purpose of providing new experiences in virtual reality environment to users. For this purpose, this paper uses Prim’s maze generation algorithm to automatically create maze environments that have different patterns every time and to compute mazes with finite paths. This paper designs a scheme of creating virtual reality scenes based on event-centered mazes to maximize users’ tension and immersion. Here, event components that are appropriate for the maze environment are defined and maze patterns are created centered at the event point where events that are appropriate for the maze pattern are automatically created. Finally, the paper analyzes whether the proposed virtual reality scene based on event-centered mazes is helpful in enhancing users’ immersion and arousing their interest through diverse experiments.

  14. Photoacoustic characterization of radiofrequency ablation lesions

    Bouchard, Richard; Dana, Nicholas; Di Biase, Luigi; Natale, Andrea; Emelianov, Stanislav

    2012-02-01

    Radiofrequency ablation (RFA) procedures are used to destroy abnormal electrical pathways in the heart that can cause cardiac arrhythmias. Current methods relying on fluoroscopy, echocardiography and electrical conduction mapping are unable to accurately assess ablation lesion size. In an effort to better visualize RFA lesions, photoacoustic (PA) and ultrasonic (US) imaging were utilized to obtain co-registered images of ablated porcine cardiac tissue. The left ventricular free wall of fresh (i.e., never frozen) porcine hearts was harvested within 24 hours of the animals' sacrifice. A THERMOCOOLR Ablation System (Biosense Webster, Inc.) operating at 40 W for 30-60 s was used to induce lesions through the endocardial and epicardial walls of the cardiac samples. Following lesion creation, the ablated tissue samples were placed in 25 °C saline to allow for multi-wavelength PA imaging. Samples were imaged with a VevoR 2100 ultrasound system (VisualSonics, Inc.) using a modified 20-MHz array that could provide laser irradiation to the sample from a pulsed tunable laser (Newport Corp.) to allow for co-registered photoacoustic-ultrasound (PAUS) imaging. PA imaging was conducted from 750-1064 nm, with a surface fluence of approximately 15 mJ/cm2 maintained during imaging. In this preliminary study with PA imaging, the ablated region could be well visualized on the surface of the sample, with contrasts of 6-10 dB achieved at 750 nm. Although imaging penetration depth is a concern, PA imaging shows promise in being able to reliably visualize RF ablation lesions.

  15. 7-NI and ODQ Disturbs Memory in the Elevated Plus Maze, Morris Water Maze, and Radial Arm Maze Tests in Mice.

    Mutlu, Oguz; Akar, Furuzan; Celikyurt, Ipek Komsuoglu; Tanyeri, Pelin; Ulak, Guner; Erden, Faruk

    2015-01-01

    Nitric oxide (NO) is an atypical neurotransmitter that causes changes in cognition. Nitric oxide synthase (NOS) and guanylate cyclase (GC) inhibitors have been shown to exert some effects on cognition in previous studies; however, the findings have been controversial. This study was aimed at understanding the effects of an NOS inhibitor, 7-nitroindazole (7-NI), and a guanylate cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), on spatial memory in modified elevated plus maze (mEPM), Morris water maze (MWM), and radial arm maze (RAM) tests. Male Balb-c mice were treated via intraperitoneal injections with 7-NI (15 mg/kg), ODQ (3, 10 mg/kg), L-arginine (100 mg/kg) + 7-NI (15 mg/kg), or physiological saline. ODQ (3 mg/kg) and 7-NI (15 mg/kg) significantly increased the second-day latency in the mEPM test. 7-NI (15 mg/kg) and ODQ (10 mg/kg) significantly increased the escape latency in second, third, and fourth sessions, decreased the time spent in the escape platform's quadrant, and increased the mean distance to the platform in the probe trial of the MWM test. ODQ (3, 10 mg/kg) and 7-NI (15 mg/kg) significantly increased the number of errors, whereas only 7-NI increased the latency in the RAM test. The administration of L-arginine (100 mg/kg) prior to 7-NI inverted the effects of 7-NI, which supports the role of NO on cognition. Our study shows that the NO/cGMP/GS pathway can regulate spatial memory in mice.

  16. Generalizability Theory Analysis of CBM Maze Reliability in Third- through Fifth-Grade Students

    Mercer, Sterett H.; Dufrene, Brad A.; Zoder-Martell, Kimberly; Harpole, Lauren Lestremau; Mitchell, Rachel R.; Blaze, John T.

    2012-01-01

    Despite growing use of CBM Maze in universal screening and research, little information is available regarding the number of CBM Maze probes needed for reliable decisions. The current study extends existing research on the technical adequacy of CBM Maze by investigating the number of probes and assessment durations (1-3 min) needed for reliable…

  17. Activation of the hippocampal complex during tactile maze solving in congenitally blind subjects

    Gagnon, Léa; Schneider, Fabien C; Siebner, Hartwig R;

    2012-01-01

    imaging (fMRI) in congenitally blind and blindfolded sighted participants while they navigated through a tactile multiple T-maze. Both groups learned the maze task at a similar pace. In blind participants, tactile maze navigation was associated with increased BOLD responses in the right hippocampus...

  18. Moldable cork ablation material

    1977-01-01

    A successful thermal ablative material was manufactured. Moldable cork sheets were tested for density, tensile strength, tensile elongation, thermal conductivity, compression set, and specific heat. A moldable cork sheet, therefore, was established as a realistic product.

  19. Cross-species translation of the Morris maze for Alzheimer's disease.

    Possin, Katherine L; Sanchez, Pascal E; Anderson-Bergman, Clifford; Fernandez, Roland; Kerchner, Geoffrey A; Johnson, Erica T; Davis, Allyson; Lo, Iris; Bott, Nicholas T; Kiely, Thomas; Fenesy, Michelle C; Miller, Bruce L; Kramer, Joel H; Finkbeiner, Steven

    2016-02-01

    Analogous behavioral assays are needed across animal models and human patients to improve translational research. Here, we examined the extent to which performance in the Morris water maze - the most frequently used behavioral assay of spatial learning and memory in rodents - translates to humans. We designed a virtual version of the assay for human subjects that includes the visible-target training, hidden-target learning, and probe trials that are typically administered in the mouse version. We compared transgenic mice that express human amyloid precursor protein (hAPP) and patients with mild cognitive impairment due to Alzheimer's disease (MCI-AD) to evaluate the sensitivity of performance measures in detecting deficits. Patients performed normally during visible-target training, while hAPP mice showed procedural learning deficits. In hidden-target learning and probe trials, hAPP mice and MCI-AD patients showed similar deficits in learning and remembering the target location. In addition, we have provided recommendations for selecting performance measures and sample sizes to make these assays sensitive to learning and memory deficits in humans with MCI-AD and in mouse models. Together, our results demonstrate that with careful study design and analysis, the Morris maze is a sensitive assay for detecting AD-relevant impairments across species.

  20. femtosecond laser ablation

    Margetic, Vanja

    2003-01-01

    Femtosecond laser ablation was investigated as a solid sampling method for elemental chemical analysis. In comparison to the sampling with longer laser pulses, two aspects could be improved by using ultrashort pulses: elimination of the elemental fractionation from the ablation crater, which is necessary for an accurate quantitative analysis, and better control of the material removal (especially for metals), which increases the spatial resolution of microanalysis. Basic aspects of ultrashort...

  1. Outpatient laser tonsillar ablation under local anaesthetic.

    Andrews, Peter J; Latif, Abdul

    2004-11-01

    Outpatient laser ablation of the palatine tonsils under local anaesthetic is an alternative technique to capsular tonsillectomy for recurrent tonsillitis under general anaesthetic. Laser tonsillotomy ablates up to 70% of the tonsillar tissue and is performed when patients choose not to have a conventional tonsillectomy, or are unfit for a general anaesthetic. The technique described here is an adaptation of Krespis' laser-assisted serial tonsillectomy (LAST) whereby only one sitting is required. Krespis' technique effectively eliminates recurrent tonsillitis in 96% of the cases over a 4-year follow-up period and represents the only substantial study looking at treating recurrent tonsillitis with outpatient laser ablation. This study is a retrospective postal survey of 19 patients who underwent laser tonsillar ablation under local anaesthetic for recurrent chronic tonsillitis from 1997 to 2001 and was performed in liaison with the clinical audit department at Basildon Hospital. We had a response rate of 74% and an admission rate of 0%, which compares favourably with day case tonsillectomy surgery. Of the patients, 75% did not experience further episodes of tonsillitis 12 months after the procedure and 77% of the patients were glad they had the operation. Although this technique does not completely eliminate tonsillitis, it offers an alternative for those patients who prefer a procedure that is done quickly in an outpatient setting without the additional problems of general anaesthesia, overnight hospital admission and long waiting lists.

  2. Optimal Navigation of Self-Propelled Colloids in Microstructured Mazes

    Yang, Yuguang; Bevan, Michael

    Controlling navigation of self-propelled microscopic `robots' subject to random Brownian motion in complex microstructured environments (e.g., porous media, tumor vasculature) is important to many emerging applications (e.g., enhanced oil recovery, drug delivery). In this work, we design an optimal feedback policy to navigate an active self-propelled colloidal rod in complex mazes with various obstacle types. Actuation of the rods is modelled based on a light-controlled osmotic flow mechanism, which produces different propulsion velocities along the rod's long axis. Actuator-parameterized Langevin equations, with soft rod-obstacle repulsive interactions, are developed to describe the system dynamics. A Markov decision process (MDP) framework is used for optimal policy calculations with design goals of colloidal rods reaching target end points in minimum time. Simulations show that optimal MDP-based policies are able to control rod trajectories to reach target regions order-of-magnitudes faster than uncontrolled rods, which diverges as maze complexity increases. An efficient multi-graph based implementation for MDP is also presented, which scales linearly with the maze dimension.

  3. Incidence and Cause of Hypertension During Adrenal Radiofrequency Ablation

    Yamakado, Koichiro, E-mail: yama@clin.medic.mie-u.ac.jp; Takaki, Haruyuki [Mie University School of Medicine, Department of Interventional Radiology (Japan); Yamada, Tomomi [Mie University School of Medicine, Department of Translational Medicine (Japan); Yamanaka, Takashi; Uraki, Junji; Kashima, Masataka; Nakatsuka, Atsuhiro; Takeda, Kan [Mie University School of Medicine, Department of Interventional Radiology (Japan)

    2012-12-15

    Purpose: To evaluate the incidence and cause of hypertension prospectively during adrenal radiofrequency ablation (RFA). Methods: For this study, approved by our institutional review board, written informed consent was obtained from all patients. Patients who received RFA for adrenal tumors (adrenal ablation) and other abdominal tumors (nonadrenal ablation) were included in this prospective study. Blood pressure was monitored during RFA. Serum adrenal hormone levels including epinephrine, norepinephrine, dopamine, and cortisol levels were measured before and during RFA. The respective incidences of procedural hypertension (systolic blood pressure >200 mmHg) of the two patient groups were compared. Factors correlating with procedural systolic blood pressure were evaluated by regression analysis.ResultsNine patients underwent adrenal RFA and another 9 patients liver (n = 5) and renal (n = 4) RFA. Asymptomatic procedural hypertension that returned to the baseline by injecting calcium blocker was found in 7 (38.9%) of 18 patients. The incidence of procedural hypertension was significantly higher in the adrenal ablation group (66.7%, 6/9) than in the nonadrenal ablation group (11.1%, 1/9, P < 0.0498). Procedural systolic blood pressure was significantly correlated with serum epinephrine (R{sup 2} = 0.68, P < 0.0001) and norepinephrine (R{sup 2} = 0.72, P < 0.0001) levels during RFA. The other adrenal hormones did not show correlation with procedural systolic blood pressure. Conclusion: Hypertension occurs frequently during adrenal RFA because of the release of catecholamine.

  4. Ultrasound-guided percutaneous thermal ablation of hepatocellular carcinoma using microwave and radiofrequency ablation

    Xu, H.-X.; Xie, X.-Y.; Lu, M.-D. E-mail: lumd@21cn.com; Chen, J.-W.; Yin, X.-Y.; Xu, Z.-F.; Liu, G.-J

    2004-01-01

    AIM: To investigate the therapeutic efficacy of thermal ablation for treatment of hepatocellular carcinoma (HCC) using microwave and radiofrequency (RF) energy application. MATERIALS AND METHODS: A total of 190 nodules in 97 patients (84 male, 13 female; mean age 53.4 years, range 24-74 years) with HCC were treated with microwave or RF ablation in the last 4 years. The applicators were introduced into the tumours under conscious analgesic sedation by intravenous administration of fentanyl citrate and droperidol and local anaesthesia in both thermal ablation procedures. The patients were then followed up with contrast-enhanced computed tomography (CT) to evaluate treatment response. Survival was analysed using the Kaplan-Meier method. RESULTS: Complete ablation was obtained in 92.6% (176/190) nodules. The complete ablation rates were 94.6% (106/112) in microwave ablation and 89.7% (70/78) in RF ablation. The complete ablation rates in tumours{<=}2.0, 2.1-3.9 and {>=}4.0 cm were 93.1, 93.8 and 86.4%, respectively. Local recurrence was found in 9.5% nodules and the rates in tumours{<=}2.0, 2.1-3.9 and {>=}4.0 cm in diameter were 3.4, 9.9 and 31.8%, respectively. In the follow-up period, 7.1% nodules ablated by microwave and 12.8% by RF presented local recurrence. The 1, 2 and 3-year distant recurrence-free survivals were 47.2, 34.9 and 31.0%, respectively. Estimated mean survival was 32 months, and 1, 2 and 3-year cumulative survivals were 75.6, 58.5, and 50.0%, respectively. One and 2 years survivals of Child-Pugh class A, B and C patients were 83.8 and 70.4%, 78.2 and 53.2%, 36.3 and 27.3%, respectively. CONCLUSION: Thermal ablation therapy by means of microwave and RF energy application is an effective and safe therapeutic technique for hepatocellular carcinoma. Large tumours can be completely ablated, but have a significantly higher risk of local recurrence at follow-up.

  5. Analysis of illicit drugs by direct ablation of solid samples.

    Bermúdez, Celina; Cabezas, Carlos; Mata, Santiago; Berdakin, Matias; Tejedor, Jesús M; Alonso, José L

    2015-01-01

    Analysis of illicit drugs arises as an important field of work given the high social impacts presented by drugs in the modern society. Direct laser ablation of solid compounds allows their analysis without sampling or preparation procedures. For that purpose, an experimental set-up that combines laser ablation with time-of- flight mass spectrometry has been constructed very recently to perform studies on the mass spectra of such drugs as 3,4-methylenedioxy-N-methylamphetamine, commonly known as MDMA or ecstasy. Analysis of the observed fragmentation pattern in mass spectra may elucidate the ablation-induced photofragmentation phenomena produced, which differ from those previously observed with conventional ionization methods.

  6. Tumor ablation with irreversible electroporation.

    Bassim Al-Sakere

    Full Text Available We report the first successful use of irreversible electroporation for the minimally invasive treatment of aggressive cutaneous tumors implanted in mice. Irreversible electroporation is a newly developed non-thermal tissue ablation technique in which certain short duration electrical fields are used to permanently permeabilize the cell membrane, presumably through the formation of nanoscale defects in the cell membrane. Mathematical models of the electrical and thermal fields that develop during the application of the pulses were used to design an efficient treatment protocol with minimal heating of the tissue. Tumor regression was confirmed by histological studies which also revealed that it occurred as a direct result of irreversible cell membrane permeabilization. Parametric studies show that the successful outcome of the procedure is related to the applied electric field strength, the total pulse duration as well as the temporal mode of delivery of the pulses. Our best results were obtained using plate electrodes to deliver across the tumor 80 pulses of 100 micros at 0.3 Hz with an electrical field magnitude of 2500 V/cm. These conditions induced complete regression in 12 out of 13 treated tumors, (92%, in the absence of tissue heating. Irreversible electroporation is thus a new effective modality for non-thermal tumor ablation.

  7. Coverage planning in computer-assisted ablation based on Genetic Algorithm.

    Ren, Hongliang; Guo, Weian; Sam Ge, Shuzhi; Lim, Wancheng

    2014-06-01

    An ablation planning system plays a pivotal role in tumor ablation procedures, as it provides a dry run to guide the surgeons in a complicated anatomical environment. Over-ablation, over-perforation or under-ablation may result in complications during the treatments. An optimal solution is desired to have complete tumor coverage with minimal invasiveness, including minimal number of ablations and minimal number of perforation trajectories. As the planning of tumor ablation is a multi-objective problem, it is challenging to obtain optimal covering solutions based on clinician׳s experiences. Meanwhile, it is effective for computer-assisted systems to decide a set of optimal plans. This paper proposes a novel approach of integrating a computational optimization algorithm into the ablation planning system. The proposed ablation planning system is designed based on the following objectives: to achieve complete tumor coverage and to minimize the number of ablations, number of needle trajectories and over-ablation to the healthy tissue. These objectives are taken into account using a Genetic Algorithm, which is capable of generating feasible solutions within a constrained search space. The candidate ablation plans can be encoded in generations of chromosomes, which subsequently evolve based on a fitness function. In this paper, an exponential weight-criterion fitness function has been designed by incorporating constraint parameters that were reflective of the different objectives. According to the test results, the proposed planner is able to generate the set of optimal solutions for tumor ablation problem, thereby fulfilling the aforementioned multiple objectives.

  8. Power Laser Ablation Symposia

    Phipps, Claude

    2007-01-01

    Laser ablation describes the interaction of intense optical fields with matter, in which atoms are selectively driven off by thermal or nonthermal mechanisms. The field of laser ablation physics is advancing so rapidly that its principal results are seen only in specialized journals and conferences. This is the first book that combines the most recent results in this rapidly advancing field with authoritative treatment of laser ablation and its applications, including the physics of high-power laser-matter interaction. Many practical applications exist, ranging from inertial confinement fusion to propulsion of aerostats for pollution monitoring to laser ignition of hypersonic engines to laser cleaning nanoscale contaminants in high-volume computer hard drive manufacture to direct observation of the electronic or dissociative states in atoms and molecules, to studying the properties of materials during 200kbar shocks developed in 200fs. Selecting topics which are representative of such a broad field is difficu...

  9. Transient Ablation of Teflon Hemispheres

    Arai, Norio; Karashima, Kei-ichi; Sato, Kiyoshi

    1997-01-01

    For high-speed entry of space vehicles into atmospheric environments, ablation is a practical method for alleviating severe aerodynamic heating. Several studies have been undertaken on steady or quasi-steady ablation. However, ablation is a very complicated phenomenon in which a nonequilibrium chemical process is associated with an aerodynamic process that involves changes in body shape with time. Therefore, it seems realistic to consider that ablation is an unsteady phenomenon. In the design of an ablative heat-shield system, since the ultimate purpose of the heat shield is to keep the internal temperature of the space vehicle at a safe level during entry, the transient heat conduction characteristics of the ablator may be critical in the selection of the material and its thickness. This note presents an experimental study of transient ablation of Teflon, with particular emphasis on the change in body shape, the instantaneous internal temperature distribution, and the effect of thermal expansion on ablation rate.

  10. Cows in the Maze And other mathematical explorations

    Stewart, Ian

    2010-01-01

    From the mathematics of mazes, to cones with a twist, and the amazing sphericon - and how to make one - Ian Stewart is back with more mathematical stories and puzzles that are as quirky as they are fascinating, and each from the cutting edge of the world of mathematics. We find out about the mathematics of time travel, explore the shape of teardrops (which are not tear-drop shaped, but something much, much more strange!), dance with dodecahedra, and play the game of Hex, amongst many more strange and delightful mathematical diversions.

  11. Tumor ablations in IMRI

    Roberto Blanco Sequeiros

    2002-01-01

    @@ IntroductionMagnetic resonance imaging based guidance control and monitoring of minimally invasive intervention has developed from a hypothetical concept to a practical possibility. Magnetic-resonance-guided interstitial therapy in principle is defined as a treatment technique for ablating deepseated tumors in the human body.

  12. [Anesthetic consideration in patients undergoing catheter ablation for atrial fibrillation].

    Oda, Toshiyuki; Takahama, Yutaka

    2012-11-01

    This chapter describes anesthetic consideration in patients undergoing catheter ablation for atrial fibrillation (AF) based on electrophysiologic or pharmacological aspects. In the 2011 guidelines of the Japanese Circulation Society for non-pharmacotherapy of cardiac arrhythmias, catheter ablation is recommended as Class I therapeutic modality for the patients with drug-refractory paroxysmal AF. Catheter ablation of AF is an invasive and long-lasting procedure necessitating sedation during treatment. However, in the most of the patients, sedation or anesthesia is possibly performed by cardiologists using propofol, midazolam or dexmedetomidine. Deep sedation accompanies a high risk of ventilatory or circulatory derangement. Furthermore, life-threatening complications, such as cerebral infarction or cardiac tamponade, can occur during ablation. Patients with AF are increasing in number as a trend in the aging society, resulting in an increase in catheter ablation in high risk patients. To accomplish safe anesthetic management of the patients for catheter ablations, anesthesiologists are required to have fundamental knowledge and skill in the performance of the catheter ablation.

  13. Actual role of radiofrequency ablation of liver metastases

    Pereira, Philippe L. [Eberhard-Karls-University of Tuebingen, Department of Diagnostic Radiology, Tuebingen (Germany)

    2007-08-15

    The liver is, second only to lymph nodes, the most common site for metastatic disease irrespective of the primary tumour. More than 50% of all patients with malignant diseases will develop liver metastases with a significant morbidity and mortality. Although the surgical resection leads to an improved survival in patients with colorectal metastases, only approximately 20% of patients are eligible for surgery. Thermal ablation and especially radiofrequency ablation emerge as an important additional therapy modality for the treatment of liver metastases. RF ablation shows a benefit in life expectancy and may lead in a selected patient group to cure. Percutaneous RF ablation appears safer (versus cryotherapy), easier (versus laser), and more effective (versus ethanol instillation and transarterial chemoembolisation) compared with other minimally invasive procedures. RF ablation can be performed by a percutaneous, laparoscopical or laparotomic approach, and may be potentially combined with chemotherapy and surgery. At present ideal candidates have tumours with a maximum diameter less than 3.5 cm. An untreatable primary tumour or a systemic disease represents contraindications for performing local therapies. Permanent technical improvements of thermal ablation devices and a better integration of thermal ablation in the overall patient care may lead to prognosis improvement in patients with liver metastases. (orig.)

  14. 2012 HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: recommendations for patient selection, procedural techniques, patient management and follow-up, definitions, endpoints, and research trial design.

    Calkins, Hugh; Kuck, Karl Heinz; Cappato, Riccardo; Brugada, Josep; Camm, A John; Chen, Shih-Ann; Crijns, Harry J G; Damiano, Ralph J; Davies, D Wyn; DiMarco, John; Edgerton, James; Ellenbogen, Kenneth; Ezekowitz, Michael D; Haines, David E; Haissaguerre, Michel; Hindricks, Gerhard; Iesaka, Yoshito; Jackman, Warren; Jalife, Jose; Jais, Pierre; Kalman, Jonathan; Keane, David; Kim, Young-Hoon; Kirchhof, Paulus; Klein, George; Kottkamp, Hans; Kumagai, Koichiro; Lindsay, Bruce D; Mansour, Moussa; Marchlinski, Francis E; McCarthy, Patrick M; Mont, J Lluis; Morady, Fred; Nademanee, Koonlawee; Nakagawa, Hiroshi; Natale, Andrea; Nattel, Stanley; Packer, Douglas L; Pappone, Carlo; Prystowsky, Eric; Raviele, Antonio; Reddy, Vivek; Ruskin, Jeremy N; Shemin, Richard J; Tsao, Hsuan-Ming; Wilber, David

    2012-03-01

    This is a report of the Heart Rhythm Society (HRS) Task Force on Catheter and Surgical Ablation of Atrial Fibrillation, developed in partnership with the European Heart Rhythm Association (EHRA), a registered branch of the European Society of Cardiology and the European Cardiac Arrhythmia Society (ECAS), and in collaboration with the American College of Cardiology (ACC), American Heart Association (AHA), the Asia Pacific Heart Rhythm Society (APHRS), and the Society of Thoracic Surgeons (STS). This is endorsed by the governing bodies of the ACC Foundation, the AHA, the ECAS, the EHRA, the STS, the APHRS, and the HRS.

  15. Atrial Fibrillation Ablation in Systolic Dysfunction: Clinical and Echocardiographic Outcomes

    Tasso Julio Lobo

    2015-01-01

    Full Text Available Background: Heart failure and atrial fibrillation (AF often coexist in a deleterious cycle. Objective: To evaluate the clinical and echocardiographic outcomes of patients with ventricular systolic dysfunction and AF treated with radiofrequency (RF ablation. Methods: Patients with ventricular systolic dysfunction [ejection fraction (EF <50%] and AF refractory to drug therapy underwent stepwise RF ablation in the same session with pulmonary vein isolation, ablation of AF nests and of residual atrial tachycardia, named "background tachycardia". Clinical (NYHA functional class and echocardiographic (EF, left atrial diameter data were compared (McNemar test and t test before and after ablation. Results: 31 patients (6 women, 25 men, aged 37 to 77 years (mean, 59.8±10.6, underwent RF ablation. The etiology was mainly idiopathic (19 p, 61%. During a mean follow-up of 20.3±17 months, 24 patients (77% were in sinus rhythm, 11 (35% being on amiodarone. Eight patients (26% underwent more than one procedure (6 underwent 2 procedures, and 2 underwent 3 procedures. Significant NYHA functional class improvement was observed (pre-ablation: 2.23±0.56; postablation: 1.13±0.35; p<0.0001. The echocardiographic outcome also showed significant ventricular function improvement (EF pre: 44.68%±6.02%, post: 59%±13.2%, p=0.0005 and a significant left atrial diameter reduction (pre: 46.61±7.3 mm; post: 43.59±6.6 mm; p=0.026. No major complications occurred. Conclusion: Our findings suggest that AF ablation in patients with ventricular systolic dysfunction is a safe and highly effective procedure. Arrhythmia control has a great impact on ventricular function recovery and functional class improvement.

  16. Improving Students’ English Pronunciation Ability Through Go Fish Game and Maze Game

    Dwi Astuti Wahyu Nurhayati

    2015-12-01

    Full Text Available The problem highlighted in this research is the low pronunciation ability of Kindergarten students in Al-Irsyad  Madiun  that is caused by (1 the uninteresting activities in learning English; (2 the students' difficulties in pronunciating English words; (3 the students' low motivation in learning. The theoretical review includes the young learners characteristics, games in language, games for young learners. The procedure of the research consists of identifying the problem, planning the action, implementing the action, observing the action, and reflecting the result of the research. In this research, the researcher acts as the teacher who conducts the action research in the classroom and she is helped by the classsroom teacher. In collecting the data, the researcher uses observational technique supported with tests. In analyzing the data, the researcher uses the field notes, teacher's diaries, students ‘work supported with the cassette recording and photograph,then also compares the result of the students' pre-test and post-test to answer the research questions. There is significant improvement in the result of pre-test and post-test of cycle 1 and 2. In cycle 1, t0 (2.55734 is higher than tt (1.73 and in cycle 2, t0 (6.765738 is also higher than tt (1.73. From these two results, therefore, h0 is rejected and the alternative hypothesis (ha is accepted. They practice their pronunciation through taking turn and asking each other for cards to match those they have in their hands, arranging a word and sticking on alphabet, pronunciating the word, giving the meaning, hen making a sentence such as Go Fish Game and Maze Game. By conducting these games, using interesting media, creating various interesting tasks and activities can increase the students' motivation in learning English and pronunciation ability.Keywords: Improving, pronunciation, ability,  go fish and Maze games

  17. A tubular electrode for radiofrequency ablation therapy

    Antunes, Carlos Lemos Lemos Lemos

    2012-07-06

    Purpose – Due to its good mechanical and biocompatibility characteristics, nitinol SEMS is a popular endoprothesis used for relieving stricture problems in hollow organs due to carcinomas. Besides its mechanical application, SEMS can be regarded as well as potential electrode for performing RF ablation therapy on the tumor. The purpose of this work is to perform numerical and experimental analyses in order to characterize the lesion volume induced in biological tissue using this kind of tubular electrode. Design/methodology/approach – Data concerning electrical conductivity and dimension of the damaged tissue after RF ablation procedure were obtained from ex vivo samples. Next, numerical models using 3D finite element method were obtained reassembling the conditions considered at experimentation setup and results were compared. Findings – Numerical and experimental results show that a regular volume of damaged tissue can be obtained considering this type of electrode. Also, results obtained from numerical simulation are close to those obtained by experimentation. Originality/value – SEMSs, commonly used as devices to minimize obstruction problems due to the growth of tumors, may still be considered as an active electrode for RF ablation procedures. A method considering this observation is presented in this paper. Also, numerical simulation can be regarded in this case as a tool for determining the lesion volume.

  18. 'Zero' fluoroscopic exposure for ventricular tachycardia ablation in a patient with situs viscerum inversus totalis.

    Giaccardi, Marzia; Chiodi, Leandro; Del Rosso, Attilio; Colella, Andrea

    2012-03-01

    Situs viscerum inversus totalis (SVIT) is a congenital disorder characterized by mirror reversal of the thoracic and abdominal organs. Different studies have shown that the ablation procedure can be performed without fluoroscopy with safety and effectiveness, in the setting of supraventricular tachycardia. We successfully performed an anatomical map and a radiofrequency catheter ablation of ventricular arrhythmia in a patient with SVIT without fluoroscopy.

  19. CT thermometry for cone-beam CT guided ablation

    DeStefano, Zachary; Abi-Jaoudeh, Nadine; Li, Ming; Wood, Bradford J.; Summers, Ronald M.; Yao, Jianhua

    2016-03-01

    Monitoring temperature during a cone-beam CT (CBCT) guided ablation procedure is important for prevention of over-treatment and under-treatment. In order to accomplish ideal temperature monitoring, a thermometry map must be generated. Previously, this was attempted using CBCT scans of a pig shoulder undergoing ablation.1 We are extending this work by using CBCT scans of real patients and incorporating more processing steps. We register the scans before comparing them due to the movement and deformation of organs. We then automatically locate the needle tip and the ablation zone. We employ a robust change metric due to image noise and artifacts. This change metric takes windows around each pixel and uses an equation inspired by Time Delay Analysis to calculate the error between windows with the assumption that there is an ideal spatial offset. Once the change map is generated, we correlate change data with measured temperature data at the key points in the region. This allows us to transform our change map into a thermal map. This thermal map is then able to provide an estimate as to the size and temperature of the ablation zone. We evaluated our procedure on a data set of 12 patients who had a total of 24 ablation procedures performed. We were able to generate reasonable thermal maps with varying degrees of accuracy. The average error ranged from 2.7 to 16.2 degrees Celsius. In addition to providing estimates of the size of the ablation zone for surgical guidance, 3D visualizations of the ablation zone and needle are also produced.

  20. Percutaneous treatment of hepatocellular carcinoma in patients with cirrhosis: A comparison of the safety of cryoablation and radiofrequency ablation

    Dunne, Ruth M., E-mail: rmdunne@partners.org [Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham and Women' s Hospital, 75 Francis Street, Boston, MA 02115 (United States); Shyn, Paul B., E-mail: pshyn@partners.org [Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham and Women' s Hospital, 75 Francis Street, Boston, MA 02115 (United States); Sung, Jeffrey C., E-mail: jcsung@gmail.com [Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham and Women' s Hospital, 75 Francis Street, Boston, MA 02115 (United States); Tatli, Servet, E-mail: statli@partners.org [Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham and Women' s Hospital, 75 Francis Street, Boston, MA 02115 (United States); Morrison, Paul R. [Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham and Women' s Hospital, 75 Francis Street, Boston, MA 02115 (United States); Catalano, Paul J., E-mail: pcata@jimmy.harvard.edu [Department of Biostatistics and Computational Biology, Dana Farber Cancer Institute, 450 Brookline Avenue, CLSB 11007, Boston, MA 02215 (United States); Department of Biostatistics, Harvard School of Public Health, Boston, MA 02215 (United States); Silverman, Stuart G., E-mail: sgsilverman@partners.org [Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham and Women' s Hospital, 75 Francis Street, Boston, MA 02115 (United States)

    2014-04-15

    Purpose: To compare the safety of image-guided percutaneous cryoablation and radiofrequency ablation in the treatment of hepatocellular carcinoma in patients with cirrhosis. Materials and methods: This retrospective HIPAA-compliant study received institutional review board approval. Forty-two adult patients with cirrhosis underwent image-guided percutaneous ablation of hepatocellular carcinoma from 2003 to 2011. Twenty-five patients underwent 33 cryoablation procedures to treat 39 tumors, and 22 underwent 30 radiofrequency ablation procedures to treat 39 tumors. Five patients underwent both cryoablation and radiofrequency ablation procedures. Complication rates and severity per procedure were compared between the ablation groups. Potential confounding patient, procedure, and tumor-related variables were also compared. Statistical analyses included Kruskal–Wallis, Wilcoxon rank sum, and Fisher's exact tests. Two-sided P-values <0.05 were considered significant. Results: The overall complication rates, 13 (39.4%) of 33 cryoablation procedures versus eight (26.7%) of 30 radiofrequency ablation procedures and severe/fatal complication rates, two (6.1%) of 33 cryoablation procedures versus one (3.3%) of 30 radiofrequency ablation procedures, were not significantly different between the ablation groups (both P = 0.26). Severe complications included pneumothoraces requiring chest tube insertion during two cryoablation procedures. One death occurred within 90 days of a radiofrequency ablation procedure; all other complications were managed successfully. Conclusion: No significant difference was seen in the overall safety of image-guided percutaneous cryoablation and radiofrequency ablation in the treatment of hepatocellular carcinoma in patients with cirrhosis.

  1. Lesion size in relation to ablation site during radiofrequency ablation

    Petersen, H H; Chen, X; Pietersen, A;

    1998-01-01

    convective cooling by induction of a flow around the electrode tip increases lesion dimensions and power consumptions. Furthermore we conclude that for the given target temperature the power consumption is positively correlated with lesion volume (p ...This study was designed to investigate the effect of the convective cooling of the tip of the ablation electrode during temperature controlled radiofrequency ablation. In vivo two different application sites in the left ventricle of anaesthetised pigs were ablated and in vitro ablation...... larger for septal applications than apical applications (p convective cooling by induction of flow yielded larger lesion volume, depth and width (p

  2. Unconscious sedation/analgesia with propofol versus conscious sedation with fentanyl/midazolam for catheter ablation of atrial fibrillation: a prospective, randomized study

    TANG Ri-bo; MA Chang-sheng; DONG Jian-zeng; ZHAO Wen-du; LIU Xing-peng; KANG Jun-ping; LONG De-yong; YU Rong-hui; HU Fu-li; LIU Xiao-hui

    2007-01-01

    @@ Catheter ablation of atrial fibrillation (AF) has been increased dramatically recently.1 However, it is an unpleasant procedure with intolerable pain without sedation. Propofol and fentanyl/midazolam have been widely used in painful clinical examination and cardiovascular procedures with established safety and efficacy.2,3 Propofol, alfentanyl and midazolam were administrated for catheter ablation in some electrophysiological labs for a less painful procedure.4However, there is few published work on the sedation regimen for catheter ablation of AF.

  3. Water maze learning and hippocampal synaptic plasticity in streptozotocin diabetic rats: effects of insulin treatment

    Gispen, W.H.; Biessels, G.J.; Kamal, A.; Urban, I.J.A.; Spruijt, B.M.; Erkelens, D.W.

    1998-01-01

    Streptozotocin-diabetic rats express deficits in water maze learning and hippocampal synaptic plasticity. The present study examined whether these deficits could be prevented and/or reversed with insulin treatment. In addition, the water maze learning deficit in diabetic rats was further characteriz

  4. Effects of Amphetamine and β-Endorphin Fragments on Maze Performance in Rats

    Boer, S. de; Bohus, B.

    1990-01-01

    Fragments of β-endorphin and amphetamine cause similar effects in some tests of maze behavior in rats. The present study served to compare the influence of amphetamine and two β-endorphin fragments [β-endorphin (βE)-(2-9) and βE-(2-16)] on maze behavior in more detail. In Experiment I no significant

  5. Effects of amphetamine and beta-endorphin fragments on maze performance in rats

    Bohus, B; de Boer, S.F.

    1990-01-01

    Fragments of beta-endorphin and amphetamine cause similar effects in some tests of maze behavior in rats. The present study served to compare the influence of amphetamine and two beta-endorphin fragments [beta-endorphin (beta E)-(2-9) and beta E-(2-16)] on maze behavior in more detail. In Experiment

  6. A maze learning comparison of Elman, long short-term memory, and Mona neural networks.

    Portegys, Thomas E

    2010-03-01

    This study compares the maze learning performance of three artificial neural network architectures: an Elman recurrent neural network, a long short-term memory (LSTM) network, and Mona, a goal-seeking neural network. The mazes are networks of distinctly marked rooms randomly interconnected by doors that open probabilistically. The mazes are used to examine two important problems related to artificial neural networks: (1) the retention of long-term state information and (2) the modular use of learned information. For the former, mazes impose a context learning demand: at the beginning of the maze, an initial door choice forms a context that must be remembered until the end of the maze, where the same numbered door must be chosen again in order to reach the goal. For the latter, the effect of modular and non-modular training is examined. In modular training, the door associations are trained in separate trials from the intervening maze paths, and only presented together in testing trials. All networks performed well on mazes without the context learning requirement. The Mona and LSTM networks performed well on context learning with non-modular training; the Elman performance degraded as the task length increased. Mona also performed well for modular training; both the LSTM and Elman networks performed poorly with modular training.

  7. Mini-maze suffices as adjunct to mitral valve surgery in patients with preoperative atrial fibrillation

    Tuinenburg, AE; Van Gelder, IC; Tieleman, RG; Grandjean, JG; Huet, RCG; Van der Maaten, JMAA; Pieper, EG; De Kam, PJ; Ebels, MSCT; Crijns, HJGM

    2000-01-01

    Mini-Maze and Mitral Valve Surgery. Introduction: After mitral valve (MV) surgery, preoperative atrial fibrillation (AF) often recurs while cardioversion therapy generally fails. Additional Cox maze surgery improves postoperative arrhythmia outcome, but the extensive nature of such an approach limit

  8. Ablation, Thermal Response, and Chemistry Program for Analysis of Thermal Protection Systems

    Milos, Frank S.; Chen, Yih-Kanq

    2010-01-01

    In previous work, the authors documented the Multicomponent Ablation Thermochemistry (MAT) and Fully Implicit Ablation and Thermal response (FIAT) programs. In this work, key features from MAT and FIAT were combined to create the new Fully Implicit Ablation, Thermal response, and Chemistry (FIATC) program. FIATC is fully compatible with FIAT (version 2.5) but has expanded capabilities to compute the multispecies surface chemistry and ablation rate as part of the surface energy balance. This new methodology eliminates B' tables, provides blown species fractions as a function of time, and enables calculations that would otherwise be impractical (e.g. 4+ dimensional tables) such as pyrolysis and ablation with kinetic rates or unequal diffusion coefficients. Equations and solution procedures are presented, then representative calculations of equilibrium and finite-rate ablation in flight and ground-test environments are discussed.

  9. Radiofrequency ablation of pulmonary tumors

    Crocetti, Laura, E-mail: l.crocetti@med.unipi.i [Division of Diagnostic Imaging and Intervention, Department of Liver Transplants, Hepatology and Infectious Diseases, Pisa University School of Medicine (Italy); Lencioni, Riccardo [Division of Diagnostic Imaging and Intervention, Department of Liver Transplants, Hepatology and Infectious Diseases, Pisa University School of Medicine (Italy)

    2010-07-15

    The development of image-guided percutaneous techniques for local tumor ablation has been one of the major advances in the treatment of solid tumors. Among these methods, radiofrequency (RF) ablation is currently established as the primary ablative modality at most institutions. RF ablation is accepted as the best therapeutic choice for patients with early-stage hepatocellular carcinoma when liver transplantation or surgical resection are not suitable options and is considered as a viable alternate to surgery for inoperable patients with limited hepatic metastatic disease, especially from colorectal cancer. Recently, RF ablation has been demonstrated to be a safe and valuable treatment option for patients with unresectable or medically inoperable lung malignancies. Resection should remain the standard therapy for non-small cell lung cancer (NSCLC) but RF ablation may be better than conventional external-beam radiation for the treatment of the high-risk individual with NSCLC. Initial favourable outcomes encourage combining radiotherapy and RF ablation, especially for treating larger tumors. In the setting of colorectal cancer lung metastases, survival rates provided by RF ablation in selected patients, are substantially higher than those obtained with any chemotherapy regimens and provide indirect evidence that RF ablation therapy improves survival in patients with limited lung metastatic disease.

  10. Efficacy of percutaneous radiofrequency ablation of osteoid osteoma in children

    Donkol, Ragab H. [Cairo University, Department of Radiology, Faculty of Medicine, Cairo (Egypt); Assir Central Hospital, Department of Radiology, P.O. Box 34, Abha (Saudi Arabia); Al-Nammi, Ahmed [Assir Central Hospital, Department of Radiology, P.O. Box 34, Abha (Saudi Arabia); Moghazi, Khaled [Alexandria University, Faculty of Medicine, Alexandria (Egypt)

    2008-02-15

    Percutaneous radiofrequency (RF) ablation of osteoid osteoma has high technical and clinical success rates. However, there are limited data on its use in the treatment of osteoid osteoma in children. To assess the safety and efficacy of CT-guided percutaneous RF ablation of osteoid osteoma in children and compare the outcomes with published data on its use in patients unselected for age. From January 2003 to July 2006, 23 children with osteoid osteoma were treated with CT-guided RF ablation using a straight rigid electrode. Their mean age was 11 years (range 3.5-16 years) and there were 15 boys and 8 girls. The procedures were carried out under general anaesthesia. Follow-up was performed to assess technical and clinical outcome. The mean follow-up period was 2.5 years (range 13-49 months). Technical success was achieved in 21 children (91.3%). Failure occurred in two children, in one due to failure to adequately localize the nidus within the dense sclerosis and in the other because of a short ablation time (2 min) because he developed hyperthermia. Clinical success was achieved in 18 patients within 2-5 days (primary clinical success rate 78.2%).These patients were allowed to fully weight-bear and function without limitation 1 week after the procedure. Pain recurrence was observed in two patients; one was treated successfully with a second ablation after 6 months (secondary clinical success rate 82.6%). Hyperthermia was observed in two patients during the procedure. Three other minor complications were observed: wound infection in one child and skin burn in two children. No major immediate or delayed complications were observed. Percutaneous CT-guided RF ablation is an effective and safe minimally invasive procedure for the treatment of osteoid osteoma in children. It has high technical and clinical success rates that are slightly lower than those of patients with a wider range of ages. (orig.)

  11. Ablation of solids by femtosecond lasers ablation mechanism and ablation thresholds for metals and dielectrics

    Gamaly, E G; Tikhonchuk, V T; Luther-Davies, B

    2001-01-01

    The mechanism of ablation of solids by intense femtosecond laser pulses is described in an explicit analytical form. It is shown that at high intensities when the ionization of the target material is complete before the end of the pulse, the ablation mechanism is the same for both metals and dielectrics. The physics of this new ablation regime involves ion acceleration in the electrostatic field caused by charge separation created by energetic electrons escaping from the target. The formulae for ablation thresholds and ablation rates for metals and dielectrics, combining the laser and target parameters, are derived and compared to experimental data. The calculated dependence of the ablation thresholds on the pulse duration is in agreement with the experimental data in a femtosecond range, and it is linked to the dependence for nanosecond pulses.

  12. Comparative observation of the therapeutic effect on epiglottis cyst between hypothermia plasma ablation procedure and classic laryngeal surgery with clamp%低温等离子消融术与传统术式治疗会厌囊肿的疗效比较观察

    胡亚娟

    2014-01-01

    Objective To compare the therapeutic effect of low-temperature plasma ablation procedure on epiglottis cyst with that of classic laryngeal surgery with clamp. Methods Included in this report were 42 cases with epiglottis cysts treated in our Hospital during July 2012 to January 2014. They were randomly divided into two groups, i.e. treatment group (TG) treated by low-temperature plasma ablation procedure and control group (CG) treated by classic laryngeal clamp surgery to do cystectomy. The operation was done under general anesthesia through self-retaining laryngoscope equipped with TV monitor among all these cases. They were all followed up for more than 1 year after operation. Then, their clinical therapeutic effect was observed in a comparative way. Results By the end of following up period, no lesion was seen reoccurred in any one case in TG, while reoccurred lesion was found among 19 cases in CG. Furthermore, the surgical procedure with low-temperature plasma ablation held such advantages as less bleeding and less trauma to adjacent normal laryngeal tissue during the operation, short period of post-operative pain and rapid recovery following the surgery. Conclusions The operation of low-temperature plasma ablation is safe and effective for the treatment of epiglottis cyst and worthy promoting to clinical practice.%目的:比较低温等离子消融术与传统手术方法治疗会厌囊肿的临床疗效。方法2012年7月~2014年1月收治的42例会厌囊肿患者,随机分为治疗组和对照组,均在全麻支撑喉镜引导下手术。治疗组采用低温等离子射频消融术,对照组采用喉钳切除术。观察比较两种手术方法的优越性及其临床疗效。结果与传统方法比较,低温等离子手术的手术时间明显缩短、术中出血量明显减少、术后疼痛时间甚短、黏膜修复很快,差异具有统计学意义(P<0.05)。术后随访1年,对照组病变复发19例,而治疗组无1例出

  13. An automated maze task for assessing hippocampus-sensitive memory in mice.

    Pioli, Elsa Y; Gaskill, Brianna N; Gilmour, Gary; Tricklebank, Mark D; Dix, Sophie L; Bannerman, David; Garner, Joseph P

    2014-03-15

    Memory deficits associated with hippocampal dysfunction are a key feature of a number of neurodegenerative and psychiatric disorders. The discrete-trial rewarded alternation T-maze task is highly sensitive to hippocampal dysfunction. Normal mice have spontaneously high levels of alternation, whereas hippocampal-lesioned mice are dramatically impaired. However, this is a hand-run task and handling has been shown to impact crucially on behavioural responses, as well as being labour-intensive and therefore unsuitable for high-throughput studies. To overcome this, a fully automated maze was designed. The maze was attached to the mouse's home cage and the subject earned all of its food by running through the maze. In this study the hippocampal dependence of rewarded alternation in the automated maze was assessed. Bilateral hippocampal-lesioned mice were assessed in the standard, hand-run, discrete-trial rewarded alternation paradigm and in the automated paradigm, according to a cross-over design. A similarly robust lesion effect on alternation performance was found in both mazes, confirming the sensitivity of the automated maze to hippocampal lesions. Moreover, the performance of the animals in the automated maze was not affected by their handling history whereas performance in the hand-run maze was affected by prior testing history. By having more stable performance and by decreasing human contact the automated maze may offer opportunities to reduce extraneous experimental variation and therefore increase the reproducibility within and/or between laboratories. Furthermore, automation potentially allows for greater experimental throughput and hence suitability for use in assessment of cognitive function in drug discovery.

  14. Image-guided radiofrequency ablation of hepatocellular carcinoma (HCC): Is MR guidance more effective than CT guidance?

    Clasen, Stephan, E-mail: stephan.clasen@med.uni-tuebingen.de [University Hospital, Department of Diagnostic and Interventional Radiology, Hoppe-Seyler Str. 3, 72076 Tübingen (Germany); Rempp, Hansjörg, E-mail: hansjoerg.rempp@med.uni-tuebingen.de [University Hospital, Department of Diagnostic and Interventional Radiology, Hoppe-Seyler Str. 3, 72076 Tübingen (Germany); Hoffmann, Rüdiger, E-mail: ruediger.hoffmann@med.uni-tuebingen.de [University Hospital, Department of Diagnostic and Interventional Radiology, Hoppe-Seyler Str. 3, 72076 Tübingen (Germany); Graf, Hansjörg, E-mail: hansjoerg.graf@med.uni-tuebingen.de [University Hospital, Department of Diagnostic and Interventional Radiology, Section of Experimental Radiology, Hoppe-Seyler Str. 3, 72076 Tübingen (Germany); Pereira, Philippe L., E-mail: Philippe.Pereira@slk-kliniken.de [SLK Clinic Heilbronn, Clinic for Radiology, Minimal-invasive Therapies, and Nuclear Medicine, Am Gesundbrunnen 20-26, 74078 Heilbronn (Germany); Claussen, Claus D., E-mail: claus.claussen@med.uni-tuebingen.de [University Hospital, Department of Diagnostic and Interventional Radiology, Hoppe-Seyler Str. 3, 72076 Tübingen (Germany)

    2014-01-15

    Objectives: The purpose of the study was to retrospectively compare technique effectiveness of computed tomography (CT)-guided versus magnetic resonance (MR)-guided radiofrequency (RF) ablation of hepatocellular carcinoma (HCC). Materials and methods: In 35 consecutive patients 53 CT-guided (n = 29) or MR-guided (n = 24) ablation procedures were performed in the treatment of 56 (CT: 29; MR: 27) HCC. The entire ablation procedure was performed at a multislice CT-scanner or an interventional 0.2-Tesla MR-scanner. Assessment of treatment response was based on dynamic MR imaging at 1.5 Tesla. The mean follow-up was 22.9 months. Primary technique effectiveness was assessed 4 months after ablation therapy. Secondary technique effectiveness was assessed 4 months after a facultative second ablation procedure. Primary and secondary technique effectiveness of CT-guided and MR-guided RF ablation was compared by using Chi-Square (likelihood ratio) test. Results: Primary technique effectiveness after a single session was achieved in 26/27 (96.3%) HCC after MR-guided RF ablation and 23/29 (79.3%) HCC after CT-guided RF ablation (Chi-Square: p = 0.04). Secondary technique effectiveness was achieved in 26/27 (96.3%) HCC after MR-guided RF ablation and in 26/29 (89.7%) HCC after CT-guided RF ablation (Chi-Square: p = 0.32). A local tumor progression was detected in 8/52 (15.4%) tumors after initial technique effectiveness. Major complications were detected after 3/53 (5.7%) ablation procedures. Conclusions: CT-guided and MR-guided RF ablations are locally effective therapies in the treatment of HCC. Due to a higher rate of primary technique effectiveness MR-guided RF ablation may reduce the number of required sessions for complete tumor treatment.

  15. Ablation of solids by femtosecond lasers: ablation mechanism and ablation thresholds for metals and dielectrics

    Gamaly, E. G.; Rode, A. V.; Tikhonchuk, V. T.; Luther-Davies, B.

    2001-01-01

    The mechanism of ablation of solids by intense femtosecond laser pulses is described in an explicit analytical form. It is shown that at high intensities when the ionization of the target material is complete before the end of the pulse, the ablation mechanism is the same for both metals and dielectrics. The physics of this new ablation regime involves ion acceleration in the electrostatic field caused by charge separation created by energetic electrons escaping from the target. The formulae ...

  16. Catheter ablation of persistent atrial fibrillation in a patient with dextrocardia

    XUE Zeng-ming; SANG Cai-hua; DONG Jian-zeng; MA Chang-sheng

    2012-01-01

    The technique of catheter ablation for atrial fibrillation (AF) has advanced rapidly over the last ten years.Catheter ablation of AF with special anatomy like dextrocardia was seldomly reported,1,2 which may be difficult for its complex anatomy.Three-dimensional electroanatomical mapping system and image integration system may be helpful during the procedure.We report a case with drug refractory persistent AF and dextrocardia,who underwent an ablation procedure.%Dextrocardia is a rare anomaly where the heart is located on the right side of the chest instead of the normal left side.Ablation of atrial fibrillation (AF) with such an inverted anatomy may be challenging for the manipulation of the catheters.Here we report a case of dextrocardia who underwent ablation for persistent AF guided by image integration system.

  17. Optimization of the generator settings for endobiliary radiofrequency ablation

    Maximilien; Barret; Sarah; Leblanc; Ariane; Vienne; Alexandre; Rouquette; Frederic; Beuvon; Stanislas; Chaussade; Frederic; Prat

    2015-01-01

    AIM:To determine the optimal generator settings for endobiliary radiofrequency ablation. METHODS:Endobiliary radiofrequency ablation was performed in live swine on the ampulla of Vater,the common bile duct and in the hepatic parenchyma. Radiofrequency ablation time,"effect",and power were allowed to vary. The animals were sacrificed two hours after the procedure. Histopathological assessment of the depth of the thermal lesions was performed. RESULTS:Twenty-five radiofrequency bursts were applied in three swine. In the ampulla of Vater(n = 3),necrosis of the duodenal wall was observed starting with an effect set at 8,power output set at 10 W,and a 30 s shot duration,whereas superficial mucosal damage of up to 350 μm in depth was recorded for an effect set at 8,power output set at 6 W and a 30 s shot duration. In the common bile duct(n = 4),a 1070 μm,safe and efficient ablation was obtained for an effect set at 8,a power output of 8 W,and an ablation time of 30 s. Within the hepatic parenchyma(n = 18),the depth of tissue damage varied from 1620 μm(effect = 8,power = 10 W,ablation time = 15 s) to 4480 μm(effect = 8,power = 8 W,ablation time = 90 s). CONCLUSION:The duration of the catheter application appeared to be the most important parameter influencing the depth of the thermal injury during endobiliary radiofrequency ablation. In healthy swine,the currently recommended settings of the generator may induce severe,supratherapeutic tissue damage in the biliary tree,especially in the high-risk area of the ampulla of Vater.

  18. Anatomic approach for ganglionic plexi ablation in patients with paroxysmal atrial fibrillation.

    Katritsis, Demosthenes; Giazitzoglou, Eleftherios; Sougiannis, Demetrios; Goumas, Nicolaos; Paxinos, George; Camm, A John

    2008-08-01

    There is evidence that parasympathetic denervation may prevent atrial fibrillation (AF) recurrences. This study aimed at applying an anatomic approach for ablation of atrial ganglionic plexi (GPs) in patients with paroxysmal AF. Nineteen patients with symptomatic, paroxysmal AF underwent anatomically guided radiofrequency ablation at the location of the 4 main left atrial GPs and were prospectively assessed for recurrence of AF or other atrial arrhythmia. This group was compared with 19 age- and gender-matched patients who previously underwent conventional circumferential pulmonary vein ablation. All ablation procedures were uneventful. Circumferential and GP ablations were accomplished with a radiofrequency delivery time of 28 +/- 5 versus 18 +/- 3 min (p <0.001) and a fluoroscopy time of 31 +/- 5 versus 18 +/- 5 min (p <0.001), respectively. Parasympathetic reflexes during radiofrequency ablation were elicited in 4 patients (21%). Arrhythmia recurred in 7 patients (37%) with circumferential ablation and 14 patients (74%) with GP ablation, during 1-year follow-up (p for log-rank test = 0.017). In 2 patients with GP ablation, left atrial flutters were documented in addition to AF during follow-up. Patients who underwent GP ablation had an almost 2.5 times higher risk of AF recurrence compared with those who underwent circumferential ablation (hazard ratio 2.6, 95% confidence interval 1.0 to 6.6, p = 0.038). In conclusion, anatomically guided GP ablation is feasible and safe in the electrophysiology laboratory, but this approach yields inferior clinical results compared with circumferential ablation.

  19. Emergency bypass post percutaneous atrial ablation: a case report.

    Hargrove, M

    2010-11-01

    A 34-year-old male undergoing percutaneous atrial ablation procedure for paroxysmal fibrillation required emergency sternotomy for cardiac tamponade. The patient had been anticoagulated and had received plavix and aspirin prior to and during the ablation procedure. Seven units of red cell concentrate had been transfused in the cardiac catherisation laboratory. On arrival in theatre, the patient was hypotensive, but was awake on induction of anaesthesia. No recordable blood pressure with non-invasive monitoring was observed. A sternotomy was immediately performed and, on evacuation of the pericardium, a bleeding site was not visible. The patient was commenced on cardiopulmonary bypass. Bleeding site was identified and the defect closed. The patient was weaned from cardiopulmonary bypass with minimal inotropic support and made an uneventful recovery. Bypass time was 38 minutes. A literature review showed a 1% incidence of post-ablation bleeding(1). The incidence of reverting to bypass for such an event has not been reported previously. During these procedures, it might be wise to have the cardiothoracic team notified while atrial ablation procedures are being performed in the cardiac catheterization laboratory.

  20. Percutaneous Renal Tumor Ablation: Radiation Exposure During Cryoablation and Radiofrequency Ablation

    McEachen, James C., E-mail: james.mceachen2@gmail.com [Mayo Clinic, Division of Preventive, Occupational, and Aerospace Medicine (United States); Leng, Shuai; Atwell, Thomas D. [Mayo Clinic, Department of Radiology (United States); Tollefson, Matthew K. [Mayo Clinic, Department of Urology (United States); Friese, Jeremy L. [Mayo Clinic, Department of Radiology (United States); Wang, Zhen; Murad, M. Hassan [Mayo Clinic, Division of Preventive, Occupational, and Aerospace Medicine (United States); Schmit, Grant D. [Mayo Clinic, Department of Radiology (United States)

    2016-02-15

    IntroductionOnce reserved solely for non-surgical cases, percutaneous ablation is becoming an increasingly popular treatment option for a wider array of patients with small renal masses and the radiation risk needs to be better defined as this transition continues.Materials and MethodsRetrospective review of our renal tumor ablation database revealed 425 patients who underwent percutaneous ablation for treatment of 455 renal tumors over a 5-year time period. Imparted radiation dose information was reviewed for each procedure and converted to effective patient dose and skin dose using established techniques. Statistical analysis was performed with each ablative technique.ResultsFor the 331 cryoablation procedures, the mean DLP was 6987 mGycm (SD = 2861) resulting in a mean effective dose of 104.7 mSv (SD = 43.5) and the mean CTDI{sub vol} was 558 mGy (SD = 439) resulting in a mean skin dose of 563.2 mGy (SD = 344.1). For the 124 RFA procedures, the mean DLP was 3485 mGycm (SD = 1630) resulting in a mean effective dose of 50.3 mSv (SD = 24.0) and the mean CTDI{sub vol} was 232 mGy (SD = 149) resulting in a mean skin dose of 233.2 mGy (SD = 117.4). The difference in patient radiation exposure between the two renal ablation techniques was statistically significant (p < 0.001).ConclusionBoth cryoablation and RFA imparted an average skin dose that was well below the 2 Gy deterministic threshold for appreciable sequela. Renal tumor cryoablation resulted in a mean skin and effective radiation dose more than twice that for RFA. The radiation exposure for both renal tumor ablation techniques was at the high end of the medical imaging radiation dose spectrum.

