Electron Heating in High Mach Number Collisionless Shocks.

The energy partition in high Mach number collisionless shock waves is central to a wide range of high-energy astrophysical environments. We present a new theoretical model for electron heating that accounts for the energy exchange between electrons and ions at the shock. The fundamental mechanism relies on the difference in inertia between electrons and ions, resulting in differential scattering of the particles off a decelerating magnetically dominated microturbulence across the shock transition. We show that the self-consistent interplay between the resulting ambipolar-type electric field and diffusive transport of electrons leads to efficient heating in the magnetic field produced by the Weibel instability in the high Mach number regime and is consistent with fully kinetic simulations.

An optical spectrum of the afterglow of a gamma-ray burst at a redshift of z = 6.295.

The prompt gamma-ray emission from gamma-ray bursts (GRBs) should be detectable out to distances of z > 10 (ref. 1), and should therefore provide an excellent probe of the evolution of cosmic star formation, reionization of the intergalactic medium, and the metal enrichment history of the Universe. Hitherto, the highest measured redshift for a GRB has been z = 4.50 (ref. 5). Here we report the optical spectrum of the afterglow of GRB 050904 obtained 3.4 days after the burst; the spectrum shows a clear continuum at the long-wavelength end of the spectrum with a sharp cut-off at around 9,000 A due to Lyman alpha absorption at z approximately 6.3 (with a damping wing). A system of absorption lines of heavy elements at z = 6.295 +/- 0.002 was also detected, yielding the precise measurement of the redshift. The Si ii fine-structure lines suggest a dense, metal-enriched environment around the progenitor of the GRB.

Pharmacokinetics and pharmacodynamics of vildagliptin in Japanese patients with type 2 diabetes.

OBJECTIVE: To assess the pharmacokinetics, pharmacodynamics and safety of vildagliptin, a potent and selective inhibitor of dipeptidyl peptidase IV (DPP-4), in Japanese patients with Type 2 diabetes. METHODS: In this randomized, double-blind, placebo-controlled, parallel-group study, 62 Japanese patients with Type 2 diabetes received vildagliptin 10 mg, 25 mg or 50 mg twice daily for 7 days. Blood samples were collected for the determination of plasma concentrations of vildagliptin, DPP-4, glucagon-like peptide-1 (GLP-1), glucose, insulin and glucagon. RESULTS: Exposure to vildagliptin (area under the plasma concentration-time curve from 0 to 12 h (AUC0-12h) and the maximum plasma concentration (Cmax)) increased in an approximately dose-proportional manner, and no accumulation was observed following multiple doses of vildagliptin (accumulation factor 1.00 - 1.02). DPP-4 activity was completely inhibited for varying durations by all doses of vildagliptin; the duration of complete DPP-4 inhibition was dose-dependent. DPP-4 inhibition after vildagliptin 50 mg twice daily remained > 80% throughout the 24-h period. Vildagliptin treatment led to a dose-dependent increase in plasma active GLP-1 levels; the overall increases (area under the effect-time course from 0 to 8 h, AUE0-8h) after 7 days' treatment were 1.5-, 1.7-, and 1.8-fold with vildagliptin 10 mg, 25 mg and 50 mg twice daily, respectively (all p < 0.0001 vs. placebo). Postprandial plasma glucose during the 4-h period after breakfast was significantly reduced with the 10, 25 and 50 mg vildagliptin doses by 50.3, 92.2 and 69.5 mg·h/dl, respectively. Insulin levels remained unchanged in the context of reduced glucose levels at all doses studied. CONCLUSIONS: Vildagliptin demonstrated similar pharmacokinetic and pharmacodynamic effects in Japanese patients to those observed previously in non-Japanese patients with Type 2 diabetes.

Modulation of cell-adhesive activity of fibronectin by the alternatively spliced EDA segment.

