慢性阻塞性肺疾病患者血清MMP-9检测及意义

目的探讨基质金属蛋白酶-9（MMP-9）在慢性阻塞性肺疾病（COPD）气道炎症发生、发展过程中的作用。方法采用ELISA法测定56例COPD患者（观察组）急性加重期（56例）及稳定期（52例）血清MMP-9水平,并与50例同期健康体检者（对照组）比较,对MMP-9表达与第一秒用力呼气容积占预计值的百分比（FEV1%）、一秒钟用力呼气容积占用力肺活量的百分比（FEV1/FVC）%、残气量与肺总量之比（RV/TLC）%行相关性分析。结果 COPD急性加重期及稳定期患者血清MMP-9水平均明显高于对照组（P〈0.01,P〈0.05）,且与FEV1%呈负相关（r=-0.712,P〈0.05）,与（RV/TLC）%呈正相关（r=0.691,P〈0.05）。结论 MMP-9参与了COPD气道炎症的发生、发展;检测血清MMP-9水平有助于判断COPD病情及预后。     

慢性阻塞性肺疾病患者辅助性T细胞17/调节性T细胞变化及其与肺功能的相关性研究

目的观察慢性阻塞性肺疾病(COPD)患者辅助性T细胞17(Th17细胞)/调节性T细胞(Treg细胞)变化,探讨其与肺功能的相关性。方法选取2013年9月—2015年9月四川省成都市西区医院收治的老年COPD稳定期患者36例作为稳定期组,COPD急性加重期患者29例作为急性加重期组;另选取同期在本院体检健康者50例作为对照组,其中吸烟者22例作为吸烟对照组,不吸烟者28例作为正常对照组。比较4组受试者外周血Th17细胞分数、Treg细胞分数、Th17细胞/Treg细胞比值,血清IL-17、IL-10水平及肺功能指标〔第1秒用力呼气容积占预计值百分比(FEV1%)、用力肺活量占预计值百分比(FVC%)及第1秒用力呼气容积与用力肺活量比值(FEV1/FVC)〕,并分析外周血Th17细胞分数、Treg细胞分数及Th17细胞/Treg细胞比值与肺功能指标的相关性。结果急性加重期组和稳定期组患者外周血Th17细胞分数、Th17细胞/Treg细胞比值及血清IL-17水平高于吸烟对照组和正常对照组,外周血Treg细胞分数及血清IL-10水平低于吸烟对照组和正常对照组(P0.05);急性加重期组患者外周血Th17细胞分数、Th17细胞/Treg细胞比值及血清IL-17水平高于稳定期组,外周血Treg细胞分数及血清IL-10水平低于稳定期组(P0.05);吸烟对照组受试者外周血Th17细胞分数、Th17细胞/Treg细胞比值高于正常对照组(P0.05)。4组受试者FVC%比较,差异无统计学意义(P0.05);急性加重期组和稳定期组患者FEV1%、FEV1/FVC低于吸烟对照组和正常对照组,急性加重期组患者FEV1%、FEV1/FVC低于稳定期组(P0.05)。Pearson相关性分析结果显示,外周血Th17细胞分数与FEV1、FEV1%/FVC呈负相关(r值分别为-0.736、-0.694,P0.05),Th17/Treg细胞比值与FEV1、FVC%、FEV1%/FVC呈负相关(r值分别为-0.892、-0.222、-0.748,P0.01),而外周血Treg细胞分数与FEV1、FVC%、FEV1%/FVC呈正相关(r值分别为0.837、0.368、0.822,P0.01)。结论 COPD患者存在Th17/Treg细胞失衡,而Th17/Treg细胞失衡与吸烟、COPD病情变化及肺功能损伤等密切相关。     

COPD患者HMGB1与肺功能的相关性分析

目的研究COPD病人在急性加重期和临床缓解期血中高迁移率族蛋白B1（HMGB1）、肺功能的变化及其相关性分析。方法分别测定COPD病人在急性加重期和经过治疗进入临床缓解期血清HMGB1的浓度及肺功能值（FEV1%、FEV1/FVC）,数据用SPSS 13.0作统计分析。结果急性加重期HMGB1浓度值高于缓解期（P〈0.05）;急性加重期FEV1%低于缓解期（P〈0.05）;加重期和缓解期HMGB1浓度值和FEV1%呈直线负相关（P〈0.05）。结论 1.HMGB1作为炎性分子,在COPD急性加重期血清浓度显著高于缓解期。2.在COPD中HMGB1浓度和肺功能明显相关,提示对于疾病严重程度的判断可能有一定意义。     