  1. Percutaneous laser ablation of unresectable primary and metastatic adrenocortical carcinoma

    Pacella, Claudio M. [Regina Apostolorum Hospital, Department of Diagnostic Imaging and Interventional Radiology, Via San Francesco 50, Albano Laziale, Rome 00041 (Italy)], E-mail: claudiomaurizio.pacella@fastwebnet.it; Stasi, Roberto; Bizzarri, Giancarlo; Pacella, Sara; Graziano, Filomena Maria; Guglielmi, Rinaldo; Papini, Enrico [Regina Apostolorum Hospital, Department of Diagnostic Imaging and Interventional Radiology, Via San Francesco 50, Albano Laziale, Rome 00041 (Italy)

    2008-04-15

    Purpose: To evaluate the feasibility, safety, and clinical benefits of percutaneous laser ablation (PLA) in patients with unresectable primary and metastatic adrenocortical carcinoma (ACC). Patients and methods: Four patients with hepatic metastases from ACC and a Cushing's syndrome underwent ultrasound-guided PLA. In one case the procedure was performed also on the primary tumor. Results: After three sessions of PLA, the primary tumor of 15 cm was ablated by 75%. After 1-4 (median 1) sessions of PLA, five liver metastases ranging from 2 to 5 cm were completely ablated, while the sixth tumor of 12 cm was ablated by 75%. There were no major complications. Treatment resulted in an improvement of performance status and a reduction of the daily dosage of mitotane in all patients. The three patients with liver metastases presented a marked decrease of 24-h urine cortisol levels, an improved control of hypertension and a mean weight loss of 2.8 kg. After a median follow-up after PLA of 27.0 months (range, 9-48 months), two patients have died of tumor progression, while two other patients remain alive and free of disease. Conclusions: Percutaneous laser ablation is a feasible, safe and well tolerated procedure for the palliative treatment of unresectable primary and metastatic ACC. Further study is required to evaluate the impact of PLA on survival.

  2. Topography-guided custom ablation treatment for treatment of keratoconus

    Rohit Shetty

    2013-01-01

    Full Text Available Keratoconus is a progressive ectatic disorder of the cornea which often presents with fluctuating refraction and high irregular astigmatism. Correcting the vision of these patients is often a challenge because glasses are unable to correct the irregular astigmatism and regular contact lenses may not fit them very well. Topography-guided custom ablation treatment (T-CAT is a procedure of limited ablation of the cornea using excimer laser with the aim of regularizing the cornea, improving the quality of vision and possibly contact lens fit. The aim of the procedure is not to give a complete refractive correction. It has been tried with a lot of success by various groups of refractive surgeons around the world but a meticulous and methodical planning of the procedure is essential to ensure optimum results. In this paper, we attempt to elucidate the planning for a T-CAT procedure for various types of cones and asphericities.

  3. Radiofrequency ablation of osteoid osteoma

    Vanderschueren, Geert Maria Joris Michael

    2009-01-01

    The main purpose of this thesis was to evaluate the effectiveness and safety of CT-guided radiofrequency ablation for the treatment of spinal and non-spinal osteoid osteomas. Furthermore, the technical requirements needed for safe radiofrequency ablation and the clinical outcome after radiofrequency

  4. Laser ablation in analytical chemistry.

    Russo, Richard E; Mao, Xianglei; Gonzalez, Jhanis J; Zorba, Vassilia; Yoo, Jong

    2013-07-02

    In 2002, we wrote an Analytical Chemistry feature article describing the Physics of Laser Ablation in Microchemical Analysis. In line with the theme of the 2002 article, this manuscript discusses current issues in fundamental research, applications based on detecting photons at the ablation site (LIBS and LAMIS) and by collecting particles for excitation in a secondary source (ICP), and directions for the technology.

  5. Radiofrequency ablation of atrial fibrillation

    Wiesfeld, ACP; Tan, ES; Van Veldhuisen, DJ; Crijns, HJGM; Van Gelder, IC

    2004-01-01

    Twenty-five patients (16 males, mean age 46 years.) underwent radiofrequency ablation because of either paroxysmal (13 patients) or persistent atrial fibrillation (12 patients). Ablation aimed at earliest activation of spontaneous and catheter-induced repetitive ectopy in left and right atria and ap

  6. Thermal Ablation for the Treatment of Abdominal Tumors

    2011-01-01

    Percutaneous thermal ablation is an emerging treatment option for many tumors of the abdomen not amenable to conventional treatments. During a thermal ablation procedure, a thin applicator is guided into the target tumor under imaging guidance. Energy is then applied to the tissue until temperatures rise to cytotoxic levels (50-60 °C). Various energy sources are available to heat biological tissues, including radiofrequency (RF) electrical current, microwaves, laser light and ultrasonic waves. Of these, RF and microwave ablation are most commonly used worldwide. During RF ablation, alternating electrical current (~500 kHz) produces resistive heating around the interstitial electrode. Skin surface electrodes (ground pads) are used to complete the electrical circuit. RF ablation has been in use for nearly 20 years, with good results for local tumor control, extended survival and low complication rates1,2. Recent studies suggest RF ablation may be a first-line treatment option for small hepatocellular carcinoma and renal-cell carcinoma3-5. However, RF heating is hampered by local blood flow and high electrical impedance tissues (eg, lung, bone, desiccated or charred tissue)6,7. Microwaves may alleviate some of these problems by producing faster, volumetric heating8-10. To create larger or conformal ablations, multiple microwave antennas can be used simultaneously while RF electrodes require sequential operation, which limits their efficiency. Early experiences with microwave systems suggest efficacy and safety similar to, or better than RF devices11-13. Alternatively, cryoablation freezes the target tissues to lethal levels (-20 to -40 °C). Percutaneous cryoablation has been shown to be effective against RCC and many metastatic tumors, particularly colorectal cancer, in the liver14-16. Cryoablation may also be associated with less post-procedure pain and faster recovery for some indications17. Cryoablation is often contraindicated for primary liver cancer due to

  7. Thermal ablation for the treatment of abdominal tumors.

    Brace, Christopher L; Hinshaw, J Louis; Lubner, Meghan G

    2011-03-07

    Percutaneous thermal ablation is an emerging treatment option for many tumors of the abdomen not amenable to conventional treatments. During a thermal ablation procedure, a thin applicator is guided into the target tumor under imaging guidance. Energy is then applied to the tissue until temperatures rise to cytotoxic levels (50-60 °C). Various energy sources are available to heat biological tissues, including radiofrequency (RF) electrical current, microwaves, laser light and ultrasonic waves. Of these, RF and microwave ablation are most commonly used worldwide. During RF ablation, alternating electrical current (~500 kHz) produces resistive heating around the interstitial electrode. Skin surface electrodes (ground pads) are used to complete the electrical circuit. RF ablation has been in use for nearly 20 years, with good results for local tumor control, extended survival and low complication rates. Recent studies suggest RF ablation may be a first-line treatment option for small hepatocellular carcinoma and renal-cell carcinoma. However, RF heating is hampered by local blood flow and high electrical impedance tissues (eg, lung, bone, desiccated or charred tissue). Microwaves may alleviate some of these problems by producing faster, volumetric heating. To create larger or conformal ablations, multiple microwave antennas can be used simultaneously while RF electrodes require sequential operation, which limits their efficiency. Early experiences with microwave systems suggest efficacy and safety similar to, or better than RF devices. Alternatively, cryoablation freezes the target tissues to lethal levels (-20 to -40 °C). Percutaneous cryoablation has been shown to be effective against RCC and many metastatic tumors, particularly colorectal cancer, in the liver. Cryoablation may also be associated with less post-procedure pain and faster recovery for some indications. Cryoablation is often contraindicated for primary liver cancer due to underlying coagulopathy and

  8. Maze learning by a hybrid brain-computer system

    Wu, Zhaohui; Zheng, Nenggan; Zhang, Shaowu; Zheng, Xiaoxiang; Gao, Liqiang; Su, Lijuan

    2016-09-01

    The combination of biological and artificial intelligence is particularly driven by two major strands of research: one involves the control of mechanical, usually prosthetic, devices by conscious biological subjects, whereas the other involves the control of animal behaviour by stimulating nervous systems electrically or optically. However, to our knowledge, no study has demonstrated that spatial learning in a computer-based system can affect the learning and decision making behaviour of the biological component, namely a rat, when these two types of intelligence are wired together to form a new intelligent entity. Here, we show how rule operations conducted by computing components contribute to a novel hybrid brain-computer system, i.e., ratbots, exhibit superior learning abilities in a maze learning task, even when their vision and whisker sensation were blocked. We anticipate that our study will encourage other researchers to investigate combinations of various rule operations and other artificial intelligence algorithms with the learning and memory processes of organic brains to develop more powerful cyborg intelligence systems. Our results potentially have profound implications for a variety of applications in intelligent systems and neural rehabilitation.

  9. Management of refractory atrial fibrillation post surgical ablation

    Altman, Robert K.; PROIETTI, RICCARDO; Barrett, Conor D.; Paoletti Perini, Alessandro; Santangeli, Pasquale; Danik, Stephan B.; Di Biase, Luigi; Natale, Andrea

    2014-01-01

    Over the past two decades, invasive techniques to treat atrial fibrillation (AF) including catheter-based and surgical procedures have evolved along with our understanding of the pathophysiology of this arrhythmia. Surgical treatment of AF may be performed on patients undergoing cardiac surgery for other reasons (concomitant surgical ablation) or as a stand-alone procedure. Advances in technology and technique have made surgical intervention for AF more widespread. Despite improvements in out...

  10. Using the Morris water maze to assess spatial learning and memory in weanling mice.

    Barnhart, Christopher D; Yang, Dongren; Lein, Pamela J

    2015-01-01

    Mouse models have been indispensable for elucidating normal and pathological processes that influence learning and memory. A widely used method for assessing these cognitive processes in mice is the Morris water maze, a classic test for examining spatial learning and memory. However, Morris water maze studies with mice have principally been performed using adult animals, which preclude studies of critical neurodevelopmental periods when the cellular and molecular substrates of learning and memory are formed. While weanling rats have been successfully trained in the Morris water maze, there have been few attempts to test weanling mice in this behavioral paradigm even though mice offer significant experimental advantages because of the availability of many genetically modified strains. Here, we present experimental evidence that weanling mice can be trained in the Morris water maze beginning on postnatal day 24. Maze-trained weanling mice exhibit significant improvements in spatial learning over the training period and results of the probe trial indicate the development of spatial memory. There were no sex differences in the animals' performance in these tasks. In addition, molecular biomarkers of synaptic plasticity are upregulated in maze-trained mice at the transcript level. These findings demonstrate that the Morris water maze can be used to assess spatial learning and memory in weanling mice, providing a potentially powerful experimental approach for examining the influence of genes, environmental factors and their interactions on the development of learning and memory.

  11. Using the Morris water maze to assess spatial learning and memory in weanling mice.

    Christopher D Barnhart

    Full Text Available Mouse models have been indispensable for elucidating normal and pathological processes that influence learning and memory. A widely used method for assessing these cognitive processes in mice is the Morris water maze, a classic test for examining spatial learning and memory. However, Morris water maze studies with mice have principally been performed using adult animals, which preclude studies of critical neurodevelopmental periods when the cellular and molecular substrates of learning and memory are formed. While weanling rats have been successfully trained in the Morris water maze, there have been few attempts to test weanling mice in this behavioral paradigm even though mice offer significant experimental advantages because of the availability of many genetically modified strains. Here, we present experimental evidence that weanling mice can be trained in the Morris water maze beginning on postnatal day 24. Maze-trained weanling mice exhibit significant improvements in spatial learning over the training period and results of the probe trial indicate the development of spatial memory. There were no sex differences in the animals' performance in these tasks. In addition, molecular biomarkers of synaptic plasticity are upregulated in maze-trained mice at the transcript level. These findings demonstrate that the Morris water maze can be used to assess spatial learning and memory in weanling mice, providing a potentially powerful experimental approach for examining the influence of genes, environmental factors and their interactions on the development of learning and memory.

  12. Planning in human children (Homo sapiens) assessed by maze problems on the touch screen.

    Miyata, Hiromitsu; Itakura, Shoji; Fujita, Kazuo

    2009-02-01

    The authors examined how human children perform on maze tasks on the touch screen and whether the children plan the solution of the mazes. In Experiment 1, the authors exposed children around 3 years of age to a maze having an L-shaped line as a barrier that can be solved by moving an illustration of a dog (the target) to that of a bone (the goal) with their fingers. The participants successfully solved the maze by taking efficient routes more frequently than chance, although the authors found no evidence that a preview of the maze before starting to solve the task facilitated their performance. In Experiment 2, using a plus-shaped maze, the authors found that 3- and 4-year-old children plan and adjust their moves while solving the maze, with 4-year-olds showing more advanced and higher-level planning than 3-year-olds. Similarity of these results to what the authors previously found in pigeons tested in the same tasks may suggest an analogy for planning capacity in the behavioral level across taxa and developmental stages.

  13. Characterization of the rat exploratory behavior in the elevated plus-maze with Markov chains.

    Tejada, Julián; Bosco, Geraldine G; Morato, Silvio; Roque, Antonio C

    2010-11-30

    The elevated plus-maze is an animal model of anxiety used to study the effect of different drugs on the behavior of the animal. It consists of a plus-shaped maze with two open and two closed arms elevated 50cm from the floor. The standard measures used to characterize exploratory behavior in the elevated plus-maze are the time spent and the number of entries in the open arms. In this work, we use Markov chains to characterize the exploratory behavior of the rat in the elevated plus-maze under three different conditions: normal and under the effects of anxiogenic and anxiolytic drugs. The spatial structure of the elevated plus-maze is divided into squares, which are associated with states of a Markov chain. By counting the frequencies of transitions between states during 5-min sessions in the elevated plus-maze, we constructed stochastic matrices for the three conditions studied. The stochastic matrices show specific patterns, which correspond to the observed behaviors of the rat under the three different conditions. For the control group, the stochastic matrix shows a clear preference for places in the closed arms. This preference is enhanced for the anxiogenic group. For the anxiolytic group, the stochastic matrix shows a pattern similar to a random walk. Our results suggest that Markov chains can be used together with the standard measures to characterize the rat behavior in the elevated plus-maze.

  14. Simulation of Pellet Ablation

    Parks, P. B.; Ishizaki, Ryuichi

    2000-10-01

    In order to clarify the structure of the ablation flow, 2D simulation is carried out with a fluid code solving temporal evolution of MHD equations. The code includes electrostatic sheath effect at the cloud interface.(P.B. Parks et al.), Plasma Phys. Contr. Fusion 38, 571 (1996). An Eulerian cylindrical coordinate system (r,z) is used with z in a spherical pellet. The code uses the Cubic-Interpolated Psudoparticle (CIP) method(H. Takewaki and T. Yabe, J. Comput. Phys. 70), 355 (1987). that divides the fluid equations into non-advection and advection phases. The most essential element of the CIP method is in calculation of the advection phase. In this phase, a cubic interpolated spatial profile is shifted in space according to the total derivative equations, similarly to a particle scheme. Since the profile is interpolated by using the value and the spatial derivative value at each grid point, there is no numerical oscillation in space, that often appears in conventional spline interpolation. A free boundary condition is used in the code. The possibility of a stationary shock will also be shown in the presentation because the supersonic ablation flow across the magnetic field is impeded.

  15. Acute effects of ketamine in the holeboard, the elevated-plus maze, and the social interaction test in Wistar rats.

    Silvestre, J S; Nadal, R; Pallarés, M; Ferré, N

    1997-01-01

    Although noncompetitive NMDA receptor antagonists have shown an anxiolyticlike profile in several studies, such effects have not been observed consistently. Previous studies with ketamine, a noncompetitive NMDA antagonist, have employed only shock tests of anxiety based on conflict procedures. In the present experiment, the effect of an acute low dose of ketamine (7 mg/kg) was examined in adult male Wistar rats tested in three nonconflict tests: holeboard, social interaction, and elevated plus-maze paradigms. The results showed that ketamine decreased time spent in active social interaction and the number of rearings and central activity in the social interaction test. It also decreased the number of entries into the percentage of time spent in open arms and the total number of entries in the elevated plus-maze. No significant effect was observed in head dipping in the holeboard test, although the number of crossings did increase. These results suggest an anxiogeniclike effect of ketamine in contrast with results previously described for noncompetitive NMDA receptor antagonists. These effects of ketamine are more similar to those described for stimulant drugs such as caffeine, cocaine, or amphetamine in anxiety tests.

  16. 达比加群酯在房性快速心律失常射频导管消融围术期抗凝治疗中的应用%Safety and efficacy of dabigatran for the peri-procedural anticoagulation in patients undergoing abla-tion of atrial tachyarrhythmias

    周高俊; 郭艳如; 曹克将; 陈明龙; 杨兵; 郦明芳; 张凤祥; 居维竹; 陈红武; 杨刚; 顾凯; 谢欣

    2016-01-01

    Objective To evaluate the safety and efficacy of dabigatran for the peri-procedural antico-agulation in patients with atrial tachyarrhythmias ( ATA) undergoing radiofrequency catheter ablation ( RFCA) . Methods From September 2013 to April 2015,859 patients who underwent RFCA of ATA in the First Affilia-ted Hospital of Nanjing Medical University were retrospectively reviewed. Among them,165 patients administra-ted with dabigatran were defined as Dabigatran group,and another 165 patients taking warfarin matched with age (±3years),sex,type of ATA,and comorbidities were defined as Warfarin group. We evaluated detailed peri-procedural anticoagulation regimens, and compared the incidence of thromboembolic events, major and minor bleeding events and other adverse effects of drugs between these two groups. Results Compared to Warfarin group,Dabigatran group had significantly lower level of the baseline activated clotting time (ACT)[(143. 6± 24. 9)s vs(197. 8±59. 9)s,P0. 05) . The in-cidence of gastrointestinal adverse events was significantly higher in Dabigatran group compared with Warfarin group (9. 1% vs. 0,P0.05)。达比加群酯组胃肠道反应发生率高于华法林组(9.1%对0,P<0.001)。结论达比加群酯可安全有效地用于ATA患者RFCA围术期的抗凝,术中应加强ACT监测。

  17. Unicursal random maze tool path for computer-controlled optical surfacing.

    Wang, Chunjin; Wang, Zhenzhong; Xu, Qiao

    2015-12-01

    A novel unicursal random maze tool path is proposed in this paper, which can not only implement uniform coverage of the polishing surfaces, but also possesses randomness and multidirectionality. The simulation experiments along with the practical polishing experiments are conducted to make the comparison of three kinds of paths, including maze path, raster path, and Hilbert path. The experimental results validate that the maze path can warrant uniform polishing and avoid the appearance of the periodical structures in the polished surface. It is also more effective than the Hilbert path in restraining the mid-spatial frequency error in computer-controlled optical surfacing process.

  18. Comparison of percutaneous cryoablation with microwave ablation in a porcine liver model.

    Niu, Lizhi; Li, Jialiang; Zeng, Jianying; Zhou, Liang; Wang, Song; Zhou, Xulong; Sheng, Lin; Chen, Jibing; Xu, Kecheng

    2014-04-01

    We compared imaging and pathological changes between argon-helium cryosurgical (AH) and microwave (MW) ablation in a porcine liver model. Immediately after ablation, computed tomography (CT) imaging showed that the area affected by MW ablation was considerably greater than that affected by AH ablation; moreover, the surface area of necrotic tissue was considerably greater in the AH group, whereas the depth of the necrotic area was similar. Seven days after ablation, the affected area had not changed much in the AH group, but it had significantly increased in the MW group; similarly, the surface and depth of the necrotic areas had not changed much in the AH group, but they had increased significantly in the MW group. The pathological findings showed similar definitive areas for both groups at both time points. The findings indicated that long time after both therapies, complete tissue necrosis can be achieved, but the extent and depth of necrosis differ: necrosis foci after AH ablation could be predicted by ice ball under CT image, and necrosis foci after MW ablation will increase obviously. MW ablation might therefore be suitable for tumors with a larger volume and simple anatomical structures, and AH ablation might be suitable for tumors with complex anatomical structures or those located near important organs. These two methods could therefore be used in combination in clinical settings, but details of the procedure need to be studied.

  19. Comparison of the Outcomes of Monopolar and Bipolar Radiofrequency Ablation in Surgical Treatment of Atrial Fibrillation

    Wei-zhao Huang; Ying-meng Wu; Hong-yu Ye; Hai-ming Jiang

    2014-01-01

    Objective To compare the therapeutic effects and safety of monopolar and bipolar radiofrequency (RF) ablation used during cardiac surgery to treat atrial fibrillation. Methods We retrospectively studied a total of 81 patients with chronic atrial fibrillation who underwent open cardiac surgery with concomitant RF ablation between January 2007 and March 2011. Fifty-eight patients received bipolar RF ablation and 23 received monopolar RF ablation, respectively. The sinus rhythm restoration rate, the procedural duration, the frequency of severe perioperative complications, and mortality were compared between the two groups. Results The sinus rhythm restoration rate did not differ significantly between the two groups after follow-up of 15.1 ± 12.6 months (P=0.199). The frequencies of severe perioperative complications and mortality were also similar in the two groups. The total procedural time using bipolar RF ablation was significantly shorter than that using monopolar ablation (19.7±4.6 minutes vs. 28.1±8.5 minutes, P Conclusions Both monopolar and bipolar RF ablation are safe and effective in treating chronic atrial fibrillation patients during open cardiac surgery, but bipolar RF ablation is more convenient in practice.

  20. A Seven-year Experience for The Surgical Radiofrequency Ablation in Patients With Atrial Fibrillation

    Bin XIE; Hui-ming GUO; Ruo-bin WU; Cong LU

    2009-01-01

    Objective A 7-year experience for the treatment strategy using mono- and bi-polar radiofrequency (RF) ablation procedures in a heterogeneous group of patients was reported. Methods Between July 2003 and May 2009, the data of 314 consecutive patients aged 13 -75 (48. 70 + 11.09)undergone the radiofrequency ablation procedure for atrial fibrillation (AF) associated with concomitant cardiac surgery were analyzed. Monopolar was used for 91 patients; Medtronic bi-polar RF ablation procedure for 92 patients and Atricure RF ablation procedure for 131 patients. All patients were combined with valve surgery. Regular follow-ups were performed at 3, 6 month after surgery. Results Hospital mortality after combined open heart and surgical RF ablation was 0 %. The success rates for sinus rhythm con-version with monopolar RF were 73.6 % immediately, 74. 7 % at 3 months, 79. 1% at 6 months; with Medtronic bi-polar RF, the rates were 78.3 % immediately, 82. 8 % at 3 months, 84 % at 6 months; with Atricure bi-polar RF, the rates were 82. 4 % immediately, 84. 1% at 3 months, 83.9 % at 6 months. Conclusions The use of RF ablation pro-cedures is a safe and efficient option to cure AF during open heart surgery in a selective group of patients.

  1. Ablative fractional laser resurfacing helps treat restrictive pediatric scar contractures.

    Krakowski, Andrew C; Goldenberg, Alina; Eichenfield, Lawrence F; Murray, Jill-Peck; Shumaker, Peter R

    2014-12-01

    Conventional management of debilitating pediatric scar contractures, including hand therapy and surgery, may often be beset by delayed treatment, suboptimal results, and additional surgical morbidity. Ablative fractional laser resurfacing is an emerging adjunctive procedural option for scar contractures because of its promising efficacy and safety profile. However, its use to improve function has not been studied in the pediatric population. Herein we report 2 pediatric patients with recalcitrant scar contractures, causing persistent functional deficits, treated with an ablative fractional laser protocol. Both patients experienced rapid and cumulative subjective and objective improvements in range of motion and function as measured by an independent occupational therapist without reported complications. We highlight ablative fractional laser resurfacing as a novel and promising tool in the management of function-limiting scar contractures in children and propose that the technique be incorporated into existing scar treatment paradigms, guided by future research.

  2. Slime mould solves maze in one pass ... assisted by gradient of chemo-attractants

    Adamatzky, Andrew

    2011-01-01

    Plasmodium of Physarum polycephalum is a large cell, visible by unaided eye, which exhibits sophisticated patterns of foraging behaviour. The plasmodium's behaviour is well interpreted in terms of computation, where data are spatially extended configurations of nutrients and obstacles, and results of computation are networks of protoplasmic tubes formed by the plasmodium. In laboratory experiments and numerical simulation we show that if plasmodium of Physarum is inoculated in a maze's peripheral channel and an oat flake (source of attractants) in a the maze's central chamber then the plasmodium grows toward target oat flake and connects the flake with the site of original inoculation with a pronounced protoplasmic tube. The protoplasmic tube represents a path in the maze. The plasmodium solves maze in one pass because it is assisted by a gradient of chemo-attractants propagating from the target oat flake.

  3. Magnetic and robotic navigation for catheter ablation: "joystick ablation".

    Ernst, Sabine

    2008-10-01

    Catheter ablation has become the treatment of choice to cure various arrhythmias in the last decades. The newest advancement of this general concept is made on the navigation ability using remote-controlled ablation catheters. This review summarizes the concept of the two currently available systems, followed by a critical review of the published clinical reports for each system, respectively. Despite the limited amount of data, an attempt to compare the two systems is made.

  4. Active Brownian particles and run-and-tumble particles separate inside a maze

    Khatami, Maryam; Wolff, Katrin; Pohl, Oliver; Ejtehadi, Mohammad Reza; Stark, Holger

    2016-11-01

    A diverse range of natural and artificial self-propelled particles are known and are used nowadays. Among them, active Brownian particles (ABPs) and run-and-tumble particles (RTPs) are two important classes. We numerically study non-interacting ABPs and RTPs strongly confined to different maze geometries in two dimensions. We demonstrate that by means of geometrical confinement alone, ABPs are separable from RTPs. By investigating Matryoshka-like mazes with nested shells, we show that a circular maze has the best filtration efficiency. Results on the mean first-passage time reveal that ABPs escape faster from the center of the maze, while RTPs reach the center from the rim more easily. According to our simulations and a rate theory, which we developed, ABPs in steady state accumulate in the outermost region of the Matryoshka-like mazes, while RTPs occupy all locations within the maze with nearly equal probability. These results suggest a novel technique for separating different types of self-propelled particles by designing appropriate confining geometries without using chemical or biological agents.

  5. Ultrasound-guided radiofrequency ablation of thyroid gland: a preliminary study in dogs

    Choi, Ji Won; Yoo, Seung Min [College of Medicine, Chungang University, Seoul, (Korea, Republic of); Kwak, Seo Hyun [Seoul Veterans Hospital, Seoul (Korea, Republic of)

    2005-07-15

    The purpose of this study was to evaluate the possibility of using radiofrequency ablation as the treatment modality for the benign or malignant thyroid nodules in humans. Therefore, we examined the results of using radiofrequency ablation on the thyroid glands in dogs, in respect of the extent of the ablated tissue and the complications. Five dogs (10 lobes of the thyroid glands) were included in this study. US-guided radiofrequency ablation was undertaken with a 10 mm, uncovered 17 gauge cool-tip needle. The power and duration was 20 wattage and 1 minute in five thyroid lobes (group 1) and 20 wattage and 2 minutes in another 5 thyroid lobes (group 2). The ultrasound scans and the pre-and post-enhancement CT scans were undertaken before and immediately after the procedures, and at 24 hours, 72 hours and 1 week later. The US and CT findings of the ablated tissue and complications were evaluated. Blood sampling was done at the pre-procedure time and 1 week later for evaluating the functional status of the thyroid gland. Laryngoscopy was done at the pre-procedure and post-procedure times, and at 24 hours, 72 hours and 1 week later for the evaluation of any recurrent laryngeal nerve palsy. The echo pattern of the ablated thyroid gland at immediately after the radiofrequency ablation appeared as poorly marginated and hyperechoic. On the US obtained 24 hours after radiofrequency ablation, the echo pattern of the ablated thyroid gland was hypoechoic. The maximum diameters after RFA were 9.4 {rho} 0.5 mm in group I and 11.4 {rho} 0.5 mm in group II. The pre-enhanced CT scan taken at immediately after the radiofrequency ablation showed ill defined hypodense areas in the ablated thyroid gland. Differentiation between the normal and abnormal portions of the thyroid gland was difficult on the contrast enhanced CT scan. Complications induced by radiofrequency ablation were one recurrent laryngeal nerve palsy, two perforations of esophagus and five thickenings of the esophageal

  6. Initial experience with circumferential pulmonary vein ablation guided by fusion of magnetic resonance imaging with three-dimensional electroanatomic mapping

    TANG Kai; MA Jian; MA Fu-sheng; JlA Yu-he; ZHANG Shu

    2006-01-01

    @@ Catheter ablation for the treatment of atrial fibrillation (AF) has been a focal target of electrophysiological study in recent years. Up to date,circumferential pulmonary vein ablation (CPVA)guided by three-dimensional (3-D) electroanatomic mapping (Carto, USA) has been one of the most favourable procedures for the treatment of AF.

  7. Three-dimension finite-element analyses of multiple electrodes bipolar RF global endometrial ablation

    Hu, Tao; Panhao, Tang; Xiao, Jiahua

    2015-03-01

    Radio-frequency ablation (RFA) is a minimally invasive surgical procedure to thermally ablate the targeted diseased tissue. There have been many finite-element method (FEM) studies of cardiac and hepatic RFA, but hardly find any FEM study on endometrial ablation for abnormal uterine bleeding. In this paper, a FEM model was generated to analyze the temperature distribution of bipolar RF global endometrial ablation with three pairs of bipolar electrodes placed at the perimeter of the uterine cavity. COMSOL was utilized to calculate the RF electric fields and temperature fields by numerically solving the bioheat equation in the triangle uterine cavity range. The 55°C isothermal surfaces show the shape of the ablation dimensions (depth and width), which reasonably matched the experimental results.

  8. Chemical nonequilibrium Navier-Stokes solutions for hypersonic flow over an ablating graphite nosetip

    Chen, Y. K.; Henline, W. D.

    1993-01-01

    The general boundary conditions including mass and energy balances of chemically equilibrated or nonequilibrated gas adjacent to ablating surfaces have been derived. A computer procedure based on these conditions was developed and interfaced with the Navier-Stokes solver for predictions of the flow field, surface temperature, and surface ablation rates over re-entry space vehicles with ablating Thermal Protection Systems (TPS). The Navier-Stokes solver with general surface thermochemistry boundary conditions can predict more realistic solutions and provide useful information for the design of TPS. A test case with a proposed hypersonic test vehicle configuration and associated free stream conditions was developed. Solutions with various surface boundary conditions were obtained, and the effect of nonequilibrium gas as well as surface chemistry on surface heating and ablation rate were examined. The solutions of the GASP code with complete ablating surface conditions were compared with those of the ASC code. The direction of future work is also discussed.

  9. Field enhancement induced laser ablation

    Fiutowski, Jacek; Maibohm, Christian; Kjelstrup-Hansen, Jakob

    Sub-diffraction spatially resolved, quantitative mapping of strongly localized field intensity enhancement on gold nanostructures via laser ablation of polymer thin films is reported. Illumination using a femtosecond laser scanning microscope excites surface plasmons in the nanostructures...

  10. Effects of an early experience involving training in a T-maze under either denial or receipt of expected reward through maternal contact.

    Antonios eStamatakis

    2013-11-01

    Full Text Available The mother is the most salient stimulus for the developing pups and a number of early experience models employ manipulation of the mother-infant interaction. We have developed a new model which in addition to changes in maternal behavior includes a learning component on the part of the pups. More specifically, pups were trained in a T-maze and either received (RER rats or were denied (DER the reward of maternal contact, during postnatal days 10—13.Pups of both experimental groups learn the T-maze, but the RER do so more efficiently utilizing a procedural-type of learning and memory with activation of the dorsal basal ganglia. On the other hand, the DER experience leads to activation of the hippocampus, prefrontal cortex and amygdala in the pups.In adulthood, male DER animals exhibit better mnemonic abilities in the Morris water maze and higher activation of the hippocampus, while they have decreased brain serotonergic activity, exhibit a depressive-like phenotype and proactive aggressive behavior in the resident-intruder test. On the other hand, male RER animals assume a reactive coping style in this test, showed increased emotionality as well as freezing in the memory test following both contextual and cued fear conditioning.

  11. Evaluation of neurotransmitters involved in the anxiolytic and panicolytic effect of the aqueous fraction of Paullinia cupana (guaraná in elevated T maze

    Marcel P. Rangel

    2013-04-01

    Full Text Available This study investigated the effects of repeatedly administration of an aqueous fraction of Paullinia cupana Kunth, Sapindaceae (guaraná seeds (8 mg/kg on rats submitted to the elevated T-maze, model of generalized anxiety and panic disorders. The selective serotonin reuptake inhibitor paroxetine (3 mg/kg, was used as a positive control. To evaluate possible neurotransmissions involvement, ineffective doses of metergoline (3 mg/kg - non-selective serotonin receptor antagonist, sulpiride (20 mg/kg - non-selective dopaminergic receptor antagonist or ketamine (0.125 mg/kg - non-selective glutamate receptor antagonist were acutely administered in association with the aqueous fraction of P. cupana. Both aqueous fraction and paroxetine decrease the inhibitory avoidance latencies of the elevated T-maze, indicating anxiolytic effect and increased one-way escape latencies from the open arm of the elevated T-maze, indicating a panicolytic effect. The pre-treatment with metergoline, sulpiride and ketamine blocked the anxiolytic effect of aqueous fraction. The panicolytic effect of aqueous fraction was blocked by both metergoline and sulpiride. These results show that the serotonergic, dopaminergic and glutamatergic neurotransmission systems are involved in anxiolytic effect promoted by aqueous fraction, whereas only the serotonergic and the dopaminergic neurotransmission systems are involved in the panicolytic effect promoted by aqueous fraction of P. cupana. The effects produced by paroxetine, were blocked only by metergoline, validating this experimental procedure.

  12. Structural and functional atrial remodeling in patients after catheter and surgical ablation of atrial fibrillation

    Bockeria L.A.

    2016-03-01

    Full Text Available Atrial fibrillation (AF is the most common supraventricular arrhythmia which occurs in 1.5–2.0% of population. Morbidity of AF increased by 13% over the past two decades. Modern treatment of AF includes drug therapy, catheter radiofrequency ablation and various modifications of Cox Maze operations. The purpose of this review was to assess the atrial remodeling according to world literature. This involved a search of published articles in Medline, Web of Science, PubMed, Cochrane Central Register of Controlled Trials medical databases. During the primary stage of analysis 25 articles of 456 were identified. The researches carried out demonstrate that after catheter ablation and Cox Maze operation in patients with atrial fibrillation left atrium volume decrease, atrial contractile function improvment and sinus rhythm restoration are observed. In the absence of AF recurrence and postoperative atrial arrhythmias in early and late postoperative periods in some patients atrial remodeling is expressed. All data were confirmed by echocardiography, computer tomography and magnetic resonance imaging studies both before and after surgery.

  13. Radiofrequency Ablation in Barrett's Esophagus

    Vani J.A. Konda

    2014-01-01

    Full Text Available Radiofrequency ablation (RFA is an endoscopic modality used in the treatment of Barrett's esophagus. RFA may be performed using a balloon-based catheter or using one of the probe catheters that attaches to the distal end of the endoscope. Here we demonstrate step-by-step instruction in using radiofrequency ablation in the treatment of Barrett's esophagus and highlight key concepts in the technique.

  14. Ablative Approaches for Pulmonary Metastases.

    Boyer, Matthew J; Ricardi, Umberto; Ball, David; Salama, Joseph K

    2016-02-01

    Pulmonary metastases are common in patients with cancer for which surgery is considered a standard approach in appropriately selected patients. A number of patients are not candidates for surgery due to a medical comorbidities or the extent of surgery required. For these patients, noninvasive or minimally invasive approaches to ablate pulmonary metastases are potential treatment strategies. This article summarizes the rationale and outcomes for non-surgical treatment approaches, including radiotherapy, radiofrequency and microwave ablation, for pulmonary metastases.

  15. Characterization of Maze Performance in Adrenalectomized Sleep Disrupted Rats: A Comparison of Radial Arm Maze Performance between Adrenalectomized and Sham Adrenalectomized Sleep Disrupted Rats

    2007-01-01

    associated with an increase in orexin , which is also increased by sleep disruption. The Barnes maze does not require food restriction, because the...another behavioral test that detects hippocampal impairments eliminating of food restriction. Food restriction increases corticosterone and orexin

  16. Pulmonary Thermal Ablation: Comparison of Radiofrequency and Microwave Devices by Using Gross Pathologic and CT Findings in a Swine Model

    Brace, Christopher L.; Hinshaw, J. Louis; Laeseke, Paul F.; Sampson, Lisa A.; Lee, Fred T.

    2009-01-01

    Purpose: To compare the performance of equivalently sized radiofrequency and microwave ablation applicators in a normal porcine lung model. Materials and Methods: All experiments were approved by an institutional animal care and use committee. A total of 18 ablations were performed in vivo in normal porcine lungs. By using computed tomographic (CT) fluoroscopic guidance, a 17-gauge cooled triaxial microwave antenna (n = 9) and a 17-gauge cooled radiofrequency (RF) electrode (n = 9) were placed percutaneously. Ablations were performed for 10 minutes by using either 125 W of microwave power or 200 W of RF power delivered with an impedance-based pulsing algorithm. CT images were acquired every minute during ablation to monitor growth. Animals were sacrificed after the procedure. Ablation zones were then excised and sectioned transverse to the applicator in 5-mm increments. Minimum and maximum diameter, cross-sectional area, length, and circularity were measured from gross specimens and CT images. Comparisons of each measurement were performed by using a mixed-effects model; P ablation and mean cross-sectional area (8.25 cm2 ± 0.92 vs 5.45 cm2 ± 1.14, P ablation, compared with RF ablation. With microwave ablation, the zones of ablation were also significantly more circular in cross section (mean circularity, 0.90 ± 0.06 vs 0.82 ± 0.09; P ablation but stabilized without intervention. Conclusion: Microwave ablation with a 17-gauge high-power triaxial antenna creates larger and more circular zones of ablation than does a similarly sized RF applicator in a preclinical animal model. Microwave ablation may be a more effective treatment of lung tumors. © RSNA, 2009 PMID:19336667

  17. Transarterial ablation of hepatocellular carcinoma. Status and developments; Transvaskulaere Ablation des hepatozellulaeren Karzinoms. Ist Chemotherapie alles

    Radeleff, B.A.; Stampfl, U.; Sommer, C.M.; Bellemann, N.; Kauczor, H.U. [Universitaetsklinikum Heidelberg, Abt. Diagnostische und Interventionelle Radiologie, Radiologische Klinik, Heidelberg (Germany); Hoffmann, K. [Universitaetsklinikum Heidelberg, Abt. fuer Allgemein-, Viszeral- und Transplantationschirurgie, Chirurgische Klinik, Heidelberg (Germany); Ganten, T.; Ehehalt, R. [Universitaetsklinikum Heidelberg, Medizinische Klinik IV, Gastroenterologie, Infektionskrankheiten, Vergiftungen, Heidelberg (Germany)

    2012-01-15

    Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and represents the main cause of death among European patients with liver cirrhosis. Only 30-40% of patients diagnosed with HCC are candidates for curative treatment options (e.g. surgical resection, liver transplantation or ablation). The remaining majority of patients must undergo local regional and palliative therapies. Transvascular ablation of HCC takes advantage of the fact that the hypervascularized HCC receives most of its blood supply from the hepatic artery. In this context transvascular ablation describes different therapy regimens which can be assigned to four groups: cTACE (conventional transarterial chemoembolization), bland embolization (transarterial embolization TAE), DEB-TACE (TACE with drug-eluting beads, DEB) and SIRT (selective internal radiation therapy, radioembolization). Conventional TACE is the most common type of transvascular ablation and represents a combination of intra-arterial chemotherapy and embolization with occlusion of the arterial blood supply. However, there is no standardized regimen with respect to the chemotherapeutic drug, the embolic agent, the usage of lipiodol and the interval between the TACE procedures. Even the exact course of a cTACE procedure (order of chemotherapy or embolization) is not standardized. It remains unclear whether or not intra-arterial chemotherapy is definitely required as bland embolization using very small, tightly calibrated spherical particles (without intra-arterial administration of a chemotherapeutic drug) shows tumor necrosis comparable to cTACE. For DEB-TACE microparticles loaded with a chemotherapeutic drug combine the advantages of cTACE and bland embolization. Thereby, a continuing chemotherapeutic effect within the tumor might cause a further increase in intratumoral cytotoxicity and at the same time a decrease in systemic toxicity. (orig.) [German] Das hepatozellulaere Karzinom (HCC) ist weltweit betrachtet das

  18. Image and pathological changes after microwave ablation of breast cancer: A pilot study

    Zhou, Wenbin [Department of Breast Surgery, The First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029 (China); Jiang, Yanni [Department of Radiology, The First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029 (China); Chen, Lin; Ling, Lijun; Liang, Mengdi; Pan, Hong [Department of Breast Surgery, The First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029 (China); Wang, Siqi [Department of Radiology, The First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029 (China); Ding, Qiang [Department of Breast Surgery, The First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029 (China); Liu, Xiaoan, E-mail: liuxiaoan@126.com [Department of Breast Surgery, The First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029 (China); Wang, Shui, E-mail: ws0801@hotmail.com [Department of Breast Surgery, The First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029 (China)

    2014-10-15

    Highlights: • We report successful experience of MWA in breast cancer under local anesthesia. • We report MR imaging evaluation of microwave ablation zone in breast cancer. • Pathological changes after microwave ablation in breast cancer was reported. • 2 min MWA caused an ablation zone with three diameters > 2 cm in breast cancer. - Abstract: Purpose: To prospectively assess MR imaging evaluation of the ablation zone and pathological changes after microwave ablation (MWA) in breast cancer. Materials and methods: Twelve enrolled patients, diagnosed with non-operable locally advanced breast cancer (LABC), were treated by MWA and then neoadjuvant chemotherapy, followed by surgery. MR imaging was applied to evaluate the effect of MWA. Hematoxylin-eosin (HE) staining and transmission electron microscopy (TEM) were applied to analyze the ablated area. Results: All MWA procedures were performed successfully under local anesthesia. For a mean duration of 2.15 min, the mean largest, middle and smallest diameters in the ablated zone 24-h post-ablation in MR imaging were 2.98 cm ± 0.53, 2.51 cm ± 0.41 and 2.23 cm ± 0.41, respectively. The general shape of the ablation zone was close to a sphere. The ablated area became gradually smaller in MR imaging. No adverse effects related to MWA were noted in all 12 patients during and after MWA. HE staining could confirm the effect about 3 months after MWA, which was confirmed by TEM. Conclusions: 2 min MWA can cause an ablation zone with three diameters larger than 2 cm in breast cancer, which may be suitable for the local treatment of breast cancer up to 2 cm in largest diameter. However, the long-term effect of MWA in the treatment of small breast cancer should be determined in the future.

  19. Experience of robotic catheter ablation in humans using a novel remotely steerable catheter sheath

    Wallace, Daniel T.; Goldenberg, Alex S.; Peters, Nicholas S.; Davies, D. Wyn

    2008-01-01

    Background A novel remotely controlled steerable guide catheter has been developed to enable precise manipulation and stable positioning of any eight French (Fr) or smaller electrophysiological catheter within the heart for the purposes of mapping and ablation. Objective To report our initial experience using this system for remotely performing catheter ablation in humans. Methods Consecutive patients attending for routine ablation were recruited. Various conventional diagnostic catheters were inserted through the left femoral vein in preparation for treating an accessory pathway (n = 1), atrial flutter (n = 2) and atrial fibrillation (n = 7). The steerable guide catheter was inserted into the right femoral vein through which various irrigated and non-irrigated tip ablation catheters were used. Conventional endpoints of loss of pathway conduction, bidirectional cavotricuspid isthmus block and four pulmonary vein isolation were used to determine acute procedural success. Results Ten patients underwent remote catheter ablation using conventional and/or 3D non-fluoroscopic mapping technologies. All procedural endpoints were achieved using the robotic control system without manual manipulation of the ablation catheter. There was no major complication. A radiation dosimeter positioned next to the operator 2.7 m away from the X-ray source showed negligible exposure despite a mean cumulative dose area product of 7,281.4 cGycm2 for all ten ablation procedures. Conclusions Safe and clinically effective remote navigation of ablation catheters can be achieved using a novel remotely controlled steerable guide catheter in a variety of arrhythmias. The system is compatible with current mapping and ablation technologies Remote navigation substantially reduces radiation exposure to the operator. Electronic supplementary material The online version of this article (doi:10.1007/s10840-007-9184-z) contains supplementary material, which is available to authorized users

  20. Percutaneous radiofrequency ablation for lung tumors beneath the rib under CT fluoroscopic guidance with gantry tilt

    Suzuki, Takanobu; Yamagami, Takuji; Tanaka, Osamu; Yoshimatsu, Rika; Miura, Hiroshi; Nishimura, Tsunehiko (Dept. of Radiology, Graduate School of Medical Science, Kyoto Prefectural Univ. of Medicine, Kamigyo, Kyoto (Japan)), e-mail: yamagami@koto.kpu-m.ac.jp

    2010-05-15

    Background: Radiofrequency (RF) ablation of lung tumors has become a treatment of choice, especially for unresectable cases. However, RF ablation of small lung lesions located just beneath the rib is difficult. Purpose: To evaluate the efficacy and safety of gantry tilting for the performance of RF ablation of peripheral lesions located beneath the rib. Material and Methods: Our study was based on 18 of 293 lesions in the lung for which RF ablation was performed under CT scan fluoroscopic guidance at our institution between October 2004 and March 2009. For these 18 lesions, RF ablation was performed with gantry tilting because a rib blocked visualization of the RF ablation route even after other attempts had been made to change the relationship between the target and the rib. Results: All RF needles, with only one exception, were successfully advanced to hit the tumor. The commonest complication was a pneumothorax, which occurred in seven procedures. No serious complications occurred. The progression-free rates were 82.4% at 6 months, 62.5% at 12 months, and 30% at 24 months. Mean local progression-free duration was 17.6+-11.6 months (range 4-36 months). Conclusion: RF ablation under CT scan fluoroscopic guidance with gantry tilt is a useful and safe technique for RF ablation of lung nodules located beneath the rib

  1. Una técnica para la extirpación de los órganos vomeronasales en el armadillo Chaetophractus villosus. Abordaje desde la cavidad bucal - A surgical procedure for the ablation of the Vomeronasal Organs in the armadillo Chaetophractus villosus. Approach from oral cavity

    Iodice, O. H.

    2010-03-01

    Full Text Available ResumenSe describen los pasos de un procedimiento quirúrgico para la extirpación bilateral de los órganos vomeronasales del armadillo Chaetophractus villosus (Mammalia, Xenarthra. Cada órgano está ubicado en el piso de la cavidad nasal, adosado a cada lado del tabique nasal. Los órganos se abordan a través de unaabertura practicada en el techo de la cavidad bucal. Este procedimiento se realiza bajo lupa estereoscópica y permite una visualización directa de los órganos Los mismos se destruyen por medio de una fresa accionada por un torno. De este modo se tiene la certeza de una ablación total. La posterior verificación por mediode cortes histológicos no es por lo tanto necesaria. Esto representa una ventaja importante puesto que las características físicas del hueso de estos animales requieren períodos largos de ablandamiento (generalmente alrededor tres meses. SummaryA surgical procedure for the bilateral ablation of the vomeronasal organs of the armadillo Chaetophractus villosus (Mammalia, Xenarthra is described. The organs are approached from the roof of the oral cavity through a longitudinal slit performed with a dental drill. This procedure is performed under magnifying stereoscopic lens and permits the direct visualization of the organs. Those structures are then destroyed with the dental drill. This provides certainty of totalablation. As a consequence, verification by means of histological sections is not needed. This represents an important advantage since the physical characteristics of the bone of these animals require long periods of softening (usually around three months.

  2. Case Experience of Radiofrequency Ablation for Benign Thyroid Nodules: From an Ex Vivo Animal Study to an Initial Ablation in Taiwan

    Ming-Tsang Lee

    2016-03-01

    Full Text Available Radiofrequency ablation (RFA is a minimally invasive technique, used with ultrasound or computed tomography guidance, which can produce tissue coagulation necrosis in various kinds of tumors in the human body. In the past 10 years, numerous studies about RFA in benign thyroid nodules have been published. Reviewing these studies, we noticed that the effectiveness of ablation was higher when it was performed with the “moving-shot technique” via an internally cooled electrode. A consensus statement published from the Korean Society of Radiology also suggested the moving-shot technique as a standard ablation procedure for benign thyroid nodule ablation in Korea. In Taiwan, most symptomatic benign nodules are currently treated with surgical removal. RFA for mass lesions is primarily performed for the treatment of metastatic hepatic tumors. In our case, we have attempted to introduce RFA for benign thyroid nodules in Taiwan. Because endocrinologists in Taiwan were not familiar with this technique, we adopted a stepwise approach in learning how to perform RFA. We conducted ex vivo animal ablation exercises to gain experience in setting the radiofrequency generator for the right ablation mode and appropriate power output. The thyroid nodule volume reduction rate after 1 year of follow up was approximately 50% in this case. The most important thing we learned from this trial is that we confirmed the safety of thyroid nodule ablation. To the best of our knowledge, this is the first reported study of RFA of a thyroid nodule in Taiwan.

  3. Training for advanced endoscopic procedures.

    Feurer, Matthew E; Draganov, Peter V

    2016-06-01

    Advanced endoscopy has evolved from diagnostic ERCP to an ever-increasing array of therapeutic procedures including EUS with FNA, ablative therapies, deep enteroscopy, luminal stenting, endoscopic suturing and endoscopic mucosal resection among others. As these procedures have become increasingly more complex, the risk of potential complications has also risen. Training in advanced endoscopy involves more than obtaining a minimum number of therapeutic procedures. The means of assessing a trainee's competence level and ability to practice independently continues to be a matter of debate. The use of quality indicators to measure performance levels may be beneficial as more advanced techniques and procedures become available.

  4. Impact of different ablation strategies on the delayed cure after trans-catheter ablation for treating patients with atrial fibrillation

    DONG Jian-zeng; MA Chang-sheng; LIU Xing-peng; LONG De-yong; LIU Xiao-qing; WANG Jing; Fang Dong-ping; HAO Peng; LI Yong-sheng; LIU Chuang

    2005-01-01

    Background Delayed cure had been observed in recurrent cases after index ablation of atrial fibrillation (AF), however, its mechanism and incidence have not been elucidated in detail. This study aims to investigate the impact of different ablation strategies on the incidence of delayed cure and its possible mechanisms after trans-catheter ablation of AF. Methods One hundred and fifty-one consecutive cases with highly symptomatic, drug refractory AF were included in this study [M/F=109/42, mean age (56.0±11.2) (18-79) years]. Segmental pulmonary vein ablation (SPVA) was performed in 83 patients with the guidance of circular mapping catheter (SPVA Group), circumferential PV linear ablation (CPVA) was carried out in the rest 68 cases under the guidance of 3 dimensional mapping system in conjunction with circular mapping catheter (CPVA Group). Delayed cure was defined as that early recurrence of atrial tachyarrhythmias (AF, atrial tachycardia, or atrial flutter) after ablation procedure was no longer observed during subsequent follow-up, and stable sinus rhythm was maintained ≥2 months. Results Early recurrence of atrial tachyarrhythmias was detected in 41 cases from SPVA group and 23 cases from CPVA group, and delayed cure occurred in 21.9% (9/41) of the cases from SPVA group and 47.8% (11/23) of the cases from CPVA group, more delayed cure in later group was observed (P<0.05). Meanwhile, patients in SPVA group took a longer time to achieve a delayed cure [(27.0±18.0) days vs (14.0±8.1) days, P<0.05], and presented more recurrent episodes [(3.50±1.08) times a week vs (2.42±1.11) times a week, P<0.05]. However, recurrent episodes after index ablation were markedly decreased in cases with delayed cure from both groups (P<0.05). Conclusions Despite of an early recurrence of atrial tachyarrhythimas after index ablation of AF, delayed cure occurs in a significant number of patients undergoing either SPVA or CPVA. However, different ablation strategies place

  5. Esophageal papilloma: Flexible endoscopic ablation byradiofrequency

    Gianmattia del Genio; Federica del Genio; Pietro Schettino; Paolo Limongelli; Salvatore Tolone; Luigi Brusciano; Manuela Avellino; Chiara Vitiello; Giovanni Docimo; Angelo Pezzullo; Ludovico Docimo

    2015-01-01

    Squamous papilloma of the esophagus is a rare benignlesion of the esophagus. Radiofrequency ablation is anestablished endoscopic technique for the eradication ofBarrett esophagus. No cases of endoscopic ablation ofesophageal papilloma by radiofrequency ablation (RFA)have been reported. We report a case of esophagealpapilloma successfully treated with a single sessionof radiofrequency ablation. Endoscopic ablation ofthe lesion was achieved by radiofrequency using anew catheter inserted through the working channelof endoscope. The esophageal ablated tissue wasremoved by a specifically designed cup. Completeablation was confirmed at 3 mo by endoscopy withbiopsies. This case supports feasibility and safety of asa new potential indication for BarrxTM RFA in patientswith esophageal papilloma.

  6. Endoscopic management of an esophagopericardial fistula after radiofrequency ablation for atrial fibrillation.

    Quénéhervé, Lucille; Musquer, Nicolas; Léauté, Franck; Coron, Emmanuel

    2013-06-07

    A case is reported of a 76-year-old man with a past history of atrial fibrillation. A radiofrequency ablation procedure was suggested following several failed cardioversion attempts. However, an esophagopericardial fistula complicated the procedure. This life-threatening complication was successfully managed using both the placement of a covered esophageal stent and surgical pericardial and mediastinal drainage. In fact, no persisting fistula could be detected when the esophageal stent was removed seven weeks later. Atrioesophageal and esophagopericardial fistulas are two of the most severe complications associated with cardiological radiofrequency ablation procedures. They are responsible for majority of the deaths associated with this procedure. Despite the extremely high morbimortality associated with cardiothoracic surgery in such conditions, this treatment is the gold-standard for the management of such complications. This case report emphasizes the importance and efficacy of the endoscopic approach as part of a multidisciplinary management approach to this serious adverse event following radiofrequency ablation for atrial fibrillation.

  7. Multimodality imaging to guide cardiac interventional procedures

    Tops, Laurens Franciscus

    2010-01-01

    In recent years, a number of new cardiac interventional procedures have been introduced. Catheter ablation procedures for atrial fibrillation (AF) have been refined and are now considered a good treatment option in patients with drug-refractory AF. In cardiac pacing, cardiac resynchronization therap

  8. Femtosecond laser ablation of enamel

    Le, Quang-Tri; Bertrand, Caroline; Vilar, Rui

    2016-06-01

    The surface topographical, compositional, and structural modifications induced in human enamel by femtosecond laser ablation is studied. The laser treatments were performed using a Yb:KYW chirped-pulse-regenerative amplification laser system (560 fs and 1030 nm) and fluences up to 14 J/cm2. The ablation surfaces were studied by scanning electron microscopy, grazing incidence x-ray diffraction, and micro-Raman spectroscopy. Regardless of the fluence, the ablation surfaces were covered by a layer of resolidified material, indicating that ablation is accompanied by melting of hydroxyapatite. This layer presented pores and exploded gas bubbles, created by the release of gaseous decomposition products of hydroxyapatite (CO2 and H2O) within the liquid phase. In the specimen treated with 1-kHz repetition frequency and 14 J/cm2, thickness of the resolidified material is in the range of 300 to 900 nm. The micro-Raman analysis revealed that the resolidified material contains amorphous calcium phosphate, while grazing incidence x-ray diffraction analysis allowed detecting traces of a calcium phosphate other than hydroxyapatite, probably β-tricalcium phosphate Ca3), at the surface of this specimen. The present results show that the ablation of enamel involves melting of enamel's hydroxyapatite, but the thickness of the altered layer is very small and thermal damage of the remaining material is negligible.

