Multiple sclerosis(MS) is characterized by chronic inflammation in conjunction with neurodegeneration within the central nervous system. Most individuals with MS begin with a relapsing remitting course that later tr...Multiple sclerosis(MS) is characterized by chronic inflammation in conjunction with neurodegeneration within the central nervous system. Most individuals with MS begin with a relapsing remitting course that later transitions to secondary progressive MS. Currently available disease-modifying therapies(DMTs) for relapsing MS have been demonstrated to reduce disease activity, however most patients require a change in therapy over the course of their disease. Treatment goals include the prevention of relapses and disability accumulation and to achieve this objective requires careful planning. Sequencing of DMTs for individual patients should be designed in such a way to maximize disease control and minimize risk based on the mechanism of action, pharmacokinetic and pharmacodynamic properties of each therapy. This includes the DMT patients are being switched from to those they are being switched to. The reversibility of immune system effects should be a key consideration for DMT sequence selection. This feature varies across DMTs and should factor more prominently in decision making as newer treatments become available for the prevention of disability accumulation in patients with progressive MS. In this short review, we discuss the landscape of existing therapies with an eye to the future when planning for optimal DMT sequencing. While no cure exists for MS, efforts are being directed toward research in neuroregeneration with the hope for positive outcomes.展开更多
OBJECTIVES: This study was designed to assess the impact of prevention of bradycardia with physiologic pacing on the severity of obstructive sleep apnea. BACKGROUND: Apneic episodes during sleep are associated with sl...OBJECTIVES: This study was designed to assess the impact of prevention of bradycardia with physiologic pacing on the severity of obstructive sleep apnea. BACKGROUND: Apneic episodes during sleep are associated with slowing of the heart rate during apnea and tachycardia with subsequent arousal. Patients with permanent pacemakers may have reduced episodes of sleep apnea when their pacemaker rate is set faster than their spontaneous nocturnal heart rate. METHODS: We conducted a prospective, randomized, single-blind crossover trial of temporary atrial pacing in obstructive sleep apnea to reduce the apnea hypopnea index(AHI). Fifteen patients(age 60± 13 years, 12 men) with moderate to severe obstructive sleep apnea(AHI 34± 14) underwent insertion of an externalized atrial permanent pacing system via the left subclavian vein. Patients underwent overnight respiratory sleep studies in hospital, during atrial pacing at 75 beats/min, and with pacing turned off. The order of pacing mode was randomized, with crossover the subsequent night to the other mode. Patients were blinded to pacing mode, and the analysis of sleep recordings was blind to pacing mode. RESULTS: Pacing was tolerated without complications in all patients. Overnight physiologic pacing did not affect the AHI(pacing 39± 21/h vs. control 42± 21/h, p=0.23, 95% confidence interval- 9.3 to 2.5 for difference), desaturation time(pacing 3.8± 6.0% vs. control 3.5± 4.3% , p=0.70), or the minimum SaO2(pacing 75± 10% vs. control 77± 11% , p=0.38). There was a borderline significant reduction in circulatory time with pacing(pacing 23.4± 3.2 s vs. control 25.5± 4.4 s, p=0.09). CONCLUSIONS: Temporary atrial pacing does not appear to improve respiratory manifestations of obstructive sleep apnea. Permanent atrial pacing in this patient population does not appear to be justified.展开更多
Background and Purpose - The length of stay (LOS) is the main cost- determining factor for inpatients with acute stroke. Although studies have identified variables associated with LOS, few have analyzed predictors of ...Background and Purpose - The length of stay (LOS) is the main cost- determining factor for inpatients with acute stroke. Although studies have identified variables associated with LOS, few have analyzed predictors of longer stay after receiving thrombolytic therapy for acute stroke. Methods - We studied all consecutive acute stroke patients receiving intravenous recombinant tissue plasminogen activator (rtPA) admitted to the London Health Sciences Center, in London, Ontario, Canada, from 1999 to 2003. Longer stay was defined as LOS ≥ 7days after admission. Demographic as well as baseline clinical, laboratory, and imaging variables were analyzed to identify predictors of LOS. Significant variables were entered into a multivariate logistic regression analysis. Results - Among 216 acute stroke patients receiving rtPA, the median LOS was 6 days. LOS was >7 days in 102 (49% ) patients. Age ≥ 70 (odds ratio [OR], 2.2; 95% CI, 1.2 to 4.0), lack of improvement at 24 hours (OR, 2.5; 95% CI, 1.4 to 4.4), prestroke modified Rankin Scale ≥ 2 (OR, 2.4; 95% CI, 1.2 to 4.9), baseline National Institutes of Health Stroke Scale score ≥ 15 (OR, 9.4; 95% CI, 3.2 to 27.6), cortical involvement (OR, 2.2; 95% CI, 1.2 to 3.9), and new infarction on the control computed tomography (CT; OR, 2.8; 95% CI, 1.4 to 5.9) were independent predictors of longer stay. Conclusions - Lack of improvement at 24 hours after rtPA, cortical involvement, and new infarction on the 24- hour CT scan are relevant variables that can independently affect the LOS. These new variables may be useful for establishing policy in relation to the organization and planning of the health care system.展开更多
文摘Multiple sclerosis(MS) is characterized by chronic inflammation in conjunction with neurodegeneration within the central nervous system. Most individuals with MS begin with a relapsing remitting course that later transitions to secondary progressive MS. Currently available disease-modifying therapies(DMTs) for relapsing MS have been demonstrated to reduce disease activity, however most patients require a change in therapy over the course of their disease. Treatment goals include the prevention of relapses and disability accumulation and to achieve this objective requires careful planning. Sequencing of DMTs for individual patients should be designed in such a way to maximize disease control and minimize risk based on the mechanism of action, pharmacokinetic and pharmacodynamic properties of each therapy. This includes the DMT patients are being switched from to those they are being switched to. The reversibility of immune system effects should be a key consideration for DMT sequence selection. This feature varies across DMTs and should factor more prominently in decision making as newer treatments become available for the prevention of disability accumulation in patients with progressive MS. In this short review, we discuss the landscape of existing therapies with an eye to the future when planning for optimal DMT sequencing. While no cure exists for MS, efforts are being directed toward research in neuroregeneration with the hope for positive outcomes.
