Low-voltage-activated potassium channels underlie the regulation of intrinsic firing properties of rat vestibular ganglion cells

Individual primary vestibular afferents exhibit spontaneous activity the regularity of which can vary from regular to irregular. Different aspects of vestibular responsiveness have been associated with this dimension of regularity of resting discharge. Isolated rat vestibular ganglion cells (VGCs) showed heterogeneous intrinsic firing properties during sustained membrane depolarization: some neurons exhibited a strong adaptation generating just a single or a few spikes (phasic type), whereas other neurons showed moderate adaptation or tonic firing (tonic type). Tonic discharging VGCs were rare at postnatal days 5–7 and increased up to 60% of neurons during postnatal 2–3 wk. To explore the major factors responsible for the discharge regularity of primary vestibular afferents, we investigated the contribution of K⁺ channels to the firing properties of isolated rat VGCs. Phasic firing became tonic firing in the presence of 4-aminopyridine or -dendrotoxin, indicating that Kv1 potassium channels control the firing pattern of the phasic VGCs. Tetraethylammonium decreased the number of spikes during step current stimuli in all types. Blockade of Ca²⁺-activated K⁺ channels decreased the number of spikes in tonic VGCs. Our results suggest that Kv1 channels are critical both in determining the pattern of spike discharge in rat vestibular ganglion neurons and in their proportional change during maturation.     

Phenotypic grouping of 141 BmNPVs lacking viral gene sequences

We constructed a series of gene knockout BmNPVs (KOVs) for each of 141 genes (Gomi et al., 1999; Katsuma et al., 2011) using the BmNPV T3 bacmid system (Ono et al., 2007) and lambda red recombination system (Datsenko and Wanner, 2000). In a subsequent analysis of the properties needed for infection using a marker gene, egfp (enhanced green fluorescent protein gene), inserted into the polyhedrin locus, the knockout viruses (KOVs) were subdivided into four phenotypic types, A to D. Type-A (86 KOVs) showed the ability to expand infections equivalent to the control while type-B (8 KOVs) spread infections more slowly. Type-C (37 KOVs) expressed egfp in transfected-BmN cells but the production of infectious viruses was not observed. Type-D (10 KOVs) showed no ability to express egfp even in the transfection experiments. KOVs lacking genes (pkip (Bm15), gp41 (Bm66), bro-d (Bm131), Bm20, 48, 65, 91, 93, or 101) previously identified as being essential, were placed in the viable type-A and B categories.     

Balloon occlusion retrograde transvenous obliteration for inferior mesenteric vein-systemic shunt

Two cases of portosystemic encephalopathy caused by an inferior mesenteric vein (IMV)-internal iliac vein shunt and an IMV-renal vein shunt are presented. IMV and systemic varicosity consisted of a first functional segment, a stagnant segment, and a second functional segment. Both patients underwent balloon occlusion retrograde transvenous obliteration (BRTO), using a microcatheter, to occlude the stagnant segment selectively. Although transient portal vein thrombosis was observed in case 1 and aggravation of esophageal varices was observed in case 2, these complications were tolerable. Following BRTO, the portosystemic encephalopathy in both cases resolved, and serum ammonia levels, although elevated, remained within the normal range.     

Induction of Cytotoxic T Lymphocytes from Peripheral Blood of Human Histocompatibility Antigen (HLA)-A31+ Gastric Cancer Patients by in vitro Stimulation with Antigenic Peptide of Signet Ring Cell Carcinoma

