Effect of intensive swimming training on lung volumes, airway resistances and on the maximal expiratory flow-volume relationship in prepubertal girls

The aim of the present study was to analyse the effect of 1 year of intensive swimming training on lung volumes, airway resistance and on the flow-volume relationship in prepubertal girls. Five girls [9.3 (0.5) years old] performing vigorous swimming training for 12?h a week were compared with a control group of 11 girls [9.3 (0.5) years old] who participated in various sport activities for 2 h per week. Static lung volumes, maximal expiratory flows (MEF) at 75, 50 and 25% of vital capacity, 1-s forced expiratory volume (FEV_1.0) and airway resistance (R _aw) were measured by means of conventional body plethysmograph techniques. Prior to the training period there were no significant differences between the two groups for any of the parameters studied. Moreover, for both groups, all parameters were within the normal range for children of the corresponding age. After 1 year of training, vital capacity (VC), total lung capacity (TLC) and functional residual capacity (FRC) were larger (P<0.05) in the girl swimmers than in the control group, while physical development in terms of height and weight was similar. FEV_1.0 (P<0.01), MEF₂₅, MEF₅₀ (P<0.05) and MEF₇₅ as well as the ratio MEF₅₀ / TLC (P<0.05) had increased in the girl swimmers but were unchanged in the control group. R _aw tended to be lower in the girl swimmers and higher in the control group. The results indicate that intensive swimming training prepuberty enhances static and dynamic lung volumes and improves the conductive properties of both the large and the small airways. As to the causative mechanism, it can be speculated that at prepuberty intensive swimming training promotes isotropic lung growth by harmonizing the development of the airways and of alveolar lung spaces.     

Non-invasive forced expiratory flow-volume curves to measure lung function in cats

Forced expiratory flow-volume curves were performed in 15 cats using the non-invasive thoracic compression techniques developed for use in human infants. Cats breathed through a face mask and pneumotachygraph from which flow and volume were obtained. Thoracic compression was applied from an inflatable bag in a non-expandable jacket surrounding the animal. Bag inflation at end inspiration was initiated by a computer pulse to a pressurized chamber. Processed signals from the pneumotachygraph determined maximum-forced expiratory flow at lung volume equivalent to functional residual capacity (FRC), termed V'maxFRC. Different compression pressures were used, and the highest value from a technically satisfactory flow-volume loop was taken as the result. Mean (+/- 95% CI) V'maxFRC was 422 (369-475) ml/s. Compared with infants of similar weight (V'maxFRC approximately 180 ml/s), cats had a much higher V'maxFRC. Tests repeated another day showed a mean (+/-95% CI) percentage difference between paired tests to be 2.8 (-12.6, +18.3)%. Non-invasive forced expiratory flow-volume measurements can be reliably obtained in sedated cats.     

Effect of tissue inhomogeneity on beta dose distribution of 32P

In a homogeneous medium of soft tissue the radiation dose distribution due to a nonuniformly distributed beta source can be calculated by convolution of the beta dose point kernel of the nuclide with the source distribution. A possible extension of the technique to the calculation of the dose distribution in heterogeneous media involving relatively simple geometric interfaces requires the knowledge of the resulting perturbation to the beta point kernels in individual media. We simulated a soft-tissue-bone planar interface by a polystyrene (PST)-aluminum junction and measured the change in beta dose from the dose value in homogeneous PST due to a point source of 32P using 7LiF thermoluminescent dosimeters. With the point source at the interface, the dose rates at 0-31, 125-156, and 283-314 mg/cm2 separations from the interface were increased by (12 +/- 3)%, (8 +/- 2)%, and (3 +/- 2)%, respectively, compared with homogeneous PST. With the point source at a PST-air planar interface to simulate a soft-tissue-air junction, the dose rates at 0-31, 139-170, and 283-314 mg/cm2 from the interface were decreased by (25 +/- 4)%, (11 +/- 7)%, and (5 +/- 2)%, respectively. The changes in dose rates for these two interfaces have also been measured with degraded spectra of 32P. Comparison of the experimental data with Monte Carlo calculation for a point source and the two-group method of calculation for a plane source is also presented.     

