Role of squalene synthase in prostate cancer risk and the biological aggressiveness of human prostate cancer

BACKGROUND

We previously conducted a genome-wide linkage analysis of Japanese nuclear families affected with prostate cancer and showed that the susceptibility to prostate cancer was closely linked to D8S550 at 8p23. The role of farnesyl diphosphate farnesyltransferase (FDFT1), which is located under the peak marker D8S550 at 8p23, and squalene synthase, the enzyme encoded by FDFT1, in prostate cancer was studied.

METHODS

The association among common variants of FDFT1 with prostate cancer risk, the promoter activities of FDFT1 with different genotypes and the effects of inhibition of squalene synthase were studied, and the FDFT1 transcript levels of human prostate samples were quantified.

RESULTS

The A allele of rs2645429 was significantly associated with prostate cancer risk in a Japanese familial prostate cancer population. Rs2645429 was located in the promoter region of FDFT1, and the AA genotype showed significantly increased promoter activity. The knockdown of FDFT1 mRNA expression or squalene synthase inhibition led to a significant decrease in prostate cancer cell proliferation. Additionally, human prostate cancer specimens expressed significantly higher levels of FDFT1 mRNA compared with noncancerous specimens. Finally, aggressive cancers showed higher transcript levels.

CONCLUSIONS

FDFT1 and its encoded enzyme, squalene synthase, may play an important role in prostate cancer development and its aggressive phenotypes.

Enhanced bile canaliculi formation enabling direct recovery of biliary metabolites of hepatocytes in 3D collagen gel microcavities

Analysis of biliary metabolites is essential to predict pharmacokinetics and hepatotoxicity during drug development. In this paper, we present a hepatocyte culture configuration that enables the direct recovery of bile acid that accumulates in bile canaliculi by embedding the hepatocytes in a 3D micropatterned collagen gel substrate. We investigated the formation of bile canaliculi in hepatocytes embedded in circular microcavities of various sizes and made from collagen gel. Image analyses using fluorescently labeled bile acid revealed that the area of bile canaliculi in embedded hepatocytes in a microcavity of 60 or 80 μm in diameter was enlarged when compared with other sized microcavities and those of hepatocytes cultured using conventional hepatocyte sandwich cultures. We successfully recovered bile acid from the enlarged bile canaliculi of hepatocytes cultured in microcavities using a glass capillary and quantified the amount recovered. Using our approach, the direct recovery of biliary metabolites, using hepatocyte cultures with enhanced biliary excretion and geometrically enlarged bile canaliculi, may enable accurate screening of pharmacokinetics and drug-drug interactions against drug transporters.

Rebamipide attenuates nonsteroidal anti-inflammatory drugs (NSAID) induced lipid peroxidation by the manganese superoxide dismutase (MnSOD) overexpression in gastrointestinal epithelial cells

Nonsteroidal anti-inflammatory drugs (NSAIDs) often cause gastrointestinal complications such as gastric ulcers and erosions. Recent studies on the pathogenesis have revealed that NSAIDs induce lipid peroxidation in gastric epithelial cells by generating superoxide anion in mitochondria, independently with cyclooxygenase-inhibition and the subsequent prostaglandin deficiency. Although not clearly elucidated, the impairment of mitochondrial oxidative phosphorylation, or uncoupling, by NSAIDs is associated with the generation of superoxide anion. Physiologically, superoxide is immediately transformed into hydrogen peroxide and diatomic oxygen with manganese superoxide dismutase (MnSOD). Rebamipide is an antiulcer agent that showed protective effects against NSAID-induced lipid peroxidation in gastrointestinal tracts. We hypothesized that rebamipide may attenuate lipid peroxidation by increasing the expression of MnSOD protein in mitochondria and decreasing the leakage of superoxide anion in NSAID-treated gastric and small intestinal epithelial cells. Firstly, to examine rebamipide increases the expression of MnSOD proteins in mitochondria of gastrointestinal epithelial cells, we underwent Western blotting analysis against anti-MnSOD antibody in gastric RGM1 cells and small intestinal IEC6 cells. Secondly, to examine whether the pretreatment of rebamipide decreases NSAID-induced mitochondrial impairment and lipid peroxidation, we treated these cells with NSAIDs with or without rebamipide pretreatment, and examined with specific fluorescent indicators. Finally, to examine whether pretreatment of rebamipide attenuates NSAID-induced superoxide anion leakage from mitochondria, we examined the mitochondria from indomethacin-treated RGM1 cells with electron spin resonance (ESR) spectroscopy using a specific spin-trapping reagent, CYPMPO. Rebamipide increased the expression of MnSOD protein, and attenuated NSAID-induced mitochondrial impairment and lipid peroxidation in RGM1 and IEC6 cells. The pretreatment of rebamipide significantly decreased the signal intensity of superoxide anion from the mitochondria. We conclude that rebamipide attenuates lipid peroxidation by increasing the expression of MnSOD protein and decreasing superoxide anion leakage from mitochondria in both gastric and small intestinal epithelial cells.

