Bone Substitute Effect on Vascularization and Bone Remodeling after Application of phVEGF165 Transfected BMSC
- VEGF (vascular endothelial growth factor) promotes vascularization and remodeling of bone substitutes. The aim of this study was to examine the effect of distinct resorbable ceramic carriers on bone forming capacities of VEGF transfected bone marrow stromal cells (BMSC). A critical size defect of the radius in rabbits was filled either by a low surface scaffold called beta-TCP (tricalciumphsphate) or the high surface scaffold CDHA (calcium deficient hydroxy-apatite) loaded with autologous BMSC, which were either transfected with a control plasmid or a plasmid coding for phVEGF165. They were compared to unloaded scaffolds. Thus, six treatment groups (n = 6 in each group) were followed by X-ray over 16 weeks. After probe retrieval, the volume of new bone was measured by micro-CT scans and vascularization was assessed in histology. While only minor bone formation was found in both carriers when implanted alone, BMSC led to increased osteogenesis in both carriers. VEGF promoted vascularization of the scaffolds significantly in contrast to BMSC alone. Bone formation was increased in the beta-TCP group, whereas it was inhibited in the CDHA group that showed faster scaffold degradation. The results indicate that the interaction of VEGF transfected BMSC with resorbable ceramic carrier influences the ability to promote bone healing.
Der deutsche Protestantismus in Amerika
Die Lage der Karstlandschaft Südharz
- Am Südrand des Harzes, des nördlichsten deutschen Mittelgebirges, erstreckt sich die mehr als 100 km lange Sulfatkarstlandschaft Südharz. Es ist sicher kein Zufall, dass Johannes THAL im Jahr 1588 in der "Sylva Hercynia" (220), der ersten publizierten Flora Deutschlands, ein Gebiet des Südharzes beschreibt, das bezüglich der Artenvielfalt seinesgleichen sucht. Diese Artenmannigfaltigkeit sowohl der Pflanzen- als auch der Tierwelt wird vor allem durch die hier zutage tretenden Zechsteinablagerungen mit gut wasserlöslichen Gipsen, Anhydriten und Salzen bedingt.
Site of cochlear stimulation and its effect on electrically evoked compound action potentials using the MED-EL standard electrode array
- Background: The standard electrode array for the MED-EL MAESTRO cochlear implant system is 31 mm in length which allows an insertion angle of approximately 720°. When fully inserted, this long electrode array is capable of stimulating the most apical region of the cochlea. No investigation has explored Electrically Evoked Compound Action Potential (ECAP) recordings in this region with a large number of subjects using a commercially available cochlear implant system. The aim of this study is to determine if certain properties of ECAP recordings vary, depending on the stimulation site in the cochlea. Methods: Recordings of auditory nerve responses were conducted in 67 subjects to demonstrate the feasibility of ECAP recordings using the Auditory Nerve Response Telemetry (ART™) feature of the MED-EL MAESTRO system software. These recordings were then analyzed based on the site of cochlear stimulation defined as basal, middle and apical to determine if the amplitude, threshold and slope of the amplitude growth function and the refractory time differs depending on the region of stimulation. Results: Findings show significant differences in the ECAP recordings depending on the stimulation site. Comparing the apical with the basal region, on average higher amplitudes, lower thresholds and steeper slopes of the amplitude growth function have been observed. The refractory time shows an overall dependence on cochlear region; however post-hoc tests showed no significant effect between individual regions. Conclusions :Obtaining ECAP recordings is also possible in the most apical region of the cochlea. However, differences can be observed depending on the region of the cochlea stimulated. Specifically, significant higher ECAP amplitude, lower thresholds and steeper amplitude growth function slopes have been observed in the apical region. These differences could be explained by the location of the stimulating electrode with respect to the neural tissue in the cochlea, a higher density, or an increased neural survival rate of neural tissue in the apex. Trial registration: The Clinical Investigation has the Competent Authority registration number DE/CA126/AP4/3332/18/05.
The control of root-eating scarabaeid grubs in Queensland cane-fields
- The world-wide damage caused by the larvae of various lamellicorn beetles to sugar-cane, cassava, pasture land, root crops, and miscellaneous economic trees and plants, has engaged the undivided attention of many scientists during the last thirty years or more. The "White Grub" question in America, the notorious Cockchafer or "May Bug" in Europe, and the formidable "Grub Pest" of Australian cane-fields, constitute exceedingly complex problems which have for many years defied the efforts of entomologists, and at the present time, although partially solved, cock chafer beetles still continue to be responsible for tremendous financial losses. I t is interesting to note that the destructive species in each of these three examples are classed amongst the Melolonthinae, most of the grubs of which subfamily, in addition to their habit of ingesting soil and extracting from it organic matter, also devour living roots and the growing vegetable tissue of harder underground portions of plants. While the· majority of Queensland cane-beetles (including our most destructive) belong to the M elolonthinae; the subfamily Rutelinae. is also represented in our cane-fields by two species, both of which, however, happen to be of minor importance. In the present article it is my intention to deal with six of our northern scarabaeid beetles, all of which are common at times under cane-stools, and inflict damage of a more or less serious nature to the setts, roots, and subterranean basal portions of growing cane-sticks.
