A bezoar is a mass formed because of the accumulation of indigestible material in the stomach and/or small intestine. Bezoars are rare but occasionally occur with acute abdomen findings. Bezoars form as a result of changes in the gastrointestinal system anatomy and physiology and repetitive exposure to the ingested material. These materials can include vegetables with high fiber content (phytob...

The mammalian cochlea depends on an amplification process for its sensitivity and frequency-resolving capability. Outer hair cells are responsible for providing this amplification. It is usually assumed that the membrane-potential-driven somatic shape changes of these cells are the basis of the amplifying process. It is of interest to see whether mechanical reactance changes of the cells might ...

Sensory hair cell ribbon synapses respond to graded stimulation in a linear, indefatigable manner, requiring that vesicle trafficking to synapses be rapid and nonrate-limiting. Real-time monitoring of vesicle fusion identified two release components. The first was saturable with both release rate and magnitude varying linearly with Ca(2+), however the magnitude was too small to account for sust...

Cochlear outer hair cells (OHCs) express alpha9 nACh receptors and are contacted by descending, predominately cholinergic, efferent fibers originating in the CNS. Mice carrying a null mutation for the nACh alpha9 gene were produced to investigate its role(s) in auditory processing and development of hair cell innervation. In alpha9 knockout mice, most OHCs were innervated by one large terminal ...

Cochlear synaptopathy can result from various insults, including acoustic trauma, aging, ototoxicity, or chronic conductive hearing loss. For example, moderate noise exposure in mice can destroy up to ∼50% of synapses between auditory nerve fibers (ANFs) and inner hair cells (IHCs) without affecting outer hair cells (OHCs) or thresholds, because the synaptopathy occurs first in high-threshold A...

The compressive nonlinearity of cochlear signal transduction, reflecting outer-hair-cell function, manifests as suppressive spectral interactions; e.g., two-tone suppression. Moreover, for broadband sounds, there are multiple interactions between frequency components. These frequency-dependent nonlinearities are important for neural coding of complex sounds, such as speech. Acoustic-trauma-indu...

Inner ear hair cell afferent fiber synapses are capable of transferring 20 information at high rates, for long periods of time with extraordinary fidelity. As at other 21 sensory synapses, hair cells rely on graded receptor potentials and unique vesicle 22 trafficking and release properties of ribbon synapses to relay intensity information. 23 Postsynaptic recordings from afferent fibers of the...

One feature of neuronal discharge proposed to play a role in coding temporal information is the relative refractory period that follows each action potential. In neurons innervating hair cells, there is an extended refractory period that can last </=100 ms. We have taken a pharmacological approach to examine the extended refractory period in the Xenopus lateral line organ. We show that each act...

Somatic sensory neurons of the dorsal root ganglia are necessary for a large part of our mechanosensory experience. However, we only have a good knowledge of the molecules required for mechanotransduction in simple invertebrates such as the nematode Caenorhabiditis elegans. In C. elegans, a number of so-called mec genes have been isolated that are required for the transduction of body touch. On...