Development of a highly efficient implanted thermal ablation device: in vivo experiment in rat liver

OBJECTIVES

To evaluate an implanted thermal ablation device that can be heated with high efficiency using a resonant circuit as the implant.

METHODS

16 rats were used. The implants, adjusted at a resonance frequency of 4 MHz, were fixed on the surface of the liver of rats under laparotomy. In 14 of 16 rats, an alternating magnetic field (AMF) was applied for 6 min with an output of 300 W from outside the body using a ferrite core applicator. The implant temperature during AMF exposure was measured. The 14 rats were divided into 5 groups, depending on time from AMF application until they were sacrificed (1 h, 1 day, 3 days, 7 days and 1 month after application). Two rats not exposed to AMF were used as controls. Livers were removed and evaluated; the cross-sectional area and width of the ablated region were measured.

RESULTS

During AMF exposure, the implant temperature rose to 127.8±39.3 °C (mean±standard deviation). The cross-sectional area of the ablated region was largest after 1 day and tended to decrease with time. The widths of the ablated region were 4.87±0.22 mm, 4.15±0.36 mm, 3.67±0.58 mm and 3.24±0.16 mm in the 1 day, 3 day, 7 day and 1 month groups, respectively. No significant differences (p<0.05) were seen in either cross-sectional area or width of the ablated region.

CONCLUSION

Sufficient heat for ablation was obtained in vivo using a newly developed implanted thermal ablation device. This device may be a new option for thermal ablation therapy.

Safety, pharmacokinetics and resistant variants of telaprevir alone for 12 weeks in hepatitis C virus genotype 1b infection

BACKGROUND

Telaprevir in combination with peginterferon and ribavirin is a promising advancement in chronic hepatitis C treatment. However, the safety, tolerability, pharmacokinetics and antiviral profiles of telaprevir alone beyond 2 weeks have not been studied.

METHODS

In a phase 1b study in Japan, 10 treatment-naïve patients infected with hepatitis C virus genotype 1b with high viral load (>5 log(10) IU/mL) received telaprevir 750 mg every 8 h (q8h) for 12 weeks. We examined the safety, tolerability, pharmacokinetics, hepatitis C virus (HCV) RNA levels and resistant variants of telaprevir.

RESULTS

Neither serious adverse events nor discontinuations of study drug owing to an adverse event occurred. The most common adverse drug reactions were rash (80%) and anaemia (70%). Telaprevir concentration reached its steady state within 2 days after the first administration without abnormal accumulation. Telaprevir alone provided potent antiviral activity: a median log(10) decrease of 2.325 at 16 h and 5.175 on Day 14. During the treatment, HCV RNA levels at the nadir were below the limit of the quantification in seven patients and undetectable in three of 10 patients. Viral breakthrough associated with mainly Ala(156) -substituted variants occurred in eight patients, and only one patient showed end-of-treatment response. The selected variants reverted to the wild-type during the 24-week follow-up period.

CONCLUSION

Telaprevir alone was well tolerated at 750 mg q8h for up to 12 weeks. The safety profile and emergence of resistant variants of genotype 1b under telaprevir monotherapy for 12 weeks will become increasingly important in evaluating an oral combination of telaprevir with other direct-acting antiviral agents.

