Phagocytosis of IgA Immune Complexes by Human U937 Cells

Human promonocytic cell line U937 can express both IgAFc receptors ( FcαRⅠ, CD89 ) and IgG Fc receptors(FcαγⅠ, FcγRⅡ and FcγRⅢ)[1]. These receptors canmediate a variety of cell reactions including phagocytosis ofimmune complexes ( ICs ), degranulation, respiratorybursts, release of cytokines and enhancement of antibody dependent cell mediated cytotoxicity (ADCC) [2]. AfterIgA and IgG form ICs with their corresponding antigens,the ICs are bound by FcR on phagocyt…     

The Regulatory Role of IFN-γ on the Proliferation and Differentiation of Hematopoietic Stem and Progenitor Cells

The replenishment of all blood cell lineages is hierarchically organized by the process of hematopoiesis, which is based on the differentiation pathways of hematopoietic stem and progenitor cells (HSPCs). Due to the ability to balance between self-renewal and differentiation, hematopoietic stem cells (HSCs) can generate the appropriate cell type that is required by the immune system and peripheral blood in response to physiological or pathological conditions. Numerous studies have shown that some proinflammatory cytokines contribute to the regulation of the various hematopoietic compartments. Of these, IFN-γ is a type II interferon primarily produced by T cells and natural killer cells, and plays a major role in the defense against invading pathogens and transformed cancer cells; moreover, a growing amount of research indicates that it exerts negative or positive regulatory effect on hematopoiesis. Although IFN-γ is a widely regarded negative regulator of HSC proliferation, it also participates in some chronic infections or hematological malignancies that induce bone marrow failure. Recent studies have demonstrated unexpected effects of IFN-γ, including the promotion of HSC formation and the stimulation of myelopoiesis. Here, we review the direct and indirect effects of IFN-γ on hematopoiesis, as well as the underlying signaling mechanisms of how IFN-γ modulates the self-renewal, cell cycle entry, and proliferation of HSCs. Next, we describe how IFN-γ affects different stages of the lineage differentiation from HSCs. Finally, we discuss the relationship between IFN-γ and compensatory extramedullary hematopoiesis, as well as some related clinical diseases.     

A Primary Study of the Proliferation Sti mulation Effect by Pyrroloquinoline Quinone (PQQ) on Cultured Schwann Cells

1 IntroductionTissue engineering offers many advantages over allograft nerve transplantation, and it is a promising management for peripheral nerve deficit~([1]). Schwann cell (Sc), as the seed cell of peripheral nerve tissue engineering, functions as an important role. As a research material, large quantities of Scs are needed to further clarify its biological characters and testify its bio-compatibility with some newly developed nerve tubes. However, cultured Scs proliferate at a nearly st…     

Effect of Dehydroepiandrosterone Sulfate on Maturation and Functional Properties of Interferon-α-Induced Dendritic Cells

We studied the effect of adrenal cortex hormone dehydroepiandrosterone sulfate on maturation and functional activity of interferon-α-induced dendritic cells. Dehydroepiandrosterone sulfate stimulated differentiation and maturation of interferon-α-induced dendritic cell, which manifested in a decrease in the number of CD14⁺ cells and increase in the ratio of mature CD83⁺ dendritic cells expressing costimulatory molecules (CD80 and CD86). The induction of dendritic cell differentiation after treatment with dehydroepiandrosterone sulfate was accompanied by an increase in the production of interferon-γ. At the stage of dendritic cell maturation, the effect of dehydroepiandrosterone sulfate manifested in a 4-fold increase in tumor necrosis factor-α production. Dehydroepiandrosterone sulfate had little effect on the production of Th2/antiinfl ammatory cytokines at the stages of differentiation and maturation of interferon-α-induced dendritic cells. Dehydroepiandrosterone sulfate increased the ability of dendritic cells to stimulate Th1 cytokine production by T cells (interferon-γ). This hormone had no effect on the ability of interferon-α-induced dendritic cells to activate CD3⁺IL-4⁺T cells in mixed lymphocyte culture.     