Fibronectin (FN) has a complex pattern of alternative splicing at the mRNA level. One of the alternatively spliced segments, EDA, is prominently expressed during biological processes involving substantial cell migration and proliferation, such as embryonic development, malignant transformation, and wound healing. To examine the function of the EDA segment, we overexpressed recombinant FN isoforms with or without EDA in CHO cells and compared their cell-adhesive activities using purified proteins. EDA+ FN was significantly more potent than EDA- FN in promoting cell spreading and cell migration, irrespective of the presence or absence of a second alternatively spliced segment, EDB. The cell spreading activity of EDA+ FN was not affected by antibodies recognizing the EDA segment but was abolished by antibodies against integrin alpha5 and beta1 subunits and by Gly-Arg-Gly-Asp-Ser-Pro peptide, indicating that the EDA segment enhanced the cell-adhesive activity of FN by potentiating the interaction of FN with integrin alpha5beta1. In support of this conclusion, purified integrin alpha5beta1 bound more avidly to EDA+ FN than to EDA- FN. Augmentation of integrin binding by the EDA segment was, however, observed only in the context of the intact FN molecule, since the difference in integrin-binding activity between EDA+ FN and EDA- FN was abolished after limited proteolysis with thermolysin. Consistent with this observation, binding of integrin alpha5beta1 to a recombinant FN fragment, consisting of the central cell-binding domain and the adjacent heparin-binding domain Hep2, was not affected by insertion of the EDA segment. Since the insertion of an extra type III module such as EDA into an array of repeated type III modules is expected to rotate the polypeptide up to 180 degrees at the position of the insertion, the conformation of the FN molecule may be globally altered upon insertion of the EDA segment, resulting in an increased exposure of the RGD motif in III10 module and/or local unfolding of the module. Our results suggest that alternative splicing at the EDA exon is a novel mechanism for up-regulating integrin-binding affinity of FN operating when enhanced migration and proliferation of cells are required.

Expression and properties of two types of protein kinase C: alternative splicing from a single gene.

Two complementary DNA's, encoding the complete sequences of 671 and 673 amino acids for subspecies of rat brain protein kinase C, were expressed in COS 7 cells. The complementary DNA sequence analysis predicted that the two enzymes are derived from different ways of splicing and differ from each other only in the short ranges of their carboxyl-terminal regions. Both enzymes showed typical characteristics of protein kinase C that responded to Ca2+, phospholipid, and diacylglycerol. The enzymes showed practically identical physical and kinetic properties and were indistinguishable from one of the several subspecies of protein kinase C that occurs in rat brain but not in untransfected COS 7 cells. Partial analysis of the genomic structure confirmed that these two subspecies of protein kinase C resulted indeed from alternative splicing of a single gene.

Effect of tibial component alignment on knee kinematics and ligament tension in medial unicompartmental knee arthroplasty.

OBJECTIVES: Unicompartmental knee arthroplasty (UKA) is one surgical option for treating symptomatic medial osteoarthritis. Clinical studies have shown the functional benefits of UKA; however, the optimal alignment of the tibial component is still debated. The purpose of this study was to evaluate the effects of tibial coronal and sagittal plane alignment in UKA on knee kinematics and cruciate ligament tension, using a musculoskeletal computer simulation. METHODS: The tibial component was first aligned perpendicular to the mechanical axis of the tibia, with a 7° posterior slope (basic model). Subsequently, coronal and sagittal plane alignments were changed in a simulation programme. Kinematics and cruciate ligament tensions were simulated during weight-bearing deep knee bend and gait motions. Translation was defined as the distance between the most medial and the most lateral femoral positions throughout the cycle. RESULTS: The femur was positioned more medially relative to the tibia, with increasing varus alignment of the tibial component. Medial/lateral (ML) translation was smallest in the 2° varus model. A greater posterior slope posteriorized the medial condyle and increased anterior cruciate ligament (ACL) tension. ML translation was increased in the > 7° posterior slope model and the 0° model. CONCLUSION: The current study suggests that the preferred tibial component alignment is between neutral and 2° varus in the coronal plane, and between 3° and 7° posterior slope in the sagittal plane. Varus > 4° or valgus alignment and excessive posterior slope caused excessive ML translation, which could be related to feelings of instability and could potentially have negative effects on clinical outcomes and implant durability.Cite this article: K. Sekiguchi, S. Nakamura, S. Kuriyama, K. Nishitani, H. Ito, Y. Tanaka, M. Watanabe, S. Matsuda. Bone Joint Res 2019;8:126-135. DOI: 10.1302/2046-3758.83.BJR-2018-0208.R2.

Fruit and Vegetable Consumption and Frailty: A Systematic Review.