  9. Catheter ablation of atrial fibrillation in patients with severely impaired left ventricular systolic function.

    Kato, Ken; Ejima, Koichiro; Fukushima, Noritoshi; Ishizawa, Makoto; Wakisaka, Osamu; Henmi, Ryuta; Yoshida, Kentaro; Nuki, Toshiaki; Arai, Kotaro; Yashiro, Bun; Manaka, Tetsuyuki; Ashihara, Kyomi; Shoda, Morio; Hagiwara, Nobuhisa

    2016-04-01

    Little is known about the outcome of catheter ablation of atrial fibrillation (AF) in patients with heart failure (HF) and a severely reduced left ventricular ejection fraction (LVEF). We aimed to clarify the effectiveness of catheter ablation of AF in patients with a severely low LVEF. This retrospective study included 18 consecutive patients with HF and an LVEF of ≤ 35 % who underwent catheter ablation of AF. We investigated the clinical parameters, echocardiographic parameters and the incidence of hospitalizations for HF. During a median follow-up of 21 months (IQR, 13-40) after the final procedure (9 with repeat procedures), 11 patients (61 %) maintained sinus rhythm (SR) (6 with amiodarone). The LVEF and NYHA class significantly improved at 6 months after the CA in 12 patients (67 %) who were in SR or had recurrent paroxysmal AF (from 25.8 ± 6.3 to 37.0 ± 11.7 %, P = 0.02, and from 2.3 ± 0.5 to 1.5 ± 0.7, P < 0.01, respectively) but not in patients who experienced recurrent persistent AF. The patients with SR or recurrent paroxysmal AF had significantly fewer hospitalizations for HF than those with recurrent persistent AF after the AF ablation (log-rank test; P < 0.01). Catheter ablation of AF improved the clinical status in patients with an LVEF of ≤ 35 %. A repeat ablation procedure and amiodarone were often necessary to obtain a favorable outcome.

  10. Percutaneous Ablation for Small Renal Masses—Complications

    Kurup, A. Nicholas

    2014-01-01

    Although percutaneous ablation of small renal masses is generally safe, interventional radiologists should be aware of the various complications that may arise from the procedure. Renal hemorrhage is the most common significant complication. Additional less common but serious complications include injury to or stenosis of the ureter or ureteropelvic junction, infection/abscess, sensory or motor nerve injury, pneumothorax, needle tract seeding, and skin burn. Most complications may be treated ...

  11. Surgical and Pathological Changes after Radiofrequency Ablation of Thyroid Nodules

    Chiara Dobrinja; Stella Bernardi; Bruno Fabris; Rita Eramo; Petra Makovac; Gabriele Bazzocchi; Lanfranco Piscopello; Enrica Barro; Nicolò de Manzini; Deborah Bonazza; Maurizio Pinamonti; Fabrizio Zanconati; Fulvio Stacul

    2015-01-01

    Background. Radiofrequency ablation (RFA) has been recently advocated as an effective technique for the treatment of symptomatic benign thyroid nodules. It is not known to what extent it may affect any subsequent thyroid surgery and/or histological diagnosis. Materials and Methods. RFA was performed on 64 symptomatic Thy2 nodules (benign nodules) and 6 symptomatic Thy3 nodules (follicular lesions/follicular neoplasms). Two Thy3 nodules regrew after the procedure, and these patients accepted t...

  12. Efficacy and Safety of Atrial Fibrillation Ablation Using Remote Magnetic Navigation

    Jin, Q I; Pehrson, Steen; Jacobsen, Peter Karl;

    2016-01-01

    , respectively. The mean fluoroscopy time was 5.4 ± 3.7 minutes. Compared to PAF patients, procedural time and ablation time were significantly increased in patients with PerAF by 10% (P 5.3 ± 3.5 minutes, PAF vs. 5.6 ± 4......BACKGROUND: The objective of this study was to assess the procedural outcomes of catheter ablation guided by remote magnetic navigation (RMN) in a large cohort of patients with paroxysmal trial fibrillation (PAF) and persistent AF (PerAF). METHODS: A total of 726 patients (547 male, age: 58.5 ± 10...... and six ablation procedures were analyzed. One-third of the patients (240/726) were ablated on more than one occasion, resulting in a mean of 1.3 ± 0.6 times for the entire group. When analyzing all procedures, the mean procedural time and ablation time was 134 ± 35 minutes and 2,130 ± 1,025 seconds...

  13. LAPAROSCOPIC NEPHRECTOMY USING RADIOFREQUENCY THERMAL ABLATION

    B. Ya. Alekseev

    2012-01-01

    Full Text Available The wide use of current diagnostic techniques, such as ultrasound study, computed tomography, and magnetic resonance imaging, has led to significantly increased detection rates for disease in its early stages. This gave rise to a change in the standards for the treatment of locally advanced renal cell carcinoma (RCC. Laparoscopic nephrectomy (LN has recently become the standard treatment of locally advanced RCC in the clinics having much experience with laparoscopic surgery. The chief drawback of LN is difficulties in maintaining intraoperative hemostasis and a need for creating renal tissue ischemia. The paper gives the intermediate results of application of the new procedure of LN using radiofrequency thermal ablation in patients with non-ischemic early-stage RCC.

  14. Radiofrequency ablation of a misdiagnosed Brodie's abscess.

    Chan, Rs; Abdullah, Bjj; Aik, S; Tok, Ch

    2011-04-01

    Radiofrequency ablation (RFA) therapy is recognised as a safe and effective treatment option for osteoid osteoma. This case report describes a 27-year-old man who underwent computed tomography (CT)-guided percutaneous RFA for a femoral osteoid osteoma, which was diagnosed based on his clinical presentation and CT findings. The patient developed worsening symptoms complicated by osteomyelitis after the procedure. His clinical progression and subsequent MRI findings had led to a revised diagnosis of a Brodie's abscess, which was further supported by the eventual resolution of his symptoms following a combination of antibiotics treatment and surgical irrigations. This case report illustrates the unusual MRI features of osteomyelitis mimicking soft tissue tumours following RFA of a misdiagnosed Brodie's abscess and highlights the importance of a confirmatory histopathological diagnosis for an osteoid osteoma prior to treatment.

  15. Intracardiac Echocardiography during Catheter-Based Ablation of Atrial Fibrillation

    Jürgen Biermann

    2012-01-01

    Full Text Available Accurate delineation of the variable left atrial anatomy is of utmost importance during anatomically based ablation procedures for atrial fibrillation targeting the pulmonary veins and possibly other structures of the atria. Intracardiac echocardiography allows real-time visualisation of the left atrium and adjacent structures and thus facilitates precise guidance of catheter-based ablation of atrial fibrillation. In patients with abnormal anatomy of the atria and/or the interatrial septum, intracardiac ultrasound might be especially valuable to guide transseptal access. Software algorithms like CARTOSound (Biosense Webster, Diamond Bar, USA offer the opportunity to reconstruct multiple two-dimensional ultrasound fans generated by intracardiac echocardiography to a three-dimensional object which can be merged to a computed tomography or magnetic resonance imaging reconstruction of the left atrium. Intracardiac ultrasound reduces dwell time of catheters in the left atrium, fluoroscopy, and procedural time and is invaluable concerning early identification of potential adverse events. The application of intracardiac echocardiography has the great capability to improve success rates of catheter-based ablation procedures.

  16. A cold radial maze for long-lasting spatial memory in mice.

    Vizi, Sándor; Mansuy, Isabelle M

    2013-03-15

    Here we report the establishment of a novel spatial learning and memory test called the cold radial maze. It is specifically designed for mice, with all conditions tailored to their natural behaviors. The cold radial maze is a dry-land test with easy-to-measure variables that relies on a consistent motivation system and limits the moderately adverse experience to the duration of testing. Training on this maze produces a long-lasting, resistant, and reversible spatial memory in mice in a reproducible way, without introducing undesirable side effects typically produced in other spatial learning tests. This novel behavioral technique may prove useful in studying mouse models of memory impairment-associated human conditions.

  17. Microwave ablation of hepatocellular carcinoma

    2015-01-01

    Although surgical resection is still the optimal treatmentoption for early-stage hepatocellular carcinoma(HCC) in patients with well compensated cirrhosis,thermal ablation techniques provide a valid nonsurgicaltreatment alternative, thanks to their minimalinvasiveness, excellent tolerability and safety profile,proven efficacy in local disease control, virtuallyunlimited repeatability and cost-effectiveness. Differentenergy sources are currently employed in clinics asphysical agents for percutaneous or intra-surgicalthermal ablation of HCC nodules. Among them, radiofrequency(RF) currents are the most used, whilemicrowave ablations (MWA) are becoming increasinglypopular. Starting from the 90s', RF ablation (RFA) rapidlybecame the standard of care in ablation, especially inthe treatment of small HCC nodules; however, RFAexhibits substantial performance limitations in thetreatment of large lesions and/or tumors located nearmajor heat sinks. MWA, first introduced in the FarEastern clinical practice in the 80s', showing promisingresults but also severe limitations in the controllabilityof the emitted field and in the high amount of poweremployed for the ablation of large tumors, resultingin a poor coagulative performance and a relativelyhigh complication rate, nowadays shows better resultsboth in terms of treatment controllability and of overallcoagulative performance, thanks to the improvementof technology. In this review we provide an extensiveand detailed overview of the key physical and technicalaspects of MWA and of the currently available systems,and we want to discuss the most relevant published dataon MWA treatments of HCC nodules in regard to clinicalresults and to the type and rate of complications, both inabsolute terms and in comparison with RFA.

  18. Effects of rolipram and zaprinast on learning and memory in the Morris water maze and radial arm maze tests in naive mice.

    Akar, F; Mutlu, O; Celikyurt, I K; Ulak, G; Erden, F; Bektas, E; Tanyeri, P

    2015-02-01

    Inhibition of phosphodiesterase 5 (PDE) improved recognition memory and counteracted spatial learning impairment induced by nitric oxide synthase (NOS) inhibition in recent studies. Aim of this study was to investigate effects of rolipram, a PDE4 inhibitor and zaprinast, a PDE5 inhibitor, on learning and memory in Morris water maze (MWM) and radial arm maze (RAM) tests in naive mice. Male Balb-c mice were treated subchronically with zaprinast (3 and 10 mg/kg) and rolipram (0.05 and 0.1 mg/kg) for 6 days in the MWM test and acutely before the retention trial of radial arm maze test. Rolipram (0.05 and 0.1 mg/kg) significantly decreased escape latency between 2(nd) and 5(th) sessions, while zaprinast (10 mg/kg) significantly decreased escape latency only in 2(nd) session. Rolipram (0.05 and 0.1 mg/kg) and zaprinast (10 mg/kg) significantly increased time spent in escape platform's quadrant in probe trial of MWM test; only rolipram decreased mean distance to platform, while zaprinast had no effect on mean distance to platform. Zaprinast (3 and 10 mg/kg) significantly decreased number of errors compared to control group, while rolipram (0.05 and 0.1mg/kg) had no effect on number of errors in retention trial of RAM test. Rolipram (0.05 and 0.1 mg/kg) and zaprinast (10 mg/kg) significantly decreased time spent to complete retention trial (latency) compared to control group. Our study revealed that both zaprinast and rolipram enhanced spatial memory in MWM, while zaprinast seems to have more memory enhancing effects compared to rolipram in radial arm maze test.

  19. Radiofrequency ablation of liver metastases; Radiofrequenzablation von Lebermetastasen

    Pereira, P.L.; Clasen, S.; Schmidt, D.; Wiskirchen, J.; Tepe, G.; Claussen, C.D. [Abt. fuer Radiologische Diagnostik, Eberhard-Karls-Univ. Tuebingen (Germany); Boss, A. [Abt. fuer Radiologische Diagnostik, Eberhard-Karls-Univ. Tuebingen (Germany); Sektion fuer Experimentelle Radiologie der Abt. fuer Radiologische Diagnostik, Eberhard-Karls-Univ. Tuebingen (Germany); Gouttefangeas, C. [Abt. Immunologie des Inst. fuer Zellbiologie, Eberhard-Karls-Univ. Tuebingen (Germany); Burkart, C. [Zentrum fuer gastroenterologische Onkologie der Medizinischen Klinik, Eberhard-Karls-Univ. Tuebingen (Germany)

    2004-04-01

    The liver is the second only to lymph nodes as the most common site of metastatic disease irrespective of the primary tumor. Up to 50% of all patients with malignant diseases will develop liver metastases with a significant morbidity and mortality. Although the surgical resection leads to an improvement of the survival time, only approximately 20% of the patients are eligible for surgical intervention. Radiofrequency (RF) ablation represents one of the most important alternatives as well as complementary methods for the therapy of liver metastases. RF ablation can lead in a selected patient group to a palliation or to an increased life expectancy. RF ablation appears either safer (vs. cryotherapy) or easier (vs. laser) or more effective (percutaneous ethanol instillation [PEI]), transarterial chemoembolisation [TACE] in comparison with other minimal invasive procedures. RF ablation can be performed percutaneously, laparoscopically or intraoperatively and may be combined with chemotherapy as well as with surgical resection. Permanent technical improvements of RF systems, a better understanding of the underlying electrophysiological principles and an interdisciplinary approach will lead to a prognosis improvement in patients with liver metastases. (orig.) [German] Die Leber ist unabhaengig vom Primaertumor nach den Lymphknoten die zweithaeufigste Lokalisation von Metastasen. Bis zu 50% aller Patienten mit malignen Erkrankungen werden im Verlauf ihrer Erkrankung Lebermetastasen entwickeln, die mit einer signifikanten Morbiditaet und Mortalitaet verbunden sind. Obwohl die chirurgische Resektion zu einer verlaengerten Ueberlebenszeit fuehrt, sind nur ca. 20% der Patienten fuer einen chirurgischen Eingriff geeignet. Die Radiofrequenz-(RF-)Ablation stellt derzeit eine der effektivsten Alternativen und komplementaeren Methoden bei der Therapie von Lebermetastasen dar. In einem selektierten Patientengut fuehrt die RF-Ablation ueber den palliativen Einsatz hinaus zu einer

  20. Laser ablation at the hydrodynamic regime

    Gojani Ardian B.

    2013-04-01

    Full Text Available Laser ablation of several metals and PVC polymer by high energy nanosecond laser pulses is investigated experimentaly. Visualization by shadowgraphy revealed the dynamics of the discontinuities in ambient air and ablation plume above the target surface, while surface profiling allowed for determination of the ablated mass.

  1. Laser ablation at the hydrodynamic regime

    Gojani Ardian B.

    2013-01-01

    Laser ablation of several metals and PVC polymer by high energy nanosecond laser pulses is investigated experimentaly. Visualization by shadowgraphy revealed the dynamics of the discontinuities in ambient air and ablation plume above the target surface, while surface profiling allowed for determination of the ablated mass.

  2. Laser ablation and optical surface damage

    Chase, L. L.; Hamza, A. V.; Lee, H. W. H.

    Laser ablation usually accompanies optical surface damage to bare surfaces and coatings. Investigations of optical damage mechanisms by observation of ablation processes at laser fluences very close to the optical damage threshold are described. Several promising surface characterization methods for investigating damage mechanisms are also described. The possible role of laser ablation in initiating or promoting optical surface damage is discussed.

  3. Laser ablation mechanisms and optical surface damage

    Chase, L. L.; Hamza, A. V.; Lee, H. W. H.

    1991-05-01

    Laser ablation usually accompanies optical surface damage to bare surfaces and coatings. Investigations of optical damage mechanisms by observation of ablation processes at laser fluences very close to the optical damage threshold are described. Several promising surface characterization methods for investigating damage mechanisms are also described. The possible role of laser ablation in initiating or promoting optical surface damage is discussed.

  4. Soft thrombus formation in radiofrequency catheter ablation

    Demolin, JM; Eick, OJ; Munch, K; Koullick, E; Nakagawa, H; Wittkampf, FHM

    2002-01-01

    During RF catheter ablation, local temperature elevation can result in coagulum formation on the ablation electrode, resulting in impedance rise. A recent study has also demonstrated the formation of a so-called soft thrombus during experimental ablations. This deposit poorly adhered to the catheter

  5. Catheter ablation of parahisian premature ventricular complex.

    Kim, Jun; Kim, Jeong Su; Park, Yong Hyun; Kim, June Hong; Chun, Kook Jin

    2011-12-01

    Catheter ablation is performed in selected patients with a symptomatic premature ventricular complex (PVC) or PVC-induced cardiomyopathy. Ablation of PVC from the His region has a high risk of inducing a complete atrioventricular block. Here we report successful catheter ablation of a parahisian PVC in a 63-year-old man.

  6. Ablation of Solid Hydrogen in a Plasma

    Jørgensen, L. W.; Sillesen, Alfred Hegaard

    1979-01-01

    Several hydrogen pellet ablation models based on the formation of a shielding neutral cloud have been reported by different authors. The predicted ablation rates are shown to follow almost the same scaling law and this is used to explain the authors' ablation experiment....

  7. Regional pericarditis status post cardiac ablation: A case report

    Joseph Orme

    2014-01-01

    Full Text Available Context: Regional pericarditis is elusive and difficult to diagnosis. Healthcare providers should be familiar with post-cardiac ablation complications as this procedure is now widespread and frequently performed. The management of regional pericarditis differs greatly from that of acute myocardial infarction. Case report: A 52 year-old male underwent atrial fibrillation ablation and developed severe mid-sternal chest pain the following day with electrocardiographic findings suggestive of acute myocardial infarction, and underwent coronary angiography, a left ventriculogram, and 2D transthoracic echocardiogram, all of which were unremarkable without evidence of obstructive coronary disease, wall motion abnormalities, or pericardial effusions. Ultimately, the patient was diagnosed with regional pericarditis. After diagnosis, the patient′s presenting symptoms resolved with treatment including nonsteroidal anti-inflammatory agents and colchicine. Conclusion: This is the first reported case study of regional pericarditis status post cardiac ablation. Electrocardiographic findings were classic for an acute myocardial infarction; however, coronary angiography and left ventriculogram demonstrated no acute coronary occlusion or ventricular wall motion abnormalities. Healthcare professionals must remember that the electrocardiographic findings in pericarditis are not always classic and that pericarditis can occur status post cardiac ablation.

  8. Simulation of intracardiac electrograms around acute ablation lesions

    Greiner Joachim

    2016-09-01

    Full Text Available Radiofrequency ablation (RFA is a widely used clinical treatment for many types of cardiac arrhythmias. However, nontransmural lesions and gaps between linear lesions often lead to recurrence of the arrhythmia. Intracardiac electrograms (IEGMs provide real-time information regarding the state of the cardiac tissue surrounding the catheter tip. Nevertheless, the formation and interpretation of IEGMs during the RFA procedure is complex and yet not fully understood. In this in-silico study, we propose a computational model for acute ablation lesions. Our model consists of a necrotic scar core and a border zone, describing irreversible and reversible temperature induced electrophysiological phenomena. These phenomena are modeled by varying the intra- and extracellular conductivity of the tissue as well as a regulating zone factor. The computational model is evaluated regarding its feasibility and validity. Therefore, this model was compared to an existing one and to clinical measurements of five patients undergoing RFA. The results show that the model can indeed be used to recreate IEGMs. We computed IEGMs arising from complex ablation scars, such as scars with gaps or two overlapping ellipsoid scars. For orthogonal catheter orientation, the presence of a second necrotic core in the near-field of a punctiform acute ablation lesion had minor impact on the resulting signal morphology. The presented model can serve as a base for further research on the formation and interpretation of IEGMs.

  9. Robotic-assisted thermal ablation of liver tumours

    Abdullah, Basri Johan Jeet; Yeong, Chai Hong [University of Malaya, Department of Biomedical Imaging and University of Malaya Research Imaging Centre, Faculty of Medicine, Kuala Lumpur (Malaysia); University of Malaya, Department of Internal Medicine, Faculty of Medicine, Kuala Lumpur (Malaysia); Goh, Khean Lee [University of Malaya, Department of Internal Medicine, Faculty of Medicine, Kuala Lumpur (Malaysia); Yoong, Boon Koon [University of Malaya, Department of Surgery, Faculty of Medicine, Kuala Lumpur (Malaysia); Ho, Gwo Fuang [University of Malaya, Department of Oncology, Faculty of Medicine, Kuala Lumpur (Malaysia); Yim, Carolyn Chue Wai [University of Malaya, Department of Anesthesia, Faculty of Medicine, Kuala Lumpur (Malaysia); Kulkarni, Anjali [Perfint Healthcare Corporation, Florence, OR (United States)

    2015-01-15

    This study aimed to assess the technical success, radiation dose, safety and performance level of liver thermal ablation using a computed tomography (CT)-guided robotic positioning system. Radiofrequency and microwave ablation of liver tumours were performed on 20 patients (40 lesions) with the assistance of a CT-guided robotic positioning system. The accuracy of probe placement, number of readjustments and total radiation dose to each patient were recorded. The performance level was evaluated on a five-point scale (5-1: excellent-poor). The radiation doses were compared against 30 patients with 48 lesions (control) treated without robotic assistance. Thermal ablation was successfully completed in 20 patients with 40 lesions and confirmed on multiphasic contrast-enhanced CT. No procedure related complications were noted in this study. The average number of needle readjustment was 0.8 ± 0.8. The total CT dose (DLP) for the entire robotic assisted thermal ablation was 1382 ± 536 mGy.cm, while the CT fluoroscopic dose (DLP) per lesion was 352 ± 228 mGy.cm. There was no statistically significant (p > 0.05) dose reduction found between the robotic-assisted versus the conventional method. This study revealed that robotic-assisted planning and needle placement appears to be safe, with high accuracy and a comparable radiation dose to patients. (orig.)

  10. Nanosecond laser ablation of bulk Al, Bronze, and Cu: ablation rate saturation and laserinduced oxidation

    R. Maisterrena-Epstein; S. Camacho-López; L. Escobar-Alarcón; M. A. Camacho-López

    2007-01-01

    In this work we report about the characteristics of nanosecond laser ablation, in atmospheric air, of bulk Al, Bronze, and Cu. Average per pulse laser ablation rate and its dependence on ablation depth is presented for these three metals. We will demonstrate and discuss some distinctive features of the ablation saturation effect of the above metals. We will also present results on laser-induced oxidation of the metals which results off the ablation event. We studied the laser-induced oxidatio...

  11. Does Radio Frequency Ablation (RFA) Epiphysiodesis Affect Joint Cartilage?

    Shiguetomi Medina, Juan Manuel; Abood, Ahmed Abdul-Hussein; Rahbek, Ole;

    Background: Epiphysiodesis made with RFA has resulted, in animal models, an effective procedure that disrupts the growth plate and induces LLD. This procedure involves an increase of temperature (>92°C) of the targeted region causing thermal damage. To our knowledge, no study that investigates...... the effect of this procedure in the adjacent joint articular cartilage has been reported Purpose / Aim of Study: Proof of concept that epiphysiodesis made with RFA is a safe procedure that disrupts the growth plate without damaging the adjacent joint articular cartilage Materials and Methods: RFA...... articular joint cartilage. This study resembles possible results of RFA epiphysiodesis on humans. Previous studies suggest that an 8 min ablation is enough to disrupt the growth plate. This study shows that RFA can be done safely in the growing physis even on triple-long procedures. It is important...

  12. Factors Associated with Recurrence of Varicose Veins after Thermal Ablation: Results of The Recurrent Veins after Thermal Ablation Study

    R. G. Bush

    2014-01-01

    Full Text Available Background. The goal of this retrospective cohort study (REVATA was to determine the site, source, and contributory factors of varicose vein recurrence after radiofrequency (RF and laser ablation. Methods. Seven centers enrolled patients into the study over a 1-year period. All patients underwent previous thermal ablation of the great saphenous vein (GSV, small saphenous vein (SSV, or anterior accessory great saphenous vein (AAGSV. From a specific designed study tool, the etiology of recurrence was identified. Results. 2,380 patients were evaluated during this time frame. A total of 164 patients had varicose vein recurrence at a median of 3 years. GSV ablation was the initial treatment in 159 patients (RF: 33, laser: 126, 52 of these patients had either SSV or AAGSV ablation concurrently. Total or partial GSV recanalization occurred in 47 patients. New AAGSV reflux occurred in 40 patients, and new SSV reflux occurred in 24 patients. Perforator pathology was present in 64% of patients. Conclusion. Recurrence of varicose veins occurred at a median of 3 years after procedure. The four most important factors associated with recurrent veins included perforating veins, recanalized GSV, new AAGSV reflux, and new SSV reflux in decreasing frequency. Patients who underwent RF treatment had a statistically higher rate of recanalization than those treated with laser.

  13. Photochemical Ablation of Organic Solids

    Garrison, Barbara

    2004-03-01

    As discovered by Srinivasan in 1982, irradiation of materials by far UV laser light can lead to photochemical ablation, a process distinct from normal thermal ablation in which the laser primarily heats the material. A versatile mesoscopic model for molecular dynamics simulations of the laser ablation phenomena is presented. The model incorporates both the thermal and photochemical events, that is, both heating of the system and UV induced bond-cleavage followed by abstraction and radical-radical recombination reactions. The results from the simulations are compared to experimental data and the basic physics and chemistry for each irradiation regime are discussed. Initial results from polymer ablation simulations will be presented. L. V. Zhigilei, P. B. S. Kodali and B. J. Garrison, J. Phys. Chem. B, 102, 2845-2853 (1998); L. V. Zhigilei and B. J. Garrison, Journal of Applied Physics, 88, 1281-1298 (2000). Y. G. Yingling, L. V. Zhigilei and B. J. Garrison, J. Photochemistry and Photobiology A: Chemistry, 145, 173-181 (2001); Y. G. Yingling and B. J. Garrison, Chem. Phys. Lett., 364, 237-243 (2002).

  14. Radiofrequency Ablation of a Left Atrial Appendage Tachycardia on ECMO Support

    Mohsin Khan

    2013-01-01

    Full Text Available Extracorporeal membrane oxygenation (ECMO has been utilized in the pediatric population for cardiogenic shock secondary to medically intractable arrhythmias. There is limited experience with cardiac radiofrequency ablation (RFA on these patients while on ECMO. A 7-year-old girl presented with a tachycardia-mediated cardiomyopathy secondary to a left atrial appendage tachycardia. She suffered a cardiac arrest due to pulseless electrical activity and was placed on ECMO. Due to elevated left atrial pressures and the refractoriness of her arrhythmia to cardioversion and antiarrhythmic therapy, while on ECMO, blade atrial septostomy and radiofrequency ablation were performed. The patient tolerated the procedure well and was successfully decannulated. Her cardiac function normalized within four weeks of the ablation procedure. Twelve months after the procedure, she remains completely well, with no symptoms or tachycardia.

  15. Interventional radiology neck procedures.

    Zabala Landa, R M; Korta Gómez, I; Del Cura Rodríguez, J L

    2016-05-01

    Ultrasonography has become extremely useful in the evaluation of masses in the head and neck. It enables us to determine the anatomic location of the masses as well as the characteristics of the tissues that compose them, thus making it possible to orient the differential diagnosis toward inflammatory, neoplastic, congenital, traumatic, or vascular lesions, although it is necessary to use computed tomography or magnetic resonance imaging to determine the complete extension of certain lesions. The growing range of interventional procedures, mostly guided by ultrasonography, now includes biopsies, drainages, infiltrations, sclerosing treatments, and tumor ablation.

  16. Remote Magnetic Navigation: A Focus on Catheter Ablation of Ventricular Arrhythmias.

    Aagaard, Philip; Natale, Andrea; Briceno, David; Nakagawa, Hiroshi; Mohanty, Sanghamitra; Gianni, Carola; Burkhardt, J David; DI Biase, Luigi

    2016-03-01

    VT ablation is based on percutaneous catheter insertion under fluoroscopic guidance to selectively destroy (i.e., ablate) myocardial tissue regions responsible for the initiation or propagation of ventricular arrhythmias. Although the last decade has witnessed a rapid evolution of ablation equipment and techniques, the control over catheter movement during manual ablation has remained largely unchanged. Moreover, the procedures are long, and require ergonomically unfavorable positions, which can lead to operator fatigue. In an attempt to overcome these constraints, several technical advancements, including remote magnetic navigation (RMN), have been developed. RMN utilizes a magnetic field to remotely manipulate specially designed soft-tip ablation catheters anywhere in the x, y, or z plane inside the patient's chest. RMN also facilitates titration of the contact force between the catheter and the myocardial tissue, which may reduce the risk of complications while ensuring adequate lesion formation. There are several non-randomized studies showing that RMN has similar efficacy to manual ablation, while complication rates and total radiation exposure appears to be lower. Although these data are promising, larger randomized studies are needed to prove that RMN is superior to manual ablation of VT.

  17. Percutaneous laser ablation of hepatocellular carcinoma in patients with liver cirrhosis awaiting liver transplantation

    Pompili, Maurizio, E-mail: mpompili@rm.unicatt.i [Department of Internal Medicine, Universita Cattolica del Sacro Cuore, Largo A. Gemelli, 8, 00168 Roma (Italy); Pacella, Claudio Maurizio, E-mail: claudiomauriziopacella@gmail.co [Department of Diagnostic Imaging and Interventional Radiology, Ospedale Regina Apostolorum, Via S. Francesco D' Assisi, 50, 00041 Albano Laziale (RM) (Italy); Francica, Giampiero, E-mail: giampierofrancica@tin.i [Department of Interventional Ultrasound, Presidio Ospedaliero Camilliani, S. Maria della Pieta, Via S. Rocco, 9, 80026 Casoria (Namibia) (Italy); Angelico, Mario, E-mail: angelico@med.uniroma2.i [Hepatology Unit, Universita di Tor Vergata, Viale Oxford, 81, 00133 Rome (Italy); Tisone, Giuseppe, E-mail: tisone@med.uniroma2.i [Transplant and General Surgery Unit, Universita di Tor Vergata, Ospedale S. Eugenio, Piazzale dell' Umanesimo 10-00144 Rome (Italy); Craboledda, Paolo, E-mail: paolo.craboledda@virgilio.i [Department of Pathology, Ospedale S. Eugenio, Piazzale dell' Umanesimo, 10-00144 Rome (Italy); Nicolardi, Erica; Rapaccini, Gian Ludovico; Gasbarrini, Giovanni [Department of Internal Medicine, Universita Cattolica del Sacro Cuore, Largo A. Gemelli, 8, 00168 Roma (Italy)

    2010-06-15

    Objective: The aim of this study was to determine the effectiveness and safety of percutaneous laser ablation for the treatment of cirrhotic patients with hepatocellular carcinoma awaiting liver transplantation. Materials and methods: The data of 9 male cirrhotic patients (mean age 50 years, range 45-60 years) with 12 biopsy proven nodules of hepatocellular carcinoma (mean diameter 2.0 cm, range 1.0-3.0 cm) treated by laser ablation before liver transplantation between June 2000 and January 2006 were retrospectively reviewed. Laser ablation was carried out by inserting 300 nm optical fibers through 21-Gauge needles (from two to four) positioned under ultrasound guidance into the target lesions. A continuous wave Neodymium:Yttrium Aluminium Garnet laser was used. Transarterial chemoembolization prior to liver transplantation was performed in two incompletely ablated tumors. Results: No procedure-related major complications were recorded. During the waiting time to liver transplantation local tumor progression after ablation occurred in 3 nodules (25%). At histological examination of the explanted livers complete necrosis was found in 8 nodules (66.7%, all treated exclusively with laser ablation), partial necrosis >50% in 3 nodules (25%), and partial necrosis <50% in 1 nodule. Conclusion: In patients with cirrhotic livers awaiting liver transplantation, percutaneous laser ablation is safe and effective for the management of small hepatocellular carcinoma.

  18. Effects of 5-HT1A receptor agonists and NMDA receptor antagonists in the social interaction test and the elevated plus maze.

    Dunn, R W; Corbett, R; Fielding, S

    1989-10-01

    The effects of several 5-HT1A agonists and excitatory amino acid antagonists were compared to the standard benzodiazepines, diazepam and chlordiazepoxide (CDP) in two assays predictive of anxiolytic activity, the social interaction and elevated plus maze procedures. Indicative of anxiolytic effects the 5-HT1A agonists, buspirone, gepirone and 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) all significantly increased social interaction time and open arm exploration time in the social interaction and elevated plus maze procedures, respectively. Likewise, anxiolytic activity in these assays were also produced by the competitive N-methyl-D-aspartate (NMDA) antagonists, 2-amino-5-phosphonovaleric acid (AP-5), 2-amino-7-phosphonoheptanoic acid (AP-7), 3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) and the non-competitive NMDA antagonist, (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801) while NMDA produced anxiogenic effects. Furthermore, the anxiolytic effects of these agents were of equal magnitude to the benzodiazepines. These two classes of compounds were differentiated in the yohimbine-induced seizure assay, with the NMDA antagonists dose dependently antagonizing seizures similar to the benzodiazepines while the 5-HT1A agonists were inactive. These results suggest that the 5-HT1A agonists and the NMDA antagonists may be potential non-classical anxiolytic agents with different mechanisms of action.

  19. Hydrodynamic instabilities in an ablation front

    Piriz, A R; Portugues, R F [E.T.S.I. Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain)

    2004-06-01

    The hydrodynamic stability of an ablation front is studied for situations in which the wavelength of the perturbations is larger than the distance to the critical surface where the driving radiation is absorbed. An analytical model is presented, and it shows that under conditions in which the thermal flux is limited within the supercritical region of the ablative corona, the front may behave like a flame or like an ablation front, depending on the perturbation wavelength. For relatively long wavelengths the critical and ablation surfaces practically lump together into a unique surface and the front behaves like a flame, whereas for the shortest wavelengths the ablation front substructure is resolved.

  20. Delayed cardiac tamponade: A rare but life-threatening complication of catheter ablation.

    Yetter, Elizabeth; Brazg, Jared; Del Valle, Diane; Mulvey, Laura; Dickman, Eitan

    2016-11-17

    Delayed cardiac tamponade (DCT) is a rare and life-threatening complication of catheter ablation performed as a treatment of atrial fibrillation, with few cases described in the medical literature. We present the case of a 57year-old man presenting with DCT 61days following a catheter ablation procedure. To the best of our knowledge, this is the most delayed case of cardiac tamponade (CT) following catheter ablation described in the literature. We also discuss the importance of point of care ultrasound (POCUS) in the diagnosis and treatment of CT. Emergency physicians must maintain a high index of suspicion in making the diagnosis of CT as patients may present with vague symptoms such as neck or back pain, shortness of breath, fatigue, dizziness, or altered mental status, often without chest pain. Common risk factors for CT include cancer, renal failure, pericarditis, cardiac surgery, myocardial rupture, trauma, and retrograde aortic dissection. In addition, although rare, both catheter ablation and use of anticoagulation carry risks of developing CT. A worldwide survey of medical centers performing catheter ablation found CT as a complication in less than 2% of cases [1]. Some proposed mechanisms of DCT include small pericardial hemorrhages following post-procedural anticoagulation or rupture of the sealed ablation-induced left atrial wall [2]. Clinical examination and electrocardiography may be helpful. However, the criterion standard for diagnosing CT is echocardiography [3].

  1. Reading Assessment Methods for Middle-School Students: An Investigation of Reading Comprehension Rate and Maze Accurate Response Rate

    Hale, Andrea D.; Henning, Jaime B.; Hawkins, Renee O.; Sheeley, Wesley; Shoemaker, Larissa; Reynolds, Jennifer R.; Moch, Christina

    2011-01-01

    This study was designed to investigate the validity of four different aloud reading comprehension assessment measures: Maze, comprehension questions, Maze accurate response rate (MARR), and reading comprehension rate (RCR). The criterion measures used in this study were the Woodcock-Johnson III Tests of Achievement (WJ-III ACH) Broad Reading…

  2. A robust animal model of state anxiety : fear-potentiated behaviour in the elevated plus-maze

    Korte, SM; De Boer, SF

    2003-01-01

    Fear (i.e., decreased percentage time spent on open-arm exploration) in the elevated plus-maze can be potentiated by prior inescapable stressor exposure, but not by escapable stress. The use of fear-potentiated plus-maze behaviour has several advantages as compared to more traditional animal models

  3. Incremental Sentence Processing in Japanese: A Maze Investigation into Scrambled and Control Sentences

    Witzel, Jeffrey; Witzel, Naoko

    2016-01-01

    This study investigates preverbal structural and semantic processing in Japanese, a head-final language, using the maze task. Two sentence types were tested--simple scrambled sentences (Experiment 1) and control sentences (Experiment 2). Experiment 1 showed that even for simple, mono-clausal Japanese sentences, (1) there are online processing…

  4. Comparing Exploration Strategies for Q-learning in Random Stochastic Mazes

    Tijsma, Arryon; Drugan, Madalina; Wiering, Marco

    2016-01-01

    Balancing the ratio between exploration and exploitation is an important problem in reinforcement learning. This paper evaluates four different exploration strategies combined with Q-learning using random stochastic mazes to investigate their performances. We will compare: UCB-1, softmax, epsilon-gr

  5. Anxiolytic effect of clonazepam in female rats: grooming microstructure and elevated plus maze tests.

    Nin, Maurício S; Couto-Pereira, Natividade S; Souza, Marilise F; Azeredo, Lucas A; Ferri, Marcelo K; Dalprá, Walesca L; Gomez, Rosane; Barros, Helena M T

    2012-06-01

    Grooming behavior is an adaptation to a stressful environment that can vary in accordance with stress intensity. Direct and indirect GABA(A) receptor agonists decrease duration, frequency, incorrect transitions and uninterrupted bouts of grooming. Hormonal variation during the different phases of the estrous cycle of female rats also changes the grooming behavior. It is known that GABA(A) agonists and endogenous hormones change anxiety-like behaviors observed in the elevated plus maze test, a classical animal model of anxiety. This study was designed to determine the anxiolytic effect of clonazepam in female rats in different estrous phases and to correlate anxiety behaviors in the elevated plus maze and grooming microstructure tests. Our results show that female rats displayed higher anxiety-like behavior scores during the estrus and proestrus phases in the elevated plus maze and that clonazepam (0.25 mg/kg; i.p.) had an anxiolytic effect that was independent of the estrous phase. Grooming behaviors were higher in the proestrus phase but were decreased by clonazepam administration, independent of the estrous phase, demonstrating the anxiolytic effect of this drug in both animal models. Grooming behaviors were moderately associated with anxiolytic-like behaviors in the elevated plus maze test. Here, we describe the anxiolytic effect of clonazepam and the influence of estrous phase on anxiety. Moreover, we show that the grooming microstructure test is a useful tool for detecting anxiolytic-like behaviors in rats.

  6. Comparison of transcatheter laser and direct-current shock ablation of endocardium near tricuspid anulus

    Zhang, Yu-Zhen; Wang, Shi-Wen; Li, Junheng

    1993-03-01

    Forty to eighty percent of the patients with accessory pathways (APs) manifest themselves by tachyarrhythmias. Many of these patients needed either life-long medical therapy or surgery. In order to avoid the discomfort and expenses in surgical procedures, closed chest percutaneous catheter ablation of APs became a potentially desirable therapeutic approach. Many investigations indicated that ablation of right APs by transcatheter direct current (dc) shock could cause life-threatening arrhythmias, right coronary arterical (RCA) spasm, etc. With the development of transcatheter laser technique, it has been used in drug-incurable arrhythmias. The results show that laser ablation is much safer than surgery and electric shock therapy. The purpose of this study is to explore the effectiveness, advantages, and complications with transcatheter Nd:YAG laser and dc shock in the ablation of right atrioventricular accessory pathways in the atrium near the tricuspid annulus (TA) in 20 dogs.

  7. Palliative Treatment of Rectal Carcinoma Recurrence Using Radiofrequency Ablation

    Mylona, Sophia, E-mail: mylonasophia@yahoo.com; Karagiannis, Georgios, E-mail: gekaragiannis@yahoo.gr; Patsoura, Sofia, E-mail: sofia.patsoura@yahoo.gr [Hellenic Red Cross Hospital ' Korgialenio-Benakio' (Greece); Galani, Panagiota, E-mail: gioulagalani@yahoo.com [Amalia Fleming Hospital (Greece); Pomoni, Maria, E-mail: marypomoni@gmail.com [Evgenidion Hospital (Greece); Thanos, Loukas, E-mail: loutharad@yahoo.com [Sotiria Hospital (Greece)

    2012-08-15

    Purpose: To evaluate the safety and efficacy of CT-guided radiofrequency (RF) ablation for the palliative treatment of recurrent unresectable rectal tumors. Materials and Methods: Twenty-seven patients with locally recurrent rectal cancer were treated with computed tomography (CT)-guided RF ablation. Therapy was performed with the patient under conscious sedation with a seven- or a nine-array expandable RF electrode for 8-10 min at 80-110 Degree-Sign C and a power of 90-110 W. All patients went home under instructions the next day of the procedure. Brief Pain Inventory score was calculated before and after (1 day, 1 week, 1 month, 3 months, and 6 months) treatment. Results: Complete tumor necrosis rate was 77.8% (21 of a total 27 procedures) despite lesion location. BPI score was dramatically decreased after the procedure. The mean preprocedure BPI score was 6.59, which decreased to 3.15, 1.15, and 0.11 at postprocedure day 1, week 1, and month 1, respectively, after the procedure. This decrease was significant (p < 0.01 for the first day and p < 0.001 for the rest of the follow-up intervals (paired Student t test; n - 1 = 26) for all periods during follow-up. Six patients had partial tumor necrosis, and we were attempted to them with a second procedure. Although the necrosis area showed a radiographic increase, no complete necrosis was achieved (secondary success rate 65.6%). No immediate or delayed complications were observed. Conclusion: CT-guided RF ablation is a minimally invasive, safe, and highly effective technique for treatment of malignant rectal recurrence. The method is well tolerated by patients, and pain relief is quickly achieved.

  8. Virtual cardioscopy: interactive endocardial visualization to guide RF cardiac ablation

    Holmes, David R., III; Rettmann, Maryam E.; Cameron, Bruce M.; Camp, Jon J.; Robb, Richard A.

    2006-03-01

    Cardiac arrhythmias are a debilitating, potentially life threatening condition involving aberrant electrical activity in the heart which results in abnormal heart rhythm. Virtual cardioscopy can play an important role in minimally invasive treatment of cardiac arrhythmias. Second and third generation image-guidance systems are now available for the treatment of arrhythmias using RF ablation catheters. While these 3D tools provide useful information to the clinician, additional enhancements to the virtual cardioscopy display paradigm are critical for optimal therapy guidance. Based on input from clinical collaborators, several key visualization techniques have been developed to enhance the use of virtual cardioscopy during cardiac ablation procedures. We have identified, designed and incorporated several visual cues important to successful virtual cardioscopy. These features include the use of global reference maps, parametric mapping, and focused navigation and targeting using abnormal electro-physiologic activity. Our virtual cardioscopy system is designed for real-time use during RF cardiac ablation procedures. Several unique visualizations from our virtual cardioscopy system will be presented. Evaluation of the system with phantom and animal studies will be presented. This research is supported by grant EB002834 from the National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health.

  9. Management of refractory atrial fibrillation post surgical ablation

    Altman, Robert K.; Proietti, Riccardo; Barrett, Conor D.; Paoletti Perini, Alessandro; Santangeli, Pasquale; Danik, Stephan B.; Di Biase, Luigi

    2014-01-01

    Over the past two decades, invasive techniques to treat atrial fibrillation (AF) including catheter-based and surgical procedures have evolved along with our understanding of the pathophysiology of this arrhythmia. Surgical treatment of AF may be performed on patients undergoing cardiac surgery for other reasons (concomitant surgical ablation) or as a stand-alone procedure. Advances in technology and technique have made surgical intervention for AF more widespread. Despite improvements in outcome of both catheter-based and surgical treatment for AF, recurrence of atrial arrhythmias following initial invasive therapy may occur.Atrial arrhythmias may occur early or late in the post-operative course after surgical ablation. Early arrhythmias are generally treated with prompt electrical cardioversion with or without antiarrhythmic therapy and do not necessarily represent treatment failure. The mechanism of persistent or late occurring atrial arrhythmias is complex, and these arrhythmias may be resistant to antiarrhythmic drug therapy. The characterization and management of recurrent atrial arrhythmias following surgical ablation of AF are discussed below. PMID:24516805

  10. Ablation of premature ventricular complexes exclusively guided by three-dimensional noninvasive mapping.

    Erkapic, Damir; Neumann, Thomas

    2015-03-01

    Preprocedural detailed characterization of premature ventricular complexes before ablation, currently limited to the 12-lead electrocardiogram, may aid in planning and improve procedural outcomes. This article summarizes current published data on feasibility, accuracy, and impact on clinical outcomes of a novel, three-dimensional, noninvasive, single-beat mapping system (ECVUE, CardioInsight). ECVUE technology offers premature ventricular complex characterization and localization with clinically relevant accuracy and performance superior to the surface electrocardiogram. With its noninvasive and single beat advantages, ECVUE has the potential to simplify mapping, and reduce ablation and procedural time.

  11. Are benzodiazepines really anxiolytic? Evidence from a 3D maze spatial navigation task.

    Ennaceur, A; Michalikova, S; van Rensburg, R; Chazot, P L

    2008-03-17

    The effects of diazepam and chlordiazepoxide were assessed in a 3D maze which is a modification of an 8-arm radial maze. Each arm of the maze is attached to a bridge radiating from a central platform. Animals exposed for the first time to the maze do not venture beyond the line that separate a bridge from an arm. The prime criteria set for an anxiolytic effect is whether mice would increase the frequency of entries onto arms and increase arm/bridge entries ratio. C57 mice readily cross the line on first exposure and make more than 8 arm visits onto arms on second exposure, while other strains (CD-1 and Balb/c) hold back and rarely cross the line on first exposure and require more sessions to make more than 8 arm entries. An anxiolytic drug is expected to encourage intermediate (CD-1) and high (Balb/c) anxiety mice to adventure onto the arms of the maze and make more visits to the arms to comparable levels seen with low anxiety c57 mice. In the present report, administration of different doses of diazepam (0.625, 1.25, 2.5 and 5 mg kg(-1) i.p.) and chlordiazepoxide (5, 10 and 15 mg kg(-1) i.p.) did not reduce anxiety in animals, with the lowest dose of diazepam increasing motor activity in Balb/c and increasing anxiety in c57 mice while the highest doses of both diazepam (2.5 and 5 mg kg(-1) i.p.) and chlordiazepoxide (15 mg kg(-1) i.p.) induced mild sedation. Our results raise some concerns about the methodological foundations in the current assessment of anxiety and anxiolytic compounds both in animal and human studies.

  12. Fast and automatic depth control of iterative bone ablation based on optical coherence tomography data

    Fuchs, Alexander; Pengel, Steffen; Bergmeier, Jan; Kahrs, Lüder A.; Ortmaier, Tobias

    2015-07-01

    Laser surgery is an established clinical procedure in dental applications, soft tissue ablation, and ophthalmology. The presented experimental set-up for closed-loop control of laser bone ablation addresses a feedback system and enables safe ablation towards anatomical structures that usually would have high risk of damage. This study is based on combined working volumes of optical coherence tomography (OCT) and Er:YAG cutting laser. High level of automation in fast image data processing and tissue treatment enables reproducible results and shortens the time in the operating room. For registration of the two coordinate systems a cross-like incision is ablated with the Er:YAG laser and segmented with OCT in three distances. The resulting Er:YAG coordinate system is reconstructed. A parameter list defines multiple sets of laser parameters including discrete and specific ablation rates as ablation model. The control algorithm uses this model to plan corrective laser paths for each set of laser parameters and dynamically adapts the distance of the laser focus. With this iterative control cycle consisting of image processing, path planning, ablation, and moistening of tissue the target geometry and desired depth are approximated until no further corrective laser paths can be set. The achieved depth stays within the tolerances of the parameter set with the smallest ablation rate. Specimen trials with fresh porcine bone have been conducted to prove the functionality of the developed concept. Flat bottom surfaces and sharp edges of the outline without visual signs of thermal damage verify the feasibility of automated, OCT controlled laser bone ablation with minimal process time.

  13. Ablation characteristics of special concrete due to an impinging zirconium-dioxide melt jet

    An, S.M., E-mail: sangmoan@kaeri.re.kr; Ha, K.S.; Min, B.T.; Kim, H.Y.; Song, J.H.

    2015-04-01

    Highlights: • The jet impingement tests were performed for a special concrete of core-catcher. • The ablation rate and depth were measured 1.59 mm/s and 4.33 mm, respectively. • The experimental results were estimated well between the model prediction bounds. • The material ablation was described reasonably by a convective heat transfer model. - Abstract: Jet impingement experiments were performed to investigate the ablation characteristics of special concrete, which has been developed as one of the candidate protecting materials for the EU-APR1400 ex-vessel core catcher. In order to simulate the jet impingement phenomenon owing to the reactor vessel failure during a severe core meltdown accident, the experimental facility was established and the experimental conditions were determined based on parametric studies. The special concrete specimen was manufactured in accordance with the standard procedures, and its microstructures and physicochemical properties were analyzed to verify the requirements for the qualification. An induction melting technique in a cold crucible was employed to generate the zirconium-dioxide melt as a simulant of the corium melt. The special concrete was ablated uniformly over the impact area by jet impingement, and the average ablation depth was measured to be 4.33 mm. The average ablation rate in depth was evaluated as 1.59 mm/s using the temperature measurements of the specimen. As compared with the predictions by the models based on the convective and radiative heat transfer analysis, both the measured ablation rate and depth were estimated appropriately within the bounds of their limits. However, the convective heat transfer model turned out to predict the ablation characteristics of the special concrete more reasonably during the jet impingement even though some water content within the special concrete could lead to a sudden generation of the steam layer through which the material ablation is attenuated substantially by the

  14. Ablation dynamics in laser sclerotomy ab externo

    Brinkmann, Ralf; Droege, Gerit; Mohrenstecher, Dirk; Scheu, M.; Birngruber, Reginald

    1996-01-01

    Laser sclerostomy ab externo with flashlamp excited mid-IR laser systems emitting in the 2-3 micrometer spectral range is in phase II clinical trials. Although acutely high success rates were achieved, the restenosis rate after several months is about 40%. Laser pulses of several hundreds of microseconds, known to induce thermo-mechanical explosive evaporation were used for this procedure. We investigated the ablation dynamics in tissue and the cavitation bubble dynamics in water by means of an Er:YAG laser system to estimate the extent of mechanical damage zones in the sclera and in the anterior chamber, which may contribute to the clinical failure. We found substantial mechanical tissue deformation during the ablation process caused by the cavitation effects. Stress waves up to several bar generated by explosive evaporization were measured. The fast mechanical stretching and collapsing of the scleral tissue induced by cavitation resulted in tissue dissection as could be proved by flash photography and histology. The observed high restenosis might be a result of a subsequent enhanced wound healing process. Early fistula occlusions due to iris adherences, observed in about 20% of the clinical cases may be attributed to intraocular trauma induced by vapor bubble expansion through the anterior chamber after scleral perforation. An automatic feedback system minimizing adverse effects by steering and terminating the laser process during scleral fistulization is demonstrated. Moreover, a new approach in laser sclerostomy ab externo is presented using a cw-IR laser diode system emitting at the 1.94 micrometer mid-IR water absorption peak. This system was used in vitro and showed smaller damage zones compared to the pulsed laser radiation.

  15. Endovascular Radiofrequency Ablation for Varicose Veins

    2011-01-01

    treatment plan. The RFA procedure involves the introduction of a guide wire into the target vein under ultrasound guidance followed by the insertion of an introducer sheath through which the RFA catheter is advanced. Once satisfactory positioning has been confirmed with ultrasound, a tumescent anaesthetic solution is injected into the soft tissue surrounding the target vein along its entire length. This serves to anaesthetize the vein, insulate the heat from damaging adjacent structures, including nerves and skin and compresses the vein increasing optimal contact of the vessel wall with the electrodes or expanded prongs of the RF device. The RF generator is then activated and the catheter is slowly pulled along the length of the vein. At the end of the procedure, hemostasis is then achieved by applying pressure to the vein entry point. Adequate and proper compression stockings and bandages are applied after the procedure to reduce the risk of venous thromboembolism and to reduce postoperative bruising and tenderness. Patients are encouraged to walk immediately after the procedure. Follow-up protocols vary, with most patients returning 1 to 3 weeks later for an initial follow-up visit. At this point, the initial clinical result is assessed and occlusion of the treated vessels is confirmed with ultrasound. Patients often have a second follow-up visit 1 to 3 months following RFA at which time clinical evaluation and ultrasound are repeated. If required, additional procedures such as phlebectomy or sclerotherapy may be performed during the RFA procedure or at any follow-up visits. Regulatory Status The Closure System® radiofrequency generator for endovascular thermal ablation of varicose veins was approved by Health Canada as a class 3 device in March 2005, registered under medical device license 67865. The RFA intravascular catheter was approved by Health Canada in November 2007 for the ClosureFast catheter, registered under medical device license 16574. The Closure System

  16. Laser Ablation Propulsion A Study

    Irfan, Sayed A.; Ugalatad, Akshata C.

    Laser Ablation Propulsion (LAP) will serve as an alternative propulsion system for development of microthrusters. The principle of LAP is that when a laser (pulsed or continuous wave) with sufficient energy (more than the vaporization threshold energy of material) is incident on material, ablation or vaporization takes place which leads to the generation of plasma. The generated plasma has the property to move away from the material hence pressure is generated which leads to the generation of thrust. Nowadays nano satellites are very common in different space and defence applications. It is important to build micro thruster which are useful for orienting and re-positioning small aircraft (like nano satellites) above the atmosphere. modelling of LAP using MATLAB and Mathematica. Schematic is made for the suitable optical configuration of LAP. Practical experiments with shadowgraphy and self emission techniques and the results obtained are analysed taking poly (vinyl-chloride) (PVC) as propellant to study the

  17. The effect of a paraffin screen on the neutron dose at the maze door of a 15 MV linear accelerator

    Krmar, M.; Kuzmanović, A. [Physics Department, Faculty of Science, University of Novi Sad, Novi Sad 21000 (Serbia); Nikolić, D. [National Institute for Nanotechnology, Edmonton, Alberta T6G 2M9 (Canada); Kuzmanović, Z. [International Medical Centers, Banja Luka 78000, Republika Srpska, Bosnia and Herzegovina (Bosnia and Herzegowina); Ganezer, K. [Physics Department, California State University Dominguez Hills, Carson, California 90747 (United States)

    2013-08-15

    Purpose: The purpose of this study was to explore the effects of a paraffin screen located at various positions in the maze on the neutron dose equivalent at the maze door.Methods: The neutron dose equivalent was measured at the maze door of a room containing a 15 MV linear accelerator for x-ray therapy. Measurements were performed for several positions of the paraffin screen covering only 27.5% of the cross-sectional area of the maze. The neutron dose equivalent was also measured at all screen positions. Two simple models of the neutron source were considered in which the first assumed that the source was the cross-sectional area at the inner entrance of the maze, radiating neutrons in an isotropic manner. In the second model the reduction in the neutron dose equivalent at the maze door due to the paraffin screen was considered to be a function of the mean values of the neutron fluence and energy at the screen.Results: The results of this study indicate that the equivalent dose at the maze door was reduced by a factor of 3 through the use of a paraffin screen that was placed inside the maze. It was also determined that the contributions to the dosage from areas that were not covered by the paraffin screen as viewed from the dosimeter, were 2.5 times higher than the contributions from the covered areas. This study also concluded that the contributions of the maze walls, ceiling, and floor to the total neutron dose equivalent were an order of magnitude lower than those from the surface at the far end of the maze.Conclusions: This study demonstrated that a paraffin screen could be used to reduce the neutron dose equivalent at the maze door by a factor of 3. This paper also found that the reduction of the neutron dose equivalent was a linear function of the area covered by the maze screen and that the decrease in the dose at the maze door could be modeled as an exponential function of the product φ·E at the screen.

  18. Transient Ablation Regime in Circuit Breakers

    Alexandre MARTIN; Jean-Yves TREPANIER; Marcelo REGGIO; GUO Xue-yan

    2007-01-01

    Nozzle wall ablation caused by high temperature electric arcs is studied in the context of high voltage SF6 circuit breakers.The simplified ablation model used in litterature has been updated to take into account the unsteady state of ablation.Ablation rate and velocity are now calculated by a kinetic model using two layers of transition,between the bulk plasma and the ablating wall.The first layer (Knudsen layer),right by the wall,is a kinetic layer of a few mean-free path of thickness.The second layer is collision dominated and makes the transition between the kinetic layer and the plasma bulk.With this new coupled algorithm,it is now possible to calculate the temperature distribution inside the wall,as well as more accurate ablation rates.

  19. Single-shot and single-spot measurement of laser ablation threshold for carbon nanotubes

    Lednev, Vasily N; Obraztsova, Elena D; Kudryashov, Sergey I; Bunkin, Alexey F

    2013-01-01

    A simple and convenient procedure for single-shot, single-spot ablation threshold measurement has been developed. It is based on the employment of cylindrical lens to obtain elliptical Gaussian laser spot. The ablated spot chords which are parallel to the minor axis were measured across the spot major axis which is proportional to the fluence cross-section thus providing wide range dependence of damaged spot size versus fluence in one spot measurement. For both conventional and new-developed procedures the ablation threshold for typical Nd:YAG laser parameters (1064 nm, 10 ns) has been measured as 50 mJ/cm2 which is one order of magnitude lower than that for a bulk graphite.

  20. Neocuproine Ablates Melanocytes in Adult Zebrafish

    O'Reilly-Pol, Thomas; Johnson, Stephen L.

    2008-01-01

    The simplest regeneration experiments involve the ablation of a single cell type. While methods exist to ablate the melanocytes of the larval zebrafish,1,2 no convenient method exists to ablate melanocytes in adult zebrafish. Here, we show that the copper chelator neocuproine (NCP) causes fragmentation and disappearance of melanin in adult zebrafish melanocytes. Adult melanocytes expressing eGFP under the control of a melanocyte-specific promoter also lose eGFP fluorescence in the presence of...