Comparison of ex-vivo high-resolution episcopic microscopy with in-vivo four-dimensional high-resolution transvaginal sonography of the first-trimester fetal heart

OBJECTIVE

To compare the capability of three-dimensional (3D) reconstructed images produced by high-resolution episcopic microscopy (HREM) with that of in-vivo four-dimensional high-resolution transvaginal sonography (4D-HRTVS) to discern morphological features of the first-trimester human fetal heart.

METHODS

This was a prospective study of fetal hearts between 9 and 14 weeks' gestation. For ex-vivo 3D analysis, 30 human fetal hearts (at 9 + 0 to 14 + 6 weeks) were retrieved from surgical terminations of pregnancy. The specimens were embedded in resin and episcopic ('block-face') imaging was used to obtain a digital volume dataset (HREM) using 3-micron slicing. 4D-HRTVS was performed in 28 separate pregnancies at 10 + 2 to 14 + 0 weeks using a Voluson E8 ultrasound machine with volumetric transvaginal RIC 6-12-MHz transducers. Heart volumes obtained by both methods were compared to assess their ability to demonstrate first-trimester cardiac morphology. Comparisons were made in the transverse and sagittal planes, and using volume rendering.

RESULTS

All hearts were structurally normal, although abdominal situs was not examined in the isolated hearts that underwent HREM. 4D-HRTVS demonstrated each of the complete five transverse cardiac views in 32-86% of cases. HREM showed four features unique to the first-trimester human heart: prominent atrial appendages, spiral ventricular arrangement, prominent coronary arteries and thickened arterial walls. 4D-HRTVS could demonstrate the first two, but ultrasound resolution was too poor to quantify wall thickness and demonstrate coronary arteries in the 3-5-mm diameter heart.

CONCLUSIONS

4D-HRTVS showed limited morphological features of the first-trimester fetal heart compared with HREM. HREM provides a gold standard of ex-vivo imaging against which developments in ultrasound resolution could be compared.

Neonatal Fc receptor for IgG (FcRn) expressed in the gastric epithelium regulates bacterial infection in mice

Neonatal Fc receptors for immunoglobulin (Ig)G (FcRn) assume a central role in regulating host IgG levels and IgG transport across polarized epithelial barriers. We have attempted to elucidate the contribution of FcRn in controlling Helicobacter infection in the stomach. C57BL/6J wild-type or FcRn(-/-) mice were infected with Helicobacter heilmannii, and gastric lesions, bacterial load and the levels of antigen-specific IgG in serum and gastric juice were analyzed. The elevated levels of anti-H. heimannii IgG in gastric juice were observed exclusively in wild-type mice but not in FcRn(-/-) mice. In contrast, an increase in lymphoid follicles and bacterial loads along with deeper gastric epithelium invasion were noted in FcRn(-/-) mice. C57BL/6J wild-type or FcRn(-/-) mice were also infected with Helicobacter pylori SS1, and the results of the bacterial load in stomachs of these mice and the anti-H. pylori IgG levels in serum and gastric juice were similar to those from H. heilmannii infection. Our data suggest that FcRn can be functionally expressed in the stomach, which is involved in transcytosis of IgG, and prevent colonization by H. heilmannii and the associated pathological consequences of infection.

Antidepressant-like effect of sildenafil through oxytocin-dependent cyclic AMP response element-binding protein phosphorylation

Oxytocin (OT) levels in plasma increase during sexual response and are significantly lower in patients with depression. A drug for the treatment of sexual dysfunction, sildenafil, enhances the electrically evoked release of OT from the posterior pituitary. In this study, we showed that sildenafil had an antidepressant-like effect through activation of an OT signaling pathway. Application of sildenafil reduced depression-related behavior in male mice. The antidepressant-like effect was blocked by an OT receptor (OTR) antagonist and was absent in OTR knockout (KO) mice. Sildenafil increased the phosphorylation of cAMP response element-binding protein (CREB) in the hippocampus. The OTR antagonist inhibited sildenafil-induced CREB phosphorylation and sildenafil had no effect on CREB phosphorylation in OTR KO mice. These results suggest sildenafil to have an antidepressant-like effect through the activation of OT signaling and to be a promising drug for the treatment of depression.