OBJECTIVE: To identify currently available evidence on fruit and vegetable consumption in association with frailty by conducting a systematic review of the literature and to summarise and critically evaluate it. DESIGN: Systematic review. SETTING: Four electronic databases (Embase, MEDLINE, CINAHL and PsycINFO) were systematically searched in August 2017 for observational cohort studies providing cross-sectional or prospective associations between fruit and vegetable consumption and frailty risks. Additional studies were searched by manually reviewing the reference lists of the included studies and related review papers and conducting forward citation tracking of the included studies. The methodological quality of prospective studies was assessed using the Newcastle-Ottawa scale. PARTICIPANTS: Community-dwelling general populations. RESULTS: A total of 6251 studies were identified, of which five prospective studies with follow-up periods of 2-10.5 years and two cross-sectional studies were included. Among the five prospective studies, three had adequate methodological quality. Because of different measurements and statistical methodologies, a meta-analysis was not possible. The two studies of good quality showed that fruit and vegetable consumption was mostly associated with lower risk of incident frailty. The other study as a sub-analysis retrospectively examined baseline fruit and vegetable consumption of those who developed frailty and those who did not at follow-up and showed no significant associations. CONCLUSIONS: Although good quality studies on this topic are scarce, there is some suggestion that higher fruit and vegetable consumption may be associated with lower frailty risk. More high quality research is needed.

Low-temperature resistance of higher plants is significantly enhanced by a nonspecific cyanobacterial desaturase.

A broad-specificity delta 9 desaturase gene was cloned from the cyanobacterium Anacystis nidulans. The enzyme introduces a cis-double bond at the delta 9 position of both 16 and 18 carbon saturated fatty acids linked to many kinds of membrane lipids. The gene was stably introduced into tobacco plants under transcriptional control of the cauliflower mosaic virus 35S promoter, and the enzyme was targeted into plastids by the transit peptide of the pea RuBisCO small subunit. The transgenic plants had a highly reduced level of saturated fatty acid content in most membrane lipids and exhibited a significant increase in chilling resistance.

Homeobox protein Hex induces SMemb/nonmuscle myosin heavy chain-B gene expression through the cAMP-responsive element.

Recent studies have shown that the homeobox gene Hex plays an important role in inducing differentiation of vascular endothelial cells. In this study, we examined the expression of Hex in vascular smooth muscle cells (VSMCs) in vitro and in vivo. Immunohistochemistry showed a marked induction of Hex protein in neointimal VSMCs after balloon injury in rat aorta. Western and reverse transcriptase-polymerase chain reaction analyses demonstrated that Hex was abundantly expressed in cultured VSMCs, whereas it was undetectable in other cell types or in normal aorta. The expression pattern of Hex was similar to that of SMemb/NMHC-B, a nonmuscle isoform of myosin heavy chain that we have previously reported to be a molecular marker of dedifferentiated VSMCs. We next examined the role of Hex in SMemb gene transcription. Promoter analysis demonstrated that the sequence identical to consensus cAMP-responsive element (CRE) located at -481 of the SMemb promoter was critical for Hex responsiveness. Mutant Hex expression vector, which lacks the homeodomain, failed to stimulate SMemb gene transcription, suggesting the requirement of the homeodomain for its transactivation. Elecrophoretic mobility shift assay showed that Hex binds to a consensus binding sequence for homeobox proteins, but not to CRE. Cotransfection of protein kinase A expression vector increased the ability of Hex to stimulate SMemb promoter activity in a CRE-dependent manner. Overexpression of CRE binding protein (CREB), but not Mut-CREB which contains mutation at Ser133, strongly activated Hex-induced SMemb promoter activity. These results suggest that Hex mediates transcriptional induction of the SMemb/NMHC-B gene via its homeodomain, and Hex can function as a transcriptional modulator of CRE-dependent transcription in VSMCs.

Oncodevelopmental regulation of the alternative splicing of fibronectin pre-messenger RNA in human lung tissues.

