397 research outputs found
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Gingivitis and periodontitis are chronic inflammatory diseases that can lead to tooth loss. One of the causes of these diseases is the Gram-negative Porphyromonas gingivalis. This periodontal pathogen is dependent on two fimbriae, FimA and Mfa1, for binding to dental biofilm, salivary proteins, and host cells. These fimbriae are composed of five proteins each, but the fimbriae assembly mechanism and ligands are unknown. Here we reveal the crystal structure of the precursor form of Mfa4, one of the accessory proteins of the Mfa1 fimbria. Mfa4 consists of two β-sandwich domains and the first part of the structure forms two well-defined β-strands that run over both domains. This N-terminal region is cleaved by gingipains, a family of proteolytic enzymes that encompass arginine- and lysine-specific proteases. Cleavage of the N-terminal region generates the mature form of the protein. Our structural data allow us to propose that the new N-terminus of the mature protein may function as a donor strand in the polymerization of P. gingivalis fimbriae
Gauge invariance of color confinement due to the dual Meissner effect caused by Abelian monopoles
The mechanism of non-Abelian color confinement is studied in SU(2) lattice
gauge theory in terms of the Abelian fields and monopoles extracted from
non-Abelian link variables without adopting gauge fixing.
Firstly, the static quark-antiquark potential and force are computed with the
Abelian and monopole Polyakov loop correlators, and the resulting string
tensions are found to be identical to the non-Abelian string tension. These
potentials also show the scaling behavior with respect to the change of lattice
spacing.
Secondly, the profile of the color-electric field between a quark and an
antiquark is investigated with the Abelian and monopole Wilson loops. The
color-electric field is squeezed into a flux tube due to monopole supercurrent
with the same Abelian color direction. The parameters corresponding to the
penetration and coherence lengths show the scaling behavior, and the ratio of
these lengths, i.e, the Ginzburg-Landau parameter, indicates that the vacuum
type is near the border of the type1 and type2 (dual) superconductor.
These results are summarized that the Abelian fundamental charge defined in
an arbitrary color direction is confined inside a hadronic state by the dual
Meissner effect. As the color-neutral state in any Abelian color direction
corresponds to the physical color-singlet state, this effect explains
non-Abelian color confinement and supports the existence of a gauge-invariant
mechanism of color confinement due to the dual Meissner effect caused by
Abelian monopoles.Comment: 11 pages, 14 figure
Autologous fibrin-coated small-caliber vascular prostheses improve antithrombogenicity by reducing immunologic response
ObjectiveWe have recently developed a thrombin-free fibrin-coated vascular prosthesis that has a high performance rate in producing graft antithrombogenicity. We hypothesized that autologous, compared with xenologous, fibrin coatings could improve the antithrombogenicity of grafts by reducing immunologic response.MethodsAutologous fibrin-coated vascular prostheses and/or xenologous fibrin-coated vascular prostheses (internal diameter, 2 mm; length, 2.5 cm) were implanted in the bilateral carotid arteries of 50 Japanese white rabbits. They were classified into 2 groups by the selection of grafts in the individual: group I (autologous fibrin-coated vascular prosthesis and xenologous fibrin-coated vascular prosthesis); and group II (group IIa: both autologous fibrin-coated vascular prostheses, or group IIx: both xenologous fibrin-coated vascular prostheses). During a maximum of 180 days after implantation, we evaluated the thrombotic, inflammatory, and immunologic responses associated with both types of graft.ResultsAll grafts were patent at each end point. In group I, both platelet deposition and anti-graft antibodies in autologous fibrin-coated vascular prostheses were significantly less than those in xenologous fibrin-coated vascular prostheses until postoperative day 30. At postoperative day 10, there were significantly fewer CD45-positive infiltrating cells in autologous fibrin-coated vascular prostheses, and intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and nuclear factor-kappa B expression in autologous fibrin-coated vascular prostheses were less than those in xenologous fibrin-coated vascular prostheses. The neointimal hyperplasia in autologous fibrin-coated vascular prostheses was significantly decreased at postoperative day 180. In group II, serial changes of serum levels of immunoglobulin M, immunoglobulin G, interleukin-1β, and tissue-type plasminogen activator/plasminogen activator inhibitor-1 ratio in autologous fibrin-coated vascular prostheses were significantly less than those in xenologous fibrin-coated vascular prostheses. In both grafts, platelet deposition significantly correlated with serum immunoglobulin G level and tissue-type plasminogen activator/plasminogen activator inhibitor-1 ratio.ConclusionThese findings suggest that autologous fibrin coating in thrombin-free fibrin-coated vascular prostheses improve antithrombogenicity by reducing immunologic response and have a potential for clinical use in hybrid small-caliber vascular grafts
Different membrane targeting of prostaglandin EP3 receptor isoforms dependent on their carboxy-terminal tail structures
AbstractMouse prostaglandin EP3 receptor consists of three isoforms, EP3α, β and γ, with different carboxy-terminal tails. To assess the role of their carboxy-terminal tails in membrane targeting, we examined subcellular localization of myc-tagged EP3 isoforms expressed in MDCK cells. Two isoforms, EP3α and EP3β, were localized in the intracellular compartment but not in the plasma membrane, while the EP3γ isoform was found in the lateral plasma membrane and in part in the intracellular compartment. Mutant EP3 receptor lacking the carboxy-terminal tail was localized in the intracellular compartment but not in the plasma membrane. Thus, EP3 isoforms differ in subcellular targeting, and the carboxy-terminal tails play an important role in determination of the membrane targeting of EP3 receptor
Effect of Oxygen Impurities on Positronium Formation in Voids of Vanadium
