Molecular Mechanisms and New Treatment Strategies for Non-Alcoholic Steatohepatitis (NASH)

Non-alcoholic steatohepatitis (NASH) is a severe form of non-alcoholic fatty liver disease (NAFLD), in which most patients exhibit non-progressive, non-alcoholic fatty liver (NAFL) attributable to simple steatosis. Multiple hits, including genetic differences, fat accumulation, insulin resistance and intestinal microbiota changes, account for the progression of NASH. NAFLD is strongly associated with obesity, which induces adipokine secretion, endoplasmic reticulum (ER) and oxidative stress at the cellular level, which in turn induces hepatic steatosis, inflammation and fibrosis. Among these factors, gut microbiota are acknowledged as having an important role in initiating this multifactorial disease. Oxidative stress is considered to be a key contributor in the progression from NAFL to NASH. Macrophage infiltration is apparent in NAFL and NASH, while T-cell infiltration is apparent in NASH. Although several clinical trials have shown that antioxidative therapy with vitamin E can effectively control hepatitis pathology in the short term, the long-term effects remain obscure and have often proved to be ineffective in many other diseases. Several long-term antioxidant protocols have failed to reduce mortality. New treatment modalities that incorporate current understanding of NAFLD molecular pathogenesis must be considered.     

An Improved Method for Analysis of Glucosylceramide Species Having cis-8 and trans-8 Isomers of Sphingoid Bases by LC–MS/MS

High-performance liquid chromatography–electrospray ionization tandem mass spectrometry (HPLC–ESI–MS/MS) approaches have enabled high selectivity and sensitivity for the identification and quantification of glucosylceramide molecular species. Here we demonstrate that HPLC–ESI–MS/MS is an efficient method for characterizing plant glucosylceramide species having the cis-8 and trans-8 isomers of sphingoid bases. Complete baseline separation was achieved using a high-carbon-content octadecylsilyl column and a simple binary gradient comprising methanol and water. The result of 2-hydroxy fatty acid composition achieved by HPLC–ESI–MS/MS was compared with that achieved by gas chromatography with flame ionization detection (GC–FID), indicating that the two methods yield similar molar compositions. The current method should be applicable to seeking the active components of glucosylceramide species from plant materials in response to biological challenges.     

Formation and self-breaking mechanism of stable atom-sized junctions

The self-breaking mechanism of gold junctions is studied by investigating stability of the atom-sized contacts. The single atom contact lifetime increases from about 0.02 to 200 s upon decreasing the junction stretching speed, while at the same time, the breaking force diminishes logarithmically. We find that the junction self-breaking processes involve sufficient atomic rearrangements, which thereby allow complete self-compensation of externally introduced strain at 0.8 pm/s. The present results have important implications on fabrication of stable single molecule junctions.     

A cytoplasmic xylanase (XynX) of Aeromonas caviae ME-1 is released from the cytoplasm to the periplasm by osmotic downshock

Aeromonas caviae ME-1 is a multiple xylanase-producing gram-negative bacterium which was isolated from the gut contents of a wild silkworm, Samia cynthia pryeri. One of the xylanases produced by A. caviae ME-1, XynX (38 kDa, family 10 xylanase), hydrolyzes xylan to xylobiose and xylotetraose as final degradation products. Generally, xylanases are extracellular or cell surface enzymes. However, XynX is not exported to the extracellular fluid by A. caviae ME-1 and an Escherichia coli transformant harboring the xynX gene. In this study, we investigated the intracellular localization of XynX in A. caviae ME-1 and an E. coli transformant. XynX was found in the cytoplasm when the cells were grown under normal culture conditions. However, XynX was released from the cytoplasm to the periplasm during osmotic downshock. This release of XynX in the E. coli transformant was blocked in the presence of gadolinium chloride, which has been reported to be an inhibitor of bacterial mechanosensitive channels.     

Developmental changes in the kinetics of glucose and urea in Holstein calves

Because weaning is the point when the nutrient composition of feed changes for the neonatal ruminant, the present experiment was conducted to assess the developmental changes in the kinetics of glucose and urea over this period, using stable isotopes of glucose and urea, at 4, 13, and 24 wk in calves. Plasma concentrations of nonesterified fatty acids, amino-N, urea-N, and insulin-like growth factor-I increased, but that of growth hormone decreased with age. The plasma glucose concentration increased at 13 wk of age and thereafter decreased at 24 wk of age. The glucose irreversible loss and recycling rates were significantly higher at 4 wk of age than at 13 and 24 wk of age. On the other hand, the irreversible loss and recycling rates of urea, as well as the urea pool size, were higher at 24 wk of age than at 4 and 13 wk. It is concluded that weaning at 6 wk is the pivotal time for the alteration of glucose kinetics. However, the aging process, but not weaning, is important for changes in the kinetics of urea in calves.     

