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Highlights • Pre- and post-somatic segments of type I spiral ganglion neurons (SGNs) are unmyelinated in man. • Following hair cell loss and retrograde nerve degeneration SGNs survive as “mono-polar” cells in human deafness. • Non-myelinated Schwann cells may consolidate the neural cell bodies and protect SGNs from further degeneration. • Human SGNs can persist as electrically excitable mono-polar cells even after long-time deafness. • Robust survival of human SGNs is a prerequisite for cochlear implant function., Human auditory nerve afferents consist of two separate systems; one is represented by the large type I cells innervating the inner hair cells and the other one by the small type II cells innervating the outer hair cells. Type I spiral ganglion neurons (SGNs) constitute 96% of the afferent nerve population and, in contrast to other mammals, their soma and pre- and post-somatic segments are unmyelinated. Type II nerve soma and fibers are unmyelinated. Histopathology and clinical experience imply that human SGNs can persist electrically excitable without dendrites, thus lacking connection to the organ of Corti. The biological background to this phenomenon remains elusive. We analyzed the pre- and post-somatic segments of the type I human SGNs using immunohistochemistry and transmission electron microscopy (TEM) in normal and pathological conditions. These segments were found surrounded by non-myelinated Schwann cells (NMSCs) showing strong intracellular expression of laminin-β2/collagen IV. These cells also bordered the perikaryal entry zone and disclosed surface rugosities outlined by a folded basement membrane (BM) expressing laminin-β2 and collagen IV. It is presumed that human large SGNs are demarcated by three cell categories: (a) myelinated Schwann cells, (b) NMSCs and (c) satellite glial cells (SGCs). Their BMs express laminin-β2/collagen IV and reaches the BM of the sensory epithelium at the habenula perforata. We speculate that the NMSCs protect SGNs from further degeneration following dendrite loss. It may give further explanation why SGNs can persist as electrically excitable monopolar cells even after long-time deafness, a blessing for the deaf treated with cochlear implantation.

Nanoparticles as potential carriers for local drug transfer are an alternative to systemic drug delivery into the inner ear. We report on the first in vitro tests of a new ferrogel consisting of superparamagnetic iron oxide nanoparticles (SPIONs) and a Pluronic ® F127 (PF127) copolymer. Pluronic copolymers possess a unique viscosity-adjustable property that makes PF127 gels easy to handle compared to conventional cross-linked hydrogels. This ferrogel was successfully tested in cadaver human temporal bones as well as in organotypic explant cultures of mouse inner ears. SPIONs were identified by light microscopy and localized with different imaging modes in energy-filtered transmission electron microscopy. Our approach shows a promising possibility to use iron oxide nanoparticles, which are suitable for visualization and characterization at both the light- and electron-microscopic levels. From the Clinical Editor The authors report the first in vitro tests of a new ferrogel consisting of superparamagnetic iron oxide nanoparticles (SPIONs) and a Pluronic® F127 (PF127) copolymer for drug delivery in the inner ear, demonstrasting a promising possibility to use iron oxide nanoparticles, which are suitable for visualization and characterization at both the light- and electron-microscopic levels.

Cell specific targeting is an emerging field in nanomedicine. Homing of the multifunctional nanoparticles (MFNPs) is achieved by the conjugation of targeting moieties on the nanoparticle surface. The inner ear is an attractive target for new drug delivery strategies as it is hard to access and hearing loss is a significant worldwide problem. In this work we investigated the utility of a Nerve Growth Factor-derived peptide (hNgf_EE) functionalized nanoparticles (NPs) to target cells of the inner ear. These functionalized NPs were introduced to organotypic explant cultures of the mouse inner ear and to PC-12 rat pheochromocytoma cells. The NPs did not show any signs of toxicity. Specific targeting and higher binding affinity to spiral ganglion neurons, Schwann cells and nerve fibers of the explant cultures were achieved through ligand mediated multivalent binding to tyrosine kinase receptors and to p75 neurotrophin receptors. Unspecific uptake of NPs was investigated using NPs conjugated with scrambled hNgf_EE peptide. Our results indicate a selective cochlear cell targeting by MFNPs, which may be a potential tool for cell specific drug and gene delivery to the inner ear.

