Die Messung des absoluten Sauerstoffdruckes mit der Kammer-Pt-Elektrode in beliebigen Medien,insbesondere im Blut und Gewebe

Zusammenfassung 1. Zur Absolutmessung des Sauerstoffdruckes in beliebigen Medien wird eine neuartige membranüberzogene Kammer-Pt-Elektrode beschrieben, die nach dem Prinzip von Davies u. Brink (1942) arbeitet.2. Um über Tage konstante Eichkurven zu bekommen, muß ein bestimmtes Meßschema eingehalten werden, bei dem kontinuierliches Messen, Aufsättigungszeit und die Messung selbst in einem festgelegten zeitlichen Abstand aufeinanderfolgen.3. Die Empfindlichkeit der Elektrodenanordnung für Sauerstoff hängt von der Größe des Pt-Drahtes ab; sie betrug z.B. 1 nA/mm Hg bei einem Pt-Durchmesser von 0,5 mm.4. Die mittlere quadratische Abweichung der Einzelmessung betrug je nach benutzter Verstärkeranordnung zwischen =±1% und =±2,0%.5. Die Temperaturabhängigkeit der Eichkurve ist in verschiedenen Temperaturbereichen unterschiedlich.6. Durch Kombination einer gewöhnlichen kontinuierlich messenden Pt-Elektrode mit einer Kammer-Pt-Elektrode läßt sich die gewöhnliche Pt-Elektrode mit der Kammer-Pt-Elektrode eichen. Auf diese Art wurden absolute und kontinuierliche pO₂-Messungen, z.B. auf dem Gehirn und im Blut durchgeführt.Mit 7 TextabbildungenAusgeführt mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Capsular attachment to the distal radius for extracapsular placement of pins

Abstract The aim of this study was to evaluate the anatomy of the wrist joint capsule on the distal radius. As such the extent of the joint capsule and the limits of attachment in relation to the articular surface were determined. Furthermore, the study also determined whether there was any reflection of the capsule onto the distal radius. Fifty cadaveric specimens, preserved according to Thiel’s method, were assessed. After careful dissection the distance between the chondral line of the carpal articular surface and three defined points on each of the palmar and dorsal aspects of the radius were measured. In none of the specimens was there any variation in the course and extent of the joint capsule. Using external fixators for managing fractures of the distal radius, pins and wires can be placed subchondrally close to the articular capsule. The risk of intraarticular infection, due to pin tract infection in intraarticularly positioned pins, is very low.     

Impact of ApoB-100 expression on cognition and brain pathology in wild-type and hAPPsl mice

During their lifetime, people are commonly exposed to several vascular risk factors that may affect brain ageing and cognitive function. In the last few years, increasing evidence suggests that pathological plasma lipid profiles contribute to the pathogenesis of late-onset Alzheimer's disease. Importantly, hypercholesterolemia, especially elevated low-density lipoprotein cholesterol values, that is, increased apolipoprotein B-100 (ApoB-100) levels, represents an independent risk factor. In this study, the effects of ApoB-100 overexpression, either alone or in combination with cerebral expression of human amyloid precursor protein (hAPP), on cognitive functions and brain pathology were assessed. Our results show that ApoB-100 overexpression induces memory decline and increases cerebral lipid peroxidation and amyloid beta levels compared to those in wild-type animals. Although double-transgenic ApoBxAPP animals did not develop more distinct behavioral deficits than single-transgenic hAPP littermates, hApoB-100 expression caused additional pathophysiological features, such as high LDL and low HDL-cholesterol levels, increased lipid peroxidation, and pronounced ApoB-100 accumulation in cerebral vessels. Thus, our results indicate that ApoBxAPP mice might better reflect the situation of elderly humans than hAPPsl overexpression alone.     

Minute Ventilation During Spontaneous Breathing,High-Intensity Noninvasive Positive Pressure Ventilation and Intelligent Volume Assured Pressure Support in Hypercapnic COPD

Background: High-intensity noninvasive positive pressure ventilation (HI-NPPV) is an effective treatment option in patients with stable hypercapnic chronic obstructive pulmonary disease (COPD). However, the effect of HI-NPPV compared with spontaneous breathing (SB) on minute ventilation (MV) in patients receiving long-term treatment remains to be determined. This study compared MV during HI-NPPV and SB. In addition, the ability of intelligent volume assured pressure support (iVAPS) to increase MV to the same extent as HI-NPPV was determined. Methods: Daytime pneumotachographic measurements were performed during SB, HI-NPPV and iVAPS. Results: Twenty-seven stable hypercapnic COPD patients (mean FEV₁ 34 ± 15% predicted) who had been treated with HI-NPPV for a median of 22 months (interquartile range 8.5–84 months) were enrolled. Mean MV was 9.5 ± 1.7 L/min during SB and 12.1 ± 2.8 L/min during HI-NPPV, an increase of 2.5 L/min (95%?CI [1.5–3.6] p < 0.001), or 26%. MV during iVAPS was 11.7 ± 3.6 L/min, an increase of 1.8 L/min (95%CI [0.7–3.0], p = 0.003) compared with SB. There was no difference in MV between HI-NPPV and iVAPS (p = 0.25). Conclusion: Long-term HI-NPPV increased MV by an average of 26% compared with SB in stable hypercapnic COPD patients. A similar increase in MV was observed during use of iVAPS.     

Epidemiologie von Lungenkrankheiten

Diseases of the respiratory system increase with advancing age and contribute substantially to worldwide morbidity and mortality. With respect to the number of deaths pulmonary diseases constitute the third most frequent cause of death following cardiovascular diseases and neoplasms. Lower respiratory tract infections, chronic obstructive pulmonary disease, lung cancer and tuberculosis are among the top ten causes of death worldwide and asthma is globally one of the most common chronic diseases. Despite improved medical diagnostics and therapy the prevalence and morbidity have increased in recent years. Due to increased life expectation and declining morbidity the age structure of the German population will change in the coming years with the growing group of people aged 60 years or older. While diseases, such as chronic obstructive pulmonary disease, lung cancer and pneumonia predominantly affect older people, asthma and tuberculosis occur in all age groups. Worldwide, an increase in the prevalence of lung diseases is expected for the future. The healthcare costs increase disproportionally with advancing age, therefore, the demographic transition will have a decisive impact on the healthcare system.     

Isoproterenol, norepinephrine and phosphodiesterase inhibitors are blockers of the depressed fast Na+-system in ventricular muscle fibers

It is generally agreed that β-adrenergic transmitters do not influence the maximum rate of rise of action potentials of cardiac fibers with an intact fast Na⁺-system. Inhibitory effects of epinephrine have only been reported for a Mg-activated fast current [9]. Fibers with a depressed fast Na⁺-system have been studied under various experimental conditions, some of them mimicking infarct-like environments [1,5]. In some respects the depressed fast sodium-system reacts differently, e.g. recovery from inactivation [3], Ca²⁺-effects [10], TTX-influences [6] and susceptibility to antiarrhythmic drug influence [4].We have studied the influence of isoproterenol, norepinephrine and of phosphodiesterase inhibitors on the depressed fast Na⁺-system in guinea-pig papillary muscles and gained results which are completely different to those in fibers with intact fast Na⁺-system.