The asymmetry of antimatter in the proton.

The fundamental building blocks of the proton-quarks and gluons-have been known for decades. However, we still have an incomplete theoretical and experimental understanding of how these particles and their dynamics give rise to the quantum bound state of the proton and its physical properties, such as its spin1. The two up quarks and the single down quark that comprise the proton in the simplest picture account only for a few per cent of the proton mass, the bulk of which is in the form of quark kinetic and potential energy and gluon energy from the strong force2. An essential feature of this force, as described by quantum chromodynamics, is its ability to create matter-antimatter quark pairs inside the proton that exist only for a very short time. Their fleeting existence makes the antimatter quarks within protons difficult to study, but their existence is discernible in reactions in which a matter-antimatter quark pair annihilates. In this picture of quark-antiquark creation by the strong force, the probability distributions as a function of momentum for the presence of up and down antimatter quarks should be nearly identical, given that their masses are very similar and small compared to the mass of the proton3. Here we provide evidence from muon pair production measurements that these distributions are considerably different, with more abundant down antimatter quarks than up antimatter quarks over a wide range of momenta. These results are expected to revive interest in several proposed mechanisms for the origin of this antimatter asymmetry in the proton that had been disfavoured by previous results4, and point to future measurements that can distinguish between these mechanisms.

Ultrafast Electron-Electron Scattering in Metallic Phase of 2H-NbSe_{2} Probed by High Harmonic Generation.

Electron-electron scattering on the order of a few to tens of femtoseconds plays a crucial role in the ultrafast electron dynamics of conventional metals. When mid-infrared light is used for driving and the period of light field is comparable to the scattering time in metals, unique light-driven states and nonlinear optical responses associated with the scattering process are expected to occur. Here, we use high-harmonics spectroscopy to investigate the effect of electron-electron scattering on the electron dynamics in thin film 2H-NbSe_{2} driven by a mid-infrared field. We observed odd-order high harmonics up to 9th order as well as a broadband emission from hot electrons in the energy range from 1.5 to 4.0 eV. The electron-electron scattering time in 2H-NbSe_{2} was estimated from the broadband emission to be almost the same as the period of the mid-infrared light field. A comparison between experimental results and a numerical calculation reveals that competition and cooperation between the driving and scattering enhances the nonperturbative behavior of high harmonics in metals, causing a highly nonequilibrium electronic state corresponding to several thousand Kelvin.

Influence of concurrent and staggered dosing of semi-solid nutrients on the pharmacokinetics of orally administered carbamazepine in rats.

In the present study, we examined the effects of concurrent and staggered dosing of PG-soft ace-MP TM (PG), novel semi-solid enteral nutrients, on the pharmacokinetics of orally administered carbamazepine (CBZ) in rats due to the high possibility of drug interaction during the absorption process. The pharmacokinetic behavior of CBZ was considerably altered when administered concurrently with PG. The maximum serum CBZ concentration (Cmax) significantly decreased and the mean residence time (MRT) significantly increased. The elimination constant (ke) also significantly increased, but there were no significant changes in the area under the serum CBZ concentration versus time curve (AUC) and the time to reach Cmax (Tmax). However, these changes in the pharmacokinetic parameters were eliminated by waiting 20 min, the time interval equivalent to the Tmax described above, between CBZ administration and PG dosing. This study suggested that PG interferes with CBZ absorption from the digestive tract, although staggered administration of CBZ and PG prevented their interaction.

Urinary biomarkers of kidney tubule injury, risk of acute kidney injury, and mortality in patients with acute ischaemic stroke treated at a stroke care unit.

BACKGROUND AND PURPOSE: Urinary liver-type fatty-acid binding protein (L-FABP), which is a biomarker of kidney tubule injury, has been studied extensively and established as a risk marker of acute kidney injury (AKI). The aim of this study was to investigate whether kidney tubule injury is associated with the development of AKI and mortality in patients with acute ischaemic stroke. METHODS: Acute ischaemic stroke patients hospitalized in the stroke care unit (SCU) within 24 h after symptom onset were prospectively investigated. AKI was defined on the basis of Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Baseline urinary L-FABP was measured on admission. We evaluated the associations among urinary L-FABP, incidence of AKI, and 90-day mortality adjusted for renal function, albuminuria and other potentially predictive variables, using multivariable analysis. RESULTS: In total, 527 acute ischaemic stroke patients (342 men, median age 74 years) were enrolled in the study. Twenty-seven patients (5.1%) experienced AKI within 7 days of admission. In the univariate analysis, high urinary L-FABP level had positive associations with AKI [53.8 µg/g creatinine (Cr) vs. 3.9 µg/g Cr; P < 0.001] and 90-day mortality (15.5 µg/g Cr vs. 4.0 µg/g Cr; P < 0.001). In the multivariate analysis, elevated urinary L-FABP level (per 10-µg/g Cr increase) was independently associated with AKI (odds ratio 1.225, 95% confidence interval (CI) 1.083-1.454; P = 0.003) and 90-day mortality (hazard ratio 1.091, 95% CI 1.045-1.138; P < 0.001). CONCLUSION: Urinary biomarkers of kidney tubule injury are independently associated with the development of AKI and 90-day mortality in patients with acute ischaemic stroke treated at the SCU.