Alternative splicing of fibronectin pre-mRNA at the ED-A region has been shown to be deregulated in malignant human liver tumors (F. Oyama et al., J. Biol. Chem., 264: 10331-10334, 1989). In order to extend this observation to other human cancers, we investigated the splicing patterns of fibronectin pre-mRNA at both ED-A and ED-B regions in normal, fetal, and cancerous lung tissues. Unlike in the liver, the ED-A+ mRNA was constitutively expressed in the lung irrespective of ontogenic or oncogenic stages. Although fetal tissues expressed the ED-A+ mRNA slightly more than did adult tissues, there was virtually no significant difference between malignant and nonmalignant tissues in the level of the ED-A+ mRNA. In contrast, significant expression of the ED-B+ mRNA was observed with fetal and cancerous tissues but not with normal adult tissues. Increased expression of the ED-B+ mRNA was associated with all types of lung cancer including adenocarcinoma, squamous cell carcinoma, small cell carcinoma, and large cell carcinoma. These results indicate that it is the ED-B, but not the ED-A, region where the alternative splicing of fibronectin pre-mRNA is oncodevelopmentally regulated in the lung. Our results also suggest that deregulation of the tissue-specific alternative splicing of fibronectin pre-mRNA is not a unique phenotype of liver cancer but rather a general feature of naturally occurring human cancer.

Qualitative and quantitative changes of human tenascin expression in transformed lung fibroblast and lung tumor tissues: comparison with fibronectin.

Qualitative and quantitative alterations of human tenascin (TN) expression in virally transformed lung fibroblasts and in lung tumor tissues were investigated using S1 nuclease protection analysis in comparison with those of fibronectin (FN). Transformed fibroblasts and fetal lung tissues expressed more TN mRNA with an extra sequence encoding the sixth FN type III repeat than did normal cells and adult tissues. The splicing pattern of TN mRNA was also altered in many lung cancer tissues, showing increased or sometimes decreased expression of the TN mRNA with the extra sequence when compared with their surrounding normal tissues. These results provide additional evidence for the oncodevelopmental regulation of alternative RNA splicing in human lung tissues, first observed with FN mRNA (F. Oyama, et al., Cancer Res., 50: 1075-1078, 1990). Quantitative analysis of the levels of TN and FN mRNAs showed that the ratio of TN mRNA to FN mRNA was significantly increased in transformed fibroblasts and in some lung tumor tissues, when compared with their normal counterparts. Among different types of lung tumors, a significant increase of the TN/FN ratio was observed with most squamous cell carcinoma but with only a small fraction of adenocarcinoma. Since TN has been shown to inhibit cell adhesion to FN, the altered ratio of TN mRNA to FN mRNA may well affect the adhesive and migratory properties of tumor cells in lung cancer tissues.

Coordinate oncodevelopmental modulation of alternative splicing of fibronectin pre-messenger RNA at ED-A, ED-B, and CS1 regions in human liver tumors.

The molecular diversity of fibronectin arises from alternative RNA splicing at regions termed ED-A, ED-B, and IIICS. We investigated the splicing patterns of fibronectin pre-mRNA at both ED-B and IIICS regions in various human liver tissues with an emphasis on the expression of the alternative cell adhesive site CS1 within the IIICS region. The relative abundance of the fibronectin mRNA containing the CS1 sequence was significantly increased in both fetal and cancerous liver tissues, although it was not affected in nonmalignant tissues with chronic hepatitis and cirrhosis. Similarly, the relative abundance of the fibronectin mRNA containing the ED-B region was also increased in both fetal liver and liver tumors, showing a close parallelism with the splicing pattern at the ED-A region. Immunohistochemical examination of cancerous liver tissues with monoclonal antibodies directed to the ED-A and ED-B segments revealed that the fibronectin isoforms containing these extra peptide segments were specifically deposited in the tumor nodules. Other genes encoding kininogen, gamma chain of fibrinogen, and beta-amyloid protein precursor, all of which had been shown to be alternatively processed, did not show any significant alteration in the splicing pattern in cancerous liver tissues. These results indicate that the alternative splicing of fibronectin pre-mRNA at the ED-A, ED-B, and IIICS regions is coordinately modulated in both fetal and cancerous liver tissues toward inclusion of the extra peptide segments and that not all but only selected genes are susceptible for "fine tuning" of alternative RNA splicing in cancerous liver tissues.

Detection of patients with cancer by monoclonal antibody directed to lactoneotetraosylceramide (paragloboside).

