The clinical significance of L-type amino acid transporter 1 (LAT1) expression remains unclear, whereas many experimental studies have demonstrated that LAT1 is associated with the proliferation of ...cancer cells. The purpose of this study was to evaluate the prognostic value of LAT1 in patients with nonsmall cell lung cancer (NSCLC). A total of 321 consecutive patients with completely resected pathologic stage I-III NSCLC were retrospectively reviewed. Expression of LAT1 and proliferative activity, as determined by the Ki-67 labelling index, was also evaluated immunohistochemically and correlated with the prognosis of patients who underwent complete resection of the tumour. Expression of LAT1 was positive in 163 patients (51%) (29% of adenocaricnoma (58 of 200 patients), 91% of squamous cell carcinoma (91 of 100 patients), and 67% of large cell carcinoma (14 of 21 patients)). The 5-year survival rate of LAT1-positive patients (51.8%) was significantly worse than that of LAT1-negative patients (87.8%; P<0.001). L-type amino acid transporter 1 expression was significantly associated with lymph node metastasis and disease stage. Multivariate analysis confirmed that positive expression of LAT1 was an independent factor for predicting a poor prognosis. There was a significant correlation between LAT1 expression and Ki-67 labelling index. LAT1 expression is a promising pathological factor to predict the prognosis in patients with resectable stage I-III NSCLC.
Here, we report a novel target of the drug memantine, ATP-sensitive K
(K
) channels, potentially relevant to memory improvement. We confirmed that memantine antagonizes memory impairment in ...Alzheimer's model APP23 mice. Memantine increased CaMKII activity in the APP23 mouse hippocampus, and memantine-induced enhancement of hippocampal long-term potentiation (LTP) and CaMKII activity was totally abolished by treatment with pinacidil, a specific opener of K
channels. Memantine also inhibited Kir6.1 and Kir6.2 K
channels and elevated intracellular Ca
concentrations in neuro2A cells overexpressing Kir6.1 or Kir6.2. Kir6.2 was preferentially expressed at postsynaptic regions of hippocampal neurons, whereas Kir6.1 was predominant in dendrites and cell bodies of pyramidal neurons. Finally, we confirmed that Kir6.2 mutant mice exhibit severe memory deficits and impaired hippocampal LTP, impairments that cannot be rescued by memantine administration. Altogether, our studies show that memantine modulates Kir6.2 activity, and that the Kir6.2 channel is a novel target for therapeutics to improve memory impairment in Alzheimer disease patients.
The impact of acute antibody‐mediated rejection (AAMR) on the long‐term outcome on ABO‐incompatible (ABOI) kidney transplantation is not well understood. We retrospectively analyzed the long‐term ...impact of AAMR and risk factors for AAMR in 57 consecutive recipients performed between 1999 and 2004. Nineteen patients (33%) who developed AAMR within 3 months posttransplantation constituted of the AMR group. The graft survival rate was significantly lower in the AMR group (AMR vs. non‐AMR, respectively; 5 years: 84% vs. 95%; 8 years: 45% vs. 95%; p = 0.009). The prevalence of transplant glomerulopathy at 1 year posttransplantation was significantly higher in the AMR group (AMR 64% vs. non‐AMR 3%, p < 0.001). Multivariate analysis demonstrated that anti‐blood group IgG antibody titers of 1:32 at the time of transplantation (OR, 9.52; p = 0.041) and donor‐specific anti‐HLA antibodies (DSHA) detected by Luminex single bead method (OR, 5.68; p = 0.015) were independent risk factors for AAMR regardless of baseline anti‐blood group IgG antibody titers. Our results indicate that AAMR has a heavy impact on the long‐term outcome and preoperative DSHA appears to have a more significant association with poor graft outcomes than anti‐blood group antibodies, even in ABOI kidney transplantation.
In ABO‐incompatible kidney transplantation, acute antibody‐mediated rejection is associated with long‐term graft deterioration, but anti‐HLA antibodies may play a larger role than anti‐ABO blood group antibodies.
