Comparison of Aminoglycoside Antibiotics and Cobalt Chloride for Ablation of the Lateral Line System in Giant Danios.

The mechanoreceptive lateral line system in fish is composed of neuromasts containing hair cells, which can be temporarily ablated by aminoglycoside antibiotics and heavy metal ions. These chemicals have been used for some time in studies exploring the functional role of the lateral line system in many fish species. However, little information on the relative effectiveness and rate of action of these chemicals for ablation is available. In particular, aminoglycoside antibiotics are thought to affect canal neuromasts, which sit in bony or trunk canals, differently from superficial neuromasts, which sit directly on the skin. This assumed ablation pattern has not been fully quantified for commonly used lateral line ablation agents. This study provides a detailed characterization of the effects of two aminoglycoside antibiotics, streptomycin sulfate and neomycin sulfate, and a heavy metal salt, cobalt (II) chloride hexahydrate (CoCl2), on the ablation of hair cells in canal and superficial neuromasts in the giant danio (Devario aequipinnatus) lateral line system, as a model for adult teleost fishes. We also quantified the regeneration of hair cells after ablation using CoCl2 and gentamycin sulfate to verify the time course to full recovery, and whether the ablation method affects the recovery time. Using a fluorescence stain, 4-Di-2-ASP, we verified the effectiveness of each chemical by counting the number of fluorescing canal and superficial neuromasts present throughout the time course of ablation and regeneration of hair cells. We found that streptomycin and neomycin were comparably effective at ablating all neuromasts in less than 12 h using a 250 µM dosage and in less than 8 h using a 500 µM dosage. The 500 µM dosage of either streptomycin or neomycin can ablate hair cells in superficial neuromasts within 2-4 h, while leaving those in canal neuromasts mostly intact. CoCl2 (0.1 mM) worked the fastest, ablating all of the hair cells in less than 6 h. Complete regeneration of the neuromasts in the lateral line system took 7 days regardless of chemicals used to ablate the hair cells. This study adds to the growing knowledge in hearing research about how effective specific chemicals are at ablating hair cells in the acoustic system of vertebrates.

El sistema de la línea lateral mecanorreceptora en los peces está compuesto de neuromastos que contienen células ciliadas, que pueden ser ablacionadas temporalmente con antibióticos aminoglucósidos e iones de metales pesados. Estos productos químicos se han utilizado durante algún tiempo en estudios que exploran el papel funcional del sistema de línea lateral en muchas especies de peces. Sin embargo, se dispone de poca información sobre la eficacia relativa y la tasa de acción de estos productos químicos para la ablación. En particular, se cree que los antibióticos aminoglucósidos afectan a los neuromastos de canal, que están posicionados en los canales de hueso o del tronco, de manera diferente a los neuromastos superficiales, que están posicionados directamente sobre la piel. Este supuesto patrón de ablación no se ha cuantificado por completo para los agentes de ablación de la línea lateral de uso común. Este estudio proporciona una caracterización detallada de los efectos de dos antibióticos aminoglucósidos, sulfato de estreptomicina y sulfato de neomicina, y una sal de metal pesado, hexahidrato de cloruro de cobalto (II) (CoCl2), en la ablación de las células ciliadas en neuromastos superficiales y de canal en el sistema de línea lateral en el danio gigante (Devario aequipinnatus), como un modelo para peces teleósteos adultos. También cuantificamos la regeneración de las células ciliadas después de la ablación con CoCl2 y sulfato de gentamicina para verificar el curso del tiempo hasta la recuperación completa y si el método de ablación afecta el tiempo de recuperación. Usando una tinción de fluorescencia, 4-Di-2-ASP, verificamos la efectividad de cada químico contando el número de fluorescentes neuromastos superficialises y de canal presentes a lo largo del tiempo de ablación y regeneración de las células ciliadas. Encontramos que la estreptomicina y la neomicina fueron comparablemente efectivas en la ablación de todos los neuromastos en menos de 12 horas usando una dosis de 250 µM y en menos de 8 horas usando una dosis de 500 µM. La dosis de 500 µM de estreptomicina o neomicina puede eliminar las células ciliadas en los neuromastos superficiales dentro de 2 a 4 horas, dejando las celulas de los neuromastos de canal casi intactas. CoCl2 (0,1 mM) funcionó más rápido, eliminando todas las células ciliadas en menos de 6 horas. La regeneración completa de los neuromastos en el sistema de la línea lateral tomó siete días, independientemente de los productos químicos utilizados para extirpar las células ciliadas. Este estudio se suma al creciente conocimiento en la investigación auditiva sobre cuán efectivos son los químicos específicos para eliminar las células ciliadas en el sistema acústico de los vertebrados.

