Collagen maturity,glycation induced-pentosidine,and mineralization are increased following 3-year treatment with incadronate in dogs

Collagen cross-linking is a determinant of bone quality. A three-year treatment of bisphosphonate-incadronate disodium-in beagles increased degree of mineralization, collagen maturity, and pentosidine, a compound with advanced glycation end products. The treatment had no effect on the total amount of enzymatic cross-link formation. INTRODUCTION: Collagen cross-linking is a determinant of bone quality. Recently, we reported that long-term treatment with bisphosphonate increased microdamage accumulation. The aim of this study was to clarify the effect of a three-year treatment with bisphosphonate on degree of mineralization and immature and mature enzymatic cross-links and non-enzymatic collagen cross-link, pentosidine, in cortical bone in the same dogs. METHODS: Twenty-nine 1-year-old beagles (15 males, 14 females) were divided into three groups that daily were given vehicle or incadronate at doses of 0.3 or 0.6 mg/kg/day orally for three years. A cortex of a rib was fractionated into low- and high-density portions. The contents of calcium, phosphorus, enzymatic immature and mature cross-links, and the non-enzymatic glycation product pentosidine were determined in each fraction. RESULTS: Calcium, phosphorus, and pentosidine contents and the ratio of mature to immature cross-links increased significantly with incadronate in a dose-dependent manner, but the total amount of enzymatic cross-links was unchanged. The pentosidine content correlated inversely with cortical activation frequency (p < 0.01). CONCLUSION: Long-term suppression of bone remodeling by bisphosphonate increases degree of mineralization, collagen maturity, and non-enzymatic cross-linking.     

Augmented antiproliferative effect of tumor necrosis factor (TNF), lymphotoxin and glycyrrhizin in combined use with diethyldithiocarbamate on Meth A tumor cells in vitro

Role of oxygen free radicals in inhibition of proliferation of Meth A tumor cells was studied. Diethyldithiocarbamate (DDC), a chelator which inactivates superoxide dismutase, was used to examine the effect of tumor necrosis factor (TNF), lymphotoxin preparation derived from a human lymphoid cell line (c-LT) and glycyrrhizin (GL) on in vitro proliferation of Meth A tumor cells. High degree of antiproliferative effect was observed when DDC was added simultaneously with TNF to target cells. Similar effect was obtained by the addition of GL. However, augmentation of antiproliferative effect was not observed when c-LT was added. However, augmentation of antiproliferative effect was observed when the target cells had been treated with DDC in advance of the addition of TNF, GL or c-LT. Roles of oxygen free radicals in inhibition of tumor cell proliferation were discussed.     

Interference of a ventricular assist device with magnetic navigation during insertion of Sherlock 3CG™, a bedside peripherally inserted central catheter

Journal of Artificial Organs - Recently, the Sherlock 3CG™ Tip Confirmation System, including a magnetic tracking system and an intracavitary electrocardiography guidance system, has been...     

Human CD200 suppresses macrophage-mediated xenogeneic cytotoxicity and phagocytosis

Purpose

Various strategies, such as the generation of alpha-1,3-galactosyltransferase knocked-out pigs and CD55 transgenic pigs, have been investigated to inhibit pig to human xenogeneic rejection. Our aim is to develop strategies to overcome the hurdle of not only hyper acute rejection, but also that of cellular xenogeneic rejection (CXR). Although macrophages have been well known to play a critical role in CXR, monocyte/macrophage-mediated xenogeneic rejection has not been well studied. In this study, we evaluated the effect of CD200 in xenogeneic rejection by macrophages.

Methods

Naïve swine endothelial cells (SEC) and SEC/CD200 were co-cultured with M0 macrophages and the cytotoxicity was measured by a WST-8 assay. The phagocytosis of SEC and SEC/CD200 by macrophages was analyzed by flow cytometry.

Results

While CD200 failed to suppress a significant amount of cytotoxicity against SEC by monocytes, M0 macrophage-mediated cytotoxicity was significantly suppressed by human CD200. The phagocytosis by M0 macrophages was also tested. The phagocytosis assay revealed that human CD200 suppresses M0 macrophage-mediated phagocytosis.

