Role of pentobarbitone anaesthesia and sympathetic tone in the haemodynamic effects of isosorbide dinitrate in rats with cirrhosis

The haemodynamic effects of nitrovasodilators and their mechanisms of action on portal hypertension remain unclear. The splanchnic and systemic haemodynamic response to the infusion of isosorbide dinitrate (100 μg/kg per min), a nitrovasodilator, was investigated in cirrhotic rats. The role of the conscious state in the haemodynamic response to isosorbide dinitrate was examined using rats that were anaesthetized with pentobarbitone. The role of sympathetic tone in the haemodynamic response to isosorbide dinitrate was examined using rats pretreated with the ganglion blocker hexamethonium. Isosorbide dinitrate had no haemodynamic effects in conscious, unblocked normal and cirrhotic rats. Isosorbide dinitrate had no haemodynamic effects in normal and cirrhotic rats treated with hexamethonium. In normal anaesthetized rats, isosorbide dinitrate significantly decreased systemic vascular resistance (414±25 vs 290±26 dyn.s/cm⁵ per 100 g). In cirrhotic anaesthetized rats, isosorbide dinitrate significantly decreased mean arterial pressure (98±6 vs 79±7 mmHg), systemic vascular resistance (318±30 vs 207±10 dyn.s/cm⁵ per 100 g), portal pressure (14.0±1.0 vs 11.3±0.9 mmHg) and portal territory vascular resistance (1362±163 vs 1031±182 dyn.s/cm⁵ per 100 g). In conclusion, this study shows that the portal hypotensive effects of isosorbide dinitrate depend upon the alterations of vascular tone by pentobarbitone.     

Assessment of class-specific antibodies against denatured DNA in patients with systemic lupus erythematosus

In this retrospective study 103 serum samples from 16 females with systemic lupus erythematosus (SLE), obtained during a mean follow-up time of 2 years, were investigated for the presence of anti-denatured [single-stranded (ss)] DNA antibodies of the IgG, IgM, and IgA classes. The anti-ssDNA antibodies were determined by an enzyme-linked immunosorbent assay (ELISA), and the results were expressed in three ways: as units derived from a single serum dilution and as two parameters,E andA, calculated from the dose-response curve,E being an estimate of the effective amount of antibodies andA a function of the reaction constant between the antigen and the antibody. The simultaneous occurrence of anti-ssDNA antibodies of all three immunoglobulin classes was seen most often in the patients with the shortest duration of the disease. Clinically active disease was found to correlate with high reaction constants of the IgA anti-ssDNA antibodies. There was also an association between the IgA anti-ssDNA antibody levels and the presence of nephritis. Great fluctuations in the amounts of effective antibodies of the IgG class were seen in seven patients, in six of whom changes in the disease activity also were seen. Changes in the disease activity were unaccompanied by fluctuations in the IgG anti-ssDNA levels in four patients; two of these patients were positive for antibodies against extractable nuclear antigens. We conclude that it is of value to express the results of the anti-ssDNA ELISA as a function of the dose-response curve when monitoring patients with SLE and that immunoglobulin class-specific determinations of anti-ssDNA antibodies may provide information about the disease activity in many patients with SLE.     

Similar frequency of autoantibodies against 70-kD class heat-shock proteins in healthy subjects and systemic lupus erythematosus patients

Stress or heat-shock proteins may be involved in the initiation and perpetuation of autoimmune diseases. In order to investigate a possible role of autoantibodies against the 70-kD family of heat-shock proteins in systemic lupus erythematosus (SLE), sera of SLE patients and healthy subjects were tested for the presence of IgG and IgM antibodies to 70-kD class proteins. These proteins were purified by affinity chromatography on ATP-agarose and used in Western blotting studies. The data obtained revealed that antibodies to the 72-kD and the 73-kD heat-shock proteins occurred with similar frequencies both in healthy subjects and SLE patients. Thus, approximately 20% of the sera in each group contained IgG antibodies, and IgM antibodies were detected in about 30% of the sera tested. Moreover, in SLE patients no association between the occurrence and litre of these antibodies and disease activity was found. These data suggest that antibodies to the 70-kD class heat-shock proteins are naturally occurring and argue therefore against an involvement of these antibodies in the pathogenesis of SLE.     

Enhanced production of transforming growth factor-beta (TGF-beta) during autologous mixed lymphocyte reaction of systemic sclerosis patients.

Systemic sclerosis (SSc) is characterized by systemic fibrosis and microvascular lesions. As TGF-beta is suggested to be related to skin fibrosis, we examined the production of TGF-beta from peripheral mononuclear cells (MNC) of SSc patients. Since anti-TGF-beta neutralizing antibody improved the defective proliferative response in autologous mixed lymphocyte reaction (AMLR) of SSc patients, TGF-beta was thought to participate in the decreased AMLR of SSc patients. Greater amounts of TGF-beta in the active as well as in the latent forms were produced during AMLR of SSc patients than that of normal subjects. It was suggested that TGF-beta excessively produced from the MNC of SSc patients might play a major role in the fibrosis of the patients during AMLR-like in vivo responses.     