[Guideline "Legal evaluation after closed brain injury in adulthood"]. / Leitlinie "Begutachtung nach gedecktem Schädel-Hirntrauma im Erwachsenenalter".

In 2005 and 2013, the "Deutsche Gesellschaft für Neurowissenschaftliche Begutachtung" (German Society for Neuroscientific Evaluation) together with other societies developed and consented guidelines fort the legal evaluation of patients with closed head injuries and published them trough the National Working Group of Scientific Medical Societies and in this journal. Five years later, a revision was necessary, this was developed on the higher S2 k level of consent through a Delphi conference.

Surface enhanced resonance Raman spectroscopy of iron Hangman complexes on electrodes during electrocatalytic oxygen reduction: advantages and problems of common drycast methods.

Drycast methods have been used frequently in recent decades to adsorb a range of synthetic catalysts on electrodes. The uncoordinated multilayers that are formed via this immobilization method can however have a strong impact on the electrocatalytic reaction pathway as slow electron transfer and intermolecular interactions can alter the chemistry of the catalysts on the surface. To gain insight into the structure of Fe porphyrin Hangman catalysts during electrocatalytic oxygen reduction a combination of electrochemistry and surface enhanced resonance Raman spectroscopy (SERRS) was applied. The Hangman complexes were attached to the electrodes via different methods and the influence of the immobilisation technique on oxygen chemistry was studied. In multilayer systems, new intermediates could be identified via potential dependent SERRS that were not present in solution or in monolayer systems under catalytic conditions. A comparison of Raman spectra obtained either via Soret or Q-band excitation showed that the porphyrin symmetry is strongly distorted under reducing conditions, which was interpreted by the transient formation of dimer complexes during catalysis.

2nd coordination sphere controlled electron transfer of iron hangman complexes on electrodes probed by surface enhanced vibrational spectroscopy.

Iron hangman complexes exhibit improved catalytic properties regarding O2 and H2O2 reduction, which are attributed to the presence of a proton donating group in defined vicinity of the catalytic metal centre. Surface enhanced resonance Raman (SERR) and IR (SEIRA) spectro-electrochemistry has been applied concomitantly for the first time to analyse such iron hangman porphyrin complexes attached to electrodes in aqueous solution. While the SERR spectra yield information about the redox state of the central iron, the SEIRA spectra show protonation and deprotonation events of the 2nd coordination sphere. To investigate the influence of a proton active hanging group on the heterogeneous electron transfer between the iron porphyrin and the electrode, two hangman complexes with either an acid or ester functional group were compared. Using time resolved SERR spectroscopy the electron transfer rates of both complexes were determined. Complexes with an acid group showed a slow electron transfer rate at neutral pH that increased significantly at pH 4, while complexes with an ester group exhibited a much faster, but pH independent rate. SEIRA measurements were able to determine directly for the first time a pKa value of 3.4 of a carboxylic hanging group in the immobilized state that shifted to 5.2 in D2O buffer solution. The kinetic data showed an increase of the heterogeneous electron transfer rate with the protonation degree of the acid groups. From these results, we propose a PCET which is strongly modulated by the protonation state of the acid hanging group via hydrogen bond interactions.

Tuning of photocatalytic activity by creating a tridentate coordination sphere for palladium.

The synthesis and characterisation of an asymmetric potential bridging ligand bmptpphz (bmptpphz = 2,17-bis(4-methoxyphenyl)tetrapyrido[3,2-a:2',3'-c:3'',2''-h:2''',3'''-j] phenazine) is presented. This ligand contains a 1,10-phenanthroline (phen) and a 2,9-disubstituted phen sphere and possesses a strong absorbance in the visible. Facile coordination of the phen sphere to a Ru(tbbpy)2 core leads to Ru(bmptpphz) ([(tbbpy)2Ru(bmptpphz)](PF6)2; tbbpy = 4,4'-di-tert-butyl-2,2'-bipyridine). UV-vis, emission, resonance Raman and theoretical investigations show that this complex possesses all properties associated with a Ru(tpphz) ([(tbbpy)2Ru(tpphz)](PF6)2; tpphz = tetrapyrido[3,2-a:2',3'-c:3'',2''-h:2''',3'''-j] phenazine) moiety and that the ligand based absorbances in the vis-part also populate an MLCT like state. The coordination of a Pd-core in the new 2,9-disubstituted phen sphere is possible, leading to a cyclometallation. The tridentate complexation leads to changes in the UV-vis and emission behaviour. Furthermore, the stability of the Pd-coordination is significantly enhanced if compared to the unsubstituted Ru(tpphz). Ru(bmptpphz)PdCl proved to be an active photocatalyst for H2 evolution, albeit with lower activity than the mother compound Ru(tpphz)PdCl2.