Reduced cytotoxicity in doxorubicin-exposed HepG2 cells pretreated with menthol due to upregulation of P-glycoprotein.

The aim of the present study was to examine changes in the expression and activity of P-glycoprotein (P-gp) in human hepatocellular carcinoma HepG2 cells after exposure to menthol, and their relationship to the cytotoxicity of and apoptotic responses to doxorubicin (DOX), a substrate of P-gp, in the cells. The expression of P-gp in HepG2 cells was significantly increased by menthol treatment. Intracellular accumulation of DOX in HepG2 cells was significantly lower in the menthol-treated group than in the control group, but this phenomenon was abolished in the presence of verapamil. Decreased cell viability by DOX was significantly attenuated by 24-h menthol treatment prior to DOX exposure, which coincided with the changes in mRNA expression of Bcl-xl and caspase-3. These results demonstrate that menthol causes hepatocellular carcinoma cells to acquire resistance to DOX by increasing its efflux through the upregulation of P-gp.

Clinical and experimental studies of intraperitoneal lipolysis and the development of clinically relevant pancreatic fistula after pancreatic surgery.

BACKGROUND: Visceral obesity is one of the risk factors for clinically relevant pancreatic fistula after pancreatic resection. The objective of this study was to evaluate the impact of intraperitoneal lipolysis on postoperative pancreatic fistula. METHODS: The degree of intraperitoneal lipolysis was investigated by measuring the free fatty acid concentration in drain discharge in patients after pancreatic resection. An experimental pancreatic fistula model was prepared by pancreatic transection, and the impact of intraperitoneal lipolysis was evaluated by intraperitoneal administration of triolein (triglyceride) with, or without orlistat (lipase inhibitor). RESULTS: Thirty-three patients were included in the analysis. The free fatty acid concentration in drain discharge on postoperative day 1 was significantly associated with the development of a clinically relevant pancreatic fistula (P = 0·004). A higher free fatty acid concentration in drain discharge was associated with more visceral adipose tissue (P = 0·009). In the experimental model that included 98 rats, intraperitoneal lipolysis caused an increased amount of pancreatic juice leakage and multiple organ dysfunction. Intraperitoneal administration of a lipase inhibitor reduced lipolysis and prevented deterioration of the fistula. CONCLUSION: Intraperitoneal lipolysis significantly exacerbates pancreatic fistula after pancreatic resection. Inhibition of lipolysis by intraperitoneal administration of a lipase inhibitor could be a promising therapy to reduce clinically relevant postoperative pancreatic fistula. Surgical relevance Clinically, there are two types of pancreatic fistula after pancreatic resections: harmless biochemical leak and harmful clinically relevant pancreatic fistula. Visceral obesity is one of the known risk factors for clinically relevant pancreatic fistula; however, the underlying mechanisms remained to be elucidated. Patients with clinically relevant pancreatic fistula had a higher free fatty acid concentration in the drain discharge, suggesting a relationship between intraperitoneal lipolysis and pancreatic fistula. The experimental model of pancreatic fistula demonstrated that intraperitoneal lipolysis caused deterioration in pancreatic fistula, suggesting that intraperitoneal lipolysis is one of the mechanisms that drives biochemical leakage to clinically relevant pancreatic fistula. Intraperitoneal administration of a lipase inhibitor prevented lipolysis as well as pancreatic fistula deterioration in the experimental model, suggesting a future clinical application for lipase inhibitors in prevention of clinically relevant pancreatic fistula.

Downregulation of organic cation transporter 1 and breast cancer resistance protein with the induction of Pregnane X receptor in rat kidney impaired by doxorubicin.

Transporters expressed in the kidney play an important role in the excretion of endogenous substances and chemical drugs. The Pregnane X receptor (PXR) has been reported to be involved in regulating the expression of numerous transporters. In the present study, we examined the alteration in expression level of PXR, organic cation transporter 1 (OCT1) and breast cancer resistance protein (BCRP) in renal cell lines of rat origin and the kidney of rats when damaged by doxorubicin (DOX). The expression level of PXR in renal tubular epithelium NRK-52E cells was significantly increased by DOX at a concentration confirmed to cause cellular damage. The expression levels of OCT1 and BCRP were significantly lower in the DOX-treated cells than in the untreated cells. In model rats with DOX-induced nephrotoxicity, the alterations in renal expression of PXR, OCT1 and BCRP were similar to those in NRK-52E cells, although there was a difference in the degree of the changes.