A hybridoma producing monoclonal antibody (H11) directed to lactoneotetraosylceramide (paragloboside) has been established from spleen cells of a mouse immunized with paragloboside. The monoclonal antibody H11 (immunoglobulin M type) was selected from five clones showing different reactivities with paragloboside. The monoclonal antibody was highly specific to paragloboside and lacked reactivity with other glycolipids including glucosylceramide, lactosylceramide, globotriaosylceramide, globotetraosylceramide, gangliotriaosylceramide, gangliotetraosylceramide, and GalNAc beta 1-4[NeuAc alpha 2-3]Gal beta 1-4Glc beta 1-1Cer. However, the monoclonal antibody (H11) was found to bind to lactosamine-containing glycolipids at their terminals, such as i- and I-type glycolipids as well as paragloboside. A two-step sandwich radioimmunoassay method for paragloboside antigen in serum was established by using the monoclonal antibody. The mean paragloboside antigen concentration in the sera from 20 normal individuals was 25.3 ng/ml. If the cutoff value was set at 80.9 ng/ml [25.3 + 2 x 27.8 (SD)], only 1 of 20 healthy controls had an elevated paragloboside value in the serum, whereas sera from 9 of 12 (75.0%) hepatoma, 4 of 10 (40%) pancreatic cancer, 16 of 40 (40.0%) stomach cancer, and 6 of 10 (60%) lung cancer patients had elevated paragloboside values. Sera from 3 of 8 hepatitis patients and 7 of 10 liver cirrhosis patients were estimated to be positive but sera from 16 patients with benign disease had paragloboside levels lower than the cutoff value. A larger amount of the antigen was found in liver metastases from colorectal carcinoma compared to the normal counterpart. The antigen was also detected in the medium of various human cancer cells and meconium. However, the antigen in the sera, medium, meconium, and cancer tissue seemed to be associated with glycoprotein or lipoprotein, because most of the antigen activity was eluted in the void volume fraction on high-performance liquid chromatography with a gel filtration column.

Suppression of transformed phenotypes of human fibrosarcoma cells by overexpression of recombinant fibronectin.

Loss of fibronectin (FN) from the cell surface has been shown to be closely associated with malignant transformation of cells. To elucidate the role of the FN matrix in the modulation of malignant phenotypes, we overexpressed a full-length cDNA encoding plasma-type FN in HT1080 human fibrosarcoma cells. The cells overexpressing FN adopted a more flattened morphology and deposited a moderately developed FN matrix both in vitro and in vivo, although the level of expression of integrin alpha5beta1 remained unchanged. FN-overexpressing cells exhibited a reduced cell motility on the substratum and grew poorly when injected s.c. into nude mice. Overexpression of FN also suppressed the ability of the tumor cells to proliferate in soft agar, whereas the suppression was reversed by inclusion in soft agar of the Arg-Gly-Asp (RGD)-containing peptide and adhesion-blocking antibodies against the central cell-binding domain of FN. Neither cell motility nor growth potential was altered by overexpression of a truncated form of FN lacking the central cell-binding domain. These results, taken together, indicate that increased deposition of FN in the pericellular matrix per se can suppress the motility and growth potential of tumor cells through interaction with RGD-recognizing integrins, most likely alpha5beta1.

Accumulation of gangliosides with N-acetylneuraminosyl(alpha 2-6)lactosamine structure in primary human hepatoma.

Gangliosides of hepatomas have been analyzed by using a monoclonal antibody directed to N-acetylneuraminosyl(alpha 2-6)lactoneotetraosylceramide (sialyl(alpha 2-6)paragloboside), which was prepared by injecting the monosialoganglioside fraction of human meconium into BALB/c mice. The monoclonal antibody, named MSG-15, was found to bind sialyl(alpha 2-6)paragloboside, but it failed to react with other gangliosides, including N-acetylneuraminosyl(alpha 2-3)lactoneotetraosylceramide (sialyl (alpha 2-3)paragloboside) and "Ii"-type gangliosides. MSG-15 was found to recognize NeuAc alpha 2-6Gal beta structure of the ganglioside. Gangliosides obtained from human hepatomas were analyzed by immunostaining on high-performance thin-layer chromatography plates using the monoclonal antibody MSG-15. All primary hepatoma samples used in this study (nine samples) were found to contain sialyl(alpha 2-6)paragloboside, which accounted for 13-31% of the monosialoganglioside fractions in the hepatomas. Furthermore, MSG-15 recognized several monosialogangliosides in addition to sialyl(alpha 2-6)paragloboside. These gangliosides apparently also contain a terminal NeuAc alpha 2-6Gal beta structure. Other ganglioside fractions obtained from hepatoma and meconium were immunostained on thin layer chromatography plates with MSG-15. Additionally, another monoclonal antibody (H-11), which recognizes terminal lactosamine structure, was used to immunostain these fractions after sialidase treatment. Bands stained with both monoclonal antibodies showed similar mobilities to each other in the di- and trisialoganglioside fractions as well as monosialoganglioside fraction. In control liver, GM3 ganglioside accounted for 92% of monosialoganglioside fraction, and sialyl(alpha 2-6)paragloboside accounted for less than 1% of the fraction. Immunohistochemical study by using MSG-15 in tissue sections from hepatocellular carcinoma and normal liver tissues demonstrated that only hepatocellular carcinoma cells gave a positive reaction. These results suggest that the biosynthetic pathway of gangliosides containing NeuAc alpha 2-6Gal beta 1-4GlcNAc beta structure is activated in hepatoma cells.

