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Biomedical subjects

U Arndt

Publications and source records attributed to U Arndt.

16 recordsLinked to original sources
PubMed2004

Correction of iron-deficient erythropoiesis in the treatment of anemia of chronic disease with recombinant human erythropoietin.

Anemia of chronic disease (ACD) is a frequent complication of chronic inflammation in rheumatoid arthritis (RA). Recombinant human erythropoietin (rHuEpo) has been shown to be effective in correcting ACD, although with a variable rate of nonresponders. The first aim of this trial was to improve the response to rHuEpo by parenteral iron supplementation in cases of iron-deficient erythropoiesis (IDE). An additional goal was the evaluation of the zinc protoporphyrin content of erythrocytes (ZnPP), the soluble transferrin receptor (sTrfR) serum concentration, and the hemoglobin (Hb) content of reticulocytes (CHr) in stimulated erythropoiesis as diagnostic and prognostic parameters. Thirty RA patients with ACD were treated with subcutaneous 150 IU rHuEpo/kg body weight twice weekly. Intravenous iron supplementation (200 mg iron sucrose once weekly) was added in cases of IDE (n=23), which was defined by the presence of two of three criteria: saturation of transferrin (TrfS) < or =15%, hypochromic erythrocytes (HypoE) > or =10%, and a serum ferritin (Fn) concentration < or =50 microg/l. All 28 completers met the treatment goal, with an increase of the median Hb concentration from 10.3 g/dl to 13.3 g/dl. Epo treatment and iron supplementation was safe and well tolerated in all patients. Monitoring of Fn, TrfS, and HypoE every other week allowed a successful correction of anemia. Retrospective analysis of the evaluable parameters (CHr, sTrfR, and ZnPP) revealed no additional benefit for predicting or monitoring IDE in this setting, although the one or other may be advantageous in other therapeutic situations.

Adult↗
PubMed2004

[Public health management in invasive meningococcal diseases].

At the 54(th) Scientific Congress of the German Professional Association of Public Health Service Physicians and Dentists in Marburg on 6th May 2004 the working group on meningococci (Arbeitsgemeinschaft Meningokokken, AGMK) organised the international workshop "Public Health Management of invasive Meningococcal Disease". In recent years significant changes in the epidemiology of meningococcal disease took place in Europe: in some countries and regions the number of disease caused by meningococci serogroup C has increased significantly. In the Netherlands this increase led to the introduction of an immunisation programme with conjugated meningococcal vaccines targeting children aged 1 up to 18 years. In Switzerland a peak in the number of reported meningococcal group C cases could be observed in some regions. Therefore, a regional vaccination programme has been introduced. Nevertheless, compared with Germany, the indications for vaccination against meningococci in Switzerland are more extensive. In the workshop, Professor Ulrich Vogel and Dr. Ingrid Ehrhard presented the epidemiological situation in Germany and the recommended prophylaxis regimen against meningococci.

Adolescent↗
PubMed2003

[Drug therapy of rheumatoid arthritis].

Nowadays undisputed is the effectiveness of early and long-standing DMARD therapy in the presence of active rheumatoid arthritis on disease progression and avoidance of structural joint changes. "Early" is defined as immediate initiation of drug therapy after diagnosis of rheumatoid arthritis. "Long-term" refers to a mostly life-long therapy, which even in the case of remission should be continued for at least 1 year. Clinical and laboratory routine controls during DMARD therapy are absolutely necessary. "DMARDs" summarize disease-modifying antirheumatic drugs such as methotrexate, sulfasalazine, leflunomide, hydroxychloroquine, aurum but also the TNF-blockers infliximab and etanercept. In cases of disease remission with combination drug therapy, corticosteroids and NSAID should be discontinued in a timely manner ahead of DMARDs to ensure that the reduction of clinical symptoms is not steroid controlled. DMARD therapy should end at least 6 months prior to conception.

Anti-Inflammatory Agents↗
PubMed1999

Assessment of the genotoxicity of mine-dump material using the Tradescantia-stamen hair (Trad-SHM) and the Tradescantia-micronucleus (Trad-MCN) bioassays.