慢性阻塞性肺病患者肺炎衣原体感染临床分析

目的 调查慢性肺炎衣原体（Cpn）感染和慢性阻塞性肺病（COPD）之间可能的相关性.方法 选取来我院就诊的COPD急性加重期患者60例,COPD稳定期患者40例,以及同期来院参加健康体检的老年人50例（对照组）,测定其第一秒用力呼气容积（FEV1）、用力肺活量（FVC）和圣乔治呼吸问卷（SGRQ）评分.用ELISA法检测Cpn抗体（IgA,IgG和IgM）.结果 COPD急性加重期患者的Cpn-IgM抗体检出率显著高于对照组（P＜0.01）,COPD急性加重期组和COPD稳定期组Cpn-IgA和IgG抗体的检出率均显著高于对照组（P＜0.01）.阿奇霉素治疗后所有COPD患者的临床症状均有显著改善：SGRQ记分和FEV1占预计值％显著增加,仅COPD急性加重期患者Cpn-IgM滴度显著下降（P＜0.01）.结论 慢性Cpn感染可能是COPD发展的危险因素.     

外周血炎症介质水平对COPD疾病状态的预测价值

目的通过测定外周血炎症介质水平探讨其在COPD不同疾病状态的预测价值。方法测定AECOPD患者治疗前、治疗后、出院后12 wk及稳定期患者血清TNF-α、CRP水平及肺功能（FEV1%）,对各组参数分析。结果 AECOPD患者治疗前血清CRP、TNF-a水平显著高于治疗后、出院后12周及COPD稳定期水平,治疗后血清CRP、TNF-a水平显著高于12周和COPD稳定期水平（P〈0.05）,而后两者无显著性差异（P〉0.05）。COPD急性加重期治疗前FEV1%水平显著低于各组FEV1%水平（P〈0.05）。CRP与TNF-a呈显著正相关（r=0.848,P〈0.01）,CRP与FEV1%呈显著负相关（r=-0.710,P〈0.01）,TNF-α与FEV1%呈显著负相关（r=-0.771,P〈0.01）。结论血清TNF-α和CRP水平对预测AECOPD患者疾病的严重程度有帮助,测定血清TNF-α、CRP水平可以反映肺功能损害程度。     

慢性阻塞性肺疾病与冠状动脉粥样硬化的相关性分析

目的分析冠状动脉粥样硬化患者与冠状动脉粥样硬化合并COPD患者外周血液指标、肺功能、Gensini评分的差异性,探讨cOPD对冠状动脉粥样硬化的影响。方法通过冠状动脉造影和肺功能检查,将62例研究对象分为正常对照组16例、冠状动脉粥样硬化组20例,冠状动脉粥样硬化合并COPD组26例。记录所有研究对象外周血白细胞、中性粒细胞、单核细胞、淋巴细胞、血小板计数,血清总胆固醇、甘油三脂、高密度脂蛋白、低密度脂蛋白、ApoA—I、ApoB,血浆纤维蛋白原（Fbg）,空腹血糖、肺功能（FEV1％pred、FEV1/FVC比值）及冠状动脉造影术后Gensini评分。按COPD的严重程度分为轻度6例、中度16例、重度以上4例。应用SPSS17．0统计软件,分析冠状动脉粥样硬化合并COPD组与冠状动脉粥样硬化组血液指标及FEV1％pred的差异性;分析Gensini评分在两组间的差异性及与FEV1％pred、血液指标、COPD严重程度的相关性。逐步回归分析上述指标对Gensini评分的影响。结果与正常对照组比较,冠状动脉粥样硬化组及冠状动脉粥样硬化合并COPD组外周血白细胞、中性粒细胞计数明显升高,且差异有统计学意义（P〈0．05）,FEV1％pred均明显降低,且差异有统计学意义（P〈0．05）。冠状动脉粥样硬化合并COPD组与冠状动脉粥样硬化组比较,外周血白细胞、中性粒细胞、单核细胞计数均明显升高,差异有统计学意义（P〈0．05）,FEV1％pred显著降低（P〈0．05）,Gensini评分明显升高（P〈0．05）。冠状动脉粥样硬化合并COPD组,Gensini评分与白细胞计数（r=0．438,P〈0．05）及单核细胞计数（r=0．421,P〈0．05）呈正相关性;Gensini评分与FEV1％pred呈负相关性（r=0．668,P〈0．05）。多元回归分析仅FEV1％pred与Gensini评分具有独立相关性,（Y=83．535—0．675×FEV1％pred）。结论COPD患者的气流受限是冠状动脉粥样硬化的危险因素,可能与COPD的炎症反应加重冠状动脉粥样硬化有关。     