Decreased fibronectin expression in Met/HGF-mediated tumorigenesis.

The tyrosine kinase receptor Met and its ligand, hepatocyte growth factor (HGF)/scatter factor are involved in the etiology and progression of a number of human cancers. Coexpression of Met and HGF in mesenchymal cells increases the tumorigenic and metastatic potential of the cells. In the studies described here, we used differential display screening to identify changes in gene expression that are initiated by Met/HGF, and that may lead to these phenotypes. We learned that Met/HGF signaling resulted in greatly decreased fibronectin mRNA production in three different human and mouse tumor cell lines; these decreases in fibronectin mRNA were paralleled by decreases in fibronectin protein. We also found a progressive decrease in fibronectin in tumor explants and metastases derived from the Met/HGF transformed cells. The absence of fibronectin expression is a frequent cancer phenotype; our results indicate that decreases in fibronectin correlate with, but are not essential for, MetHGF/SF-mediated tumorigenesis.

Virus-induced fusion of human erythrocyte ghosts. I. Effects of macromolecules on the final stages of the fusion reaction.

Human erythrocyte ghosts prepared by hypotonic hemolysis can be fused by Sendai virus, provided that certain macromolecules (bovine serum albumin, dextran and others) are sequestered in the ghosts. Since fusion of the ghosts is dependent on intactness of the F(fusion)-glycoprotein of the virion, and since the other requirements for this reaction are also similar to those for the Sendai virus-induced fusion of intact erythrocytes, this system can be used as a model for the Sendai virus-induced cell fusion reaction. Sequestered macromolecules seem to be required for rounding of locally fused ghosts. Under low osmotic swelling conditions, such as use of ghosts sealed without macromolecules or using bovine serum albumin-loaded ghosts sealed in the presence of external macromolecules, no apparently complete cell fusion (large spherical polyghost formation) could be observed. Even under these conditions, however, occurrence of local cell fusion could be demonstrated either by transfer of fluorescent-labeled albumin from one ghost to an other, or by observation of polyghost formation after osmotic swelling in the cold. Thus, final stages of the fusion reaction can be divided into local cell-cell fusion which could not be observed by phase-contrast microscopy, and rounding (i.e. formation of spherical polyghosts). For the observation of fusion of ghosts, the last step seems to be important.

Significance of circulating hepatocyte growth factor level as a prognostic indicator in primary breast cancer.

The circulating hepatocyte growth factor (HGF)/scatter factor level is frequently increased in advanced cancer patients. In this study, we have assessed the prognostic value of the circulating HGF level determined by enzymatic immunoassay in primary breast cancer patients. Of 200 primary breast cancer patients, 54 (27.0%) showed the increase of serum HGF level according to the age-matched cutoff values. The prognosis of the patients with the increased HGF level was statistically worse than that of the patients with normal HGF level (P = 0.0001, log-rank test). Multivariate analysis confirmed that the increase in HGF level was an independent prognostic indicator in primary breast cancer patients. In the background analysis, the increase in serum HGF level was significantly associated with tumor size, nodal status, and histological evidence of venous invasion. The data indicate that up-regulation of the circulating HGF level may predict systemic tumor spread and early relapse in primary breast cancer patients.