We investigated the effect of probucol on the intracellular pH (pHi) and proliferation of human umbilical vein endothelial cells (HUVEC), as well as their production of prostacyclin (PGI
2). The ...addition of probucol produced a biphasic shift in pHi, with a brief initial acidification followed by a rapid alkaline shift. After pretreatment with EGTA, the initial decrease in pHi was abolished, and the subsequent increase was inhibited. After pretreatment with amiloride, only the increase of pHi was abolished. These results suggest that the probucol-induced increase of pHi was mainly dependent on Na
+/H
+ exchange and partly on extracellular Ca
2+. In contrast, the addition of LDL produced a decrease of pHi. Under Ca
2+-free condition, pHi was further decreased by LDL. In cells pretreated with amiloride, however, pHi was not further decreased by LDL. It was found that probucol promoted cell proliferation, and LDL inhibited cell proliferation. Addition of probucol also enhanced prostacyclin generation by HUVEC. This enhancement of PGI
2 generation resulted from increased release of Ca
2+ from the storage sites, due not only to increased production of inositol 1,4,5-triphosphate (IP
3) but also to the increase of pHi. These findings may help to explain the antiatherosclerotic action of probucol.
This study was designed to evaluate the effect of thrombin on prostacyclin (PGI
2) production in cultured human vascular endothelial cells in association with intracellular Ca
2+ and with the gene ...expression of prostaglandin H
2 synthase (PGHS) and phospholipase A
2 (PLA
2) using competitive polymerase chain reaction. Thrombin enhanced the PGI
2 synthesis dependent with time. Additionally, thrombin increased the intracellular Ca
2+, which stimulates PLA
2, resulting in arachidonic acid cleavage from membrane phospholipids and its subsequent conversion into PGI
2 through the PGHS pathway. The elevation of intracellular Ca
2+ was a result of Ca
2+ influx and Ca
2+ release from its intracellular storage sites. In this study, PGHS-1 mRNA was constitutively expressed, whereas PGHS-2 mRNA was not. With the stimulation of thrombin, cytosolic PLA
2 (cPLA
2) mRNA increased 9-fold at 15 min, PGHS-1 mRNA increased 3.4-fold at 180 min, and PGHS-2 mRNA increased 38-fold at 60 min. These results suggest that the elevation of intracellular Ca
2+ and the expression of cPLA
2, PGHS-1, and PGHS-2 mRNA cause PGI
2 generation.
We investigated the effects of bradykinin (BK) on the regulatory mechanism of PGI2 synthesis in endothelial cells with reference to intracellular Ca2+ kinetics, mRNA expression of cytosolic ...phospholipase A2 (cPLA2) and prostaglandin H2 synthase-1 (PGHS-1). PGI2 generation increased with BK stimulation in a time dependent manner for 180 minutes. In the early phase of BK stimulation, intracellular Ca2+ (Ca2+i) concentration was increased by the influx of extracellular Ca2+ and a release from the Ca2+ storage site. However the increase of Ca2+ i was observed for only 2 minutes. cPLA2 mRNA expression was 87 amol/μg RNA at rest. The additon of BK produced 746amol/μg RNA at 15 minutes. After pretreatment with cycloheximide, cPLA mRNA was superinduced. PGHS-1 mRNA expression was 562 amol/μg RNA at rest. The additon ofBK produced 10608 amol/μg RNA at 180 minutes. After pretreatment with cycloheximide, PGHS-1 mRNA expression was inhibited. These results indicate that in the early phase of BK stimulation, Ca2+i activates cPLA2, and cPLA2 is considered to increase PGI2 generation. After 2 minutes, the increase of cPLA2 and PGHS-1 mRNA with BK stimulation seems to lead to an increase in these enzymes, but the time courses of these mRNA expressions were not the same. It is suggested that BK induced PGI2 generation depends not only on the increase of Ca2+i but also on the mRNA of cPLA2 and PGHS-1.
A 39-year-old man with Laurence-Moon-Bardet-Biedl syndrome (LMBB syndrome) was admitted because of severe anemia in spite of frequent blood transfusions. He had an 18-year history of NIDDM. ...Hemodialysis had been instituted one year before hospitalization because his renal function had grown worse. Gastroenoscopic examination performed after admission revealed advanced gastric cancer (Borrmann type III). The patient died of gastric cancer complicated by carcinomatous peritonitis, obstructive jaundice and DIC syndrome. Renal involvement has recently been reported in LMBB syndrome. Although the patient had a long history of NIDDM, autopsy data showed histopathological changes which included the mesangial proliferation and interstitial fibrosis previously described in LMBB syndrome, but no typical changes of diabetic nephropathy. We concluded that renal involvement in LMBB syndrome may have caused the deterioration of this patient's renal function.
In high carbon steel, TTT nose temperature rises and upper baninte becomes easy to be formed with quantity of Si addition. Generation of upper bainite is reduced by boron addition. In this study, the ...influence of boron addition on isothermal transformation behavior in Si-added high carbon steel was clarified. By boron addition, lamellar spacing and growth rate of pearlite doesn’t change, but the nucleation of pealite is reduced. But nucleation of pearlite is promoted when Fe23(C,B)6 precipitates. In the Si-added high carbon steel, upper bainite is often formed with the generated ferrite on prior austenite grain boundary. It is inferred that boron reduces ferrite generation in grain boundary which causes upper bainite formation. It is confirmed that effective existence state of boron is grain boundary segregation.
