Hypoxia and reoxygenation increase H2O2 production in rats

To test the effect of transition from sustained hypoxia to normoxia on production of reactive oxygen species (ROS) in lungs, the authors measured hydrogen peroxide (H(2)O(2)) output in the expired air of rats breathing hypoxic, normoxic, and hyperoxic gas mixtures at the end of exposure to 72 hours of hypoxia. Twenty-one male Wistar rats (200 to 280 g) were randomly assigned to 1 of 3 groups. First two groups (experimental) were kept for 3 days in normobaric hypoxic chamber (F(1)O(2) 0.1), rats of the third group (controls) breathed air. The rats were then anesthetized, intubated, placed in the plethysmograph, and their ventilation measured. Two periods of exhaled breath condensate (EBC) collection, each lasting 1 hour, were then performed to assay H(2)O(2) output. The controls breathed during both samplings air, the first experimental group breathed during first sampling period hypoxic mixture (F(1)O(2) 0.1; SH-H measurement) and then, during second period, air (SH-H-A measurement), the second experimental group breathed first air (SH-A measurement) and then hyperoxic mixture (F(1)O(2) 1.0; SH-A-O(2) measurement). Concentration of H(2)O(2) in the EBC was assayed by chemiluminescence. H(2)O(2) production in the control group was low and similar in both measurements (20+/-10 and 13+/-5 pmol/h, mean+/-SEM). Exposure to 72 hours of hypoxia increased the H(2)O(2) production to 105+/-18 pmol/h (SH-H). Transition from hypoxia to normoxia resulted in an increase in the H(2)O(2) production (SH-A 421+/-24 pmol/h, and SH-H-A 366+/-19 pmol/h). Following transition from air breathing to hyperoxia did not affect the H(2)O(2) production (SH-A-O(2) 373+/-25 pmol/h). The results showed that sustained hypoxia and transition from sustained hypoxia to normoxia increased H(2)O(2) formation in the lungs.     

Ouabain-like compound changes rapidly on physical exercise in humans and dogs: effects of beta-blockade and angiotensin-converting enzyme inhibition

Ouabain, an inhibitor of the sodium pump, has been identified as a constituent of bovine adrenal glands. We were interested whether the release of this cardiotonic steroid is stimulated by physical exercise. Hence, athletes and healthy dogs were subjected to ergometry. Ouabain-like compound (OLC) was measured in venous blood by enzyme-linked immunosorbent assay as well as by (86)Rb+ uptake inhibition (as ouabain equivalents). OLC increased in venous blood of athletes after 15 minutes of ergometry from 2.5+/-0.5 to 86.0+/-27.2 nmol/L (n=51; P<0.001), as did the concentration of a circulating inhibitor of the sodium pump from 7.3+/-1.7 to 129.8+/-51 nmol/L (ouabain equivalents, P<0.05). Half-maximal increase in heart rate and systolic blood pressure occurred at 5.1+/-1.2 nmol/L and at 30+/-1 nmol/L OLC, respectively. On rest, OLC decreased in humans and dogs with a half-life of 3 to 5 minutes. In beagles exposed to moderate exercise on a treadmill for 13 minutes, levels of OLC increased 46-fold (from 3.7+/-0.8 to 166.9+/-91.8 nmol/L; n=6; P<0.005). This effect was suppressed when the dogs had been treated for 3 weeks with the beta1-adrenergic receptor blocker atenolol or the angiotensin-converting enzyme inhibitor benazepril. We conclude that OLC changes rapidly during exercise and is under the control of norepinephrine and angiotensin II.     

Anesthesia for geriatric patients. Part 1: age, organ function and typical diseases

Due to demographic changes in the population of industrial nations the number of elderly patients undergoing elective or emergency procedures will rise significantly in the coming years. Anesthesia for geriatric patients is challenging for the anesthesiologist in many ways: with increasing age numerous physiological changes occur which all lead to a subsequent reduction of physical performance and compensatory capacity of the organism, in many cases additionally aggravated by chronic illness. Subsequently, these age-dependent changes (with or without chronic illness) increase the risk for admission to intensive care units, perioperative death, treatment costs and a prolonged length of hospital stay. Therefore, subtle preoperative assessment and tailored anesthetic management are essential in elderly patients. Part 1 of this continuous education article covers the influence of age on organ functions and describes typical comorbidities which are of high relevance for the perioperative care of geriatric patients. The special features of anesthetic agents and anesthesia management in the elderly will be presented in part 2.     

Moderne Steintherapie

Background

Treatment of urolithiasis saw major changes with the introduction of extracorporeal shock wave lithotripsy (ESWL) and percutaneous and ureteroscopic techniques in the 1980s. Since then these minimally invasive treatment modalities have continuously been developed further.

Results

For years ESWL has been the treatment of choice. However, recent years have seen a significant shift towards endoscopic therapies. This can be attributed to the evolving surgical experience in the use of these techniques, but even more to major improvement in the technical equipment. This trend is not backed sufficiently by high-level data (RCTs). Some of the newer data on endoscopic techniques are presented in cohort studies, but most studies are case series. Accordingly, recommendations of the German and international guidelines still focus on ESWL as first-line therapy for most locations and sizes of urinary stones.

Conclusion

The analysis of treatment data of our institution confirms these trends and demonstrates high treatment efficiency in modern stone management and a consecutive significant lowering of socio-clinical expenses.