Triggering of respiratory burst by phagocytosis in monocytes of patients with systemic lupus erythematosus.

The triggering of the respiratory burst by phagocytosis via different receptors in monocytes of patients with systemic lupus erythematosus (SLE) was investigated. The superoxide anion synthesis was assayed by reduction of ferricytochrome C that was inhibited by superoxide dismutase. The mononuclear cell suspensions were triggered by IgG-coated latex, C3 complement fragment-coated and uncoated yeast (Saccharomyces cerevisiae). Superoxide generation induced by phagocytosis via Fc gamma R was decreased in monocytes of patients with SLE. On the other hand, MoAbs against Fc gamma RI, Fc gamma RII and especially CR3 could also induce superoxide anion synthesis. At the same time, superoxide generation induced by anti-CR3 could be inhibited with C3-coated yeast.     

Subpopulations of CD4+ cells in lpr/lpr mice: differences in expression of T cell receptor/CD3 complex and proliferative responses.

CD4+ cells from autoimmune-prone C57BL/6 lpr/lpr mice contain two subpopulations, B220-CD4+ and B220+CD4+ cells. Highly purified B220-CD4+ cells from C57BL/6 +/+ and lpr/lpr mice were examined by comparing functional characteristics and expression of cell surface antigens and T cell receptor (TcR)/CD3 complex. Both lpr B220+CD4+ and B220+CD4-CD8- cells, most of which were PgP-1 positive, expressed TcR/CD3 complex on the cell surface at lower level as compared with B220-CD4+ cells of age-matched normal mice. In addition, the B2200-CD4+ cells were heterogeneous on the basis of surface expression of PgP-1 and CD3 antigens. Normal levels of TcR C alpha-, C beta- and V beta 8-specific mRNA were found in the B220-CD4+ cells and B220+CD4+ cells as compared with normal B220-CD4+ cells, while V beta 8-specific mRNA was preferentially expressed only by B220+CD4-CD8- cells. Either B220+CD4+ cells and B220+CD4-CD8- cells failed to respond to anti-CD3 monoclonal antibody (MoAb) as assessed by proliferative responses and production of interleukin-2 (IL-2). However, appreciable levels of reactivity to anti-CD3 MoAb were detected in the B220-CD4+ cells, although the responsiveness of this subset to such stimuli were reduced, compared with those of normal control. These results indicate that the B220-CD4+ cells in lpr mice are phenotypically and functionally distinct from normal B220-CD4+ cells.     

Adsorption of anti-dsDNA antibodies by immobilized polyanionic compounds.

Antibodies to dsDNA are characteristically present in serum from patients with systemic lupus erythematosus (SLE), and have been shown to have the capacity to react with various molecules bearing repeating negative charges. After a number of polymeric or monomeric molecules with differently charged groups and hydrophobic molecules had been coupled covalently as ligands on cellulose gel, the adsorption capacities of the ligands for anti-dsDNA antibodies were evaluated. It was found that gels coupled with polyanionic dextran sulphate (DXS) and polyacrylic acid (PA) and monoanionic sulphanilic acid (SA) absorbed anti-dsDNA antibodies effectively. DXS gel also adsorbed antibodies to ssDNA and heparan sulphate, antigens with repeating negatively charged moieties, while no ligand was able to adsorb anti-nRNP antibodies. The finding that DXS gels adsorbed anti-dsDNA antibody in proportion to their charge density, and that the interaction between anti-dsDNA and DXS gel is broken readily by an increase in ionic strength, indicated that the binding is ionic in nature. Moreover, virtually all F(ab')2 anti-dsDNA became adsorbed onto the DXS gels, suggesting that the binding occurred via specific antigen-binding sites on the antibody molecule. Binding of these polyanion-binding autoantibodies with anionic sites in the glomerular basement membrane may therefore cause the tissue damage observed in SLE.     

PBX1基因剪切体表达与SLE的相关研究

了解PBX1基因各种剪切体的表达在SLE患者和正常人中是否存在差异 ,探讨PBX1的表达与SLE发病的相关性。通过PCR扩增及毛细管芯片电泳 ,确证剪切体h、k、l存在于人体 ;通过实时荧光定量PCR技术 ,对剪切体h、k、l分别进行SLE患者组和正常组的mRNA表达定量比较。结果发现这 3种剪切体在患者组中的表达较正常人明显降低 ,正常人的表达是SLE的 9～ 12倍。重度患者的k、l剪切体与轻中度的病人相比表达明显降低 ,并发狼疮性肾炎的病人k剪切体的表达较无肾累及的病人显著降低。说明PBX1基因剪切体h、k、l在SLE患者中mRNA表达水平下降 ,并与SLE活动度及肾累及有关。提示机体通过PBX1的表达量的调节可能参与SLE的发病