The Electronic State of Hydrogen in the α Phase of the Hydrogen-Storage Material PdH(D)x : Does a Chemical Bond Between Palladium and Hydrogen Exist?

The palladium-hydrogen system is one of the most famous hydrogen-storage systems. Although there has been much research on β-phase PdH(D)_x , we comprehensively investigated the nature of the interaction between Pd and H(D) in α-phase PdH(D)_x (x<0.03 at 303 K), and revealed the existence of Pd-H(D) chemical bond for the first time, by various in situ experimental techniques and first-principles theoretical calculations. The lattice expansion, magnetic susceptibility, and electrical resistivity all provide evidence. In situ solid-state ¹ H and ² H NMR spectroscopy and first-principles theoretical calculations revealed that a Pd-H(D) chemical bond exists in the α phase, but the bonding character of the Pd-H(D) bond in the α phase is quite different from that in the β phase; the nature of the Pd-H(D) bond in the α phase is a localized covalent bond whereas that in the β phase is a metallic bond.

Minimally invasive esophagectomy may contribute to long-term respiratory function after esophagectomy for esophageal cancer

Evidence suggests that minimally invasive esophagectomy has several advantages with regard to short-term outcomes, compared to open esophagectomy in esophageal cancer patients. However, the impact of minimally invasive esophagectomy on long-term respiratory function remains unknown. The objective of this study is to assess the association between use of the minimally invasive esophagectomy and long-term respiratory dysfunction in esophageal cancer patients after esophagectomy. This retrospective single institution study using prospectively collected data included 87 consecutive esophageal cancer patients who had undergone esophagectomy. All patients underwent a respiratory function test before, and one year after esophagectomy. Logistic regression analysis was used to compute the hazard ratio for long-term respiratory dysfunction. Minimally invasive esophagectomies were performed in 53 patients, and open esophagectomies in 34 patients. The two groups showed no significant differences in terms of postoperative complications and postoperative course. Nor were any differences observed between the two groups in terms of volume capacity (L) and forced expiratory volume 1.0 (L) before esophagectomy (P > 0.34). However, one year after esophagectomy, the decreases in volume capacity and forced expiratory volume 1.0 were significantly less in the minimally invasive esophagectomy group than in the open esophagectomy group (P = 0.04 and P = 0.007, respectively). Multivariate analyses revealed that minimally invasive esophagectomy was an independent favorable factor for maintenance of forced expiratory volume 1.0 (hazard ratio = 0.17, 95% confidence interval 0.04-0.71; P = 0.01). Minimally invasive esophagectomy may be an independent favorable factor for maintenance of long-term respiratory function in esophageal cancer patients after esophagectomy.

Pyloroplasty may reduce weight loss 1 year after esophagectomy

Weight loss after esophagectomy is common and is associated with unfavorable prognosis. However, the clinical features and surgical methods that influence postesophagectomy weight loss are not well characterized. This study aims to determine those features (especially the surgical methods) that may affect postoperative weight loss. We reviewed 221 esophageal cancer patients who had undergone esophagectomy at Kumamoto University Hospital (Kumamoto, Japan) between November 2012 and June 2015. Among these, we recruited 106 patients who had undergone transthoracic esophagectomy with gastric conduit reconstruction, had no cancer recurrence within 1 year, and no missing follow-up data. We tabulated the body weight changes and risk factors associated with weight loss exceeding 10% at 1-year postesophagectomy. The mean body weights at baseline and 1-year postsurgery were 60.3 kg (standard error (SE): 0.91) and 52.6 (SE: 0.91), respectively. One year postsurgery, the body weights had changed as follows: mean: -12.2%; median: -12.9%; standard deviation: 9.06; range: -36.1-18.56%; interquartile range: -10.5 to -14.0%. In the multivariate logistic regression analysis, the absence of pyloroplasty was the sole risk factor for more than 10% weight loss (OR: 3.22; 95% CI: 1.08-11.9; P = 0.036). Our data suggest that pyloroplasty with esophagectomy can overcome the post-surgical weight loss.