慢性阻塞性肺疾病患者诱导痰中α-防御素1—3含量与病情程度的相关性研究

目的探讨慢性阻塞性肺疾病急性加重期（AECOPD）患者治疗前后诱导痰中α-防御素1-3（HNP1—3）含量、中性粒细胞比例（N％）与肺功能及血气分析结果的相关性,以探讨HNP1—3在COPD发病机制中的可能作用。方法收集AECOPD患者42例（根据肺功能检测结果分为轻度组11例、中度组13例、重度组18例）治疗前后及20例急性支气管炎痊愈者（对照组）的诱导痰,分别进行痰中性粒细胞计数并计算其百分比,用ELISA方法检测诱导痰中HNP1—3的含量;测定各观察对象治疗前后的血气分析及肺功能,分析HNP1—3含量与N％、肺功能和血气分析的相关性。结果COPD患者诱导痰中HNP1-3水平、N％、PaCO2随病情严重程度的增加而增高（P〈0．01）,并明显高于对照组（P〈0．01）,FEV,％pred、FEV,／FVC、PaO2随病情严重程度的增加而降低（P〈0．01）,明显低于对照组（P〈0．01）。三组患者诱导痰中HNP1—3含量分别与N％呈显著正相关（r=0．887～0．973,P值均〈0．01）,与FEV,Yoopred、FEV,／FVC、Pa02分别呈显著负相关（r=0．721～0．973,P值均〈0．01）。经治疗一周后,轻度、中度、重度患者FEV,Voopred、FEV1／FVC、PaO2明显增高,诱导痰中HNP1—3含量、N％明显降低。结论HNPl—3参与了COPD炎症的过程,此过程与中性粒细胞有关。痰中HNPl3含量可作为COPD患者病情严重程度的指标,并有助于判断预后。     

COPD患者血浆IL-17、sICAM-1的研究

目的探讨慢性阻塞性肺疾病（COPD）患者血浆白细胞介素-17（IL-17）、可溶性细胞间粘附分子-1（sICAM-1）浓度的变化及相关性。方法30例急性加重期和稳定期COPD患者、25例健康体检者,分别查血常规、测定肺功能,用ELISA法检测血浆IL-17、sICAM-1浓度。结果同一患者COPD急性加重期血浆IL-17浓度、sICAM-1浓度均明显高于稳定期（P〈0.01,P〈0.01）;患者COPD急性加重期血浆IL-17浓度、sICAM-1浓度明显高于健康对照组（P〈0.01,P〈0.01）,患者COPD稳定期血浆IL-17浓度、sICAM-1浓度明显高于健康对照组（P〈0.01,P〈0.01）且在急性加重期IL-17、sICAM-1与Neu／Leu％呈正相关（r=0.824,P〈0.01;r=0.827,P〈0.01）。结论COPD急性加重期及稳定期IL-17、sICAM-1水平显著升高,提示IL-17、sICAM-1参与了COPD的发病,可能是引起肺内炎症细胞浸润及肺实质破坏的主要原因之一。     