Previous reports have shown that the paracrine system may be an important mediator in bone-marrow-derived mesenchymal stem cell (MSC) therapy for ischemic diseases. Hyperglycemia and hypoxia have ...been associated with increased levels of reactive oxygen species; oxidative stress may therefore influence the paracrine effects of MSCs under hypoxic conditions in diabetic patients, although the mechanism underlying this effect remains unknown. Hypoxia-inducible factor 1α (HIF-1α) regulates the transcription of hypoxia-inducible genes. We determined the effect of high-glucose concentrations on the production of angiogenic growth factors via HIF-1α induction in hypoxic MSCs. MSCs were cultured with different glucose concentration (5.6, 11, 20, or 30 mM) for 24 h. The cells were then incubated in a hypoxic chamber (5% O₂) or under normoxia (21% O₂) for 6 or 24 h. Protein levels of HIF-1α, vascular endothelial growth factor A₁₆₅ (VEGF-A₁₆₅), and platelet-derived growth factor B (PDGF-B) were attenuated by glucose in hypoxic MSCs in a dose-dependent manner. Treatment with MG132, a specific inhibitor of proteasome activity, significantly reversed the inhibitory effect of high-glucose concentrations in hypoxic MSCs. 4-Hydroxyl-tetramethylpiperidin-oxyl (a cell-permeable superoxide scavenger) or Apocynin (a NADPH oxidase inhibitor) significantly reversed glucose-induced attenuation of VEGF-A₁₆₅, PDGF-B, and HIF-1α protein levels. Stimulation with a high-glucose concentration (30 mM) significantly increased intracellular superoxide levels in hypoxic MSCs. Our results suggest that in hypoxic MSCs the increase in intracellular superoxide levels induced by high-glucose concentrations may attenuate hypoxia-induced HIF-1α expression, which in turn attenuates hypoxia-induced VEGF-A₁₆₅ and PDGF-B transcription.
KRAS mutations are one of the most common driver mutations in non-small-cell lung cancer (NSCLC) and finding druggable target molecules to inhibit oncogenic KRAS signaling is a significant challenge ...in NSCLC therapy. We recently identified epiregulin (EREG) as one of several putative transcriptional targets of oncogenic KRAS signaling in both KRAS-mutant NSCLC cells and immortalized bronchial epithelial cells expressing ectopic mutant KRAS. In the current study, we found that EREG is overexpressed in NSCLCs harboring KRAS, BRAF or EGFR mutations compared with NSCLCs with wild-type KRAS/BRAF/EGFR. Small interfering RNAs (siRNAs) targeting mutant KRAS, but not an siRNA targeting wild-type KRAS, significantly reduced EREG expression in KRAS-mutant and EREG-overexpressing NSCLC cell lines. In these cell lines, EREG expression was downregulated by MEK and ERK inhibitors. Importantly, EREG expression significantly correlated with KRAS expression or KRAS copy number in KRAS-mutant NSCLC cell lines. Further expression analysis using 89 NSCLC specimens showed that EREG was predominantly expressed in NSCLCs with pleural involvement, lymphatic permeation or vascular invasion and in KRAS-mutant adenocarcinomas. In addition, multivariate analysis revealed that EREG expression is an independent prognostic marker and EREG overexpression in combination with KRAS mutations was associated with an unfavorable prognosis for lung adenocarcinoma patients. In KRAS-mutant and EREG overexpressing NSCLC cells, siRNA-mediated EREG silencing inhibited anchorage-dependent and -independent growth and induced apoptosis. Our findings suggest that oncogenic KRAS-induced EREG overexpression contributes to an aggressive phenotype and could be a promising therapeutic target in oncogenic KRAS-driven NSCLC.
