Effect of azelastine and ketotifen on the bronchial and skin responses to platelet-activating factor in humans

In a randomized, double-blind placebo-controlled study we investigated the effect of single oral doses of 8 mg azelastine and 2 mg ketotifen on the immediate response to platelet-activating factor (PAF) inhalation and to increasing doses of PAF injected intradermally. Bronchial provocation with 100 micrograms of PAF resulted in marked bronchoconstrictor responses, but neither azelastine nor ketotifen had any significant effect on these responses. Intradermal injection of PAF (100, 200 and 400 ng) resulted in a dose-related weal and flare response. Azelastine and ketotifen both caused significant reductions in this response (P less than 0.002-P less than 0.01). There was no significant difference between the effect of the two drugs.     

Cardiac Output Is a Sensitive Indicator of Difference in Exercise Performance Between Single and Dual Sensor Pacemakers

Although multisensor pacing may compensate the inadequacy of rate adaptation in a single sensor system, the clinical role of multisensor driven rate adaptive pacing remains unclear. We compared the performance between single sensor and dual sensor driven pacemakers using exercise cardiac output (CO) as a marker of cardiac performance. Eight patients with a mean age of 63 ± 3 years implanted with a dual sensor pacemaker driven by combined activity (ACT) and QT interval sensors were studied in the ACT-, QT- only and the dual QT+ACT-VVIR modes. Patients performed submaximal and maximal exercise tests with CO assessed by carbon dioxide rebreathing method. Comparing the HR response based on the change in metabolic workload, the ACT- VVIR “overpaced,” the QT'VVIR “underpaced,” and the QT+ACT-VVlR achieved the best approximation to normal. The percentages of CO increase in ACT-WIR and QT+ACT-VVIR modes over resting CO were higher at 1 minute of exercise (295 ± 85% and 165 ± 49%, respectively) compared to the QT-VVIR mode (81 ± 40%, P ≤ 0.05). During exercise, stroke volume cbanges from baseline were similar between ACT-VVIR and QT + ACT-VVIR modes, but a compensatory increase in stroke volume occurred in the QT-VVIR mode during submaximal exercise (50 ± 11 mL vs 24 ± 17 mL in the QT+ACT-VVlR and 14 ± 4 in ACT-VVIR, P ≤ 0.003). There was no difference in the maximal exercise workload, exercise duration and CO at the submaximal and maximal exercise between the 3 sensor modes. Thus, exercise capacity is a poor indicator of sensor performance while CO measurement is a sensitive indicator of sensor mode differences especially at low workload exercise. The ACT- VVIR gave the fastest increase in CO at start of exercise at the expanse of overpacing, whereas the “under-paced” QT-VVIR compensated for the slower rate increase by utilizing contractility reserve during submaximal exercise. Dual sensor pacing, by achieving the best heart rate to workload relationship, provided a CO response without overpacing or using contractility reserve during exercise.     

Abnormal Vasovagal Reaction, Autonomic Function, and Heart Rate Variability in Patients with Paroxysmal Atrial Fibrillation

The aim of this study was to evaluate the cardiovascular autonomic function and vasovagal reaction in patients with paroxysmal atrial fibrillation without significant structural heart disease. Twenty-eight patients with paroxysmal atrial fibrillation (9 patients were categorized to have autonomic-mediated atrial fibrillation while atrial fibrillation in other patients was nonautonomic mediated) and 19 normal control subjects were recruited. Cardiovascular autonomic function tests included measuring heart rate response to standing, deep breathing, Valsalva maneuver, baroreflex sensitivity, 24-hour heart rate variability, and also head-up tilt test. Compared with normal subjects, no significant autonomic dysfunction was found in patients with autonomic-mediated and nonautonomicmediated atrial fibrillation. All subjects had negative baseline tilt test. With isoproterenol provocation, six patients developed atrial fibrillation. Four of 9 patients and 3 of 19 patients with autonomic mediated and nonautonomic mediated atrial fibrillation had a positive tilt test respectively, while none occurred in the controls. A significant percentage (32%) of patients with paroxysmal atrial fibrillation had episodes of atrial fibrillation provoked by changes in autonomic tone, although there was no underlying abnormal cardiac autonomic function nor sympathetic-parasympathetic imbalance. A heightened susceptibility to vasovagal cardiovascular response may have important implications on the occurrence and symptomatology of patients with paroxysmal atrial fibrillation.     