部分液体通气对急性肺损伤小猪肺组织结构及气体交换的影响

目的：探讨以perfluorocarbon (PFC)为媒介的部分液体通气(PLV)对灌洗后急性肺损伤小猪肺组织病理变化及气体交换的影响。 方法： 采用肺灌洗诱导小猪急性肺损伤(ALI)后，将动物分为两组：PLV组和传统机械通气（CV）组。分别在ALI前、ALI及ALI后1、2、3、4 h 6个时点观察动脉血气指标的变化，实验结束后取8个不同部位的肺组织做病理切片。 结果： PLV组灌注PFC后PaO2高于CV组、AaDO2显著低于CV组；病理切片比较：PLV组病变轻于CV组，两组上部肺叶病变均轻于下部肺叶，具有统计学差异（P<0.05），CV组前部肺叶病变轻于后部肺叶，具有统计学差异（P<0.05），PLV组肺组织炎症细胞浸润程度明显轻于CV组肺组织。 结论： 急性肺损伤后，以PFC为媒介的部分液体通气能明显提高肺氧合能力，升高PaO2。     

Effect of tissue inhomogeneity on dose distribution of point sources of low-energy electrons

Perturbation in dose distributions of point sources of low-energy electrons at planar interfaces of cortical bone (CB) and red marrow (RM) was investigated experimentally and by Monte Carlo codes EGS and the TIGER series. Ultrathin LiF thermoluminescent dosimeters were used to measure the dose distributions of point sources of 204Tl and 147Pm in RM. When the point sources were at 12 mg/cm2 from a planar interface of CB and RM equivalent plastics, dose enhancement ratios in RM averaged over the region 0-12 mg/cm2 from the interface were measured to be 1.08 +/- 0.03 (SE) and 1.03 +/- 0.03 (SE) for 204Tl and 147Pm, respectively. The Monte Carlo codes predicted 1.05 +/- 0.02 and 1.01 +/- 0.02 for the two nuclides, respectively. However, EGS gave consistently 3% higher dose in the dose scoring region than the TIGER series when point sources of monoenergetic electrons up to 0.75 MeV energy were considered in the homogeneous RM situation or in the CB and RM heterogeneous situation. By means of the TIGER series, it was demonstrated that aluminum, which is normally assumed to be equivalent to CB in radiation dosimetry, leads to an overestimation of backscattering of low-energy electrons in soft tissue at a CB-soft-tissue interface by as much as a factor of 2.     

Maximal expiratory flow-volume patterns in allergic rhinitis. Characteristic flow-volume patterns of the lower airways

On 37 patients with nasal allergy and 37 non-smoking healthy volunteers, maximal expiratory flow-volume curve and volume-time curve were obtained. To find the characteristic flow changes, the flow curves were classified into five patterns from type A to type E. The results showed that the incidence of type A was significantly lower in patients with nasal allergy than in the control group, while the rate of type E was significantly higher at 46% and the rate of type B was particularly high (32.4%) in the patient group. It was demonstrated that 77% of the subjects provided B or C flow-volume curves, while those with pale nasal mucous membranes developed D and E formats. In patients with nasal allergy, these patterns are useful in diagnosing remarkable differences in the lower airways.     

部分液体通气治疗家猪急性肺损伤的抗炎效应

目的：探讨部分液体通气治疗肺灌洗诱导的 急性肺损伤家猪模型时，是否具有抗炎作用。方法：16只健康家猪，采 用生理盐水肺内灌洗复制急性肺损伤模型，随机分为部分液体通气组及机械通气组给予不同 治疗，观察其肺脏湿/干比值及肺通透指数，观察其血浆、支气管肺泡灌洗液及肺组织匀浆 中TNF-α、MDA含量及SOD、MPO活性。结果：（1）部分液体通气组家猪 肺脏湿/干比值、肺通透指数及支气管肺泡灌洗液中白细胞计数明显低于机械通气组。（2） 肺组织MDA、MPO含量部分液体通气组明显低于机械通气组，但两组间SOD活性无明显差别。 （3）部分液体通气组支气管肺泡灌洗液及肺组织匀浆中TNF-α含量明显低于机械通气组。 结论：部分液体通气改善动物肺损伤指标，提示以氟碳化合物为呼吸媒 介的部分液体通气对肺灌洗诱导的急性肺损伤家猪具有抗炎效应。     

Simple parametrizations of maximum expiratory flow-volume curves

Summary Four elementary mono-compartmental lung models yield parametrizations of Maximal Expiratory Flow-Volume curves of normal subjects. The respective analytical functions are fitted to the measured curves and the mathematically derived ventilation indices are compared with standard measured data. While individual values of resistance and compliance seem devoid of a simple physical interpretation, their product indeed matches the models.     

