Die operative Behandlung der Rhizarthrose mittels Resektions-Interpositions- Arthroplastik : Eine Verlaufsbeobachtung

Die Arthrose des Daumensattelgelenkes ist eine häufige degenerative Erkrankung an der Hand, die zu einer erheblichen Beeinträchtigung der Betroffenen im Alltag wie im Beruf führt. Im Vordergrund der beklagten Beschwerden stehen der Schmerz und die damit verbundene Kraftminderung, insbesondere bei der Ausübung der Greiffunktion des Daumens. Für die operative Therapie stehen mehrere Verfahren zur Verfügung. Diese reichen von der einfachen Resektion des Os trapezium über Interposition von verschiedenen Materialien bis hin zu aufwendigen Aufhängearthroplastiken durch Sehnen. Ziel ist dabei immer die Erhaltung der Mobilität, Stabilität, Schmerzfreiheit und ausreichende Kraftentwicklung. In der vorliegenden Verlaufsstudie wurden 107 Patienten mit Rhizarthrose erfasst. Die Auswertung beinhaltete subjektive Kriterien (Schmerzen, Kraftempfinden, Geschicklichkeit, Belastbarkeit, Zufriedenheit mit dem kosmetischem Ergebnis und Gesamtbeurteilung durch den Patienten) und objektive Messdaten (Bewegungsausmaß, Kraft, Proximalisation des Metakarpale I). Die Datenerfassung erfolgte prospektiv. Die Trapeziumresektion mit Sehneninterposition ist ein operationstechnisch einfaches Verfahren und stellt unsere Methode der Wahl zur Behandlung der Sattelgelenksarthrose dar. Sie bietet aufgrund unserer Daten gute Aussichten auf eine dauerhafte Schmerzbefreiung mit ausreichend guter Funktion, Mobilität und Kraft und ohne das Risiko von Komplikationen durch implantiertes Fremdmaterial. Nicht zuletzt unterstreicht auch die hohe Patientenzufriedenheit die Berechtigung unserer Operationsmethode

Böden marginaler Standorte - Eigenschaften, Limitierungen und Potentiale

Eine zunehmende Knappheit ackerbaulicher Standorte und der zugleich steigende Bedarf an nachwachsenden Rohstoffen für die energetische und stoffliche Nutzung lösen verstärkt Konflikte zwischen der Nahrungsmittelproduktion und der Biomasseproduktion aus. Marginale Standorte kommen entsprechend immer stärker in den Blickpunkt als mögliche Erweiterungsflächen für die Biomasseproduktion. In der wissenschaftlichen Auseinandersetzung fehlt allerdings eine eindeutige Definition für derartige marginale Standorte. Gerade im Hinblick auf eine mögliche Reduzierung von Nutzungskonflikten ist die Abgrenzung zu stillgelegten, aber agrarisch nutzbaren Standorten oder zu natürlichen Badlands, mit naturschutzfachlichen Potentialen oftmals schwierig. Das EU H2020-Projekt SEEMLA untersucht Potentiale und Verfügbarkeit von marginalen Standorten europaweit. In Deutschland, Griechenland und der Ukraine wurden Pilotstandorte eingerichtet, auf denen der Anbau von Bioenergiepflanzen exemplarisch durchgeführt wird. Für eine erste Bewertung der Standortspotentiale und auch der Ursachen der Marginalität der Standorte wurden Bodenuntersuchungen an allen Pilotstandorten nach den Vorgaben des Muencheberger Soil Quality Rating-Verfahrens (SQR) (1) durchgeführt und die Standorte klassifiziert. Das SQR-Verfahren bewertet ausgewählte Boden- und Standortseigenschaften und bezieht zusätzlich mögliche limitierende Faktoren (Hazard Indicators) wie Versauerung, Versalzung, Vernässung etc. mit ein, um eine Gesamtbewertungszahl zur Bodenfruchtbarkeit zu ermitteln. Dieser Beitrag stellt anhand der SEEMLA-Standorte exemplarisch Böden marginaler Standorte vor. Mit Hilfe der SQR Hazard Indicators werden charakteristische limitierende Faktoren vorgestellt. Es wird zudem versucht, die untersuchten Standorte in eine mögliche Klassifikation marginaler Standorte einzupassen und ihre Eignung für die Biomasseproduktion einzuschätzen

Messung von Schwermetallen und Hauptelementen in anthropogen geprägten Böden mittels feldportabler Röntgenfluoreszenzanalyse (FP RFA)