The Tradescantia-stamen hair (Trad-SHM) and -micronucleus (Trad-MCN) bioassays were used to determine the genotoxicity of two eluates derived from mine tailings. The goal was to test the suitability of the Tradescantia bioassays as screening tools for this kind of waste material. Leachates obtained using the current standard German leaching test methods (S4 eluate) as well as leachates obtained using a new eluation method (pHstat4) were tested and compared. Concentration of heavy metals in the pHstat4 eluate were much higher than in the S4 eluate. The chemical analysis corresponded well with the results of the bioassays. Exposure to solutions containing more than 1% pHstat4 eluate caused a significantly higher number of micronuclei. The Trad-SHM bioassay also showed an increased pink mutation rate when plants were exposed to 8 or 16% eluate solutions. In contrast, the S4 eluate only caused increased mutation rates when solutions containing more than 32% eluate were used. The low pH of the pHstat4 eluate was not responsible for the genotoxicity observed using both bioassays, as indicated by the lack of significant mutation rates in the nitric acid controls. This demonstrates that the Tradescantia bioassays can be used as tools to assess the genotoxic potential of environmental samples with a wide range of pH values, without the need for sample modification.

Biological Assay↗
PubMed1990

Introduction.

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Journal Article↗
PubMed1990

General methods and materials.

In the winter of 1982-83 an experiment was initiated at the University of Hohenheim to investigate the long-term effects of near ambient concentrations of O(3), SO(2), and simulated acidic rain and fog, alone and in combination, on mineral cycling, physiology, biochemistry and anatomy of Norway spruce (Picea abies L. Karst.), Silver fir (Abies alba Mill.) and European beech (Fagus silvatica L.) seedlings in model ecosystems. Open-top chambers above soil lysimeters were protected with shelters 1 m above the open-top against intrusion of ambient dust and rain. The soil, a replaced acid brown earth with a base saturation of 20-30% was from the Black Forest region of the Federal Republic of Germany. This paper describes the technical design aspects of the study, including chamber construction and ventilation, SO(2) and O(3) application and monitoring, simulated precipitation forms and dispensing features, and the environmental parameters monitored. A short description of the plants used and the soil status is also presented. Chamber climatic and edaphic conditions allowed tree seedling normal growth over the five years of study. The pollutant levels within the appropriate chambers were comparable to ambient concentrations found at southwest German forest sites and varied with weather conditions.

Journal Article↗
PubMed1990

Mineral content in the soil and tree foliage.

Seedlings of fir (Abies alba Mill.) and spruce (Picea abies L. Karst.) were fumigated with SO(2), O(3) and SO(2) + O(3) in open-top chambers (OTCs) for almost 5 vegetation periods. As background stress, simulated rain of pH 4.0 was applied. Nutrient content of soil, soil solutions, and trees was investigated and balanced. In the upper partition of the soil high concentrations of exchangeable Ca(2+) were found in all chambers. The SO(2) and SO(2) + O(3) treatments led to increased Ca(2+), Mg(2+) and Mn(2+) concentrations in soil solution and the pool of exchangeable protons increased. This response was most evident in the SO(2) and SO(2) + O(3) chambers and less clear in the filtered pH 5.0 control chamber. In the SO(2) treatment increased Mn and S levels were found in the needles. Ca content in the needles showed a decreasing trend. O(3) alone had no consistent effect on needle nutrient content.

Journal Article↗
PubMed1990

CO2/H2O gas exchange parameters of one- and two-year-old needles of spruce and fir.