部分液体通气对猪急性肺损伤的影响

目的: 在肺灌洗诱导的急性肺损伤(ALI)家猪实施以氟碳(PFC)为媒介的部分液体通气(PLV), 观察其对肺气体交换及血液动力学的影响, 并比较PLV及气体通气两种方式对肺形态学的影响, 以探讨PLV改善肺气体交换的机制。方法: 12头体重为25-30 kg的健康雌猪,麻醉后经肺灌洗建立ALI模型。随机分为PLV组及CV(气体通气组)。对照组以呼吸机行常规机械通气, PLV组动物经气管导管肺内灌以15 mL/kg的PFC,然后以与对照组同样的呼吸参数行机械通气。每小时记录肺气体交换及血液动力学参数的变化。于实验结束后处死动物, 取肺标本送病理分析。 结果: PLV组肺气体交换明显改善,而血液动力学在整个实验过程中基本维持稳定。组织学检查: 光学显微镜下可见两组均为肺不张、肺气肿及肺过度膨胀交替出现,肺泡间质因水肿及细胞渗出而扩展。PLV组与CV组比较显示较轻微的肺不张、肺内炎性细胞渗出、肺出血及肺间质扩张。PLV组动物腹侧肺组织学损伤改变明显较背侧轻微。 结论: 在肺灌洗诱导的急性肺损伤幼猪, 以氟碳为媒介的部分液体通气可明显地改善肺气体交换,并无明显的血液动力学损伤。同时可见PLV相对于对照组明显减轻的肺组织学损伤及肺泡扩张, 证实PLV具一定的肺保护作用。     

Influence of matching volume on reproducibility of maximal expiratory flow-volume curves

We examined the influence of "matching volume" on intrasubject variability of the descending limb of maximal expiratory flow-volume (MEFV) curves on air and helium-oxygen (He) in 18 healthy subjects and 28 patients with airflow limitation. Duplicate forced expirations were analysed according to four methods of alignment. With the first method, flows corresponding to identical percentiles of separate FVC (SEPVC) were compared. With the remaining three, we aligned curves at TLC, mid-vital capacity (VC50) and RV, respectively, for comparison of: a) flow at identical percentiles of the averaged FVC and b) expired volume at identical percentiles of the averaged peak flow. In healthy subjects, variability of flow at 50% and 75% of expired FVC (FEF50 and FEF75) did not change significantly with method, except that FEF75 on air varied more with method SEPVC than with VC50. In airflow limitation, FEF75 was significantly less reproducible when curves were matched at RV than at TLC, both on air and He. Over the latter part of expiration, an arbitrary index of variability of flow-defined volume also indicated that method RV gave the poorest precision in patients. We conclude that selection of matching volume does not influence the variability of MEFV-curves in health. In airflow limitation, however, TLC appears to be the most reliable volume for alignment.     

Accuracy of clinical manoeuvres in detection of minimal ascites

A study was conducted to assess the clinical accuracy of various clinical manoeuvres and signs used routinely for detection of ascites. Sixty-six patients admitted in medical ward of a teaching hospital after initial screening by a consultant were selected. Exclusion criteria were; cases with previous history of ascites, who had undergone paracentesis in the recent past or with evidence of ascites from history. Another clinician blind to history and clinical details assessed the presence of ascites by the selected methods a sonographer blind of clinical and historical details assessed the cases for presence of ascitic fluid. The clinical findings were compared using ultrasonographic (USG) findings as gold standard. Ascites was detected in 35 patients by USG. the mean weight and abdominal girth of study subjects with or without ascites were comparable (p > 0.05). Sensitivity of auscultatory percussion was highest (65.7%) followed by flank dullness (57.1%) and least for fluid wave sign (20.0%). Fluid wave sign had the highest specificity (100%). We found that none of the manoeuvres studied for detection of ascites was both highly sensitive and specific. However, auscultatory percussion could be useful for initial screening of patients to detect ascites.     

部分足截肢部位对步态的影响

目的 部分足截肢是临床截肢手术中最常见的截肢类型,跖趾关节部位、跖骨部位和Lisfrane关节部位是PFA最典型的三种截肢平面,分析经这些平面的部分足截肢对步态的影响,将有助于相关辅具的设计和评价。方法 采用Footscan平板式足底压力测试系统和Optotrak三维运动分析系统,以跨步长、步频、步速、足底各区域的峰值压力、冲量、接触时间、接触面积为特征参量,对这三种截肢平面患者进行了步态分析。结果 分析结果表明,三种不同足部截肢平面中,残足越短,跨步长越小,双足承重时间差越明显;MTP的峰值压力主要在跖骨处和足跟处,TMA和Lisfrane的峰值压力集中在足中部和足跟处。结论 推断在设计和评价不同足部截肢平面的相关辅具时,不同截肢平面辅具有相应差异。