Conclusions

Our findings indicate that human CD200 suppresses the xenogeneic rejection by CD200R⁺ macrophages and that the generation of hCD200 transgenic pigs for use in xenografts is very attractive for preventing the macrophage-mediated rejection.

     

Effects of Breeding Environments on Generation and Activation of Autoreactive B-1 Cells in Anti-red Blood Cell Autoantibody Transgenic Mice

In anti-red blood cell autoantibody transgenic (autoAb Tg) mice almost all B cells are deleted except for B-1 cells in the peritoneal cavity and the gut. About one-half of the auto Ab Tg mice suffer from autoimmune hemolytic anemia (AIHA) in the conventional condition. Oral administration of lipopolysaccharides activates B-1 cells and induces autoimmune symptoms in the Tg mice, suggesting that the autoimmune disease in anti-RBC autoAb Tg mice is triggered by infections. To examine the association of bacterial infections with the generation of B-1 cells and the occurrence of the autoimmune disease, we analyzed anti-RBC autoAb Tg mice bred in germ-free and specific pathogen-free conditions. In germ-free conditions, few peritoneal B-1 cells were detected, while a significant number of peritoneal B-1 cells existed in specific pathogen-free conditions. In both conditions, no mice suffered from AIHA. However, when these Tg mice were transferred to the conventional condition or injected with lipopolysaccharide, peritoneal B-1 cells expanded and some of these mice suffered from AIHA. These results clearly showed that bacterial infections are responsible for both the expansion of B-1 cells and the onset of the autoimmune disease in these Tg mice.     

Effects of immunostimulants on the in vitro generation of cytotoxic lymphocytes against cervical cancer cell lines

Human peripheral blood lymphocytes were sensitized in vitro against cervical cancer cell lines and the effect of immunostimulants, such as BCG, streptococcal preparation (OK-432), yeast cell wall, and Concanavalin A, on the generation of cytotoxic lymphocytes was examined. The cytotoxic activity of sensitized lymphocytes was augmented by the addition of OK-432 (0.01 KE/ml) during in vitro sensitization, but the induction of sensitized lymphocytes was inhibited by the addition of yeast cell wall (10 micrograms/ml). When the lymphocytes from cervical cancer patients free from tumor after surgical operation were stimulated on the autologous tumor cell monolayer, the cytotoxic lymphocytes could be generated. In vitro primed lymphocytes could be reactivated following the stimulation with OK-432 (0.01 KE/ml) for 48 hr and the requirement for a proliferative trigger seems to be important for the in vitro generation of cytotoxic lymphocytes. The role of nonspecific stimulation by LD-like products in the in vitro generation of cytotoxic lymphocytes was discussed.     

Unmutated immunoglobulin M can protect mice from death by influenza virus infection

To elucidate the role of class switch recombination (CSR) and somatic hypermutation (SHM) in virus infection, we have investigated the influence of the primary and secondary infections of influenza virus on mice deficient of activation-induced cytidine deaminase (AID), which is absolutely required for CSR and SHM. In the primary infection, AID deficiency caused no significant difference in mortality but did cause difference in morbidity. In the secondary infection with a lethal dose of influenza virus, both AID-/- and AID+/- mice survived completely. However, AID-/- mice could not completely block replication of the virus and their body weights decreased severely whereas AID+/- mice showed almost complete prevention from the reinfection. Depletion of CD8+ T cells by administration of an anti-CD8 monoclonal antibody caused slightly severer body weight loss but did not alter the survival rate of AID-/- mice in secondary infection. These results indicate that unmutated immunoglobulin (Ig)M alone is capable of protecting mice from death upon primary and secondary infections. Because the titers of virus-neutralizing antibodies were comparable between AID-/- and AID+/- mice at the time of the secondary infection, a defect of AID-/- mice in protection of morbidity might be due to the absence of either other Ig classes such as IgG, high affinity antibodies with SHM, or both.