Helicobacter pylori induces proinflammatory cytokines and major histocompatibility complex class II antigen in mouse gastric epithelial cells

Although Helicobacter pylori has been reported to stimulate the release of various cytokines from gastric tissue, it remains unknown whether normal and nontumorous gastric epithelial cells produce these cytokines. Therefore, in this study, we used a normal mouse gastric surface mucous cell line (GSM06) to determine whether gastric epithelial cells produce proinflammatory cytokines in response to H. pylori. The expression of MHC class II antigen was also examined, to investigate whether gastric epithelial cells participate in the immune response to H. pylori. In the study, GSM06 cells were incubated with H. pylori or its lipopolysaccharide (LPS). Proinflammatory cytokines were detected by Northern and Western blot analysis. The expression of MHC class II antigen was examined by fluorescence activated cell sorter (FACS) analysis. Genetic expression of proinflammatory cytokines such as interleukin-1alpha, tumor necrosis factor-alpha, and cytokine-induced neutrophil chemoattractant-2beta was enhanced by both intact and sonicated H. pylori, but not by H. pylori LPS. The expression of MHC class II antigen was induced by H. pylori more strongly than by interferon-gamma. We conclude that H. pylori induces the expression of proinflammatory cytokines and MHC class II antigen in gastric epithelial cells. Gastric epithelial cells may act as antigen-presenting cells and participate in the immune response to H. pylori infection.     

Carrier-mediated entry of 4-methylumbelliferyl sulfate: characterization by the multiple-indicator dilution technique in perfused rat liver

The hepatocellular entry of 4-methylumbelliferyl sulfate (4MUS) a highly ionized and highly bound anion capable of futile cycling, was examined in the single-pass albumin-free perfused rat liver preparation. Desulfation of 4MUS to 4-methylumbelliferone (4MU) was verified in vitro to be a low-affinity, high-capacity process (Km = 731 micromol/L; Vmax = 414 nmol min(-1) g(-1) liver). With 4MUS given to the perfused rat liver, sulfation of 4MU, the formed metabolite, was attenuated in the presence of 2,6-dichloro-4-nitrophenol (DCNP), a sulfation inhibitor, and when sulfate ion was substituted by chloride ion. 4MU sulfation, being a high-affinity system, was reduced most effectively at the lowest 4MUS concentration (15 micromol/L) used, evidenced by the increased (24%) net hepatic extraction ratio of 4MUS and reduced utilization (72%) of infused tracer 35SO4(2-) by 4MU for 4MU35S formation. Single-pass multiple indicator dilution (MID) studies were thus conducted under identical conditions (DCNP and absence of inorganic sulfate), with injection of [3H]4MUS and a set of noneliminated vascular and cellular reference indicators into the portal vein (prograde) or hepatic vein (retrograde), against varying background bulk concentrations of 4MUS (5 to 900 micromol/L). The steady-state removal rate of 4MUS and formation rates of 4MU and its glucuronide conjugate (4MUG) were not altered with perfusion flow direction, suggesting the presence of even or parallel distributions of 4MUS desulfation and 4MU glucuronidation activities. When the outflow dilution profile of [3H]4MUS was evaluated with the barrier-limited model of Goresky, a slight red cell carriage effect was found for 4MUS. The permeability surface area product for cellular entry for prograde showed a dramatic concentration-dependent decrease (from 0.13 to 0.01 mL sec(-1) g(-1), or 7.4 to 0.56 times the blood perfusate flow rate) and was resolved as saturable and nonsaturable components, while data for retrograde were more scattered, varying from 2.8 to 1 times the blood perfusate flow rate. Efflux (coefficient = 0.0096 +/- 0.0024 and 0.0088 +/- 0.0062 mL sec(-1) g(-1), respectively) was relatively insensitive to concentration and flow direction. The same was observed for the removal capacity for metabolism and excretion (sequestration coefficient: for prograde, 0.0056 +/- 0.0017 mL sec(-1) g(-1); for retrograde, 0.0056 +/- 0.003 mL sec(-1) g(-1)). The decrease in the apparent partition coefficient (ratio of 4MUS concentration estimated in tissue to unbound plasma concentration) and the increase in relative throughput component with concentration further substantiate the claim on the presence of concentrative processes at the sinusoidal membrane.     

A potential molecular approach to ex vivo hematopoietic expansion with recombinant epidermal growth factor receptor-expressing adenovirus vector

Ex vivo expansion of hematopoietic stem cell (HSC) is an attractive technology for its potency of a variety of clinical applications. Such a technology has been achieved to some extent with combinations of various cytokines or continuous perfusion cultures. However, much more improvement is required especially for expansion of primitive hematopoietic progenitors. We propose here a novel molecular approach that might have the potential to compensate the current expansion. We designed an adenovirus vector to transiently express human epidermal growth factor receptor (EGFR), which is known to transduce only a mitogenic, but not a differentiation signal to mouse bone marrow cells on human purified CD34+ peripheral blood (PB) cells, and tried to expand these cells with EGF ex vivo. Because we found that exposure of CD34+ PB cells to cytokines induced surface expression of adenovirus-internalization receptor and rendered these cells permissive to adenovirus infection, we infected these cells with the adenovirus vector carrying EGFR gene in the presence of cytokines. Two-color flow cytometric analysis demonstrated that 60.3% +/- 22.4% of CD34+ cells expressed the adenovirus-mediated EGFR. Moreover, long-term culture-initiating cell assay showed that adenovirus vector could transduce more primitive progenitors. Subsequently, we tried to expand these cells in suspension culture with EGF for 5 days. Methylcellulose clonal assay showed that EGF induced 5.0- +/- 2.4-fold proliferation of the colony-forming unit pool during 5 days of expansion. The simple procedure of efficient adenovirus gene delivery to immature hematopoietic cells proved promising, and this technique was potentially applicable for a novel strategy aiming at ex vivo expansion of hematopoietic progenitors.     

A simple device of chest wall reconstruction

We devised a simple method of chest wall reconstruction in two cases of malignant tumor of the chest. We strained a suture (adsorbable or monofilament) to the intact ribs above and below the defect and fixed the sheets of Marlex mesh in double layers and closed the skin without any myocutaneous flap. The postoperative course was uneventful. This device is simple and effective method to maintain the stability of the chest wall defect.     

Design and analysis of permanent magnet-type bearingless motors

Magnetic bearings have been applied to high speed and high power electric machines for machine tools, turbomolecular pumps, etc. Bearingless motors can be expected to realize high speed and high power ratings because magnetic bearing functions are integrated into high-speed motors, which results in a simplified structure with short shaft length. In this paper, permanent magnet type bearingless motors, having built-in capability to achieve high power factor and high efficiency, are proposed. The shaft is suspended and centered by electromagnetic forces produced by currents in the additional radial force windings of the stator slots. At first the relationships of these radial forces, currents and voltages are derived analytically. Moreover, the relationships between radial forces and permanent magnet thickness are found. The optimal permanent magnet thickness is determined. The ratio of radial force over current as well as the peak air-gap flux density are discussed. These relationships are confirmed by prototype machines