慢性阻塞性肺疾病急性加重期血清MMP-9、TIMP-1变化的临床意义

目的探讨慢性阻塞性肺疾病（COPD）急性加重期血清基质金属蛋白酶-9（MMP-9）、基质金属蛋白酶组织抑制剂-1（TIMP-1）变化的临床意义。方法选取COPD急性加重期患者55例（COPD组）、查体健康者20例（对照组）,根据COPD组肺功能及病情程度分为轻度组15例、中度组22例、重度组18例。采用酶联免疫吸附法检测各组血清MMP-9及TIMP-1;行肺功能通气检查,记录第1秒钟用力呼吸容积（FEV1）/用力肺活量（FVC）及FEV1占预计值的百分比（FEV1%）。分析COPD组血清MMP-9、TIMP-1水平与病情严重程度的相关性。结果 COPD组血清MMP-9、TIMP-1明显高于对照组,且随病情加重逐渐升高（P〈0.01或〈0.05）;直线相关分析显示,COPD组血清MMP-9、TIMP-1水平与FEV1%呈负相关（r分别为-0.783、-0.776,P均〈0.01）。结论血清MMP-9、TIMP-1水平与COPD病情程度相关,病情越重,MMP-9、TIMP-1越高,且与FEV1%呈负相关;提示血清MMP-9、TIMP-1变化可作为判定COPD病情严重程度的指标之一。     

慢性阻塞性肺疾病患者血清Fas／Apo-1及TNF-α与细胞凋亡的相关性研究

目的探讨慢性阻塞性肺疾病（COPD）患者血清可溶性（Fas）及（TNF-α）的变化及相关性。方法30例急性加重期和稳定期COPD患者、25例健康体检者，分别查血常规、测定肺功能，用EHSA法检测血清sFas及TNF-α浓度。结果发现COPD急性加重期组患者外周血中性粒细胞占白细胞总数百分比Neu／Leu％、sFas、TNF-α明显高于COPD稳定期组（P〈0．01，P〈0．05，P〈0．01）；COPD急性加重期组患者血清sFas、TNF-α明显高于健康对照组（P〈0．05，P〈0．01），且在急性加重期组中TNF-α与Neu／Leu％呈正相关（r=0．586，P〈0．05）。结论COPD急性加重期及稳定期sFas和TNF-α水平显著升高，提示凋亡参与了COPD的发病，可能是引起肺内炎症细胞浸润及肺实质破坏的主要原因之一。     

Urinary excretion of leukotriene E4 and eosinophil protein X in children with atopic asthma.

Measurement of leukotriene E4 (LTE4) in urine is a noninvasive method for assessing changes in the rate of total body cysteinyl leukotriene production. Eosinophil protein X (EPX) has been used to assess eosinophil activity and monitor inflammation in bronchial asthma. The aim of the study was to look for differences in urinary LTE4 and EPX concentrations between children with stable atopic asthma and healthy controls and to compare asthmatic children with different disease severity. In addition the relationship was evaluated between urinary LTE4 and EPX levels and lung function. LTE4 was also measured (enzyme immunoassay) together with EPX (radioimmunoassay) in urine and lung function tests were carried out in children with mild asthma (steroid-naive) (n=49), moderate to severe asthma (using inhaled steroids) (n=31) and healthy control subjects (n=28). Urinary leukotriene E4 (LTE4) was significantly higher in children with asthma than in controls (median [25-75 percentile] 238.5 (126.5-375.7) SD 191.8 versus 189 (51-253.2) SD 131.7 pg.mg(-1) creatinine; p=0.021). Urinary EPX was also significantly increased in asthmatic children compared with controls (85.5 [64-131.5] SD 76.2 versus 48.5 [43.2-90] 112.1 microg x mmol(-1) creatinine; p=0.006). There were no differences in urinary LTE4 and EPX between the group of mild and the group of moderate to severe asthmatic children. There were significant associations between the urinary LTE4 and intrathoracic gas volume (ITGV), residual volume (RV), forced expiratory volume in one second (FEV1), forced expiratory capacity (FVC) and maximum expiratory flow rate at 25% of vital capacity (MEF25). Urinary EPX was only correlated with maximum expiratory flow rate at 75% of vital capacity (MEF75). Thus measurement of urinary LTE4 may predict the degree of airflow obstruction in asthmatic children. Urinary LTE4 and EPX are useful markers of airway inflammation and can be helpful in guiding asthma management. There was no correlation between LTE4 and EPX levels.     

Urinary leukotriene E4 in bronchial asthma.

