136 research outputs found
Single-pole nature of Lambda (1405) and structure of K-pp
We have studied the structure of K- pp by solving this system in a
variational treatment, starting from ansatz that Lambda(1405) is a K-p
quasi-bound state, Lambda* with mass 1405 MeV/c2. The structure of K-pp reveals
a molecular feature, namely, the K- in an "atomic center", Lambda*, plays a key
role in producing strong covalent bonding with the other proton. Deeply bound
Kbar nuclear systems are formed by this "super-strong" nuclear force due to
migrating real bosons, Kbar, a la Heitler-London-Heisenberg, which
overcompensates the stiff nuclear incompressibility. Theoretical background of
the Lambda (1405) ansatz is discussed in connection with the double-pole
picture of Lambda (1405) based on chiral SU(3) dynamics. Detailed analysis
reveals single-pole nature of the observable Lambda (1405). There are two kinds
of Sigma pi invariant masses experimentally observable, the usual T22 invariant
mass and the conversion T21 invariant mass. It is of vital importance to
determine whether the Lambda* mass is 1405 MeV or 1420 MeV. The T21 invariant
mass from K- absorption at rest in deuteron can provide decisive information
about this Lambda* mass problem.Comment: 8 pages, 4 figures, Proc. Hyp-
Association of serum osteoprotegerin with vascular calcification in patients with type 2 diabetes
A bone substitute with high affinity for vitamin D-binding protein―relationship with niche of osteoclasts
The biological activity of osteoblasts and osteoclasts is regulated not only by hormones but also by local growth factors, which are expressed in neighbouring cells or included in bone matrix. Previously, we developed hydroxyapatite (HA) composed of rod-shaped particles using applied hydrothermal methods (HHA), and it revealed mild biodegradability and potent osteoclast homing activity. Here, we compared serum proteins adsorbed to HHA with those adsorbed to conventional HA composed of globular-shaped particles (CHA). The two ceramics adsorbed serum albumin and γ-globulin to similar extents, but affinity for γ-globulin was much greater than that to serum albumin. The chemotactic activity for macrophages of serum proteins adsorbed to HHA was significantly higher than that of serum proteins adsorbed to CHA. Quantitative proteomic analysis of adsorbed serum proteins revealed preferential binding of vitamin D-binding protein (DBP) and complements C3 and C4B with HHA. When implanted with the femur of 8-week-old rats, HHA contained significantly larger amount of DBP than CHA. The biological activity of DBP was analysed and it was found that the chemotactic activity for macrophages was weak. However, DBP-macrophage activating factor, which is generated by the digestion of sugar chains of DBP, stimulated osteoclastogenesis. These results confirm that the microstructure of hydroxyapatite largely affects the affinity for serum proteins, and suggest that DBP preferentially adsorbed to HA composed of rod-shaped particles influences its potent osteoclast homing activity and local bone metabolism
Osteoconductivity of hydrothermally synthesized beta-tricalcium phosphate composed of rod-shaped particles under mechanical unloading
Spherical beta-tricalcium phosphate (β-TCP) granules synthesized using a unique dropping slurry method expressed good osteoconductivity with prominent bone apposition and bioresorbability when implanted into the rat femur (Gonda et al, Key Eng. Mater. 361-363:1013-1016, 2008). The spherical β-TCP granules were implanted into the bone defect created in the distal end of the right femur of each 8-week-old female Wistar rat. To analyze performance of the spherical β-TCP granules as bone substitute in the bone with reduction in osteogenic potential, the right sciatic neurectomy was performed after implantation and the right hind limb was kept unloaded for 2 weeks before euthanization. Four weeks after implantation, some spherical β-TCP granules with resorption in part were surrounded by newly formed bone. Eight and 12 weeks after implantation, most of the residual β-TCP granules were embedded in newly formed bone, and total volume of the implant and newly formed bone was more than the other portions of the bone or the bone of control animals. Osteoclast activity in the implanted area was also higher than the other portions of the bone or the bone of control animals. Replacement of the intraosseous residual β-TCP granules for bone progressed at 12 weeks after implantation compared to those at 8 weeks after implantation. These data suggested that the spherical β-TCP granules stimulated osteogenesis and osteoclast activity of the unloaded bone
Cold activation of serum complement in patients with chronic hepatitis C: study on activating pathway and involvement of IgG.