Research of the Effect of the Shear Stress on Endothelial Cells

1 IntroductionCellular mechanism is one of the foundations of regenerating medicine and tissue engineering, which is also an advanced subject in cell mechanism in recent years~([1]). The form and function of a cell, and the growing, reproducing and death, even canceration are related to the characteristics of cell mechanism. While the research of the shear stress on endothelial cells is an important field in cell mechanism. The main bio-functions of endothelial cells are as follows: anti-cruor…     

Activin A-Induced Differentiation of Embryonic Stem Cells into Endoderm and Pancreatic Progenitors—The Influence of Differentiation Factors and Culture Conditions

The differentiation of murine and human embryonic stem (ES) cells into pancreatic cell types has been shown by several methods including spontaneous differentiation, formation of multi-lineage progenitors, lineage selection or transgene expression. However, these strategies led to a mixture of cells of all three primary germ layers and only a low percentage of definitive endoderm cells giving rise to pancreas, liver, lung and intestine. To reproducibly generate functional insulin-producing cells, ES cells have to be differentiated via definitive endoderm and pancreatic endocrine progenitors recapitulating the in vivo development. Activin A, a member of the transforming growth factor beta superfamily, has been shown to induce definitive endoderm cells dependent on concentration, culture conditions and time of application. Moreover, serum components or contamination by feeder cells as well as differentiation and proliferation factors are critical for successful generation of activin A-induced ES cells into endoderm and pancreatic cells. The review presents an overview on those factors that influence activin A activity on endoderm and endocrine progenitor cells and determines the role of signaling factors in the differentiation process into the pancreatic lineage. Sabine Sulzbacher and Insa S. Schroeder contributed equally to this work.     

Synergistic Effect of Histamine and TNF-α on Monocyte Adhesion to Vascular Endothelial Cells

The histamine level is high during allergic attacks, and patients with allergy may have chronic inflammatory conditions at which tumor necrosis factor (TNF)-α is extensively released by macrophages. Here, in vitro static and microfluidic flow assays were conducted to investigate the combined influence of histamine and TNF-α on adhesion of monocytic THP-1 cells to human umbilical vein endothelial cells (HUVEC). In a static assay, histamine stimulation of TNF-α-activated HUVEC elevated the number of attached THP-1 cells. In a flow assay, the number of crawling and firmly adherent THP-1 cells was higher on TNF-α + histamine activated HUVEC than on HUVEC activated by TNF-α alone. This synergistic effect of histamine and TNF-α is caused by the increased endothelial surface expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin. Since the exposure of TNF-α-activated endothelium to histamine favors monocyte recruitment, it may be a serious risk factor for atherosclerosis and other inflammatory disorders.     

Effect of Adhesion Molecule P-selectin and Dendritic Cells on Tubulointerstitial Lesions in IgA Nephropathy

It is well appreciated that tubulointerstitial lesions (TILs)associated with renal insufficiency are frequently observedin IgA nephropathy. TILs may be induced by cell mediat ed immune responses and are closely related to the progno sis of the disease […     

Effect of Pregnancy Specific β1-Glycoprotein on the Replicative Potential of Naïve T Cells and Immune Memory T Cells

Bulletin of Experimental Biology and Medicine - We studied the effects of pregnancy-specific β1-glycoprotein (PSG) on the replicative potential of naïve T cells (CD45RA+) and immune...     

Effects of interferon-γ on cell differentiation and cytokine production of a human monoblast cell line,U937

The U937 cell, a human monoblast cell line, has been used as a model to study the function of human monocytes. We investigated the effects of interferon- (IFN-) on Superoxide anion (O ₂ ^– ) production, cell surface antigens, and cytokine production of U937 cells. IFN- treatment enhanced O ₂ ^– production of fMLP or PMA-stimulated U937 cells. IFN- increased the ratio of CD23 and CD 11b positive cells. The fluorescence intensity of CD14 and CD25 was enhanced by IFN- treatment. U937 cells produced IL-1, IL-1, IL-6, and TNF- by lipopolysaccharide (LPS) stimulation. IFN- treatment enhanced TNF- production, but decreased IL-6 production. These results suggest that IFN- differentiates U937 cells to monocytelike cells and it regulates the production systems of IL-6 and TNF- separately in U937 cells.     

Distinct Deleterious Effects of Cyclosporine and Tacrolimus and Combined Tacrolimus–Sirolimus on Endothelial Cells: Protective Effect of Defibrotide

