Atrial Fibrillation-triggered Ventricular Fibrillation in a Patient with Early Repolarization Syndrome

A 54-year-old man with early repolarization syndrome (ERS) implanted with an implantable cardioverter-defibrillator (ICD) developed persistent atrial fibrillation (AF) three years after the implantation. Similarly, the remote monitoring system begun frequently detecting ventricular fibrillation (VF) and polymorphic ventricular tachycardia (PVT). Longer RR intervals were repeatedly observed just before the initiation of PVT/VF. Catheter ablation for AF successfully diminished both the PVT and VF events.     

Baicalin induces apoptosis via mitochondrial pathway as prooxidant

Baicalin is a flavonoid and a major component of a herbal medicine, Sho-saiko-to, which is commonly used for treatment of chronic hepatitis in Japan and China. Flavonoids including baicalin have been reported to not only function as anti-oxidants but also cause cytotoxic effect. We investigated the mechanism of baicalin-induced cytotoxicity in leukemia-derived T cell line, Jurkat cells. When cells were cultured with 50-200 microg/ml baicalin for 6h, caspase-3 was activated and then cells fell into apoptosis. Induction of apoptosis by baicalin was accompanied with the marginal generation of intracellular reactive oxygen species (ROS), the increase of the cytosolic fractions of cytochrome c, and the disruption of mitochondrial transmembrane potential (DeltaPsi(m)) prior to the activation of caspase-3. The pre-culture with 5 mM of buthionine sulfoximine (BSO), an inhibitor of glutathione (GSH) synthesis, facilitated baicalin-induced disruption of DeltaPsi(m) and induction of apoptosis. The pre-culture with N-benzyloxycarbonyl-valyl-alanyl-aspartyl fluoromethylketone (Z-VAD-fmk), a pan-caspase inhibitor, partially suppressed the induction of apoptosis. On the other hand, baicalin showed little toxic effect on peripheral blood mononuclear cells (PBMCs) from healthy volunteers. These results indicate that baicalin acts as a prooxidant and induces caspase-3 activation and apoptosis via mitochondrial pathway.     

Analysis of serum ErbB-2 protein and HLA-DRB1 in Japanese patients with lung cancer

We investigated the relationship between ErbB-2 and HLA in order to clarify the clinical and genetic factors related to Japanese patients with lung cancer. Thirty-nine of the 73 lung cancer patients (53.4%) had elevated levels of ErbB-2. Only seven of 23 (30. 4%) patients with small cell carcinoma had elevated ErbB-2 levels. The prevalence of ErbB-2 positivity was highest (23 of 32; 71.8%) in patients with adenocarcinoma, while that in patients with squamous cell carcinoma was 50% (9 of 18). The frequencies of HLA A33, B44, B62, and B75 were lower in the lung cancer patients than in the control group. HLA-DR9 was higher in frequency in lung cancer patients than in the healthy controls (P<0.05), but HLA-DR6 was lower in frequency in lung cancer patients than in controls (P<0.01). DRB1*0901 was significantly higher in frequency in lung cancer patients than in controls (P<0.05). On the other hand, DRB1*0802, DRB1*1302 and the DRB1*14 group (*1401, *1403, *1405, *1406, and *1407) were completely absent in lung cancer patients. The frequencies of HLA B35, B52, B62, DRB1*0404, and DRB1*0406 were higher in the ErbB-2-positive lung cancer patients than in the ErbB-2-negative lung cancer patients. However, these types of HLA were not included in significant frequencies in our group of lung cancers. Our results suggest that some HLA-antigens/alleles participate in the pathogenesis of lung cancer in Japanese patients. In addition, the relationship between HLA-associated genetic factors and ErbB-2 seems to be weak. These findings suggest that ErbB-2 is correlated with prognostic factors for lung cancer independently of HLA-associated genetic factors.     

Identification of a trypsinogen activity stimulating factor produced by pancreatic cancer cells: its role in tumor invasion and metastasis

Trypsinogen/trypsin is one of the major serine proteases and is produced by pancreatic acinar cells. Tumor-associated trypsinogen (TAT) has been reported to be produced by several cancer cell lines. The biological roles and activation mechanisms of both TAT and pancreatic acinar trypsinogen (PAT) have not been elucidated in the context of cancer extension, in particular at the stage of invasion and metastasis. In this study, we investigate the roles played by PAT and TAT in pancreatic cancer invasion. In addition, we determined their mechanisms of activation and identified a trypsinogen activity-stimulating factor (TASF) produced by pancreatic cancer cells. TAT expression and high TAT activity were associated with high invasive and liver metastatic potential in SW1990 and CAPAN-2 cells. Moreover, a trypsinogen activating effect and activity prolonging effect was observed in a mixture of these supernatants with trypsinogen. These cells revealed significantly enhanced invasiveness upon invasion assay and in the presence of PAT. TAT and PAT were activated by TASF, active u-PA, produced by pancreatic cancer cells. Activated TAT and PAT can degrade not only ECM proteins but they can also activate other latent proteases. This ECM-protease-network may form a vicious cycle, thereby promoting tumor cell invasion.     

