Body plethysmography--its principles and clinical use.

Body plethysmography allows to assess functional residual capacity (FRC(pleth)) and specific airway resistance (sRaw) as primary measures. In combination with deep expirations and inspirations, total lung capacity (TLC) and residual volume (RV) can be determined. Airway resistance (Raw) is calculated as the ratio of sRaw to FRC(pleth). Raw is a measure of airway obstruction and indicates the alveolar pressure needed to establish a flow rate of 1 L s(-1). In contrast, sRaw can be interpreted as the work to be performed by volume displacement to establish this flow rate. These measures represent different functional aspects and should both be considered. The measurement relies on the fact that generation of airflow needs generation of pressure. Pressure generation means that a mass of air is compressed or decompressed relative to its equilibrium volume. This difference is called "shift volume". As the body box is sealed and has rigid walls, its free volume experiences the same, mirror image-like shift volume as the lung. This shift volume can be measured via the variation of box pressure. The relationship between shift volume and alveolar pressure is assessed in a shutter maneuver, by identifying mouth and alveolar pressure under zero-flow conditions. These variables are combined to obtain FRC(pleth), sRaw and Raw. This presentation aims at providing the reader with a thorough and precise but non-technical understanding of the working principle of body plethysmography. It also aims at showing that this method yields significant additional information compared to spirometry and even bears a potential for further development.

[Risk of interrupting nocturnal nasal continuous positive airway pressure (nCPAP) in patients with obstructive sleep apnea]. / Perioperative Unterbrechung der nächtlichen Uberdruckbeatmung gefährdet Schlafapnoe-Patienten.

Patients with obstructive sleep apnea are at risk of respiratory and cardiovascular complications (e.g. hypoxia, hypertensive crisis, cardiac ischemia and arrhythmias) as a result of airway callapse during the perioperative period. Therefore it is essential that the nasal continuous airway pressure (nCPAP-therapy) be maintained during that time. Such patients and the medical staff should be aware of this problem.

Extrinsic allergic alveolitis (hypersensitivity pneumonitis) caused by Sphingobacterium spiritivorum from the water reservoir of a steam iron.

A case of extrinsic allergic alveolitis (EAA) caused by Sphingobacterium spiritivorum is described. The symptoms were associated with the use of a steam iron. The water reservoir was heavily contaminated with S. spiritivorum (10(6) CFU ml(-1)). This is the first report of S. spiritivorum as a causative agent of EAA.

Claudin-4: a new target for pancreatic cancer treatment using Clostridium perfringens enterotoxin.

BACKGROUND & AIMS: Recently, several members of the claudin family have been identified as integral constituents of tight junctions. Using expression profiling, we previously found claudin-4 to be overexpressed in pancreatic cancer. Because claudin-4 has been described as a receptor for the cytotoxic Clostridium perfringens enterotoxin (CPE), we investigated the effect of CPE on pancreatic cancer cells. METHODS: Expression of claudin-4 was analyzed by Northern blots. In vitro toxicity of CPE was determined by trypan blue exclusion and the (86)Rb-release assay. The in vivo effect of CPE was studied in claudin-4-expressing nude mouse xenografts of the Panc-1 cell line. RESULTS: Expression analyses showed that claudin-4 was overexpressed in most pancreatic cancer tissues and cell lines and several other gastrointestinal tumors. CPE led to an acute dose-dependent cytotoxic effect, restricted to claudin-4-expressing cells and dependent on claudin-4 expression levels. Furthermore, transforming growth factor beta was identified as a negative modulator of both claudin-4 expression and susceptibility to CPE. In vivo, intratumoral injections of CPE in Panc-1 xenografts led to large areas of tumor cell necrosis and significant reduction of tumor growth. CONCLUSIONS: Our findings suggest that targeting claudin-4-expressing tumors with CPE represents a promising new treatment modality for pancreatic cancer and other solid tumors.

[Value of non-plethysmographic methods in determining airway resistance]. / Stellenwert nicht-plethysmographischer Methoden zur Messung des Atemwiderstandes.

To examine whether the complicated method of body plethysmography can be replaced by non-plethysmographic methods, such as oscilloresistometry (Ros), the closing pressure method (Run) or the forced expiration volume method (FEV1), the authors studied the results obtained with 247 hospitalised patients between 18 and 81 years of age suffering from, or free from, airway obstruction. Although satisfactory correlations were obtained by linear and curvilinear regression analysis, considerable differences were seen in individual patients suffering from obstructions to a higher degree. Oscilloresistometry showed at the standard value limit of the airway resistance applicable in body plethysmography (0.30 kPa/l/s) a sensitivity of 89%, whereas the specificity was only 62%. Almost identical values of sensitivity (92%) and specificity (61%) were attained by the closing pressure method only if the standard value limit was set a little higher, namely, at 0.35 kPa/l/s. FEV1, which is easiest to measure, was able to objectivate an airway obstruction in a manner comparable to that of Ros and Run; there was in fact even a closer statistical correlation between the body plethysmographic resistance mographic methods are suitable for screening examinations on account of their sensitivity. However, if the results on the examination are not in keeping with the overall clinical findings, further diagnostic clarification must be sought by performing a body plethysmographic measurement.

Peripheral neuropathies in patients with chronic obstructive pulmonary disease: a multicenter prevalence study.

To investigate the prevalence and type of peripheral neuropathies (PNP) in patients with chronic obstructive pulmonary disease (COPD), we studied lung function and blood gases, clinical signs of PNP, and neurophysiological function in 151 patients with COPD without known risk factors for PNP. Mean (SD) age was 65 (10) years, mean arterial PO2 was 59 (9) mmHg, mean ratio of forced expiratory volume in the first second to vital capacity (FEV1.0/VC) was 42 (12%). Thirty patients (20%) had clinically detectable and 6 (4%) had subclinical PNP of mild degree. Fourteen (9%) of the patients with clinically detectable PNP had symptoms due to PNP. Prevalence of PNP increased with severity of hypoxemia (p less than 0.05) and was more pronounced in the lower than in the upper limbs. Age and the degree of hypoxemia were predictors to differentiate between COPD patients with and without PNP. Although the cause of PNP in COPD patients remains unknown, our observations suggest that chronic hypoxemia may contribute to PNP.