Publications by authors named "Volker Unger"

Background: Particulate matter (PM) is assumed to exert a major burden on public health. Most studies that address levels of PM use stationary measure systems. By contrast, only few studies measure PM concentrations under mobile conditions to analyze individual exposure situations.

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Due to an increasing awareness of the potential hazardousness of air pollutants, new laws, rules and guidelines have recently been implemented globally. In this respect, numerous studies have addressed traffic-related exposure to particulate matter using stationary technology so far. By contrast, only few studies used the advanced technology of mobile exposure analysis.

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Introduction: Models of isolated and perfused lungs study pathophysiological phenomena of the airways, but are limited by restricted resemblance to the human situation, non-physiological perfusates or the need for the use of high numbers of laboratory animals. The present model was established to address these difficulties.

Objectives: Aim of the current study was the establishment of an animal model that uses slaughterhouse animals and closely resembles physiological conditions found in humans.

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Background: Models of isolated and perfused kidneys are used to study the effects of drugs, hazardous or toxic substances on renal functions. Since physiological and morphological parameters of small laboratory animal kidneys are difficult to compare to human renal parameters, porcine kidney perfusion models have been developed to simulate closer conditions to the human situation, but exact values of renal parameters for different collection and perfusion conditions have not been reported so far. If the organs could be used out of regular slaughtering processes animal experiments may be avoided.

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Isolated porcine kidneys are commonly used to study physiological and pathophysiological aspects of renal homeostasis but standardized evaluation procedures of renal function in this model do not exist so far. A double-logarithmical nomogram is established for filtration and reabsorption functions in isolated and hemoperfused porcine kidneys using different perfusion settings. Model validity was demonstrated by the levels of urine flow and sodium excretion showing expected alteration levels of lowering in the ADH-group and increasing in the furosemide-group of isolated kidneys.

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Polidocanol is an effective sclerosing agent that consists of 95% hydroxypolyethoxydodecane and 5% ethyl alcohol and is known to have a low risk of complications. However, since the compound has been proposed for the local treatment of liver diseases, the potential for topical hepatic side effects should be examined. Therefore, the new model of normothermic-hemoperfused isolated porcine slaughterhouse livers was used to examine polidocanol-hepatotoxicity encompassing the advantages of slaughterhouse organs to reduce animal experiments and autologous blood as an optimal perfusate.

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Reperfusion injuries after organ transplantation affect graft function and influence long-term graft survival. As hypothermic storage, which minimizes the extent of unspecific tissue injury after ischemia and reperfusion, is significantly influenced by the composition of preservation solutions, strategies to optimize the different components may lead to longer graft survival. In the present study the effects of the preservation solution B2 on early renal function and histopathological changes were compared to histidine-tryptophan-ketoglutarate solution (HTK, Bretschneider) in a model of isolated blood-perfused porcine kidneys.

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Background: The isolated perfused canine kidney has been established as a valid model for conducting both renal physiology and transplantation research. This model is of particular importance for developing new strategies to improve graft function after renal transplantation. In the present study, a newly developed method using isolated haemoperfused porcine kidneys was adapted for use in canine kidneys.

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Mammalian models of isolated perfused kidneys provide an important tool to study pharmacological, toxicological, and physiological properties of drugs, hormones, and vasoactive substances. As organs from small laboratory animals are difficult to compare to human conditions, porcine and bovine kidneys permit better approaches to simulate human conditions. We developed an alternative model for pharmacological studies using isolated hemoperfused porcine kidneys from slaughterhouse animals to reduce laboratory animal experiments.

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Different models of isolated and perfused livers and precision cut liver slices have been developed for studies on liver toxicology the past years. As most of these models were limited by nonphysiologic settings, a new model of normothermic hemoperfused isolated porcine slaughterhouse livers to examine hepatotoxicity was established encompassing the advantages of slaughterhouse organs to reduce animal experiments and autologous blood as an optimal perfusate. As model compound, the analgesic substance diclofenac was used and the effects of this drug on organ function parameters were compared to an untreated control group.

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Background: The rapidly evolving field of transplantation research with a focus on ischemic and reperfusion injuries has gained importance since the methodology of organ preservation significantly limits graft survival. Numerous models of isolated perfused kidneys have been established in the past years but limitations such as organ size, perfusate and ethical standards have restricted a widespread research in this area.

Methods: A model of hemoperfused isolated porcine slaughterhouse kidneys was established which encompasses the advantages of autologous blood as optimal perfusate and a reduction of animal experiments.

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