Different interests between mating partners regarding the fate of their gametes can lead to sexual conflicts in many species. Although these conflicts can sometimes be dealt with pre-copulatorily (e.g. by choosing with which partners to mate), they often extend beyond copulation. Post-copulatory sexual conflicts are expected to be particularly strong in simultaneous hermaphrodites because an individual may have to accept sperm in order to obtain an opportunity to donate sperm, reducing the effectiveness of pre-copulatory conflict resolution. The present study investigates the post-copulatory interactions between male and female sexual traits of a highly promiscuous simultaneous hermaphrodite, the free-living flatworm Macrostomum lignano. Using light and electron microscopy, we show the different levels of complexity of the sperm and the genitalia, and derive hypotheses about how the different traits may represent evolutionary responses to such sexual conflicts. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 370–383.

Primary ciliary dyskinesia (PCD) is an autosomal recessive inherited disease characterized by abnormal ciliary motion and impaired mucociliary clearance. The prevalence of PCD is approximately 1 : 15 000 - 1 : 20 000 in live births. Cilia dysfunction is also implicated in a wider spectrum of diseases due to impaired organ genesis and body symmetry. Cilia are highly conserved in animals and show complex structures containing more than 250 proteins for their formation. Recent studies have begun to locate the PCD genes in the genome and characterize functional mutations. Specific diagnosis of the ciliary dysfunction requires physiological measurements as well as light- and electron microscopy. Abnormalities in ciliary motion and ultrastructural studies can be performed with nasal mucosal epithelium.

The Labyrinthulomycota are a relatively poorly studied group of heterotrophic unicellular eukaryotes. They comprise three lineages, labyrinthulids, thraustochytrids, and aplanochytrids, which are all primarily marine organisms and considered to be important components of marine microbial communities. Recently a number of Labyrinthulomycota have been implicated as parasites of marine (but also terrestrial) plants and marine molluscs. Here we describe a new species of thraustochytrid, Thraustochytrium caudivorum sp. nov. that we have isolated from laboratory cultures of Macrostomum lignano (Rhabditophora, Macrostomorpha), a marine free-living flatworm. In these worms T. caudivorum can cause lesions, which start at the tip of the tail plate and which can lead to the dissolution of the posterior part of the animal. Although the worms can frequently cure these lesions and regenerate the lost parts, the lesions can also result in the complete dissolution of the animal. We describe this thraustochytrid based on pure agar cultures and infestations in the worm cultures. Moreover, we describe its pathological effects on the worms and its morphology using both light and electron microscopy. In addition, we report a phylogenetic analysis using a partial 18S rDNA sequence that allows us to place this new species within the thraustochytrids. Finally, we outline a protocol that allows to permanently remove the parasites from infested worm cultures. We conclude that thraustochytrids represent a novel group of parasites of free-living flatworms.

Oxidative stress to vascular endothelium plays an important role in cold ischemia-reperfusion (CIR) injury. We compared mitochondrial and plasma membrane integrity in human endothelial cells after 20-min exposure to 500 μM H 2 O 2 or 8-hr cold ischemia and simulated reperfusion. In both groups, plasma membrane integrity was maintained but respiration was significantly decreased, as measured by high-resolution respirometry. Uncoupling was more pronounced after H 2 O 2 exposure compared with CIR. After H 2 O 2 exposure, complex I respiration was significantly reduced, whereas CIR resulted additionally in a significant inhibition of complex II and IV respiration. Our results point to a partial overlap of the patterns of mitochondrial defects after H 2 O 2 -mediated and CIR injury. In this respect, H 2 O 2 exposure proved to be a useful model to study the mechanisms of CIR injury to human endothelial cells, whereas the full pattern of CIR injury could not be induced by a pulse of hydrogen peroxide exposure.