Leukotriene E4 (LTE4) is excreted into the urine in a relatively constant proportion of 4-7% when either leukotriene C4 (LTC4) or LTE4 is intravenously infused, regardless of the magnitude of the infused dose. Measurement of LTE4 in urine is, therefore, a convenient and non-invasive method for assessing changes in the rate of total body sulphidopeptide leukotriene production. We assayed urinary LTE4 in 17 normal subjects, 31 subjects with asthma without aspirin sensitivity, and 10 aspirin-sensitive subjects. The relationship between urinary LTE4 and nonspecific bronchial hyperresponsiveness, as assessed by the provocative dose producing a 20% fall in forced expiratory volume in one second (PD20) to inhaled histamine, was examined in 19 non-aspirin-sensitive asthmatic subjects. The urinary LTE4 values were log-normally distributed. Urinary LTE4 was detected in 28 of the 31 non-aspirin-sensitive asthmatic subjects, and the geometric mean (95% confidence interval (CI) of 43 (32-57) pg.mg-1 creatinine was no different to that of 34 (25-48) pg.mg-1 creatinine measured in the normal subjects. The geometric mean of 101 (55-186) pg.mg-1 creatinine measured in the aspirin-sensitive asthmatics was significantly higher than that measured in the normal subjects (p less than 0.005) and in the asthmatic subjects who were non-aspirin-sensitive (p less than 0.002), but there was considerable overlap between the three groups. There was no relationship between urinary LTE4 and PD20, or between urinary LTE4 and baseline forced expiratory volume in one second (FEV1) (% predicted). Thus, measurement of LTE4 in a single sample of urine will not predict the extent of bronchial hyperresponsiveness or degree of airflow obstruction.     

Diagnosis of upper airway obstruction by pulmonary function testing.

We compared 11 patients with upper airway obstruction (obstruction at or proximal to the carina) to 22 patients with chronic obstructive pulmonary disease and to 15 normal subjects utilizing spirometry, lung volumes, airway resistance, maximal voluntary ventilation, single-breath diffusion capacity, and maximal inspiratory and expiratory flow-volume loops. Four values usually distinguished patients with upper airway obstruction: (1) forced inspiratory flow at 50 percent of the vital capacity (FIF50%) less than or equal to 100 L/min; (2) ratio of forced expiratory flow at 50 percent of the vital capacity of the FIR50% (FEF50%/FIF50%) larger than or equal to 1; (3) ratio of the forced expiratory volume in one second measured in milliliters to the peak expiratory flow rate in liters per minute (FEV1/PEFR) larger than or equal to 10 ml/L/min; and (4) ratio of the forced expired volume in one second to the forced expired volume in 0.5 second (FEV1/FEV0.5) larger than or equal to 1.5. The last ratio can be determined with a simple spirometer.     

Comparison of two standardized methods of methacholine inhalation challenge in young adults.

In the European Community Respiratory Health Study (ECRHS), airway responsiveness to methacholine was determined using the Mefar dosimeter protocol. Elsewhere, the 2-min tidal breathing method has become the preferred standardized method. The relationship between measurements of responsiveness by these two methods is not well established. This study measured airway responsiveness to methacholine by dosimeter and tidal breathing methods in 47 healthy asthmatic subjects aged 20-44 yrs. Tests were performed within 1 week and in random order. Baseline forced expiratory volume in one second (FEV1) varied by <10% between tests in 42/47 subjects. There was a close association between responsiveness determined by the two methods. A provocative concentration of methacholine causing a 20% fall in FEV1 (PC20) value of < or =8.0 mg x mL(-1) (tidal method) used to categorize airway hyperresponsiveness agreed most closely with a provocative dose of methacholine causing a 20% fall in FEV1 (PD20) value of < or =0.5 mg (dosimeter method) (kappa statistic 0.78). Each doubling or halving of PC20 to define a level of hyperresponsiveness agreed closely with a doubling or halving of PD20. Assessment of airway responsiveness as provocative dose of methacholine causing a 20% fall in forced expiratory volume in one second by the Mefar dosimeter protocol gave a close and predictable relationship with provocative concentration of methacholine causing a 20% fall in expiratory volume in one second assessed using the tidal breathing method. Airway hyperresponsiveness as determined by the accepted criterion of provocative concentration of methacholine causing a 20% fall in expiratory volume in one second < or =8 mg x mL(-1) was best correlated with provocative dose of methacholine causing a 20% fall in forced expiratory volume in one second <0.5 mg by Mefar dosimeter.     