Gas exchange was characterized in one- and two year-old spruce (Picea abies L. Karst.) and fir seedlings (Abies alba Mill.) which had been exposed to low levels of ozone, sulfur dioxide and simulated rain or a combination of all three variables in open top chambers from 1983 through 1988. The gas exchange measurements were carried out in March 1988 at the end of the five year experiment. The twigs examined did not exhibit any visible sign of injury, specifically no differences were apparent between trees under the treatments of simulated acidic rain at pH 5.0 and pH 4.0. The study of carbon dioxide response curves showed different effects of the pollutants on the tree species. One-Year-old spruce needles treated with O(3) and simulated acidic precipitation pH 4.0 showed noticeable reduction of net photosynthetic rate. Exposure to the combination O(3) and SO(2) at pH 4.0 resulted in a significant depression of photosynthesis in two-year-old needles Transpiration rate was not decreased to a similar extent. No changes either in photosynthesis or transpiration were found in spruce under fumigation with SO(2) alone. These results indicate that ozone is the principal cause of changes in photosynthetic performance of spruce. It alters mesophyll response rather than reducing stomatal conductance. The specific changes that occur in the mesophyll could be diagnosed as inactivation of a carbon fixing enzyme as well as damage of the electron transport system. Fir seem to be more tolerant to ozone. No changes in photosynthesis and transpiration following exposure to O(3) alone were found. However, SO(2) fumigation, alone or in combination with O(3), resulted in a marked decrease of photosynthetic performance. Particularly, carboxylation efficiency and also maximum carboxylation velocity were depressed indicating a reduction in carbon fixing enzyme activity. No differences between single and combined fumigation treatments regarding these variables were determined. However, parameters measured to determine changes in electron transport rate showed a higher depression in the presence of both pollutants. Transpiration also was reduced by SO(2).

Journal Article↗
PubMed1990

Visible injury responses.

During a five year experiment on the causes of forest disease, symptoms of visible injury and pest infestations in trees treated with various air pollutants in open-top chambers were observed. Though the long-term experiment was originally not intended to include such investigations, insect infestation and some discoloration of the trees (Beech, Fagus sylvatica; Fir, Abies alba; Spruce, Picea abies) could not be avoided. Abundance and size of some of the insects were measured after two years and at the end of the experiment. Because it was unknown when the first infestation in the chambers occurred, quantitative investigations of the population size provided little information. Visible injury on leaves and needles was infrequent in general. When it occurred, it appeared to be caused by at least three stress factors. However, three different types of symptoms on beech and fir could be attributed mainly to air pollutants. These symptoms consisted of two types of foliar necrosis and browning in beech and needle tip chlorosis in fir. These symptoms have been observed under certain conditions in the German forests. The spruce clone used, however, developed no injuries which could be connected definitely to treatment effects.

Journal Article↗
PubMed1990

Performance of some growth variables.

European beech (Fagus sylvatica L.), Norway spruce (Picea abies L. Karst.) and Silver fir (Abies alba Mill.) were exposed to low concentrations of ozone (O(3)) and sulfur dioxide (SO(2)), alone and combined, and simulated acid rain (pH 4.0) in sheltered open-top chambers in Hohenheim (Southwest Germany) for almost five years. The concentrations of O(3) and SO(2) used were related to annual ambient average found in southern West Germany. Two control chambers were ventilated with charcoal filtered air and rainfall was simulated at pH 4.0 and 5.0. Because of large dense plant growth in the chambers it was only possible to measure uncompleted growth of shoots in the upper canopy. Therefore, growth analysis was restricted to this area. The treatment with acidic precipitation decreased the annual shoot growth of beech and reduced leaf surface area of those trees. Exposure to SO(2), O(3) alone and in combination resulted in further reduction of shoot length and leaf surface area. Fumigation with SO(2) and O(3) + SO(2) caused insignificant decreases of shoot length, total dry weight and needle surface area of spruce. The lateral leader shoot growth of spruce exposed to O(3) was significantly reduced only in the last year of the experiment. Growth rates of the spruce exposed to charcoal filtered air and non-acidic precipitation were reduced more than those of beech and fir. Growth variables determined for fir reflected different rates of incremental change. Exposure to O(3) resulted in the largest dry matter production of all fir groups but those exposed to charcoal filtered air and non-acidic precipitation responded with the best lateral leader shoot growth, lowest specific leaf area (SLA) and leaf area ratio (LAR) respectively indicating best metabolic efficiency. At the conclusion of this study a classification of sensitivity was developed for the tree species.

Journal Article↗