Cyanobacteria have several putative photoreceptors (designated cyanobacteriochromes) that are related to but distinct from the established phytochromes. The GAF domain of the phototaxis regulator, ...PixJ, from a thermophilic cyanobacterium Thermosynechococcus elongatus BP-1 (TePixJ_GAF) is a cyanobacteriochrome which exhibits reversible photoconversion between a blue light-absorbing form (max = 433 nm) and a green light-absorbing form (max = 531 nm). To study the chromophore, we prepared TePixJ_GAF chromoprotein from heterologously expressed Synechocystis and performed spectral analysis after denaturation by comparing it with the cyanobacterial phytochrome Cph1 which harbors phycocyanobilin (PCB) as a chromophore. The results indicated that the chromophore of TePixJ is not PCB, but its isomer, phycoviolobilin (PVB). It is suggested that the GAF domain of TePixJ has auto-lyase and auto-isomerase activities.
The molecular mechanisms that regulate the proliferation and differentiation of induced pluripotent stem (iPS) cells are of great interest. However, whether stimulation with nicotine enhances the ...proliferation and differentiation of iPS cells has not been investigated. In the present study, western blot analysis revealed that the α4-nAchR and α7-nAchR are expressed in mouse iPS cells. Mouse iPS cells were treated with nicotine for 24 h under feeder-free conditions. Mouse iPS cells were guided to differentiate into mesodermal progenitor cells on type IV collagen (Col IV)-coated dishes in differentiation medium. Mouse iPS cells were guided to differentiate into neural progenitor cells by embryoid body (EB) formation on ultra-low-attachment dishes. After 4 days of growth, all-trans retinoic acid (ATRA; 1 μM) or nicotine (300 nM) was added to the EB cultures and maintained for additional 4 days and plated onto fibronectincoated plates. A BrdU incorporation assay showed that treatment with 300 nM nicotine significantly increased the DNA synthesis of mouse iPS cells or mouse iPS cell-derived mesodermal progenitor cells. This effect was significantly inhibited by pretreatment with an α4-nAchR antagonist, an α7-nAchR antagonist, or a CaMKII inhibitor. The differentiation potential of mouse iPS cells into mesodermal progenitor cells or neural progenitor cells was not affected by the nicotine treatment. The present study indicates that stimulation of the α4-nAchR and α7-nAchR may lead to a significant increase in the proliferation of mouse iPS cells or mouse iPS cell-derived mesodermal progenitor cells through the CaMKII signaling pathway.
In order to accurately predict the vibration characteristics of structure-borne sound transmission in buildings, wave-based numerical methods are effective from the viewpoint of the modeling accuracy ...of the physical mechanism and the detailed geometries of the simulated field. However, because of the performance of current PCs, the prediction of real-scale problems remains difficult. In order to address such problems, we herein propose a vibration simulation method for a beam-plate structure using a dimension-reduced modeling method. The target structure is modeled as a composite structure consisting of two-dimensional plate elements and one-dimensional beam elements, which are coupled based on the implicit finite-difference approximation scheme. By applying such a low-dimensional element, a faster simulation that requires less memory, as compared with a three-dimensional discretization scheme, is made available. Good agreement between the measured and simulated results for the vibration characteristics of acrylic beam-plate models indicates the validity of the proposed method.
Background It has been reported that the prevalence of gastroesophageal reflux (GER) disease is high in patients with obstructive sleep apnea (OSA). End‐inspiratory intra‐esophageal pressure ...decreases progressively during OSA, which has been thought to facilitate GER in OSA patients. The aim of our study was to clarify the mechanisms of GER during sleep (sleep‐GER) in OSA patients.
Methods Eight OSA patients with reflux esophagitis (RE), nine OSA patients without RE, and eight healthy controls were studied. Polysomnography with concurrent esophageal manometry and pH recording were performed.
Key Results Significantly more sleep‐GER occurred in OSA patients with RE than without RE or in controls (P < 0.05). The severity of OSA did not differ between OSA patients with RE and without RE. Sleep‐GER was mainly caused by transient lower esophageal sphincter relaxation (TLESR), but not by negative intra‐esophageal pressure during OSA. During OSA gastroesophageal junction pressure progressively increased synchronous to intra‐esophageal pressure decrease. OSA patients had significantly more TLESR events during sleep related to preceding arousals and shallow sleep, but the number of TLESR events was not related to RE.
Conclusions & Inferences In OSA patients, sleep‐GER was mainly caused by TLESR, but not by negative intra‐esophageal pressure due to OSA.
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