Die uber 1 200 Arten der Knorpelfische sind nur etwa 4 % aller heute lebenden Fischarten. Ihr knorpeliges Endoskelett kann zwar verkalken, wird aber nie zu Knochen umgebaut. Der Schadel besteht nur aus Neurocranium und Viscerocranium, ein Dermatocranium fehlt.

Unter den rezenten und fossilen Fischen sind die Sarcopterygier durch fleischige Loben an den paarigen Flossen charakterisiert. Fossil gehen sie bis in das Obere Silur (vor 420 Mio. Jahren) zuruck.

Der Bewegungsapparat bestimmt die Form des Wirbeltierkorpers. So lasst sich z. B. aus der Gestalt eines Fisches auf seine bevorzugte Schwimmweise schliesen (S. 56). Bei den aquatischen Schadeltieren dominiert die Fortbewegung mit axialem Antrieb; bei den meisten Tetrapoda findet sich eine Kombination aus axialem Antrieb und Bewegung durch Gliedmasen.

Die meisten Schadeltiere konnen die Wasser- und Ionenkonzentration ihres Innenmilieus regulieren, sind also im Hinblick auf ihren Ionenhaushalt weitgehend unabhangig von der Umgebung.

Die Actinopterygii bilden den uberwiegenden Teil der rezenten Fischfauna, wahrend die Fischformen der Sarcopterygii (S. 288) heute nur noch mit wenigen Arten der Dipnoi (Lungenfische) (S. 290) und Actinistia (Hohlstachler) (S. 296) vertreten sind.

Nervensysteme sind in der Regel die komplexesten Organe in tierischen Organismen, und die Nervensysteme der Cranioten (Schadeltiere) erreichen – von einigen Insekten und Cephalopoden abgesehen – den weitaus hochsten Grad der Komplexitat im Tierreich. Charakteristisch fur die Evolution der Craniotennervensysteme ist ihre Cerebralisierung am Vorderpol der Organismen mit zunehmender Gehirngrose und Zellzahl, neuronaler Vernetzung und dem verbesserten Vermogen Information zu speichern, zu koordinieren und mit komplexen Reaktionsmustern zu antworten.

Die kieferlosen Cyclostomata umfassen die beiden Taxa Myxinoida und Petromyzontida. Das auffallendste Strukturelement beider Gruppen ist der sog. Zungenapparat im Mundboden. Im Mundbereich sind Hornzahnchen ausgebildet (Abb. 181, 192). Bei beiden Taxa fehlen paarige Extremitaten und Gurtelbildungen vollig; die zeitlebens persistierende biegeelastische Chorda dorsalis fungiert als Axialskelett.

Generell vermehren sich Schadeltiere geschlechtlich (sexuell), und die Geschlechter sind uberwiegend getrennt (gonochoristisch).

Alle Lebewesen mussen sich gegen Eindringlinge wehren. Ihre Abwehrmechanismen wirken auf verschiedenen Ebenen, von ubergeordneten Feindvermeidungsstrategien und Putzverhalten bis hin zu molekularen Erkennungs- und Totungsmechanismen.

Background. Protection of vascular endothelium is a critical factor in organ preservation for transplantation. This study aims at a morphological assessment of endothelial cell injury in a comparison of storage solutions, using a cell culture model of cold preservation and rewarming. Materials and methods. Human umbilical vein endothelial cells (HUVEC) were cultured in monolayer and exposed to hypothermic storage in University of Wisconsin (UW), histidine‐tryptophane‐ ketoglutarate (HTK), and EuroCollins solutions for 6 h and subsequent rewarming for 30 min or 6 h. Alterations of subcellular structures and cell‐ cell contacts were analyzed by transmission electron microscopy (TEM) and light microscopic assessment after actin and nuclear staining. Results. Structural alterations of mitochondria, endoplasmic reticulum, nuclei, and cytoskeletal fibers as well as disruption of intercellular contacts were found after cold storage in HTK and EuroCollins solutions. In contrast, storage in UW solution resulted in minimum changes of stress fibers only. A rapid rearrangement of structural alterations was achieved during rewarming in cell culture medium in all experimental groups. Conclusions. Preservation of endothelial cell structure is best achieved by UW solution. Ultrastructural cell damage is a direct consequence of hypothermic storage and is fully reversible during rewarming after short storage times. © 1999 Academic Press

