Transient ventilatory response to CO2 as a function of sleep state in full-term infants

The influence of sleep state on the transient (i.e., initial 60 s) and steady-state ventilatory responses to 2% CO2 inhalation was studied in 19 healthy full-term infants. A nasal mask pneumotachometer was used to measure ventilation and end-tidal CO2 partial pressure (PCO2) and enabled abrupt changes in the inspired gas concentration to be made. The magnitude of the change in minute ventilation for both the transient and steady-state responses to CO2 was not statistically different between active (AS) and quiet (QS) sleep. Nonetheless the greater variability in minute ventilation during AS compared with QS continued throughout the period of CO2 inhalation and was associated with a more variable change in ventilation in the individual infants during AS. There was a greater increase in end-tidal PCO2 over the first 60 s during AS (3.3 +/- 0.3 vs. 2.6 +/- 0.2 Torr, in AS and QS, respectively, P less than 0.03). This may indicate a smaller initial increase in alveolar ventilation, relative to CO2 delivery to the lungs, in response to CO2 inhalation during AS. Asynchronous chest wall movements were more common during AS than QS (P less than 0.005) and did not change with CO2. The inconsistent transient ventilatory response to CO2 during AS compared with QS may be important in the behavior of infants to spontaneous episodes of hypercapnia occurring during AS.     

Evaluation of dust respirators for elimination of mouse aeroallergens

The efficiency of various dust respirators for eliminating mouse allergens [mouse urine proteins (MUP), pelts proteins (MPP) and serum albumin (MSA)] were evaluated with use of low-volume air samplers and immunochemical methods. Three kinds of dust respirators from one manufacturer which have different efficacy in the exclusion of dust particles were put on the fiber glass filter in each air sampler. Then the air in a mouse housing room was sampled. The allergens passed through the respirators, were trapped in the fiber glass filters, and then extracted from the filters. The allergens of MUP and MPP in the extract were measured by an inhibition method of fluorometric enzyme-linked immunosorbent assay (ELISA) for IgE antibody and those of MSA measured by a fluorometric sandwich ELISA. The respirator with the lowest capability of exclusion was found to eliminate 65-86% of respective allergens. The other two respirators with higher powers eliminated 98% of MUP. MPP and MSA were eliminated to undetectable levels through these respirators. This study provided a means for the evaluation of dust respirators for animal aeroallergens.     

Effect of atenolol on ventilatory and cardiac function in asthma.

The effects on ventilatory and cardiac function of atenolol, a new cardioselective beta-adrenoceptor blocking agent, were compared with those of practolol in a double-blind trial in 12 patients with asthma. Both drugs impaired ventilatory function--atenolol insignificantly and practolol significantly. Atenolol was if anything more cardioselective than practolol. Neither drug interfered significantly with the bronchodilator response to inhaled isoprenaline. Atenolol is suitable for use in patients for whom practolol would formerly have been chosen because of its cardioselectivity.     

Effect of endurance exercise training on ventilatory function in older individuals

To evaluate the effect of endurance training on ventilatory function in older individuals, 1) 14 master athletes (MA) [age 63 +/- 2 yr (mean +/- SD); maximum O2 uptake (VO2max) 52.1 +/- 7.9 ml . kg-1 . min-1] were compared with 14 healthy male sedentary controls (CON) (age 63 +/- 3 yr; VO2max of 27.6 +/- 3.4 ml . kg-1 . min-1), and 2) 11 sedentary healthy men and women, age 63 +/- 2 yr, were reevaluated after 12 mo of endurance training that increased their VO2max 25%. MA had a significantly lower ventilatory response to submaximal exercise at the same O2 uptake (VE/VO2) and greater maximal voluntary ventilation (MVV), maximal exercise ventilation (VEmax), and ratio of VEmax to MVV than CON. Except for MVV, all of these parameters improved significantly in the previously sedentary subjects in response to training. Hypercapnic ventilatory response (HCVR) at rest and the ventilatory equivalent for CO2 (VE/VCO2) during submaximal exercise were similar for MA and CON and unaffected by training. We conclude that the increase in VE/VO2 during submaximal exercise observed with aging can be reversed by endurance training, and that after training, previously sedentary older individuals breathe at the same percentage of MVV during maximal exercise as highly trained athletes of similar age.     

