Residual Mesenchyme in Temporal Bones of Children

The role of mesenchyme in the temporal bone is still poorly understood. A microscopic study of residual mesenchyme was undertaken in temporal bones of children from birth to 5 years of age. Residual mesenchyme was found to be located in the mastoid antrum and epitympanum more often than in the mesotympanum. The amount of mesenchymal tissue remaining in the temporal bones decreased with increasing age. Persistence of mesenchyme in the temporal bone was related to congenital morphologic ear anomalies and syndromes. There was also an association evident with pulmonary disease, but not with congenital heart defects. Persistent mesenchyme was also found to be significantly associated with chronic middle ear inflammation, and in cases of unilateral otitis media the ear with otitis media had more residual mesenchyme than the non-otitis media ear.     

Keratitis caused by Trachipleistophora anthropopthera

We report a case of intrastromal keratitis in a 42-year-old male with underlying human immunodeficiency virus-1 infection. Numerous microsporidial spores were found from corneal biopsy. Ultrastructural studies of corneal tissues revealed dimorphic sporophorous vesicles containing characteristic spores belonging to Trachipleistophora anthropopthera. Infection could be controlled by penetrating keratoplasty but not by topical fumagillin and systemic albendazole per se. This is the first report of human keratitis caused by this organism.     

Serotonin inhibits neuronal excitability by activating two-pore domain k+ channels in the entorhinal cortex

The entorhinal cortex (EC) is regarded as the gateway to the hippocampus; the superficial layers (layers I-III) of the EC convey the cortical input projections to the hippocampus, whereas deep layers of the EC relay hippocampal output projections back to the superficial layers of the EC or to other cortical regions. The superficial layers of the EC receive strong serotonergic projections from the raphe nuclei. However, the function of serotonin in the EC is still elusive. In the present study, we examined the molecular and cellular mechanisms underlying serotonin-mediated inhibition of the neuronal excitability in the superficial layers (layers II and III) of the EC. Application of serotonin inhibited the excitability of stellate and pyramidal neurons in the superficial layers of the EC by activating the TWIK-1 type of the two-pore domain K(+) channels. The effects of 5-HT were mediated via 5-HT(1A) receptors and required the function of Galpha(i3) subunit and protein kinase A. Serotonin-mediated inhibition of EC activity resulted in an inhibition of hippocampal function. Our study provides a cellular mechanism that might at least partially explain the roles of serotonin in many physiological functions and neurological diseases.     

Bestrophin 1 is indispensable for volume regulation in human retinal pigment epithelium cells

