Exhaled nitric oxide in healthy children: Variability and a lack of correlation with atopy

Nitric oxide (NO) is a free radical produced by several lung cells via the enzyme nitric oxide synthetase (NOS) and can be easily measured in exhaled air by chemiluminescence analysis. As the iso-enzyme iNOS may be induced by cytokines and endotoxin, NO is elevated in several chronic inflammatory airway diseases. Prior to using exhaled nitric oxide (eNO) as a non-invasive marker of airway inflammation in daily routine, the role of possibly influencing factors such as age, time of the day, smoking exposure and intra-individual variability have to be clarified. NO concentrations were measured in 107 healthy children aged 4–18 years at an expiratory flow of 184 ml/s. Spirometry and a skin-prick test were performed and a questionnaire on family history of atopy, personal symptoms of atopic disease and smoke exposure was completed. For intra-individual variability nitric oxide was measured in six children three times daily on 6 consecutive days. Median eNO concentration was 5.7 p.p.b., and increased significantly with age but did not vary with gender. No correlation was found between eNO and smoke exposure, positive skin-prick test, FEV ₁, MEF₂₅ and time of the day. There was no circadian rhythm found in the six children measured on 6 consecutive days, but the eNO showed an intra-individual coefficient of variation of 25.9%. With the help of a two-compartment model of the lung the alveolar NO concentration was estimated to be 4.1 p.p.b and was shown to be constant with age, whereas the airway part of NO steadily increased with age. When comparing eNO values with standardized measurement techniques, the age of the children and the large intra-subject coefficient of variation have to be taken into account, whereas in healthy children subject-specific factors such as atopic history, gender and skin test reactivity did not affect eNO measurement.     

Eyelid movements during blinking in patients with Parkinson's disease.

We examined eyelid movements during spontaneous, voluntary, and trigeminal reflex blinks in 16 patients with mild to moderate Parkinson's disease (PD) off medication and 14 controls. Voluntary and reflex blink amplitudes tended to be smaller than normal for PD patients, whereas eyelid kinematics (amplitude-maximum velocity relationship) for all three blink types were normal. Spontaneous blink rate was less than normal for 10 patients and abnormally high for 6 patients. A significant positive correlation between spontaneous blink amplitude and blink rate was found. These observations suggest that PD modifies the gain of a premotor blink circuit shared by spontaneous, voluntary, and reflex blinks.     

文拉法辛与三环类抗抑郁药治疗抑郁症痊愈率的循证医学研究

目的　比较文拉法辛与三环抗抑郁药治疗抑郁症临床痊愈率的差异。方法　应用循证医学的Me-ta分析,采用固定效应模型(fixed effects model,FEM)法对符合标准的16项对照研究文献进行评价。结果　文拉法辛与三环抗抑郁药治疗抑郁症的临床痊愈率不同,差异有显著性(χ2=4.773,df=1,P<0.05);综合的ORs=1.36,95%CI为1.04~1.78。提示文拉法辛治疗抑郁症的临床痊愈率是三环抗抑郁药的 1.36倍。结论　治疗抑郁症,文拉法辛比三环抗抑郁药有更可靠的临床痊愈率。     

Ventricular rate smoothing for atrial fibrillation: a quantitative comparison study.

AIMS: To quantitatively compare the ventricular rate-smoothing (VRS) effects of different ventricular pacing (VP) protocols for atrial fibrillation (AF). METHODS AND RESULTS: Using a recently developed open-source model that can simulate the ventricular response in AF and VP, the performance of fixed-rate pacing and four previously published VRS algorithms were assessed by the mean RR (mRR), the root mean square of successive RR differences (RMSSD), the percentage of ventricular senses (VS%), and the percentage of short RR intervals (sRR%). All pacing protocols cause rate-dependent reduction of RMSSD, VS%, and sRR% with or without shortening of mRR compared to spontaneous AF. Fixed-rate pacing was more sensitive to the intrinsic rate than the VRS algorithms. The performance was generally comparable between different VRS algorithms, although higher mRR and VS% can be achieved at the expense of larger RMSSD and sRR%. CONCLUSION: The effect of VP on ventricular rhythm in AF depends on both intrinsic rate and the aggressiveness of the pacing protocol. Adequate rate control is necessary for effective operation of the VRS algorithm. Choosing VRS algorithm should balance between the beneficial effects of rate regularization and the negative effects of increasing heart rate and percentage of VP.     