Endothelial dysfunction seems to be a key factor in the development of several complications observed early after hematopoietic stem cell transplantation (HSCT). The conditioning regimen and many other factors associated with the procedure are responsible for this endothelial damage. The effects of immunosuppressive agents on endothelial function have not been explored in detail. We evaluated the effects of 3 drugs commonly used in HSCT: 2 calcineurin inhibitors, cyclosporine A (CSA) and tacrolimus (TAC), and an inhibitor of mTOR, sirolimus (SIR). We also evaluated the effect of the combination of TAC and SIR (TAC+SIR), which is used increasingly in clinical practice. Microvascular endothelial cells (HMEC-1) were exposed to these drugs to evaluate changes in (1) intercellular adhesion molecule (ICAM)-1 expression on the cell surface, assessed by immunofluorescence labeling and expressed as the mean gray value (MGV); (2) reactivity of the extracellular matrix (ECM) toward platelets, upon exposure of the ECM to circulating blood; and (3) whole-blood clot formation, assessed by thromboelastometry. Studies were conducted in the absence and presence of defibrotide (DF) to assess its possible protective effect. The exposure of HMEC-1 to CSA and TAC+SIR significantly increased the expression of ICAM-1 (157.5 ± 11.6 and 153.4 ± 9.5 MGV, respectively, versus 105.7 ± 6.5 MGV in controls [both P < .05]). TAC applied alone increased ICAM-1 slightly (120.3 ± 8.2 MGV), and SIR had no effect (108.9 ± 7.4 MGV). ECM reactivity increased significantly only in response to CSA (surface covered by platelets of 41.2% ± 5.4% versus 30.1% ± 2.0%, P < .05). DF attenuated all these changes. No significant changes in the viscoelastic properties of clot formation were observed in any condition with blood samples incubated in vitro. In conclusion, CSA and TAC+SIR had a proinflammatory effect, but only CSA exhibited an additional prothrombotic effect. Interestingly, DF exerted clear protective anti-inflammatory and antithrombotic effects on the endothelium.     

Suppressive Effect of 19-nor-1α-25-Dihydroxyvitamin D2 on Gastric Cancer Cells and Peritoneal Metastasis Model

The active metabolite of vitamin D, 1,25-dihydroxyvitamin D3 (calcitriol), inhibits the growth of several types of human cancer cells in vitro, but its therapeutic use is limited because it causes hypercalcemia. Among its analogs, 19-nor-1,25-dihydroxyvitamin D(2) (paricalcitol), has fewer calcemic effects and exhibits an activity equipotent to that of calcitriol. We assessed the antitumor and anti-inflammatory effects of paricalcitol in gastric cancer cells, and evaluated the potential role of vitamin D in the treatment of peritoneal metastatic gastric cancer. In this study, treatment with paricalcitol inhibited gastric cancer cell growth and induced cell cycle arrest. Paricalcitol also induced apoptosis and showed anti-inflammatory activity. Moreover, the growth of intraperitoneal metastases in vivo was reduced in mice treated with paricalcitol. (18)F-FDG uptake was significantly lower in the paricalcitol group compared to control group (SUV; control group 13.2 ± 5.3 vs paricalcitol group 4.5 ± 3.0). Intraperitoneal tumor volume was significantly lower in paricalcitol treated mice (control group 353.2 ± 22.9 mm(3) vs paricalcitol group 252.0 ± 8.4 mm(3)). These results suggest that the vitamin D analog, paricalcitol, has anticancer activity on gastric cancer cells by regulation of the cell cycle, apoptosis, and inflammation.     

Effect of Cell–Cell Interactions on the Observable Strength of Adhesion of Sheets of Cells

Previous research in cellular adhesion has focused primarily on studying isolated cells under conditions where cells do not interact with each other. However, in vivo cells form sheets where both cell–substratum and cell–cell interactions contribute to the overall adhesive behavior. Our understanding of how cell–cell and cell–substratum interactions affect the overall process of cell adhesion in these situations is limited. To address this problem, we developed a systematic approach to evaluate how cell–cell and cell–substratum interactions affect the critical shear stress for detachment for semiconfluent and confluent sheets of cells. Our studies were based on subjecting cultures of adherent cells to a defined hydrodynamic flow in a radial-flow chamber with a gap height of 140 m. Using phase-contrast microscope imaging and analysis we measured shear-dependent patterns of detachment as a function of the extent of cell confluency. Our results show that the critical shear stress for detachment is maximum at intermediate extents of confluency of 10%–40%. These results have important implications for sodding vascular grafts and tissue engineering. © 1999 Biomedical Engineering Society. PAC99: 8718-h, 8719Rr     

Effect of Transplantation of Neural Stem and Progenitor Cells on Memory in Animals with Alzheimer’s Type Neurodegeneration

Bulletin of Experimental Biology and Medicine - The effects of systemic and intracerebral transplantation of human fetal neural stem and progenitor cells were studied on the model of olfactory...     

