Renal Glomerular Mitochondria Function in Salt-Sensitive Hypertension.

Salt-sensitive (SS) hypertension is accompanied with an early onset of proteinuria, which results from the loss of glomerular podocytes. Here, we hypothesized that glomerular damage in the SS hypertension occurs in part due to mitochondria dysfunction, and we used a unique model of freshly isolated glomeruli to test this hypothesis. In order to mimic SS hypertension, we used Dahl SS rats, an established animal model.

Macrophage-Mediated Glial Cell Elimination in the Postnatal Mouse Cochlea.

Hearing relies on the transmission of auditory information from sensory hair cells (HCs) to the brain through the auditory nerve. This relay of information requires HCs to be innervated by spiral ganglion neurons (SGNs) in an exclusive manner and SGNs to be ensheathed by myelinating and non-myelinating glial cells. In the developing auditory nerve, mistargeted SGN axons are retracted or pruned and excessive cells are cleared in a process referred to as nerve refinement.

2'-hydroxy C16-ceramide induces apoptosis-associated proteomic changes in C6 glioma cells.

Ceramide is a bioactive sphingolipid involved in regulation of numerous cell signaling pathways. Evidence is accumulating that differences in ceramide structure, such as N-acyl chain length and desaturation of sphingoid base, determine the biological activities of ceramide. Using synthetic (R)-2'-hydroxy-C16-ceramide, which is the naturally occurring stereoisomer, we demonstrate that this ceramide has more potent pro-apoptotic activity compared to its (S) isomer or non-hydroxylated C16-ceramide.

Chronic reduction of endocochlear potential reduces auditory nerve activity: further confirmation of an animal model of metabolic presbyacusis.

Gerbils aged in quiet show a decline of the endocochlear potential (EP) and elevated auditory nerve compound action potential (CAP) thresholds. However, establishing a direct relationship between an age-related reduction in the EP and changes in the activities of primary auditory neurons is difficult owing to the complexity of age-related histological changes in the cochlea. To address this issue, we developed a young gerbil model of "metabolic" presbyacusis that uses an osmotic pump to deliver furosemide into the round window niche for 7 days, resulting in a chronically reduced EP.

Mitochondria-activated cisternae generate the cell specific vesicles in auditory hair cells.

A dense population of vesicles largely fills the infranuclear compartment of gerbil inner hair cells (IHCs). Although the nature of the cargo in these vesicles has not been determined, the absence of a Golgi apparatus from the IHC's basal compartment suggests that the vesicles lack the glycosylated protein that Golgi cisternae would provide. Instead, they likely possess neurotransmitter and function as synaptic vesicles.

Identification of ClC-2 and CIC-K2 chloride channels in cultured rat type IV spiral ligament fibrocytes.

Voltage-gated chloride channels (ClCs) are important mediators of cellular ion homeostasis and volume regulation. In an earlier study, we used immunohistochemical, Western blot, and reverse transcriptase PCR (RT-PCR) approaches to identify ClC-K variants in types II, IV, and V fibrocytes of the rodent spiral ligament. We have now confirmed the expression of ClC-K2 in these cells by in situ hybridization.

Topical application of mitomycin C to the middle ear is ototoxic in the gerbil.

Hypothesis: Mitomycin C is ototoxic when applied topically to the structures of the middle ear.

Background: Mitomycin C is a topically applied medication widely used in a variety of surgical procedures to prevent excessive scar tissue formation. Its safety for use during otologic procedures has not been fully evaluated.

Contribution of bone marrow hematopoietic stem cells to adult mouse inner ear: mesenchymal cells and fibrocytes.

Bone marrow (BM)-derived stem cells have shown plasticity with a capacity to differentiate into a variety of specialized cells. To test the hypothesis that some cells in the inner ear are derived from BM, we transplanted either isolated whole BM cells or clonally expanded hematopoietic stem cells (HSCs) prepared from transgenic mice expressing enhanced green fluorescent protein (EGFP) into irradiated adult mice. Isolated GFP(+) BM cells were also transplanted into conditioned newborn mice derived from pregnant mice injected with busulfan (which ablates HSCs in the newborns).

Presence of surfactant lamellar bodies in normal and diseased sinus mucosa.

Background: Pulmonary surfactant originates from phospholipid lamellar bodies secreted from the type II epithelial cell of the alveolus. In the lower airway, surfactant optimizes surface tension and oxygen exchange, decreases mucus viscosity and aids in mechanical elimination of inhaled pathogens. In addition to the lung, lamellar bodies have been identified in many other cell types throughout the human body.

Ultrastructure indicative of ion transport in tectal, Deiters, and tunnel cells: differences between gerbil and chinchilla basal and apical cochlea.

Ultrastructural examination revealed an epithelium of about five tectal cells (TCs) roofing the outer tunnel (OT) in the mid to upper, but not the basal, region of gerbil and chinchilla cochlea. Structures in TCs that are apparently specialized for retrieval of K(+) released into tunnel fluid from outer hair cells (OHCs) include surface fimbriae in the gerbil and canalicular reticulum in the chinchilla. A tunnel roof of organelle-rich TCs appeared to be better equipped for ion resorption than a roof composed of organelle-poor Hensen cells (HCs).