The effect of pressure during sintering on the strength and the fracture toughness of hydroxyapatite ceramics

Hydroxyapatite (HA) is known to be biocompatible and osteoconductive, and can be synthesized chemically. The objective of the present study is to clarify the effect of pressure during sintering on the mechanical properties of HA. HA was sintered using a hot press system at a uniaxial pressure ranging from 7.81 to 62.5 MPa at a maximum temperature of 1200^∘C with a heating rate of 10^∘C/min. The density of the HA increased with increasing pressure and peaked at the sintering pressure of 31.2 MPa. Four-points bending tests and fracture toughness measurements with indentation method were conducted to clarify the effect of sintering pressure. Bending strength decreased at the pressure > 31.2 MPa. This result indicates that residual stress generated during sintering process became larger with increasing pressure. Fracture toughness were also lower with high density HA.     

Microlens arrays for integral imaging system

When designing a system capable of capturing and displaying 3D moving images in real time by the integral imaging (II) method, one challenge is to eliminate pseudoscopic images. To overcome this problem, we propose a simple system with an array of three convex lenses. First, the lateral magnification of the elemental optics and the expansion of an elemental image is described by geometrical optics, confirming that the elemental optics satisfies the conditions under which pseudoscopic images can be avoided. In using the II method, adjacent elemental images must not overlap, a condition also satisfied by the proposed optical system. Next, an experiment carried out to acquire and display 3D images is described. The real-time system we have constructed comprises an elemental optics array with 54 H x 59 V elements, a CCD camera to capture a group of elemental images created by the lens array, and a liquid crystal panel to display these images. The results of the experiment confirm that the system produces orthoscopic images in real time, and thus is effective for real-time application of the II method.     

A field evaluation of in situ biodegradation of trichloroethylene through methane injection

A field study of biodegradation of trichloroethylene (TCE) through methane injection was conducted at the yard of a home in Japan. Methane was selected as the safest substrate for injection into groundwater. Methane, oxygen, nitrate, and phosphate were introduced into groundwater contaminated with 220 microg/L of TCE. After a week of biostimulation, methane concentrations gradually decreased below the detection limit. Methane oxidizing bacterial numbers increased from 10 to 10(4) cells/mL with methane consumptions. During methane injection. 10-20% of TCE removal was observed. The biotransformation yield was 3-13 mgTCE/gCH4 in this field test. After methane injections were stopped, TCE removal was not observed. These results indicated that bioremediation using methane was useful as a safe technology for a TCE-contaminated area near homes.     

Hydraulic fracture reopening pressure and the estimation of maximum horizontal stress

In hydrofracture stress measurements, the magnitude of the maximum horizontal stress, S_H, is commonly estimated from the borehole pressure required to reopen an induced axial crack. Examination of the processes which govern the borehole pressure history recorded during the reopening cycle of such tests indicates two sources of error in the estimates of S_H derived using the conventional method proposed by Bredehoeft et al. [Bredehoeft JD, Wolff RG, Keys WS and Shutter E, 1976, Colorado. Geol. Soc. Amer. Bull., 87, 250–8]. The first arises from the failure to include a term arising from pressure penetration into the crack prior to reopening in the force balance acting across the mouth of the induced axial cracks. The problem can be remedied by using a modified ‘reopening equation’ which includes pressure penetration of the crack. The second source of error is more problematic and concerns the correct identification of the true reopening pressure from the borehole pressure records. Analysis of the process of reopening aided by numerical simulations shows that the true reopening pressure is generally less than the apparent (i.e. that detected) reopening pressure. The discrepancy between true and apparent reopening pressures increases with larger hydraulic compliance of the test equipment. The compliance in question refers to that of the fluid volume between the flow meter and the crack mouth(s). Simulation of a pair of 1 m high axial cracks with 2 μm residual hydraulic aperture in a 100 mm borehole, indicates that the system compliance must be reduced to 5×10⁻⁷ m³/MPa to enable the true reopening pressure to be estimated to better than 10%, at flow rate is less than 10⁻⁴ m³/s. This is several orders of magnitude less than applies to conventional hydrofracture systems, but is attainable for tests in small holes at shallow depth by making relatively minor system modifications. Tests at greater depth, however, would seem to require downhole measurement of flow at the packers. We validate our assertions with a field test in which reopening pressure was determined mechanically and hydraulically.