Karl-Heinz Krause

Bio: Karl-Heinz Krause is an academic researcher from University of Geneva. The author has contributed to research in topics: NADPH oxidase & Embryonic stem cell. The author has an hindex of 83, co-authored 296 publications receiving 28050 citations. Previous affiliations of Karl-Heinz Krause include Vita-Salute San Raffaele University & University of Padua.

The NOX Family of ROS-Generating NADPH Oxidases: Physiology and Pathophysiology

Abstract: For a long time, superoxide generation by an NADPH oxidase was considered as an oddity only found in professional phagocytes. Over the last years, six homologs of the cytochrome subunit of the phag...

Ageing and infection

Abstract: Average life expectancy throughout developed countries has rapidly increased during the latter half of the 20th century and geriatric infectious diseases have become an increasingly important issue. Infections in the elderly are not only more frequent and more severe, but they also have distinct features with respect to clinical presentation, laboratory results, microbial epidemiology, treatment, and infection control. Reasons for increased susceptibility include epidemiological elements, immunosenescence, and malnutrition, as well as a large number of age-associated physiological and anatomical alterations. Moreover, ageing may be the cause of infection but infection can also be the cause of ageing. Mechanisms may include enhanced inflammation, pathogen-dependent tissue destruction, or accelerated cellular ageing through increased turnover. In most instances, treatment of infection leads to a satisfactory outcome in the elderly. However, in palliative care situations and in patients with terminal dementia, the decision whether or not to treat an infectious disease is becoming a difficult ethical issue.

Reactive oxygen species: from health to disease.

Abstract: Upon reaction with electrons, oxygen is transformed into reactive oxygen species (ROS). It has long been known that ROS can destroy bacteria and destroy human cells, but research in recent decades has highlighted new roles for ROS in health and disease. Indeed, while prolonged exposure to high ROS concentrations may lead to non-specific damage to proteins, lipids, and nucleic acids, low to intermediate ROS concentrations exert their effects rather through regulation of cell signalling cascades. Biological specificity is achieved through the amount, duration, and localisation of ROS production. ROS have crucial roles in normal physiological processes, such as through redox regulation of protein phosphorylation, ion channels, and transcription factors. ROS are also required for biosynthetic processes, including thyroid hormone production and crosslinking of extracellular matrix. There are multiple sources of ROS, including NADPH oxidase enzymes; similarly, there are a large number of ROS-degrading systems. ROS-related disease can be either due to a lack of ROS (e.g., chronic granulomatous disease, certain autoimmune disorders) or a surplus of ROS (e.g., cardiovascular and neurodegenerative diseases). For diseases caused by a surplus of ROS, antioxidant supplementation has proven largely ineffective in clinical studies, most probably because their action is too late, too little, and too non-specific. Specific inhibition of ROS-producing enzymes is an approach more promising of clinical efficacy.

NOX4 activity is determined by mRNA levels and reveals a unique pattern of ROS generation

Abstract: NOX4 is an enigmatic member of the NOX (NADPH oxidase) family of ROS (reactive oxygen species)-generating NADPH oxidases. NOX4 has a wide tissue distribution, but the physiological function and activation mechanisms are largely unknown, and its pharmacology is poorly understood. We have generated cell lines expressing NOX4 upon tetracycline induction. Tetracycline induced a rapid increase in NOX4 mRNA (1 h) followed closely (2 h) by a release of ROS. Upon tetracycline withdrawal, NOX4 mRNA levels and ROS release decreased rapidly ( 100 muM). The pattern of NOX4-dependent ROS generation was unique: (i) ROS release upon NOX4 induction was spontaneous without need for a stimulus, and (ii) the type of ROS released from NOX4-expressing cells was H(2)O(2), whereas superoxide (O(2)(-)) was almost undetectable. Probes that allow detection of intracellular O(2)(-) generation yielded differential results: DHE (dihydroethidium) fluorescence and ACP (1-acetoxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine) ESR measurements did not detect any NOX4 signal, whereas a robust signal was observed with NBT. Thus NOX4 probably generates O(2)(-) within an intracellular compartment that is accessible to NBT (Nitro Blue Tetrazolium), but not to DHE or ACP. In conclusion, NOX4 has a distinct pharmacology and pattern of ROS generation. The close correlation between NOX4 mRNA and ROS generation might hint towards a function as an inducible NOX isoform.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

The NOX Family of ROS-Generating NADPH Oxidases: Physiology and Pathophysiology

Abstract: For a long time, superoxide generation by an NADPH oxidase was considered as an oddity only found in professional phagocytes. Over the last years, six homologs of the cytochrome subunit of the phag...

Acute Kidney Injury Network: report of an initiative to improve outcomes in acute kidney injury

Abstract: Acute kidney injury (AKI) is a complex disorder for which currently there is no accepted definition. Having a uniform standard for diagnosing and classifying AKI would enhance our ability to manage these patients. Future clinical and translational research in AKI will require collaborative networks of investigators drawn from various disciplines, dissemination of information via multidisciplinary joint conferences and publications, and improved translation of knowledge from pre-clinical research. We describe an initiative to develop uniform standards for defining and classifying AKI and to establish a forum for multidisciplinary interaction to improve care for patients with or at risk for AKI. Members representing key societies in critical care and nephrology along with additional experts in adult and pediatric AKI participated in a two day conference in Amsterdam, The Netherlands, in September 2005 and were assigned to one of three workgroups. Each group's discussions formed the basis for draft recommendations that were later refined and improved during discussion with the larger group. Dissenting opinions were also noted. The final draft recommendations were circulated to all participants and subsequently agreed upon as the consensus recommendations for this report. Participating societies endorsed the recommendations and agreed to help disseminate the results. The term AKI is proposed to represent the entire spectrum of acute renal failure. Diagnostic criteria for AKI are proposed based on acute alterations in serum creatinine or urine output. A staging system for AKI which reflects quantitative changes in serum creatinine and urine output has been developed. We describe the formation of a multidisciplinary collaborative network focused on AKI. We have proposed uniform standards for diagnosing and classifying AKI which will need to be validated in future studies. The Acute Kidney Injury Network offers a mechanism for proceeding with efforts to improve patient outcomes.