To clarify the effect of oxygen impurities on positronium (Ps) formed in irradiation-induced voids, measurements of the angular correlation of two photon annihilation radiation (ACAR) have been done on vanadium samples doped with oxygen impurities and subsequently irradiated with fast neutrons of doses up to 5.5x10^cm^ at about 400℃ in the Japan Materials Testing Reactor (JMTR). It has been shown that slight contamination of voids with oxygen impurity atoms, presumably submonolayer adsorption on the void surface, causes Ps formation. On the other hand, the considerable contamination leads suppression of Ps formation. Energy loss process of Ps in voids is found to be also influenced by the surface contamination
Association between gefitinib and hemorrhagic cystitis and severely contracted bladder: a case report
<p>Abstract</p> <p>Background</p> <p>Gefitinib remains an excellent treatment option for patients with a variety of cancers, including non small cell lung cancer (NSCLC). However, clinicians must be aware of the potential of gefitinib to cause an inflammatory reaction in the skin, lungs and bladder.</p> <p>Case Presentation</p> <p>We present a case on hemorrhagic cystitis and severaly contracted bladder in a patient with NSCLC on gefitinib.</p> <p>Conclusions</p> <p>Further studies are needed to substantiate the association of gefitinib therapy with hemorrhagic cystitis and contracted bladder.</p
Non-uniform distribution of the contraction/extension (C–E) in the left ventricular myocardium related to the myocardial function
AbstractObjectiveWe attempted to disclose the microscopic characteristics of the non-uniform distribution of the contraction and extension (C–E) of the left ventricular (LV) myocardium using a new methodology (echo-dynamography).MethodsThe distributions of the “axial strain rate” (aSR) and the intra-mural velocity in the local areas of the free wall including the posterior wall (PW) and interventricular septum (IVS) were microscopically obtained using echo-dynamography with a high accuracy of 821μm in the spatial resolution. The results were shown by the color M-mode echocardiogram or curvilinear graph. Subjects were 10 presumably normal volunteers.Results(1)Both the C–E in the pulsating LV wall showed non-uniformity spatially and time-sequentially.(2)The C–E property was better evaluated by the aSR distribution method rather than the intra-mural velocity distribution method.(3)Two types of non-uniformity of the aSR distribution were observed: i.e. (i) the difference of its (+)SR (contraction: C) or (−)SR (extension: E) was solely the “magnitude”; (ii) the coexistence of both the (+) SR and (−)SR at the same time.(4)The aSR distribution during systole was either “spotted,” or “multi-layered,” or “toned” distribution, whereas “stratified,” “toned,” or “alternating” distributions were observed during diastole.(5)The aSR distribution in the longitudinal section plane was varied in the individual areas of the wall even during the same timing.(6)To the mechanical function of the LV, there was a different behavior between the IVS and PW.ConclusionsThe aSR and its distribution were the major determinants of the C–E property of the LV myocardium. Spatial as well as time-sequential uniformity of either contraction or extension did not exist. The myocardial function changed depending on the assemblage of the aSR distribution, and by the synergistic effect of (+)SR and (−)SR, the non-uniformity itself potentially served to hold the smooth LV mechanical function
Trends of correlations between serum levels of growth hormone and insulin-like growth factor-I in general practice
Serum levels of growth hormone (GH) and insulin-like growth factor (IGF)-I are crucial in the diagnosis and management of GH-related diseases. However, these levels are affected by nutritional and metabolic status. To elucidate the correlations between GH and IGF-I in various conditions, a retrospective analysis was performed for adult patients in which GH levels were examined by general practitioners during the period from January 2019 to December 2021. Of 642 patients, 33 patients were diagnosed with acromegaly, 21 were diagnosed with GH deficiency (GHD), and 588 were diagnosed with non-GH-related diseases (NGRD). In contrast to the positive correlations found between the levels of GH and IGF-I in patients with acromegaly (R=0.50; P<0.001) and patients with GHD (R=0.39; P=0.08), a negative correlation was found in the NGRD group (R=-0.23; P<0.001). In that group, the results of multivariable analysis showed that GH levels were predominantly influenced by gender and body mass index (BMI), whereas IGF-I levels were modulated by albumin in addition to age and GH. Of note, in the NGRD group, there was an enhanced negative correlation between GH and IGF-I under conditions of BMI < 22 and albumin < 4.0 g/dL (R=-0.45; P<0.001), and the negative correlation between GH and IGF-I was reinforced by excluding patients with other pituitary diseases and patients taking oral steroids (R=-0.51; P<0.001 and R=-0.59; P<0.001, respectively). Collectively, the results indicate that attention should be given to the presence of a negative correlation between serum levels of GH and IGF-I, especially in lean and low-nutritious conditions
Disorder-Enhanced Dimensionless Thermoelectric Figure of Merit zT of Non-stoichiometric Organic Conductor (TTT)2I3+δ (δ ≤ 0.1)
Sample dependence of dimensionless thermoelectric figure of merit (zT) and power factor (PF) were determined for the non-stoichiometric organic conductor (TTT)2I3+δ (TTT = tetrathiatetracene, δ ≤ 0.1) with the simultaneous measurement of the electrical resistivity (ρ), thermopower (S) and thermal conductivity on small single crystals. Both the zT and PF show large sample dependence between 10 and 310 K, even though all the samples have nearly stoichiometric composition of TTT : I3- ~ 2 : 1 (δ ∼ 0). It was found that both the electrical conductivity (σ = 1/ρ) and S increase at room temperature as disorder — that is phase mismatch among the iodine chains — becomes more pronounced. This behavior contrasts the usual tendency that the S decreases as the σ increases in conventional conductors; and suggests a new strategy to improve the zT and PF by introducing an appropriate type of disorder
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