Cellular distribution of metastasis suppressor 1 and the shape of cell bodies are temporarily altered in Engrailed-2 overexpressing cerebellar Purkinje cells.

Metastasis suppressor 1 (MTSS1, BEG4, MIM) is well described for its function as a metastasis suppressor gene and is expressed in a variety of tissues. However, only little is known about its expression in the central nervous system (CNS), and functions within the CNS have not been addressed so far. Here, we show that MTSS1 was expressed in postmitotic neurons of the cerebellar cortex. Within Purkinje cells, higher amounts of MTSS1 were temporarily localized in the axonal somatic compartment than in the dendritic compartment. In L7En-2 transgenic mice, in which the segment-polarity gene and regulator of neuronal maturation Engrailed-2 is overexpressed specifically in cerebellar Purkinje cells, MTSS1 was homogenously distributed within Purkinje cell somata throughout development. In parallel to the altered distribution of MTSS1 in L7En-2 Purkinje cells, L7En-2 Purkinje cell somata were distorted and in some cells invaginations of the plasma membrane were observed. These invaginations were only found in L7En-2 neurons, and displayed multiple synapses which could not be seen at the smooth surface of wildtype Purkinje cell somata. Current knowledge about MTSS1 function in vitro and the correlation between MTSS1 localization and the occurrence of membrane alterations in L7En-2 Purkinje cells described here suggest that MTSS1 might be involved in shaping neuronal membranes in vivo.

Helicopter emergency medical services accident rates in different international air rescue systems.

AIM: Each year approximately two to four helicopter emergency medical services (HEMS) crashes occur in Germany. The aim of the present study was to compare crash rates and fatal crash rates in Germany to rates in other countries. MATERIALS AND METHODS: A MEDLINE search from 1970 to 2009 was performed using combinations of the keywords "HEMS", "rescue helicopter", "accident", "accident rate", "crash", and "crash rate". The search was supplemented by additional published data. Data were compared on the basis of 10,000 missions and 100,000 helicopter flying hours. These data were allocated to specific time frames for analyis. RESULTS: Eleven relevant studies were identified. Five studies (three from Germany, one from the US, one from Australia) analyzing HEMS accidents on the basis of 10,000 missions were identified. Crash rates per 10,000 missions ranged between 0.4 and 3.05 and fatal crash rates between 0.04 and 2.12. In addition, nine studies (six from the US, two from Germany, one from Australia) used 100,000 flying hours as a denominator. Here, crash rates ranged between 1.7 and 13.4 and fatal crash rates between 0.91 and 4.7. CONCLUSIONS: Data and accident rates were inhomogeneous and differed significantly. Data analysis was impeded by publication of mean data, use of different time frames, and differences in HEMS systems.

Differential interaction of magnetic nanoparticles with tumor cells and peripheral blood cells.

PURPOSE: The separation of tumor cells from healthy cells is a vital problem in oncology and hematology, especially from peripheral blood. Magnetic assisted cell sorting (MACS) is a possibility to fulfill these needs. METHODS: Tumor cell lines and leukocytes from peripheral blood were incubated with carboxymethyl dextran-coated magnetic nanoparticles under various conditions and separated by MACS. RESULTS: We studied the interaction of magnetic nanoparticles devoid of antibodies with healthy and tumor cells. The magnetic nanoparticles interact with tumor cells and leukocytes and are located predominantly within the cell cytoplasm. Incubation of cell culture cells with magnetic nanoparticles led to a labeling of these cells without reduced biological properties for at least 14 days. The interaction of the magnetic nanoparticles with cells depends on several factors. The ionic strength (osmolality) of the solvent plays an important role. We could show that an increase in osmolality led to a dramatic reduction of labeled leukocytes. Tumor cells, however, are mildly affected. This could be detected not only in pure cultures of tumor cells or leukocytes but also in mixed cell populations. CONCLUSION: This observation gives us the opportunity to selectively label and separate tumor cells but not leukocytes from the peripheral blood.

Bone morphogenetic protein 2 (BMP-2) induces sequential changes of Id gene expression in the breast cancer cell line MCF-7.