A Comparison of Transvenous Atrial Defibrillation of Acute and Chronic Atrial Fibrillation and the Effect of Intravenous Sotalol on Human Atrial Defibrillation Threshold

The comparative efficacy and safety of transvenous defibrillation for acute and chronic AF and the effect of antiarrhythmic agents on this therapy have not been evaluated. Transvenous atrial defibrillation was performed in 25 patients with chronic AF and 13 patients with acute AF by delivering R wave synchronized, biphasic shocks between the right atrium and coronary sinus. The lowest energy and voltage resulting in successful defibrillation were considered to be atrial defibrillation threshold (ADFT). Intravenous sotalol (1.5 mg/kg) was thengiven over 15 minutes and ADFT was determined again. The mean ADFT was 1.5 /and 3.6 J for acute and chronic AF, respectively, and the threshold was highly reproducible. Sotaloi reduced ADFT in patients with acute AF while the reduction in chronic AF group was not significant. There was no significant increase in creatinine kinase nor reduction in blood pressure, but prolonged pause after successful defibrillation required ventricular supporting pacing. We conclude that transvenous atrial defibrillation is a safe and effective means for defibrillating both acute and chronic AF. ADFT was lower in acute AF than in chronic AF. ADFT was highly reproducible during repeated defibrillation. Sotalol reduced ADFT in acute AF and to a lesser extent in chronic AF, and increased the defibrillation success rate. Ventricular pacing will often be required because of prolonged pause after successful defibrillation.     

对“联合肝脏离断和门静脉结扎的二步肝切除术”的述评

联合肝脏离断和门静脉结扎的二步肝切除术(ALPPS)是一个非常新的外科手术.该手术主要针对因未来剩余肝脏体积较小而不能接受大范围肝切除术的T分期较晚的肝癌患者而设计的.ALPPS第1步手术后,患者剩余肝脏对手术的反应非常强烈,使得肝脏体积急剧增生.因而可在第1步手术后1周左右施行第2步手术以切除所有肝内肿瘤(R0切除).本文追溯ALPPS的发展历史,描述该手术的传统步骤和手术的偏离等情况,分析该手术的短期疗效.尽管ALPPS后零死亡已有报道,但初步的研究结果表明:ALPPS的手术死亡率和并发症发生率仍然较高.ALPPS后尚没有明确的长远治疗肿瘤效果的报道.该手术在肝硬化肝癌患者中能否安全施行尚有疑问.     

Biphasic rise of serum immunoglobulins G and A and sex influence on serum immunoglobulin M in normal Chinese children

A study was conducted on 751 healthy children from child health clinics, kindergartens and schools, and 80 normal adults to establish reference ranges for serum immunoglobulins (Ig) G, A and M concentrations in normal Chinese. Serum IgG, IgA and IgM concentrations were determined by nephelometry. Serum IgG and IgA were shown to have a significant rise during the preschool age as well as at puberty with a plateau phase in between. This biphasic maturation profile has not been reported in Caucasians and the reasons for the observed difference have yet to be elucidated. Serum IgM concentrations were shown to be higher in females than in males, reaching significance in most age groups beyond 4 years of age. The difference between the two sexes in Chinese was of similar magnitude as that reported for Blacks and Caucasians, that is, 30%. Our findings support the hypothesis that the human X chromosome may carry quantitative genes for IgM.     

The Range of Sensors and Algorithms Used in Rate Adaptive Cardiac Pacing

Implantable sensors play an important role in physiological cardiac pacing. Sensors can be classified according to the technical methods in which sensing is achieved: the sensing of the evoked ventricular response, intrathoracic impedance and body acceleration forces, and the incorporation of special sensors on pacing electrodes. These sensors differ in their relative merits in terms of speed, proportionality, sensitivity, and specificity of rate response. The efficacy of a sensor can be significantly modified by the algorithm used in relating sensor signal to a pacing rate change. The currently available types of sensors and algorithms are summarized and compared in this review article. The relative merits of these sensors and algorithms form the basis for designing a multisensor pacing system.     

The Radiology of Bronchial Atresia Radiographic,CT and Bronchography Correlation

We examined two patients with bronchial atresia. Both cases involved the left upper lobe: the anterior and the lingular segments respectively. Mucoid impaction and hyperinflation seen with radiography or computed tomography (CT) are typical findings. Bronchography in conjunction with bronchoscopy is an efficient means to confirm the atretic segment as well as the patency of the proximal bronchi respectively.