Optical dynamics of energy-transfer from a CdZnO quantum well to a proximal Ag nanostructure

We studied photoluminescence (PL) and energy-transfer dynamics in a hybrid structure comprising a Cd(0.08)Zn(0.92)O quantum well (QW) and an Ag nanostructure. The observed PL quenching was dependent on the electronic states in the QW. Quenching occurred at low temperature where excited carriers recombined radiatively because of excitonic localization, which disappeared with increasing temperature due to delocalization of excitons. Furthermore, nanostructured Ag surfaces produced local surface plasmon (LSP) absorption that was resonant with the PL peak energy of the QW emission. These results indicate that the recombination energy of excitons transfers nonradiatively to induce LSP excitation, which was revealed using time-resolved PL measurements.

Endoscopy-assisted anastomosis: a modified technique for laparoscopic side-to-side esophagojejunostomy following a total gastrectomy

INTRODUCTION

Esophagojejunostomy with a circular stapling device is sometimes difficult to perform in a laparoscopic setting. On the other hand, a side-to-side anastomosis with a linear stapling device is technically challenging.

METHODS

Between June 2002 and March 2008, 10 consecutive patients underwent a laparoscopy-assisted total gastrectomy using a side-to-side anastomosis technique. Of these patients, four underwent a laparoscopy-assisted total gastrectomy with a modified anastomosis technique. A small wound was created on the antimesenteric side of the jejunum 5 cm distal to the resected portion and then in the lower esophagus. A peroral endoscope was advanced to the hole, and the cartridge fork was introduced into the lower esophagus under endoscopic guidance. The device (45 mm, blue) was fired to create an antiperistaltic side-to-side anastomosis. The common entry hole was closed by transecting the jejunum and the esophagus with another linear stapler and by using an endoscope as a stent.

RESULTS

Four patients underwent the modified procedure and did not require an open procedure. One patient developed a pancreatic fistula, which was treated conservatively. The average operative time, reconstruction time and blood loss were 483 ± 133 minutes, 139 ± 31 minutes, and 199 ± 121 mL, respectively. An introduction of the stapler into the lower esophagus and a closure of the common entry hole were performed safely without any stress.

CONCLUSION

Although several techniques must be compared to determine the ideal procedure for laparoscopic esophagojejunostomy, the modified side-to-side anastomosis technique may be useful in clinical settings.

[Evaluation of a new compact prothrombin time-international normalized ratio measurement device in pediatric management]

BACKGROUND

In a pediatric setting, the need for lifetime oral anticoagulation is increasing because of currency of extracardiac total cavo-pulmonary connection (TCPC) and pediatric valve surgery. We evaluated a new compact device "CoaguChek XS" for measuring prothrombin time-internatinal normalized ratio (PT-INR).

METHODS

The international normalized ratio (INR) values obtained from 71 patients (223 samples) by a CoaguChek XS were compared with those obtained by a laboratory-based coagulation analyzer.

RESULTS

The values from the CoaguChek XS had a significant correlation with the laboratory based results. (r2 = 0.92, p < 0.01, regression line y = 1.05 x -0.02).

CONCLUSION

The CoaguChek XS will be useful in pediatric management.

Expression of MMP-8 and MMP-13 in the development of periradicular lesions

AIM

To elucidate the expressions of MMP-8 and MMP-13 in experimentally induced rat periradicular lesions by means of the reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemical staining.

METHODOLOGY

Thirty rats were used and periradicular lesions in mandibular first molar teeth were established following pulp exposure. The animals were sacrificed at 0 (no exposure control), 1, 2, 3, 4 and 6 weeks after pulp exposure. The right molars were used for RT-PCR analysis of MMP-8 and MMP-13. The left molars were subjected to immunohistochemical staining with both MMPs. The areas of these lesions were measured histometrically, and the numbers of both reactive cells in the periapical portion were counted per unit area. Significant differences were analysed by the Mann-Whitney U-test.

RESULTS

MMP-8 gene expression gradually increased from 2 to 4 weeks, but slightly decreased at 6 weeks. MMP-13 gene expression gradually increased from 1 to 3 weeks. At 4 and 6 weeks, the level of expression was as high as that at 3 weeks. Immunohistochemically, MMP-8 was first detected at 2 weeks and gradually increased until 4 weeks. MMP-13 gradually increased from 1 to 4 weeks. Both MMPs decreased at 6 weeks. The area of the periradicular lesions gradually increased from 1 to 4 weeks, showing a large increase in week 2 and 3 in particular, but then decreased in week 6. MMP-13-expressing cells were significantly greater than MMP-8-positive cells at week 1 and 2.