MHC class I-related protein 1 (MR1) is a metabolite-presenting molecule that restricts MR1-reactive T cells including mucosal-associated invariant T (MAIT) cells. In contrast to MAIT cells, the ...function of other MR1-restricted T cell subsets is largely unknown. Here, we report that mice in which a T cell-specific transcription factor, B-cell lymphoma/leukemia 11B (Bcl11b), was ablated in immature thymocytes (Bcl11b
mice) develop chronic inflammation. Bcl11b
mice lack conventional T cells and MAIT cells, whereas CD4
IL-18R
αβ T cells expressing skewed Traj33 (Jα33)
T cell receptors (TCR) accumulate in the periphery, which are necessary and sufficient for the pathogenesis. The disorders observed in Bcl11b
mice are ameliorated by MR1-deficiency, transfer of conventional T cells, or germ-free conditions. We further show the crystal structure of the TCR expressed by Traj33
T cells expanded in Bcl11b
mice. Overall, we establish that MR1-reactive T cells have pathogenic potential.
•Structure of thaumatin under acidic conditions (pH 4.0) was determined.•At pH 4.0, the Tm of thaumatin was substantially lower than that at pH 6.0.•Relative B-factor values illustrate the changes in ...structural features due to a pH change.•The reduction in relative flexibility might play an important role in preventing thermal aggregation.
Thaumatin is an intensely sweet-tasting protein. Its sweetness persists when heated under acidic conditions, but disappears when heated at a pH above 7.0. To clarify how the structural features of thaumatin resist insoluble aggregation during heating under acidic conditions, we analysed its crystal structure obtained at pH 4.0, 6.0, and 8.0. Simultaneously, the melting temperature (Tm) at these pH levels was determined using differential scanning fluorimetry. At pH 4.0, the Tm of thaumatin was substantially lower and the overall B-factor value of its structure was higher than those at pH 6.0. Interestingly, the relative B-factor values for most lysine residues decreased as the pH reduced. These results suggest that the overall structure at pH 4.0 becomes flexible but the relative flexibility of some regions is lower than that at pH 6.0. Thus, the reduction in relative flexibility might play an important role in preventing thermal aggregation, thereby maintaining the sweetness.
Functional areas in fMRI studies are often detected by brain-behavior correlation, calculating across-subject correlation between the behavioral index and the brain activity related to a function of ...interest. Within-subject correlation analysis is also employed in a single subject level, which utilizes cognitive fluctuations in a shorter time period by correlating the behavioral index with the brain activity across trials. In the present study, the within-subject analysis was applied to the stop-signal task, a standard task to probe response inhibition, where efficiency of response inhibition can be evaluated by the stop-signal reaction time (SSRT). Since the SSRT is estimated, by definition, not in a trial basis but from pooled trials, the correlation across runs was calculated between the SSRT and the brain activity related to response inhibition. The within-subject correlation revealed negative correlations in the anterior cingulate cortex and the cerebellum. Moreover, the dissociation pattern was observed in the within-subject analysis when earlier vs. later parts of the runs were analyzed: negative correlation was dominant in earlier runs, whereas positive correlation was dominant in later runs. Regions of interest analyses revealed that the negative correlation in the anterior cingulate cortex, but not in the cerebellum, was dominant in earlier runs, suggesting multiple mechanisms associated with inhibitory processes that fluctuate on a run-by-run basis. These results indicate that the within-subject analysis compliments the across-subject analysis by highlighting different aspects of cognitive/affective processes related to response inhibition.
This study describes the Ku -band 70- and 30-W-class internally matched gallium nitride (GaN) power amplifiers (PAs) for multi-carrier satellite communications (SatComs). The GaN PAs maintain low ...third-order intermodulation distortion (IMD3) over a wide offset frequency range of up to 400 MHz, whereas in the Ku -band, one PA can deliver a high peak output power of approximately 70 W and the other PA, a peak output power of higher than 30 W. To realize a wide offset frequency operation, our proposed output-matching circuit includes three different types of difference-frequency short circuits, two of which are embedded into a tournament-shaped output-matching circuit inside the PA package and the rest is embedded into the drain bias feed placed outside the package. To verify the short-circuit design and its effectiveness, two different power classes (70 and 30 W), Ku -band GaN PAs, were designed and fabricated, and then, their output transfer characteristics focusing on IMD3 were measured. The measurements show that the 70-W-class GaN PA achieves a peak output power of 48.6 dBm while maintaining a linear output power of over 40 dBm and an IMD3 of less than −26 dBc over wide offset frequencies ranging from 1 to 400 MHz. The 30-W-class GaN PA maintains a linear output power of over 36.3 dBm and an IMD3 of less than −27 dBc over wide offset frequencies of up to approximately 600 MHz. To the best of the authors' knowledge, these PAs have a record output power level over a wide frequency range of 1-400 MHz or higher under the condition of a low IMD3 of less than −25 dBc, compared to previously reported Ku -band GaN PAs used for multi-carrier SatComs.
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