Can urinary eicosanoids be a potential predictive marker of clinical response to thromboxane A2 receptor antagonist in asthmatic patients?

Thromboxane (TX) A2 is an important bronchoconstrictor in the pathogenesis of asthma. Seratrodast, known as AA-2414, is a new oral TXA2 receptor antagonist which is currently prescribed in asthma therapy in Japan. However its clinical effects have been very different in individual subjects. To assess whether the clinical efficacy of TXA2 antagonist is predictable on the basis of urinary arachidonic acid metabolites in urine of patients with asthma, an open and multicentre trial was conducted. Fifty adult asthmatic subjects (women/men = 28/22) were enrolled [resting mean forced expiratory volume in 1 sec (FEV1)% was 82%; range, 50-96%]. Urinary levels of 11-dehydro-TXB2, leukotriene (LT) E4, 2,3-dinor-6-keto-prostaglandin F1alpha and creatinine in 3-h urine collected in the morning at the start of seratrodast (80 mg day(-1), once a day at evening for 4 weeks) were measured. Responders were defined by improvements of asthma symptoms score and peak expiratory flow rate (PEFR). Of the 50 subjects, 45 completed this study. Eighteen patients were responders and the other 27 were nonresponders. There were no significant differences between the two groups in patients' characteristics, baseline lung functions, treatments and baseline urinary eicosanoids. The 11-dehydro-TXB2/LTE4 ratio of responders was significantly higher (P = 0.0091) than that of non-responders (mean +/- SE, 7.49+/-0.71 vs. 5.09+/-0.67). Eleven patients out of 18 responders agreed to continue this drug for 6 months, the 11-dehydro-TXB2/LTE4 ratio decreased during this period, but not significantly. Our data demonstrated that responders and non-responders to TXA2 receptor antagonist existed in patients with asthma, and it suggests that the ratio of urinary eicosanoids might be a possible predictor of the effects of TXA2 receptor antagonist.     

Lung Function in Young Adults Predicts Airflow Obstruction 20 Years Later

Objective

The burden of obstructive lung disease is increasing, yet there are limited data on its natural history in young adults. To determine in a prospective cohort of generally healthy young adults the influence of early adult lung function on the presence of airflow obstruction in middle age.

Methods

A longitudinal study was performed of 2496 adults who were 18 to 30 years of age at entry, did not report having asthma, and returned at year 20. Airflow obstruction was defined as an forced expiratory volume in 1 second/forced vital capacity ratio less than the lower limit of normal.

Results

Airflow obstruction was present in 6.9% and 7.8% of participants at years 0 and 20, respectively. Less than 10% of participants with airflow obstruction self-reported chronic obstructive pulmonary disease. In cross-sectional analyses, airflow obstruction was associated with less education, smoking, and self-reported chronic obstructive pulmonary disease. Low forced expiratory volume in 1 second, forced expiratory volume in 1 second/forced vital capacity ratio, and airflow obstruction in young adults were associated with low lung function and airflow obstruction 20 years later. Of those with airflow obstruction at year 0, 52% had airflow obstruction 20 years later. The forced expiratory volume in 1 second/forced vital capacity at year 0 was highly predictive of airflow obstruction 20 years later (c-statistic 0.91; 95% confidence interval, 0.89-0.93). The effect of cigarette smoking on lung function decline with age was most evident in young adults with preexisting airflow obstruction.

Conclusion

Airflow obstruction is mostly unrecognized in young and middle-aged adults. Low forced expiratory volume in 1 second, low forced expiratory volume in 1 second/forced vital capacity ratio, airflow obstruction in young adults, and smoking are highly predictive of low lung function and airflow obstruction in middle age.     

Preoperative and postoperative pulmonary function tests in patients with atrial septal defect and their relation to pulmonary artery pressure and pulmonary:systemic flow ratio.