文摘OBJECTIVES: This study was designed to assess the impact of prevention of bradycardia with physiologic pacing on the severity of obstructive sleep apnea. BACKGROUND: Apneic episodes during sleep are associated with slowing of the heart rate during apnea and tachycardia with subsequent arousal. Patients with permanent pacemakers may have reduced episodes of sleep apnea when their pacemaker rate is set faster than their spontaneous nocturnal heart rate. METHODS: We conducted a prospective, randomized, single-blind crossover trial of temporary atrial pacing in obstructive sleep apnea to reduce the apnea hypopnea index(AHI). Fifteen patients(age 60± 13 years, 12 men) with moderate to severe obstructive sleep apnea(AHI 34± 14) underwent insertion of an externalized atrial permanent pacing system via the left subclavian vein. Patients underwent overnight respiratory sleep studies in hospital, during atrial pacing at 75 beats/min, and with pacing turned off. The order of pacing mode was randomized, with crossover the subsequent night to the other mode. Patients were blinded to pacing mode, and the analysis of sleep recordings was blind to pacing mode. RESULTS: Pacing was tolerated without complications in all patients. Overnight physiologic pacing did not affect the AHI(pacing 39± 21/h vs. control 42± 21/h, p=0.23, 95% confidence interval- 9.3 to 2.5 for difference), desaturation time(pacing 3.8± 6.0% vs. control 3.5± 4.3% , p=0.70), or the minimum SaO2(pacing 75± 10% vs. control 77± 11% , p=0.38). There was a borderline significant reduction in circulatory time with pacing(pacing 23.4± 3.2 s vs. control 25.5± 4.4 s, p=0.09). CONCLUSIONS: Temporary atrial pacing does not appear to improve respiratory manifestations of obstructive sleep apnea. Permanent atrial pacing in this patient population does not appear to be justified.
文摘Background and Purpose - The length of stay (LOS) is the main cost- determining factor for inpatients with acute stroke. Although studies have identified variables associated with LOS, few have analyzed predictors of longer stay after receiving thrombolytic therapy for acute stroke. Methods - We studied all consecutive acute stroke patients receiving intravenous recombinant tissue plasminogen activator (rtPA) admitted to the London Health Sciences Center, in London, Ontario, Canada, from 1999 to 2003. Longer stay was defined as LOS ≥ 7days after admission. Demographic as well as baseline clinical, laboratory, and imaging variables were analyzed to identify predictors of LOS. Significant variables were entered into a multivariate logistic regression analysis. Results - Among 216 acute stroke patients receiving rtPA, the median LOS was 6 days. LOS was >7 days in 102 (49% ) patients. Age ≥ 70 (odds ratio [OR], 2.2; 95% CI, 1.2 to 4.0), lack of improvement at 24 hours (OR, 2.5; 95% CI, 1.4 to 4.4), prestroke modified Rankin Scale ≥ 2 (OR, 2.4; 95% CI, 1.2 to 4.9), baseline National Institutes of Health Stroke Scale score ≥ 15 (OR, 9.4; 95% CI, 3.2 to 27.6), cortical involvement (OR, 2.2; 95% CI, 1.2 to 3.9), and new infarction on the control computed tomography (CT; OR, 2.8; 95% CI, 1.4 to 5.9) were independent predictors of longer stay. Conclusions - Lack of improvement at 24 hours after rtPA, cortical involvement, and new infarction on the 24- hour CT scan are relevant variables that can independently affect the LOS. These new variables may be useful for establishing policy in relation to the organization and planning of the health care system.
文摘针对目前腰部医学图像处理较少涉及分割并量化分析软组织的现状,提出一种腰部核磁共振图像(magnet-ic resonance imaging,MRI)中椎间盘分割及定量分析的算法:首先用改进的基于独立分量分析的主动外观模型(in-dependent component analysis based active appearance model,ICA-AAM)分割椎体,并基于最小描述长度(minimumdescription length,MDL)准则获得腰部弯曲曲线;利用上述分割结果,结合椎间盘成像特点和局部图像灰度投影,进一步实现基于马尔科夫随机场(Markov random field,MRF)的椎间盘快速无监督分割;通过分割结果判断并定量计算椎间盘突出程度。实验表明该算法快速有效,可以辅助医生诊断、治疗腰椎间盘突出等疾病。