Electrophysiological analysis of mammalian cells expressing hERG using automated 384-well-patch-clamp

BACKGROUND: An in vitro electrophysiological assay system, which can assess compound effects and thus show cardiotoxicity including arrhythmia risks of test drugs, is an essential method in the field of drug development and toxicology. METHODS: In this study, high-throughput electrophysiological recordings of human embryonic kidney (HEK 293) cells and Chinese hamster ovary (CHO) cells stably expressing human ether-a-go-go related gene (hERG) were performed utilizing an automated 384-well-patch-clamp system, which records up to 384 cells simultaneously. hERG channel inhibition, which is closely related to a drug-induced QT prolongation and is increasing the risk of sudden cardiac death, was investigated in the high-throughput screening patch-clamp system. RESULTS: In the automated patch-clamp measurements performed here, K(v) currents were investigated with high efficiency. Various hERG channel blockers showed concentration-dependent inhibition, the 50 % inhibitory concentrations (IC(50)) of those blockers were in good agreement with previous reports. CONCLUSIONS: The high-throughput patch-clamp system has a high potential in the field of pharmacology, toxicology, and cardiac physiology, and will contribute to the acceleration of pharmaceutical drug development and drug safety testing

Regenerative Therapies Using Cell Sheet-Based Tissue Engineering for Cardiac Disease

At present, cardiac diseases are a major cause of morbidity and mortality in the world. Recently, a cell-based regenerative medicine has appeared as one of the most potential and promising therapies for improving cardiac diseases. As a new generational cell-based regenerative therapy, tissue engineering is focused. Our laboratory has originally developed cell sheet-based scaffold-free tissue engineering. Three-dimensional myocardial tissue fabricated by stacking cardiomyocyte sheets, which are tightly interconnected to each other through gap junctions, beats simultaneously and macroscopically and shows the characteristic structures of native heart tissue. Cell sheet-based therapy cures the damaged heart function of animal models and is clinically applied. Cell sheet-based tissue engineering has a promising and enormous potential in myocardial tissue regenerative medicine and will cure many patients suffering from severe cardiac disease. This paper summarizes cell sheet-based tissue engineering and its satisfactory therapeutic effects on cardiac disease

<ORIGINAL>Combined Effects of Erbium : YAG laser and Fluoride Application on Acid Resistance of Tooth dentin in vitro

This study examined the inhibition of dentin demineralization in initial caries with Er : YAG laser irradiation only and laser irradiation combined with fluoride application. Dentin blocks were prepared from the roots of bovine incisors and pretreated with one of the following five procedures : A) untreated, B) Er : YAG laser irradiation for 5min at 50mJ/pulse, C) APF gel application for 5min, D) Er : YAG laser followed by APF application for 5min,and E) APF treatment for 5min followed by Er : YAG laser irradiation. Subsequently the samples were demineralized in a 0.1M lactic acid gel (pH5.0) containing 6wt% CMC at 37℃ for 2 weeks. The mineral distributions in the dentin surfaces were assessed quantitatively by transversal microradiography (TMR) and videodensitometry. The mineral parameter values were not significantly different for samples with and without laser treatment at p=0.05, as tested by paired t-tests. The present results suggest that the progress of demineralization in dentin lesions is not effectively inhibited by the single treatment with laser irradiation. Combined Er : YAG laser and APF treated samples had the highest acid resistance with significantly lower lesion depth (ld) and mineral loss (ΔZ) values lower even than the APF treated samples

Infection of mesangial cells with HIV and SIV: Identification of GPR1 as a coreceptor

Infection of mesangial cells with HIV and SIV: Identification of GPR1 as a coreceptor.BackgroundMesangial cells are an important component of the glomerulus. Dysfunction of mesangial cells is thought to be involved in the development of human immunodeficiency virus type 1 (HIV-1)-associated nephropathy (HIVAN). HIVAN is a structural renal failure frequently observed in patients with acquired immune deficiency syndrome. However, the susceptibility of mesangial cells to HIV-1 is disputable. More than ten G protein-coupled receptors, including chemokine receptors, have been shown to act as HIV-1 coreceptors that determine the susceptibilities of cells to HIV-1 strains with specific cell tropisms.MethodsWe examined the susceptibility of mesangial cells to various HIV-1, HIV type 2 (HIV-2) and simian immunodeficiency virus (SIV) strains. Expression of CD4 and HIV/SIV coreceptors was examined by Western blotting and polymerase chain reaction.ResultsMesangial cells were found to be susceptible to HIV-1 variant and mutants that infect brain-derived cells, but highly resistant to T-tropic (X4), M-tropic (R5) or dual-tropic (X4R5) HIV-1 strains. In addition, mesangial cells were also susceptible to HIV-2 and SIV strains that infect the brain-derived cells. Among HIV/SIV coreceptors we tested, the expression of GPR1 mRNA was detected in mesangial cells. Expression of CD4 mRNA and protein was also detected in them. Mesangial cells and GPR1-transduced CD4-positive cells showed similar susceptibilities to the HIV-1 variant and mutants and HIV-2 and SIV strains.ConclusionsCD4 and GPR1 mRNAs were detected in mesangial cells. Mesangial cells were susceptible to HIV/SIV strains that use GPR1 as a coreceptor. Our findings suggest that an orphan G protein-coupled receptor, GPR1, is a coreceptor expressed in mesangial cells. It remains to be investigated whether the interaction of mesangial cells with specific HIV-1 strains through GPR1 plays a role in the development of HIVAN