Quantitative elemental analysis on aluminum accumulation by HVTEM-EDX in liver tissues of mice orally administered with aluminum chloride

Quantitative elemental analysis on Al was carried out by high-accelerating voltage transmission electron microscopy (HVTEM) equipped with energy-dispersive X-ray microanalysis (EDX) using an accelerating voltage at 300 kV with high permeability in 1-μm-thick samples obtained from mice administered with aluminum chloride solution for 3, 9, and 17 weeks. By light microscopic observation, no morphological changes were observed in the hepatocytes and macrophages in the liver tissues of mice that were administered with excess Al as compared with the normal control mice. In contrast, by electron microscopic observation, ultrastructural changes were observed in the lysosomes in the hepatocytes as well as the pinocytotic vesicles in the macrophages in the experimental animals. Therefore, the concentrations of Al detected in lysosomes in hepatocytes and pinocytotic vesicles in macrophages of livers of mice administered with Al were measured in relationship to those administration periods. Moreover, transitional changes of hepatocyte lysosome ratios by image analysis and the macrophage counts in the unit area increased in liver tissues of mice administered with Al as compared with normal control mice. From the results, it was demonstrated that hepatocyte lysosome ratio and macrophage count increased in liver tissues of treated mice during those short-term excessive Al administration periods. It was also clarified that the concentrations of Al in both hepatocytes and macrophages increased as observed by HVTEM-EDX. In conclusion, Al accumulated in hepatocytes and macrophages at 3 and 9 weeks administration, while the ultrastructural changes remained in the hepatocytes and macrophages. In contrast, Al concentration did not increase in the liver at 17 weeks administration.     

Activation of insular cortex and subcortical regions related to feedback stimuli in a time estimation task: an fMRI study

We used functional magnetic resonance imaging to investigate brain activity related to motivational function of informative feedback stimuli in a time estimation task. In that task, subjects pressed a button as a response 3 s after a cue stimulus; a visual feedback stimulus was presented 2 s after the response. In a true feedback condition, subjects received true information (informative feedback) about their time-estimation performance. In the false feedback condition, the same visual signs were used, but they were presented randomly. Therefore, they were not related to actual performance. In the 20 subjects examined, higher hemodynamic responses were identified in the insular cortex, the thalamus, and the striatum by comparing the true feedback condition to the false feedback condition. The time estimation performance and subjective score on motivation were also markedly higher in the true feedback condition. The anterior insular cortex and striatal regions are known to be involved in motivational and reward processing. Therefore, the hemodynamic responses observed in this study suggest that the motivational function of the feedback information is a crucial factor for behavioral learning; it is considered that the informative feedback might serve as an implicit reward for humans.     

Tuning of Sol–Gel Transition in the Mixed Polymer Micelle Solutions of Copolymer Mixtures Consisting of Enantiomeric Diblock and Triblock Copolymers of Polylactide and Poly(ethylene glycol)

Poly(ethylene glycol) (PEG) is partially furanylated with different feed ratios of furfuryl isocyanate and used as the macro initiator of ring‐opening polymerization of l ‐ and d ‐lactides to synthesize copolymer mixtures of furan‐terminated AB diblock and ABA triblock copolymers (poly(oxyethylene)–poly(l ‐lactide)/poly(l ‐lactide)–poly(oxyethylene)–poly(l ‐lactide) and poly(oxyethylene–poly(d ‐lactide)/poly(d ‐lactide)–poly(oxyethylene)–poly‐(d ‐lactide)) having different diblock/triblock ratios. The mixed micelle solutions of these enantiomeric copolymer mixtures undergo sol‐to‐gel or gel‐to‐sol transition depending on the diblock/triblock ratio of the copolymer mixtures. The rheological properties of the mixed micelle solutions could also be controlled by changing the diblock/triblock ratios or the initial furanylation ratio of PEG.

     

Maternal administration of bisphenol A alters the microglial profile in the neocortex of mouse weanlings

Bisphenol A (BPA) is known to cause abnormal neurogenesis in the developing neocortex. The mechanisms of BPA toxicity concerning neuroinflammatory-related endpoints are incompletely characterized. To evaluate the microglial morphology and the gene expression of pro-inflammatory cytokines in the newborn neocortex, ICR mice were exposed to BPA 200 μg/kg/d on gestational day 6 through post-partum day 21. Weanlings exposed during prenatal and postnatal period to BPA showed an increased number of amoeboid-type microglia, a microglial differentiation disruption (the M1/M2 microglial ratio), and an abnormal expression of genes encoding pro-inflammatory factors. These findings suggest that the well-known neurodevelopmental toxicity of BPA may be related to an increased microglial activation and neuroinflammation in the neocortex.