Der Einsatz eines feldportablen Röntgenfluoreszenzanalysators (FP RFA) vom Typ NITON XL3t, zur Messung von Schwermetallen und Hauptelementen in Bodenproben wurde am Beispiel eines ehemaligen Rieselfelds untersucht. Die Gegenüberstellung der RFA Daten zu nasschemisch gewonnenen Messwerten zeigte insbesondere für die Elemente Kupfer, Blei und Zink eine starke Korrelation zwischen beiden Datensätzen. Die Elemente Calcium, Kalium, Phosphor und Magnesium konnten im untersuchten Messwertbereich nicht befriedigend analysiert werden. Die in-situ Messung ergab mit Labordaten vergleichbare Messwerte und Messwertverteilungen, wenngleich im Feld z.T. deutlich höhere Metallgehalte bestimmt wurden

Использование двигателя-маховика для создания управляющих моментов космического аппарата

In this article we present a comprehensive study of microcrystalline silicon (PC-Si:H) p-i-n solar cells prepared by using plasma-enhanced chemical vapor deposition (PECVD) at 13.56 MHz excitation frequency. In the first step the cell development was performed in a small area PECVD reactor showing the relationship between the deposition process parameters and the resulting solar cell performance. Subsequent up-scaling to a substrate area of 30 X 30 cm confirmed the scalability of optimized deposition parameters to large area reactors. We investigated the deposition regime of high rf power P (rf) (0.25-0.7 W/cm(2)) and high deposition pressure P (dep) (1 - 11 Torr) for the muc-Si:H i layer. Furthermore, the influence of silane concentration and deposition temperature was studied. A transition between amorphous and microcrystalline growth could be achieved by a variation of either deposition pressure, plasma power, or silane concentration. The best microcrystalline silicon solar cells were prepared close to the transition to amorphous growth. A high deposition pressure was a prerequisite for obtaining, high quality material at a high growth rate. The best solar cell efficiencies achieved so far are 8.1% and 6.6% at i-layer growth rates of 5 and 10 Angstrom/s, respectively, for muc-Si:H single junction cells. Applied in a-Si:H/muc-Si:H tandem cells a stabilized efficiency of 10.0% was achieved. (C) 2002 American Vacuum Society

Assessment and quantification of marginal lands for biomass production in Europe using soil-quality indicators

The cultivation of bioenergy plants in fertile, arable lands increasingly results in new land use conflicts with food production and cannot be considered as sustainable. Marginal lands have been frequently considered as potential alternatives for producing bioenergy from biomass. However, clear definitions and assessment methods for selecting marginal lands and for calculating potentials are still widely missing. The project “SEEMLA” aims at triggering the exploitation of currently underused marginal lands for biomass production for energy purposes. Study sites have been selected in different European countries: Germany, Greece, and Ukraine. The selected sites represent a wide variety of different types of marginal lands. Based on a soil assessment set given by the Muencheberg Soil Quality Rating (SQR) system potentially “marginal” sites have been investigated. The SQR system allows for clearly distinguishing between soils of higher and lower quality. Soils with SQR scores below 40 are regarded as “marginal”. They can be classified into different groups with regard to the importance of soil hazard indicators as evaluated by the SQR approach. The calculated SQR scores correlate significantly with biomass yields of bioenergy plants. Further, the SQR method was adapted for use in a GIS study on marginal-land potentials in Europe. Thus, 46&thinsp;% of the investigated European area could be classified as “marginal” with SQR scores below 40. From that area 22.6&thinsp;% can be considered as potentially suitable for producing renewable resources after eliminating protected sites or other places not suitable for any kind of land use. Taking the ecological demands of selected bioenergy plants into account it is possible to give first preliminary recommendations for regional crop cultivation. It can be concluded that Europe offers a large potential for renewable resources from marginal sites. However, the implementation into practice is often impeded by missing or varying policies and regulations. A proper implementation needs clear regulations and also incentives for farmers at the European level.</p

hMYH and hMTH1 cooperate for survival in mismatch repair defective T-cell acute lymphoblastic leukemia