It has been documented that the serum complement activities measured by hemolytic assay (CH50) are decreased after storage of sera at a low temperature in some patients with chronic hepatitis C. However, the mechanism of this phenomenon has not been identified yet. Here, we tried to elucidate factors involved in the cold activation of complement (CAC). To clarify what pathway is activated in CAC, we measured complement cleavage products after cold storage of sera. C4d increased significantly after 12 h-storage at cold temperatures in 5 CAC (+) sera compared with 5 CAC (-) (P < 0.01) and 3 control sera (P < 0.05), while Bb did not increase in any of the groups. In order to determine whether IgG or IgG complex is necessary for CAC, 8 CAC (+) sera were incubated with Protein G Sepharose gel beads, and all of them retained hemolytic activities to some extent after cold storage. Column chromatography through Superose 6HR of CAC-positive serum identified the fractions containing molecules that induced CAC in normal serum, which were depleted by treatment with protein G Sepharose. In conclusion, CAC in hepatitis C seems to occur via a classical or lectin pathway, and the IgG complex produced in hepatitis C virus infection may be an important factor in inducing CAC, a common extrahepatic manifestation of hepatitis C.</p
Decadal–centennial-scale solar-linked climate variations and millennial-scale internal oscillations during the Early Cretaceous
Understanding climate variability and stability under extremely warm ‘greenhouse’ conditions in the past is essential for future climate predictions. However, information on millennial-scale (and shorter) climate variability during such periods is scarce, owing to a lack of suitable high-resolution, deep-time archives. Here we present a continuous record of decadal- to orbital-scale continental climate variability from annually laminated lacustrine deposits formed during the late Early Cretaceous (123–120 Ma: late Barremian–early Aptian) in southeastern Mongolia. Inter-annual changes in lake algal productivity for a 1091-year interval reveal a pronounced solar influence on decadal- to centennial-scale climatic variations (including the ~ 11-year Schwabe cycle). Decadally-resolved Ca/Ti ratios (proxy for evaporation/precipitation changes) for a ~ 355-kyr long interval further indicate millennial-scale (~ 1000–2000-yr) extreme drought events in inner-continental areas of mid-latitude palaeo-Asia during the Cretaceous. Millennial-scale oscillations in Ca/Ti ratio show distinct amplitude modulation (AM) induced by the precession, obliquity and short eccentricity cycles. Similar millennial-scale AM by Milankovitch cycle band was also previously observed in the abrupt climatic oscillations (known as Dansgaard–Oeschger events) in the ‘intermediate glacial’ state of the late Pleistocene, and in their potential analogues in the Jurassic ‘greenhouse’. Our findings indicate that external solar activity forcing was effective on decadal–centennial timescales, whilst the millennial-scale variations were likely amplified by internal process such as changes in deep-water formation strength, even during the Cretaceous ‘greenhouse’ period
Verification of the Addiction Severity Index Japanese Version (ASI-J) as a Treatment-Customization, Prediction, and Comparison Tool for Alcohol-Dependent Individuals
Objective: To demonstrate the usefulness of the Addiction Severity Index Japanese Version (ASI-J) in Japanese alcohol-dependent individuals. The ASI is a frequently used clinical and research instrument that measures severities in seven functional domains in people with substance abuse disorders. Methods: A total of 370 male inpatients with a history of alcohol dependence participated in the study. Forty-nine participants were excluded in the final analysis due to lack of reliability (i.e., patient misrepresentation or inability to understand). We used the ASI-J and a series of indexes that determined patient states during and post-treatment. Results: The correlations between ASI Composite Scores (CSs), which were calculated through a weighted formula and indicated the severity of each problem area, were significant but low in eight relations and not significant in 13 relations, indicating substantial independence of the problem areas. Significant differences were found in Family/Social CSs between abstinent and relapsed alcohol-dependent individuals. The questions of undesirable attitude were significantly related to the CSs of Employment, Drug use, Family/Social, and Psychiatric sections. Significant differences were observed in patient demographics, CS, and ASI Severity Rating (SR) and interviewer’s subjective scoring between alcohol-dependent individuals and drug abusers. CSs in Japanese alcohol-dependent individuals were generally similar to corresponding CSs in individuals from other countries, with the exception of The Netherlands. Conclusions: This study demonstrated that the ASI-J is useful for understanding individual profiles of problems for each patient and planning customized treatment. The ASI-J served as a predictive tool for relapse and compliance to treatment afterward and was shown to be useful as a comparison tool in clarifying similarities and differences between substance abuser groups
Stimulatory effect of hydrothermally synthesized biodegradable hydroxyapatite granules on osteogenesis and direct association with osteoclasts.
Calcium-deficient hydroxyapatite (HA) granules with a unique spherical shape were prepared using an applied hydrothermal method. Spherical stoichiometric HA granules were also prepared by normal sintering and both granules were used for implantation into rat tibiae to compare the biological responses to each implant. Twelve and 24 weeks after implantation, the volume of calcium-deficient HA granules was significantly less than that of stoichiometric HA granules, and the biodegradability of calcium-deficient HA granules was confirmed. The larger number of osteoclasts, larger osteoblast surface and larger bone volume in the implanted area of calcium-deficient HA than those of stoichiometric HA suggested that osteoclastic resorption of calcium-deficient HA affected osteogenesis in that area. To analyze the direct contribution of osteoclasts to osteogenesis, C2C12 multipotent myoblastic cells, which have the potential to differentiate into osteoblasts in the presence of bone morphogenetic protein 2, were cultured with supernatants of osteoclasts cultured on calcium-deficient HA, stoichiometric HA, beta-tricalcium phosphate disks or plastic dishes, or bone marrow macrophages cultured on plastic dishes. Supernatants of osteoclasts but not bone marrow macrophages stimulated the expression of Runx2 and osteocalcin in C2C12 cells in concert with bone morphogenetic protein 2. The expression of alkaline phosphatase was stimulated with supernatants of osteoclasts cultured on ceramic disks. These results suggested that osteoclasts produced certain soluble factors which stimulated osteoblastic differentiation and they were thought to be associated with the induction of a larger osteoblast surface and bone volume in the animals implanted with calcium-deficient HA granules
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