  1. Computer-aided hepatic tumour ablation

    Voirin, D; Amavizca, M; Leroy, A; Letoublon, C; Troccaz, J; Voirin, David; Payan, Yohan; Amavizca, Miriam; Leroy, Antoine; Letoublon, Christian; Troccaz, Jocelyne

    2001-01-01

    Surgical resection of hepatic tumours is not always possible. Alternative techniques consist in locally using chemical or physical agents to destroy the tumour and this may be performed percutaneously. It requires a precise localisation of the tumour placement during ablation. Computer-assisted surgery tools may be used in conjunction to these new ablation techniques to improve the therapeutic efficiency whilst benefiting from minimal invasiveness. This communication introduces the principles of a system for computer-assisted hepatic tumour ablation.

  2. Efficacy comparison between cryoablation and radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter: a meta-analysis

    Chen, Yi-He; Lin, Hui; Xie, Cheng-Long; Zhang, Xiao-Ting; Li, Yi-Gang

    2015-06-01

    We perform this meta-analysis to compare the efficacy and safety of cryoablation versus radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter. By searching EMBASE, MEDLINE, PubMed and Cochrane electronic databases from March 1986 to September 2014, 7 randomized clinical trials were included. Acute (risk ratio[RR]: 0.93; P = 0.14) and long-term (RR: 0.94; P = 0.08) success rate were slightly lower in cryoablation group than in radiofrequency ablation group, but the difference was not statistically significant. Additionally, the fluoroscopy time was nonsignificantly reduced (weighted mean difference[WMD]: -2.83 P = 0.29), whereas procedure time was significantly longer (WMD: 25.95; P = 0.01) in cryoablation group compared with radiofrequency ablation group. Furthermore, Pain perception during the catheter ablation was substantially less in cryoabaltion group than in radiofrequency ablation group (standardized mean difference[SMD]: -2.36 P < 0.00001). Thus, our meta-analysis demonstrated that cryoablation and radiofrequency ablation produce comparable acute and long-term success rate for patients with cavotricuspid valve isthmus dependent atrial flutter. Meanwhile, cryoablation ablation tends to reduce the fluoroscopy time and significantly reduce pain perception in cost of significantly prolonged procedure time.

  3. Feedback control strategies for spatial navigation revealed by dynamic modelling of learning in the Morris water maze.

    Fey, Dirk; Commins, Sean; Bullinger, Eric

    2011-04-01

    The Morris water maze is an experimental procedure in which animals learn to escape swimming in a pool using environmental cues. Despite its success in neuroscience and psychology for studying spatial learning and memory, the exact mnemonic and navigational demands of the task are not well understood. Here, we provide a mathematical model of rat swimming dynamics on a behavioural level. The model consists of a random walk, a heading change and a feedback control component in which learning is reflected in parameter changes of the feedback mechanism. The simplicity of the model renders it accessible and useful for analysis of experiments in which swimming paths are recorded. Here, we used the model to analyse an experiment in which rats were trained to find the platform with either three or one extramaze cue. Results indicate that the 3-cues group employs stronger feedback relying only on the actual visual input, whereas the 1-cue group employs weaker feedback relying to some extent on memory. Because the model parameters are linked to neurological processes, identifying different parameter values suggests the activation of different neuronal pathways.

  4. Aromatic Thermosetting Copolyesters for Ablative TPS Project

    National Aeronautics and Space Administration — Better performing ablative thermal protection systems than currently available are needed to satisfy requirements of the most severe crew exploration vehicles, such...

  5. Laser ablation for small hepatocellular carcinoma: State of the art and future perspectives

    Giovan; Giuseppe; Di; Costanzo; Giampiero; Francica; Claudio; Maurizio; Pacella

    2014-01-01

    During the last two decades, various local thermal ablative techniques for the treatment of unresectable hepatocellular carcinoma(HCC) have been developed. According to internationally endorsed guidelines, percutaneous thermal ablation is the mainstay of treatment in patients with small HCC who are not candidates for surgical resection or transplantation. Laser ablation(LA) represents one of currently available loco-ablative techniques. In this article, the general principles, technique, image guidance, and patient selection are reported. Primary effectiveness, long-term outcome, and complications are also discussed. A review of published data suggests that LA is equivalent to the more popular and widespread radiofrequency ablation in both local tumor control and long-term outcome in the percutaneous treatment of early HCC. In addition, the LA technique using multiple thin laser fibres allows improved ablative effectiveness in HCCs greater than 3 cm. Reference centres should be equipped with all the available techniques so as to be able to use the best and the most suitable procedure for each type of lesion for each patient.

  6. Ultrasound-guided percutaneous radiofrequency ablation of liver tumors: How we do it safety and completely

    Kim, Jin Woong; Shin, Sang Soo; Heo, Suk Hee; Hong, Jun Hyung; Lim, Hyo Soon; Seon, Hyun Ju; Hur, Young Hoe; Park, Chang Hwan; Jeong, Yong Yeon; Kang, Heoung Keun [Chonnam National University Medical School, Gwangju (Korea, Republic of)

    2015-12-15

    Ultrasound-guided percutaneous radiofrequency (RF) ablation has become one of the most promising local cancer therapies for both resectable and nonresectable hepatic tumors. Although RF ablation is a safe and effective technique for the treatment of liver tumors, the outcome of treatment can be closely related to the location and shape of the tumors. There may be difficulties with RF ablation of tumors that are adjacent to large vessels or extrahepatic heat-vulnerable organs and tumors in the caudate lobe, possibly resulting in major complications or treatment failure. Thus, a number of strategies have been developed to overcome these challenges, which include artificial ascites, needle track ablation, fusion imaging guidance, parallel targeting, bypass targeting, etc. Operators need to use the right strategy in the right situation to avoid the possibility of complications and incomplete thermal tissue destruction; with the right strategy, RF ablation can be performed successfully, even for hepatic tumors in high-risk locations. This article offers technical strategies that can be used to effectively perform RF ablation as well as to minimize possible complications related to the procedure with representative cases and schematic illustrations.

  7. Search Strategies Used by "APP" Transgenic Mice during Navigation in the Morris Water Maze

    Janus, Christopher

    2004-01-01

    TgCRND8 mice represent a transgenic mouse model of Alzheimer's disease, with onset of cognitive impairment and increasing amyloid-[beta] plaques in their brains at 12 weeks of age. In this study, the spatial memory in 25- to 30-week-old TgCRND8 mice was analyzed in two reference and one working memory Morris water maze (MWM) tests. In reference…

  8. Anxiolytic-induced attenuation of thigmotaxis in the Elevated Minus Maze.

    Pickles, A R; Hendrie, C A

    2013-07-01

    Findings using exploration models of anxiety such as the Elevated Plus Maze (EPM) and Elevated Zero Maze (EZM) are remarkably consistent given the differences in layout and number of walls used to describe their closed areas. These factors therefore do not appear to be critical. The present studies were conducted to determine if anxiolytic activity could be detected using an apparatus that presented animals with only one wall. Mice were pre-treated with either vehicle, diazepam (2-4 mg/kg) or 5-10 mg/kg chlordiazepoxide (CDP) and placed for 5 min onto a square platform containing a 12 cm × 14 cm wall. Measures were taken of frequency/duration of contacts with the wall and of general activity. Time spent in contact with the wall was selectively reduced by 4 mg/kg diazepam. 10 mg/kg CDP also decreased this measure but increased measures of general activity, indicating a possible mild stimulant effect. The closed areas of the EPM are described by 3 walls. The EZM uses 2. Current findings show that anxiolytic effects can also be detected in a model with just one wall. It could and these data provide further evidence that variations in the layout of these mazes are not critical for detecting anxiolytic action. Thigmotactic cues remain present regardless of the physical characteristics of these mazes or the local conditions they are employed under. Hence, it is suggested that thigmotactic cues may be the common source of motivation to behave in these models and that this may explain their robustness.

  9. Comparisons of Online Reading Paradigms: Eye Tracking, Moving-Window, and Maze

    Witzel, Naoko; Witzel, Jeffrey; Forster, Kenneth

    2012-01-01

    This study compares four methodologies used to examine online sentence processing during reading. Specifically, self-paced, non-cumulative, moving-window reading (Just et al. in "J Exp Psychol Gen" 111:228-238, 1982), eye tracking (see e.g., Rayner in "Q J Exp Psychol" 62:1457-1506, 2009), and two versions of the maze task (Forster et al. in…

  10. What is the most sensitive measure of water maze probe test performance?

    Hamid R Maei

    2009-03-01

    Full Text Available The water maze is commonly used to assay spatial cognition, or, more generally, learning and memory in experimental rodent models. In the water maze, mice or rats are trained to navigate to a platform located below the water’s surface. Spatial learning is then typically assessed in a probe test, where the platform is removed from the pool and the mouse or rat is allowed to search for it. Performance in the probe test may then be evaluated using either occupancy-based (percent time in virtual quadrant [Q] or zone [Z] centered on former platform location, error-based (mean proximity to former platform location [P] or counting-based (platform crossings [X] measures. While these measures differ in their popularity, whether they differ in their ability to detect group differences is not known. To address this question we compiled 5 separate databases, containing more than 1600 mouse probe tests. Random selection of individual trials from respective databases then allowed us to simulate experiments with varying sample and effect sizes. Using this Monte Carlo-based method, we found that the P measure consistently outperformed the Q, Z and X measures in its ability to detect group differences. This was the case regardless of sample or effect size, and using both parametric and non-parametric statistical analyses. The relative superiority of P over other commonly used measures suggests that it is the most appropriate measure to employ in both low- and high-throughput water maze screens.

  11. Fractal dimensions: A new paradigm to assess spatial memory and learning using Morris water maze.

    Singh, Surjeet; Kaur, Harpreet; Sandhir, Rajat

    2016-02-15

    Morris water maze has been widely used for analysis of cognitive functions and relies on the time taken by animal to find the platform i.e. escape latency as a parameter to quantify spatial memory and learning. However, escape latency is confounded by swimming speed which is not necessarily a cognitive factor. Rather, path length may be a more appropriate and reliable parameter to assess spatial learning. This paper presents fractal dimension as a new paradigm to assess spatial memory and learning in animals. Male wistar rats were administrated with pentylenetetrazole and scopolamine to induce chronic epilepsy and dementia respectively. Fractal dimension of the random path followed by the animals on Morris water maze was analyzed and statistically compared among different experimental groups; the results suggest that fractal dimension is more reliable and accurate parameter to assess cognitive deficits compared to escape latency. Thus, the present study suggests that fractal dimensions could be used as an independent parameter to assess spatial memory and learning in animals using Morris water maze.

  12. Memory-impairing effects of local anesthetics in an elevated plus-maze test in mice

    S.L. Blatt

    1998-04-01

    Full Text Available Post-training intracerebroventricular administration of procaine (20 µg/µl and dimethocaine (10 or 20 µg/µl, local anesthetics of the ester class, prolonged the latency (s in the retention test of male and female 3-month-old Swiss albino mice (25-35 g body weight; N = 140 in the elevated plus-maze (mean ± SEM for 10 male mice: control = 41.2 ± 8.1; procaine = 78.5 ± 10.3; 10 µg/µl dimethocaine = 58.7 ± 12.3; 20 µg/µl dimethocaine = 109.6 ± 5.73; for 10 female mice: control = 34.8 ± 5.8; procaine = 55.3 ± 13.4; 10 µg/µl dimethocaine = 59.9 ± 12.3 and 20 µg/µl dimethocaine = 61.3 ± 11.1. However, lidocaine (10 or 20 µg/µl, an amide class type of local anesthetic, failed to influence this parameter. Local anesthetics at the dose range used did not affect the motor coordination of mice exposed to the rota-rod test. These results suggest that procaine and dimethocaine impair some memory process(es in the plus-maze test. These findings are interpreted in terms of non-anesthetic mechanisms of action of these drugs on memory impairment and also confirm the validity of the elevated plus-maze for the evaluation of drugs affecting learning and memory in mice

  13. Place and Response Learning in the Open-field Tower Maze.

    Lipatova, Olga; Campolattaro, Matthew M; Toufexis, Donna J; Mabry, Erin A

    2015-10-28

    This protocol describes how the Open-field Tower Maze (OFTM) paradigm is used to study spatial learning in rodents. This maze is especially useful for examining how rats learn to use a place- or response-learning to successfully navigate in an open-field arena. Additionally, this protocol describes how the OFTM differs from other behavioral maze paradigms that are commonly used to study spatial learning in rodents. The OFTM described in this article was adapted from the one previously described by Cole, Clipperton, and Walt (2007). Specifically, the OFTM was created to test spatial learning in rodents without the experimenter having to consider how "stress" might play a role as a confounding variable. Experiments have shown that stress-alone can significantly affect cognitive function(1). The representative results section contains data from an experiment that used the OFTM to examine the effects of estradiol treatment on place- and response-learning in adult female Sprague Dawley rats(2). Future studies will be designed to examine the role of the hippocampus and striatum in place- and response-learning in the OFTM.

  14. Cortical gene transcription response patterns to water maze training in aged mice

    Martin Bronwen

    2011-06-01

    Full Text Available Abstract Background The hippocampus mediates the acquisition of spatial memory, but the memory trace is eventually transferred to the cortex. We have investigated transcriptional activation of pathways related to cognitive function in the cortex of the aged mouse by analyzing gene expression following water maze training. Results We identified genes that were differentially responsive in aged mice with accurate spatial performance during probe trials or repeated swimming sessions, relative to home cage conditions. Effective learners exhibited significantly greater activation of several pathways, such as the mitogen-activated protein kinase and insulin receptor signaling pathways, relative to swimmers. The genes encoding activity-related cytoskeletal protein (Arc and brain-derived neurotrophic factor (BDNF were upregulated in proficient learners, relative to swimmers and home cage controls, while the gene encoding Rho GTPase activating protein 32 (GRIT was downregulated. We explored the regulation of Arc, BDNF, and GRIT expression in greater morphological detail using in situ hybridization. Recall during probe trials enhanced Arc expression across multiple cortical regions involved in the cognitive component of water maze learning, while BDNF expression was more homogeneously upregulated across cortical regions involved in the associational and sensorimotor aspects of water maze training. In contrast, levels of GRIT expression were uniformly reduced across all cortical regions examined. Conclusions These results suggest that cortical gene transcription is responsive to learning in aged mice that exhibit behavioral proficiency, and support a distributed hypothesis of memory storage across multiple cortical compartments.

  15. Micropatterned polysaccharide surfaces via laser ablation for cell guidance

    Barbucci, Rolando; Lamponi, Stefania; Pasqui, Daniela; Rossi, Antonella; Weber, Elisabetta

    2003-03-03

    Micropatterned materials were obtained by a controlled laser ablation of a photoimmobilised homogeneous layer of hyaluronic acid (Hyal) and its sulphated derivative (HyalS). The photoimmobilisation was performed by coating the polysaccharide, adequately functionalised with a photoreactive group, on aminosilanised glass substrate and immobilising it on the surface under UV light. Hyal or HyalS photoimmobilised samples were then subjected to laser ablation with wavelengths in the UV regions in order to drill the pattern. Four different patterns with stripes of 100, 50, 25 and 10 {mu}m were generated. A chemical characterisation by attenuated total reflection/Fourier transform infrared (ATR/FT-IR) and time of flight-secondary ions mass spectrometry (TOF-SIMS) confirmed the success of the laser ablation procedure and the presence of alternating stripes of polysaccharide and native glass. The exact dimensions of the stripes were determined by atomic force microscopy. The analysis of cell behaviour in terms of adhesion, proliferation and movement using mouse fibroblasts (3T3 line) and bovine aortic endothelial cells (BAEC) was also performed.

  16. Epicardial Ventricular Tachycardia Ablation: Clinical Practice and Recent Developments

    Michalis Efremidis MD

    2011-08-01

    Full Text Available Mapping and radiofrequency (RF catheter ablation of ventricular tachycardia (VT is a demanding procedure, with variable success rates (1. The presence of deep subendocardial or epicardial re-entry circuits is regarded as one of the reasons of failure of endocardial ablation, and these circuits have been acknowledged in ischemic and non-ischemic dilated cardiomyopathy (CMP, other types of CMP and especially in arrhythmogenic right ventricular cardiomyopathy (ARVC.The significance of epicardial VT circuits was brought to light in Chagas’ disease, which characteristically results in epicardial involvement in approximately 70% of patients (2. A recent study found one third of VTs to be epicardial in origin among patients with nonischemic CMP, about double the incidence among those with ischemic heart disease(3. Mapping and ablation of these epicardial circuits is quite exigent. Although coronary veins can be used to perform epicardial mapping, the manipulation of the catheter is strictly limited to the anatomical distribution of these vessels. Thus, the subxiphoid percutaneous approach to the pericardial space is the only technique that allows extensive, unhampered mapping of the epicardial surface of both ventricles.

  17. Transcoronary ablation of septal hypertrophy compared with surgery in the treatment of hypertrophic obstructive cardiomyopathy

    姜腾勇; 吴学思; 吕强; 孟旭; 贾长琪; 张银

    2004-01-01

    @@ Transcoronary ablation of septal hypertrophy (TASH)can lead to sustained improvement in both hemodynamics and symptoms in patients with hypertrophic obstructive cardiomyopathy ( HOCM ) . 1-4 However, there have been few reports about its efficacy and safety compared with traditional surgical procedures. This study sought to compare TASH with surgery in the treatment of HOCM.

  18. Radiofrequency ablation for incidentally identified primary intrahepatic cholangiocarcinoma

    Witold Zgodzinski; N.Joseph Espat

    2005-01-01

    Cholangiocarcinoma is the second most common primary hepato-biliary malignancy. The majority of patients with primary hepatic tumors are not suitable candidates for resection, due to advanced stage of the disease at presentation, anatomic limitations and medical comorbidities. At present, radiofrequency ablation (RFA) may offer an alternative, feasible and safe therapy for selected patients with hepatic tumors, who are not otherwise candidates for hepatic resection. Herein, we present the case of successful RFA in a patient with a solitary, primary intrahepatic cholangiocarcinoma. The patient remained free of disease 24 mo after the procedure, and is still followed up. This is the first report of RFA application inthe treatment of primary intrahepatic cholangiocarcinoma.

  19. Treatment of osteoid osteoma using CT-guided radiofrequency ablation versus MR-guided laser ablation: A cost comparison

    Maurer, M.H., E-mail: martin.maurer@charite.de [Charite - Universitaetsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany); Gebauer, B., E-mail: bernhard.gebauer@charite.de [Charite - Universitaetsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany); Wieners, G., E-mail: gero.wieners@charite.de [Charite - Universitaetsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany); De Bucourt, M., E-mail: maximilian.de-bucourt@charite.de [Charite - Universitaetsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany); Renz, D.M., E-mail: diane.renz@charite.de [Charite - Universitaetsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany); Hamm, B., E-mail: bernd.hamm@charite.de [Charite - Universitaetsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany); Streitparth, F., E-mail: florian.streitparth@charite.de [Charite - Universitaetsmedizin Berlin, Department of Radiology, Augustenburger Platz 1, 13353 Berlin (Germany)

    2012-11-15

    Objective: To compare the costs of CT-guided radiofrequency ablation (RFA) and MR-guided laser ablation (LA) for minimally invasive percutaneous treatment of osteoid osteoma. Materials and methods: Between November 2005 and October 2011, 20 patients (14 males, 6 females, mean age 20.3 {+-} 9.1 years) underwent CT-guided RFA and 24 patients (18 males, 6 females; mean age, 23.8 {+-} 13.8 years) MR-guided LA (open 1.0 Tesla, Panorama HFO, Philips, Best, Netherlands) for osteoid osteoma diagnosed on the basis of clinical presentation and imaging findings. Prorated costs of equipment use (purchase, depreciation, and maintenance), staff costs, and expenditure for disposables were identified for CT-guided RFA and MR-guided LA procedures. Results: The average total costs per patient were EUR 1762 for CT-guided RFA and EUR 1417 for MR-guided LA. These were (RFA/LA) EUR 92/260 for equipment use, EUR 149/208 for staff, and EUR 870/300 for disposables. Conclusion: MR-guided LA is less expensive than CT-guided RFA for minimally invasive percutaneous ablation of osteoid osteoma. The higher costs of RFA are primarily due to the higher price of the disposable RFA probes.

  20. Maze Surgery

    ... called chronic atrial fibrillation (AF). AF is a fast, irregular heart rhythm where the upper chambers of the heart contract in an uncoordinated fashion. AF is dangerous because it may cause blood ...

  1. Possible role for cryoballoon ablation of right atrial appendage tachycardia when conventional ablation fails.

    Amasyali, Basri; Kilic, Ayhan

    2015-06-01

    Focal atrial tachycardia arising from the right atrial appendage usually responds well to radiofrequency ablation; however, successful ablation in this anatomic region can be challenging. Surgical excision of the right atrial appendage has sometimes been necessary to eliminate the tachycardia and prevent or reverse the resultant cardiomyopathy. We report the case of a 48-year-old man who had right atrial appendage tachycardia resistant to multiple attempts at ablation with use of conventional radiofrequency energy guided by means of a 3-dimensional mapping system. The condition led to cardiomyopathy in 3 months. The arrhythmia was successfully ablated with use of a 28-mm cryoballoon catheter that had originally been developed for catheter ablation of paroxysmal atrial fibrillation. To our knowledge, this is the first report of cryoballoon ablation without isolation of the right atrial appendage. It might also be an alternative to epicardial ablation or surgery when refractory atrial tachycardia originates from the right atrial appendage.

  2. Effective temperatures of polymer laser ablation

    Furzikov, Nickolay P.

    1991-09-01

    Effective temperatures of laser ablation of certain polymers are extracted from experimental dependences of ablation depths on laser fluences. Dependence of these temperatures on laser pulse durations is established. Comparison with the known thermodestruction data shows that the effective temperature corresponds to transient thermodestruction proceeding by the statistically most probable way.

  3. VUV laser ablation of polymers. Photochemical aspect

    Castex, M. C.; Bityurin, N.; Olivero, C.; Muraviov, S.; Bronnikova, N.; Riedel, D.

    2000-12-01

    A photochemical theory of laser ablation owing to the direct chain scission process is considered in quite general form taking into account the modification of material. The formulas obtained can be used for estimating mechanisms of VUV laser ablation of polymers.

  4. Therapy of HCC-radiofrequency ablation.

    Buscarini, L; Buscarini, E

    2001-01-01

    Radiofrequency interstitial hyperthermia has been used for percutaneous ablation of hepatocellular carcinoma, under ultrasound guidance in local anesthesia. Conventional needle electrodes require a mean number of 3 sessions to treat tumors of diameter hemotorax in one case; a fluid collection in the site of ablated tumor in one patient treated by combination of transcatheter arterial embolization and radiofrequency application.

  5. RADIOFREQUENCY ABLATION OF IDIOPATHIC RIGHT VENTRICULAR TACHYCARDIA

    华伟; JituVohra

    1998-01-01

    This paper presents our experieaee with radioreqencey ablation (RFA) for idiopathic ventricular tschycardia (VT) arising from right ventricle in 12 patients(pts). The age range d patients was 21~50, with a mean of 38. 5 years. Ten out of 12 were females, 1 patient had eandia failure due to almost incessant VT while the rest had normal left ventricular function.Twelve pts had VT arising from the fight ventricle; of those, 9 were from the outflow truct, 2 from the RV apex, and l from the RV inflow. In all tats the diagnostic study and therapeutic RFA were combined in a single procedure, pacemapping and local aetlvition time were used to guide the site of RFA in Ors with VT arising froth the tight ventricle.RFA was successful in 11 of the 12 pts ( 91%). Ntmaher of RF applications were 1~27, mean 9. 6; fluoroscopy time were 4~75, mean 26. 9 minutes. RFA for idiopathic RV has a high success rate. This mode of treament should be considered as a nonphartaaeologieal curative treatment for symptomatic pts.

  6. 5-HTT deficiency affects neuroplasticity and increases stress sensitivity resulting in altered spatial learning performance in the Morris water maze but not in the Barnes maze.

    Margherita M Karabeg

    Full Text Available The purpose of this study was to evaluate whether spatial hippocampus-dependent learning is affected by the serotonergic system and stress. Therefore, 5-HTT knockout (-/-, heterozygous (+/- and wildtype (+/+ mice were subjected to the Barnes maze (BM and the Morris water maze (WM, the latter being discussed as more aversive. Additionally, immediate early gene (IEG expression, hippocampal adult neurogenesis (aN, and blood plasma corticosterone were analyzed. While the performance of 5-HTT-/- mice in the BM was undistinguishable from both other genotypes, they performed worse in the WM. However, in the course of the repeated WM trials 5-HTT-/- mice advanced to wildtype level. The experience of a single trial of either the WM or the BM resulted in increased plasma corticosterone levels in all genotypes. After several trials 5-HTT-/- mice exhibited higher corticosterone concentrations compared with both other genotypes in both tests. Corticosterone levels were highest in 5-HTT-/- mice tested in the WM indicating greater aversiveness of the WM and a greater stress sensitivity of 5-HTT deficient mice. Quantitative immunohistochemistry in the hippocampus revealed increased cell counts positive for the IEG products cFos and Arc as well as for proliferation marker Ki67 and immature neuron marker NeuroD in 5-HTT-/- mice compared to 5-HTT+/+ mice, irrespective of the test. Most differences were found in the suprapyramidal blade of the dentate gyrus of the septal hippocampus. Ki67-immunohistochemistry revealed a genotype x environment interaction with 5-HTT genotype differences in naïve controls and WM experience exclusively yielding more Ki67-positive cells in 5-HTT+/+ mice. Moreover, in 5-HTT-/- mice we demonstrate that learning performance correlates with the extent of aN. Overall, higher baseline IEG expression and increased an in the hippocampus of 5-HTT-/- mice together with increased stress sensitivity may constitute the neurobiological correlate of

  7. 5-HTT deficiency affects neuroplasticity and increases stress sensitivity resulting in altered spatial learning performance in the Morris water maze but not in the Barnes maze.

    Karabeg, Margherita M; Grauthoff, Sandra; Kollert, Sina Y; Weidner, Magdalena; Heiming, Rebecca S; Jansen, Friederike; Popp, Sandy; Kaiser, Sylvia; Lesch, Klaus-Peter; Sachser, Norbert; Schmitt, Angelika G; Lewejohann, Lars

    2013-01-01

    The purpose of this study was to evaluate whether spatial hippocampus-dependent learning is affected by the serotonergic system and stress. Therefore, 5-HTT knockout (-/-), heterozygous (+/-) and wildtype (+/+) mice were subjected to the Barnes maze (BM) and the Morris water maze (WM), the latter being discussed as more aversive. Additionally, immediate early gene (IEG) expression, hippocampal adult neurogenesis (aN), and blood plasma corticosterone were analyzed. While the performance of 5-HTT-/- mice in the BM was undistinguishable from both other genotypes, they performed worse in the WM. However, in the course of the repeated WM trials 5-HTT-/- mice advanced to wildtype level. The experience of a single trial of either the WM or the BM resulted in increased plasma corticosterone levels in all genotypes. After several trials 5-HTT-/- mice exhibited higher corticosterone concentrations compared with both other genotypes in both tests. Corticosterone levels were highest in 5-HTT-/- mice tested in the WM indicating greater aversiveness of the WM and a greater stress sensitivity of 5-HTT deficient mice. Quantitative immunohistochemistry in the hippocampus revealed increased cell counts positive for the IEG products cFos and Arc as well as for proliferation marker Ki67 and immature neuron marker NeuroD in 5-HTT-/- mice compared to 5-HTT+/+ mice, irrespective of the test. Most differences were found in the suprapyramidal blade of the dentate gyrus of the septal hippocampus. Ki67-immunohistochemistry revealed a genotype x environment interaction with 5-HTT genotype differences in naïve controls and WM experience exclusively yielding more Ki67-positive cells in 5-HTT+/+ mice. Moreover, in 5-HTT-/- mice we demonstrate that learning performance correlates with the extent of aN. Overall, higher baseline IEG expression and increased an in the hippocampus of 5-HTT-/- mice together with increased stress sensitivity may constitute the neurobiological correlate of raised

  8. High Heat Flux Block Ablator-in-Honeycomb Heat Shield Using Ablator/Aerogel-Filled Foam Project

    National Aeronautics and Space Administration — Ultramet and ARA Ablatives Laboratory previously developed and demonstrated advanced foam-reinforced carbon/phenolic ablators that offer substantially increased high...

  9. The effect of sub-anesthetic and anesthetic ketamine on water maze memory acquisition, consolidation and retrieval.

    Moosavi, Maryam; Yadollahi Khales, Golnaz; Rastegar, Karim; Zarifkar, Asadollah

    2012-02-29

    Ketamine, a non-selective inhibitor of NMDA (N-methyl-D-aspartate) channels is used in anesthetic or sub-anesthetic doses to induce analgesia, amnesia, to suppress fear, anxiety and depression. Although the ketamine's effect on memory acquisition is known, its effects on other aspects of memory are controversial. Morris water maze is a task which assesses spatial learning and memory. This study was aimed to assess the ketamine's differential effect on water maze memory acquisition, consolidation and retrieval. Male Sprague-Dawley rats (250-350 g) were trained in water maze single training session. 24h later a probe trial which was consisted of a single trial without platform was done. To assess the effect of ketamine on water maze memory acquisition it was administered before training; to assess its effect on memory consolidation it was administered immediately after training and to assess its effect on memory retrieval it was injected before probe trial. Ketamine both in sub-anesthetic and anesthetic doses impaired water maze memory acquisition, its anesthetic dose but not sub-anesthetic dose impaired memory consolidation and on retrieval stage, both doses deteriorated memory retrieval. It seems that NMDA receptor activity is not just necessary during water maze memory acquisition but also their post-learning reactivation is required to maintain memory consolidation and retrieval.

  10. Imaging Features of Radiofrequency Ablation with Heat-Deployed Liposomal Doxorubicin in Hepatic Tumors

    Hong, Cheng William, E-mail: williamhongcheng@gmail.com; Chow, Lucy, E-mail: lucychow282@gmail.com [National Institutes of Health, Center for Interventional Oncology, Clinical Center (United States); Turkbey, Evrim B., E-mail: evrimbengi@yahoo.com [National Institutes of Health, Radiology and Imaging Sciences, Clinical Center (United States); Lencioni, Riccardo, E-mail: riccardo.lencioni@med.unipi.it [Pisa University Hospital, Division of Diagnostic Imaging and Intervention, Department of Hepatology and Liver Transplantation (Italy); Libutti, Steven K., E-mail: slibutti@montefiore.org [Albert Einstein College of Medicine, Montefiore-Einstein Center for Cancer Care, Department of Surgery (United States); Wood, Bradford J., E-mail: bwood@nih.gov [National Institutes of Health, Center for Interventional Oncology, Clinical Center (United States)

    2016-03-15

    IntroductionThe imaging features of unresectable hepatic malignancies in patients who underwent radiofrequency ablation (RFA) in combination with lyso-thermosensitive liposomal doxorubicin (LTLD) were determined.Materials and MethodsA phase I dose escalation study combining RFA with LTLD was performed with peri- and post- procedural CT and MRI. Imaging features were analyzed and measured in terms of ablative zone size and surrounding penumbra size. The dynamic imaging appearance was described qualitatively immediately following the procedure and at 1-month follow-up. The control group receiving liver RFA without LTLD was compared to the study group in terms of imaging features and post-ablative zone size dynamics at follow-up.ResultsPost-treatment scans of hepatic lesions treated with RFA and LTLD have distinctive imaging characteristics when compared to those treated with RFA alone. The addition of LTLD resulted in a regular or smooth enhancing rim on T1W MRI which often correlated with increased attenuation on CT. The LTLD-treated ablation zones were stable or enlarged at follow-up four weeks later in 69 % of study subjects as opposed to conventional RFA where the ablation zone underwent involution compared to imaging acquired immediately after the procedure.ConclusionThe imaging features following RFA with LTLD were different from those after standard RFA and can mimic residual or recurrent tumor. Knowledge of the subtle findings between the two groups can help avoid misinterpretation and proper identification of treatment failure in this setting. Increased size of the LTLD-treated ablation zone after RFA suggests the ongoing drug-induced biological effects.

  11. Real-time tumor ablation simulation based on the dynamic mode decomposition method

    Bourantas, George C.

    2014-05-01

    Purpose: The dynamic mode decomposition (DMD) method is used to provide a reliable forecasting of tumor ablation treatment simulation in real time, which is quite needed in medical practice. To achieve this, an extended Pennes bioheat model must be employed, taking into account both the water evaporation phenomenon and the tissue damage during tumor ablation. Methods: A meshless point collocation solver is used for the numerical solution of the governing equations. The results obtained are used by the DMD method for forecasting the numerical solution faster than the meshless solver. The procedure is first validated against analytical and numerical predictions for simple problems. The DMD method is then applied to three-dimensional simulations that involve modeling of tumor ablation and account for metabolic heat generation, blood perfusion, and heat ablation using realistic values for the various parameters. Results: The present method offers very fast numerical solution to bioheat transfer, which is of clinical significance in medical practice. It also sidesteps the mathematical treatment of boundaries between tumor and healthy tissue, which is usually a tedious procedure with some inevitable degree of approximation. The DMD method provides excellent predictions of the temperature profile in tumors and in the healthy parts of the tissue, for linear and nonlinear thermal properties of the tissue. Conclusions: The low computational cost renders the use of DMD suitable forin situ real time tumor ablation simulations without sacrificing accuracy. In such a way, the tumor ablation treatment planning is feasible using just a personal computer thanks to the simplicity of the numerical procedure used. The geometrical data can be provided directly by medical image modalities used in everyday practice. © 2014 American Association of Physicists in Medicine.

  12. Femtosecond ablation of ultrahard materials

    Dumitru, G.; Romano, V.; Weber, H. P.; Sentis, M.; Marine, W.

    Several ultrahard materials and coatings of definite interest for tribological applications were tested with respect to their response when irradiated with fs laser pulses. Results on cemented tungsten carbide and on titanium carbonitride are reported for the first time and compared with outcomes of investigations on diamond and titanium nitride. The experiments were carried out in air, in a regime of 5-8 J/cm2 fluences, using the beam of a commercial Ti:sapphire laser. The changes induced in the surface morphology were analysed with a Nomarski optical microscope, and with SEM and AFM techniques. From the experimental data and from the calculated incident energy density distributions, the damage and ablation threshold values were determined. As expected, the diamond showed the highest threshold, while the cemented tungsten carbide exhibited typical values for metallic surfaces. The ablation rates determined (under the above-mentioned experimental conditions) were in the range 0.1-0.2 μm per pulse for all the materials investigated.

  13. Interventional procedures in the chest.

    Vollmer Torrubiano, I; Sánchez González, M

    2016-05-01

    Many thoracic conditions will require an interventional procedure for diagnosis and/or treatment. For this reason, radiologists need to know the indications and the technique for each procedure. In this article, we review the various interventional procedures that radiologists should know and the indications for each procedure. We place special emphasis on the potential differences in the diagnostic results and complications between fine-needle aspiration and biopsy. We also discuss the indications for radiofrequency ablation of lung tumors and review the concepts related to the drainage of pulmonary abscesses. We devote special attention to the management of pleural effusion, covering the indications for thoracocentesis and when to use imaging guidance, and to the protocol for pleural drainage. We also discuss the indications for percutaneous treatment of pericardial effusion and the possible complications of this treatment. Finally, we discuss the interventional management of mediastinal lesions and provide practical advice about how to approach these lesions to avoid serious complications.

  14. Increased resting heart rate following radiofrequency catheter ablation for atrial fibrillation

    Nilsson, Brian; Chen, Xu; Pehrson, Steen;

    2005-01-01

    the procedure. RESULTS: Following PV isolation, the mean HR significantly increased from 58 +/- 10 bpm at baseline to 67 +/- 12 bpm at one month, 71 +/- 13 bpm at three months, 69 +/- 12 bpm at six months, 69 +/- 13 at nine months, and 70 +/- 13 at 12 months follow-up. The ablation success significantly...... correlated with the increase in HR at one month follow-up. In three patients the mean HR increased > 25 bpm resulting in symptoms necessitating therapy with rate-controlling drugs. CONCLUSION: PV isolation in patients with AF may result in increased HR, which positively correlated with the ablation success...

  15. Radiofrequency thermal ablation (RFA) of liver tumors: open surgical or percutaneous approach?

    Crucitti, A; Danza, F M; Pirulli, P G V; Antinori, A; Antonacci, V; La Greca, A; Bock, E; Magistrelli, P

    2004-11-01

    RFA was used to ablate 81 liver lesions: 61 liver metastases and 20 hepatomas. An open surgical approach was adopted in 19 instances (27.5%), 12 of which were simultaneously treated for associated diseases, and percutaneous treatment was adopted in 50 instances (72.5%). The CT liver control at 6 months showed a complete necrosis in 50 lesions (66.3%). The advantages of the percutaneous approach include less invasiveness, reduced postoperative pain, shorter hospitalization, reduced costs and less discomfort in repeating the procedure. In conclusion, radiofrequency liver nodule ablation could be considered, today, as one of the promising and versatile techniques for loco-regional liver cancer control.

  16. Osteoid Osteoma with a Multicentric Nidus: Interstitial Laser Ablation under MRI Guidance

    David Kaul

    2013-01-01

    Full Text Available Osteoid osteoma (OO is a common benign tumor of the bone and is typically treated by thermal ablation with computed tomography (CT guidance. Only a few cases of multicentric OO have been described. We here report the case of an 11-year-old boy with multicentric OO of the right femur treated with laser ablation under open high-field MRI guidance. The steps of the interventional MRI procedure are described, discussing the benefits and disadvantages of MRI versus CT guidance especially with regard to younger patients.

  17. History and Technical Approaches and Considerations for Ablative Surgery for Epilepsy.

    Sinha, Saurabh; Danish, Shabbar F

    2016-01-01

    The history of epilepsy surgery is generally noted to have begun in 1886 with Victor Horsley's first report of craniotomies for posttraumatic epilepsy. With increased understanding of brain function and development of electroencephalographic methods, nonlesional epilepsy began to be treated with resection in the 1950s. Methodological improvements and increased understanding of pathophysiology followed, and the advent of stereotaxy and ablative technology in the 1960s and 1970s heralded a new era of minimally invasive, targeted procedures for lesional and nonlesional epilepsy. Current techniques combine stereotactic methods, improved ablative technologies, and electroencephalographic methods for a multidisciplinary approach to the neurosurgical treatment of epilepsy.

  18. Right phrenic injury after radiofrequency catheter ablation of atrial tachycardia at crista terminalis

    JIA Yu-he; WANG Fang-zheng; GAO Dong-sheng; CHU Jian-min; PU Jie-ling; REN Xiao-qing; HUA Wei; ZHANG Shu

    2011-01-01

    A 62-year-old woman with frequent occurrence of symptomatic atrial tachycardia with a foci located at the root of the upper crista terminalis was found to have right diaphragm paresis after receiving a total of 8 radiofrequency energy deliveries (40-60 W, 50-60℃) and a total duration of 540 seconds of ablation therapy (7Fr 8 mm deflectable ablation catheter). The right diaphragm paresis remained resolved up to 14 months after the procedure as confirmed by repeated chest X-rays.

  19. Radiofrequency ablation of hepatocellular carcinoma located in the liver dome under intermittent CT fluoroscopy guidance

    Park, Darlene; Cho, Yun Ku; Cho, Hyun Je; KIm, Mi Young [Dept. of Radiology, VHS Medical Center, Seoul (Korea, Republic of)

    2014-02-15

    To evaluate the clinical effectiveness of an intermittent computed tomography (CT) fluoroscopy-guided radiofrequency (RF) ablation of hepatocellular carcinoma located in the liver dome. Between 2005 and 2010 23 patients with hepatocellular carcinoma (HCC) nodules located in the liver dome underwent an intermittent CT fluoroscopy-guided RF ablation. The primary endpoint was the local tumor progression. Procedure-related complications occurred in 3 of 23 patients. To evaluate the prognostic factors for the local tumor progression, univariate and multivariate analyses were performed using the Cox proportional hazards model. The chi-squared test was performed to evaluate the association of access route and procedure-related complication. The study was approved by the Institutional Review Board of our hospital. The Tumor sizes ranged between 1.0 and 2.9 cm. An initial complete ablation was achieved in all patients. The median follow-up period was 31 months and the major complication rate was 4.3%. The cumulative rate of local tumor progression at 3 years was 20%. The univariate analysis revealed that only serum total bilirubin level (p = 0.048) and prior chemoembolization were statistically significant (p = 0.044), but there was no independently significant prognostic factor on multivariate analysis. Procedure-related complications occurred in 3 of 23 patients. For HCC located in the liver dome an intermittent CT fluoroscopy-guided RF ablation could be performed safely and effectively.

  20. Ten-year literature review of global endometrial ablation with the NovaSure® device

    Gimpelson RJ

    2014-03-01

    Full Text Available Richard J Gimpelson Mercy Clinic, Minimally Invasive Gynecology, Department of Obstetrics and Gynecology, Mercy Hospital St Louis, St Louis, MO, USA Abstract: This review examines the peer-reviewed literature describing prospective studies that report amenorrhea rates, patient satisfaction, and surgical reintervention rates following the NovaSure® endometrial ablation procedure. A search of the English-language literature published from 2000 to 2011 was conducted using PubMed. Ten prospective studies, six single-arm NovaSure trials, and four randomized controlled trials comparing the NovaSure procedure with other global endometrial ablation modalities met the inclusion criteria and were reviewed. The follow-up periods ranged from 6 to 60 months. Amenorrhea rates for the NovaSure procedure ranged from 30.0% to 75.0%. Patients who reported being satisfied with the NovaSure procedure ranged from 85.0% to 94.0%. In randomized controlled trials with other global endometrial ablation modalities, amenorrhea rates at 12 months with the NovaSure procedure ranged from 43.0% to 56.0%, while other modalities ranged from 8% to 24%. In addition, this manuscript reviews the following: the NovaSure technology; use of the NovaSure procedure in the office setting; intraoperative and postoperative pain; effects on premenstrual syndrome (PMS; dysmenorrhea; special circumstances, including presence of uterine disease, history of cesarean delivery, coagulopathy, or use of anticoagulant medication; post-procedure uterine cavity assessment and cancer risk; contraception and pregnancy; and safety. Keywords: abnormal uterine bleeding, menorrhagia, endometrial ablation, NovaSure®

  1. Behavioral profiles displayed by rats in an elevated asymmetric plus-maze: effects of diazepam

    Ruarte M.B.

    1999-01-01

    Full Text Available When rats are exposed to unknown environments where novelty and fear-inducing characteristics are present (conflictive environments, some specific behaviors are induced and exploration is apparently modulated by fear. In our laboratory, a new type of plus-maze was designed as a model of conflictive exploration. The maze is composed of four arms with different geometrical characteristics, differing from each other by the presence or absence of walls. The degree of asymmetry was as follows: NW, no wall arm; SW, a single high wall present; HL, a low and a high wall present, and HH, two high walls present. The four arms were arranged at 90o angles and the apparatus was called the elevated asymmetric plus-maze (APM. The purpose of the present study was to assess the behavioral profile of rats exposed for a single time to the APM with or without treatment with benzodiazepine. Increasing doses of diazepam were injected intraperitoneally in several groups of male, 90-day-old Holtzman rats. Distilled water was injected in control animals. Thirty minutes after treatment all rats were exposed singly to a 5-min test in the APM. Diazepam induced a biphasic modification of exploration in the NW and SW arms. The increase in the exploration score was evident at low doses of diazepam (0.25-1.0 mg/kg body weight and the decrease in exploration was found with the higher doses of diazepam (2.0-3.0 mg/kg body weight. Non-exploratory behaviors (permanency were not affected by benzodiazepine treatment. In the HL arm, exploration was not modified but permanency was increased in a dose-dependent manner. In the HH arm, exploration and permanency were not affected. Results are compatible with the idea that exploration-processing mechanisms in conflictive environments are modulated by fear-processing mechanisms of the brain.

  2. Individual differences in the elevated plus-maze and the forced swim test.

    Estanislau, Celio; Ramos, Anna Carolina; Ferraresi, Paula Daniele; Costa, Naiara Fernanda; de Carvalho, Heloisa Maria Cotta Pires; Batistela, Silmara

    2011-01-01

    The elevated plus-maze is an apparatus composed of enclosed and open (elevated) arms and time spent in the open arms by a rat can be increased/decreased by anxiolytic/anxiogenic agents. In the forced swim test, floating behavior is used as an index of behavioral despair and can be decreased by antidepressant agents. As the comorbidity between anxiety and depression is a remarkable issue in human behavioral disorders, a possible relationship between the behaviors seen in the cited tests is of great relevance. In the present study, fifty-four male rats (Rattus norvegicus) were submitted to a plus-maze session and to a 2-day forced swim protocol. According to their time in the open arms, they were divided into three groups: Low Open, Medium Open and High Open. Some plus-maze measures were found to be coherent with time in the open arms and are suggested to also be reliable anxiety indexes. In the forced swim test, the Low Open group showed decreases in floating duration from forced swim Session 1 to Session 2, an alteration opposite to that observed in the other groups (particularly, the Medium Open group). The Low Open group also showed increases in floating latency, again in sharp contrast with the alteration found in the other groups. Accordingly, positive and negative correlation were found between time in the open arms and floating duration and latency, respectively. Results are compared to previous studies and mediation of the effect by reactivity to aversive stimulation or alterations induced by open arm exposure is discussed.

  3. Mazes and meso-islands: Impact of Ag preadsorption on Ge growth on Si(111)

    Schmidt, Th.; Speckmann, M.; Flege, J. I.; Müller-Caspary, K.; Heidmann, I.; Kubelka-Lange, A.; Menteş, T. O.; Niño, M. Á.; Locatelli, A.; Rosenauer, A.; Falta, J.

    2016-12-01

    The preadsorption of Ag on Si(111) drastically changes the growth of Ge. In a temperature range from 400°C to 650°C, Ag adsorption on Si leads to the formation of a √{3 }×√{3 } -R 30° reconstruction that exhibits a maze-like morphology on the mesoscopic scale, as observed by low-energy electron diffraction (LEED) and low-energy electron microscopy. This maze morphology can be attributed to a surface roughening on an atomic scale, induced by the re-arrangement of top layer atoms during the 7 ×7 to √{3 }×√{3 } -R 30° transition. The subsequent deposition of Ge results in the formation of a wetting layer, the evolution of which has been found to be governed by the Ag/Si(111)-√{3 }×√{3 } -R 30° template's maze structure, as the latter offers a high density of heterogeneous nucleation sites. Upon further Ge growth, three-dimensional islands with diameters in the micrometer range are formed, which exhibit a large and flat (111) top facet. X-ray photoemission electron microscopy reveals that during Ge growth, Ag is segregating to the surface very efficiently. Grazing-incidence x-ray diffraction and transmission electron microscopy have been used to study the composition, strain state and defect structure of the Ge islands in dependence of the growth temperature. The strain induced by lattice mismatch is found to be largely relaxed (80-90% relaxation) in the investigated growth temperature range from 400 to 600°C, which is confirmed by high-resolution LEED measurements. As a main relaxation mechanism, the formation of interfacial misfit dislocations has been identified. Interdiffusion of Si into the Ge islands becomes more and more pronounced for increasing growth temperature, whereas the formation of twinned Ge regions can drastically be suppressed at higher temperature.

  4. Temporal structure of the rat's behavior in elevated plus maze test.

    Casarrubea, M; Roy, V; Sorbera, F; Magnusson, M S; Santangelo, A; Arabo, A; Crescimanno, G

    2013-01-15

    Aim of the research was to evaluate, by means of quantitative and multivariate temporal pattern analyses, the behavior of Wistar rat in elevated plus maze (EPM) test. On the basis of an ethogram encompassing 24 behavioral elements, quantitative results showed that 130.14 ± 8.01 behavioral elements occurred in central platform and in closed arms (protected zones), whereas 88.62 ± 6.04 occurred in open arms (unprotected zones). Percent distribution was characterized by a prevalence of sniffing, walking and vertical exploration. Analysis of minute-by-minute duration evidenced a decrease for time spent in open arms and central platform and an increase for time spent in closed arms. As to multivariate t-pattern analysis, 126 different temporal patterns were detected. Behavioral stripes, summarizing distribution of such t-patterns along time, showed that several t-patterns were not homogeneously distributed along the test observational period: t-patterns encompassing behavioral events occurring prevalently in central platform-open arms were observed during the first minutes, whereas t-patterns structured on the basis of events occurring mainly in central platform-closed arms were detected during the last minutes. Therefore, during the observation in elevated plus maze, rat's behavior undergoes significant rearrangements of its temporal features. Present research demonstrates, for the first time, the existence of complex and significantly timed behavioral sequences in the activity of Wistar rats tested in elevated plus maze. Application of t-pattern analysis can provide useful tools to characterize the behavioral dynamics of anxiety-related rodent behavior and differentiate the effect of various anxioselective substances.

  5. Analysis of infrared laser tissue ablation

    McKenzie, Gordon P.; Timmerman, Brenda H.; Bryanston-Cross, Peter J.

    2005-04-01

    The mechanisms involved in infrared laser tissue ablation are studied using a free electron laser (FELIX) in order to clarify whether the increased ablation efficiency reported in literature for certain infrared wavelengths is due to a wavelength effect or to the specific pulse structure of the lasers that are generally used in these studies. Investigations are presented of ablation of vitreous from pigs" eyes using several techniques including protein gel electrophoresis and ablation plume visualization. The ablation effects of three different infrared wavelengths are compared: 3 mm, which is currently in clinical surgical use, and the wavelengths associated with the amide I and amide II bands, i.e. 6.2 mm and 6.45mm, respectively. The results suggest a different ablation mechanism to be in operation for each studied wavelength, thus indicating that the generally reported increased ablation efficiency in the 6-6.5 micron range is due to the wavelength rather than the typical free electron laser pulse structure.

  6. Effects of histamine on MK-801-induced memory deficits in radial maze performance in rats.

    Chen, Z; Zhao, Q; Sugimoto, Y; Fujii, Y; Kamei, C

    1999-08-21

    The effects of histamine on the spatial memory deficits induced by MK-801 were investigated using the eight-arm radial maze paradigm in rats. Intracerebroventricular (i.c.v.) injection of histamine or thioperamide, and intraperitoneal (i.p.) injection of histidine improved the spatial memory deficits induced by MK-801. Similar results were obtained with 2-thiazolylethylamine. In contrast, 4-methylhistamine showed no significant effect. Based on these observations, it seems likely that the protective effect of histamine on MK-801-induced spatial memory deficit is mediated by H(1)-receptors.

  7. Microglial ablation and lipopolysaccharide preconditioning affects pilocarpine-induced seizures in mice

    Mirrione, M.M.; Mirrione, M.M.; Konomosa, D.K.; Ioradanis, G.; Dewey, S.L.; Agzzid, A.; Heppnerd, F.L.; Tsirka, St.E.

    2010-04-01

    Activated microglia have been associated with neurodegeneration in patients and in animal models of Temporal Lobe Epilepsy (TLE), however their precise functions as neurotoxic or neuroprotective is a topic of significant investigation. To explore this, we examined the effects of pilocarpine-induced seizures in transgenic mice where microglia/macrophages were conditionally ablated. We found that unilateral ablation of microglia from the dorsal hippocampus did not alter acute seizure sensitivity. However, when this procedure was coupled with lipopolysaccharide (LPS) preconditioning (1 mg/kg given 24 h prior to acute seizure), we observed a significant pro-convulsant phenomenon. This effect was associated with lower metabolic activation in the ipsilateral hippocampus during acute seizures, and could be attributed to activity in the mossy fiber pathway. These findings reveal that preconditioning with LPS 24 h prior to seizure induction may have a protective effect which is abolished by unilateral hippocampal microglia/macrophage ablation.

  8. Endoscopic ultrasound-guided ethanol ablation ofpancreatic neuroendocrine tumours: A case study andliterature review

    2016-01-01

    Here we offer a review of the literature regardingendoscopic ultrasound-guided ethanol ablation forpancreatic neuroendocrine tumours and describe thecase of a cystic tumour completely ablated after amultisession procedure. A total of 35 PubMed indexedcases of treated functioning and non-functioningpancreatic neuroendocrinetumours resulted fromour search, 29 of which are well-documented andsummarised. Endoscopic ultrasound-guided ethanolablation appears as a local, minimallyinvasive treatmentof pancreatic neuroendocrinetumours, suitable forselected patients. This techniqueappears feasible,relatively safe and efficient, especiallywhen applied tosymptom relief in functioning tumours, aiming at loss ofendocrine secretion. For non-functioning tumours, wherethe goal is complete tissue ablation, eus guided ethanolablation can provide good results for patients whoare unfit for surgery or for those who refuse surgicalresection. Its role in "fit for surgery" patients requiresassessment through further studies.

  9. Acute myocardial infarction after radiofrequency catheter ablation of typical atrial flutter.

    Yune, Sehyo; Lee, Woo Joo; Hwang, Ji-won; Kim, Eun; Ha, Jung Min; Kim, June Soo

    2014-02-01

    A 53-yr-old man underwent radiofrequency ablation to treat persistent atrial flutter. After the procedure, the chest pain was getting worse, and the electrocardiogram showed ST-segment elevation in inferior leads with reciprocal changes. Immediate coronary angiography showed total occlusion with thrombi at the distal portion of the right coronary artery, which was very close to the ablation site. Intervention with thrombus aspiration and balloon dilatation was successful, and the patient recovered without any kind of sequelae. Although the exact mechanism is obscure, the most likely explanation is a thermal injury to the vascular wall that ruptured into the lumen and formed thrombus. Vasospasm and thromboembolism can also be other possibilities. This case raise the alarm to cardiologists who perform radiofrequency ablation to treat various kinds of cardiac arrhythmias, in that myocardial infarction has been rarely considered one of the complications.

  10. Post-training Inactivation of the Anterior Thalamic Nuclei Impairs Spatial Performance on the Radial Arm Maze

    Harvey, Ryan E.; Thompson, Shannon M.; Sanchez, Lilliana M.; Yoder, Ryan M.; Clark, Benjamin J.

    2017-01-01

    The limbic thalamus, specifically the anterior thalamic nuclei (ATN), contains brain signals including that of head direction cells, which fire as a function of an animal's directional orientation in an environment. Recent work has suggested that this directional orientation information stemming from the ATN contributes to the generation of hippocampal and parahippocampal spatial representations, and may contribute to the establishment of unique spatial representations in radially oriented tasks such as the radial arm maze. While previous studies have shown that ATN lesions can impair spatial working memory performance in the radial maze, little work has been done to investigate spatial reference memory in a discrimination task variant. Further, while previous studies have shown that ATN lesions can impair performance in the radial maze, these studies produced the ATN lesions prior to training. It is therefore unclear whether the ATN lesions disrupted acquisition or retention of radial maze performance. Here, we tested the role of ATN signaling in a previously learned spatial discrimination task on a radial arm maze. Rats were first trained to asymptotic levels in a task in which two maze arms were consistently baited across training. After 24 h, animals received muscimol inactivation of the ATN before a 4 trial probe test. We report impairments in post-inactivation trials, suggesting that signals from the ATN modulate the use of a previously acquired spatial discrimination in the radial-arm maze. The results are discussed in relation to the thalamo-cortical limbic circuits involved in spatial information processing, with an emphasis on the head direction signal. PMID:28321178

  11. 2-Methyl-6-(phenylethynyl pyridine (MPEP reverses maze learning and PSD-95 deficits in Fmr1 knock-out mice.

    Réno Michelle Gandhi

    2014-03-01

    Full Text Available Fragile X syndrome (FXS is caused by the lack of expression of the fragile X mental retardation protein (FMRP, which results in intellectual disability and other debilitating symptoms including impairment of visual-spatial functioning. FXS is the only single-gene disorder that is highly co-morbid with autism spectrum disorder and can therefore provide insight into its pathophysiology. Lack of FMRP results in altered group I metabotropic glutamate receptor (mGluR signalling, which is a target for putative treatments. The Hebb-Williams (H-W mazes are a set of increasingly complex spatial navigation problems that depend on intact hippocampal and thus mGluR-5 functioning. In the present investigation, we examined whether an antagonist of mGluR-5 would reverse previously described behavioural deficits in Fmr1 KO mice. Mice were trained on a subset of the H-W mazes and then treated with either 20 mg/kg of an mGluR-5 antagonist, 2-Methyl-6-(phenylethynyl pyridine (MPEP; n = 11 or an equivalent dose of saline (n = 11 prior to running test mazes. Latency and errors were dependent variables recorded during the test phase. Immediately after completing each test, marble-burying behavior was assessed which confirmed that the drug treatment was pharmacologically active during maze learning. Although latency was not statistically different between the groups, MPEP treated Fmr1 KO mice made significantly fewer errors on mazes deemed more difficult suggesting a reversal of the behavioural deficit. MPEP treated mice were also less perseverative and impulsive when navigating mazes. Furthermore, MPEP treatment reversed PSD-95 protein deficits in Fmr1 KO treated mice, whereas levels of a control protein (β-tubulin remained unchanged. These data further validate MPEP as a potentially beneficial treatment for FXS. Our findings also suggest that adapted H-W mazes may be a useful tool to document alterations in behavioural functioning following pharmacological

  12. 3D ablation catheter localisation using individual C-arm x-ray projections

    Haase, C.; Schäfer, D.; Dössel, O.; Grass, M.