Prediction of neurotoxins based on their function and source

We have developed a method NTXpred for predicting neurotoxins and classifying them based on their function and origin. The dataset used in this study consists of 582 non-redundant, experimentally annotated neurotoxins obtained from Swiss-Prot. A number of modules have been developed for predicting neurotoxins using residue composition based on feed-forwarded neural network (FNN), recurrent neural network (RNN), support vector machine (SVM) and achieved maximum accuracy of 84.19%, 92.75%, 97.72% respectively. In addition, SVM modules have been developed for classifying neurotoxins based on their source (e.g., eubacteria, cnidarians, molluscs, arthropods have been and chordate) using amino acid composition and dipeptide composition and achieved maximum overall accuracy of 78.94% and 88.07% respectively. The overall accuracy increased to 92.10%, when the evolutionary information obtained from PSI-BLAST was combined with SVM module of source classification. We have also developed SVM modules for classifying neurotoxins based on functions using amino acid, dipeptide composition and achieved overall accuracy of 83.11%, 91.10% respectively. The overall accuracy of function classification improved to 95.11%, when PSI-BLAST output was combined with SVM module. All the modules developed in this study were evaluated using five-fold cross-validation technique. The NTXpred is available at www.imtech.res.in/raghava/ntxpred/ and mirror site at http://bioinformatics.uams.edu/mirror/ntxpred.     

成年人脂肪体重、去脂体重和肺通气功能的关系

本文旨在研究分析成年人去脂体重(fat free mass,FFM)、脂肪体重(fat mass,FM)和肺通气功能的关系。随机抽取黑龙江省部分地区19~81岁健康成年人群1307人(男性372人,女性935人),测量身高、体重,采用身体成分仪和肺功能仪分别检测FFM、FM和肺通气功能,并采用Pearson相关分析、独立样本t检验和多元逐步回归等统计学方法分析FFM、FM和肺通气功能的关系。结果显示,无论性别,年龄均与脂肪体重指数(FM index,FMI)呈正相关(P0.001),去脂体重指数(FFM index,FFMI)和用力肺活量(forced vital capacity,FVC)、用力呼气一秒量(forced expiratory volume in one second,FEV1)、最高呼气流量(peak expiratory flow,PEF)、用力呼出25%肺活量时呼气流量(forced expiratory flow at25%of forcedvital capacity,FEF25%)均呈正相关(P0.01),FMI和FVC、FEV1、FEF75%呈负相关(P0.05)。男性FMI和最大呼气中段流量(maximal mid-expiratory flow,MMEF)呈负相关(P0.05)。无论性别,FFMI对于FVC作用大于FMI,而对于FEV1,男性FMI作用大于FFMI,女性则反之。无论性别,FFMI升高,PEF和FEF25%也升高,而FMI对二者无作用。无论性别,FMI升高,FEF75%降低,而FFMI对其无作用。FMI升高,男性MMEF降低,女性无明显改变。本研究结果表明,FFM和FM均是影响肺通气功能的独立因素,反映骨骼肌力的FFM与肺通气功能呈正相关,FM与肺通气功能呈负相关。FFM和FM对肺通气功能作用大小存在差别。     

Effects of O2 on the ventilatory response to CO2 in preterm infants.

To measure the effects of O2 on the ventilatory response to CO2 in preterm infants, we studied eight babies (birth wt 1-2 kg; gestational age 32-36 wk) 10 times during the first 11 days of life. After breathing 21% O2 for 3 min, they were given 15%, 21%, 40%, or 100% O2 for 4 min and then 2% CO2 plus the various concentrations of O2 for 4 min each. The mean slopes of the CO2 response curves were 0.013, 0.027, 0.034, and 0.056 1/(min-kg-mmHg PACO2) with 15%, 21%, 40%, and 100% inspired O2, respectively. Thus, the more hypoxic the infant, the flatter was the response to CO2. These findings suggest that in preterm infants 1) the response to inhaled CO2 is the reverse of that seen in adult man where the higher the inspired O2 concentration, the flatter the response, and 2) the respiratory center is depressed during hypoxia.