Theoretical study of tetrahedral site occupation by hydrogen in Pd nanoparticles

To understand the enhanced effects and new hydrogen absorption properties of metal nanoparticles, we theoretically investigated the hydrogen absorption in Pd nanoparticles, adopting the Pd₄₀₅ model of ca. 2.5 nm by using density functional theory. Pd₄₀₅ showed inhomogeneous geometric features, especially near the surface region. The hydrogen absorptions in octahedral (O) and tetrahedral (T) sites near the core region were stable and unstable, respectively, similar to the Pd bulk. We clearly demonstrated the possibility of hydrogen absorption in T sites near the surface of Pd₄₀₅. The flexible volume change and the difference in hydrogen position relative to the center of mass of the T site that we observed are important factors for stable hydrogen absorption in T sites of Pd nanoparticles. In addition, we discuss the differences in hydrogen diffusion mechanisms in the core and near surface regions, based on the stability of hydrogen absorption in O and T sites.

Monitoring sputum culture in resected esophageal cancer patients with preoperative treatment

Pneumonia is a major cause of postesophagectomy mortality and worsens the long-term survival in resected esophageal cancer patients. Moreover, preoperative treatments such as chemotherapy or chemoradiotherapy (which have recently been applied worldwide) might affect the bacterial flora of the sputum. To investigate the association among preoperative treatments, the bacterial flora of sputum, and the clinical and pathological features in resected esophageal cancer patients, this study newly investigates the effect of preoperative treatments on the bacterial flora of sputum. We investigated the association among preoperative treatments, the bacterial flora of sputum, and clinical and pathological features in 163 resected esophageal cancer patients within a single institution. Pathogenic bacteria such as Candida (14.1%), Staphylococcus aureus (6.7%), Enterobacter cloacae (6.1%), Haemophilus parainfluenzae (4.9%), Klebisiella pneumoniae (3.7%), Methicillin-resistant Staphylococcus aureus (MRSA) (3.7%), Pseudomonas aeruginosa (2.5%), Escherichia coli (1.8%), Streptococcus pneumoniae (1.8%), and Haemophilus influenzae (1.2%) were found in the sputum. The pathogen detection rate in the present study was 34.3% (56/163). In patients with preoperative chemotherapy and chemoradiotherapy, the indigenous Neisseria and Streptococcus species were significantly decreased (P= 0.04 and P= 0.04). However, the detection rates of pathogenic bacteria were not associated with preoperative treatments (all P> 0.07). There was not a significant difference of hospital stay between the sputum-monitored patients and unmonitored patients (35.5 vs. 49.9 days; P= 0.08). Patients undergoing preoperative treatments exhibited a significant decrease of indigenous bacteria, indicating that the treatment altered the bacterial flora of their sputum. This finding needs to be confirmed in large-scale independent studies or well-designed multicenter studies.

Use of PIXE/PIGE for sequential Ca and F measurements in root carious model

The progress of caries has conventionally been evaluated by checking changes in mineral density using transverse microradiography (TMR). Recent advances have seen development of a new measurement system, using in-air micro proton induced X-ray/gamma-ray emission (PIXE/PIGE). PIXE/PIGE enables analysis of distributions and concentrations of multiple mineral elements in a carious lesion. The aim of this study was to evaluate the effectiveness of PIXE/PIGE for investigating the development of root caries. In summary, we successfully established a multi-elemental sequential measuring method using in-air micro-PIXE/PIGE to identify the dynamic distributions and concentrations of Ca and F in human root dentin. The PIXE/PIGE potentially offers a useful advantageous technique for studying carious development by using as a combination with conventional techniques such as TMR and Micro-computed tomography (µCT).

Prognostic and clinical impact of sarcopenia in esophageal squamous cell carcinoma