Spermatic and oxidative profile of domestic cat (Felis catus) epididymal sperm subjected to different cooling times (24, 48 and 72 hours).

Cooling stored epididymal samples for several days allows facilities to transport and process genetic material post-mortem. Improvements to this practice allow the preservation of sperm from domestic cats, which are the ideal study model for wild felids. However, the modifications in spermatic features and the oxidative profile are not fully understood in cats. This information is necessary for the development of biotechniques, such as new extenders for cryopreservation. Therefore, the purpose of this study was to evaluate the spermatic and oxidative profile in samples from the epididymal cauda of domestic cats cooled at 5°C for 24, 48 and 72 hr. Spermatozoa were collected from the epididymis cauda. Evaluations consisted of computer-assisted sperm analysis (CASA), plasma membrane integrity (eosin/nigrosin), acrosome integrity (fast green/rose bengal), sperm morphology, sperm DNA integrity (toluidine blue), mitochondrial activity (3'3 diaminobenzidine), activity of the antioxidant enzymes glutathione peroxidase (GPx) and superoxide dismutase (SOD), measurement of lipid peroxidation (TBARS) and protein oxidation. A decrease in sperm motility parameters was observed after 72 hr of cooling (i.e. total and progressive) with a higher percentage of minor (37.7 ± 6.3%) and total defects (53.4 ± 6.3%). Additionally, a decrease in high mitochondrial activity (Class I: 16.6 ± 2.2%) occurred after 72 hr. The decrease in motility rates after a long cooling time probably was caused by the increase in sperm abnormalities. A long cooling time causes cold shock and mitochondrial exhaustion, but there was no observed change with the oxidative stress condition. Therefore, cat epididymal sperm stored at 5°C appear to maintain a high quality for up to 48 hr of cooling time.

Higher gene expression of CYP1A2, 2B1 and 2D2 in the brain of female compared with male rats.

Cytochrome P450 (CYP) in the brain plays an essential role in the local metabolism of various compounds, including clinically used drugs, toxins, and endogenous substances. In the present study, we compared the expression profiles of mRNAs for several CYP subtypes in the brain between male and female rats. The expression of CYP1A2, CYP2B1, and CYP2D2 in females was significantly higher than that in males. On the other hand, the expression level of the other CYP subtypes examined in the male brain was similar to that in the female brain. These results strongly suggest that marked gender differences exist in the expression profiles of some CYP subtypes in rat brain.

Taurine as a protective agent for 5-fluorouracil-induced hepatic damage related to oxidative stress.

5-Fluorouracil (5-FU) is a pyrimidine analog widely used for the treatment of various cancers, but often causes hepatic damage in clinical practice. In this study, we examined the influence of taurine on 5-FU-induced hepatotoxicity in mice with respect to changes in oxidative stress. Elevations in the aspartate aminotransferase and alanine aminotransferase serum levels after 5-FU administration were significantly suppressed in a dosedependent manner by concurrent treatment with taurine. The activity of superoxide dismutase and reduced glutathione content in the liver were significantly decreased following treatment with 5-FU alone, but these changes were markedly inhibited by the administration of taurine. Our findings suggest that taurine protects against 5-FU-induced hepatotoxicity by suppressing oxidative stress.

Depletion of SIRT6 causes cellular senescence, DNA damage, and telomere dysfunction in human chondrocytes.

OBJECTIVE: SIRT6, a member of the sirtuin family of nicotinamide adenine dinucleotide (NAD(+))-dependent protein deacetylases, has been implicated as a key factor in aging-related diseases. However, the role of SIRT6 in chondrocytes has not been fully explored. The purpose of this study was to examine the role of SIRT6 in human chondrocytes by inhibiting SIRT6 in vitro. DESIGN: First, the localization of SIRT6 and proliferation cell nuclear antigen (PCNA) in human cartilages was examined by immunohistochemistry. Next, SIRT6 was depleted by RNA interference (RNAi), and the effect of SIRT6 depletion on changes in gene expression, protein levels, proliferation, and senescence in human chondrocytes was assessed. Furthermore, to detect DNA damage and telomere dysfunction, γH2AX foci and telomere dysfunction-induced foci (TIFs) were examined using immunofluorescence microscopy. The protein levels of two mediators for DNA damage induced-senescence, p16 and p21, were examined by western blotting. RESULTS: Immunohistochemical analysis showed SIRT6 was preferentially expressed in the superficial zone chondrocytes and PCNA-positive cluster-forming chondrocytes in the osteoarthritic cartilage tissue samples. Real-time PCR analysis showed that matrix metalloproteinase 1 (MMP-1) and MMP-13 mRNA were significantly increased by SIRT6 inhibition. Moreover, SIRT6 inhibition significantly reduced proliferation and increased senescence associated ß-galactosidase (SA-ß-Gal)-positive chondrocytes; it also led to increased p16 levels. Immunofluorescence microscopy showed that γH2AX foci and TIFs were increased by SIRT6 inhibition. CONCLUSION: Depletion of SIRT6 in human chondrocytes caused increased DNA damage and telomere dysfunction, and subsequent premature senescence. These findings suggest that SIRT6 plays an important role in the regulation of senescence of human chondrocytes.