Bone morphogenetic proteins (BMPs) are involved in the development of various organs including the mammary gland. They are well-regulated and act in a time-, concentration- and cell-type-specific manner. We found that BMP-2 is expressed in primary breast tumor tissue samples and in breast cancer cell lines. Hybridization of labeled cDNA, obtained from the breast cancer cell line MCF-7, against the Atlas human cDNA expression array revealed differential gene expression depending on BMP-2 treatment. The most prominent changes were observed for the helix-loop-helix proteins Id-1, Id-2 and Id-3. Id-1 expression had increased severalfold after 4 h and was even higher after 24 h. Id-2 and Id-3 were more strongly induced after 4 h and showed no further significant change after 24 h. Analysis of cell-cycle distribution revealed a marked increase of the sub-G1 phase after 48 h in serum-deprived cells. In the presence of BMP-2 no change was observed over 48 h indicating that BMP-2 does not induce apoptosis. In addition, expression of caspase-3 was reduced in BMP-2-treated cells after 24 h. In summary, our results clearly indicate that BMP-2 is a susceptibility factor keeping the cells ready for the integration of various other signals for cell progression.

Uptake and binding of radiolabelled phenylarsine oxide in 3T3-L1 adipocytes.

Phenylarsine oxide (PAO), a trivalent arsenical, has been shown to inhibit insulin-stimulated glucose transport in 3T3-L1 adipocytes, implicating vicinal dithiols in signal transmission [Frost & Lane (1985) J. Biol. Chem. 260, 2646-2652]. To assist in the direct identification of a PAO-binding protein which might be involved in this process, we have synthesized [3H]acetylaminophenylarsine oxide [( 3H]APAO) from the amino derivative of phenylarsine oxide (NPAO). To assess the inhibitory effect of the product, a dual-labelling experiment was performed which showed that [3H]APAO inhibited insulin-stimulated 2-deoxy[1-14C]glucose transport in 3T3-L1 adipocytes with a Ki of 21 microM, identical with that of the parent compound, NPAO. Further characterization revealed that over a wide concentration range, uptake of the labelled arsine oxide was linear. Although the dithiol reagent 2,3-dimercaptopropanol (DMP) reversed PAO-induced inhibition of transport, it had no effect on the uptake of [3H]APAO. In a simple fractionation experiment approx. 50% of the radioactivity was associated with the cytosolic fraction and 50% with the total membrane fraction. Identification of radiolabelled proteins by non-reducing SDS/PAGE revealed fraction-specific binding, although many proteins were observed. Covalent modification was time-dependent and could be reversed by addition of DMP. These data further support a role for vicinal dithiols in insulin-stimulated glucose transport. Additionally, the probe described may offer a new means with which to identify the inhibitory protein or, more globally, to investigate mechanisms of action of vicinal dithiol-containing proteins.

[Phospholipid content of subcellular structures in skeletal muscles after halothane loading in Landrace swine in relation to mating variants and genotype]. / Phospholipidgehalt subzellulärer Strukturen im Skelettmuskel nach Halothanbelastung bei Schweinen der Landrasse in Abhängigkeit von Anpaarungsvarianten und Genotyp.

Membraneous phospholipids of subcellular structures were determined from the musculature of German Landrace pigs of the GDR, following exposure to halothane. Mating variants A (H+ male X H+ female), B (H+ male X H- female), and C (H- male X H+ female) were used for positive responders (MHS), while variants B, C, and D (H- male X H- female) were used for negative responders (MHN). Four phospholipid fractions were recorded from the muscle samples for mitochondria and microsomes (according to SR section). Differences between the MHS and MHN groups for the above fractions and without consideration of mating variants and genotype were not observed, although unambiguous responses were exhibited by all animals, either positive or negative to halothan. Significant differences with regard to the above phospholipid fractions were recordable only for variant A (MHS group) as compared to D (MHN), in other words, for the homozygous genotypes, once the above results had been rearranged within MHS and MHN along with different mating variants and genotypes. However, no unambiguous results were obtainable for the heterozygous genotypes of mating variants B and C. Possible underlying reasons are discussed in some detail. The results obtained from mating variants A and D are likely to confirm earlier findings and seem to suggest that the sarcoplasmic reticulum is the primary site of origin of susceptibility to halothane or malignant hyperthermia.

Class position, work experience, and health.

This paper develops a Marxist analysis of the relationships between class position, work experience, the psychological effects of this experience, and subsequent health outcomes. Specifically, it is argued that the structural imperatives of capitalist production make work for those in working-class positions subject to greater routinization and less control than work for those in other class positions. Routinization and control are argued, in turn, to predictably affect two key psychological variables, self-esteem and stress, which are further argued to affect health in predictable ways. Position in the capitalist labor process is thus linked to health via the psychological consequences of the immediate work experience it engenders. Survey data from workers, managers, supervisors, and semi-autonomous employees in five capitalist firms are used to test the descriptive adequacy of this model linking capitalism to ill health for those in working-class positions.