"Workshop zur Taxonomie mitteleuropäischer Spinnen" in Erlangen (8. - 10.01.1993): Taxonomie und Faunistik der kleinen Euophrys-Arten und der Gattungen Neaetha und Pellenes (Salticidae)
Karl Hermann Harms
Otto von Helversen
- Da innerhalb der Araneae Mitteleuropas immer noch taxonomische Probleme bestehen, haben wir begonnen, systematisch schwierige Gattungen im Teamwork zu bearbeiten.
Unmasking a temperature-dependent effect of the P. anserina i-AAA protease on aging and development
Heinz D. Osiewacz
- Different molecular pathways involved in maintaining mitochondrial function are of fundamental importance to control cellular homeostasis. Mitochondrial i-AAA protease is part of such a surveillance system, and PaIAP is the putative ortholog in the fungal aging model Podospora anserina. Here, we investigate the role of PaIAP in aging and development. Deletion of the gene encoding PaIAP resulted in a specific phenotype. When incubated at 27°C, spore germination and fruiting body formation are not different from that of the corresponding wild-type strain. Unexpectedly, the lifespan of the deletion strain is strongly increased. In contrast, cultivation at an elevated temperature of 37°C leads to impairments in spore germination and fruiting body formation and to a reduced lifespan. The higher PaIAP abundance in wild-type strains of the fungus grown at elevated temperature and the phenotype of the deletion strain unmasks a temperature-related role of the protein. The protease appears to be part of a molecular system that has evolved to allow survival under changing temperatures, as they characteristically occur in nature.
Age-related cellular copper dynamics in the fungal ageing model Podospora anserina and in ageing human fibroblasts
Christian Quintus Scheckhuber
Bernd O. Kolbesen
Heinz D. Osiewacz
- In previous investigations an impact of cellular copper homeostasis on ageing of the ascomycete Podospora anserina has been demonstrated. Here we provide new data indicating that mitochondria play a major role in this process. Determination of copper in the cytosolic fraction using total reflection X-ray fluorescence spectroscopy analysis and eGfp reporter gene studies indicate an age-related increase of cytosolic copper levels. We show that components of the mitochondrial matrix (i.e. eGFP targeted to mitochondria) become released from the organelle during ageing. Decreasing the accessibility of mitochondrial copper in P. anserina via targeting a copper metallothionein to the mitochondrial matrix was found to result in a switch from a copper-dependent cytochrome-c oxidase to a copper-independent alternative oxidase type of respiration and results in lifespan extension. In addition, we demonstrate that increased copper concentrations in the culture medium lead to the appearance of senescence biomarkers in human diploid fibroblasts (HDFs). Significantly, expression of copper-regulated genes is induced during in vitro ageing in medium devoid of excess copper suggesting that cytosolic copper levels also increase during senescence of HDFs. These data suggest that the identified molecular pathway of age-dependent copper dynamics may not be restricted to P. anserina but may be conserved from lower eukaryotes to humans.
Performance of diethylene glycol-based particle counters in the sub-3 nm size range
- When studying new particle formation, the uncertainty in determining the "true" nucleation rate is considerably reduced when using condensation particle counters (CPCs) capable of measuring concentrations of aerosol particles at sizes close to or even at the critical cluster size (1–2 nm). Recently, CPCs able to reliably detect particles below 2 nm in size and even close to 1 nm became available. Using these instruments, the corrections needed for calculating nucleation rates are substantially reduced compared to scaling the observed formation rate to the nucleation rate at the critical cluster size. However, this improved instrumentation requires a careful characterization of their cut-off size and the shape of the detection efficiency curve because relatively small shifts in the cut-off size can translate into larger relative errors when measuring particles close to the cut-off size.
Here we describe the development of two continuous-flow CPCs using diethylene glycol (DEG) as the working fluid. The design is based on two TSI 3776 counters. Several sets of measurements to characterize their performance at different temperature settings were carried out. Furthermore, two mixing-type particle size magnifiers (PSM) A09 from Airmodus were characterized in parallel. One PSM was operated at the highest mixing ratio (1 L min−1 saturator flow), and the other was operated in a scanning mode, where the mixing ratios are changed periodically, resulting in a range of cut-off sizes. The mixing ratios are determined by varying the saturator flow, where the aerosol flow stays constant at 2.5 L min−1. Different test aerosols were generated using a nano-differential mobility analyser (nano-DMA) or a high-resolution DMA, to obtain detection efficiency curves for all four CPCs. One calibration setup included a high-resolution mass spectrometer (APi-TOF) for the determination of the chemical composition of the generated clusters. The lowest cut-off sizes were achieved with negatively charged ammonium sulfate clusters, resulting in cut-offs of 1.4 nm for the laminar flow CPCs and 1.2 and 1.1 nm for the PSMs. A comparison of one of the laminar-flow CPCs and one of the PSMs measuring ambient and laboratory air showed good agreement between the instruments.
Ein Nachklang rationalistischer Mythendeutung bei Vitruv