Antigenic peptides have been used as a cancer vaccine in melanoma patients and have led to a drastic regression of metastatic tumors. However, few antigens have been identified in non-melanoma tumors. We recently purified a new natural antigenic peptide, designated F4.2, by biochemical elution from a human gastric signet cell carcinoma cell line and showed that it is recognized by an autologous human histocompatibility antigen (HLA)-A31-restricted cytotoxic T lymphocyte (CTL) clone. Here we describe in vitro induction of F4.2-specific CTLs from peripheral blood T lymphocytes of HLA-A31⁺ gastric cancer patients. The T cells of seven HLA-A31⁺ patients with gastric cancers were stimulated in vitro by F4.2-pulsed autologous dendritic cells which had been induced from peripheral blood of each patient by incubation in the presence of granulocyte macrophage colony-stimulating factor (GM-CSF) and IL-4. We tested the cytotoxicity of the T cells against F4.2-loaded C1R-A *31012 by a 6-h ⁵¹Cr release assay after 3 stimulations with F4.2-pulsed dendritic cells. F4.2-specific cytotoxicity was detectable in the stimulated T cells from two of the seven HLA-A31⁺ patients. Further, both F4.2-specific CTLs also lysed the gastric cancer cell line, HST-2, from which F4.2 was derived. These results suggest that F4.2 peptide may be useful as an HLA-A31-restricted peptide vaccine in certain patients with gastric cancer.     

Prostaglandin E(2) receptor EP(4)-selective agonist (ONO-4819) increases bone formation by modulating mesenchymal cell differentiation

Prostaglandin E₂ (PGE₂) positively regulates bone resorption and formation mainly mediated through the EP₄ receptor, a subtype of PGE₂ receptors. ONO-4819, an EP₄ receptor-selective agonist, has been shown to increase bone volume, density, and strength; however, the mechanism of these effects has yet to be fully elucidated. To explore this matter, ONO-4819 (10 μg/kg) was injected into intact rats twice a day for 5 weeks, and their bones were then analyzed by morphological techniques. The effects of ONO-4819 on the differentiation of bone cells were also examined in vitro. Bone morphometric analysis showed that osteoblast number, bone volume, mineral apposition rate, and bone formation rate were significantly increased by ONO-4819, whereas osteoclast number was not affected. Immunohistochemical examination demonstrated that ONO-4819 increased the number of Runx2- and Osterix-positive osteoblasts in rats. In vitro studies using the multipotent mesenchymal cell line C3H10T1/2 showed that ONO-4819 induced alkaline phosphatase (ALPase) activity and up-regulated the mRNA expression of ALPase and Osterix. In contrast, ONO-4819 reduced the mRNA expression of peroxisome proliferator-activated receptor γ (PPARγ) and inhibited adipocyte differentiation of C3H10T1/2 cells, which findings are consistent with the observation that the age-dependent increase in adipocyte number in the bone marrow was significantly suppressed in the ONO-4819-treated animals. ONO-4819 also dose-dependently increased osteoclast-like cell formation in vitro, but the required concentrations were much higher than those to induce osteoblast differentiation. These results collectively suggest that ONO-4819 increased bone formation by stimulating osteoblast differentiation and function, possibly through modulating mesenchymal cell differentiation in the bone.     

Prospective comparison of transcatheter arterial chemoembolization with Lipiodol-epirubicin and Lipiodol-cisplatin for treatment of recurrent hepatocellular carcinoma

Purpose

The aim of this study was to compare the safety and short-term efficacy of transcatheter arterial chemoembolization (TACE) using cisplatin-Lipiodol suspension (CP/Lp) with that using epirubicin-Lipiodol emulsion (EP/Lp) in patients with recurrent hepatocellular carcinoma (HCC).

Materials and methods

A total of 28 HCC patients were enrolled prospectively and assigned to the CP/Lp group or EP/Lp group. Adverse effects related to TACE were graded; and the treatment effect (TE) on HCC nodules at 3 months and overall tumor response at 6 months were assessed as the endpoint.

Results

No significant difference was observed between the groups regarding the frequency of adverse effects of grade 3 or less. The TE rates for 100% necrosis plus >50% necrosis in 62 HCC nodules in the CP/Lp group and 75 HCC nodules in the EP/Lp group were 72.6% and 66.7%, respectively (P = 0.894). Overall tumor response revealed that six patients (50.0%) in the CP/Lp group and six patients (37.5%) in the EP/Lp group had a partial response plus a complete response, with no significant difference (P = 0.615). TACE-free control curves for both groups revealed no significant difference (P = 0.513).

Conclusion

No significant difference was found with regard to adverse effects, the treatment effect on HCC nodules, or overall tumor response between the CP/Lp and EP/Lp groups.