    2014-11-01

    Cardiac ablation procedures during electrophysiology interventions are performed under x-ray guidance with a C-arm imaging system. Some procedures require catheter navigation in complex anatomies like the left atrium. Navigation aids like 3D road maps and external tracking systems may be used to facilitate catheter navigation. As an alternative to external tracking a fully automatic method is presented here that enables the calculation of the 3D location of the ablation catheter from individual 2D x-ray projections. The method registers a high resolution, deformable 3D attenuation model of the catheter to a 2D x-ray projection. The 3D localization is based on the divergent beam projection of the catheter. On an individual projection, the catheter tip is detected in 2D by image filtering and a template matching method. The deformable 3D catheter model is adapted using the projection geometry provided by the C-arm system and 2D similarity measures for an accurate 2D/3D registration. Prior to the tracking and registration procedure, the deformable 3D attenuation model is automatically extracted from a separate 3D cone beam CT reconstruction of the device. The method can hence be applied to various cardiac ablation catheters. In a simulation study of a virtual ablation procedure with realistic background, noise, scatter and motion blur an average 3D registration accuracy of 3.8 mm is reached for the catheter tip. In this study four different types of ablation catheters were used. Experiments using measured C-arm fluoroscopy projections of a catheter in a RSD phantom deliver an average 3D accuracy of 4.5 mm.

  13. Radiofrequency catheter ablation of atrial tachycardias related to myocardial scar or incision

    Jianqiang HU; Jiang CAO; Shengqiang WANG; Yongwen QIN; Bingyan ZHOU

    2006-01-01

    Intra-atrial re-entrant tachycardias (IARTs) are common late after heart surgery. Conventional mapping and ablation is relatively difficult because of the complicated anatomy and multiple potential re-entry loops. In this study we aimed to evaluate the electrophysiological characteristics and radiofrequency catheter ablation of atrial tachycardia (AT) induced by myocardial scar or incision. Methods In 6 patients (three male and three female, aged 33.3+ 11.8 years) who had AT related to myocardial scar or incision,electrophysiological study and radiofrequency catheter ablation (RFCA) were performed. Earliest activation combined with entrainment mapping was adopted to determine a critical isthmus. Results Re-entry related to the lateral atriotomy scar was inducible in 5 of6 patients. With entrainment mapping, the PPI (post-pacing interval)-TCL (tachycardia cycle length) difference was <30 ms when pacing at the inferior margins of the right lateral atriotomy scar. Among them, 3 patients had successful linear ablation between scar area to inferior vena cava, and 2 patients between scar area to tricuspid annulus. Re-entry involving an ASD patch was demonstrated in 1 of 6 patients. PPI-TCL differences <30 ms were observed when entraining tachycardia at sites near the septal patch. But linear ablation failed in terminating AT. There was no complication during procedure. No recurrence of AT related to incision was observed during follow-up except for the failed patient. Conclusion Under conventional electrophysiological mapping, adopting linear ablation from scar area to anatomic barrier, successful ablation can be obtained in patients with IRATs related to myocardial scar or incision.

  14. Ablation response testing of aerospace power supplies

    Lutz, S. A.; Chan, C. C.

    1993-01-01

    An experimental program was performed to assess the aerothermal ablation response of aerospace power supplies. Full-scale General Purpose Heat Source (GPHS) test articles, Graphite Impact Shell (GIS) test articles, and Lightweight Radioisotope Heater Unit (LWRHU) test articles were all tested without nuclear fuel in simulated reentry environments at the NASA Ames Research Center. Stagnation heating, stagnation pressure, stagnation surface temperature, stagnation surface recession profile, and weight loss measurements were obtained for diffusion-limited and sublimation ablation conditions. The recession profile and weight loss measurements showed an effect of surface features on the stagnation face. The surface features altered the local heating which in turn affected the local ablation.

  15. UV Laser Ablation of Electronically Conductive Polymers

    1992-06-16

    deionized water. The polymerization solution for polyaniline was prepared by mixing equal volumes of a solution that was 0.25 M in ammonium persulfate with a...rum2,0 vvcsL) TbeUV.layer ablation of thin polypyrrole and polyaniline films coated on an insulating substrate is described. UV laser ablation is used to...11liiii929. 6 1 2:- A ABSTRACT The UV laser ablation of thin polypyrrole and polyaniline films coated on an insulating substrate is described. UV laser

  16. Diamond Ablators for Inertial Confinement Fusion

    Biener, J; Mirkarimi, P B; Tringe, J W; Baker, S L; Wang, Y M; Kucheyev, S O; Teslich, N E; Wu, K J; Hamza, A V; Wild, C; Woerner, E; Koidl, P; Bruehne, K; Fecht, H

    2005-06-21

    Diamond has a unique combination of physical properties for the inertial confinement fusion ablator application, such as appropriate optical properties, high atomic density, high yield strength, and high thermal conductivity. Here, we present a feasible concept to fabricate diamond ablator shells. The fabrication of diamond capsules is a multi-step process, which involves diamond chemical vapor deposition on silicon mandrels followed by polishing, microfabrication of holes, and removing of the silicon mandrel by an etch process. We also discuss the pros and cons of coarse-grained optical quality and nanocrystalline chemical vapor deposition diamond films for the ablator application.

  17. Bipolar radiofrequency ablation of benign thyroid nodules using a multiple overlapping shot technique in a 3-month follow-up.

    Kohlhase, Konstantin David; Korkusuz, Yücel; Gröner, Daniel; Erbelding, Christian; Happel, Christian; Luboldt, Wolfgang; Grünwald, Frank

    2016-08-01

    Purpose The aim of this study was to evaluate the decrease of benign thyroid nodules after bipolar radiofrequency ablation (RFA) in a 3-month follow-up using a multiple overlapping shot technique ('MOST'). Methods A total of 18 patients with 20 symptomatic benign thyroid nodules (17 cold nodules, 3 hyperfunctioning nodules) were treated in one single session by bipolar RFA. Bipolar ablation was performed using MOST. The nodule volumes were measured prior to ablation and 3 months after the procedure using ultrasound. The population consisted of either solid (>80% solid tissue within the volume of interest), complex, or cystic nodules (thermoablative technique to treat benign thyroid nodules. Combined with the multiple overlapping shot technique it allows sufficient ablation.

  18. Robotic magnetic navigation for ablation of human arrhythmias

    Da Costa, Antoine; Guichard, Jean Baptiste; Roméyer-Bouchard, Cécile; Gerbay, Antoine; Isaaz, Karl

    2016-01-01

    Radiofrequency treatment represents the first choice of treatment for arrhythmias, in particular complex arrhythmias and especially atrial fibrillation, due to the greater benefit/risk ratio compared to antiarrhythmic drugs. However, complex arrhythmias such as atrial fibrillation require long procedures with additional risks such as X-ray exposure or serious complications such as tamponade. Given this context, the treatment of arrhythmias using robotic magnetic navigation entails a technique well suited to complex arrhythmias on account of its efficacy, reliability, significant reduction in X-ray exposure for both patient and operator, as well as a very low risk of perforation. As ongoing developments will likely improve results and procedure times, this technology will become one of the most modern technologies for treating arrhythmias. Based on the literature, this review summarizes the advantages and limitations of robotic magnetic navigation for ablation of human arrhythmias. PMID:27698569

  19. Strategies for the analysis of coal by laser ablation inductively coupled plasma mass spectroscopy.

    Kleiber, L; Fink, H; Niessner, R; Panne, U

    2002-09-01

    The potential of laser ablation inductively coupled mass spectrometry (LA-ICP-MS) was investigated for the inorganic characterization of different coal samples pressed into pellets. Reference analysis was performed by microwave-assisted digestion of the ground samples followed by ICP-MS analysis of the resulting solutions. Two different laser ablation sampling procedures were compared. For continuous sampling, three sites of the pellet were sampled for approximately one minute, whereas for sequential sampling 15 sites were sampled for two seconds, respectively. The qualitative results of the two procedures were equivalent, but continuous sampling allowed faster analysis and better precision (RSD about 10%) than sequential sampling (RSD 10-20%). Different normalization procedures with internal and extrinsic standards were investigated and allowed a quantitative determination of Al, Ti, Zn, Ni, and V with measurement uncertainties below 10% and Fe, Si, and Sn with measurement uncertainties below 20%.

  20. Strategies for the analysis of coal by laser ablation inductively coupled plasma mass spectroscopy

    Kleiber, L.; Fink, H.; Niessner, R.; Panne, U. [Institute of Hydrochemistry, Technical University of Munich, Marchioninistr. 17, 81377 Munich (Germany)

    2002-09-01

    The potential of laser ablation inductively coupled mass spectrometry (LA-ICP-MS) was investigated for the inorganic characterization of different coal samples pressed into pellets. Reference analysis was performed by microwave-assisted digestion of the ground samples followed by ICP-MS analysis of the resulting solutions. Two different laser ablation sampling procedures were compared. For continuous sampling, three sites of the pellet were sampled for approximately one minute, whereas for sequential sampling 15 sites were sampled for two seconds, respectively. The qualitative results of the two procedures were equivalent, but continuous sampling allowed faster analysis and better precision (RSD about 10%) than sequential sampling (RSD 10-20%). Different normalization procedures with internal and extrinsic standards were investigated and allowed a quantitative determination of Al, Ti, Zn, Ni, and V with measurement uncertainties below 10% and Fe, Si, and Sn with measurement uncertainties below 20%. (orig.)

  1. MRI-guided percutaneous laser ablation of small renal cell carcinoma: Initial clinical experience

    Kariniemi, Juho; Ojala, Risto; Hellstroem, Pekka; Sequeiros, Roberto Blanco (Dept. of Radiology, Dept. of Surgery, Oulu Univ. Hospital, Oulu (Finland)), e-mail: juho.kariniemi@oulu.fi

    2010-05-15

    Background: The number of detected small renal cell carcinomas (RCCs) has been rising, largely due to advances in imaging. Open surgical resection is the standard management of small RCCs; however, imaging-guided percutaneous ablative therapies have emerged as a minimally invasive treatment alternative, especially for patients who are poor candidates for surgery. Purpose: To evaluate the initial clinical experience of magnetic resonance imaging (MRI)-guided percutaneous laser ablation of small RCCs. Material and Methods: Eight patients with 10 tumors were treated with percutaneous MRI-guided laser ablation. All tumors (diameter range 1.5-3.8 cm, mean 2.7 cm) were biopsy-proven RCCs. By using a 0.23 T open MRI system and general anesthesia in patients, one to four (mean 2.6) laser fibers were placed and the tumors were ablated under near real-time MRI control by observing the signal void caused by the temperature change in the heated tissue. The treatment was considered successful if the tumor showed no contrast enhancement at follow-up imaging. Results: All except one tumor were successfully ablated in one session. The first patient treated showed enhancing residual tumor in post-procedural MRI; she has thus far declined retreatment. One complication, a myocardial infarction, occurred; all other patients tolerated the procedure well. No local recurrence was discovered during the follow-up (range 12-30 months, mean 20 months). Conclusion: In this small group of patients with relatively short follow-up period, MRI-guided percutaneous laser ablation proved to be a promising treatment option for small RCCs

  2. 3D X-ray imaging methods in support catheter ablations of cardiac arrhythmias.

    Stárek, Zdeněk; Lehar, František; Jež, Jiří; Wolf, Jiří; Novák, Miroslav

    2014-10-01

    Cardiac arrhythmias are a very frequent illness. Pharmacotherapy is not very effective in persistent arrhythmias and brings along a number of risks. Catheter ablation has became an effective and curative treatment method over the past 20 years. To support complex arrhythmia ablations, the 3D X-ray cardiac cavities imaging is used, most frequently the 3D reconstruction of CT images. The 3D cardiac rotational angiography (3DRA) represents a modern method enabling to create CT like 3D images on a standard X-ray machine equipped with special software. Its advantage lies in the possibility to obtain images during the procedure, decreased radiation dose and reduction of amount of the contrast agent. The left atrium model is the one most frequently used for complex atrial arrhythmia ablations, particularly for atrial fibrillation. CT data allow for creation and segmentation of 3D models of all cardiac cavities. Recently, a research has been made proving the use of 3DRA to create 3D models of other cardiac (right ventricle, left ventricle, aorta) and non-cardiac structures (oesophagus). They can be used during catheter ablation of complex arrhythmias to improve orientation during the construction of 3D electroanatomic maps, directly fused with 3D electroanatomic systems and/or fused with fluoroscopy. An intensive development in the 3D model creation and use has taken place over the past years and they became routinely used during catheter ablations of arrhythmias, mainly atrial fibrillation ablation procedures. Further development may be anticipated in the future in both the creation and use of these models.

  3. Typical flutter ablation as an adjunct to catheter ablation of atrial fibrillation

    Dipen Shah

    2008-12-01

    Full Text Available Typical atrial flutter and atrial fibrillation are frequently observed to coexist(1 .  In the current context of interventional electrophysiology, curative or at least definitive ablation is available for both arrhythmias. Despite their coexistence, it is not clear whether typical flutter ablation is necessary in all patients undergoing catheter ablation of atrial fibrillation. The following review explores the pathophysiology of both arrhythmias, their interrelationships and the available data pertaining to this theme.

  4. Use of a circular mapping and ablation catheter for ablation of atypical right ventricular outflow tract arrhythmia.

    Katritsis, Demosthenes G; Giazitzoglou, Eleftherios; Paxinos, George

    2010-02-01

    A new technique for ablation of persistent ectopic activity with atypical electrocardiographic characteristics at the vicinity of the right ventricular outflow tract is described. A new circular mapping and ablation catheter initially designed for pulmonary vein ablation was used. Abolition of ectopic activity was achieved with minimal fluoroscopy and ablation times.

  5. Laser ablation - inductively coupled plasma mass spectrometry (LA-ICP-MS): Novel applications for coal research

    Booth, C.A.; Spears, D.A.

    1999-07-01

    Laser Ablation - Inductively Coupled Plasma - Mass Spectrometry (LA-ICP-MS) has enormous potential in coal research. Element concentrations are determined with limits of detection currently in the parts per billion range, whilst spatial resolution as low as 10 microns can be achieved using the CETAC Technologies LSX-100 laser ablation system. Calibration of the LA-ICP-MS systems is notoriously difficult but in this paper the authors review two different techniques used in Sheffield, which allow trace element concentrations of whole coals (bituminous) and minerals and macerals within the coal to be determined. The first technique involves calibrating the system with PF grade coal samples in order that trace element concentrations can directly be determined after ablation of a solid coal or pressed coal sample. Using this technique, potentially hazardous trace elements such as As, Cd, Pb and Hg can be detected and measured even in the low parts per billion concentration (mg/Kg) range. The second application utilizes the spatial resolution of the laser to measure element concentrations in individual coal components. In this paper the results from ablating pyrite framboids in polished sections of the coal are discussed. Elemental information is obtained throughout the ablation procedure and this is then calibrated against the Fe content in order to establish the concentration of an element per 1% pyritic iron.

  6. Tracking Perfluorocarbon Nanoemulsion Delivery by 19F MRI for Precise High Intensity Focused Ultrasound Tumor Ablation

    Shin, Soo Hyun; Park, Eun-Joo; Min, Changki; Choi, Sun Il; Jeon, Soyeon; Kim, Yun-Hee; Kim, Daehong

    2017-01-01

    Perfluorocarbon nanoemulsions (PFCNEs) have recently been undergoing rigorous study to investigate their ability to improve the therapeutic efficacy of tumor ablation by high intensity focused ultrasound (HIFU). For precise control of PFCNE delivery and thermal ablation, their accumulation and distribution in a tumor should be quantitatively analyzed. Here, we used fluorine-19 (19F) magnetic resonance imaging (MRI) to quantitatively track PFCNE accumulation in a tumor, and analyzed how intra-tumoral PFCNE quantities affect the therapeutic efficacy of HIFU treatment. Ablation outcomes were assessed by intra-voxel incoherent motion analysis and bioluminescent imaging up to 14 days after the procedure. Assessment of PFCNE delivery and treatment outcomes showed that 2-3 mg/mL of PFCNE in a tumor produces the largest ablation volume under the same HIFU insonation conditions. Histology showed varying degrees of necrosis depending on the amount of PFCNE delivered. 19F MRI promises to be a valuable platform for precisely guiding PFCNE-enhanced HIFU ablation of tumors. PMID:28255351

  7. Catheter ablation and surgical tneatment of atrial fibrillation with valvular heart disease%外科射频消融术与经导管消融术治疗瓣膜病性房颤的疗效对比

    卢春山; 柳景华; 马长生; 孟旭; 罗毅; 刘旭; 董建增; 刘兴鹏

    2008-01-01

    Objective Catheter ablation of atrial fibrillation(AF) has became another nonpharmacologic therapeutic option for valvular heart divine with AF. The modified Cox maze procedure was the traditional treatment of AF during cardiac surgery. The purpose of this study wss to compare the clinical outcomes of the two approaches in patients with rheumatic valvular heart disease and AF. Methods From January 2004 to March 2006, patients with valvular heart disease with AF were inchuded. Catheter ablation(group 2) versus surgical treatment( group 1) for rheumatic heart disease with AF. Results Group 1 and 2 did not differ in terms of baseline characteristics. The perioperative mortality rate was not significantly different between the two groups. The maintenances of sinus rhythm were 90%, 82% respectively for group 2 in paroxysmal AF with LAd <50 mm, and case history < 1 year. The overall cumulative rate of sinus rhythm were75% in group 1 [(14±10) months] and 64% in group 2 [follow-up time, (14±10) months] , statistically significant. Conchusion The nsdiofrenquency (RF) ablation procedure during surgical treatment for valve heart disease with atrial fibrillation is a single, effective therapeutic option, allowing recovery of the sinus rhythm in the great majority of patients with atrial. fibrillation. While cstheter ablation is also a safe and effective means of curing atrial fibllation in paroxysmal AF with LAd <50 mm (<1 year).%目的 比较心内直视下射频迷宫术与介入导管消融术治疗合并心脏瓣膜病的心房颤动临床结果.方法 2004年1月到2006年3月因心脏瓣膜病合并心房颤动行瓣膜置换时加射频迷宫术60例,其中男34例,女26例;平均(57±11)岁.瓣膜置换术后在三维电解剖标测系统(CABTO)指导下进行经皮经导管环肺静脉消融治疗66例,其中男40例,女26例;平均(55±10)岁.结果 导管消融组随访(14±10)个月,窦性心律维持率64%.外科射频迷宫组随访(13±9)

  8. Cryoballoon or Radiofrequency Ablation for Paroxysmal Atrial Fibrillation.

    Chun, KR; Bestehorn, K; Pocock, SJ; FIRE AND ICE Investigators; , COLLABORATORS; Kuck, KH; Metzner, A; Ouyang, F; Chun, J; Fürnkranz, A; Elvan, A.; Arentz, T.; Kühne, M.; Sticherling, C; Gellér, L

    2016-01-01

    BACKGROUND: Current guidelines recommend pulmonary-vein isolation by means of catheter ablation as treatment for drug-refractory paroxysmal atrial fibrillation. Radiofrequency ablation is the most common method, and cryoballoon ablation is the second most frequently used technology. METHODS: We conducted a multicenter, randomized trial to determine whether cryoballoon ablation was noninferior to radiofrequency ablation in symptomatic patients with drug-refractory paroxysmal atrial fibrillatio...

  9. Angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors in the liver: A feasibility study

    Park, Sung Il; Shin, Min Woo; Shin, Won Seon [Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); and others

    2016-09-15

    To evaluate the feasibility of angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular liver tumors abutting abdominal wall, in order to traverse normal liver parenchyma, and thereby, obtain favorable configuration of ablation margin. In this study, we retrospectively analyzed 15 small superficial subcapsular liver tumors abutting abdominal wall in 15 patients, treated with radiofrequency ablation from March 2013 to June 2015 using a cool-tip electrode manually modified to create 25–35° angle at the junction between exposed and insulated segments. The tumors were hepatocellular carcinoma (n = 13) and metastases (n = 2: cholangiocellular carcinoma and rectosigmoid cancer), with maximum diameter of 10–26 mm (mean, 15.68 ± 5.29 mm). Under ultrasonographic guidance, the electrode tip was advanced to the depth of the tumors' epicenter about 1 cm from the margin. The tip was re-directed to penetrate the tumor for radiofrequency ablation. Minimal ablation margin was measured at immediate post-treatment CT. Radiological images and medical records were evaluated for success rate, length of minimal ablation margin and complications. Technical success rate of obtaining complete necrosis of the tumors was 100%, with no procedure-related complication. Minimal ablation margin ranged from 3–12 mm (mean, 7.07 ± 2.23 mm). CT/MRI follow-up at 21–1022 days (mean, 519.47 ± 304.51 days) revealed no local recurrence, but distant recurrence in 9 patients. Using an angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors abutting abdominal wall may be a feasible technique for obtaining adequate ablation margin and lower complication rate.

  10. Endoscopic ablation of Barrett's esophagus using the second generation argon plasma coagulation: a prospective randomized controlled trail

    Li Zhang; Lei Dong; Jia Liu; Xiaolan Lu; Jun Zhang

    2009-01-01

    Objective:To investigate the efficacy and safety of the second generation argon plasma coagulation(VIO APC) in the ablation of Barrett's Esophagus. Methods:A total of 35 patients with uncomplicated Barrett's esophagus entered into a prospective, randomized, unblinded study comparing the treatment VIO APC combined with a proton pump inhibiter with a proton pump inhibiter administered alone. VIO APC was performed at a power setting of 40W, and argon gas flow at 1.5-2.0 L/min, and "forced" mode. Ablative treatment was repeated until either no Barrett's epithelium remained or a maximum of 5 treatment sessions occurred. Results:In the ablation group, macroscopic complete ablation was achieved in 14 of 18 patients, and complete ablation confirmed by histology in 12 of 18 patients (P<0.01). Buried glands were observed in 2 patients who had achieved macroscopic ablation. The Barrett's mucosa averaged a reduction of 65%(range 50-75%) in the remaining 4 patients. In the control group, only 2 patients had partial regression, median 30%(range 20-40%).In the ablation group, post-treatment 4 patients had transient retrosternal pain, and 3 patients had mild epigastric discomfort. One patient had a small hemorrhage during the procedure, which ceased after norepinephrine and thrombosin were administered through the endoscope biopsy channel. No adverse events were observed in the control group. During 11.8(4-15) months follow-up, patients who had achieved the complete ablation have no evidence of relapse of Barrett's esophagus. Conclusion:VIO APC with a relatively low power setting can effectively ablate the Barrett's mucosa. No severe adverse events were observed. Long-term follow-up is needed to assess cancer prevention and the durability of the neo-squamous epithelium.

  11. Angled Cool-Tip Electrode for Radiofrequency Ablation of Small Superficial Subcapsular Tumors in the Liver: A Feasibility Study

    Park, Sung Il [Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul 03722 (Korea, Republic of); Kim, Il Jung [Department of Radiology, Bucheon St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Bucheon 14647 (Korea, Republic of); Lee, Shin Jae [Department of Radiology, CHA Bundang Medical Center, CHA University, Seongnam 13496 (Korea, Republic of); Shin, Min Woo; Shin, Won Sun; Chung, Yong Eun; Kim, Gyoung Min; Kim, Man Deuk; Won, Jong Yun; Lee, Do Yun [Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul 03722 (Korea, Republic of); Choi, Jin Sub [Department of Surgery, Severance Hospital, Yonsei University College of Medicine, Seoul 03722 (Korea, Republic of); Han, Kwang-Hyub [Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul 03722 (Korea, Republic of)

    2016-11-01

    To evaluate the feasibility of angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular liver tumors abutting abdominal wall, in order to traverse normal liver parenchyma, and thereby, obtain favorable configuration of ablation margin. In this study, we retrospectively analyzed 15 small superficial subcapsular liver tumors abutting abdominal wall in 15 patients, treated with radiofrequency ablation from March 2013 to June 2015 using a cool-tip electrode manually modified to create 25–35° angle at the junction between exposed and insulated segments. The tumors were hepatocellular carcinoma (n = 13) and metastases (n = 2: cholangiocellular carcinoma and rectosigmoid cancer), with maximum diameter of 10–26 mm (mean, 15.68 ± 5.29 mm). Under ultrasonographic guidance, the electrode tip was advanced to the depth of the tumors' epicenter about 1 cm from the margin. The tip was re-directed to penetrate the tumor for radiofrequency ablation. Minimal ablation margin was measured at immediate post-treatment CT. Radiological images and medical records were evaluated for success rate, length of minimal ablation margin and complications. Technical success rate of obtaining complete necrosis of the tumors was 100%, with no procedure-related complication. Minimal ablation margin ranged from 3–12 mm (mean, 7.07 ± 2.23 mm). CT/MRI follow-up at 21–1022 days (mean, 519.47 ± 304.51 days) revealed no local recurrence, but distant recurrence in 9 patients. Using an angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors abutting abdominal wall may be a feasible technique for obtaining adequate ablation margin and lower complication rate.

  12. Thermal ablation of liver metastases. Current status and perspectives; Thermische Ablation von Lebermetastasen. Aktueller Stand und Perspektiven

    Vogl, T.; Mack, M.; Straub, R.; Zangos, S.; Woitaschek, D.; Eichler, K.; Engelmann, K. [Inst. fuer Diagnostische und Interventionelle Radiologie, Univ. Frankfurt (Germany)

    2001-01-01

    Purpose. To present thermal ablation of liver metastases via laser induced thermotherapy. Material and methods. Different technical procedures of thermal ablation and online monitoring are used, as there are the MR-guided laser induced thermotherapy (LITT) and the radiofrequency ablation thermotherapy (RF). Results. In a prospective non randomized study 606 patients with liver metastases were treated via MR-guided laserinduced thermotherapy. Inclusion criteria were the exclusion of extrahepatic tumor spread and a number of metastases lower than 5 and a size lower than 50 mm in diameter. The local tumor control rate in the 3 month and 6 month control study was 98,3%, the complication rate 3,5% (clinically relevant: 1,2%). The mean survival rate was 40,9 months for all patients with liver metastases without statistically relevant differences for various primaries, like colorectal carcinoma, breast cancer and various other tumors. Results for radiofrequency are so far limited with incidence of a higher local tumor recurrence rate versus LITT. Conclusion. MR-guided LITT results in a high local tumor control rate with improved survival. (orig.) [German] Zielsetzung. Vorstellung der thermischen Ablation von Lebermetastasen mittels laserinduzierter Thermotherapie (LITT). Material und Methodik. Verschiedene technische Verfahren der Ablation sowie 'Online-monitoring-Verfahren' werden vorgestellt. Derzeit gaengige Verfahren der Thermoablation stellen die MR-gesteuerte laserinduzierte Thermotherapie (LITT) sowie die Radiofrequenzablation (RF) dar. Ergebnisse. Im Rahmen einer prospektiven, nichtrandomisierten Studie wurden bislang 606 Patienten mit Lebermetastasen unterschiedlicher Primaertumoren mittels LITT perkutan therapiert. Die erzielte lokale Tumorkontrolle in der 3- bzw. 6-Monatskontrolle betrug dabei 98,3%, die Rate klinisch nicht relevanter Komplikationen 3,5%, die Rate klinisch relevanter Komplikationen 1,2%. Die mittlere Ueberlebensrate fuer das

  13. Egocentric spatial orientation in a water maze by rats subjected to transection of the fimbria-fornix and/or ablation of the prefrontal cortex

    Mogensen, Jesper; Moustgaard, Anette; Khan, Usman;

    2005-01-01

    prefrontal cortex, hippocampus, fimbria-fornix, egocentrisk spatial orientering, vandlabyrint, adfærdsstrategier, kognitive strategier, funktionel genopretning, rehabilitering, problemløsning, rotter......prefrontal cortex, hippocampus, fimbria-fornix, egocentrisk spatial orientering, vandlabyrint, adfærdsstrategier, kognitive strategier, funktionel genopretning, rehabilitering, problemløsning, rotter...

  14. Ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation

    王建安; 孙勇; 何红

    2003-01-01

    Objective: to evaluate the efficacy and safety of ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation. Methods: The study population consisted of 9 patients with 5 males and 4 females enrolled consecutively who had idiopathic paroxysmal atrial fibrillation(AF). The ultrasound balloon was positioned through a special sheath to the orifice of the target vein by a transseptal procedure. The balloon was inflated with contrast-mixed saline (contrast: saline = 1:4) whose volume was decided by the diameter of the target pulmonary vein. The ablation energy was usually set up at 35 to 40 watts with temperature controlled at 60℃. The duration of each ablation was about 120 seconds which was repeated not over 10 times. Results: The average duration of the total procedure was 132±68 min for our patients. The average fluoroscopy time was 33±17 min. With a mean follow-up of 16±8 months after the procedure, AF was completely eliminated in 4 patients without antiarrhythmic drugs. The episodes of atrial fibrillation were eliminated in 2 patients with low dosage of oral amiodarone (0.1, once daily) which was ineffective before the procedure. The frequency of episodes was similar to that before the procedure in 3 patients. There were no complications such as hemopericardium, air embolism and stenosis of the pulmonary veins by angiography, related to the procedure. Conclusion: Ultrasound ablation of the pulmonary veins is a new approach to treat paroxysmal atrial fibrillation. Before we determined its value, we need to do more researches with bigger sample, randomization and comparison design.

  15. Ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation

    王建安; 孙勇; 何红

    2003-01-01

    Objective : to evaluate the efficacy and safety of ultrasound ablation of pulmonary veins for treatment of paroxysmal atrial fibrillation. Methods : The study population consisted of 9 patients with 5 males and 4 females enrolled consecutively who had idiopathic paroxysmal atrial fibrillation(AF) . The ultrasound balloon was positioned through a special sheath to the orifice of the target vein by a transseptal procedure. The balloon was inflated with contrast-mixed saline (contrast: saline = 1:4) whose volume was decided by the diameter of the target pulmonary vein. The ablation energy was usually set up at 35 to 40 watts with temperature controlled at 60℃ . The duration of each ablation was about 120 seconds which was repeated not over 10 times. Results: The average duration of the total procedure was 132± 68 min for our patients. The average fluoroscopy time was 33 ±17 min. With a mean follow-up of 16 ±8 months after the procedure, AF was completely eliminated in 4 patients without antiarrhythmic drugs. The episodes of atrial fibrillation were eliminated in 2 patients with low dosage of oral amiodarone (0.1, once daily) which was ineffective before the procedure. The frequency of episodes was similar to that before the procedure in 3 patients. There were no complications such as hemopericardium, air embolism and stenosis of the pulmonary veins by angiography, related to the procedure. Conclusion : Ultrasound ablation of the pulmonary veins is a new approach to treat paroxysmal atrial fibrillation. Before we determined its value, we need to do more researches with bigger sample, randomization and comparison design.

  16. Possible anxiolytic effects of taurine in the mouse elevated plus-maze.

    Chen, Si Wei; Kong, Wei Xi; Zhang, Yi Jing; Li, Yu Lei; Mi, Xiao Juan; Mu, Xiao Shuo

    2004-08-01

    The effects of taurine, an inhibitory amino acid, on the behavior of male mice were examined in the elevated plus-maze test of anxiety. Acute taurine treatment (60 mg/kg, PO) significantly increased the percentage of time spent in the open arms. Moreover, when taurine was administered daily for seven days and the plus-maze test was conducted 40 minutes after the last administration, a significant increase of the percentage of time in the open arms was observed even at dose of 2.5 mg/kg, however the open arm entries and the total entries were unaffected at any dose tested. In order to get a comprehensive profile of drug action, detailed behavioral analyses were further exerted. Single administration of 60 mg/kg taurine can significantly reduce the total rears. The results suggest that taurine have some anxiolytic-like properties, although its effects seem more limited and are not consistent with those presented by classic anxiolytics, such as diazepam.

  17. Heading which way? Y-maze chemical assays: not all crustaceans are alike

    Kenning, Matthes; Lehmann, Philipp; Lindström, Magnus; Harzsch, Steffen

    2015-09-01

    In a world full of chemicals, many crustaceans rely on elaborate olfactory systems to guide behaviors related to finding food or to assess the presence of conspecifics and predators. We analyzed the responses of the isopod Saduria entomon to a range of stimuli by which the animal is likely to encounter in its natural habitat using a Y-maze bioassay. In order to document the efficiency of the experimental design, the same bioassay was used to test the behavior of the crayfish Procambarus fallax whose ability to track odors is well documented. The crayfish performed well in the Y-maze and were able to locate the source of a food-related odor with high fidelity. The isopod S. entomon reacted indifferently or with aversion to most of the stimuli applied. In 1800 trials, only four out of 15 different stimuli yielded statistically significant results, and only one odorant was found to be significantly attractive. The findings raise several questions whether the stimuli presented and/or the experimental setup used represents an ecologically relevant situation for S. entomon. In each instance, our experiments illustrate that established methods cannot be readily transferred from one species to another.

  18. Water Associated Zero Maze: A novel rat test for long term traumatic re-experiencing

    Gilad eRitov

    2014-01-01

    Full Text Available Often, freezing and startle behaviors in the context of a previously experienced stress are taken as an indication of posttraumatic stress disorder (PTSD-like symptoms in rats. However, PTSD is characterized by large individual variations of symptoms. In order to take into consideration the complex and long term distinctive variations in effects of trauma exposure additional behavioral measures are required.The current study used a novel behavioral test, the Water Associated Zero Maze (WAZM. This test was planned to enable a formation of an association between the context of the maze and an underwater trauma or swim stress in order to examine the impact of exposure to the context which immediately precedes a stressful or a traumatic experience on rat's complex behavior. Rats were exposed to the WAZM and immediately after to an underwater trauma or short swim. One month later rats were re-exposed to the context of the WAZM while their behavior was video recorded. Furthermore, c-Fos expression in the amygdala was measured 90 min after this exposure.The results of the current study indicate that the WAZM can be used to discern behavioral changes measured a long time after the actual traumatic or stressful events. Furthermore, the behavioral changes detected were accompanied by changes of c-Fos expression in the amygdala of exposed rats. We suggest that the WAZM can be used to model traumatic memories re-experiencing in rodent models of human stress-related pathologies such as PTSD.

  19. Modafinil and memory: effects of modafinil on Morris water maze learning and Pavlovian fear conditioning.

    Shuman, Tristan; Wood, Suzanne C; Anagnostaras, Stephan G

    2009-04-01

    Modafinil has been shown to promote wakefulness and some studies suggest the drug can improve cognitive function. Because of many similarities, the mechanism of action may be comparable to classical psychostimulants, although the exact mechanisms of modafinil's actions in wakefulness and cognitive enhancement are unknown. The current study aims to further examine the effects of modafinil as a cognitive enhancer on hippocampus-dependent memory in mice. A high dose of modafinil (75 mg/kg ip) given before training improved acquisition on a Morris water maze. When given only before testing, modafinil did not affect water maze performance. We also examined modafinil (0.075 to 75 mg/kg) on Pavlovian fear conditioning. A low dose of pretraining modafinil (0.75 mg/kg) enhanced memory of contextual fear conditioning (tested off-drug 1 week later) whereas a high dose (75 mg/kg) disrupted memory. Pretraining modafinil did not affect cued conditioning at any dose tested, and immediate posttraining modafinil had no effect on either cued or contextual fear. These results suggest that modafinil's effects of memory are more selective than amphetamine or cocaine and specific to hippocampus-dependent memory.

  20. Erythropoietin Improves Place Learning in an 8-Arm Radial Maze in Fimbria-Fornix Transected Rats

    Hana Malá

    2005-01-01

    Full Text Available Systemically administered human recombinant erythropoietin (EPO may have the potential to reduce the cognitive and behavioral symptoms of mechanical brain injury. In a series of studies, we address this possibility. We previously found that EPO given to fimbriafornix transected rats at the moment of injury could substantially improve the posttraumatic acquisition of an allocentric place learning task when such a task is administered in a water maze. Due to the clinical importance of such results, it is important to scrutinize whether the therapeutic effect of EPO is specific to the experimental setup of our original experiments or generalizes across test situations. Consequently, here we studied the effects of similarly administered EPO in fimbria-fornix transected and control operated rats, respectively, evaluating the posttraumatic behavioral/cognitive abilities in an allocentric place learning task administered in an 8-arm radial maze. The administration of EPO to the hippocampally injured rats was associated with a virtually complete elimination of the otherwise severe behavioral impairment caused by fimbria-fornix transection. In contrast, EPO had no detectable effect on the task acquisition of non-lesioned animals. The results of the present study confirm our previous demonstration of EPO's ability to reduce or eliminate the behavioral/cognitive consequences of mechanical injury to the hippocampus, while adding the important observation that such a therapeutic effect is not restricted to the specific experimental setup previously studied.

  1. The effects of abused inhalants on mouse behavior in an elevated plus-maze.

    Bowen, S E; Wiley, J L; Balster, R L

    1996-09-26

    Previous research has shown that abused inhalants (i.e., the volatile solvents) share some of the pharmacological properties of drugs used in the treatment of anxiety. In an attempt to further examine commonalities in the effects of inhalants and central nervous system depressant drugs, the behavioral effects of inhaled 1,1,1-trichloroethane, toluene, methoxyflurane and the convulsant vapor flurothyl were examined and compared to those of diazepam in the elevated plus-maze, a test used to predict antianxiety effects. After inhalant exposure or diazepam injection, mice were placed in the center of an elevated plus-maze and the number of entries and time spent in each type of arm (open versus closed) were measured during 5-min tests. Exposure to increasing concentrations of toluene produced concentration-related increases in the total number of open arm entries and the total time spent on the open arms, a pattern of behavioral effects similar to that produced by diazepam. A similar pattern was observed for increasing concentrations of 1,1,1-trichloroethane and methoxyflurane but changes in open arm activity were only observed at concentrations that increased locomotor activity. Conversely, only decreases in open arm time and number of entries were observed for flurothyl. The increasing evidence for commonalities in the behavioral effects of volatile solvents and depressant drugs may provide a foundation for understanding the neurobehavioral basis of inhalant abuse.

  2. Coriandrum sativum: evaluation of its anxiolytic effect in the elevated plus-maze.

    Emamghoreishi, Masoumeh; Khasaki, Mohammad; Aazam, Maryam Fath

    2005-01-15

    The clinical applications of benzodiazepines as anxiolytics are limited by their unwanted side effects. Therefore, the development of new pharmacological agents is well justified. Among medicinal plants, Coriandrum sativum L. has been recommended for relief of anxiety and insomnia in Iranian folk medicine. Nevertheless, no pharmacological studies have thus far evaluated its effects on central nervous system. Therefore, the aim of this study was to examine if the aqueous extract of Coriandrum sativum seed has anxiolytic effect in mice. Additionally, its effect on spontaneous activity and neuromuscular coordination were evaluated. The anxiolytic effect of aqueous extract (10, 25, 50, 100 mg/kg, i.p.) was examined in male albino mice using elevated plus-maze as an animal model of anxiety. The effects of the extract on spontaneous activity and neuromuscular coordination were assessed using Animex Activity Meter and rotarod, respectively. In the elevated plus-maze, aqueous extract at 100 mg/kg showed an anxiolytic effect by increasing the time spent on open arms and the percentage of open arm entries, compared to control group. Aqueous extract at 50, 100 and 500 mg/kg significantly reduced spontaneous activity and neuromuscular coordination, compared to control group. These results suggest that the aqueous extract of Coriandrum sativum seed has anxiolytic effect and may have potential sedative and muscle relaxant effects.

  3. A computational model for exploratory activity of rats with different anxiety levels in elevated plus-maze.

    Costa, Ariadne A; Morato, Silvio; Roque, Antonio C; Tinós, Renato

    2014-10-30

    The elevated plus-maze is an apparatus widely used to study the level of anxiety in rodents. The maze is plus-shaped, with two enclosed arms and two open arms, and elevated 50cm from the floor. During a test, which usually lasts for 5min, the animal is initially put at the center and is free to move and explore the entire maze. The level of anxiety is measured by variables such as the percentage of time spent and the number of entries in the enclosed arms. High percentage of time spent at and number of entries in the enclosed arms indicate anxiety. Here we propose a computational model of rat behavior in the elevated plus-maze based on an artificial neural network trained by a genetic algorithm. The fitness function of the genetic algorithm is composed of reward (positive) and punishment (negative) terms, which are incremented as the computational agent (virtual rat) moves in the maze. The punishment term is modulated by a parameter that simulates the effects of different drugs. Unlike other computational models, the virtual rat is built independently of prior known experimental data. The exploratory behaviors generated by the model for different simulated pharmacological conditions are in good agreement with data from real rats.

  4. Orientation of lizards in a Morris water-maze: roles of the sun compass and the parietal eye.

    Foà, Augusto; Basaglia, Francesca; Beltrami, Giulia; Carnacina, Margherita; Moretto, Elisa; Bertolucci, Cristiano

    2009-09-15

    The present study examined for the first time whether a Morris water-maze can be used to explore compass and other orientation mechanisms in the ruin lizard Podarcis sicula. In the open field, during sunny days, lizards were individually trained to swim from the center of the water maze onto a hidden platform (the goal), positioned at the periphery of the maze in a single compass direction. The goal was invisible because it was placed just beneath the water surface and the water was rendered opaque. The results showed that lizards learn to swim directly towards the hidden goal under the sun in the absence of visual feature cues. We further examined whether the observed orientation response would be due to lizards learning the spatial position of the goal relative to the sun's azimuth, i.e. to the use of a time-compensated sun compass. Lizards reaching learning criteria were subjected to 6 h clock-shift (fast or slow), and tested for goal orientation in the Morris water-maze. Results demonstrated that the learned orientation response is mediated by a time-compensated sun compass. Further investigations provided direct evidence that in ruin lizards an intact parietal eye is required to perform goal orientation under the sun inside a Morris water-maze, and that other brain photoreceptors, like the pineal or deep brain photoreceptors, are not involved in orientation.

  5. Physical processes of laser tissue ablation

    Furzikov, Nickolay P.

    1991-05-01

    The revised ablation model applicable to homogeneous tissues is presented. It is based on the thermal mechanism and involves the instability of the laserinduced evaporation (thermodestruction) front the growth of the surface ripple structure the interference of the laser wave and of the surface wave arising by diffraction on the ripples Beer''s law violation the pulsed thermodestruction of the organic structural component the tissue water boiling and gas dynamic expansion of the resulting products into the surrounding medium which is followed by the shock wave formation. The UV and IR ablation schemes were implemented and compared to the corneal ablation experiments. The initial ablation pressure and temperature are given restored from the timeofflight measurements of the supersonic expansion of the product. 1.

  6. Nanosecond laser ablation of silver nanoparticle film

    Chung, Jaewon; Han, Sewoon; Lee, Daeho; Ahn, Sanghoon; Grigoropoulos, Costas P.; Moon, Jooho; Ko, Seung H.

    2013-02-01

    Nanosecond laser ablation of polyvinylpyrrolidone (PVP) protected silver nanoparticle (20 nm diameter) film is studied using a frequency doubled Nd:YAG nanosecond laser (532 nm wavelength, 6 ns full width half maximum pulse width). In the sintered silver nanoparticle film, absorbed light energy conducts well through the sintered porous structure, resulting in ablation craters of a porous dome shape or crown shape depending on the irradiation fluence due to the sudden vaporization of the PVP. In the unsintered silver nanoparticle film, the ablation crater with a clean edge profile is formed and many coalesced nanoparticles of 50 to 100 nm in size are observed inside the ablation crater. These results and an order of magnitude analysis indicate that the absorbed thermal energy is confined within the nanoparticles, causing melting of nanoparticles and their coalescence to larger agglomerates, which are removed following melting and subsequent partial vaporization.

  7. Ablative Ceramic Foam Based TPS Project

    National Aeronautics and Space Administration — A novel composite material ablative TPS for planetary vehicles that can survive a dual heating exposure is proposed. NextGen's TPS concept is a bi-layer functional...

  8. Nanoscale ablation through optically trapped microspheres

    Fardel, Romain; McLeod, Euan; Tsai, Yu-Cheng; Arnold, Craig B.

    2010-10-01

    The ability to directly create patterns with size scales below 100 nm is important for many applications where the production or repair of high resolution and density features is needed. Laser-based direct-write methods have the benefit of being able to quickly and easily modify and create structures on existing devices, but ablation can negatively impact the overall technique. In this paper we show that self-positioning of near-field objectives through the optical trap assisted nanopatterning (OTAN) method allows for ablation without harming the objective elements. Small microbeads are positioned in close proximity to a substrate where ablation is initiated. Upon ablation, these beads are temporarily displaced from the trap but rapidly return to the initial position. We analyze the range of fluence values for which this process occurs and find that there exists a critical threshold beyond which the beads are permanently ejected.

  9. Support for High Power Laser Ablation 2010

    2010-04-16

    Femtosecond Pulsed laser Ablation and Deposition Marta Castillejo Instituto de Quimica Fisica Rocasolano, CSIC, Serrano 119, 28006 Madrid, Spain Tel:+34...system to transition the laser cavity’s low pressure to the ambient pressure outside the device. Diffusers use a series of shocks in a duct to...especially the incident laser fluence and ambient pressure. New results highlight the influence of the ambient pressure on ablation physics from the

  10. Principles of the radiative ablation modeling

    Saillard, Yves; Arnault, Philippe; Silvert, Virginie

    2010-12-01

    Indirectly driven inertial confinement fusion (ICF) rests on the setting up of a radiation temperature within a laser cavity and on the optimization of the capsule implosion ablated by this radiation. In both circumstances, the ablation of an optically thick medium is at work. The nonlinear radiation conduction equations that describe this phenomenon admit different kinds of solutions called generically Marshak waves. In this paper, a completely analytic model is proposed to describe the ablation in the subsonic regime relevant to ICF experiments. This model approximates the flow by a deflagrationlike structure where Hugoniot relations are used in the stationary part from the ablation front up to the isothermal sonic Chapman-Jouguet point and where the unstationary expansion from the sonic point up to the external boundary is assumed quasi-isothermal. It uses power law matter properties. It can also accommodate arbitrary boundary conditions provided the ablation wave stays very subsonic and the surface temperature does not vary too quickly. These requirements are often met in realistic situations. Interestingly, the ablated mass rate, the ablation pressure, and the absorbed radiative energy depend on the time history of the surface temperature, not only on the instantaneous temperature values. The results compare very well with self-similar solutions and with numerical simulations obtained by hydrodynamic code. This analytic model gives insight into the physical processes involved in the ablation and is helpful for optimization and sensitivity studies in many situations of interest: radiation temperature within a laser cavity, acceleration of finite size medium, and ICF capsule implosion, for instance.

  11. Differential induction of c-Jun and Fos-like proteins in rat hippocampus and dorsal striatum after training in two water maze tasks.

    Teather, Lisa A; Packard, Mark G; Smith, Diane E; Ellis-Behnke, Rutledge G; Bazan, Nicolas G

    2005-09-01

    Research examining the neuroanatomical bases of memory in mammals suggests that the hippocampus and dorsal striatum are parts of independent memory systems that mediate "cognitive" and stimulus-response "habit" memory, respectively. At the molecular level, increasing evidence indicates a role for immediate early gene (IEG) expression in memory formation. The present experiment examined whether acquisition of cognitive and habit memory result in differential patterns of IEG protein product expression in these two brain structures. Adult male Long-Evans rats were trained in either a hippocampal-dependent spatial water maze task, or a dorsal striatal-dependent cued water maze task. Ninety minutes after task acquisition, brains were removed and processed for immunocytochemical procedures, and the number of cells expressing Fos-like immunoreactivity (Fos-like-IR) and c-Jun-IR in sections from the dorsal hippocampus and the dorsal striatum were counted. In the dorsal hippocampus of rats trained in the spatial task, there were significantly more c-Jun-IR pyramidal cells in the CA1 and CA3 regions, relative to rats that had acquired the cued task, yoked controls (free-swim), or naïve (home cage) rats. Relative to rats receiving cued task training and control conditions, increases in Fos-like IR were also observed in the CA1 region of rats trained in the spatial task. In rats that had acquired the cued task, patches of c-Jun-IR were observed in the posteroventral striatum; no such patches were evident in rats trained in the spatial task, yoked-control rats, or naïve rats. The results demonstrate that IEG protein product expression is up-regulated in a task-dependent and brain structure-specific manner shortly after acquisition of cognitive and habit memory tasks.

  12. Interest of Electrostimulation of Peripheral Motor Nerves during Percutaneous Thermal Ablation

    Tsoumakidou, Georgia, E-mail: gtsoumakidou@yahoo.com; Garnon, Julien, E-mail: juliengarnon@gmail.com; Ramamurthy, Nitin, E-mail: nitin_ramamurthy@hotmail.com; Buy, Xavier, E-mail: xbuy@ymail.com; Gangi, Afshin, E-mail: gangi@unistra.fr [University Hospital of Strasbourg (France)

    2013-12-15

    Purpose: We present our experience of utilizing peripheral nerve electrostimulation as a complementary monitoring technique during percutaneous thermal ablation procedures; and we highlight its utility and feasibility in the prevention of iatrogenic neurologic thermal injury. Methods: Peripheral motor nerve electrostimulation was performed in 12 patients undergoing percutaneous image-guided thermal ablations of spinal/pelvic lesions in close proximity to the spinal cord and nerve roots. Electrostimulation was used in addition to existing insulation (active warming/cooling with hydrodissection, passive insulation with CO{sub 2} insufflation) and temperature monitoring (thermocouples) techniques. Impending neurologic deficit was defined as a visual reduction of muscle response or need for a stronger electric current to evoke muscle contraction, compared with baseline. Results: Significant reduction of the muscle response to electrostimulation was observed in three patients during the ablation, necessitating temporary interruption, followed by injection of warm/cool saline. This resulted in complete recovery of the muscle response in two cases, while for the third patient the response did not improve and the procedure was terminated. No patient experienced postoperative motor deficit. Conclusion: Peripheral motor nerve electrostimulation is a simple, easily accessible technique allowing early detection of impending neurologic injury during percutaneous image-guided thermal ablation. It complements existing monitoring techniques and provides a functional assessment along the whole length of the nerve.

  13. Effects of early training and nicotine treatment on the performance of male NMRI mice in the water maze.

    Vicens, Paloma; Carrasco, M Carmen; Redolat, Rosa

    2003-01-01

    This research aimed to evaluate the effect of nicotine treatment and prior training on a spatial learning task in differently aged NMRI male mice. In a longitudinal study, mice were randomly assigned to one of 14 experimental groups receiving different combinations of chronically injected nicotine (0.35 mg/kg) administered for 10 days (5 days before and during 5 days acquisition of task) or control treatments and training in the water maze at different ages. The mice displayed shorter escape latencies when evaluated at 6 and 10 months than when tested in this task at 2 months for the first time, demonstrating that early training preserves performance in the water maze up to 8 months after the initial experience. Nicotine treatment did not significantly change performance in the water maze at any age tested. Early practice in a spatial reference memory task appears to have lasting consequences and can potentially contribute to preventing some age-related spatial learning deficits.

  14. Rapid learning of magnetic compass direction by C57BL/6 mice in a 4-armed 'plus' water maze.

    John B Phillips

    Full Text Available Magnetoreception has been demonstrated in all five vertebrate classes. In rodents, nest building experiments have shown the use of magnetic cues by two families of molerats, Siberian hamsters and C57BL/6 mice. However, assays widely used to study rodent spatial cognition (e.g. water maze, radial arm maze have failed to provide evidence for the use of magnetic cues. Here we show that C57BL/6 mice can learn the magnetic direction of a submerged platform in a 4-armed (plus water maze. Naïve mice were given two brief training trials. In each trial, a mouse was confined to one arm of the maze with the submerged platform at the outer end in a predetermined alignment relative to magnetic north. Between trials, the training arm and magnetic field were rotated by 180(° so that the mouse had to swim in the same magnetic direction to reach the submerged platform. The directional preference of each mouse was tested once in one of four magnetic field alignments by releasing it at the center of the maze with access to all four arms. Equal numbers of responses were obtained from mice tested in the four symmetrical magnetic field alignments. Findings show that two training trials are sufficient for mice to learn the magnetic direction of the submerged platform in a plus water maze. The success of these experiments may be explained by: (1 absence of alternative directional cues (2, rotation of magnetic field alignment, and (3 electromagnetic shielding to minimize radio frequency interference that has been shown to interfere with magnetic compass orientation of birds. These findings confirm that mice have a well-developed magnetic compass, and give further impetus to the question of whether epigeic rodents (e.g., mice and rats have a photoreceptor-based magnetic compass similar to that found in amphibians and migratory birds.

  15. Fractional ablative erbium YAG laser

    Taudorf, Elisabeth H; Haak, Christina S; Erlendsson, Andrés M

    2014-01-01

    BACKGROUND AND OBJECTIVES: Treatment of a variety of skin disorders with ablative fractional lasers (AFXL) is driving the development of portable AFXLs. This study measures micropore dimensions produced by a small 2,940 nm AFXL using a variety of stacked pulses, and determines a model correlating...... laser parameters with tissue effects. MATERIALS AND METHODS: Ex vivo pig skin was exposed to a miniaturized 2,940 nm AFXL, spot size 225 µm, density 5%, power levels 1.15-2.22 W, pulse durations 50-225 microseconds, pulse repetition rates 100-500 Hz, and 2, 20, or 50 stacked pulses, resulting in pulse...... 190 to 347 µm. CONCLUSIONS: Pulse stacking with a small, low power 2,940 nm AFXL created reproducible shallow to deep micropores, and influenced micropore configuration. Mathematical modeling established relations between laser settings and micropore dimensions, which assists in choosing laser...

  16. Dust ablation in Pluto's atmosphere

    Horanyi, Mihaly; Poppe, Andrew; Sternovsky, Zoltan

    2016-04-01

    Based on measurements by dust detectors onboard the Pioneer 10/11 and New Horizons spacecraft the total production rate of dust particles born in the Edgeworth Kuiper Belt (EKB) has been be estimated to be on the order of 5 ṡ 103 kg/s in the approximate size range of 1 - 10 μm. Dust particles are produced by collisions between EKB objects and their bombardment by both interplanetary and interstellar dust particles. Dust particles of EKB origin, in general, migrate towards the Sun due to Poynting-Robertson drag but their distributions are further sculpted by mean-motion resonances as they first approach the orbit of Neptune and later the other planets, as well as mutual collisions. Subsequently, Jupiter will eject the vast majority of them before they reach the inner solar system. The expected mass influx into Pluto atmosphere is on the order of 200 kg/day, and the arrival speed of the incoming particles is on the order of 3 - 4 km/s. We have followed the ablation history as function of speed and size of dust particles in Pluto's atmosphere, and found that volatile rich particles can fully sublimate due to drag heating and deposit their mass in narrow layers. This deposition might promote the formation of the haze layers observed by the New Horizons spacecraft. This talk will explore the constraints on the composition of the dust particles by comparing the altitude of the deposition layers to the observed haze layers.

  17. Percutaneous local ablation of unifocal subclinical breast cancer: clinical experience and preliminary results of cryotherapy

    Manenti, Guglielmo; Perretta, Tommaso; Gaspari, Eleonora; Pistolese, Chiara A.; Scarano, Lia; Cossu, Elsa; Simonetti, Giovanni; Masala, Salvatore [University Hospital ' ' Tor Vergata' ' , Department of Diagnostic Imaging and Interventional Radiology, Molecular Imaging and Radiotherapy, Rome (Italy); Bonanno, Elena [University Hospital ' ' Tor Vergata' ' , Department of Biopathology, Rome (Italy); Buonomo, Oreste C.; Petrella, Giuseppe [University Hospital ' ' Tor Vergata' ' , Department of General Surgery Division, Rome (Italy)

    2011-11-15

    To assess the ablative effectiveness, the oncological and cosmetic efficacy of image-guided percutaneous cryoablation in the treatment of single breast nodules with subclinical dimensions after identification with ultrasonography (US), mammography, magnetic resonance (MRI) and characterization by vacuum assisted biopsy. Fifteen women with a mean age of 73 {+-} 5 years (range 64-82 years) and lesion diameter of 8 {+-} 4 mm were undergoing cryotherapy technology with a single probe under US-guidance associated with intra-procedural lymph-node mapping and excision of the sentinel node. All the patients underwent surgical resection (lumpectomy) from 30 to 45 days after the percutaneous ablation. The iceball size generated by the cryoprobe during the procedure at minus 40 C was 16 x 41 mm. In 14 of the 15 patients was observed a complete necrosis of the cryo-ablated lesion both in post-procedural MRI follow-up and anatomo-pathological evaluation after surgical resection. In one case there was a residual disease in post-procedural MRI and postoperative histological examination, probably justified by an incorrect positioning of the probe. The percutaneous cryoablation as a ''minimally invasive'' technique can provide excellent oncological and cosmetic results on selected cases handled by experienced operators by using the tested devices. (orig.)

  18. Femtosecond laser ablation of silicon in air and vacuum

    Zehua Wu; Nan Zhang; Mingwei Wang; Xiaonong Zhu

    2011-01-01

    Femtosecond (fs) pulse laser ablation of silicon targets in air and in vacuum is investigated using a time-resolved shadowgraphic method. The observed dynamic process of the fs laser ablation of silicon in air is significantly different from that in vacuum. Similar to the ablation of metallic targets, while the shock wave front and a series of nearly concentric and semicircular stripes, as well as the contact front, are clearly identifiable in the process of ablation under 1 x 105 Pa, these phenomena are no longer observed when the ablation takes place in vacuum. Although the ambient air around the target strongly affects the evolution of the ablation plume, the three rounds of material ejection clearly observed in the shadowgraphs of fs laser ablation in standard air can also be distinguished in the process of ablation in vacuum. It is proven that the three rounds of material ejection are caused by different ablation mechanisms.%@@ Femtosecond(fs)pulse laser ablation of silicon targets in air and in vacuum is investigated using a timeresolved shadowgraphic method.The observed dynamic process of the fs laser ablation of silicon in air is significantly different from that in vacuum.Similar to the ablation of metallic targets,while the shock wave front and a series of nearly concentric and semicircular stripes,as well as the contact front,are clearly identifiable in the process of ablation under 1 x 105 Pa,these phenomena are no longer observed when the ablation takes place in vacuum.Although the ambient air around the target strongly affects the evolution of the ablation plume,the three rounds of material ejection clearly observed in the shadowgraphs of fs laser ablation in standard air can also be distinguished in the process of ablation in vacuum.It is proven that the three rounds of material ejection are caused by different ablation mechanisms.