Spin-dependent acoustic response in the nonunitary A1 and A2 phases of superfluid 3He under high magnetic fields.

The transverse acoustic impedance of superfluid ^{3}He was measured in the A1 and A2 phases up to 13 T to investigate the surface states in nonunitary superfluids. The temperature dependence of the impedance was much larger in the A1 phase than in the A2 phase. This nonsymmetric behavior indicates that momentum exchange with walls for spin-down surface states is quite different from that for spin-up surface states. The spin-dependent response might be a reflection of an essential feature of the nonunitary states where gap amplitudes depend on spin states. Weak-coupling theories ignore any spin-dependent processes and do not account for the nonsymmetric behavior.

Altered acetylation of proteins in patients with rheumatoid arthritis revealed by acetyl-proteomics.

OBJECTIVES: Post-translational modifications (PTMs) are often critical for the function of proteins as well as antigenicity of proteins. We here tried to elucidate alteration of PTMs in Rheumatoid arthritis (RA), focusing on acetylation. We applied acetyl-proteomics to peripheral blood mononuclear cells (PBMCs) to elucidate PTM difference between patients with RA and healthy donors. METHODS: Proteins, extracted from peripheral blood mononuclear cells (PBMCs) of 7 RA patients and 7 healthy donors, were separated by 2-dimansional electrophoresis. Acetylation ratios of each protein spot were estimated by the combination of Sypro Ruby staining and anti-acetylated lysine antibodies. Proteins highly acetylated in the RA group were identified by mass spectrometry. Focusing on α-enolase (ENO1), one of the identified proteins, involvement of histone deacetylases (HDACs) in the high acetylation was investigated. Furthermore, the effects of acetylation on the activity of ENO1 were investigated. RESULTS: In PBMCs from the patients with RA, 29 acetylated protein spots were detected. One of highly acetylated proteins in the RA patients was identified as ENO1. The acetylation of ENO1 was found to be regulated in part by HDAC1. The enzymatic activity of ENO1 was up-regulated by acetylation. CONCLUSIONS: Highly acetylated ENO1 may play roles in the pathophysiology of RA through the maintenance of activated lymphocytes by increasing glycolysis-derived energy supply.

Salvage chemoradiotherapy for locally advanced esophageal carcinomas.

'Salvage chemoradiotherapy (CRT)' was introduced in 2005 to treat thoracic esophageal carcinomas deemed unresectable based on the intraoperative findings. The therapeutic concept is as follows: the surgical plan is changed to an operation that aims to achieve curability by the subsequent definitive CRT. For this purpose, the invading tumor is resected as much as possible, and systematic lymph node dissection is performed except for in the area around the bilateral recurrent nerves. The definitive CRT should be started as soon as possible and should be performed as planned. We hypothesized that this treatment would be feasible and provide good clinical effects. We herein verified this hypothesis. Twenty-seven patients who received salvage CRT were enrolled in the study, and their clinical course, therapeutic response, and prognosis were evaluated. The patients who had poor oral intake because of esophageal stenosis were able to eat solid food soon after the operation. The radiation field could be narrowed after surgery, and this might have contributed to the high rate of finishing the definitive CRT as planned. As a result, the overall response rate was 74.1%, and 48.1% of the patients had a complete response. No patient experienced fistula formation. The 1-, 3-, and 5-year overall survival rates were 66.5%, 35.2%, and 35.2%, respectively. Salvage CRT had clinical benefits, such as the fact that patients became able to have oral intake, that fistula formation could be prevented, that the adverse events associated with the definitive CRT could be reduced, and that prognosis of the patients was satisfactory. Although the rate of recurrent nerve paralysis was relatively high even after the suspension of aggressive bilateral recurrent nerve lymph node dissection, and the rate of the progressive disease after the definitive CRT was high, salvage CRT appears to provide some advantages for the patients who would otherwise not have other treatment options following a non-curative and residual operation.