Pulmonary diffusing properties and lung volumes were investigated in 44 patients with atrial septal defect, and in 30 of them preoperative and postoperative data were obtained. The patients were divided into three groups according to mean pulmonary artery pressure: less than or equal to 15 mm Hg (group 1), 16-29 mm Hg (group 2), and greater than or equal to 30 mm Hg (group 3). Patients in groups 1 and 2 had a high carbon monoxide transfer test which became normal after surgical correction of their septal defect. In group 3, the carbon monoxide transfer test was normal both before and after operation. As mean pulmonary artery pressure increased there was a progressive reduction in both forced expiratory volume in one second and vital capacity. Patients in group 3 had a low forced expiratory volume in one second, a low vital capacity, and a reduced forced expiratory volume in one second:vital capacity ratio. These abnormalities were not corrected by surgical closure of the septal defect. Formulas were derived from the lung function data, to predict the mean pulmonary artery pressure and the pulmonary:systemic flow ratio. The values predicted when these two formulas were applied to data obtained for patients in this study correlated well with measured values.     

Reduced intracellular magnesium concentrations in asthmatic patients.

Magnesium is important in the regulation of bronchomotor tone, and low dietary intake of magnesium has been associated with airway hyperresponsiveness in epidemiological studies. The concentration of magnesium in serum, erythrocytes and urine in 49 patients with asthma (29 males, aged 15-65 yrs) and in 25 normal subjects (15 males, aged 17-36 yrs) was studied by atomic absorption. Magnesium concentrations were significantly lower in erythrocytes and urine in both atopic (n = 26) and nonatopic (n = 23) asthmatic patients as compared with the control group, whereas serum concentrations did not differ. The concentration of magnesium in erythrocytes was not related to the degree of airway obstruction as measured by forced expiratory volume in one second (FEV1) but was significantly correlated with airway hyperresponsiveness measured as the provocative concentration causing a 20% fall in FEV1 to inhaled acetylcholine (r = 0.64; p<0.05). In addition, a magnesium tolerance test showed increased retention of magnesium (58.9% of administered dose in asthmatic patients compared with 8.9% in normal subjects, p<0.05). In conclusion, the low cellular concentration of magnesium may be associated with airway hyperresponsiveness in asthmatic patients.     

Preoperative and postoperative pulmonary function tests in patients with atrial septal defect and their relation to pulmonary artery pressure and pulmonary:systemic flow ratio

Pulmonary diffusing properties and lung volumes were investigated in 44 patients with atrial septal defect, and in 30 of them preoperative and postoperative data were obtained. The patients were divided into three groups according to mean pulmonary artery pressure: less than or equal to 15 mm Hg (group 1), 16-29 mm Hg (group 2), and greater than or equal to 30 mm Hg (group 3). Patients in groups 1 and 2 had a high carbon monoxide transfer test which became normal after surgical correction of their septal defect. In group 3, the carbon monoxide transfer test was normal both before and after operation. As mean pulmonary artery pressure increased there was a progressive reduction in both forced expiratory volume in one second and vital capacity. Patients in group 3 had a low forced expiratory volume in one second, a low vital capacity, and a reduced forced expiratory volume in one second:vital capacity ratio. These abnormalities were not corrected by surgical closure of the septal defect. Formulas were derived from the lung function data, to predict the mean pulmonary artery pressure and the pulmonary:systemic flow ratio. The values predicted when these two formulas were applied to data obtained for patients in this study correlated well with measured values.     

Expiratory flow limitation and obstruction in the elderly.

Elderly people commonly suffer from dyspnoea, which may stem from expiratory flow limitation (EFL). The relationship between EFL, as assessed by the negative expiratory pressure method and spirometric indices, was investigated in an elderly French population. Subjects, aged 66-88 yrs, filled in socio-demographic and standardised questionnaires, which dealt with: medical history, smoking status and respiratory symptoms. EFL measurements and forced expiratory manoeuvres were performed. Validated measurements were obtained in 750 out of 1,318 subjects: 47% were EFL+ (EFL >0), with a higher prevalence in females than in males. EFL and forced expiratory volume in one second (FEV1) were correlated with age. A total of 116, from the 750 subjects, with no medical history and no symptoms, served as a healthy group. The prevalence of EFL+ subjects increased with the grade of dyspnoea and was highest in respiratory and cardiac patients when compared with the healthy subjects. EFL did not correlate with FEV1/forced vital capacity (FVC), the usual index of obstruction. Some elderly subjects (15%) with dyspnoea but with no medical history, mainly females with small FVC and normal FEV1/FVC, had a greater EFL than the healthy subjects. In elderly people, expiratory flow limitation measurements, along with the usual forced expiratory volume in one second/ forced vital capacity ratio, may be of value for the interpretation of dyspnoea.