hMTH1 is an 8-oxodGTPase that prevents mis-incorporation of free oxidized nucleotides into genomic DNA. Base excision and mismatch repair pathways also restrict the accumulation of oxidized lesions in DNA by removing the mis-inserted 8-oxo-7,8-dihydro-2'-deoxyguanosines (8-oxodGs). In this study, we aimed to investigate the interplay between hMYH DNA glycosylase and hMTH1 for cancer cell survival by using mismatch repair defective T-cell acute lymphoblastic leukemia (T-ALL) cells. To this end, MYH and MTH1 were silenced individually or simultaneously using small hairpin RNAs. Increased sub-G1 population and apoptotic cells were observed upon concurrent depletion of both enzymes. Elevated cell death was consistent with cleaved caspase 3 accumulation in double knockdown cells. Importantly, overexpression of the nuclear isoform of hMYH could remove the G1 arrest and partially rescue the toxicity observed in hMTH1-depleted cells. In addition, expression profiles of human DNA glycosylases were generated using quantitative reverse transcriptase–PCR in MTH1 and/or MYH knockdown cells. NEIL1 DNA glycosylase, involved in repair of oxidized nucleosides, was found to be significantly downregulated as a cellular response to MTH1–MYH co-suppression. Overall, the results suggest that hMYH and hMTH1 functionally cooperate for effective repair and survival in mismatch repair defective T-ALL Jurkat A3 cells

The Role of Mismatch Repair, Base Excision Repair and PARP-1 in the Processing of Oxidative DNA Damage

Our DNA is constantly exposed to spontaneous oxidative stress, which results from metabolic byproducts and which represents a key threat to genomic stability. Oxidation of DNA results in accumulation of the mutagenic 8-hydroxy-2’- deoxyguanosine (GO), which is mainly removed by the base excision repair (BER) pathway. G/C base pairs are oxidized to GO/Cs, which are recognized by oxoguanine DNA glycosylase (OGG1) and corrected to G/Cs, with the assistance of the downstream BER machinery. During replication, GO can mispair with adenine. GO/A mispairs are addressed by MYH-initiated BER that removes the As and replaces them with Cs to generate GO/Cs, which are substrates for OGG1- dependent BER. Dysfunction of MYH leads to G:C to T:A transversions and is linked to MYH-associated polyposis (MAP). During the past decade, repair of oxidative DNA lesions such as GO was shown to involve also the postreplicative mismatch repair system (MMR), but its role within this process remained obscure. GO/A mispairs were known to be poor substrates for MMR, but we show here that, in an in vitro MMR assay based on circular lesion- containing plasmids and human cell extracts, the intermediates of GO/A - but not GO/C - processing by BER can serve as strand discrimination signals for MMR. These observations were not restricted to human cell extracts, but were observed also in extracts of Xenopus laevis eggs. During S-phase, GO would be present predominantly in the parental DNA strand. Thus, “hijacking” of strand breaks arising during MYH-dependent GO/A processing by BER would help direct the mismatch repair process correctly to the daughter strand. In contrast, OGG1- generated nicks at GO/C sites would direct MMR erroneously to the parental strand. Our data thus show that BER-mediated processing of oxidative DNA damage is coordinated to help MMR improve replication fidelity. In a complementary study, we set out to study the interactome of the mismatch recognition factor MutSα during oxidative DNA damage response. We had hoped that identification of interaction partners of these MMR proteins might help us understand the details of the interplay of the different pathways of DNA metabolism and DNA damage signaling in cells subjected to oxidative stress. I generated a novel set of expression vectors and cell lines that could be used for future mass spectrometric analysis of the interacting partners of MutSα. I also confirmed that MMR deficiency leads to a decreased cell survival and a prolonged G2/M arrest during oxidative stress. Poly(ADP-ribose) polymerase 1(PARP-1) is an enzyme that is extremely rapidly activated by single-strand breaks (SSBs), to which it binds with high affinity. This 'nick protector' enzyme has been assigned a role in BER that is currently ill- defined, however, it has recently acquired substantial clinical importance, because its inhibition effectively kills BRCA1/-2 deficient breast and ovarian cancer cells. PARP inhibition is generally believed to give rise to toxic SSB/PARP-1 complexes that can only be repaired in the presence of BRCA1/-2, but the underlying causes of those SSBs are undefined yet. We wanted to learn whether these breaks might stem from the processing of spontaneous oxidative damage. Using cell survival assays with human BRCA1-deficient cell lines, we show that MYH knockdown attenuates the toxic effect of PARP inhibitors. These findings show that DNA oxidation is a source of lesions that contribute to the toxicity of PARP inhibition in BRCA-deficient cells and suggest that augmentation of oxidative damage processing might increase the efficacy of PARP inhibitors in the clinic