Application of the Erbium : YAG Laser to Cavity preparation for Cast Metal Inlay Restoration

Recently, an Er : YAG laser has been developed for dental hard tissue cutting. This laser has been usually used for cavity preparation of composite resin restorations, but not for cast metal inlays, because it is difficult to create a cavity form which ensures retention form and convenience form. An experimental chisel shaped contact tip for use in cavity preparation for cast metal inlays was developed. This tip has specified irradiation energy distribution characteristic and the usefulness of this tip in inlay cavity reparation was examined. The tooth cutting efficiency was determined in extracted human and bovine teeth, and the irradiated sites were observed with SEM. The experimental tip cuts dentin as well as conventional tips while enamel cutting is poorer than with the conventional tip. It was possible to obtain flat properly inclined dentin walls in the cavity preparation. It is suggested that inlay cavity preparation is possible using the experimental chisel shaped contact tip

Multiple rectal carcinoids with diffuse ganglioneuromatosis

BACKGROUND: Rectal carcinoids comprise only about 1% of all anorectal neoplasms. In addition, ganglioneuroma of the gastrointestinal tract is a rare tumor composed ganglion cells, nerve fibers, and supporting cells. Multiple carcinoid tumors with diffuse ganglioneuromatosis limited to the rectum are quite unusual. CASE PRESENTATION: A 69-year-old man was referred to us because of about 100 small submucosal rectal tumors. He underwent abdominoperineal resection. Pathology revealed carcinoid tumors for about 30 submucosal nodules and diffuse ganglioneuromotosis. To date (6 months later) he remains well with no recurrence. CONCLUSION: Although the optimal treatment for the multiple rectal carcinoids remains to be clearly established, it is believed that not all patients with multiple rectal carcinoids (measuring less than 1 cm in diameter) need to have a radical operation. However, the treatment plan for each case should be individualized and a careful follow-up is mandatory

A cold seep triggered by a hot ridge subduction

The Chile Triple Junction, where the hot active spreading centre of the Chile Rise system subducts beneath the South American plate, offers a unique opportunity to understand the influence of the anomalous thermal regime on an otherwise cold continental margin. Integrated analysis of various geophysical and geological datasets, such as bathymetry, heat flow measured directly by thermal probes and calculated from gas hydrate distribution limits, thermal conductivities, and piston cores, have improved the knowledge about the hydrogeological system. In addition, rock dredging has evidenced the volcanism associated with ridge subduction. Here, we argue that the localized high heat flow over the toe of the accretionary prism results from fluid advection promoted by pressure-driven discharge (i.e., dewatering/discharge caused by horizontal compression of accreted sediments) as reported previously. However, by computing the new heat flow values with legacy data in the study area, we raise the assumption that these anomalous heat flow values are also promoted by the eastern flank of the currently subducting Chile Rise. Part of the rift axis is located just below the toe of the wedge, where active deformation and vigorous fluid advection are most intense, enhanced by the proximity of the young volcanic chain. Our results provide valuable information to current and future studies related to hydrothermal circulation, seismicity, volcanism, gas hydrate stability, and fluid venting in this natural laboratory

Testicular Torsion in Undescended Testis : A Case Report and View of Sixty-two Cases in Japan

A 7-year-old boy with cerebral palsy was presented with a progressively enlarging tender, left inguinal mass. Examination revealed absence of the left testis in the scrotal sac. The left testis was palpable in the left superficial inguinal pouch. The right testis was normaly palpable in the right scrotum. A diagnosis of a torsion in the undescended left testis was confirmed by exploratory surgery. Orchidectomy of the left testis was performed and the remainder of the patient\u27s course was uneventful. We presented this case to describe the clinical features of testicular torsion in the undescended testis with a review of 62 cases in Japan. Specific emphasis was placed on the incidence, relationship of cerebral palsy to torsion, diagnosis, and treatment of testicular torsion in cryptorchidism

Membrane proteins Bqt3 and -4 anchor telomeres to the nuclear envelope to ensure chromosomal bouquet formation

A screen identifies two more bouquet proteins required for meiotic telomere clustering: Bqt4 anchors the telomeres, whereas Bqt3 protects Bqt4 from degradation