  19. Ablation enhancement of silicon by ultrashort double-pulse laser ablation

    Zhao, Xin; Shin, Yung C. [Center for Laser-Based Manufacturing, School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2014-09-15

    In this study, the ultrashort double-pulse ablation of silicon is investigated. An atomistic simulation model is developed to analyze the underlying physics. It is revealed that the double-pulse ablation could significantly increase the ablation rate of silicon, compared with the single pulse ablation with the same total pulse energy, which is totally different from the case of metals. In the long pulse delay range (over 1 ps), the enhancement is caused by the metallic transition of melted silicon with the corresponding absorption efficiency. At ultrashort pulse delay (below 1 ps), the enhancement is due to the electron excitation by the first pulse. The enhancement only occurs at low and moderate laser fluence. The ablation is suppressed at high fluence due to the strong plasma shielding effect.

  20. Mechanism of Spatiotemporal Distribution of Laser Ablated Materials

    XU Rong-Qing; CUI Yi-Ping; LU Jian; NI Xiao-Wu

    2009-01-01

    Interaction between subsequent laser and ablated materials in laser processing changes the laser spatiotemporal distribution and has influences on the efficiency and quality of laser processing. The theoretical and experimental researches on transportation behayiour of ablated materials are provided. It is shown that the velocity distribution of ablated materials is determined by ablation mechanism. The transportation behaviour of ablated materials is controlled by diffusion mechanism and light field force during laser pulse duration while it is only determined by diffusion mechanism when the laser pulse terminates. In addition, the spatiotemporal distribution of ablated materials is presented.

  1. Laser ablation of hepatocellular carcinoma-A review

    2008-01-01

    A wide range of local thermal ablative therapies have been developed in the treatment of non resectable hepatocellular carcinoma (HCC) in the last decade. Laser ablation (LA) and radiofrequency ablation (RFA) are the two most widely used of these. This article provides an up to date overview of the role of laser ablation in the local treatment of HCC. General principles, technique, image guidance and patient selection are discussed. A review of published data on treatment efficacy, long term outcome and complication rates of laser ablation is included and comparison with RFA made. The role of laser ablation in combination with transcatheter arterial chemoembolisation is also discussed.

  2. Materialising power struggles of political imprisonment at Long Kesh/Maze prison, Northern Ireland

    McAtackney, Laura

    2015-01-01

    Prisons were one of the main arenas for contestation of rights, status and power during the course of the Northern Irish Troubles (c1969-c1998). A substantial number of the prisoners publicly denied the legitimacy of the state to imprison them and all those interned, remanded or convicted...... for paramilitary-related offences claimed political status. When a prison body communalises and actively contests its imprisonment the resulting power struggle become one of the most explicit witnessed in modern, capitalist societies. This paper explores Long Kesh/Maze prison, one of the seminal places...... of imprisonment during the conflict. It was a site where a number of major events emanated from, often catalyzing responses in wider society, as well as being the source of ongoing issues with ‘non-complying’ prisoners. It was a constant source of anxiety for the Northern Ireland and British governments...

  3. Sex differences in ICR mice in the Morris water maze task.

    Ge, J F; Qi, C C; Qiao, J P; Wang, C W; Zhou, N J

    2013-01-01

    The Morris water maze (MWM) is one of the most common tasks used to assess spatial learning and memory ability in rodents. Genetic strain and gender are two prominent variants that influence spatial performance. Although it was reported that ICR (Institute of Cancer Research) mice exhibited an unchanged baseline performance in the training phase of the MWM task, this outbred strain has been widely used in learning and memory studies, and little is known regarding the effects of sex on behavioral performance. In this study, we demonstrated that both male and female ICR mice could complete the MWM task. Furthermore, a significant sex difference was observed, with females having shorter escape latencies and longer durations in the target quadrant in both the acquisition and test phases. Our findings emphasize the necessity of careful examination of not only the strain effect on behavioral performance but also the sex effect.

  4. Habituation under stress: shocked mice show nonassociative learning in a T-maze.

    Mitchell, D; Osborne, E W; O'Boyle, M W

    1985-03-01

    Conflicting predictions of reinforcement and neophobia-arousal theories were evaluated in a simple choice task. Four groups of C57BL/6J mice were administered daily two-trial tests in a uniform T-maze for 10 consecutive days. For three groups, the contingencies of footshock treatments were manipulated to reinforce alternation, perseveration, or both. A control group that was not administered footshock alternated, but all three groups that were stressed perseverated more and more across tests, despite the differences in reinforcement contingencies. These results are inconsistent with the predictions of reinforcement theory but consistent with the view that stressed or aroused animals are neophobic and use nonassociative learning (habituation) to distinguish between novel and familiar alternatives.

  5. Decoding the view expectation during learned maze navigation from human fronto-parietal network.

    Shikauchi, Yumi; Ishii, Shin

    2015-12-03

    Humans use external cues and prior knowledge about the environment to monitor their positions during spatial navigation. View expectation is essential for correlating scene views with a cognitive map. To determine how the brain performs view expectation during spatial navigation, we applied a multiple parallel decoding technique to functional magnetic resonance imaging (fMRI) when human participants performed scene choice tasks in learned maze navigation environments. We decoded participants' view expectation from fMRI signals in parietal and medial prefrontal cortices, whereas activity patterns in occipital cortex represented various types of external cues. The decoder's output reflected participants' expectations even when they were wrong, corresponding to subjective beliefs opposed to objective reality. Thus, view expectation is subjectively represented in human brain, and the fronto-parietal network is involved in integrating external cues and prior knowledge during spatial navigation.

  6. Atrio-oesophageal fistula after transcatheter radiofrequency ablation.

    Moss, Caroline E; Fernandez-Caballero, Sandra; Walker, David

    2015-01-05

    A 68-year-old woman presented 3 weeks following unsuccessful transcatheter radiofrequency ablation (TcRFA) for treatment of her chronic atrial fibrillation. Neurological signs manifested on day 2 of admission with generalised tonic-clonic seizures and reduced Glasgow Coma Score. She was treated for presumed central nervous system (CNS) infection, intubated and transferred to the intensive care unit. CT of the head showed bilateral oedema secondary to acute embolic stroke. Blood cultures grew Streptococcus viridans, and lumbar puncture findings were consistent with CNS infection. Echocardiography showed only a septostomy puncture from the atrial fibrillation ablation procedure. Thoracic CT demonstrated air in the left atrium, consistent with the diagnosis of atrio-oesophageal fistula, a rarely reported iatrogenic complication of TcRFA. MRI of the head showed significant neurological injury with innumerable embolic infarcts. After discussion with her family regarding the significant neurological insult, and with no signs of any clinical improvement, the patient died on day 8 of admission.

  7. Ultrasonography guided percutaneous radiofrequency ablation for hepatic cavernous hemangioma

    Yan Cui; Hong-Wen Zhang; Li-Yan Zhou; Man-Ku Dong; Ping Wang; Min Ji; Xiao-Ou Li; Chang-Wei Chen; Zi-Pei Liu; Yong-Jie Xu

    2003-01-01

    AIM: Hepatic cavernous hemangioma (HCH) is the mostcommon benign tumor of the liver and its management isstill controversial. Recent successin situ radiofrequencyablation of hepatic malignancies has led us to consider usingthis technique in patients with HCH. This study was to assessthe efficacy, safety, and complications of percutaneousradiofrequency ablation (PRFA) under ultrasonographyguidance in patients with HCH.METHODS: Twelve patients (four men and eight women,age ranged 33-56 years, mean age was 41.7 years) with 15hepatic cavernous hemangiomas (2.5 cm to 9.5 cm) weretreated using the RF-2000 generator and 10-needle LeVeenelectrode percutaneously guided by B-ultrasound. Lesionslarger than 3 cm were treated by multiple overlappingablations that encompass the entire lesion as well as a rimof normal liver tissue (approximately 0.5 cm).RESULTS: All the patients who received PRFA therapy hadno severe pain, bleeding or bile leakage during and afterthe procedures. Nine to 34 months′ follow-up (mean, 21months) by ultrasound and/or spiral CT scan demonstratedthat the ablated lesions in this group were shrunk remarkably,and the shrunken range was 38-79 % (mean, 67 % per 21months). The contrast enhancement was disappeared withinthe tumor or at its periphery in all cases on spiral CT scansobtained 3 to 6 months after treatment.CONCLUSION: The results of this study suggest that PRFAtherapy is a mini-invasive, simple, safe, and effective methodfor the treatment of selected patients with HCH.

  8. Technology update: bronchoscopic thermal vapor ablation for managing severe emphysema

    Gompelmann D

    2014-09-01

    Full Text Available Daniela Gompelmann,1,2 Ralf Eberhardt,1,2 Felix JF Herth1,21Pneumology and Critical Care Medicine, Thoraxklinik at University of Heidelberg, 2German Center for Lung Research, Heidelberg, GermanyAbstract: Bronchoscopic thermal vapor ablation (BTVA is an endoscopic lung volume reduction therapy that presents an effective treatment approach in patients with severe upper lobe-predominant emphysema. By instillation of heated water vapor, an inflammatory reaction is induced, leading to fibrosis and scarring of the lung parenchyma, resulting in lobar volume reduction. Clinical single-arm trials demonstrated great outcomes, with significant improvement of lung function, exercise capacity, and quality of life. As the BTVA-induced local inflammatory response that seems to be essential for the desired lobar volume reduction can be associated with transient clinical worsening, strict monitoring of the patients is required. In future, the balance between efficacy and safety will constitute a major challenge. This review summarizes the BTVA procedure, the mechanism of action, and the results of the clinical trials, including the efficacy and safety data.Keywords: emphysema, bronchoscopy, bronchoscopic thermal vapor ablation

  9. Learning about cognition risk with the radial-arm maze in the developmental neurotoxicology battery.

    Levin, Edward D

    2015-01-01

    Cognitive dysfunction has been found in epidemiological studies to be among the most sensitive impairments associated with developmental exposure to a variety of environmental contaminants from heavy metals to polyhalogenated hydrocarbons and pesticides. These chemicals have been also shown to impair cognitive function after developmental exposure in experimental animal models. The radial-arm maze (RAM) has proven to be a sensitive and reliable way to assess both learning and memory in a variety of species, most often in rats and mice. The RAM is a very adaptable test method that takes advantage of rodents' instinct to explore new places in the environment to forage. That is, rodents do not need to be trained to run through the maze; they will normally do this from the initial session of testing. Training with differential reinforcement for arm choices provides a more rigorous test of learning and memory. The RAM is quite adaptable for assessing various aspects of cognition. Although the RAM has been mostly used to assess spatial learning and memory, it can be configured to assess non-spatial memory as well. Both working and reference memory can be easily distinguished. The RAM can be run with both appetitive (food reinforced) and aversive (water escape) motivators. The RAM has been found to be sensitive to a wide variety of developmental toxicants including heavy metals such as mercury and pesticides such as chlorpyrifos. There is an extremely rich literature especially with rats showing the effects of many types of brain lesions and drug effects so that the participation of a wide variety of neural systems in RAM performance is known. These systems, notably the hippocampus and frontal cortex, and acetylcholine and glutamate neurotransmitter systems, are the same neural systems that have been shown in humans to be critical for learning and memory. This considerably aids the interpretation of neurobehavioral toxicity studies.

  10. Development and validation of a sensitive entropy-based measure for the water maze

    Hamid R Maei

    2009-12-01

    Full Text Available In the water maze, mice are trained to navigate to an escape platform located below the water’s surface, and spatial learning is most commonly evaluated in a probe test in which the platform is removed from the pool. While contemporary tracking software provides precise positional information of mice for the duration of the probe test, existing performance measures (e.g., percent quadrant time, platform crossings fail to exploit fully the richness of this positional data. Using the concept of entropy [H], here we develop a new measure that considers both how focused the search is and the degree to which searching is centered on the former platform location. To evaluate how H performs compared to existing measures of water maze performance we compiled 5 separate databases, containing more than 1600 mouse probe tests. Random selection of individual trials from respective databases then allowed us to simulate experiments with varying sample and effect sizes. Using this Monte Carlo-based method, we found that H outperformed existing measures in its ability to detect group differences over a range of sample or effect sizes. Additionally, we validated the new measure using three models of experimentally-induced hippocampal dysfunction: 1 complete hippocampal lesions, 2 genetic deletion of αCaMKII, a gene implicated in hippocampal behavioral and synaptic plasticity, and 3 a mouse model of Alzheimer’s disease. Together, these data indicate that H offers greater sensitivity than existing measures, most likely because it exploits the richness of the precise positional information of the mouse throughout the probe test.

  11. Effects of prenatal methylazoxymethanol acetate (MAM) treatment in rats on water maze performance.

    Leng, Andreas; Jongen-Rêlo, Ana L; Pothuizen, Helen H J; Feldon, Joram

    2005-06-20

    Prenatal methylazoxymethanol acetate (MAM) treatment has been shown to induce morphological abnormalities in cortical areas of the offspring. Based on the neuroanatomical and behavioural abnormalities, this treatment has been suggested as a useful animal model for schizophrenia. In a previous study (Jongen-Relo AL, Leng A, Luber M, Pothuizen HHJ, Weber L, Feldon J. The prenatal methylazoxymethanol acetate treatment: a neurodevelopmental animal model for schizophrenia? Behav Brain Res 2004;149:159-81) we have studied MAM-treated animals in a series of behavioural tests related to schizophrenia, such as latent inhibition and pre-pulse inhibition of the acoustic startle response to establish the validity of prenatal MAM treatment (20mg/kg i.p. on gestational days 9-15; MAM 9-MAM 15). We found that, apart from a marginal effect of increased activity in the open field, the MAM treatment on gestational day 15 was behaviourally ineffective. Here, we extended our previous study to a water maze experiment conducted in the same batch of animals as presented previously (MAM 12-MAM 15). MAM-treated animals showed similar water maze performance compared with control animals during the acquisition phase and the probe tests. However, during the reversal phase, MAM 15 animals showed impaired acquisition of the new platform location. This might indicate some cognitive deficits in MAM 15 animals in terms of working memory or behavioural flexibility. However, in combination with the lack of behavioural abnormalities of MAM 12-MAM 15 animals in several other tests related to schizophrenia in the previously reported study, the use of MAM treatment (MAM 12-MAM 15) as a valid model for schizophrenia still remains debatable.

  12. Validation of an automated system for measuring anxiety-related behaviours in the elevated plus maze.

    Sidor, Michelle M; Rilett, Kelly; Foster, Jane A

    2010-04-30

    The elevated plus maze (EPM) is one of the most widely used and established tests to assess anxiety-related behaviours and has been validated for use in both mice and rats. Although relatively quick and simple to conduct, there always exists the potential for observer bias during data collection. The KinderScientific EPM system uses a series of apparatus-embedded photobeams to collect spatiotemporal measures such as the amount of time spent in each zone of the maze (centre, open and closed arms), and the frequency of arm entries. Risk assessment behaviours, such as head dips and protected stretches, are also measured which represents a unique feature of this system over other automated EPM systems. We compared observer derived spatiotemporal and risk assessment measurements with automated generated data to test the reliability and accuracy of the automated system. Data were manually collected using different zone entry/exit criteria (2 vs. 4 paws). Automated data were generated using both the default zone map provided with the system and a user-modified zone map. We show that the automated EPM provides accurate and reliable measurements of both spatiotemporal and risk assessment behaviours. In addition, we show that the default zone map overestimated visually observed arm entries while our modified zone map generated data comparable to manually generated data using a 4 paws open arm entry criteria which is most consistently used to define arm entry in the literature. The KinderScientific automated EPM system represents a reliable tool for collection of a wide range of anxiety-related behavioural measures.

  13. Effects of apomorphine on rat behavior in the elevated plus-maze.

    Garcia, Andrea Milena Becerra; Martinez, Raquel; Brandão, Marcus Lira; Morato, Silvio

    2005-07-21

    It has been reported that novelty may evoke both an exploratory and a fear drive, thus generating behavior responding to an approach/avoidance conflict. However, not much is known about the approach component. Whereas there exists abundant evidence referring to the avoidance component as the main target for the anxiolytic action of benzodiazepines, the involvement of dopaminergic mechanisms in fear and anxiety is controversial. The present study examined the effects of the dopaminergic agonist apomorphine, the D(2) dopaminergic antagonist sulpiride and the combined treatment sulpiride plus apomorphine on conventional and non-conventional measures of the behavior of rats exposed to an elevated plus-maze. Systemic injection of apomorphine (0.25, 0.5 and 1.0 mg/kg) caused a selective increase in the time spent in the open arms and in the open arm extremities. Pre-treatment with sulpiride blocked these effects while this dopaminergic antagonist had no effect by its own. Apomorphine produced no significant effects on stretching, flat-back-approach or scanning. Therefore, apomorphine increased the behavioral response linked to the approach component of the conflict without affecting risk assessment behaviors. These findings suggest that dopaminergic mechanisms, probably through D(2) receptors, may also be involved in the mediation of the conflict derived from the need of gathering information for confirming, identifying and localizing danger and take the appropriate action for avoiding the threatening stimuli of the elevated plus-maze. A role for dopaminergic mechanisms in the setting up of adaptive responses in a fear-inducing environment is discussed.

  14. Use of maze in cyclotron hoppers; Utilizacao de labirinto em bunker de ciclotron

    Fernandes, Fernando A.; Alves, Juliano S.; Fochesatto, Cintia; Cerioli, Luciane; Borges, Joao Alfredo; Gonzalez, Delfin; Silva, Daniel C., E-mail: fernandofernandes@biofarmaco.com.br [Delfin Farmacos e Derivados (Biofarmaco Marcadores Moleculares), Lauro de Freitas, BA (Brazil)

    2013-07-01

    Introduction: the increasing number of cyclotrons in Brazil due to constitutional amendment 49 /06 that enabled the production of radiopharmaceuticals with a short half - life by private companies. The radionuclides used for PET - CT require production centers near or within the diagnostic centers. In order to minimize maintenance and operating risks, gaining efficiency, our facility was the first in Brazil to use the access to a cyclotron bunker via maze, rather than armored door stopper type. Materials: the design calculations were based on the Monte Carlo method (MCNP5 - Monte Carlo N-Particletransportcode version 5). At the ends of the labyrinth are installed a door of polyethylene, for thermalization of neutrons, and other of wood for limiting access. Both legs of the maze have wall thickness of 100cm. In inspection Brazilian CNEN realize measures of dose rate for neutrons and gamma 9 points: 7 around the bunker, 1 over the bunker and 1 in the exhaust with the cyclotron operating with maximum load, double beam of 50uA for 2 hours. After commissioning were carried out around the bunker, the following measures: cumulative dose in three months with dosimeters for neutron rate dose with a gas proportional detector type filled with {sup 3}He and polyethylene neutron moderator and dose rate with a Geiger - Mueller detector for gamma radiation. Readings with neutron detectors were classified as background radiation and dose rates were always below the limits established in standard EN 3.01, and the calculation of the predicted regardless of the intensity of irradiation inside the bunker. Conclusion: the use of labyrinths as a way to access the bunkers cyclotron has been shown to be effective as the radiation shielding and efficient by allowing quick and easy access, virtually eliminating the maintenance.

  15. Microwave Ablation of Pulmonary Malignancies Using a Novel High-energy Antenna System

    Little, Mark W.; Chung, Daniel; Boardman, Philip; Gleeson, Fergus V.; Anderson, Ewan M., E-mail: ewan.anderson@ouh.nhs.uk [Churchill Hospital, Department of Radiology (United Kingdom)

    2013-04-15

    To evaluate the technical success, safety, and imaging follow-up of malignant pulmonary nodules treated with a novel high-energy percutaneous microwave ablation (MWA) system. Between July 2010 and September 2011, a total of 23 patients, 12 men, mean age 68 (range 30-87) years with 29 pulmonary malignancies of median diameter 19 (range 8-57) mm, underwent computed tomography (CT)-guided MWA with a 16G microwave needle antenna enabling power up to 180 W. Technical success was defined as needle placement in the intended lesion without death or serious injury. Adequacy of ablation was assessed at 24 h on contrast-enhanced CT. Circumferential solid or ground glass opacification >5 mm was used to define an ideal ablation. Local tumor recurrence was assessed at 1, 3, and 6 months after ablation on contrast-enhanced CT. MWA was technically successful in 93 % (n = 27). Mean ablation duration was 3.6 (range 1-9) min. Ten patients (43 %) developed a pneumothorax as a result of the MWA; only 3 (13 %) required placement of a chest drain. Thirty-day mortality rate was 0 %. The mean hospital stay was 1.5 (range 1-7) days. A total of 22 lesions (75 %) were surrounded by {>=}5 mm ground glass or solid opacification after the procedure. At a median follow-up of 6 months, local recurrence was identified in 3 out of 26 lesions, giving a local control rate of 88 %. MWA using a high-power antenna of pulmonary malignancies is safe, technically achievable, and enables fast ablation times.

  16. Ultrasonography-guided percutaneous radiofrequency ablation for cervical lymph node metastasis from thyroid carcinoma

    Liping Wang

    2014-01-01

    Full Text Available Purpose: The aim was to explore the efficacy and safety of ultrasonography-guided percutaneous radiofrequency ablation (RFA for cervical lymph node metastases from thyroid carcinoma. Materials and Methods: Eight patients with previous total thyroidectomy and radioiodine therapy were enrolled in this study. A total of 20 cervical lymph node metastases were confirmed by percutaneous biopsy. Participants underwent ultrasonography-guided RFA treatment for all confirmed metastatic lymph nodes. Contrast-enhanced ultrasound (CEUS and sonoelastography were performed to rapidly evaluate treatment responses before and shortly after RFA. Routine follow-up consisted of conventional US, CEUS, sonoelastography, thyroglobulin level, and necessary fine needle aspiration cytology. Results: All eight patients were successfully treated without obvious complications. Post-RFA CEUS showed that total metastatic lymph nodes were ablated. The sonoelastographic score of ablated area elevated significantly shortly after RFA (P < 0.001. With a mean follow-up of 9.4 ± 5.1 months, there were no evidences of recurrence at ablated sites; however, two new cervical recurrent lymph nodes occurred in one case, which was successfully ablated as well. The mass volume shrinkages of the ablated nodes were observed in all cases. We found that 5 treated lymph nodes disappeared, 4 were reduced more than 80%, 9 were reduced between 50% and 80%, and 2 were reduced less than 50%. At the last follow-up evaluation, the serum thyroglobulin levels had decreased in 6 of 8 patients. Conclusion: Ultrasonography-guided percutaneous RFA for cervical lymph node metastasis of thyroid malignancy is a feasible, effective, and safe therapy. This procedure shows a nonsurgical therapeutic option for metastatic lymph nodes in patients with difficult reoperations or inoperations, it may reduce or delay a large number of highly invasive repeated neck dissections.

  17. Fundamental studies of pulsed laser ablation

    Claeyssens, F

    2001-01-01

    dopant) have resulted in a coherent view of the resulting plume, which exhibits a multi-component structure correlated with different regimes of ablation, which are attributed to ejection from ZnO and ablation from a Zn melt. OES measurements show that the emitting Zn component within the plume accelerates during expansion in vacuum - an observation attributable to the presence of hot, fast electrons in the plume. The same acceleration behaviour is observed in the case of Al atomic emissions resulting from ablation of an Al target in vacuum. Deposition conditions, substrate temperature and background gas pressure were all varied in a quest for optimally aligned, high quality ZnO thin films. Initial ab initio calculations were performed also, to aid in understanding the stability of these c-axis aligned films. The pulsed ultraviolet (lambda = 193, 248 nm) laser ablation of graphite, polycrystalline diamond and ZnO targets has been investigated. Characteristics of the resulting plumes of ablated material have b...

  18. Percutaneous tumor ablation in medical radiology

    Vogl, T.J.; Mack, M.G. [University Hospital Frankfurt Univ. (Germany). Inst. for Diagnostic and Interventional Radiology; Helmberger, T.K. [Klinikum Bogenhausen, Academic Teaching Hospital of the Technical Univ. Munich (Germany). Dept. for Diagnostic and Interventional Radiology and Nuclear Medicine; Reiser, M.F. (eds.) [University Hospitals - Grosshadern and Innenstadt Munich Univ. (Germany). Dept. of Clinical Radiology

    2008-07-01

    Thermal ablation has become an integral part of oncology, especially in the field of interventional oncology. This very comprehensive book encompasses the different technologies employed in thermal ablation, its indications and the results achieved in various clinical conditions. The first part of the book clearly explains the basics of thermal ablative techniques such as laser-induced thermotherapy, radiofrequency ablation, microwave ablation, cryotherapy, and localized tumor therapy. The latest developments in the application of minimally invasive therapies in localized neoplastic disease are demonstrated. In the main part of the book, techniques of guiding the applicators to the target structures by use of different imaging tools such as ultrasound, computed tomography and magnetic resonance imaging are discussed. The results are presented for a variety of clinical indications, including liver and lung tumors and metastases and some rather rare conditions involving the kidney, the head and neck, the prostate, and soft tissue structures. A large number of acknowledged experts have contributed to the book, which benefits from a lucid structure and excellent images. (orig.)

  19. Case of Successful Mapping of Epicardial Surface of the Basal Part of the Left Ventricle during Ventricular Tachyarrhythmia Radiofrequency Ablation

    Bockeria L. A.

    2012-09-01

    rhythm and complete elimination of symptomatic ventricular tachyarrhythmiae. Disadvantages of this procedure: possible complications (hemopericardium, precordialgiae, acute myocardial infarction, absence of 100% possibility to use radiofrequency ablation because of supposed arrhythmogenic area of coronary arteries and epicardial body fat; besides, there are the cases of intramyocardial position of ectopic activity.

  20. Ablation for atrial fibrillation during mitral valve surgery: 1-year results through continuous subcutaneous monitoring†

    Bogachev-Prokophiev, Alexandr; Zheleznev, Sergey; Romanov, Alexander; Pokushalov, Evgeny; Pivkin, Alexey; Corbucci, Giorgio; Karaskov, Alexander

    2012-01-01

    Continuous monitoring of cardiac rhythm may play an important role in measuring the true symptomatic/asymptomatic atrial fibrillation (AF) burden and improve the management of anti-arrhythmic and anti-thrombotic therapies. Forty-seven patients with mitral valve disease and longstanding persistent AF (LSPAF) underwent a left atrial maze procedure with bipolar radiofrequency and valve surgery. The follow-up data recorded by an implanted loop recorder were analysed after 3, 6 and 12 months. On discharge, 40 (85.1%) patients were in stable sinus rhythm, as documented by in-office electrocardiography (ECG), 4 (8.5%) were in pacemaker rhythm and 3 (6.4%) were in AF. One (2.1%) patient died after 7 months. On 12-month follow-up examination, 30 (65.2%) patients had an AF burden 0.5%. Two (4.3%) patients with AF recurrences were completely asymptomatic. Among the symptomatic events stored by the patients, only 27.6% was confirmed as genuine AF recurrences according to the concomitant ECG recorded by the implanted loop recorder. A concomitant bipolar maze procedure during mitral valve surgery is effective in treating AF, as proved by detailed 1-year continuous monitoring. PMID:22514258

  1. Ablation for atrial fibrillation during mitral valve surgery: 1-year results through continuous subcutaneous monitoring.

    Bogachev-Prokophiev, Alexandr; Zheleznev, Sergey; Romanov, Alexander; Pokushalov, Evgeny; Pivkin, Alexey; Corbucci, Giorgio; Karaskov, Alexander

    2012-07-01

    Continuous monitoring of cardiac rhythm may play an important role in measuring the true symptomatic/asymptomatic atrial fibrillation (AF) burden and improve the management of anti-arrhythmic and anti-thrombotic therapies. Forty-seven patients with mitral valve disease and longstanding persistent AF (LSPAF) underwent a left atrial maze procedure with bipolar radiofrequency and valve surgery. The follow-up data recorded by an implanted loop recorder were analysed after 3, 6 and 12 months. On discharge, 40 (85.1%) patients were in stable sinus rhythm, as documented by in-office electrocardiography (ECG), 4 (8.5%) were in pacemaker rhythm and 3 (6.4%) were in AF. One (2.1%) patient died after 7 months. On 12-month follow-up examination, 30 (65.2%) patients had an AF burden 0.5%. Two (4.3%) patients with AF recurrences were completely asymptomatic. Among the symptomatic events stored by the patients, only 27.6% was confirmed as genuine AF recurrences according to the concomitant ECG recorded by the implanted loop recorder. A concomitant bipolar maze procedure during mitral valve surgery is effective in treating AF, as proved by detailed 1-year continuous monitoring.

  2. Fiber-Optic Temperature and Pressure Sensors Applied to Radiofrequency Thermal Ablation in Liver Phantom: Methodology and Experimental Measurements

    Daniele Tosi

    2015-01-01

    Full Text Available Radiofrequency thermal ablation (RFA is a procedure aimed at interventional cancer care and is applied to the treatment of small- and midsize tumors in lung, kidney, liver, and other tissues. RFA generates a selective high-temperature field in the tissue; temperature values and their persistency are directly related to the mortality rate of tumor cells. Temperature measurement in up to 3–5 points, using electrical thermocouples, belongs to the present clinical practice of RFA and is the foundation of a physical model of the ablation process. Fiber-optic sensors allow extending the detection of biophysical parameters to a vast plurality of sensing points, using miniature and noninvasive technologies that do not alter the RFA pattern. This work addresses the methodology for optical measurement of temperature distribution and pressure using four different fiber-optic technologies: fiber Bragg gratings (FBGs, linearly chirped FBGs (LCFBGs, Rayleigh scattering-based distributed temperature system (DTS, and extrinsic Fabry-Perot interferometry (EFPI. For each instrument, methodology for ex vivo sensing, as well as experimental results, is reported, leading to the application of fiber-optic technologies in vivo. The possibility of using a fiber-optic sensor network, in conjunction with a suitable ablation device, can enable smart ablation procedure whereas ablation parameters are dynamically changed.

  3. Evaluation of left ventricular scar identification from contrast enhanced magnetic resonance imaging for guidance of ventricular catheter ablation therapy

    Rettmann, M. E.; Lehmann, H. I.; Johnson, S. B.; Packer, D. L.

    2016-03-01

    Patients with ventricular arrhythmias typically exhibit myocardial scarring, which is believed to be an important anatomic substrate for reentrant circuits, thereby making these regions a key target in catheter ablation therapy. In ablation therapy, a catheter is guided into the left ventricle and radiofrequency energy is delivered into the tissue to interrupt arrhythmic electrical pathways. Low bipolar voltage regions are typically localized during the procedure through point-by-point construction of an electroanatomic map by sampling the endocardial surface with the ablation catheter and are used as a surrogate for myocardial scar. This process is time consuming, requires significant skill, and has the potential to miss low voltage sites. This has led to efforts to quantify myocardial scar preoperatively using delayed, contrast-enhanced MRI. In this paper, we evaluate the utility of left ventricular scar identification from delayed contrast enhanced magnetic resonance imaging for guidance of catheter ablation of ventricular arrhythmias. Myocardial infarcts were created in three canines followed by a delayed, contrast enhanced MRI scan and electroanatomic mapping. The left ventricle and myocardial scar is segmented from preoperative MRI images and sampled points from the procedural electroanatomical map are registered to the segmented endocardial surface. Sampled points with low bipolar voltage points visually align with the segmented scar regions. This work demonstrates the potential utility of using preoperative delayed, enhanced MRI to identify myocardial scarring for guidance of ventricular catheter ablation therapy.

  4. Lingual tonsil hypertrophy causing severe dysphagia: treatment with plasma-mediated radiofrequency-based ablation (Coblation).

    Mowry, Sarah E; Ament, Marvin; Shapiro, Nina L

    2010-03-01

    Lingual tonsil hypertrophy is an uncommon cause of upper aerodigestive tract pathology. We present the case of a 17-year-old boy who developed severe dysphagia and subsequent weight loss as a result of lingual tonsil hypertrophy. He was successfully treated with plasma-mediated radiofrequency-based ablation (Coblation). In the past, traditional surgical procedures for lingual tonsil hypertrophy were difficult to perform and recovery was difficult, but the introduction of Coblation has made lingual tonsillectomy much easier.

  5. Percutaneous Management of a Bronchobiliary Fistula after Radiofrequency Ablation in a Patient with Hepatocellular Carcinoma

    Yoon, Dok Hyun; Shim, Ju Hyun; Lee, Wook Jin; Kim, Pyo Nyun; Shin, Ji Hoon; Kim, Kang Mo [Asan Medical Center, Seoul (Korea, Republic of)

    2009-08-15

    Radiofrequency ablation (RFA) is a minimally invasive, image-guided procedure for the treatment of hepatic tumors. While RFA is associated with relatively low morbidity, sporadic bronchobiliary fistulae due to thermal damage may occur after RFA, although the incidence is rare. We describe a patient with a bronchobiliary fistula complicated by a liver abscess that occurred after RFA. This fistula was obliterated after placement of an external drainage catheter into the liver abscess for eight weeks.

  6. Learning Strategy Selection in the Water Maze and Hippocampal CREB Phosphorylation Differ in Two Inbred Strains of Mice

    Sung, Jin-Young; Goo, June-Seo; Lee, Dong-Eun; Jin, Da-Qing; Bizon, Jennifer L.; Gallagher, Michela; Han, Jung-Soo

    2008-01-01

    Learning strategy selection was assessed in two different inbred strains of mice, C57BL/6 and DBA/2, which are used for developing genetically modified mouse models. Male mice received a training protocol in a water maze using alternating blocks of visible and hidden platform trials, during which mice escaped to a single location. After training,…

  7. Egocentric virtual maze learning in adult survivors of childhood abuse with dissociative disorders: evidence from functional magnetic resonance imaging.

    Weniger, Godehard; Siemerkus, Jakob; Barke, Antonia; Lange, Claudia; Ruhleder, Mirjana; Sachsse, Ulrich; Schmidt-Samoa, Carsten; Dechent, Peter; Irle, Eva

    2013-05-30

    Present neuroimaging findings suggest two subtypes of trauma response, one characterized predominantly by hyperarousal and intrusions, and the other primarily by dissociative symptoms. The neural underpinnings of these two subtypes need to be better defined. Fourteen women with childhood abuse and the current diagnosis of dissociative amnesia or dissociative identity disorder but without posttraumatic stress disorder (PTSD) and 14 matched healthy comparison subjects underwent functional magnetic resonance imaging (fMRI) while finding their way in a virtual maze. The virtual maze presented a first-person view (egocentric), lacked any topographical landmarks and could be learned only by using egocentric navigation strategies. Participants with dissociative disorders (DD) were not impaired in learning the virtual maze when compared with controls, and showed a similar, although weaker, pattern of activity changes during egocentric learning when compared with controls. Stronger dissociative disorder severity of participants with DD was related to better virtual maze performance, and to stronger activity increase within the cingulate gyrus and the precuneus. Our results add to the present knowledge of preserved attentional and visuospatial mnemonic functioning in individuals with DD.

  8. Fear-potentiation in the elevated plus-maze test depends on stressor controllability and fear conditioning

    Korte, S M; Bohus, B; de Boer, Sietse

    1999-01-01

    The purpose of the study was to determine which stressor qualities (escapable vs. inescapable stress and unconditioned vs. conditioned stress) can potentiate fear in the elevated plus-maze. While inescapable stress potentiated fear, escapable stress did not, but escapable stress increased the locomo

  9. The Canine Sand Maze: An Appetitive Spatial Memory Paradigm Sensitive to Age-Related Change in Dogs

    Salvin, Hannah E.; McGreevy, Paul D.; Sachdev, Perminder S.; Valenzuela, Michael J.

    2011-01-01

    Aged dogs exhibit a spectrum of cognitive abilities including a syndrome similar to Alzheimer's disease. A major impediment to research so far has been the lack of a quick and accurate test of visuospatial memory appropriate for community-based animals. We therefore report on the development and validation of the Canine Sand Maze. A 4.5-m-diameter…

  10. Classification Accuracy of Oral Reading Fluency and Maze in Predicting Performance on Large-Scale Reading Assessments

    Decker, Dawn M.; Hixson, Michael D.; Shaw, Amber; Johnson, Gloria

    2014-01-01

    The purpose of this study was to examine whether using a multiple-measure framework yielded better classification accuracy than oral reading fluency (ORF) or maze alone in predicting pass/fail rates for middle-school students on a large-scale reading assessment. Participants were 178 students in Grades 7 and 8 from a Midwestern school district.…

  11. Patients’ survival in lung malignancies treated by microwave ablation: our experience on 56 patients

    Belfiore, G.; Ronza, F. [Department of Diagnostic Imaging, “S. Anna-S. Sebastiano” Hospital, Via F. Palasciano, 81100 Caserta (Italy); Belfiore, M.P., E-mail: mariapaola.belfiore@virgilio.it [Institute of Radiology, Second University of Naples, Piazza Miraglia, 80138 Naples (Italy); Serao, N.; Di Ronza, G. [Department of Diagnostic Imaging, “S. Anna-S. Sebastiano” Hospital, Via F. Palasciano, 81100 Caserta (Italy); Grassi, R.; Rotondo, A. [Institute of Radiology, Second University of Naples, Piazza Miraglia, 80138 Naples (Italy)

    2013-01-15

    Objectives: We retrospectively evaluated percutaneous CT-guided microwave (MW) ablation safety and efficacy in unresectable lung malignancies focusing on patients’ survival. Materials and methods: All procedures were approved by the hospital ethical committee. From 2008 to 2012 we treated 69 unresectable lesions (44 lung cancer, 25 lung metastases) in 56 patients (35 men/21 women; mean age: 61.5 years). Treatment was performed under CT guidance using 14 G needles with a 3 cm active tip and a 55 W MW generator (Vivawave Microwave Coagulation System; Valley Lab). Treatment was performed at 45 W for 6–10 min. Patients were scheduled for a 3 and 6 month CT follow-up to evaluate lesion diameter and enhancement. Survival rate was evaluated by Kaplan–Meier analysis. Results: Ablation procedures were completed according to protocol in all patients. Pneumothorax occurred in 18 patients and 8 required chest tube. Four lesions (all >4.3 cm) were retreated 20 days after the ablation because of peripheral focal areas of residual tumor. Follow-up CT evaluation showed a decrease in maximum diameter in 44/69 lesions (64%) and in 42/59 lesions (71%) at 3 and 6 months, respectively. In all cases no pathologic enhancement was observed. Cancer-specific mortality yielded a survival rate of 69% at 12 months, 54% at 24 months and 49% at 36 months, respectively. An estimate mean for survival time was 27.8 months with a standard error of 2.8 months (95% confidence interval: 22.4–33.2 months). Conclusion: Based on our experience, MW ablation seems to represent a potential safe and effective percutaneous technique in the treatment of lung malignancies. MW ablation may improve survival in patients not suitable to surgery.

  12. Radiofrequency Ablation Mapping with Circumferential Catheter for Paroxys-mal Atrial Fibrillation Originating From the Pulmonary Veins

    刘震; 吴书林; 杨平珍; 方咸宏; 李海杰; 陈泗林; 詹贤章; 薛玉梅

    2002-01-01

    Objectives To assessed thefeasibility and effectiveness of electrophysiologicalmapping of pulmonary veins with a circumferential 10-electrode catheter and radiofrequency catheter abla-tion therapy for patients with paroxysmal atrial fibril-lation. Background Standard mapping and ablationof focal sources of atrial fibrillation are associated withvery long procedure times and low efficacy. Mappingand ablation pulmonary veins guide with a circularcatheter could overcome these limitations. Methods16 patients [male 11, female 5, mean age (51 +14.5) years] with paroxysmal atrial fibrillation refrac-tory to antiarrhythmic drugs were included in thisgroup. A circumferential 10-electrode catheter wasused to pulmonary vein mapping during sinus rhythm orCSd pacing to determine the origin of atrial prematurecontractions. When the ablative target pulmonary veinwas found, the pulmonary vein potentials' distributionand activation were assessment pulmonary veins' ostialablation was performed at the segments showing earliestactivation of pulnonary vein potentials. The end pointwas designed: 1 ) elimination of pulmonary vein po-tential; 2) pulmonary vein potential dissociation fromatrial waves; 3) atrial ectopic beats disappear. ResultsA total of 36 pulmonary veins were ablated, in-cluding 16 left superior, 12 right superior, 7 left in-ferior and 1 right inferior. 1 pulmonary vein in 2 pa-tients was ablated, 2 pulmonary veins in 8 patientswere ablated, 3 pulmonary veins were ablated in 5patients and 4 pulmonary veins were ablated in 1 pa-tient. Procedure duration and fluoroscopy time respec-tively were 186.7 _+ 63.8 min and 51.5 + 15.0 min.During the follow-up 1- 12 months, 11 patients(68.7 % ) were free of AF without any antiarrhythmicdrugs, 2 of them were reablation, effective in 3/16(18.7%) and unsuccessful in 2/16 (12.6%) . 2cases recurred with atrial premature, 1 was treated withamiodarone and the other was repeat electrophysiologi-cal mapping and ablation, 5 cases with

  13. Interactive training system for interventional electrocardiology procedures.

    Talbot, Hugo; Spadoni, Federico; Duriez, Christian; Sermesant, Maxime; O'Neill, Mark; Jaïs, Pierre; Cotin, Stéphane; Delingette, Hervé

    2017-01-01

    Recent progress in cardiac catheterization and devices has allowed the development of new therapies for severe cardiac diseases like arrhythmias and heart failure. The skills required for such interventions are very challenging to learn, and are typically acquired over several years. Virtual reality simulators may reduce this burden by allowing trainees to practice such procedures without risk to patients. In this paper, we propose the first training system dedicated to cardiac electrophysiology, including pacing and ablation procedures. Our framework involves the simulation of a catheter navigation that reproduces issues intrinsic to intra-cardiac catheterization, and a graphics processing unit (GPU)-based electrophysiological model. A multithreading approach is proposed to compute both physical simulations (navigation and electrophysiology) asynchronously. With this method, we reach computational performances that account for user interactions in real-time. Based on a scenario of cardiac arrhythmia, we demonstrate the ability of the user-guided simulator to navigate inside vessels and cardiac cavities with a catheter and to reproduce an ablation procedure involving: extra-cellular potential measurements, endocardial surface reconstruction, electrophysiology mapping, radio-frequency (RF) ablation, as well as electrical stimulation. A clinical evaluation assessing the different aspects of the simulation is presented. This works is a step towards computerized medical learning curriculum.

  14. Dragging technique versus blanching technique for endometrial ablation with the Nd:YAG laser in the treatment of chronic menorrhagia.

    Lomano, J M

    1988-07-01

    Endometrial ablation performed with the Nd:YAG laser was developed to treat patients with chronic menorrhagia as an alternative to hysterectomy. The original dragging technique may result in an obscured operating field and fluid overload. This study compares results of endometrial ablation performed in 62 patients. The first 17 procedures were performed by use of the dragging technique; the last 45 procedures were performed with a blanching technique. Both procedures were performed at the same institution and by the same surgeon. Sixty-five percent of patients undergoing the blanching technique became amenorrheic after the procedure versus 12% of those undergoing the dragging technique. Moreover, the blanching technique required less time, fewer joules of energy, and resulted in less fluid absorption by the patient. The blanching technique is apparently more effective, easier to accomplish, and safer for the patient than the dragging technique.

  15. Interactive Volumetry Of Liver Ablation Zones

    Egger, Jan; Brandmaier, Philipp; Seider, Daniel; Gawlitza, Matthias; Strocka, Steffen; Voglreiter, Philip; Dokter, Mark; Hofmann, Michael; Kainz, Bernhard; Hann, Alexander; Chen, Xiaojun; Alhonnoro, Tuomas; Pollari, Mika; Schmalstieg, Dieter; Moche, Michael

    2015-01-01

    Percutaneous radiofrequency ablation (RFA) is a minimally invasive technique that destroys cancer cells by heat. The heat results from focusing energy in the radiofrequency spectrum through a needle. Amongst others, this can enable the treatment of patients who are not eligible for an open surgery. However, the possibility of recurrent liver cancer due to incomplete ablation of the tumor makes post-interventional monitoring via regular follow-up scans mandatory. These scans have to be carefully inspected for any conspicuousness. Within this study, the RF ablation zones from twelve post-interventional CT acquisitions have been segmented semi-automatically to support the visual inspection. An interactive, graph-based contouring approach, which prefers spherically shaped regions, has been applied. For the quantitative and qualitative analysis of the algorithm's results, manual slice-by-slice segmentations produced by clinical experts have been used as the gold standard (which have also been compared among each o...

  16. Ultrafast laser ablation of transparent materials

    Bauer, Lara; Russ, Simone; Kaiser, Myriam; Kumkar, Malte; Faißt, Birgit; Weber, Rudolf; Graf, Thomas

    2016-03-01

    The present work investigates the influence of the pulse duration and the temporal spacing between pulses on the ablation of aluminosilicate glass by comparing the results obtained with pulse durations of 0.4 ps and 6 ps. We found that surface modifications occur already at fluences below the single pulse ablation threshold and that laser-induced periodic surface structures (LIPSS) emerge as a result of those surface modifications. For 0.4 ps the ablation threshold fluences is lower than for 6 ps. Scanning electron micrographs of LIPSS generated with 0.4 ps exhibit a more periodic and less coarse structure as compared to structures generated with 6 ps. Furthermore we report on the influence of temporal spacing between the pulses on the occurrence of LIPSS and the impact on the quality of the cutting edge. Keywords: LIPSS,

  17. Kinetic depletion model for pellet ablation

    Kuteev, Boris V. [State Technical Univ., St. Petersburg (Russian Federation)

    2001-11-01

    A kinetic model for depletion effect, which determines pellet ablation when the pellet passes a rational magnetic surface, is formulated. The model predicts a moderate decrease of the ablation rate compared with the earlier considered monoenergy versions [1, 2]. For typical T-10 conditions the ablation rate reduces by a reactor of 2.5 when the 1-mm pellet penetrates through the plasma center. A substantial deceleration of pellets -about 15% per centimeter of low shire rational q region; is predicted. Penetration for Low Field Side and High Field Side injections is considered taking into account modification of the electron distribution function by toroidal magnetic field. It is shown that Shafranov shift and toroidal effects yield the penetration length for HFS injection higher by a factor of 1.5. This fact should be taken into account when plasma-shielding effects on penetration are considered. (author)

  18. Deep Dive Topic: Choosing between ablators

    Hurricane, O. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Thomas, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Olson, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-14

    Recent data on implosions using identical hohlraums and very similar laser drives underscores the conundrum of making a clear choice of one ablator over another. Table I shows a comparison of Be and CH in a nominal length, gold, 575 μm-diameter, 1.6 mg/cc He gas-fill hohlraum while Table II shows a comparison of undoped HDC and CH in a +700 length, gold, 575 μm diameter, 1.6 mg/cc He gas fill hohlraum. As can be seen in the tables, the net integrated fusion performance of these ablators is the same to within error bars. In the case of the undoped HDC and CH ablators, the hot spot shapes of the implosions were nearly indistinguishable for the experiments listed in Table II.

  19. Thermal Ablation Modeling for Silicate Materials

    Chen, Yih-Kanq

    2016-01-01

    A thermal ablation model for silicates is proposed. The model includes the mass losses through the balance between evaporation and condensation, and through the moving molten layer driven by surface shear force and pressure gradient. This model can be applied in ablation simulations of the meteoroid or glassy Thermal Protection Systems for spacecraft. Time-dependent axi-symmetric computations are performed by coupling the fluid dynamics code, Data-Parallel Line Relaxation program, with the material response code, Two-dimensional Implicit Thermal Ablation simulation program, to predict the mass lost rates and shape change. For model validation, the surface recession of fused amorphous quartz rod is computed, and the recession predictions reasonably agree with available data. The present parametric studies for two groups of meteoroid earth entry conditions indicate that the mass loss through moving molten layer is negligibly small for heat-flux conditions at around 1 MW/cm(exp. 2).

  20. Numerical Modeling of Ablation Heat Transfer

    Ewing, Mark E.; Laker, Travis S.; Walker, David T.

    2013-01-01

    A unique numerical method has been developed for solving one-dimensional ablation heat transfer problems. This paper provides a comprehensive description of the method, along with detailed derivations of the governing equations. This methodology supports solutions for traditional ablation modeling including such effects as heat transfer, material decomposition, pyrolysis gas permeation and heat exchange, and thermochemical surface erosion. The numerical scheme utilizes a control-volume approach with a variable grid to account for surface movement. This method directly supports implementation of nontraditional models such as material swelling and mechanical erosion, extending capabilities for modeling complex ablation phenomena. Verifications of the numerical implementation are provided using analytical solutions, code comparisons, and the method of manufactured solutions. These verifications are used to demonstrate solution accuracy and proper error convergence rates. A simple demonstration of a mechanical erosion (spallation) model is also provided to illustrate the unique capabilities of the method.

  1. Complete regeneration of ablated eyestalk in penaeid prawn, Penaeus monodon

    Desai, U.M.; Achuthankutty, C.T.

    Ablation of one eyestalk is generally practised in all commercial prawn hatcheries to induce gonad maturation and spawning. An observation was made that the ablated eyestalk of spent females of the tiger prawn Penaeus monodon was completely...

  2. Alcohol septal ablation in patients with hypertrophic obstructive cardiomyopathy

    Jensen, Morten K; Prinz, Christian; Horstkotte, Dieter;

    2013-01-01

    The infarction induced by alcohol septal ablation (ASA) may predispose to arrhythmia and sudden cardiac death (SCD).......The infarction induced by alcohol septal ablation (ASA) may predispose to arrhythmia and sudden cardiac death (SCD)....

  3. Radiofrequency ablation of a misdiagnosed Brodie’s abscess

    Chan, RS; Abdullah, BJJ; Aik, S; Tok, CH

    2011-01-01

    Radiofrequency ablation (RFA) therapy is recognised as a safe and effective treatment option for osteoid osteoma. This case report describes a 27-year-old man who underwent computed tomography (CT)-guided percutaneous RFA for a femoral osteoid osteoma, which was diagnosed based on his clinical presentation and CT findings. The patient developed worsening symptoms complicated by osteomyelitis after the procedure. His clinical progression and subsequent MRI findings had led to a revised diagnosis of a Brodie’s abscess, which was further supported by the eventual resolution of his symptoms following a combination of antibiotics treatment and surgical irrigations. This case report illustrates the unusual MRI features of osteomyelitis mimicking soft tissue tumours following RFA of a misdiagnosed Brodie’s abscess and highlights the importance of a confirmatory histopathological diagnosis for an osteoid osteoma prior to treatment. PMID:22291860

  4. Thermal ablation of liver metastases from colorectal cancer: radiofrequency, microwave and laser ablation therapies.

    Vogl, Thomas J; Farshid, Parviz; Naguib, Nagy N N; Darvishi, Abbas; Bazrafshan, Babak; Mbalisike, Emmanuel; Burkhard, Thorsten; Zangos, Stephan

    2014-07-01

    Surgery is currently considered the treatment of choice for patients with colorectal cancer liver metastases (CRLM) when resectable. The majority of these patients can also benefit from systemic chemotherapy. Recently, local or regional therapies such as thermal ablations have been used with acceptable outcomes. We searched the medical literature to identify studies and reviews relevant to radiofrequency (RF) ablation, microwave (MW) ablation and laser-induced thermotherapy (LITT) in terms of local progression, survival indexes and major complications in patients with CRLM. Reviewed literature showed a local progression rate between 2.8 and 29.7 % of RF-ablated liver lesions at 12-49 months follow-up, 2.7-12.5 % of MW ablated lesions at 5-19 months follow-up and 5.2 % of lesions treated with LITT at 6-month follow-up. Major complications were observed in 4-33 % of patients treated with RF ablation, 0-19 % of patients treated with MW ablation and 0.1-3.5 % of lesions treated with LITT. Although not significantly different, the mean of 1-, 3- and 5-year survival rates for RF-, MW- and laser ablated lesions was (92.6, 44.7, 31.1 %), (79, 38.6, 21 %) and (94.2, 61.5, 29.2 %), respectively. The median survival in these methods was 33.2, 29.5 and 33.7 months, respectively. Thermal ablation may be an appropriate alternative in patients with CRLM who have inoperable liver lesions or have operable lesions as an adjunct to resection. However, further competitive evaluation should clarify the efficacy and priority of these therapies in patients with colorectal cancer liver metastases.

  5. Ablative Rocket Deflector Testing and Computational Modeling

    Allgood, Daniel C.; Lott, Jeffrey W.; Raines, Nickey

    2010-01-01

    A deflector risk mitigation program was recently conducted at the NASA Stennis Space Center. The primary objective was to develop a database that characterizes the behavior of industry-grade refractory materials subjected to rocket plume impingement conditions commonly experienced on static test stands. The program consisted of short and long duration engine tests where the supersonic exhaust flow from the engine impinged on an ablative panel. Quasi time-dependent erosion depths and patterns generated by the plume impingement were recorded for a variety of different ablative materials. The erosion behavior was found to be highly dependent on the material s composition and corresponding thermal properties. For example, in the case of the HP CAST 93Z ablative material, the erosion rate actually decreased under continued thermal heating conditions due to the formation of a low thermal conductivity "crystallization" layer. The "crystallization" layer produced near the surface of the material provided an effective insulation from the hot rocket exhaust plume. To gain further insight into the complex interaction of the plume with the ablative deflector, computational fluid dynamic modeling was performed in parallel to the ablative panel testing. The results from the current study demonstrated that locally high heating occurred due to shock reflections. These localized regions of shock-induced heat flux resulted in non-uniform erosion of the ablative panels. In turn, it was observed that the non-uniform erosion exacerbated the localized shock heating causing eventual plume separation and reversed flow for long duration tests under certain conditions. Overall, the flow simulations compared very well with the available experimental data obtained during this project.

  6. Stereotactic Body Radiotherapy and Ablative Therapies for Lung Cancer.

    Abbas, Ghulam; Danish, Adnan; Krasna, Mark J

    2016-07-01

    The treatment paradigm for early stage lung cancer and oligometastatic disease to the lung is rapidly changing. Ablative therapies, especially stereotactic body radiation therapy, are challenging the surgical gold standard and have the potential to be the standard for operable patients with early stage lung cancer who are high risk due to co- morbidities. The most commonly used ablative modalities include stereotactic body radiation therapy, microwave ablation, and radiofrequency ablation.

  7. Subcellular analysis by laser ablation electrospray ionization mass spectrometry

    Vertes, Akos; Stolee, Jessica A; Shrestha, Bindesh

    2014-12-02

    In various embodiments, a method of laser ablation electrospray ionization mass spectrometry (LAESI-MS) may generally comprise micro-dissecting a cell comprising at least one of a cell wall and a cell membrane to expose at least one subcellular component therein, ablating the at least one subcellular component by an infrared laser pulse to form an ablation plume, intercepting the ablation plume by an electrospray plume to form ions, and detecting the ions by mass spectrometry.

  8. Ablation of carbide materials with femtosecond pulses

    Dumitru, Gabriel; Romano, Valerio; Weber, Heinz P.; Sentis, Marc; Marine, Wladimir

    2003-01-01

    The response of cemented tungsten carbide and of titanium carbonitride was investigated with respect to damage and ablation properties, under interaction with ultrashort laser pulses. These carbide materials present high microhardness and are of significant interest for tribological applications. The experiments were carried out in air with a commercial Ti:sapphire laser at energy densities on the target up to 6.5 J/cm 2. The irradiated target surfaces were analyzed with optical, SEM and AFM techniques and the damage and ablation threshold values were determined using the measured spot diameters and the calculated incident energy density distributions.