Recently, depletion of skeletal muscle mass (sarcopenia) has been linked to poor prognosis in several types of cancers, but has not been investigated in esophageal squamous cell carcinoma (ESCC). This retrospective study investigates the relationship between sarcopenia and clinical outcome in ESCC patients treated by surgical resection or definitive chemoradiation therapy (dCRT). The study was retrospectively conducted in a single academic hospital in Kumamoto, Japan, and involved 325 ESCC patients (256 surgical cases and 69 dCRT cases) treated between April 2005 and April 2011. Skeletal muscle mass was quantified by radiologic measures using standard computed tomography scans. The skeletal muscle tissue in the 325 ESCC patients was distributed as follows: mean: 47.10; median: 46.88; standard deviation (SD): 7.39; range: 31.48-71.11; interquartile range, 46.29-47.90. Skeletal muscle tissue was greater in male patients than in female patients (P < 0.0001), but was independent of other clinical and tumor features. Sarcopenia was not significantly associated with overall survival (log rank P = 0.54). Lymph node involvement significantly altered the relationship between sarcopenia and survival rate (P for interaction = 0.026). Sarcopenia significantly reduced the overall survival of patients without lymph node involvement (log rank P = 0.035), but was uncorrelated with overall survival in patients with lymph involvement (log rank, P = 0.31). The anastomosis leakage rate was significantly higher in the sarcopenia group than in the non-sarcopenia group (P = 0.032), but other surgical complications did not significantly differ between the two groups. Sarcopenia in ESCC patients without lymph node involvement is associated with poor prognosis, indicating sarcopenia as a potential biomarker for identifying patients likely to experience an inferior outcome. Moreover, sarcopenia was associated with anastomosis leakage but no other short-term surgical outcome.

A Synthetic Pseudo-Rh: NOx Reduction Activity and Electronic Structure of Pd-Ru Solid-solution Alloy Nanoparticles

Rh is one of the most important noble metals for industrial applications. A major fraction of Rh is used as a catalyst for emission control in automotive catalytic converters because of its unparalleled activity toward NO_x reduction. However, Rh is a rare and extremely expensive element; thus, the development of Rh alternative composed of abundant elements is desirable. Pd and Ru are located at the right and left of Rh in the periodic table, respectively, nevertheless this combination of elements is immiscible in the bulk state. Here, we report a Pd–Ru solid-solution-alloy nanoparticle (Pd_xRu_1-x NP) catalyst exhibiting better NO_x reduction activity than Rh. Theoretical calculations show that the electronic structure of Pd_0.5Ru_0.5 is similar to that of Rh, indicating that Pd_0.5Ru_0.5 can be regarded as a pseudo-Rh. Pd_0.5Ru_0.5 exhibits better activity than natural Rh, which implies promising applications not only for exhaust-gas cleaning but also for various chemical reactions.

Electronic Structure and Phase Stability of PdPt Nanoparticles

To understand the origin of the physicochemical nature of bimetallic PdPt nanoparticles, we theoretically investigated the phase stability and electronic structure employing the PdPt nanoparticles models consisting of 711 atoms (ca. 3 nm). For the Pd-Pt core-shell nanoparticle, the PdPt solid-solution phase was found to be a thermodynamically stable phase in the nanoparticle as the result of difference in surface energy of Pd and Pt nanoparticles and configurational entropy effect, while it is well known that the Pd and Pt are the immiscible combination in the bulk phase. The electronic structure of nanoparticles is conducted to find that the electron transfer occurs locally within surface and subsurface layers. In addition, the electron transfer from Pd to Pt at the interfacial layers in core-shell nanoparticles is observed, which leads to unique geometrical and electronic structure changes. Our results show a clue for the tunability of the electronic structure of nanoparticles by controlling the arrangement in the nanoparticles.

Modified gastric pull-up reconstructions following pharyngolaryngectomy with total esophagectomy

Reconstruction following pharyngolaryngectomy with total esophagectomy is a challenging surgery to perform. Between April 2008 and August 2012, three types of modified gastric pull-up reconstruction procedures, including a gastric tube creation combined with a free jejunal transfer (n = 7), elongated gastric tube creation with vascular anastomoses (n = 2) and pedunculated gastric tube creation with Roux-en-Y anastomosis (n = 5), were performed after pharyngolaryngectomy with total esophagectomy. To clarify feasibility of these reconstructive methods, we retrospectively analyzed the short-term outcomes. There were no graft failures. Salivary fistulae were observed in two cases after high pharyngoenteral anastomoses due to oropharyngeal extension of hypopharyngeal cancers. Overall morbidity rate was 21.4%, and no deaths occurred. Although the operation time was shortest for pedunculated gastric tube reconstructions, morbidity rates were similar among all methods. All three types of modified gastric pull-up reconstruction procedures can be performed safely. We can choose one of these methods according to the tumor status and the patient condition, understanding advantages and disadvantages of each procedure.