Effect of melatonin on α-synuclein self-assembly and cytotoxicity

α-Synuclein (αS) assembly has been implicated as a critical step in the development of Lewy body diseases such as Parkinson's disease and dementia with Lewy bodies. Melatonin (Mel), a secretory product of the pineal gland, is known to have beneficial effects such as an antioxidant function and neuroprotection. To elucidate whether Mel has an antiassembly effect, here we used circular dichroism spectroscopy, photoinduced crosslinking of unmodified proteins, thioflavin S fluorescence, size exclusion chromatography, electron microscopy and atomic force microscopy to examine the effects of Mel on the αS assembly. We also examined the effects of Mel on αS-induced cytotoxicity by assaying 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide metabolism in αS-treated, primary neuronal cells. Initial studies revealed that Mel blocked αS fibril formation as well as destabilizing preformed αS fibrils. Subsequent evaluation of the assembly-stage specificity of the effect showed that Mel was able to inhibit protofibril formation, oligomerization, and secondary structure transitions. Importantly, Mel decreased αS-induced cytotoxicity. These data suggest a mechanism of action for Mel, inhibition of assembly of toxic polymers and protection of neurons from their effect.     

A Modified rhTGF-β1 and rhBMP-2 Are Effective in Initiating a Chondro-Osseous Differentiation Pathway in Bone Marrow Cells Cultured In Vitro

Rat bone marrow cells were cultured in vitro in a collagen-gel medium at 0.5% fetal bovine serum concentration for 10 days in the presence of recombinant human transforming growth factor-beta-1, genetically engineered to contain a collagen binding domain (rhTGF- &#103 1-F2), or a commercial rhTGF- &#103 1. To compare the effects of TGF- &#103 s with other growth factors in which the osteogenic capacity has been widely documented, a recombinant human bone morphogenetic protein (rhBMP-2) was evaluated. Once serum conditions compatible with growth were re-established, the selected cells were cultured for 6 more days in the presence of the growth factor. In the last 2 days, dexamethasone (dex) and &#103 -glycerophosphate ( &#103 -GP) were added to promote osteogenesis. After this 16-day period, cells were placed into diffusion chambers or demineralized bone matrix (DBM) implants, and implanted subdermally on the backs of rats for 28 days. Biochemical, histological, and immunohistochemistry analysis provided evidence of cartilage (commercial rhTGF- &#103 1-treated cells), osteoid (rhTGF- &#103 1-F2-treated cells), and bone tissues (rhBMP-2 treated cells), inside the diffusion chambers, whereas bone, cartilage, and osteoid were observed inside the DBM implants under any of the three growth factors effect. Our study advances the technology capable of selecting a cell population from bone marrow that, in the presence of rhTGF- &#103 1 or rhBMP-2 in vitro, achieves chondro-osteogenic potential in vitro and in vivo.     

Effect of 45° Reclining Sitting Posture on Swallowing in Patients with Dysphagia

Purpose

To determine the effect of a 45° reclining sitting posture on swallowing in patients with dysphagia.

Materials and Methods

Thirty-four patients with dysphagia were evaluated. Videofluoroscopic swallowing study was performed for each patient in 90° upright and in 45° reclining sitting posture. Patients swallowed 5 types of boluses twice: sequentially 2 mL thin liquid, 5 mL thin liquid, thick liquid, yogurt, and cooked rice. Data such as the penetration-aspiration scale (PAS), oral transit time (OTT), pharyngeal delay time (PDT), pharyngeal transit time (PTT), residue in valleculae and pyriform sinuses, premature bolus loss, and nasal penetration were obtained.

Results

The mean PAS on the 2 mL thin liquid decreased significantly in the 45° reclining sitting posture (p=0.007). The mean PAS on 5 mL thin liquid in the 45° reclining sitting posture showed decreasing tendency. The residue in valleculae decreased significantly for all boluses in the 45° reclining sitting posture (p<0.001, p=0.002, p=0.003, p<0.001, p=0.020, respectively). The residue in pyriform sinuses increased significantly on 5 mL thin liquid, thick liquid, and yogurt (p=0.031, p=0.020, p=0.002, respectively). There were no significant differences in OTT, PDT, PTT, premature bolus loss, and nasal penetration between both postures.

Conclusion

PAS on 2 mL thin liquid and residue in valleculae on all types of boluses were decreased in a 45° reclining sitting posture. Therefore, we believe that the 45° reclining sitting posture on swallowing is beneficial for the patients with penetration or aspiration on small amounts of thin liquid and large amounts of residue in valleculae.     

Isolation and Culture of a kind of Derived Cells from Differentiation Group Of Murine ESC-like Cell and Their Traits in Culture

1IntroductionInthe process of culturing ESC-like cell from murine blastula ,we find that even if no inducing factor was added, ESC-like cellmasses can differentinto many kinds of cell groups .Study onthe bi-ological traits ,culturing and change of functional genetics of thosecell groups will be of great meaningtofind outthe mechanismof dif-ferentiation and possible value of ESC-like cells . UPto now,thereare not many references and reports on this aspect .This article in-troduces a kind of…