In response to cell swelling, volume-regulated anion channels (VRACs) participate in a process known as regulatory volume decrease (RVD). Only recently, first insight into the molecular identity of mammalian VRACs was obtained by the discovery of the leucine-rich repeats containing 8A (LRRC8A) gene. Here, we show that bestrophin 1 (BEST1) but not LRRC8A is crucial for volume regulation in human retinal pigment epithelium (RPE) cells. Whole-cell patch-clamp recordings in RPE derived from human-induced pluripotent stem cells (hiPSC) exhibit an outwardly rectifying chloride current with characteristic functional properties of VRACs. This current is severely reduced in hiPSC-RPE cells derived from macular dystrophy patients with pathologic BEST1 mutations. Disruption of the orthologous mouse gene (Best1^−/−) does not result in obvious retinal pathology but leads to a severe subfertility phenotype in agreement with minor endogenous expression of Best1 in murine RPE but highly abundant expression in mouse testis. Sperm from Best1^−/− mice showed reduced motility and abnormal sperm morphology, indicating an inability in RVD. Together, our data suggest that the molecular identity of VRACs is more complex—that is, instead of a single ubiquitous channel, VRACs could be formed by cell type- or tissue-specific subunit composition. Our findings provide the basis to further examine VRAC diversity in normal and diseased cell physiology, which is key to exploring novel therapeutic approaches in VRAC-associated pathologies.Tight regulation of cell volume is fundamental to proper cell function and survival. In general, rapid water influx across cell membranes leads to cell swelling, which in turn activates net efflux of K⁺ and Cl⁻, thereby triggering the release of osmotically obligated water from the cell. Essential to this process is the activation of a current primarily carried by chloride ions (I_swell). This current is gated by volume-regulated anion channels (VRACs) returning the cell to a controlled state of homeostatic integrity, a complex mechanism commonly referred to as regulatory volume decrease (RVD) (1, 2). Although VRACs share common features in almost all cell types, it is unclear whether there is one ubiquitous channel or a diversity of chloride channels with slightly differing functional properties. In this context, three families of proteins—the Ca²⁺- and/or volume-sensitive anoctamins, bestrophins, and the recently discovered LRRC8s—are presently at the center of interest (3–7).Bestrophin 1 (BEST1), a member of the human bestrophin family of four paralogous genes, encodes an integral membrane protein strongly expressed in the human retinal pigment epithelium (RPE) (8). Mutations in BEST1 have been associated with various macular dystrophies most prominently represented by Best disease (BD), a central retinopathy with autosomal dominant inheritance but variable penetrance and expressivity (9, 10). Key features of BD pathology include a striking lipofuscin accumulation in the macular RPE (11) and an abnormal light peak (LP)/dark trough ratio in the electro-oculogram (EOG) reflective of an impaired RPE (12). The abnormalities in the LP were suggested to be compatible with a function of BEST1 as a Ca²⁺-activated Cl⁻ channel (CaCC) (13, 14).Addressing BEST1 function, several studies have suggested a role of the protein in distinct basic cellular processes such as Ca²⁺ homeostasis, neurotransmitter release, and cell volume regulation. These studies mostly relied on BEST1 overexpression in HEK293 cells or conducted in vitro experiments with isolated cells from existing Best1-deficient mouse lines. In summarizing these data, BEST1 was shown to be (i) a calcium sensor localized to the endoplasmic reticulum (ER) of mouse RPE (15), (ii) an intracellular Cl⁻ channel activating anoctamin 1 (ANO1) located at the plasma membrane of mouse trachea (5), (iii) a modulator of voltage-gated Ca²⁺ channels in murine RPE (16), and (iv) a channel for tonic GABA or slow glutamate release in mouse glia cells and astrocytes (17, 18). To date, the functional role of Best1 has not been determined in the mouse testis, the site of highest endogenous Best1 expression in the mouse (19). In addition, using patient-derived hiRPE cells, the role of BEST1 in mediating ER calcium release and/or uptake was shown (20). In contrast, two independent studies in S2R+ cells from Drosophila melanogaster strongly suggested the invertebrate Drosophila Best1 (dBest1) to act as a volume-regulated chloride channel but with biophysical characteristics clearly distinct from a vertebrate VRAC (3, 21). By small interfering RNA (siRNA)-mediated knockdown of BEST1 in HEK293 cells (6) and mouse Best1 (mBest1) gene disruption in murine peritoneal macrophages (22), two studies could not show a functional effect of BEST1 on I_swell, thus questioning this protein as a candidate for mammalian VRAC in these cell types. Instead, two studies identified the LRRC8A gene as an essential component of a VRAC in various cultured cell lines (6, 7). In these latter studies, the authors propose a scenario where LRRC8A and the isoforms LRRC8B to LRRC8E form variable cell type-specific hexamers, explaining the variability of VRAC properties in different cell types.Together, the rather disparate reports on BEST 1 function underscore the need to further clarify its role in mammalian VRACs. To this end, we focused on two tissues with strong endogenous BEST1 protein expression—namely, human RPE (8) and mouse sperm (19). Major insight into BEST1 function was gained from (i) RPE cell culture models established via hiPSC technology from a healthy donor and two macular dystrophy patients with established pathologic mutations in BEST1 and (ii) a mouse strain deficient for Best1, the murine ortholog of the human BEST1 gene. When exposed to hypo-osmotic challenge, both the mutant hiPSC-RPE cells and Best1-deficient mouse spermatozoa exhibited severe phenotypes, suggesting BEST1 as a crucial component of VRAC function in these cell types. In addition, membrane rupture experiments and voltage-clamp recordings in oocytes from Xenopus laevis, coexpressing aquaporin-1 (AQP1) and BEST1 from mouse and human, respectively, demonstrated identical functional properties of the mammalian BEST1 orthologs.     

A Comparison of 3 Quantitative Radiographic Measurement Methods for Root Development Measurement in Regenerative Endodontic Procedures

Introduction

The outcomes of an immature tooth with necrotic pulp treated with regenerative endodontic procedures (REPs) were assessed clinically and radiographically. Root maturation is an important outcome of REPs, and several radiographic measurement methods have been used to measure this. The aim of this study was to compare radiographic measurement methods, measuring root maturation in immature teeth with necrotic pulp treated with REPs.

A Plant-Derived Hydrolysable Tannin Inhibits CFTR Chloride Channel: A Potential Treatment of Diarrhea

Purpose  

The present study examined the effects and mechanisms of actions of penta-m-digalloyl-glucose (PDG), a hydrolysable tannin extracted from Chinese gallnut, on cystic fibrosis transmembrane conductance regulator protein (CFTR).     

Text2Quit: results from a pilot test of a personalized, interactive mobile health smoking cessation program

Text messaging programs on mobile phones have shown some promise in helping people quit smoking. Text2Quit is an automated, personalized, and interactive mobile health program that sends text messages and e-mails timed around a participant's quit date over the course of 3 months. The text messages include pre- and post-quit educational messages, peer ex-smoker messages, medication reminders and relapse messages, and multiple opportunities for interaction. Study participants were university students (N = 23) enrolled in the Text2Quit program. Participants were surveyed at baseline and at 2 and 4 weeks after enrollment. The majority of participants agreed that they liked the program at 2 and 4 weeks after enrollment (90.5% and 82.3%, respectively). Support for text messages was found to be moderate and higher than that of the e-mail and web components. Of participants, 75% reported reading most or all of the texts. On average, users made 11.8 responses to the texts over a 4-week period, although responses declined after the quit date. The interactive feature for tracking cigarettes was the most used interactive feature, followed by the craving trivia game. This pilot test provides some support for the Text2Quit program. A future iteration of the program will include additional tracking features in both the pre-quit and post-quit protocols and an easier entry into the not-quit protocol. Future studies are recommended that identify the value of the interactive and personalized features that characterize this program.