A mathematical analysis of kinetic characteristics of oxidative phosphorylation in the animal brain under hypoxic conditions

The kinetic dependence of the rate of oxidative phosphorylation (ADP/t) on the concentration of exogenous ADP has been mathematically analyzed in the brain mitochondria. This relationship has been approximated by a mathematic model under various vital conditions. We propose an analytical approach to calculating the characteristics of oxidative phosphorylation and predicting the kinetics of oxidative ATP synthesis in brain mitochondria of animals subjected to hypoxia.     

A recycling framework for the construction of Bonferroni‐based multiple tests

In this paper we describe Bonferroni‐based multiple testing procedures (MTPs) as strategies to split and recycle test mass. Here, ‘test mass’ refers to (parts of) the nominal level α at which the family‐wise error rate is controlled. Briefly, test mass is split between different null hypotheses, and whenever a null hypothesis is rejected, the part of α allocated to it may be recycled to the testing of other hypotheses. These recycling MTPs are closed testing procedures based on raw p‐values associated with testing the individual null hypotheses, and the class of such MTPs includes, for example, serial and parallel gatekeeping, fallback and Holm procedures. Graphical displays and a concise algebraic notation are provided for such MTPs. This recycling approach has pedagogical advantages and may facilitate the tailoring of MTPs for different purposes. Copyright © 2009 John Wiley & Sons, Ltd.     

胸膜活检阳性率的主要相关因素

分析了92例胸膜活检资料,认为其阳性率与下述因素有关:疾病种类、病例选择、活检器械、取材方法及技术、重复检查、临床医师与病理医师的配合。     

Surgical treatment for carcinoma of the papilla of vater

Eighty of 89 patients who underwent radical resection (resectability 89.9%) for carcinoma of the papilla of Vater between 1976 and 1992 were retrospectively reviewed. Seventy-three patients underwent pancreaticoduodenectomy (PD) and 7 underwent pylorus-preserving pancreaticoduodenectomy (PPPD). The postoperative mortality rate was only 3.8% (3 patients). The 3- and 5-year survival rates were 63.6% and 57.4%, respectively. Important factors influencing long-term survival were Stage (clinical stage = Stage), microscopic lymph node metastasis (n), duodenal wall invasion (d), vascular invasion (v), and the epithelium of origin. Early carcinoma of the papilla of Vater is defined as tumor in which invasion is limited within the papilla of Vater; in particular, carcinomatous invasion is within the muscle of Oddi (d₀) with n₀. PD and/or PPPD with radical lymph node dissection should be performed for carcinoma of the papilla of Vater, as these procedures can be performed with low morbidity and mortality.     

Heart rate variability and apnea during sleep in Down's syndrome

Autonomic system dysfunction has been reported to occur frequently in patients with Down's syndrome (DS) and is constituted mainly by an imbalance between the sympathetic and vagal systems. The analysis of heart rate variability (HRV) during sleep is a quantitative reliable method for studying such a mechanism, but it has not yet been extensively and adequately applied in DS. In this study, HRV during sleep was evaluated in seven DS patients and in six normal controls, by also controlling for the presence of sleep apnea or arousal. The main results were an increased sympathetic function (low-frequency component of HRV) and a decreased vagal activity (high-frequency component of HRV) in DS with respect to normal controls, during apnea-free periods. Moreover, the presence of apnea, in DS, induced a further significant increase in low-frequency and very low-frequency components of HRV during sleep Stage 2. This study provides additional evidence of a brainstem dysfunctioning in DS, responsible for the abnormal imbalance between the sympathetic and vagal systems and confirms the brainstem involvement already suggested in the literature in order to explain brainstem-auditory evoked potential abnormalities and central sleep apnea in these patients.