CONCLUSIONS

These findings indicate that MMP-8 and MMP-13 were related to the development of periradicular lesions. It is suggested that MMP-13 increased from an early stage during their development and that MMP-8 is involved in the progression of tissue destruction including bone resorption.

Seismic Velocity Structure of the EDZ Around Drifts at the Kamaishi and Tono Mines in Japan

The excavation disturbed zone (EDZ) is defined as the rock zone where rock properties and conditions have been changed due to the processes induced by excavation, such as excavation damage, stress redistribution and desaturation. In-situ excavation disturbance experiment has been performed to determine the rock properties and width of the EDZ at the Kamaishi and Tono mines in Japan. Rock mass fails when blasting vibration velocity exceeds limit velocity so that we can estimate excavation damaged zone from vibration measurement. The width of the zone where blasting vibration velocity exceeded the limit velocity is roughly consistent with the width of low seismic velocity layer detected from the seismic refraction survey at both mines.

Temporal and spatial performance of vector velocity imaging in the human fetal heart

OBJECTIVES

To assess the spatial and temporal performance of fetal myocardial speckle tracking, using high-frame-rate (HFR) storing and Lagrangian strain analysis.

METHODS

Dummy electrocardiographic signaling permitted DICOM HFR in 124 normal fetuses and paired low-frame-rate (LFR) video storing at 25 Hz in 93 of them. Vector velocity imaging (VVI) tracking co-ordinates were used to compare time and spatial domain measures. We compared tracking success, Lagrangian strain, peak diastolic velocity and positive strain rate values in HFR vs. LFR video storing. Further comparisons within an HFR subset included Lagrangian vs. natural strain, VVI vs. M-mode annular displacement, and VVI vs. pulsed-wave tissue Doppler imaging (TDI) peak velocities.

RESULTS

HFR (average 79.4 Hz) tracking was more successful than LFR (86 vs. 76%, P = 0.024). Lagrangian and natural HFR strain correlated highly (left ventricle (LV): r = 0.883, P < 0.001; right ventricle (RV): r = 0.792, P < 0.001) but natural strain gave 20% lower values, suggesting reduced reliability of measurement. Lagrangian HFR strain was similar in LV and RV and decreased with gestation (P = 0.015 and P < 0.001, respectively). LV Lagrangian LFR strain was significantly lower than the values for the RV (P < 0.001) and those using paired LV-HFR recordings (P = 0.007). Annular displacement methods correlated highly (LV = 1.046, r = 0.90, P < 0.001; RV = 1.170, r = 0.88, P < 0.001). Early diastolic waves were visible in 95% of TDI, but in only 26% of HFR and 0% of LFR recordings, and HFR-VVI velocities were significantly lower than those for TDI (P < 0.001).

CONCLUSIONS

Doppler estimation of velocities remains superior to VVI but image gating and use of original co-ordinates should improve offline VVI assessment of fetal myocardial function.

Cytotoxicity evaluation of reactive metabolites using rat liver homogenate microsome-encapsulated alginate gel microbeads

We present an improved cytotoxicity test for reactive metabolites, in which the S9 microsomal fraction of rat liver homogenate is encapsulated in alginate gel microbeads to avoid cytotoxic effects of S9-self-generated toxicants, microsomal lipid peroxides. The S9-encapsulated gel microbeads were prepared by a coaxial two-fluid nozzle and surfaces of the microbeads were coated with poly-L-lysine (PLL). Although the initial metabolic rate of the S9-encapsulated gel microbeads was about 20% slower than that of bare S9, the microbeads prevented the leakage of microsomal lipid peroxides thanks to the dense alginate and PLL polymer networks. In fact, the half maximal effective concentration of the indirect mutagen cyclophosphamide on NIH3T3 cells in the presence of the S9-encapsulated gel microbeads was about 5 times higher than that in the presence of bare S9. Use of the S9-encapsulated gel microbeads enabled the more accurate evaluation of the cytotoxicity of the reactive metabolites without the S9-based cytotoxicity.