Human spiral ganglion (SG) neurons show remarkable survival properties and maintain electric excitability for a long time after complete deafness and even separation from the organ of Corti, features essential for cochlear implantation. Here, we analyze and compare the localization and distribution of gap junction (GJ) intercellular channels and connexin 43 (Cx43) in cells surrounding SG cell bodies in man and guinea pig by using transmission electron microscopy and confocal immunohistochemistry. GJs and Cx43 expression has been recognized in satellite glial cells (SGCs) in non-myelinating sensory ganglia including the human SG. In man, SG neurons can survive as mono-polar or “amputated” cells with unbroken central projections following dendrite degeneration and consolidation of the dendrite pole. Cx43-mediated GJ signaling between SGCs is believed to play a key role in this “healing” process and could explain the unique preservation of human SG neurons and the persistence of cochlear implant function.

Schleimaale leben in Bodennahe bzw. im Schlamm eingegraben in allen Ozeanen bis in 2500 m Tiefe, bevorzugt in mehr als 30 m Tiefe in kustennahen Bereichen der gemasigten Breiten. Geringere Salinitat und vor allem Wassertemperaturen uber 20°C sind limitierende Faktoren fur ihr Vorkommen, das sich daher in warmeren Zonen auf grosere Tiefen beschrankt. Auch vom East Pacific Rise ist seit kurzem eine neue Art der Gattung Eptatretus bekannt (S. 198).

Questions as to the critical stress factor and primary targets of cold ischemia/reperfusion (CIR) injury were addressed by comparing mitochondrial defects caused by (1) CIR injury and (2) intracellular Ca2+ overload. CIR was simulated in transformed human umbilical vein endothelial cell cultures (tEC) by 8 h cold anoxia in University of Wisconsin solution and reoxygenation at 37 degrees C. Intracellular Ca2+ concentrations were changed by permeabilization of suspended cells with digitonin in culture medium (RPMI, 0.4 mM Ca2+). Binding of free Ca2+ by ethylene glycol-bis(beta-aminoethylether)-N,N,N',N'-tetraacetic acid in RPMI or mitochondrial incubation medium served as controls. Extracellular Ca2+ protected the cell membrane against permeabilization. Mitochondrial functions were determined before and after permeabilization of the cell membrane. After CIR, mitochondrial respiratory capacity declined, but oxygen consumption remained coupled to adenosine triphosphate (ATP) production. In contrast, Ca2+ overload caused uncoupling of mitochondrial respiration. High intracellular Ca2+ overload, therefore, does not reproduce cold ischemia/reperfusion injury in endothelial cells.

0 RGAN PRESERVATION under hypothermic ischemia is enhanced by storage solutions that protect the vascular endothelium from ischemia-reperfusion injury. Ischemia-reperfusion injury leads to primary graft failure and chronic rejection, and is commonly assessed by measuring endothelial activation and damage of the endothelial plasma membrane. However, corresponding primary intracellular events are little understood compared with the secondary cytokine/adhesion molecule cascade and inflammatory responses.‘-* Because protection of intracellular and cell membrane function is fundamental for further improvement of organ preservation, we developed highresolution respirometry as a sensitive diagnostic test for mitochondrial and plasma membrane competence.3 Whereas the plasma membrane remained impermeable after clinically relevant cold storage times of 8 hours and 20