  9. Testing of Advanced Conformal Ablative TPS

    Gasch, Matthew; Agrawal, Parul; Beck, Robin

    2013-01-01

    In support of the CA250 project, this paper details the results of a test campaign that was conducted at the Ames Arcjet Facility, wherein several novel low density thermal protection (TPS) materials were evaluated in an entry like environment. The motivation for these tests was to investigate whether novel conformal ablative TPS materials can perform under high heat flux and shear environment as a viable alternative to rigid ablators like PICA or Avcoat for missions like MSL and beyond. A conformable TPS over a rigid aeroshell has the potential to solve a number of challenges faced by traditional rigid TPS materials (such as tiled Phenolic Impregnated Carbon Ablator (PICA) system on MSL, and honeycomb-based Avcoat on the Orion Multi Purpose Crew Vehicle (MPCV)). The compliant (high strain to failure) nature of the conformable ablative materials will allow better integration of the TPS with the underlying aeroshell structure and enable monolithic-like configuration and larger segments to be used in fabrication.A novel SPRITE1 architecture, developed by the researchers at NASA Ames was used for arcjet testing. This small probe like configuration with 450 spherecone, enabled us to test the materials in a combination of high heat flux, pressure and shear environment. The heat flux near the nose were in the range of 500-1000 W/sq cm whereas in the flank section of the test article the magnitudes were about 50 of the nose, 250-500W/sq cm range. There were two candidate conformable materials under consideration for this test series. Both test materials are low density (0.28 g/cu cm) similar to Phenolic Impregnated Carbon Ablator (PICA) or Silicone Impregnated Refractory Ceramic Ablator (SIRCA) and are comprised of: A flexible carbon substrate (Carbon felt) infiltrated with an ablative resin system: phenolic (Conformal-PICA) or silicone (Conformal-SICA). The test demonstrated a successful performance of both the conformable ablators for heat flux conditions between 50

  10. Dose reduction of scattered photons from concrete walls lined with lead: Implications for improvement in design of megavoltage radiation therapy facility mazes

    Al-Affan, I. A. M., E-mail: info@medphys-environment.co.uk; Hugtenburg, R. P.; Piliero, M. [Swansea University, Swansea SA2 8PP (United Kingdom); Bari, D. S. [Swansea University, Swansea SA2 8PP, United Kingdom and University of Zakho, Duhok (Iraq); Al-Saleh, W. M. [Swansea University, Swansea SA2 8PP, United Kingdom and King Saud Bin Abdulaziz University for Health Science, Hofuf (Saudi Arabia); Evans, S. [Department of Medical Physics and Clinical Engineering, Singleton Hospital, Swansea SA2 8QA (United Kingdom); Al-Hasan, M.; Al-Zughul, B. [College of Sciences, Zarqa University, Zarqa (Jordan); Al-Kharouf, S. [The Royal Scientific Society, Amman (Jordan); Ghaith, A. [Association of Arab Universities, Amman (Jordan)

    2015-02-15

    Purpose: This study explores the possibility of using lead to cover part of the radiation therapy facility maze walls in order to absorb low energy photons and reduce the total dose at the maze entrance of radiation therapy rooms. Methods: Experiments and Monte Carlo simulations were utilized to establish the possibility of using high-Z materials to cover the concrete walls of the maze in order to reduce the dose of the scattered photons at the maze entrance. The dose of the backscattered photons from a concrete wall was measured for various scattering angles. The dose was also calculated by the FLUKA and EGSnrc Monte Carlo codes. The FLUKA code was also used to simulate an existing radiotherapy room to study the effect of multiple scattering when adding lead to cover the concrete walls of the maze. Monoenergetic photons were used to represent the main components of the x ray spectrum up to 10 MV. Results: It was observed that when the concrete wall was covered with just 2 mm of lead, the measured dose rate at all backscattering angles was reduced by 20% for photons of energy comparable to Co-60 emissions and 70% for Cs-137 emissions. The simulations with FLUKA and EGS showed that the reduction in the dose was potentially even higher when lead was added. One explanation for the reduction is the increased absorption of backscattered photons due to the photoelectric interaction in lead. The results also showed that adding 2 mm lead to the concrete walls and floor of the maze reduced the dose at the maze entrance by up to 90%. Conclusions: This novel proposal of covering part or the entire maze walls with a few millimeters of lead would have a direct implication for the design of radiation therapy facilities and would assist in upgrading the design of some mazes, especially those in facilities with limited space where the maze length cannot be extended to sufficiently reduce the dose.

  11. Efficacy and satisfaction rate comparing endometrial ablation by rollerball electrocoagulation to uterine balloon thermal ablation in a randomised controlled trial.

    Zon-Rabelink, I.A.A. van; Vleugels, M.P.; Merkus, J.M.W.M.; Graaf, R.M. de

    2004-01-01

    OBJECTIVE: To compare two methods of endometrial ablation, hysteroscopic rollerball electrocoagulation (RBE) and non-hysteroscopic uterine balloon thermal ablation (Thermachoice trade mark ), regarding efficacy for reducing dysfunctional uterine bleeding and patients satisfaction rate. METHODS: A ra

  12. Experimental measurement of ablation effects in plasma armature railguns

    Parker, J.V.; Parsons, W.M.

    1986-01-01

    Experimental evidence supporting the importance of ablation in plasma armature railguns is presented. Experiments conducted using the HYVAX and MIDI-2 railguns are described. Several indirect effects of ablation are identified from the experimental results. An improved ablation model of plasma armature dynamics is proposed which incorporates the restrike process.

  13. Cardiac ablation by transesophageal high intensity focused ultrasound

    JIANG Chen-xi; YU Rong-hui; MA Chang-sheng

    2010-01-01

    @@ Cardiac ablation is an important modality of invasive therapy in modern cardiology, especially in the treatment of arrhythmias, as well as other diseases such as hypertrophic obstructive cardiomyopathy (HOCM). Since Huang et al1 used radiofrequency (RF) to ablate canine atrial ventricular junction, RF has developed into the leading energy source in catheter ablation of arrhythmias.

  14. Effects of repeated use and resterilization on structural and functional integrity of microwave ablation antennas.

    Finck, Cyrielle A; Zur Linden, Alex R; Singh, Ameet; Foster, Robert A; Nykamp, Stephanie G; Sears, William C

    2017-04-01

    OBJECTIVE To determine effects of repeated use and resterilization on structural and functional integrity of microwave ablation (MWA) antennas. SAMPLE 17 cooled-shaft MWA antennas (3 groups of 5 antennas/group and 2 control antennas). PROCEDURES 1, 2, and 3 ablations in the livers of bovine cadavers were performed at the maximum recommended settings. Antennas were cleaned and sterilized in hydrogen peroxide plasma, and the process was repeated (reprocessing cycle; n = 6). Control antennas were only sterilized (6 times). Aerobic and anaerobic bacterial cultures were performed, and antennas were microscopically assessed for damage. RESULTS 6 cycles were completed. Thirteen of 15 MWA antennas remained functional for up to 4 cycles, 10 were functional after 5 cycles, and only 7 were functional after 6 cycles. Progressive tearing of the silicone coating of the antennas was observed, with a negative effect of the number of cycles for silicone tearing. Size of the ablation zone decreased mildly over time after cycles 5 and 6; however, this was not considered clinically relevant. No significant changes in the shape of ablation zones were detected. All cultures yielded negative results, except for an isolated case, which was considered a contaminant. CONCLUSIONS AND CLINICAL RELEVANCE Structural and functional integrity of the microwave antennas remained acceptable during repeated use and reprocessing for up to 4 cycles. However, there was a decrease in functional integrity at cycles 5 and 6. We suggest that these microwave antennas be subjected to > 3 reprocessing cycles. Antennas should be carefully examined before reuse.

  15. Atrio-esophageal fistula after AF ablation: Pathophysiology,Prevention & Treatment

    Carlo Pappone; Gabriele Vicedomini; Vincenzo Santinelli

    2013-10-01

    Full Text Available Atrioesophageal fistula is a very rare but often fatal late complication of atrial fibrillation ablation procedures resulting from thermal injury to the esophagus and surrounding structures. Causes of death include cerebral air embolism, massive gastrointestinal bleeding, and septic shock. Because of its unusual rate of occurrence, there has not been an uniform approach to either the diagnosis or corrective therapy. This low incidence poses a challenge in strictly determining effective preventive measures during and immediately following posterior wall left atrial ablation. Currently, strategies proposed to prevent esophageal injury include reduced power titration while ablating the posterior left atrial wall, limiting RF delivery time, avoiding overlapping ablation lines as well as monitoring intraluminal esophageal temperature, using conscious sedation rather than general anesthesia for better pain perception, monitoring intraprocedural esophageal position in relation to the posterior left atrium and extensive patient education regarding signs and symptoms of esophageal injury. Early diagnosis is essential to enable therapeutic preventive strategies to minimize the excessive morbidity and mortality associated with this condition. Unfortunately, despite application of such preventive measures, cases of atrial-esophageal fistula have still been reported. If esophageal injury with fistula formation is clinically suspected, a prompt diagnosis and an immediate aggressive intervention including stenting and/or surgical intervention is required for the patient’survival.

  16. Percutaneous Intraductal Radiofrequency Ablation is a Safe Treatment for Malignant Biliary Obstruction: Feasibility and Early Results

    Mizandari, Malkhaz [Tbilisi State Medical University, Department of Radiology (Georgia); Pai, Madhava, E-mail: madhava.pai@imperial.ac.uk; Xi Feng [Imperial College, London, Hammersmith Hospital Campus, Department of Surgery (United Kingdom); Valek, Vlastimil; Tomas, Andrasina [University Hospital Brno Bohunice, Department of Radiology (Czech Republic); Quaretti, Pietro [IRCCS Policlinico San Matteo, Department of Radiology (Italy); Golfieri, Rita; Mosconi, Cristina [University of Bologna, Department of Radiology, Policlinico S. Orsola-Malpighi (Italy); Ao Guokun [The 309 Hospital of Chinese PLA, Department of Radiology (China); Kyriakides, Charis [Imperial College, London, Hammersmith Hospital Campus, Department of Surgery (United Kingdom); Dickinson, Robert [Imperial College London, Department of Bioengineering (United Kingdom); Nicholls, Joanna; Habib, Nagy, E-mail: nagy.habib@imperial.ac.uk [Imperial College, London, Hammersmith Hospital Campus, Department of Surgery (United Kingdom)

    2013-06-15

    Purpose. Previous clinical studies have shown the safety and efficacy of this novel radiofrequency ablation catheter when used for endoscopic palliative procedures. We report a retrospective study with the results of first in man percutaneous intraductal radiofrequency ablation in patients with malignant biliary obstruction. Methods. Thirty-nine patients with inoperable malignant biliary obstruction were included. These patients underwent intraductal biliary radiofrequency ablation of their malignant biliary strictures following external biliary decompression with an internal-external biliary drainage. Following ablation, they had a metal stent inserted. Results. Following this intervention, there were no 30-day mortality, hemorrhage, bile duct perforation, bile leak, or pancreatitis. Of the 39 patients, 28 are alive and 10 patients are dead with a median survival of 89.5 (range 14-260) days and median stent patency of 84.5 (range 14-260) days. One patient was lost to follow-up. All but one patient had their stent patent at the time of last follow-up or death. One patient with stent blockage at 42 days postprocedure underwent percutaneous transhepatic drain insertion and restenting. Among the patients who are alive (n = 28) the median stent patency was 92 (range 14-260) days, whereas the patients who died (n = 10) had a median stent patency of 62.5 (range 38-210) days. Conclusions. In this group of patients, it appears that this new approach is feasible and safe. Efficacy remains to be proven in future, randomized, prospective studies.

  17. Advances and historical developments of MW hyperthermia and the relevance to thermal ablation

    Turner, Paul F.; Youd, Thomas; Turner, P. Scott

    2007-02-01

    Early work utilizing MW energy for thermal treatment or ablation of tissues such as liver using coherent phased arrays began in 1979. This early work involved the use of multiple interstitial antennas driven with the same phase and equal power at 915 MHz through the use of a power splitter. Early models of the antenna utilized a hypodermic needle that was transformed into an antenna by the deployment of an insulated coaxial central wire beyond the end of the needle. Early unpublished treatments of tissue phantoms and swine liver demonstrated the feasibility of such a design for selective tissue damage, but sufficient image and targeting methods had not been sufficiently developed to support such applications. MW therapeutic technology was subsequently commercialized in combination with invasive radiation therapy called brachytherapy. For this application coherent arrays of coaxial antennas were inserted into cancerous tumors. Initial investigators would deploy these into the tumor through 14 gauge plastic angiocatheters. In later procedures, the antennas were inserted into the same closed-end plastic catheters used for insertion of the radiation sources. MW energy delivery through the walls of closed-end plastic catheters and numerical pretreatment planning has been in clinical practice since 1984. Recent development of numerical models, split tissue equivalent phantoms with IR imaging, and tissue ablation studies have led to new insights in microwave ablation applications. Current research will improve ablative heat therapy with increased temperatures and power to improve stand alone thermal treatments.

  18. Mathematical modeling of epicardial RF ablation of atrial tissue with overlying epicardial fat.

    Suárez, Ana González; Hornero, Fernando; Berjano, Enrique J

    2010-02-04

    The efficacy of treating atrial fibrillation by RF ablation on the epicardial surface is currently under question due to the presence of epicardial adipose tissue interposed between the ablation electrode and target site (atrial wall). The problem is probably caused by the electrical conductivity of the fat (0.02 S/m) being lower than that of the atrial tissue (0.4-0.6 S/m). Since our objective is to improve epicardial RF ablation techniques, we planned a study based on a two-dimensional mathematical model including an active electrode, a fragment of epicardial fat over a fragment of atrial tissue, and a section of atrium with circulating blood. Different procedures for applying RF power were studied, such as varying the frequency, using a cooled instead of a dry electrode, and different modes of controlling RF power (constant current, temperature and voltage) for different values of epicardial fat thickness. In general, the results showed that the epicardial fat layer seriously impedes the passage of RF current, thus reducing the effectiveness of atrial wall RF ablation.

  19. Anaesthesia for foetoscopic Laser ablation- a retrospective study

    Vaishali Kumbhar

    2016-01-01

    Full Text Available Background and Aims: Twin pregnancy with monochorionic placenta may be associated with arteriovenous vascular anastomosis of the placental vessels resulting in twin-to-twin transfusion syndrome (TTTS and twin reversed arterial perfusion syndrome (TRAP. Foetoscopic LASER ablation (FLA is the treatment of choice in reducing foetal mortality related to this. Methods: A retrospective review of medical records of 41 FLA procedures for TTTS and TRAP were analysed for anaesthetic management. Thirty-four patients received subarachnoid block, three combined spinal-epidural block, three general anaesthesia and one local anaesthesia with sedation. Nitroglycerine 5 mg patch was used for tocolysis 1 h before the procedure and continued for 24-48 h postoperatively. Results: Bupivacaine was used in 34 patients, and ropivacaine in three patients. Mean dose of bupivacaine 0.5% was 2.43 ± 0.32 ml and ropivacaine 0.75% was 2.85 ± 0.19 ml. The mean duration of surgery was 117.07 ± 28 min. Mild hypotension occurred in all patients under spinal anaesthesia and was treated with vasopressors. The foetal outcome among all 41 patients were 13 delivered live twins, 15 had a single live baby with intrauterine death of other twin baby. In 12 patients, both babies were intrauterine death. One patient was lost for follow-up. Conclusion: Foetoscopic procedures can be done under central neuraxial block, however occasionally general anaesthesia may be required.

  20. Anaesthesia for foetoscopic Laser ablation- a retrospective study

    Kumbhar, Vaishali; Radhika, M; Gundappa, Parameswara; Simha, Jayashree; Radhakrishnan, Prathima

    2016-01-01

    Background and Aims: Twin pregnancy with monochorionic placenta may be associated with arteriovenous vascular anastomosis of the placental vessels resulting in twin-to-twin transfusion syndrome (TTTS) and twin reversed arterial perfusion syndrome (TRAP). Foetoscopic LASER ablation (FLA) is the treatment of choice in reducing foetal mortality related to this. Methods: A retrospective review of medical records of 41 FLA procedures for TTTS and TRAP were analysed for anaesthetic management. Thirty-four patients received subarachnoid block, three combined spinal-epidural block, three general anaesthesia and one local anaesthesia with sedation. Nitroglycerine 5 mg patch was used for tocolysis 1 h before the procedure and continued for 24–48 h postoperatively. Results: Bupivacaine was used in 34 patients, and ropivacaine in three patients. Mean dose of bupivacaine 0.5% was 2.43 ± 0.32 ml and ropivacaine 0.75% was 2.85 ± 0.19 ml. The mean duration of surgery was 117.07 ± 28 min. Mild hypotension occurred in all patients under spinal anaesthesia and was treated with vasopressors. The foetal outcome among all 41 patients were 13 delivered live twins, 15 had a single live baby with intrauterine death of other twin baby. In 12 patients, both babies were intrauterine death. One patient was lost for follow-up. Conclusion: Foetoscopic procedures can be done under central neuraxial block, however occasionally general anaesthesia may be required. PMID:28003695

  1. Percutaneous treatment of bone tumors by radiofrequency thermal ablation

    Ruiz Santiago, Fernando, E-mail: ferusan@ono.com [Department of Radiology, Hospital of Traumatology (Ciudad Sanitaria Virgen de las Nieves), Carretera de Jaen SN, 18013 Granada (Spain); Mar Castellano Garcia, Maria del; Guzman Alvarez, Luis [Department of Radiology, Hospital of Traumatology (Ciudad Sanitaria Virgen de las Nieves), Carretera de Jaen SN, 18013 Granada (Spain); Martinez Montes, Jose Luis [Department of Traumatology, Hospital of Traumatology (Ciudad Sanitaria Virgen de las Nieves), Carretera de Jaen SN, 18013 Granada (Spain); Ruiz Garcia, Manuel; Tristan Fernandez, Juan MIguel [Department of Radiology, Hospital of Traumatology (Ciudad Sanitaria Virgen de las Nieves), Carretera de Jaen SN, 18013 Granada (Spain)

    2011-01-15

    We present our experience of the treatment of bone tumors with radiofrequency thermal ablation (RFTA). Over the past 4 years, we have treated 26 cases (22 benign and 4 malignant) using CT-guided RFTA. RFTA was the sole treatment in 19 cases and was combined with percutaneous cementation during the same session in the remaining seven cases. Our approach to the tumors was simplified, using a single point of entrance for both RFTA and percutaneous osteoplasty. In the benign cases, clinical success was defined as resolution of pain within 1 month of the procedure and no recurrence during the follow-up period. It was achieved in 19 out of the 21 patients in which curative treatment was attempted. The two non-resolved cases were a patient with osteoid osteoma who developed a symptomatic bone infarct after a symptom-free period of 2 months and another with femoral diaphysis osteoblastoma who suffered a pathological fracture after 8 months without symptoms. The procedure was considered clinically successful in the five cases (4 malign and 1 benign) in which palliative treatment was attempted, because there was a mean ({+-}SD) reduction in visual analogue scale (VAS) pain score from 9.0 {+-} 0.4 before the procedure to <4 during the follow-up period.

  2. The neutron dose equivalent evaluation and shielding at the maze entrance of a Varian Clinac 23EX treatment room

    Wang Xudong; Esquivel, Carlos; Nes, Elena; Shi Chengyu; Papanikolaou, Nikos; Charlton, Michael [University of Texas Health Science Center, San Antonio, Texas 78229 (United States); South Texas Accelerated Research Therapeutics (START) Center for Cancer Care, San Antonio, Texas 78229 (United States); University of Texas Health Science Center, San Antonio, Texas 78229 (United States)

    2011-03-15

    Purpose: To evaluate the neutron and photon dose equivalent rate (H{sub n,D} and H{sub G}) at the outer maze entrance and the adjacent treatment console area after the installation of a Varian Clinac 23EX accelerator with a higher beam energy than its predecessor. The evaluation was based on measurements and comparison with several empirical calculations. The effectiveness of borated polyethylene (BPE) boards, as a maze wall lining material, on neutron dose and photon dose reduction is also reported. Methods: A single energy Varian 6 MV photon linear accelerator (linac) was replaced with a Varian Clinac 23EX accelerator capable of producing 18 MV photons in a vault originally designed for the former accelerator. In order to evaluate and redesign the shielding of the vault, the neutron dose equivalent H{sub n,D} was measured using an Andersson-Braun neutron Rem meter and the photon dose equivalent H{sub G} was measured using a Geiger Mueller and an ion chamber {gamma}-ray survey meter at the outer maze entrance. The measurement data were compared to semiempirical calculations such as the Kersey method, the modified Kersey method, and a newly proposed method by Falcao et al. Additional measurements were taken after BPE boards were installed on the maze walls as a neutron absorption lining material. Results: With the gantry head tilted close to the inner maze entrance and with the jaws closed, both neutron dose equivalent and photon dose equivalent reached their maximum. Compared to the measurement results, the Kersey method overestimates the neutron dose equivalent H{sub n,D} by about two to four times (calculation/measurement ratio{approx_equal}2.4-3.8). Falcao's method largely overestimates the H{sub n,D} (calculation/measurement ratio{approx_equal}3.9-5.5). The modified Kersey method has a calculation to measurement ratio about 0.6-0.9. The photon dose equivalent calculation including McGinley's capture gamma dose equivalent equation estimates about 77

  3. Tumor lysis syndrome following endoscopic radiofrequency interstitial thermal ablation of colorectal liver metastases.

    Barry, B D

    2012-02-03

    Radiofrequency interstitial thermal ablation (RITA) provides a palliative option for patients suffering from metastatic liver disease. This procedure can be performed using a laparoscopic approach with laparoscopic ultrasound used to position the RITA probe. We describe a case of laparoscopic RITA performed for colorectal liver metastasis that was complicated by tumor lysis syndrome (TLS) following treatment. We consider RITA to be a safe procedure, as supported by the literature, but where intracorporal tumor lysis is the treatment goal we believe that the systemic release of tumor products can overwhelm the excretory capacity; therefore, TLS is an inevitable consequence in some patients.

  4. An event-driven distributed processing architecture for image-guided cardiac ablation therapy.

    Rettmann, M E; Holmes, D R; Cameron, B M; Robb, R A

    2009-08-01

    Medical imaging data is becoming increasing valuable in interventional medicine, not only for preoperative planning, but also for real-time guidance during clinical procedures. Three key components necessary for image-guided intervention are real-time tracking of the surgical instrument, aligning the real-world patient space with image-space, and creating a meaningful display that integrates the tracked instrument and patient data. Issues to consider when developing image-guided intervention systems include the communication scheme, the ability to distribute CPU intensive tasks, and flexibility to allow for new technologies. In this work, we have designed a communication architecture for use in image-guided catheter ablation therapy. Communication between the system components is through a database which contains an event queue and auxiliary data tables. The communication scheme is unique in that each system component is responsible for querying and responding to relevant events from the centralized database queue. An advantage of the architecture is the flexibility to add new system components without affecting existing software code. In addition, the architecture is intrinsically distributed, in that components can run on different CPU boxes, and even different operating systems. We refer to this Framework for Image-Guided Navigation using a Distributed Event-Driven Database in Real-Time as the FINDER architecture. This architecture has been implemented for the specific application of image-guided cardiac ablation therapy. We describe our prototype image-guidance system and demonstrate its functionality by emulating a cardiac ablation procedure with a patient-specific phantom. The proposed architecture, designed to be modular, flexible, and intuitive, is a key step towards our goal of developing a complete system for visualization and targeting in image-guided cardiac ablation procedures.

  5. Diagnostics of laser ablated plasma plumes

    Amoruso, S.; Toftmann, B.; Schou, Jørgen;

    2004-01-01

    The effect of an ambient gas on the expansion dynamics of laser ablated plasmas has been studied for two systems by exploiting different diagnostic techniques. First, the dynamics of a MgB2 laser produced plasma plume in an Ar atmosphere has been investigated by space-and time-resolved optical...

  6. Modeling sublimation of a charring ablator

    Balhoff, J. F.; Pike, R. W.

    1973-01-01

    The Hertz-Knudsen analysis is shown to accurately predict the sublimation rate from a charring ablator. Porosity is shown to have a significant effect on the surface temperature. The predominant carbon species found in the vapor is C3, which agrees well with the results of previous investigations.

  7. Combining Electrolysis and Electroporation for Tissue Ablation.

    Phillips, Mary; Rubinsky, Liel; Meir, Arie; Raju, Narayan; Rubinsky, Boris

    2015-08-01

    Electrolytic ablation is a method that operates by delivering low magnitude direct current to the target region over long periods of time, generating electrolytic products that destroy cells. This study was designed to explore the hypothesis stating that electrolytic ablation can be made more effective when the electrolysis-producing electric charges are delivered using electric pulses with field strength typical in reversible electroporation protocols. (For brevity we will refer to tissue ablation protocols that combine electroporation and electrolysis as E(2).) The mechanistic explanation of this hypothesis is related to the idea that products of electrolysis generated by E(2) protocols can gain access to the interior of the cell through the electroporation permeabilized cell membrane and therefore cause more effective cell death than from the exterior of an intact cell. The goal of this study is to provide a first-order examination of this hypothesis by comparing the charge dosage required to cause a comparable level of damage to a rat liver, in vivo, when using either conventional electrolysis or E(2) approaches. Our results show that E(2) protocols produce tissue damage that is consistent with electrolytic ablation. Furthermore, E(2) protocols cause damage comparable to that produced by conventional electrolytic protocols while delivering orders of magnitude less charge to the target tissue over much shorter periods of time.

  8. Bending diamonds by femtosecond laser ablation

    Balling, Peter; Esberg, Jakob; Kirsebom, Kim;

    2009-01-01

    We present a new method based on femtosecond laser ablation for the fabrication of statically bent diamond crystals. Using this method, curvature radii of 1 m can easily be achieved, and the curvature obtained is very uniform. Since diamond is extremely tolerant to high radiation doses, partly due...

  9. The Atrial Fibrillation Ablation Pilot Study

    Arbelo, Elena; Brugada, Josep; Hindricks, Gerhard;

    2014-01-01

    was achieved in 40.7% of patients (43.7% in paroxysmal AF; 30.2% in persistent AF; 36.7% in long-lasting persistent AF). A second ablation was required in 18% of the cases and 43.4% were under antiarrhythmic treatment. Thirty-three patients (2.5%) suffered an adverse event, 272 (21%) experienced a left atrial...

  10. Barium Ferrite Films Grown by Laser Ablation

    Lisfi, A.; Lodder, J.C.; Haan, de P.; Smithers, M.A.; Roesthuis, F.J.G.

    1998-01-01

    Pulsed laser ablation (PLA) has been used to grow barium ferrite films on Al2O3 single crystal substrates. When deposition occurs in an oxidising atmosphere at high temperatures, the films are single BaFe12O19 phase, very well oriented with (001) texture, and exhibit a large perpendicular magnetic a

  11. Safety of atrial fibrillation ablation with novel multi-electrode array catheters on uninterrupted anticoagulation-a single-center experience.

    Hayes, Christopher Ruslan

    2012-02-01

    INTRODUCTION: A recent single-center report indicated that the performance of atrial fibrillation ablation in patients on uninterrupted warfarin using a conventional deflectable tip electrode ablation catheter may be as safe as periprocedural discontinuation of warfarin and bridging with heparin. Novel multi-electrode array catheters for atrial fibrillation ablation are currently undergoing clinical evaluation. While offering the possibility of more rapid atrial fibrillation ablation, they are stiffer and necessitate the deployment of larger deflectable transseptal sheaths, and it remains to be determined if they increase the risk of cardiac perforation and vascular injury. Such potential risks would have implications for a strategy of uninterrupted periprocedural anticoagulation. METHOD AND RESULTS: We audited the safety outcomes of our atrial fibrillation ablation procedures using multi-electrode array ablation catheters in patients on uninterrupted warfarin (CHADS2 score>or=2) and in patients not on warfarin (uninterrupted aspirin). Two bleeding complications occurred in 49 patients on uninterrupted warfarin, both of which were managed successfully without longterm sequelae, and no bleeding complication occurred in 32 patients not on warfarin (uninterrupted aspirin). There were no thromboembolic events or other complication with either anticoagulant regimen. CONCLUSION: Despite the larger diameter and increased stiffness of multi-electrode array catheters and their deflectable transseptal sheaths, their use for catheter ablation in patients with atrial fibrillation on uninterrupted warfarin in this single-center experience does not appear to be unsafe, and thus, an adequately powered multicenter prospective randomized controlled trial should be considered.

  12. Acute and long term outcomes of catheter ablation using remote magnetic navigation for the treatment of electrical storm in patients with severe ischemic heart failure

    Jin, Qi; Jacobsen, Peter Karl; Pehrson, Steen;

    2015-01-01

    BACKGROUND: Catheter ablation with remote magnetic navigation (RMN) can offer some advantages compared to manual techniques. However, the relevant clinical evidence for how RMN-guided ablation affects electrical storm (ES) due to ventricular tachycardia (VT) in patients with severe ischemic heart......-guided catheter ablation can prevent VT recurrence and significantly reduce ICD shocks, suggesting that this strategy can be used as an alternative therapy for VT storm in SIHF patients with ICDs.......BACKGROUND: Catheter ablation with remote magnetic navigation (RMN) can offer some advantages compared to manual techniques. However, the relevant clinical evidence for how RMN-guided ablation affects electrical storm (ES) due to ventricular tachycardia (VT) in patients with severe ischemic heart...... was defined as noninducibility of any sustained monophasic VT at the end of the procedure. Long-term analysis addressed VT recurrence, ICD therapies and all-cause death. ES was acutely suppressed by ablation in all patients. RESULTS: Acute ablation success was obtained in 32 of 40 (80%) patients...

  13. A chemical model of meteoric ablation

    T. Vondrak

    2008-07-01

    Full Text Available Most of the extraterrestrial dust entering the Earth's atmosphere ablates to produce metal vapours, which have significant effects on the aeronomy of the upper mesosphere and lower thermosphere. A new Chemical Ablation Model (CAMOD is described which treats the physics and chemistry of ablation, by including the following processes: sputtering by inelastic collisions with air molecules before the meteoroid melts; evaporation of atoms and oxides from the molten particle; diffusion-controlled migration of the volatile constituents (Na and K through the molten particle; and impact ionization of the ablated fragments by hyperthermal collisions with air molecules. Evaporation is based on thermodynamic equilibrium in the molten meteoroid (treated as a melt of metal oxides, and between the particle and surrounding vapour phase. The loss rate of each element is then determined assuming Langmuir evaporation. CAMOD successfully predicts the meteor head echo appearance heights, observed from incoherent scatter radars, over a wide range of meteoroid velocities. The model also confirms that differential ablation explains common-volume lidar observations of K, Ca and Ca+ in fresh meteor trails. CAMOD is then used to calculate the injection rates into the atmosphere of a variety of elements as a function of altitude, integrated over the meteoroid mass and velocity distributions. The most abundant elements (Fe, Mg and Si have peak injection rates around 85 km, with Na and K about 8 km higher. The more refractory element Ca ablates around 82 km with a Na:Ca ratio of 4:1, which does therefore not explain the depletion of atomic Ca to Na, by more than 2 orders of magnitude, in the upper mesosphere. Diffusion of the most volatile elements (Na and K does not appear to be rate-limiting except in the fastest meteoroids. Non-thermal sputtering causes ~35% mass loss from the fastest (~60–70 km s−1 and smallest (10−17–10

  14. A chemical model of meteoric ablation

    T. Vondrak

    2008-12-01

    Full Text Available Most of the extraterrestrial dust entering the Earth's atmosphere ablates to produce metal vapours, which have significant effects on the aeronomy of the upper mesosphere and lower thermosphere. A new Chemical Ablation Model (CAMOD is described which treats the physics and chemistry of ablation, by including the following processes: sputtering by inelastic collisions with air molecules before the meteoroid melts; evaporation of atoms and oxides from the molten particle; diffusion-controlled migration of the volatile constituents (Na and K through the molten particle; and impact ionization of the ablated fragments by hyperthermal collisions with air molecules. Evaporation is based on thermodynamic equilibrium in the molten meteoroid (treated as a melt of metal oxides, and between the particle and surrounding vapour phase. The loss rate of each element is then determined assuming Langmuir evaporation. CAMOD successfully predicts the meteor head echo appearance heights, observed from incoherent scatter radars, over a wide range of meteoroid velocities. The model also confirms that differential ablation explains common-volume lidar observations of K, Ca and Ca+ in fresh meteor trails. CAMOD is then used to calculate the injection rates into the atmosphere of a variety of elements as a function of altitude, integrated over the meteoroid mass and velocity distributions. The most abundant elements (Fe, Mg and Si have peak injection rates around 85 km, with Na and K about 8 km higher. The more refractory element Ca ablates around 82 km with a Na:Ca ratio of 4:1, which does therefore not explain the depletion of atomic Ca to Na, by more than 2 orders of magnitude, in the upper mesosphere. Diffusion of the most volatile elements (Na and K does not appear to be rate-limiting except in the fastest meteoroids. Non-thermal sputtering causes ~35% mass loss from the fastest (~60–70 km s−1 and smallest (10−17–10

  15. Thermochemical Ablation Analysis of the Orion Heatshield

    Sixel, William

    2015-01-01

    The Orion Multi-Purpose Crew Vehicle will one day carry astronauts to the Moon and beyond, and Orion's heatshield is a critical component in ensuring their safe return to Earth. The Orion heatshield is the structural component responsible for absorbing the intense heating environment caused by re-entry to Earth's atmosphere. The heatshield is primarily composed of Avcoat, an ablative material that is consumed during the re-entry process. Ablation is primarily characterized by two processes: pyrolysis and recession. The decomposition of in-depth virgin material is known as pyrolysis. Recession occurs when the exposed surface of the heatshield reacts with the surrounding flow. The Orion heatshield design was changed from an individually filled Avcoat honeycomb to a molded block Avcoat design. The molded block Avcoat heatshield relies on an adhesive bond to keep it attached to the capsule. In some locations on the heatshield, the integrity of the adhesive bond cannot be verified. For these locations, a mechanical retention device was proposed. Avcoat ablation was modelled in CHAR and the in-depth virgin material temperatures were used in a Thermal Desktop model of the mechanical retention device. The retention device was analyzed and shown to cause a large increase in the maximum bondline temperature. In order to study the impact of individual ablation modelling parameters on the heatshield sizing process, a Monte Carlo simulation of the sizing process was proposed. The simulation will give the sensitivity of the ablation model to each of its input parameters. As part of the Monte Carlo simulation, statistical uncertainties on material properties were required for Avcoat. Several properties were difficult to acquire uncertainties for: the pyrolysis gas enthalpy, non-dimensional mass loss rate (B´c), and Arrhenius equation parameters. Variability in the elemental composition of Avcoat was used as the basis for determining the statistical uncertainty in pyrolysis gas

  16. Plume collimation for laser ablation electrospray ionization mass spectrometry

    Vertes, Akos; Stolee, Jessica A.

    2016-06-07

    In various embodiments, a device may generally comprise a capillary having a first end and a second end; a laser to emit energy at a sample in the capillary to ablate the sample and generate an ablation plume in the capillary; an electrospray apparatus to generate an electrospray plume to intercept the ablation plume to produce ions; and a mass spectrometer having an ion transfer inlet to capture the ions. The ablation plume may comprise a collimated ablation plume. The device may comprise a flow cytometer. Methods of making and using the same are also described.

  17. Plume collimation for laser ablation electrospray ionization mass spectrometry

    Vertes, Akos; Stolee, Jessica A.

    2014-09-09

    In various embodiments, a device may generally comprise a capillary having a first end and a second end; a laser to emit energy at a sample in the capillary to ablate the sample and generate an ablation plume in the capillary; an electrospray apparatus to generate an electrospray plume to intercept the ablation plume to produce ions; and a mass spectrometer having an ion transfer inlet to capture the ions. The ablation plume may comprise a collimated ablation plume. The device may comprise a flow cytometer. Methods of making and using the same are also described.

  18. The differential hippocampal phosphoproteome of Apodemus sylvaticus paralleling spatial memory retrieval in the Barnes maze.

    Li, Lin; Csaszar, Edina; Szodorai, Edit; Patil, Sudarshan; Pollak, Arnold; Lubec, Gert

    2014-05-01

    Protein phosphorylation is a well-known and well-documented mechanism in memory processes. Although a large series of protein kinases involved in memory processes have been reported, information on phosphoproteins is limited. It was therefore the aim of the study to determine a partial and differential phosphoproteome along with the corresponding network in hippocampus of a wild caught mouse strain with excellent performance in several paradigms of spatial memory. Apodemus sylvaticus mice were trained in the Barnes maze, a non-invasive test system for spatial memory and untrained mice served as controls. Animals were sacrificed 6h following memory retrieval, hippocampi were taken, proteins extracted and in-solution digestion was carried out with subsequent iTRAQ double labelling. Phosphopeptides were enriched by a TiO2-based method and semi-quantified using two fragmentation principles on the LTQ-orbitrap Velos. In hippocampi of trained animals phosphopeptide levels representing signalling, neuronal, synaptosomal, cytoskeletal and metabolism proteins were at least twofold reduced or increased. Furthermore, a network revealing a link to pathways of ubiquitination, the androgen receptor, small GTPase Rab5 and MAPK signaling as well as synucleins was constructed. This work is relevant for interpretation of previous work and the design of future studies on protein phosphorylation in spatial memory.

  19. Intracerebellar vermis histamine facilitates memory consolidation in the elevated T maze model.

    Silva-Marques, Bruna; Gianlorenço, Anna Carolyna Lepesteur; Mattioli, Rosana

    2016-05-01

    Experimental evidence suggests that the cerebellum plays a more complex role in learning than simply regulating the motor response. Rather, it is thought to play a significant role in the consolidation of emotional memory in mice. Due to the difficulty of interpreting fear and anxiety behaviors-the standard methodology for the study of the histaminergic system and emotional memory-in mice, we propose a behavioral assessment of mice subjected to the Elevated T-maze after histamine microinjection of the cerebellar vermis. Young male Swiss albino mice weighing 25-35g were used. In addition, locomotor activity was tested in an open field test. Our data suggest that histamine did not affect memory consolidation during escape or open field behavior at the doses used in this study. However, we observed a significant increase in inhibitory avoidance on the second day in animals receiving a dose of 6.8nmol/0.5μl, suggesting that histamine facilitates the consolidation of inhibitory avoidance in mice.

  20. Effects of intracerebroventricular injection of alpha-fluoromethylhistidine on radial maze performance in rats.

    Chen, Z; Sugimoto, Y; Kamei, C

    1999-11-01

    The effects of alpha-fluoromethylhistidine (alpha-FMH) on spatial cognition were investigated using the eight-arm radial maze paradigm in rats. Intracerebroventricular (ICV) injection of alpha-FMH resulted in spatial memory deficits characterized by an increase in the number of total errors (TE) and a decrease in the number of initial correct responses (ICR). There was a strong correlation between increases in the number of TE and decreases in histamine contents of the cortex and hippocampus regions of the brain, which are known to participate in learning and memory. On the other hand, both histamine (50-100 ng, ICV) and thioperamide (10 microg, ICV) significantly ameliorated the memory deficit induced by alpha-FMH. However, metoprine showed no significant effect on the alpha-FMH-induced memory deficit. Pyrilamine and R-(alpha)-methylhistamine enhanced the memory deficit induced by alpha-FMH, at doses that had no appreciable effect when administered alone. In contrast, no significant influence on alpha-FMH-induced memory deficit was observed with zolantidine.

  1. Effects of caffeine on learning and memory in rats tested in the Morris water maze

    Angelucci M.E.M.

    2002-01-01

    Full Text Available We studied some of the characteristics of the improving effect of the non-specific adenosine receptor antagonist, caffeine, using an animal model of learning and memory. Groups of 12 adult male Wistar rats receiving caffeine (0.3-30 mg/kg, ip, in 0.1 ml/100 g body weight administered 30 min before training, immediately after training, or 30 min before the test session were tested in the spatial version of the Morris water maze task. Post-training administration of caffeine improved memory retention at the doses of 0.3-10 mg/kg (the rats swam up to 600 cm less to find the platform in the test session, P<=0.05 but not at the dose of 30 mg/kg. Pre-test caffeine administration also caused a small increase in memory retrieval (the escape path of the rats was up to 500 cm shorter, P<=0.05. In contrast, pre-training caffeine administration did not alter the performance of the animals either in the training or in the test session. These data provide evidence that caffeine improves memory retention but not memory acquisition, explaining some discrepancies among reports in the literature.

  2. Nicotine improves AF64A-induced spatial memory deficits in Morris water maze in rats.

    Yamada, Kazuo; Furukawa, Satoshi; Iwasaki, Tsuneo; Ichitani, Yukio

    2010-01-18

    Ethylcholine mustard aziridinium ion (AF64A) is a neurotoxic derivative of choline that produces not only long-term presynaptic cholinergic deficits, but also various memory deficits in rats similar to some characteristics observed in Alzheimer's disease patients. This study investigated whether nicotine (NCT) administration attenuated spatial learning deficits induced by intracerebroventricular AF64A treatment. AF64A (6 nmol/6 microl)-or saline (SAL)-treated rats were trained in Morris water maze task. NCT (0.025-0.25mg/kg) was subcutaneously injected 5 min before the training every day. The results showed that moderate dose (0.10mg/kg) of NCT attenuated AF64A-induced prolongation of escape latency. Furthermore, NCT dose-dependently recovered the AF64A-induced decrease of time spent in the target quadrant in the probe test. These results suggest that NCT improves AF64A-induced spatial memory deficits, and thus it is a potential therapeutic agent for the treatment of memory deficits in dementia.

  3. Myristic Acid Produces Anxiolytic-Like Effects in Wistar Rats in the Elevated Plus Maze

    Carlos M. Contreras

    2014-01-01

    Full Text Available A mixture of eight fatty acids (linoleic, palmitic, stearic, myristic, elaidic, lauric, oleic, and palmitoleic acids at similar concentrations identified in human amniotic fluid produces anxiolytic-like effects comparable to diazepam in Wistar rats. However, individual effects of each fatty acid remain unexplored. In Wistar rats, we evaluated the separate action of each fatty acid at the corresponding concentrations previously found in human amniotic fluid on anxiety-like behaviour. Individual effects were compared with vehicle, an artificial mixture of the same eight fatty acids, and a reference anxiolytic drug (diazepam, 2 mg/kg. Myristic acid, the fatty acid mixture, and diazepam increased the time spent in the open arms of the elevated plus maze and reduced the anxiety index compared with vehicle, without altering general locomotor activity. The other fatty acids had no effect on anxiety-like behaviour, but oleic acid reduced locomotor activity. Additionally, myristic acid produced anxiolytic-like effects only when the concentration corresponded to the one identified in human amniotic fluid (30 g/mL but did not alter locomotor activity. We conclude that of the eight fatty acids contained in the fatty acid mixture, only myristic acid produces anxiolytic-like effects when administered individually at a similar concentration detected in human amniotic fluid.

  4. Molecular docking and panicolytic effect of 8-prenylnaringenin in the elevated T-maze.

    Bagatin, Mariane Cristovão; Tozatti, Camila Santos Suniga; Abiko, Layara Akemi; Yamazaki, Diego Alberto dos Santos; Silva, Priscila Rebeca Alves; Perego, Leonardo Martins; Audi, Elisabeth Aparecida; Seixas, Flavio Augusto Vicente; Basso, Ernani Abicht; Gauze, Gisele de Freitas

    2014-01-01

    The purpose of this study was to investigate the effects of the chronic administration of a racemic mixture of 8-prenylnaringenin (8-PN) on rats submitted to the elevated T-maze (ETM) model of generalized anxiety and panic disorders. The selective serotonin (SERT) reuptake inhibitor fluoxetine was used as a positive control. Rat locomotion was assessed in a circular arena following each drug treatment. The administration of racemic 8-PN for 21 d in rats increased one-way escape latencies from the ETM open arm, indicating a panicolytic effect. To evaluate the interactions of 8-PN with monoamine transporters, a docking study was performed for both the R and S configurations of 8-PN towards SERT, norepinephrine (NET) and dopamine transporters (DAT). The application of the docking protocol showed that (R)-8-PN provides greater affinity to all transporters than does the S enantiomer. This result suggests that enantiomer (R)-8-PN is the active form in the in vivo test of the racemic mixture.

  5. The scientific learning approach using multimedia-based maze game to improve learning outcomes

    Setiawan, Wawan; Hafitriani, Sarah; Prabawa, Harsa Wara

    2016-02-01

    The objective of curriculum 2013 is to improve the quality of education in Indonesia, which leads to improving the quality of learning. The scientific approach and supported empowerment media is one approach as massaged of curriculum 2013. This research aims to design a labyrinth game based multimedia and apply in the scientific learning approach. This study was conducted in one of the Vocational School in Subjects of Computer Network on 2 (two) classes of experimental and control. The method used Mix Method Research (MMR) which combines qualitative in multimedia design, and quantitative in the study of learning impact. The results of a survey showed that the general of vocational students like of network topology material (68%), like multimedia (74%), and in particular, like interactive multimedia games and flash (84%). Multimediabased maze game developed good eligibility based on media and material aspects of each value 840% and 82%. Student learning outcomes as a result of using a scientific approach to learning with a multimediabased labyrinth game increase with an average of gain index about (58%) and higher than conventional multimedia with index average gain of 0.41 (41%). Based on these results the scientific approach to learning by using multimediabased labyrinth game can improve the quality of learning and increase understanding of students. Multimedia of learning based labyrinth game, which developed, got a positive response from the students with a good qualification level (75%).

  6. Electrolytic Effects During Tissue Ablation by Electroporation.

    Rubinsky, Liel; Guenther, Enric; Mikus, Paul; Stehling, Michael; Rubinsky, Boris

    2016-10-01

    Nonthermal irreversible electroporation is a new tissue ablation technique that consists of applying pulsed electric fields across cells to induce cell death by creating permanent defects in the cell membrane. Nonthermal irreversible electroporation is of interest because it allows treatment near sensitive tissue structures such as blood vessels and nerves. Two recent articles report that electrolytic reaction products at electrodes can be combined with electroporation pulses to augment and optimize tissue ablation. Those articles triggered a concern that the results of earlier studies on nonthermal irreversible electroporation may have been tainted by unaccounted for electrolytic effects. The goal of this study was to reexamine previous studies on nonthermal irreversible electroporation in the context of these articles. The study shows that the results from some of the earlier studies on nonthermal irreversible electroporation were affected by unaccounted for electrolysis, in particular the research with cells in cuvettes. It also shows that tissue ablation ascribed in the past to irreversible electroporation is actually caused by at least 3 different cytotoxic effects: irreversible electroporation without electrolysis, irreversible electroporation combined with electrolysis, and reversible electroporation combined with electrolysis. These different mechanisms may affect cell and tissue ablation in different ways, and the effects may depend on various clinical parameters such as the polarity of the electrodes, the charge delivered (voltage, number, and length of pulses), and the distance of the target tissue from the electrodes. Current clinical protocols employ ever-increasing numbers of electroporation pulses to values that are now an order of magnitude larger than those used in our first fundamental nonthermal irreversible electroporation studies in tissues. The different mechanisms of cell death, and the effect of the clinical parameters on the mechanisms may

  7. Silicon-Class Ablators for NIC Ignition Capsules

    Ho, Darwin; Salmonson, Jay; Haan, Steve

    2012-10-01

    We present design studies using silicon-class ablators (i.e., Si, SiC, SiB6, and SiB14) for NIC ignition capsules. These types of ablators have several advantages in that they: (a) require no internal dopant layers and are robust to M-band radiation; (b) have smooth outer surfaces; (c) have stable fuel-ablator interface; and (d) have good 1-D performance. The major disadvantage for some of the ablators in this class is the relatively smaller ablation stabilization. Consequently, the ablator is more susceptible to breakup caused by RT instabilities. However, smoother outer surfaces on this class of ablators can reduce the effect of RT instabilities. 2-D simulations of SiC ablators show ignition failure despite smooth surfaces and good 1-D performance. But SiB6 and SiB14 ablators exhibit promising behaviors. SiB6 (SiB14) ablators have high 1-D ignition margin and high peak core hydrodynamic pressure 880 (900) Gbar. The ablation scale length for SiB6 is longer than that for SiC and for SiB14 is comparable to that of plastic. Therefore, we expect acceptable performance for SiB6 and less RT growth for SiB14. 2-D simulations are now in progress.

  8. Dietary early-life exposure to contaminated eels does not impair spatial cognitive performances in adult offspring mice as assessed in the Y-maze and the Morris water maze.

    Dridi, Imen; Leroy, Delphine; Guignard, Cédric; Scholl, Georges; Bohn, Torsten; Landoulsi, Ahmed; Thomé, Jean-Pierre; Eppe, Gauthier; Soulimani, Rachid; Bouayed, Jaouad

    2014-12-01

    Many environmental contaminants are introduced via the diet and may act as neurotoxins and endocrine disrupters, especially influencing growing organisms in early life. The purpose of this study was to examine whether dietary exposure of dams to fish naturally contaminated with xenobiotics, especially with polychlorinated biphenyls (PCBs) and heavy metals (e.g., mercury and lead), resulted in cognitive function deficits in adult offspring mice. Daily, four groups of dams (n = 10/group) ingested standard diet plus paste with/without eels, during gestation and lactation, from gestational day (GD) six until post natal day (PND) 21 (weaning). Dams orally ingested a standardized amount of eel (0.8 mg kg(-1) d(-1)) containing the six non-dioxin-like (NDL) PCBs (Σ6 NDL-PCBs: 28, 52, 101, 138, 153, and 180) at 0, 85, 216, and 400 ng kg(-1) d(-1). Results showed that early-life exposure to contaminated eels did not (compared to non-exposed controls) impair immediate working memory in the Y-maze in the offspring assessed at PND 38. Furthermore, it did not significantly impact spatial learning and retention memory as measured in the Morris water maze in adult offspring mice (PND 120-123). Our results suggest that perinatal exposure to contaminated eels does not affect spatial cognitive performances, as assessed by the Y-maze and Morris water maze at adult age. Adverse effects of xenobiotics reported earlier might be camouflaged by beneficial eel constituents, such as n-3 fatty acids. However, additional studies are needed to differentiate between potential positive and negative effects following consumption of food items both rich in nutrients and contaminants.

  9. Un cas particulier du scénario dans l'apprentissage des langues : le labyrinthe (action maze Action Mazes: a special case of the scenario for language learning

    Joseph Rézeau

    2008-03-01

    Full Text Available En didactique des langues l'approche actionnelle et les scénarios sont d'actualité, en lien avec les Tice (Technologies de l'Information et de la Communication pour l'Enseignement. Cependant, des activités de type labyrinthe (action mazes, courantes dans les années 1980 et souvent portées sur les micro-ordinateurs de l'époque, semblent quelque peu tombées dans l'oubli. Cet article entend montrer qu'il est relativement aisé de concevoir et de réaliser de telles activités sur une plateforme d'enseignement à distance telle que Moodle. Nous analyserons également l'impact d'une activité de type labyrinthe sur une population d'étudiants dans le cadre d'un enseignement d'anglais de type Lansad (langues pour spécialistes d'autres disciplines.The development of ICT in language teaching concurs with an interest in task-based approaches and scenarios. Surprisingly, however, such activities as "adventure games" and "action mazes" which were quite popular in CALL (Computer Assisted Language Learning in the 1980s seem to have fallen into oblivion. This article aims at demonstrating that it is relatively easy to design and implement "action mazes" on an LMS (Learning Management System such as Moodle. We shall then analyse the impact of an "action maze" learning activity on a population of students of ESP (English for Specific Purposes.

  10. Tissue temperatures and lesion size during irrigated tip catheter radiofrequency ablation: an in vitro comparison of temperature-controlled irrigated tip ablation, power-controlled irrigated tip ablation, and standard temperature-controlled ablation

    Petersen, H H; Chen, X; Pietersen, A;

    2000-01-01

    in the power-controlled mode with high power and high infusion rate, and is associated with an increased risk of crater formation, which is related to high tissue temperatures. The present study explored the tissue temperatures during temperature-controlled irrigated tip ablation, comparing it with standard......The limited success rate of radiofrequency catheter ablation in patients with ventricular tachycardias related to structural heart disease may be increased by enlarging the lesion size. Irrigated tip catheter ablation is a new method for enlarging the size of the lesion. It was introduced...... temperature-controlled ablation and power-controlled irrigated tip ablation. In vitro strips of porcine left ventricular myocardium were ablated. Temperature-controlled irrigated tip ablation at target temperatures 60 degrees C, 70 degrees C, and 80 degrees C with infusion of 1 mL saline/min were compared...

  11. Ablation of GaN Using a Femtosecond Laser

    刘伟民; 朱荣毅; 钱土雄; 袁述; 张国义

    2002-01-01

    We study the pulsed laser ablation of wurtzite gallium nitride (GaN) films grown on sapphire, using the fem tosecond laser beam at a central wavelength of 800nm as the source for the high-speed ablation of GaN films. By measuring the backscattered Raman spectrum of ablated samples, the dependence of the ablation depth on laser fluence with one pulse was obtained. The threshold laser fluence for the ablation of GaN films was determined to be about 0.25J/cm2. Laser ablation depth increases with the increasing laser fluence until the amount of removed material is not further increased. The ablated surface was investigated by an optical surface interference profile meter.

  12. Wavelength dependence of soft tissue ablation by using pulsed lasers

    Xianzeng Zhang; Shusen Xie; Qing Ye; Zhenlin Zhan

    2007-01-01

    Pulsed laser ablation of soft biological tissue was studied at 10.6-, 2.94-, and 2.08-μm wavelengths. The ablation effects were assessed by means of optical microscope, the ablation crater depths were measured with reading microscope. It was shown that Er:YAG laser produced the highest quality ablation with clear,sharp cuts following closely the patial contour of the incident beam and the lowest fluence threshold. The pulsed CO2 laser presented the moderate quality ablation with the highest ablation efficiency. The craters drilled with Ho:YAG laser were generally larger than the incident laser beam spot, irregular in shape, and clearly dependent on the local morphology of biotissue. The blation characteristics, including fluence threshold and ablation efficiency, varied substantially with wavelength. It is not evident that water is the only dominant chromophore in tissue.

  13. Radio frequency ablation in drug resistant chemotherapy-induced peripheral neuropathy: A case report and review of literature

    Naveen Yadav

    2010-01-01

    Full Text Available Chemotherapy-induced peripheral neuropathy (CIPN is a frequently encountered complication. It can result from a host of agents. Various modalities of treatment have been advocated, of which a novel method is radio frequency ablation. A 63-year-old male, a case of carcinoma prostrate with bone metastases, presented with tingling and numbness in right upper limb. He was given morphine, gabapentin and later switched to pregabalin, but medications provided only minor relief. Initially he was given stellate ganglion block, then radiofrequency ablation of dorsal root ganglion was done, but it failed to provide complete relief. Pulsed radiofrequency ablation (PRF was then done for 90 seconds; two cycles each in both ulnar and median nerve. After the procedure the patient showed improvement in symptoms within four to five hours and 80% relief in symptoms. We conclude that PRF can be used for the treatment of drug resistant CIPN.

  14. The APPLE Score – A Novel Score for the Prediction of Rhythm Outcomes after Repeat Catheter Ablation of Atrial Fibrillation

    Kornej, Jelena; Hindricks, Gerhard; Arya, Arash; Sommer, Philipp; Husser, Daniela; Bollmann, Andreas

    2017-01-01

    Background Arrhythmia recurrences after catheter ablation occur in up to 50% within one year but their prediction remains challenging. Recently, we developed a novel score for the prediction of rhythm outcomes after single AF ablation demonstrating superiority to other scores. The current study was performed to 1) prove the predictive value of the APPLE score in patients undergoing repeat AF ablation and 2) compare it with the CHADS2 and CHA2DS2-VASc scores. Methods Rhythm outcome between 3–12 months after AF ablation were documented. The APPLE score (one point for Age >65 years, Persistent AF, imPaired eGFR (Leipzig Heart Center AF Ablation Registry (60±10 years, 65% male, 70% paroxysmal AF) undergoing repeat AF catheter ablation were included. Arrhythmia recurrences were observed in 133 patients (35%). While the CHADS2 (AUC 0.577, p = 0.037) and CHA2DS2-VASc scores (AUC 0.590, p = 0.015) demonstrated low predictive value, the APPLE score showed better prediction of arrhythmia recurrences (AUC 0.617, p = 0.002) than other scores (both p<0.001). Compared to patients with an APPLE score of 0, the risk (OR) for arrhythmia recurrences was 2.9, 3.0 and 6.0 (all p<0.01) for APPLE scores 1, 2, or ≥3, respectively. Conclusions The novel APPLE score is superior to the CHADS2 and CHA2DS2-VASc scores for prediction of rhythm outcomes after repeat AF catheter ablation. It may be helpful to identify patients with low, intermediate or high risk for recurrences after repeat procedure. PMID:28085921

  15. Ultrasound guided percutaneous microwave ablation of benign thyroid nodules: Safety and imaging follow-up in 222 patients

    Yue, Wenwen [Binzhou Medical University, #346 Guan-hai Road, Lai-shan, Yantai, Shandong 264003 (China); Wang, Shurong, E-mail: 7762808@sina.com [Department of Ultrasound, Muping Area People' s Hospital, #629 Nan-hua Street, Mu-ping, Yantai, Shandong 264100 (China); Wang, Bin [Binzhou Medical University, #346 Guan-hai Road, Lai-shan, Yantai, Shandong 264003 (China); Xu, Qingling; Yu, Shoujun; Yonglin, Zhang; Wang, Xiju [Department of Ultrasound, Muping Area People' s Hospital, #629 Nan-hua Street, Mu-ping, Yantai, Shandong 264100 (China)

    2013-01-15

    Objective: Microwave ablation is a minimally invasive technique that has been used to treat benign and malignant tumors of liver, lung and kidney. Towards thyroid nodules, only a few cases are reported so far. The aim of the study was to investigate the effectiveness and safety of ultrasound-guided percutaneous microwave ablation in the treatment of benign thyroid nodules with a large sample. Materials and methods: A total of 477 benign thyroid nodules in 222 patients underwent microwave ablation in our department from July 2009 to March 2012. Microwave ablation was carried out using microwave antenna (16G) under local anesthesia. Nodule volume, thyroid function and clinical symptoms were evaluated before treatment and at 1, 3, more than 6 months. The study was ethics committee approved and written informed consents were obtained from all patients. Results: All thyroid nodules significantly decreased in size after microwave ablation. A 6-month follow-up was achieved in 254 of 477 nodules, and the mean decrease in the volume of thyroid nodules was from 2.13 ± 4.42 ml to 0.45 ± 0.90 ml, with a mean percent decrease of 0.65 ± 0.65. A volume-reduction ratio greater than 50% was observed in 82.3% (209/254) of index nodules, and 30.7% (78/254) of index nodules disappeared 6-month after the ablation. The treatment was well tolerated and no major complications were observed except pain and transient voice changes. Conclusions: Microwave ablation seems to be a safe and effective technique for the treatment of benign thyroid nodules. Further prospective randomized studies are needed to define the role of the procedure in the treatment of thyroid nodules.