Plasma CD147 reflects histological features in patients with lupus nephritis

OBJECTIVE

A glycosylated transmembrane protein, CD147, has been implicated in regulating lymphocyte responsiveness and leukocyte recruitment. As lupus nephritis (LN) often follows a relapsing-remitting disease course, accurate understanding of the disease activity would be extremely helpful in improving prognosis. Unfortunately, neither clinical nor serological data can accurately reflect the histological features of LN. The present study investigated whether CD147 can accurately predict pathological features of LN.

METHODS

Plasma and spot urine samples were collected from 64 patients who underwent renal biopsy between 2008 and 2011. Disease activity for LN tissues was evaluated using the biopsy activity index, and compared to levels of biomarkers including CD147.

RESULTS

In LN tissues, CD147 induction was striking in injured glomeruli and infiltrating inflammatory cells, but not in damaged tubules representing atrophy. Plasma CD147 levels accurately reflected the histological disease activity. However, prediction using a single molecule would be quite difficult because of the complex pathogenesis of LN. The diagnostic accuracy of multiplex parameters indicated that the combination including plasma CD147 might yield excellent diagnostic abilities for guiding ideal LN therapy.

CONCLUSION

Plasma CD147 levels might offer useful insights into disease activity as a crucial biomarker in patients with LN.

Radiofrequency ablation for pulmonary metastases from esophageal squamous cell carcinoma

Radiofrequency ablation (RFA) is increasingly being used for the treatment of intrathoracic malignancies. Although RFA has been found to be promising in the treatment of lung metastases from some types of neoplasms, little is known concerning its clinical significance in the treatment of pulmonary metastasis from esophageal squamous cell carcinoma (ESCC). This retrospective study evaluated the feasibility, safety, and effectiveness of computed tomography-guided RFA for pulmonary metastasis from ESCC. A series of 10 ESCC patients with 17 pulmonary tumors were included. Correct placement of the ablation device into the target tumor proved to be feasible in all tumors (100%). The mean visual analog scale score, with values that ranged from 0 (no pain) to 10 (worst pain possible), was 1. This suggested that this procedure was well tolerated. No procedure-related deaths occurred. A pneumothorax needing drainage was a major complication in two patients. Local control of ablated tumor lasting for at least 1 year was achieved in 10 (83%) of 12 assessable tumors. Although locoregional recurrences developed in two tumors, these lesions could be recontrolled by repeat treatment with RFA. Three patients died of recurrent disease. The predicted 1- and 2-year overall survival rates after lung RFA were 77.8% and 62.2%, respectively. Percutaneous computed tomography-guided RFA yielded relatively high levels of local control in patients with pulmonary metastases from ESCC and was associated with an acceptable level of complications. It was concluded that a prospective study will be necessary to evaluate the effectiveness of a combination of systemic therapy and RFA for ESCC lung metastases.

CD44s signals the acquisition of the mesenchymal phenotype required for anchorage-independent cell survival in hepatocellular carcinoma

Background:

Circulating tumour cells (CTCs) have an important role in metastatic processes, but details of their basic characteristics remain elusive. We hypothesised that CD44-expressing CTCs show a mesenchymal phenotype and high potential for survival in hepatocellular carcinoma (HCC).

Methods:

Circulating CD44⁺CD90⁺ cells, previously shown to be tumour-initiating cells, were sorted from human blood and their genetic characteristics were compared with those of tumour cells from primary tissues. The mechanism underlying the high survival potential of CD44-expressing cells in the circulatory system was investigated in vitro.

Results:

CD44⁺CD90⁺ cells in the blood acquired epithelial–mesenchymal transition, and CD44 expression remarkably increased from the tissue to the blood. In Li7 and HLE cells, the CD44^high population showed higher anoikis resistance and sphere-forming ability than did the CD44^low population. This difference was found to be attributed to the upregulation of Twist1 and Akt signal in the CD44^high population. Twist1 knockdown showed remarkable reduction in anoikis resistance, sphere formation, and Akt signal in HLE cells. In addition, mesenchymal markers and CD44s expression were downregulated in the Twist1 knockdown.

Conclusions:

CD44s symbolises the acquisition of a mesenchymal phenotype regulating anchorage-independent capacity. CD44s-expressing tumour cells in peripheral blood are clinically important therapeutic targets in HCC.