  16. Alpha7 nicotinic acetylcholine receptor activation ameliorates scopolamine-induced behavioural changes in a modified continuous Y-maze task in mice.

    Redrobe, John P; Nielsen, Elsebet Ø; Christensen, Jeppe K; Peters, Dan; Timmermann, Daniel B; Olsen, Gunnar M

    2009-01-01

    The alpha7 (alpha7) nicotinic acetylcholine receptor may represent a drug target for the treatment of disorders associated with working memory/attentional dysfunction. We investigated the effects of three distinct alpha7 nicotinic acetylcholine receptor agonists: 2-methyl-5-(6-phenyl-pyridazin-3-yl)-octahydro-pyrrolo[3,4-c]pyrrole (A-582941; 0.01-0.1 mg/kg), 4-bromophenyl 1,4-diazabicyclo(3.2.2) nonane-4-carboxylate (SSR180711; 0.3-3 mg/kg) and N-[(3R)-1-azabicyclo[2.2.2]oct-3-yl]-4-chlorobenzamide (PNU-282987; 1-10 mg/kg), on scopolamine-induced deficits in a modified Y-maze procedure. Mice were forced to choose one of two visually distinct arms, and were confined there for a 5 min exploration period before being allowed to explore both arms for a 2 min test session, immediately thereafter. The time spent in each arm, entries and total distance travelled were recorded using an automated system. Characterisation experiments showed that scopolamine-treated (1 mg/kg) mice spent less time exploring the unfamiliar arm, when compared with vehicle-treated animals. Combination experiments showed that all three alpha7 agonists ameliorated scopolamine-induced changes in unfamiliar arm exploration. In conclusion, the present data support the idea that alpha7 nicotinic acetylcholine receptors may represent an interesting target for the treatment of conditions associated with attentional/working memory dysfunction.

  17. Real time echo-guided endolaser for thermal ablation without perivenous tumescence

    Ricardo José Gaspar

    2015-12-01

    Full Text Available Abstract Background There is no consensus in the medical literature on the ideal procedure for endovenous laser application. Objective To assess the safety and efficacy of real time echo-guided endovenous laser for thermal ablation of great saphenous vein (GSV incompetence, without perivenous tumescence. Methods Thirty-four limbs of patients with CEAP clinical scores of 2 to 6 and bilateral incompetence of the saphenofemoral junction (SFJ and GSV, confirmed by Echo-Doppler, underwent endovenous laser therapy and were followed for 1 year. Laser ablation was performed using a 600 µ bare optical fiber introduced endovenously close to the malleolus along the full extent of the GSV in an anterograde direction, using a standardized echo-Doppler-guided AND? 15 watt continuous mode 980 nm diode laser with real-time monitoring of thermal ablation of the whole target vein. Adverse effects and complications were recorded. Results Hyperesthesia, cellulitis, and fibrous cord, all transitory, developed in 2.9% of the 34 limbs treated; 8.8% developed hypoesthesia in the perimalleolar region, which was transitory and had no clinical consequences; there were no cases of deep venous thrombosis. Immediate occlusion was achieved in 100% of the 34 saphenous veins that underwent photocoagulation, although one exhibited recanalization without reflux at 1-month follow-up. After 6 months and 1 year, occlusion was 100% according to echo-Doppler findings. Conclusions Real-time echo-guided 980 nm endovenous laser ablation without perivenous tumescence provided controlled thermal ablation with safe, effective, immediate and medium-term GSV occlusion and can therefore be recommended as a method for the treatment of chronic venous disease.

  18. Safety and Efficacy of EUS-Guided Ethanol Ablation for Treating Small Solid Pancreatic Neoplasm.

    Paik, Woo Hyun; Seo, Dong Wan; Dhir, Vinay; Wang, Hsiu-Po

    2016-01-01

    The strategy for treating small borderline malignant pancreatic neoplasms--such as neuroendocrine tumor (NET) and solid pseudopapillary neoplasm (SPN)--is surgical resection. However, pancreatic resection of these lesions still causes significant morbidity. We evaluated the safety and efficacy of EUS-guided ethanol ablation to treat small solid pancreatic neoplasms. A total of 8 patients with small borderline malignant pancreatic neoplasms and co-morbidities who refused surgery were included. We identified 2 cases of nonfunctioning NET, 3 cases of insulinomas, 1 case of gastrinoma, and 2 cases of SPN. EUS-guided ethanol ablation was performed, and treatment outcomes were assessed with clinical symptom, hormone assay, and imaging study. The mean tumor diameter was 15  mm (range, 7-29  mm), and the median volume of injected ethanol was 2.8  mL (range, 1.2-10.5  mL). There was 1 severe acute pancreatitis after EUS-guided ethanol ablation with 20-gauge CPN needle. During follow-up (median 16.5 months), 6 patients achieved treatment success; however, 2 patients (1 nonfunctioning NET and 1 SPN) still had persistent tumors. The patient with persistent SPN underwent surgical resection and the histopathological results showed peripancreatic infiltration with perineural invasion. Among 6 patients who achieved initial treatment success, 1 patient experienced tumor recurrence within 15 months and underwent repeated EUS-guided ethanol ablation. In conclusion, EUS-guided ethanol ablation therapy is a promising option for patients with small solid pancreatic neoplasm. Multiple sessions or surgical interventions may be required if there is a recurrent or persistent mass, and procedure-related adverse events must be carefully monitored.

  19. A novel technique for orchiectomy and scrotal ablation in the sugar glider (Petaurus breviceps).

    Morges, Michelle A; Grant, Krystan R; MacPhail, Catriona M; Johnston, Matthew S

    2009-03-01

    In this report, we describe a simple, safe, and efficacious technique for orchiectomy and scrotal ablation with the use of a carbon dioxide light amplification by stimulated emission of radiation (laser) in sugar gliders (Petaurus breviceps). The study population included nine sugar gliders, ages 2-24 mo, presented for orchiectomy. After induction of general anesthesia, orchiectomy and scrotal ablation were performed by severing the scrotal stalk with the laser. All sugar gliders were discharged the same day. Mean anesthesia time was 6.09 +/- 0.94 min. Mean surgery time was 15.11 +/- 8.39 sec, and mean recovery time was 4.11 +/- 3.60 min. With an outlier removed, mean recovery time was 2.95 +/- 1.03 min. No serious postoperative surgical complications were observed. The technique described is a simple procedure with rapid surgical and recovery times that has the potential to become the standard procedure for orchiectomy and scrotal ablation in sugar gliders.

  20. Maze solving automatons for self-healing of open interconnects: Modular add-on for circuit boards

    Nair, Aswathi; Raghunandan, Karthik; Yaswant, Vaddi; Sambandan, Sanjiv, E-mail: sanjiv@iap.iisc.ernet.in, E-mail: ssanjiv@isu.iisc.ernet.in [Department of Instrumentation and Applied Physics, Indian Institute of Science, Malleswaram, Bangalore 560012 (India); Pillai, Sreelal S. [Vikram Sarabhai Space Center, Indian Space Research Organization, Trivandrum 695022 (India)

    2015-03-23

    We present the circuit board integration of a self-healing mechanism to repair open faults. The electric field driven mechanism physically restores fractured interconnects in electronic circuits and has the ability to solve mazes. The repair is performed by conductive particles dispersed in an insulating fluid. We demonstrate the integration of the healing module onto printed circuit boards and the ability of maze solving. We model and perform experiments on the influence of the geometry of conductive particles as well as the terminal impedances of the route on the healing efficiency. The typical heal rate is 10 μm/s with healed route having mean resistance of 8 kΩ across a 200 micron gap and depending on the materials and concentrations used.

  1. Behavioral effects of "vehicle" microinjected into the dorsal periaqueductal grey of rats tested in the elevated plus maze

    Matheus M.G.

    1997-01-01

    Full Text Available To investigate the behavioral effects of different vehicles microinjected into the dorsal periaqueductal grey (DPAG of male Wistar rats, weighing 200-250 g, tested in the elevated plus maze, animals were implanted with cannulas aimed at this structure. One week after surgery the animals received microinjections into the DPAG of 0.9% (w/v saline, 10% (v/v dimethyl sulfoxide (DMSO, 2% (v/v Tween-80, 10% (v/v propylene glycol, or synthetic cerebrospinal fluid (CSF. Ten min after the injection (0.5 µl the animals (N = 8-13/group were submitted to the elevated plus maze test. DMSO significantly increased the number of entries into both the open and enclosed arms when compared to 0.9% saline (2.7 ± 0.8 and 8.7 ± 1.3 vs 0.8 ± 0.3 and 5.1 ± 0.9, respectively, Duncan test, P<0.05, and tended to increase enclosed arm entries as compared to 2% Tween-80 (8.7 ± 1.3 vs 5.7 ± 0.9, Duncan test, P<0.10. In a second experiment no difference in plus maze exploration was found between 0.9% saline- or sham-injected animals (N = 11-13/group. These results indicate that intra-DPAG injection of some commonly used vehicles such as DMSO, saline or Tween-80 affects the exploratory activity of rats exposed to the elevated plus maze in statistically different manners

  2. Effects of Early Training and Nicotine Treatment on the Performance of Male NMRI Mice in the Water Maze

    2003-01-01

    This research aimed to evaluate the effect of nicotine treatment and prior training on a spatial learning task in differently aged NMRI male mice. In a longitudinal study, mice were randomly assigned to one of 14 experimental groups receiving different combinations of chronically injected nicotine (0.35 mg/kg) administered for 10 days (5 days before and during 5 days acquisition of task) or control treatments and training in the water maze at different ages. The ...

  3. Short-term versus long-term water maze training effects on hippocampal neuronal synaptic plasticity in a rat model of senile dementia

    Guogui Li

    2008-01-01

    BACKGROUND: Changes in synaptic plasticity might underlie senile dementia, and might be the neurobiological basis for learning and memory dysfunctions in patients with Alzheimer's Disease. OBJECTIVE: To investigate the effects of water maze training on hippocampal neuronal synaptic plasticity in rats with senile dementia, and to compare changes in synaptic plasticity between short- and long-term water maze training sessions.DESIGN, TIME AND SETTING: A randomized, controlled, neuromorphological observation with animal models of senile dementia was performed at the laboratory of College of Pharmacy, Chongqing Medical University between November 2006 and April 2007.MATERIALS: Fifty male, Sprague Dawley rats were randomized into five groups, with 10 rats per group: model, control, sham-operated, short-term water maze training, and long-term water maze training. METHODS: In the model group, senile dementia was induced by fimbria-fornix lesion method. The control rats remained untreated. In the sham-operated group, water maze training was performed without fimbria-fornix lesion induction. Rats from the short-term water maze training group underwent 20-day water maze training from day 26 after fimbria-fornix lesion induction. The long-term water maze training group underwent 40-day water maze training beginning at day 6 following fimbria-fornix lesion induction. Beginning at day 41, each group underwent 5-day spatial learning and memory training. MAIN OUTCOME MEASURES: Following experimentation, the morphological parameters of synapses, including synaptic numerical density, synaptic surface density, and the average synapse size were stereologically measured. Through the use of an electron microscope, synaptic morphological changes in the hippocampai CA3 region were observed.RESULTS: Compared with the control group, synaptic numerical and surface densities were significantly decreased in the model group (P < 0.01). Synaptic numerical and surface densities significantly

  4. Dental Procedures.

    Ramponi, Denise R

    2016-01-01

    Dental problems are a common complaint in emergency departments in the United States. There are a wide variety of dental issues addressed in emergency department visits such as dental caries, loose teeth, dental trauma, gingival infections, and dry socket syndrome. Review of the most common dental blocks and dental procedures will allow the practitioner the opportunity to make the patient more comfortable and reduce the amount of analgesia the patient will need upon discharge. Familiarity with the dental equipment, tooth, and mouth anatomy will help prepare the practitioner for to perform these dental procedures.

  5. Chlorpheniramine facilitates inhibitory avoidance in teleosts submitted to telencephalic ablation

    F.R. Faganello

    2008-05-01

    Full Text Available The present study investigated the involvement of H(1 histaminegic receptor on the acquisition of inhibitory avoidance in Carassius auratus submitted to telencephalic ablation. The fish were submitted to telencephalic ablation 5 days before the experiment. The inhibitory avoidance procedure included 1 day for habituation, 3 days for training composed of 3 trials each (1st day: T1, T2, T3; 2nd day: 2T1, 2T2, 2T3; 3rd day: 3T1, 3T2, 3T3 and 1 day for test. On training days, the fish were placed in a white compartment, after 30 s the door was opened. When the fish crossed to a black compartment, a weight was dropped (aversive stimuli. Immediately after the third trial, on training days, the fish received, intraperitoneally, one of the pharmacological treatments (saline (N = 20, 8 (N = 12 or 16 (N = 13 µg/g chlorpheniramine, CPA. On the test day, the time to cross to the black compartment was determined. The latency of the saline group increased significantly only on the 3rd trial of the 2nd training day (mean ± SEM, T1 (50.40 ± 11.69, 2T3 (226.05 ± 25.01; ANOVA: P = 0.0249, Dunn test: P < 0.05. The group that received 8 µg/g CPA showed increased latencies from the 2nd training day until the test day (T1 (53.08 ± 17.17, 2T2 (197.75 ± 35.02, test (220.08 ± 30.98; ANOVA: P = 0.0022, Dunn test: P < 0.05. These results indicate that CPA had a facilitating effect on memory. We suggest that the fish submitted to telencephalic ablation were able to learn due to the local circuits of the mesencephalon and/or diencephalon and that CPA interferes in these circuits, probably due an anxiolytic-like effect.

  6. Anxiolytic effects of short- and long-term administration of cacao mass on rat elevated T-maze test.

    Yamada, Takashi; Yamada, Yasushi; Okano, Yasuyo; Terashima, Takehiko; Yokogoshi, Hidehiko

    2009-12-01

    We demonstrated the effects of short- and long-term administration of cacao mass on anxiety in the elevated T-maze test, which is an animal model of anxiety. In the first study, we administered cacao mass (100 mg/100 g body weight) per os and immediately performed the elevated T-maze test. Short-term cacao mass significantly abolished delayed avoidance latency compared with the control but did not change escape latency. This result suggested that cacao mass administration reduced conditional fear-relating behavior. Short-term cacao mass administration did not affect the concentration of brain monoamines, emotion-related neurotransmitters such as norepinephrine, serotonin and dopamine, in the rat brain. In the next study, we fed a cacao mass-containing diet to rats for 2 weeks and performed the elevated T-maze test. Contrary to short-term administration, chronic consumption of cacao mass tended to increase avoidance latency and did not change escape latency. Brain serotonin concentration and its turnover were enhanced by chronic consumption of cacao mass. These results suggested that chronic consumption of cacao did not affect fear-related behavior but was involved in brain monoamine metabolism. In conclusion, we suggest that short-term cacao mass consumption showed an anxiolytic effect but chronic consumption did not.

  7. The effect of Resveratrol flavonoid on learning and memory in passive avoidance and Y maze in diabetic rat

    Sima Nasri

    2014-04-01

    Full Text Available Background: Diabetes type I is accompanied with disturbances in cognitive skills, memory and learning. In this research, we evaluated the effect of resveratrol chronic treatment on learning and memory in diabetic male rats. Material and Methods: Rats were divided into 4 groups: control, resveratrol-treated control, diabetic and resveratrol-treated diabetic groups. We used streptozotosin for inducing diabetes. Resveratrol (10mg/kg I.p. was administered for 8 weeks. For evaluation of learning and memory, passive avoidance test and Y-maze task were used. For Statistical analysis, SPSS software and paired T-test and one-way ANOVA were used. Results: Resveratrol decreased serum glucose in diabetic rats (P<0.01. In passive avoidance learning, there wasn’t any significant difference in initial latency between diabetic and treated- diabetic group. Also, a significant decrease of step latency was observed in diabetic and treated diabetic rats (P<0.01. In Y maze, Resveratrol improved alternation percentage in diabetic rats. Conclusion: Probably due to different mechanism of long term and short term memory, long term resveratrol treatment didn’t improve memory and learning in passive avoidance learning. In Y maze, method for determining the spatial memory, resveratrol improved spatial memory in diabetic rats. Resveratrol not only regulates glucose in diabetic rats but also it improves short term memory.

  8. Successful non-operative management of left atrioesophageal fistula following catheter ablation.

    Shiraishi, Manabu; Morita, Hideki; Muramatsu, Kenichi; Sato, Akira; Nitta, Junichi; Yamaguchi, Atsushi; Adachi, Hideo

    2014-08-01

    Atrioesophageal fistula (AEF) is a potentially lethal complication of catheter radiofrequency ablation for atrial fibrillation. A 49-year-old man with paroxysmal atrial fibrillation who underwent catheter ablation around the pulmonary vein was admitted 31 days after the procedure, suffering seizures and fever. Magnetic resonance imaging of the brain showed ischemia and multiple lesions of acute infarction in the right occipital lobe of the cerebrum. Computed tomography (CT) of the chest showed a small accumulation of air between the posterior left atrium and the esophagus, suggesting an AEF. Endoscopic snaring of the esophageal mucosa, repeated a few times, supported by nil by mouth and antibiotic therapy, resulted in improvement of his condition with no recurrence of symptoms. Subsequent chest CT scans confirmed disappearance of the leaked air and the patient was discharged home 45 days after admission with no neurological compromise.

  9. Donor Kidney With Renal Cell Carcinoma Successfully Treated With Radiofrequency Ablation

    Christensen, S F; Hansen, Jesper Melchior

    2015-01-01

    BACKGROUND: The risk of donor-transmitted cancer is evident. CASE REPORT: We report the case of a 69-year-old woman who was transplanted with a kidney from a deceased donor. Four days after transplantation a routine ultrasound scan revealed a 3-cm tumor in the middle-upper pole of the allograft....... A biopsy showed the tumor to be papillary renal cell carcinoma. The patient was treated with radiofrequency ablation. This procedure was complicated by the development of a cutaneous fistula and open surgery was done with resection of an area of necrosis in the kidney and of the fistula. The maintenance.......04 mg/dL]). CONCLUSIONS: To the best of our knowledge, this is the first case in which a donor-transmitted tumor was diagnosed in the renal allograft only 4 days after transplantation and subsequently treated successfully with radiofrequency ablation....

  10. Effects of acute and chronic nicotine on elevated plus maze in mice: involvement of calcium channels.

    Biala, Grazyna; Budzynska, Barbara

    2006-05-30

    The current experiments examined the anxiety-related effects of acute and repeated nicotine administration using the elevated plus maze test in mice. Nicotine (0.1 mg/kg s.c., 5 and 30 min after injection; 0.5 mg/kg, s.c., 5 min after injection) had an anxiogenic effect, shown by specific decreases in the percentage of time spent on the open arms and in the percentage of open arm entries. Tolerance developed to this anxiogenic action after 6 days of daily nicotine administration (0.1 mg/kg, s.c.). Five minutes after the seventh injection, an anxiolytic effect was observed, i.e., specific increases in the percentage of time spent on the open arms and in the percentage of open arm entries. L-type voltage-dependent calcium channel antagonists nimodipine (5 and 10 mg/kg, i.p.), flunarizine (5 and 10 mg/kg, i.p.), verapamil (5, 10, 20 mg/kg) and diltiazem (5, 10, 20 mg/kg, i.p.) were also injected prior to an acute low dose of nicotine or to each injection of chronic nicotine. Our results revealed that calcium channel blockers dose-dependently attenuated both an anxiogenic effect of nicotine as well as the development of tolerance to this effect. Our results suggest that neural calcium-dependent mechanisms are involved in the anxiety-related responses to acute and chronic nicotine injection that may ultimately lead to addiction and smoking relapse in human smokers.

  11. Flavonoids from Tilia americana with anxiolytic activity in plus-maze test.

    Herrera-Ruiz, Maribel; Román-Ramos, Rubén; Zamilpa, Alejandro; Tortoriello, Jaime; Jiménez-Ferrer, J Enrique

    2008-07-23

    The aerial parts of Tilia americana var. mexicana (Schltdl) Hardin (Tiliaceae) have been widely used in Mexican traditional medicine to relieve sleeplessness, headache, and nervous excitement. The anxiolytic effect of four extracts and several flavonoid fractions from the bracts of Tilia americana subsp.mexicana, var. mexicana (Schltdl) Hardin or Tilia mexicana (Tiliaceae) was studied. Administration of 100mg/kg of n-hexane, ethyl acetate, and aqueous extracts to elevated plus-maze (EPM)-exposed mice displayed no anxiolytic effect; however, identical doses of methanol extract was able to increase the time percentage that mice spent in the EPM's open arms, as well as the percentage of crossings in the EPM's arms. The dose-response curve produced by methanol extract showed anxiolytic activity since 25mg/kg; animals showed no motor activity alteration in the open field test (OFT). Methanol extract was subjected to a bioassay-guided fractionation to obtain four ascendant polarity fractions (F1-F4) which were administrated at 100mg/kg. Data results indicate that F1 displayed the main anxiolytic effect. The purification of F1 produced a rich flavonoid anxiolytic mixture (F1C). This fraction was purified by RP-18 open chromatographic column to obtain four polar descent fractions: F1C(1), F1C(2), F1C(3), and F1C(4), respectively. Tiliroside was the major ingredient from the active fraction. High performance liquid chromatography analysis indicated that F1C was constituted principally of tiliroside, quercetin, quercitrin, kaempherol, and their glycosides. These results supported the use of Tilia americana in Mexican traditional medicine as well as the anxiolytic effect of a rich flavonoid fraction without affect motor activity.

  12. Androgen insensitive male rats display increased anxiety-like behavior on the elevated plus maze.

    Hamson, Dwayne K; Jones, Bryan A; Csupity, Attila S; Ali, Faezah M; Watson, Neil V

    2014-02-01

    Male rats carrying the testicular feminization mutation (Tfm-affected males) are insensitive to androgens, resulting in a female-typical peripheral phenotype despite possession of inguinal testes that are androgen secretory. Androgen-dependent neural and behavioral processes may likewise show atypical sexual differentiation. Interestingly, these mutant rats display elevated serum corticosterone, suggesting a chronic anxiety phenotype and dysregulated hypothalamic-pituitary-adrenal axis. In order to understand if elevated anxiety-like behavior is a possible mediating variable affecting the display of certain androgen-dependent behaviors, we compared the performance of Tfm-affected males to wild type males and females in the elevated plus maze (EPM). Two well-established indicators of anxiety-like behavior in the EPM were analyzed: total percentage of time spent on the open arms, and the percentage of open arm entries. We also analyzed the total number of open arm entries. Interestingly, Tfm-affected males spent less percentage of time on the open arms than both males and females, suggesting increased anxiety-like behavior. Percentage of open arm entries and the total number of arm entries was comparable between the groups, indicating that the observed decrease in the percentage of time spent on the open arms was not due to a global reduction in exploratory behavior. These data, in contrast to earlier reports, thus implicate androgen receptor-mediated functions in the expression of anxiety behaviors in male rats. Given that anxiety is widely reported as a precipitating factor in depression, studying the role of the androgen receptor in anxiety may give insights into the pathogenesis of major depressive disorder.

  13. Harvard v. Canada: the myc mouse that still squeaks in the maze of biopatent law.

    Deftos, L J

    2001-07-01

    The Canadian Supreme Court will soon make a decision about Harvard University's long-standing application for a Canadian patent on a mouse transgenic for the myc oncogene. That decision could reignite in North America the controversy that continues in Europe and elsewhere to surround the patenting of life forms. The tortuous steps in this 15-year patent maze are marked by the arguments about life patents that attended the U.S. Supreme Court's decision in Diamond v. Chakrabarty. This patent dispute about oil-digesting bacteria cracked open the door for animal patents in the United States and other countries, even though the legal arguments involved were based on patent applications for corn seeds and oysters, not mammals. The patent challenge to the Harvard mouse by the Canadian government now threatens to close this door in Canada. The arguments against life patents are commonly based on moral and religious grounds that regard the sanctity of life and oppose its commodification. The most compelling arguments for such patents are based on the benefits they deliver through commercial exploitation of inventions. The debate about patenting animals has been more heated outside North America and cacaphonic in the Third World. However, the Canadian debate could be amplified by the U.S. Supreme Court's recent entry on the biopatent stage through the side door of a new corn seed patent dispute. A narrow legal analysis by the Canadian Supreme Court would award the mouse patent to Harvard, while a policy analysis might support the government's challenge of the patent. Although the impact of the Harvard mouse patent process in Canada could be just a squeak, opponents of patenting life can mount the myc mouse to once again roar their opposition to animal patents. And the sound could resonate through the arguments about both biopatents and human cloning, with potentially important effects for academia, industry, and the public.

  14. Molecular mechanisms for the destabilization and restabilization of reactivated spatial memory in the Morris water maze

    Kim Ryang

    2011-02-01

    Full Text Available Abstract Background Memory retrieval is not a passive process. Recent studies have shown that reactivated memory is destabilized and then restabilized through gene expression-dependent reconsolidation. Molecular studies on the regulation of memory stability after retrieval have focused almost exclusively on fear memory, especially on the restabilization process of the reactivated fear memory. We previously showed that, similarly with fear memories, reactivated spatial memory undergoes reconsolidation in the Morris water maze. However, the underlying molecular mechanisms by which reactivated spatial memory is destabilized and restabilized remain poorly understood. In this study, we investigated the molecular mechanism that regulates the stability of the reactivated spatial memory. Results We first showed that pharmacological inactivation of the N-methyl-D-aspartate glutamate receptor (NMDAR in the hippocampus or genetic inhibition of cAMP-responsible element binding protein (CREB-mediated transcription disrupted reactivated spatial memory. Finally, we showed that pharmacological inhibition of cannabinoid receptor 1 (CB1 and L-type voltage gated calcium channels (LVGCCs in the hippocampus blocked the disruption of the reactivated spatial memory by the inhibition of protein synthesis. Conclusions Our findings indicated that the reactivated spatial memory is destabilized through the activation of CB1 and LVGCCs and then restabilized through the activation of NMDAR- and CREB-mediated transcription. We also suggest that the reactivated spatial memory undergoes destabilization and restabilization in the hippocampus, through similar molecular processes as those for reactivated contextual fear memories, which require CB1 and LVGCCs for destabilization and NMDAR and CREB for restabilization.

  15. Ablation of steel using picosecond laser pulses in burst mode

    Lickschat, Peter; Demba, Alexander; Weissmantel, Steffen

    2017-02-01

    Results obtained in picosecond laser processing of steel applying the burst mode are presented. Using the burst mode, pulse trains, i.e., bursts, consisting of a number of picosecond pulses with an inter-pulse delay of 12.5 ns and 10 ps pulse duration are applied for material processing. Small cavities with sizes in the range of the laser beam diameter made by single-burst ablation are compared to quadratic cavities of 0.5 × 0.5 mm² produced by multiburst ablation and simultaneous scanning of the laser beam across the steel sample surface. The ablated volume per pulse within the burst was calculated either from the ablated volume per burst or from the ablation depth of the quadratic cavities. With the second to fourth pulses in the bursts, a reduction of the ablated volume per pulse in comparison with the first pulse in the bursts (i.e., to the use of single pulses) was found for both single- and multiburst ablation, which is assumed to be due to plasma shielding. By contrast, the ablated volume per pulse within the bursts increases for the fifth to eighth pulses. Heat accumulation effect and the influence of the heated plasma can be assumed to be the reason for these higher ablation rates. SEM micrographs also show that there is a higher melt ejection out of the laser processed area. This is indicated by the formation of bulges about the ablated area.

  16. Emission Spectroscopic Boundary Layer Investigation during Ablative Material Testing in Plasmatron.

    Helber, Bernd; Chazot, Olivier; Hubin, Annick; Magin, Thierry E

    2016-06-09

    Ablative Thermal Protection Systems (TPS) allowed the first humans to safely return to Earth from the moon and are still considered as the only solution for future high-speed reentry missions. But despite the advancements made since Apollo, heat flux prediction remains an imperfect science and engineers resort to safety factors to determine the TPS thickness. This goes at the expense of embarked payload, hampering, for example, sample return missions. Ground testing in plasma wind-tunnels is currently the only affordable possibility for both material qualification and validation of material response codes. The subsonic 1.2MW Inductively Coupled Plasmatron facility at the von Karman Institute for Fluid Dynamics is able to reproduce a wide range of reentry environments. This protocol describes a procedure for the study of the gas/surface interaction on ablative materials in high enthalpy flows and presents sample results of a non-pyrolyzing, ablating carbon fiber precursor. With this publication, the authors envisage the definition of a standard procedure, facilitating comparison with other laboratories and contributing to ongoing efforts to improve heat shield reliability and reduce design uncertainties. The described core techniques are non-intrusive methods to track the material recession with a high-speed camera along with the chemistry in the reactive boundary layer, probed by emission spectroscopy. Although optical emission spectroscopy is limited to line-of-sight measurements and is further constrained to electronically excited atoms and molecules, its simplicity and broad applicability still make it the technique of choice for analysis of the reactive boundary layer. Recession of the ablating sample further requires that the distance of the measurement location with respect to the surface is known at all times during the experiment. Calibration of the optical system of the applied three spectrometers allowed quantitative comparison. At the fiber scale

  17. Emission Spectroscopic Boundary Layer Investigation during Ablative Material Testing in Plasmatron

    Helber, Bernd; Chazot, Olivier; Hubin, Annick; Magin, Thierry E.

    2016-01-01

    Ablative Thermal Protection Systems (TPS) allowed the first humans to safely return to Earth from the moon and are still considered as the only solution for future high-speed reentry missions. But despite the advancements made since Apollo, heat flux prediction remains an imperfect science and engineers resort to safety factors to determine the TPS thickness. This goes at the expense of embarked payload, hampering, for example, sample return missions. Ground testing in plasma wind-tunnels is currently the only affordable possibility for both material qualification and validation of material response codes. The subsonic 1.2MW Inductively Coupled Plasmatron facility at the von Karman Institute for Fluid Dynamics is able to reproduce a wide range of reentry environments. This protocol describes a procedure for the study of the gas/surface interaction on ablative materials in high enthalpy flows and presents sample results of a non-pyrolyzing, ablating carbon fiber precursor. With this publication, the authors envisage the definition of a standard procedure, facilitating comparison with other laboratories and contributing to ongoing efforts to improve heat shield reliability and reduce design uncertainties. The described core techniques are non-intrusive methods to track the material recession with a high-speed camera along with the chemistry in the reactive boundary layer, probed by emission spectroscopy. Although optical emission spectroscopy is limited to line-of-sight measurements and is further constrained to electronically excited atoms and molecules, its simplicity and broad applicability still make it the technique of choice for analysis of the reactive boundary layer. Recession of the ablating sample further requires that the distance of the measurement location with respect to the surface is known at all times during the experiment. Calibration of the optical system of the applied three spectrometers allowed quantitative comparison. At the fiber scale

  18. US-Guided Femoral and Sciatic Nerve Blocks for Analgesia During Endovenous Laser Ablation

    Yilmaz, Saim, E-mail: ysaim@akdeniz.edu.tr; Ceken, Kagan; Alimoglu, Emel; Sindel, Timur [Akdeniz University School of Medicine, Department of Radiology (Turkey)

    2013-02-15

    Endovenous laser ablation may be associated with significant pain when performed under standard local tumescent anesthesia. The purpose of this study was to investigate the efficacy of femoral and sciatic nerve blocks for analgesia during endovenous ablation in patients with lower extremity venous insufficiency. During a 28-month period, ultrasound-guided femoral or sciatic nerve blocks were performed to provide analgesia during endovenous laser ablation in 506 legs and 307 patients. The femoral block (n = 402) was performed at the level of the inguinal ligament, and the sciatic block at the posterior midthigh (n = 124), by injecting a diluted lidocaine solution under ultrasound guidance. After the blocks, endovenous laser ablations and other treatments (phlebectomy or foam sclerotherapy) were performed in the standard fashion. After the procedures, a visual analogue pain scale (1-10) was used for pain assessment. After the blocks, pain scores were 0 or 1 (no pain) in 240 legs, 2 or 3 (uncomfortable) in 225 legs, and 4 or 5 (annoying) in 41 legs. Patients never experienced any pain higher than score 5. The statistical analysis revealed no significant difference between the pain scores of the right leg versus the left leg (p = 0.321) and between the pain scores after the femoral versus sciatic block (p = 0.7). Ultrasound-guided femoral and sciatic nerve blocks may provide considerable reduction of pain during endovenous laser and other treatments, such as ambulatory phlebectomy and foam sclerotherapy. They may make these procedures more comfortable for the patient and easier for the operator.

  19. 3D Multifunctional Ablative Thermal Protection System

    Feldman, Jay; Venkatapathy, Ethiraj; Wilkinson, Curt; Mercer, Ken

    2015-01-01

    NASA is developing the Orion spacecraft to carry astronauts farther into the solar system than ever before, with human exploration of Mars as its ultimate goal. One of the technologies required to enable this advanced, Apollo-shaped capsule is a 3-dimensional quartz fiber composite for the vehicle's compression pad. During its mission, the compression pad serves first as a structural component and later as an ablative heat shield, partially consumed on Earth re-entry. This presentation will summarize the development of a new 3D quartz cyanate ester composite material, 3-Dimensional Multifunctional Ablative Thermal Protection System (3D-MAT), designed to meet the mission requirements for the Orion compression pad. Manufacturing development, aerothermal (arc-jet) testing, structural performance, and the overall status of material development for the 2018 EM-1 flight test will be discussed.

  20. Design calculations for NIF convergent ablator experiments

    Olson R.E.

    2013-11-01

    Full Text Available The NIF convergent ablation tuning effort is underway. In the early experiments, we have discovered that the design code simulations over-predict the capsule implosion velocity and shock flash ρr, but under-predict the hohlraum x-ray flux measurements. The apparent inconsistency between the x-ray flux and radiography data implies that there are important unexplained aspects of the hohlraum and/or capsule behavior.

  1. Radiofrequency ablation of two femoral head chondroblastomas

    Petsas, Theodore [Department of Radiology, University of Patras (Greece); Megas, Panagiotis [Department of Orthopaedic Surgery, University of Patras (Greece)]. E-mail: panmegas@med.upatras.gr; Papathanassiou, Zafiria [Department of Radiology, University of Patras (Greece)

    2007-07-15

    Chondroblastoma is a rare benign cartilaginous bone tumor. Surgical resection is the treatment of choice for pain relief and prevention of further growth. Open surgical techniques are associated with complications, particularly when the tumors are located in deep anatomical sites. The authors performed RF ablation in two cases of subarticular femoral head chondroblastomas and emphasize its positive impact. The clinical course, the radiological findings and the post treatment results are discussed.

  2. Radiofrequency ablation of small liver malignancies under magnetic resonance guidance: progress in targeting and preliminary observations with temperature monitoring

    Terraz, Sylvain; Cernicanu, Alexandru; Lepetit-Coiffe, Matthieu; Viallon, Magalie; Salomir, Rares; Becker, Christoph D. [University Hospitals of Geneva, Department of Radiology, Geneva 14 (Switzerland); Mentha, Gilles [University Hospitals of Geneva, Department of Visceral Surgery and Transplantation, Geneva (Switzerland)

    2010-04-15

    To evaluate the feasibility and effectiveness of magnetic resonance (MR)-guided radiofrequency (RF) ablation for small liver tumours with poor conspicuity on both contrast-enhanced ultrasonography (US) and computed tomography (CT), using fast navigation and temperature monitoring. Sixteen malignant liver nodules (long-axis diameter, 0.6-2.4 cm) were treated with multipolar RF ablation on a 1.5-T wide-bore MR system in ten patients. Targeting was performed interactively, using a fast steady-state free precession sequence. Real-time MR-based temperature mapping was performed, using gradient echo-echo planar imaging (GRE-EPI) and hardware filtering. MR-specific treatment data were recorded. The mean follow-up time was 19 {+-} 7 months. Correct placement of RF electrodes was obtained in all procedures (image update, <500 ms; mean targeting time, 21 {+-} 11 min). MR thermometry was available for 14 of 16 nodules (88%) with an accuracy of 1.6 C in a non-heated region. No correlation was found between the size of the lethal thermal dose and the ablation zone at follow-up imaging. The primary and secondary effectiveness rates were 100% and 91%, respectively. RF ablation of small liver tumours can be planned, targeted, monitored and controlled with MR imaging within acceptable procedure times. Temperature mapping is technically feasible, but the clinical benefit remains to be proven. (orig.)

  3. Long-term Results after CT-Guided Percutaneous Ethanol Ablation for the Treatment of Hyperfunctioning Adrenal Disorders

    Nathan Elie Frenk

    Full Text Available OBJECTIVES: To evaluate the safety and long-term efficacy of computed tomography-guided percutaneous ethanol ablation for benign primary and secondary hyperfunctioning adrenal disorders. METHOD: We retrospectively evaluated the long-term results of nine patients treated with computed tomography-guided percutaneous ethanol ablation: eight subjects who presented with primary adrenal disorders, such as pheochromocytoma, primary macronodular adrenal hyperplasia and aldosterone-producing adenoma, and one subject with Cushing disease refractory to conventional treatment. Eleven sessions were performed for the nine patients. The patient data were reviewed for the clinical outcome and procedure-related complications over ten years. RESULTS: Patients with aldosterone-producing adenoma had clinical improvement: symptoms recurred in one case 96 months after ethanol ablation, and the other patient was still in remission 110 months later. All patients with pheochromocytoma had clinical improvement but were eventually submitted to surgery for complete remission. No significant clinical improvement was seen in patients with hypercortisolism due to primary macronodular adrenal hyperplasia or Cushing disease. Major complications were seen in five of the eleven procedures and included cardiovascular instability and myocardial infarction. Minor complications attributed to sedation were seen in two patients. CONCLUSION: Computed tomography-guided ethanol ablation does not appear to be suitable for the long-term treatment of hyperfunctioning adrenal disorders and is not without risks.

  4. Radiative Ablation of Disks Around Massive Stars

    Kee, N D

    2015-01-01

    Hot, massive stars (spectral types O and B) have extreme luminosities ($10^4 -10^6 L_\\odot$) that drive strong stellar winds through UV line-scattering. Some massive stars also have disks, formed by either decretion from the star (as in the rapidly rotating "Classical Be stars"), or accretion during the star's formation. This dissertation examines the role of stellar radiation in driving (ablating) material away from these circumstellar disks. A key result is that the observed month to year decay of Classical Be disks can be explained by line-driven ablation without, as previously done, appealing to anomalously strong viscous diffusion. Moreover, the higher luminosity of O stars leads to ablation of optically thin disks on dynamical timescales of order a day, providing a natural explanation for the lack of observed Oe stars. In addition to the destruction of Be disks, this dissertation also introduces a model for their formation by coupling observationally inferred non-radial pulsation modes and rapid stellar...

  5. Ultraviolet laser ablation of polyimide films

    Srinivasan, R.; Braren, B.; Dreyfus, R. W.

    1987-01-01

    Pulsed laser radiation at 193, 248, or 308 nm can etch films of polyimide (DuPont KaptonTM). The mechanism of this process has been examined by the chemical analysis of the condensible products, by laser-induced fluorescence analysis of the diatomic products, and by the measurement of the etch depth per pulse over a range of fluences of the laser pulse. The most important product as well as the only one condensible at room temperature is carbon. Laser-induced fluorescence analysis showed that C2 and CN were present in the ablation plume. At 248 nm, even well below the fluence threshold of 0.08 J/cm2 for significant ablation, these diatomic species are readily detected and are measured to leave the polymer surface with translational energy of ˜5 eV. These results, when combined with the photoacoustic studies of Dyer and Srinivasan [Appl. Phys. Lett. 48, 445 (1986)], show that a simple photochemical mechanism in which one photon or less (on average) is absorbed per monomer is inadequate. The ablation process must involve many photons per monomer unit to account for the production of predominantly small (<4 atoms) products and the ejection of these fragments at supersonic velocities.

  6. Laser ablation cell sorting in scanning cytometry

    Shen, Feimo; Price, Jeffrey H.

    2001-05-01

    Flow cytometry has been an important tool for automated cells sorting. However, the lack of good sensitivity prevents it from being used for rare events sorting; furthermore, fragile cells, anchorage-dependent cells, and clump forming cells cannot be sorted this way. A fully automated, high-speed scanning cytometer with autofocus and image segmentation is capable of accurately locating contaminant cells in a monolayer cell population. A laser ablation system was incorporated into the cytometer to negatively sort out the unwanted cells by applying a focused, ultra-short laser pulse (sub-micron diameter, pulse duration = 4 nsec, wavelength - 500 nm) to each targeted cell. Due to the high power density (approximately 1010 W/cm2) that was present at the focal point, disruptive mechanical forces were generated and were responsible for the kill. Fluorescently stained NIH-3T3 fibroblast cells were used as a model contaminant target ells in an unstained NIH-3T3 population to determine the identification-kill effectiveness. The contaminant cells were stained with the fluorochrome CellTracker Blue CMAC, whereas the background cells were left intact. Ablation pulses were applied in frame-by-frame increment batches to the cell culture on the microscope. The negative sorting effectiveness was analyzed by automatically re-scanning the post-ablation cell culture in phase contrast and propidium iodide stained epi fluorescent fields to verify cell death.

  7. Microwave soft tissue ablation (Invited Paper)

    Clegg, Peter J.; Cronin, Nigel J.

    2005-04-01

    Microsulis, in conjunction with the University of Bath have developed a set of novel microwave applicators for the ablation of soft tissues. These interstitial applicators have been designed for use in open surgical, laparoscopic and percutaneous settings and range in diameter from 2.4 to 7 mm. A 20 mm diameter flat faced interface applicator was developed as an adjunct to the open surgical interstitial applicator and has been applied to the treatment of surface breaking lesions in hepatobiliary surgery. Taken as a complete tool set the applicators are capable of treating a wide range of conditions in a safe and efficacious manner. The modality employs a radiated electromagnetic field at the allocated medical frequency of 2.45 GHz and powers between 30 and 150 Watts. Computer simulations, bench testing, safety and efficacy testing, ex-vivo and in-vivo work plus clinical trials have demonstrated that these systems are capable of generating large volumes of ablation in short times with favourable ablation geometries. Clinical studies have shown very low complication rates with minimal local recurrence. It is considered that this modality offers major advantages over currently marketed products. The technique is considered to be particularly safe as it is quick and there is no passage of current obviating the requirement for grounding pads. Since the microwave field operates primarily on water and all soft tissues with the exception of fat are made up of approximately 70% water the heating pattern is highly predictable making repeatability a key factor for this modality.

  8. Reduction of radiation exposure in catheter ablation of atrial fibrillation: Lesson learned

    Roberto; De; Ponti

    2015-01-01

    Over the last decades, the concern for the radiation injury hazard to the patients and the professional staff has increased in the medical community. Since there is no magnitude of radiation exposure that is known to be completely safe, the use of ionizing radiation during medical diagnostic or interventional procedures should be as low as reasonably achievable(ALARA principle). Nevertheless, in cardiovascular medicine, radiation exposure for coronary percutaneous interventions or catheter ablation of cardiac arrhythmias may be high: for ablation of a complex arrhythmia, such as atrial fibrillation, the mean dose can be > 15 m Sv and in some cases > 50 m Sv. In interventional electrophysiology, although fluoroscopy has been widely used since the beginning to navigate catheters in the heart and the vessels and to monitor their position, the procedure is not based on fluoroscopic imaging. Therefore, nonfluoroscopic three-dimensional systems can be used to navigate electrophysiology catheters in the heart with no or minimal use of fluoroscopy. Although zerofluoroscopy procedures are feasible in limited series, there may be difficulties in using no fluoroscopy on a routine basis. Currently, a significant reduction in radiation exposure towards near zero-fluoroscopy procedures seems a simpler task to achieve, especially in ablation of complex arrhythmias, such as atrial fibrillation. The data reported in the literature suggest the following three considerations. First, the use of the non-fluoroscopic systems is associated with a consistent reduction in radiation exposure in multiple centers: the more sophisticated and reliable this technology is, the higher the reduction in radiation exposure. Second, the use of these systems does not automatically lead to reduction of radiation exposure, but an optimized workflow should be developed and adopted for a safe non-fluoroscopic navigation of catheters. Third, at any level of expertise, there is a specific learning curve for

  9. Inducible forebrain-specific ablation of the transcription factor Creb during adulthood induces anxiety but no spatial/contextual learning deficits

    Miriam Annika Vogt

    2014-11-01

    Full Text Available The cyclic AMP (cAMP-response element binding protein (CREB is an activity-dependent transcription factor playing a role in synaptic plasticity, learning and memory, and emotional behavior. However, the impact of Creb ablation on rodent behavior is vague as e.g. memory performance of different Creb mutant mice depends on the specific type of mutation per se but additionally on the background and learning protocol differences. Here we present the first targeted ablation of CREB induced during adulthood selectively in principal forebrain neurons in a pure background strain of C57BL/6 mice. All hippocampal principal neurons exhibited lack of CREB expression. Mutant mice showed a severe anxiety phenotype in the openfield and novel object exploration test as well as in the Dark-Light Box Test, but unaltered hippocampus-dependent long-term memory in the Morris water maze and in context dependent fear conditioning. On the molecular level, CREB ablation led to CREM up regulation in the hippocampus and frontal cortex which may at least in part compensate for the loss of CREB. BDNF, a postulated CREB target gene, was down regulated in the frontal lobe but not in the hippocampus; neurogenesis remained unaltered. Our data indicate that in the adult mouse forebrain the late onset of CREB ablation can, in case of memory functionality, be compensated for and is not essential for memory consolidation and retrieval during adulthood. In contrast, the presence of CREB protein during adulthood seems to be pivotal for the regulation of emotional behavior.

  10. Transient Newton rings in dielectrics upon fs laser ablation

    Garcia-Lechuga, Mario; Hernandez-Rueda, Javier; Solis, Javier

    2014-01-01

    We report the appearance of transient Newton rings in dielectrics (sapphire and lead-oxide glass) during ablation with single fs laser pulses. Employing femtosecond microscopy with 800 nm excitation and 400 nm illumination, we observe a characteristic ring pattern that dynamically changes for increasing delay times between pump and probe pulse. Such transient Newton rings have been previously observed in metals and semiconductors at fluences above the ablation threshold and were related to optical interference of the probe beam reflected at the front surface of the ablating layer and at the interface of the non-ablating substrate. Yet, it had been generally assumed that this phenomenon cannot be (and has not been) observed in dielectrics due to the different ablation mechanism and optical properties of dielectrics. The fact that we are able to observe them has important consequences for the comprehension of the ablation mechanisms in dielectrics and provides a new method for investigating these mechanisms in ...

  11. Ablation Performance of a Novel Super-hybrid Composite

    Jun QIU; Xiaoming CAO; Chong TIAN; Jinsong ZHANG

    2005-01-01

    A novel super-hybrid composite (NSHC) was boron-modified phenolic resin (BPR) with three-dimensional reticulated SiC ceramic (3DRC) and high silica fibers. Ablation performance of the NSHC was studied. The results show that the linear ablation rate of NSHC was lower than that of pure BPR and the high silica/BPR composite. Its linear ablation rate is 1/17 of the high silica/BPR. Mass ablation rate of the NSHC is very close to that of the pure BPR and the high silica/BPR composite. Scanning electron microscope (SEM) analysis indicates that 3DRC has scarcely changed its shape at the ablation temperature. Its special reticulated structure can restrict the materials deformation and prevent high velocity heat flow from eroding the surface of the materials largely and thus increase ablation resistance of the NSHC.

  12. Looking ahead? Computerized maze task performance by chimpanzees (Pan troglodytes), rhesus monkeys (Macaca mulatta), capuchin monkeys (Cebus apella), and human children (Homo sapiens).

    Beran, Michael J; Parrish, Audrey E; Futch, Sara E; Evans, Theodore A; Perdue, Bonnie M

    2015-05-01

    Human and nonhuman primates are not mentally constrained to the present. They can remember the past and-at least to an extent-anticipate the future. Anticipation of the future ranges from long-term prospection such as planning for retirement to more short-term future-oriented cognition such as planning a route through a maze. Here we tested a great ape species (chimpanzees), an Old World monkey species (rhesus macaques), a New World monkey species (capuchin monkeys), and human children on a computerized maze task. All subjects had to move a cursor through a maze to reach a goal at the bottom of the screen. For best performance on the task, subjects had to "plan ahead" to the end of the maze to move the cursor in the correct direction, avoid traps, and reverse directions if necessary. Mazes varied in difficulty. Chimpanzees were better than both monkey species, and monkeys showed a particular deficit when moving away from the goal or changing directions was required. Children showed a similar pattern to monkeys regarding the effects of reversals and moves away from the goal, but their overall performance in terms of correct maze completion was similar to the chimpanzees. The results highlight similarities as well as differences in planning across species and the role that inhibitory control may play in future-oriented cognition in primates.

  13. CT-guided radiofrequency ablation of spinal osteoid osteomas with concomitant perineural and epidural irrigation for neuroprotection

    Klass, Darren [Norfolk and Norwich University Hospital, Department of Radiology, Norwich (United Kingdom); Norfolk and Norwich University Hospital, Radiology Academy, Cotman Centre, Norwich (United Kingdom); Marshall, Tom; Toms, Andoni [Norfolk and Norwich University Hospital, Department of Radiology, Norwich (United Kingdom)

    2009-09-15

    Here we report our experience of a neuroprotective adaptation of the technique of CT-guided radiofrequency (RF) ablation of spinal osteoid osteomas. Over 9 years seven patients underwent eight CT-guided RF treatments for osteoid osteoma. CT-guided RF ablation was performed with general anaesthesia. The lesion was heated to 90 C for 2 min for two cycles by using a Cosman SMK TC-10 RF electrode. This was preceded by a bolus of room temperature sterile water (10 ml) injected through a 26G curved spinal needle into the exit foramen and adjacent epidural space for neuroprotection. The age of the patient, sex, lesion location, biopsy results and complications were recorded. All the biopsies (n = 7) demonstrated histological features of osteoid osteoma. All the procedures were technically successful. Clinical success was assessed up to 3 years post procedure. There was an 85% clinical success rate (6 of the 7 patients), with recurrence of a lesion at 6 months, necessitating a repeat procedure (successful). CT-guided percutaneous RF ablation of spinal osteoid osteoma preceded by bolus of sterile water, injected through a spinal needle into the exit foramen and adjacent epidural space for neuroprotection, is a safe and effective procedure. (orig.)

  14. Assessing Temperature-Controlled Radiofrequency Tonsil Ablation for Treatment of Halitosis Caused by Chronic Tonsillitis with Caseum

    F. Hashemian

    2015-10-01

    Full Text Available Introduction & Objective: Chronic tonsillitis with caseum has been proven to be the cause of halitosis. The objective of this study was to evaluate the efficacy and safety of temperature-controlled radiofrequency tonsil ablation in the treatment of halitosis caused by chronic tonsil-litis with caseum. Materials & Methods: In this clinical trial study 28 adult patients with halitosis due to chronic tonsillitis with caseum were treated by temperature-controlled radiofrequency tonsil ablation and efficacy and complications of procedure were recorded and the data were analyzed by Spss software and paired t-test. Results: The difference between the amount of halitosis was statistically significant before and after the procedure (P <0.001. Patients’ pain were mild to moderate .Mild bleeding occurred in 21% of patients and 79% had no bleeding. In average 3.14 days after the procedure patients tolerated regular diet and after 1.96 days they could do their daily routines. Conclusion: Temperature-controlled radiofrequency tonsil ablation is a safe and effective method for treatment of halitosis due to chronic tonsillitis with caseum and have several ad-vantages compared to conventional tonsillectomy such as reduced post-operative pain and bleeding, shorter recovery time and convenience of an office procedure. (Sci J Hamadan Univ Med Sci 2015; 22 (3: 179-186

  15. [Moist ablation of the corneal surface with the Er:YAG laser. Results of optimizing ablation].

    Bende, T; Jean, B; Matallana, M; Seiler, T; Steiner, R

    1994-10-01

    The Er:YAG laser, emitting light at 2.94 microns, may be an alternative to the 193 nm excimer laser for photorefractive keratectomy. Compared to the excimer laser, the ablation rate is very high. Surface roughness is also more pronounced than for the excimer laser. Using a precorneal liquid film, these two factors can be reduced, as shown in ablation experiments performed on porcine corneas. Thermal damage of the remaining corneal tissue is another side effect. There is no significant decrease in the amount of thermal damage with this new technique,--not even when the pulse length is reduced.

  16. MR guided percutaneous laser lumbar disk hernia ablation

    Hashimoto, Takuo; Terao, Tohru; Ishibashi, Toshihiro; Yuhki, Ichiro; Harada, Junta; Tashima, Michiko [Jikei Univ., Chiba (Japan). Kashiwa Hospital; Abe, Toshiaki

    1998-03-01

    An MRI unit for interventional procedure is very useful for minimally invasive surgery of the brain and spine. Percutaneous laser disc decompression (PLDD) utilizing X-ray fluoroscopy is a relatively new less invasive procedure for treatment of lumbar disc herniation. MR guided laser surgery is applied to patients with disc herniation at our department. Approaching the target of the disc protrusion was easily conducted and vaporizing the disc hernia directly using a laser was possible under MR fluoroscopy. The purpose of the present study is to evaluate the usefulness of MR guided percutaneous laser disc hernia ablation (MR-guided PLDHA). As subjects, 36 patients with lumbar disc herniation, including 23 cases with L4/5 involvement and 13 cases with L5/S1 involvement were studied. Among these, 26 were males and 10 were females, age ranging from 24 to 62. We used an open type MR system (Hitachi, Airis 0.3T), a permanent, open configuration MR system. A YAG laser (LaserScope, USA) was used for PLDHA. An MR compatible 18G titanium needle 15 cm in length was used to puncture the herniated discs. The MR compatible needle was clearly visualized, and used to safely and accurately puncture the target herniated disc in each case with multidimensional guidance. Application of the laser was performed with MR guidance. The energy dose from the laser ranged from 800 to 2100 joules. In most cases, signs and symptoms improved in the patients immediately after disc vaporization. The overall success rate was 88.9%. The complication rate was 2.8%, including one case of discitis after PLDHA. MR fluoroscopy sequence permits near real time imaging and provides an easy approach to the therapeutic target of disc herniation. MR guided PLDHA is a minimally invasive procedure and is very useful for the treatment of lumbar disc protrusion. (author)

  17. Numerical simulation of copper ablation by ultrashort laser pulses

    Ding, PengJi; Li, YuHong

    2011-01-01

    Using a modified self-consistent one-dimensional hydrodynamic lagrangian fluid code, laser ablation of solid copper by ultrashort laser pulses in vacuum was simulated to study fundamental mechanisms and to provide a guide for drilling periodic microholes or microgratings on the metal surface. The simulated laser ablation threshold is a approximate constancy in femtosecond regime and increases as the square root of pulse duration in picosecond regime. The ablation depth as a function of pulse duration shows four different regimes and a minimum for a pulse duration of ~ 12ps for various laser fluences. The influence of laser-induced plasma shielding on ablation depth is also studied.

  18. Effects of laser ablation on cemented tungsten carbide surface quality

    Tan, J.L.; Butler, D.L.; Sim, L.M.; Jarfors, A.E.W. [Singapore Institute of Manufacturing Technology, Singapore (Singapore)

    2010-11-15

    Although laser micromachining has been touted as being the most promising way to fabricate micro tools, there has been no proper evaluation of the effects of laser ablation on bulk material properties. The current work demonstrates the effects of laser ablation on the properties of a cemented tungsten carbide surface. Of particular interest is the resultant increase in compressive residual stresses in the ablated surface. From this study it is seen that there are no adverse effects from laser ablation of cemented tungsten carbide that would preclude its use for the fabrication of micro-tools but a finishing process may not be avoidable. (orig.)

  19. Effects of laser ablation on cemented tungsten carbide surface quality

    Tan, J. L.; Butler, D. L.; Sim, L. M.; Jarfors, A. E. W.

    2010-11-01

    Although laser micromachining has been touted as being the most promising way to fabricate micro tools, there has been no proper evaluation of the effects of laser ablation on bulk material properties. The current work demonstrates the effects of laser ablation on the properties of a cemented tungsten carbide surface. Of particular interest is the resultant increase in compressive residual stresses in the ablated surface. From this study it is seen that there are no adverse effects from laser ablation of cemented tungsten carbide that would preclude its use for the fabrication of micro-tools but a finishing process may not be avoidable.

  20. Thermal character in organic polymers with nanojoule femtosecond laser ablation

    Xiaochang Ni(倪晓昌); Ching-Yue Wang(王清月); Yanfeng Li(栗岩峰); Minglie Hu(胡明列); Zhuan Wang(王专); Lu Chai(柴路)

    2003-01-01

    Ablation experiments with femtosecond (fs) laser pulse (pulse duration 37 fs, wavelength 800 nm) on organic polymers have been performed in air. The ablation threshold is found to be only several nanojoules. The diameters of the dots ablated in the organic polymers are influenced by the laser fluence and the number of laser pulses. It is observed that heat is diffused in a threadlike manner in all directions around the central focus region. Explanations of the observed phenomena are presented. A one-dimensional waveguide is also ablated in the organic polymers.