A1M： To investigate the prevalence of celiac disease （CD） as well as CD marker antibodies and susceptibility HLA-DQ haplotypes in 134 karyotyped Down＇s syndrome （DS） patients. METHODS： Immunoglobulin A （IgA） ...A1M： To investigate the prevalence of celiac disease （CD） as well as CD marker antibodies and susceptibility HLA-DQ haplotypes in 134 karyotyped Down＇s syndrome （DS） patients. METHODS： Immunoglobulin A （IgA） and G （IgG） type anti-gliadin antibodies （AGA）, IgA type anti-tissue transglutaminase （tTG） antibodies （anti-tTG） with antigen of guinea pig and human source were determined by enzyme-linked immunosorbent assay and endomysium antibodies （EHA） by indirect immunofiuoresence test. HLA-DQA1＊0501/DQB1＊0201 （DQ2） was revealed by polymerase chain reaction. Celiac disease was diagnosed by revised ESPGHAN criteria. RESULTS： 41% of DS patients had AGA, 6.0% IgA anti-tTG with guinea pig antigen, and 3.0 % [gA EMA （all positive for anti-tTG with human tTG）. Subtotal villous atrophy was found in 5 out of 9 DS patients who had agreed to small bowel biopsy. One of them had DQA1＊0S01/DQB1＊0201 and anti-tTG and EMA i.e. typical for CD markers （this case also fulfilled the ESPGHAN diagnostic criteria）, but other four lacked these markers. Three non-biopsied DS patients had also most probably CD because DQA1＊0S01/DQB1＊0201 and IgA anti-tTG （EMA） were detected. Thus, the prevalence of CD among our DS patients population is 3.0 % （95 % of confidence interval [CI]： 0.1-5.9 %）. CONCLUSION： We confirm the increased frequency of CD among DS patients. In addition, we have revealed a subgroup of patients with subtotal villous atrophy but without characteristic for CD immunological and genetic markers. Whether these cases represent CD （with atypical immunopathogenesis） or some other immune enteropathy, requires further investigations.展开更多
The effect of lipopolysaccharide (LPS) on the exposure of platelet fibrinogen receptors was investigated. The results showed that:l)LPS increased the binding of fibrinogen-gold complexes to platelets and the labels we...The effect of lipopolysaccharide (LPS) on the exposure of platelet fibrinogen receptors was investigated. The results showed that:l)LPS increased the binding of fibrinogen-gold complexes to platelets and the labels were primarily limited to shape-changed platelets; 2) LPS caused a dose-dependent rise in intracellular Ca2+ concentration in platelets; 3)LPS induced the activation of platelet protein kinase C (PKC) and the phosphorylation of glycoprotein llla (GPllla) which was inhibited by H-7. All these results suggest that stimulation of platelets with LPS causes a conformational change in glycoprotein llb/llla (GPllb/llla)through platelet shape change and /or phosphorylation of GPllla via PKC, which serves to expose the fibrinogen binding sites of GPllb/llla on human platelets.展开更多
Objective:To study the role of intracellular calcium signal pathway in the down-regulation of aggrecan induced by cyclic tensile strain in the annulus fibrosus cells. Methods:The expression of aggrecan mRNA and core p...Objective:To study the role of intracellular calcium signal pathway in the down-regulation of aggrecan induced by cyclic tensile strain in the annulus fibrosus cells. Methods:The expression of aggrecan mRNA and core protein were respectively detected with RT-PCR and western blot after the channels transmitting calcium ions were blocked with EGTA, gadolinium and verapamil. Results :EGTA. gadolinium and verapamil partially prevented the effects of cyclic tensile strain on the expression of aggrecan in annulus fibrosus cells. Conclusion:The calcium signaling is involved in the down-regulation of proteoglycan resulting from cyclic tensile strain in the annulus fibrosus cells.展开更多
Overexpression of P-glycoprotein （P-gp） encoded by the multidrug resistance gene-1 （MDR-1） is the main mechanism responsible for multidrug resistance （MDR） in a majority of cancer cells. However, the mechanism b...Overexpression of P-glycoprotein （P-gp） encoded by the multidrug resistance gene-1 （MDR-1） is the main mechanism responsible for multidrug resistance （MDR） in a majority of cancer cells. However, the mechanism by which cancer cells acquire high levels of P-gp has not been well defined. Accumulating evidence suggests that nuclear receptors （NRs）, especially human pregnane X receptor （PXR）, play a crucial role in multidrug resistance. It has been shown that chemotherapeutic drug activates PXR and then enhances P-gp expression. Genetic knockdown or pharmacologic inhibition of PXR led to attenuation of drug-induced MDR1 over expression, implying that NRs may be an effective target to reverse multidrug resistance. Recent investigations suggested that transcriptional activity of NRs is mediated by methylases, the important enzymes involved in epigenetic regulation. Other epigenetic modifications, such as promoter methylation, histone deacetylases and microRNAs, were also found to be involved in activation of MDR1 promoter, though the underlying mechanisms are not thoroughly known. In this review, we summarized recent researches in the regulation of P-gp expression, with particular focus on NRs and epigenetics, aiming to provide references and options to reverse and/or prevent MDR in cancer treatment.展开更多
基金Supported by Estonian Science Foundation grants No. 4437 and 6514.
文摘A1M： To investigate the prevalence of celiac disease （CD） as well as CD marker antibodies and susceptibility HLA-DQ haplotypes in 134 karyotyped Down＇s syndrome （DS） patients. METHODS： Immunoglobulin A （IgA） and G （IgG） type anti-gliadin antibodies （AGA）, IgA type anti-tissue transglutaminase （tTG） antibodies （anti-tTG） with antigen of guinea pig and human source were determined by enzyme-linked immunosorbent assay and endomysium antibodies （EHA） by indirect immunofiuoresence test. HLA-DQA1＊0501/DQB1＊0201 （DQ2） was revealed by polymerase chain reaction. Celiac disease was diagnosed by revised ESPGHAN criteria. RESULTS： 41% of DS patients had AGA, 6.0% IgA anti-tTG with guinea pig antigen, and 3.0 % [gA EMA （all positive for anti-tTG with human tTG）. Subtotal villous atrophy was found in 5 out of 9 DS patients who had agreed to small bowel biopsy. One of them had DQA1＊0S01/DQB1＊0201 and anti-tTG and EMA i.e. typical for CD markers （this case also fulfilled the ESPGHAN diagnostic criteria）, but other four lacked these markers. Three non-biopsied DS patients had also most probably CD because DQA1＊0S01/DQB1＊0201 and IgA anti-tTG （EMA） were detected. Thus, the prevalence of CD among our DS patients population is 3.0 % （95 % of confidence interval [CI]： 0.1-5.9 %）. CONCLUSION： We confirm the increased frequency of CD among DS patients. In addition, we have revealed a subgroup of patients with subtotal villous atrophy but without characteristic for CD immunological and genetic markers. Whether these cases represent CD （with atypical immunopathogenesis） or some other immune enteropathy, requires further investigations.
文摘The effect of lipopolysaccharide (LPS) on the exposure of platelet fibrinogen receptors was investigated. The results showed that:l)LPS increased the binding of fibrinogen-gold complexes to platelets and the labels were primarily limited to shape-changed platelets; 2) LPS caused a dose-dependent rise in intracellular Ca2+ concentration in platelets; 3)LPS induced the activation of platelet protein kinase C (PKC) and the phosphorylation of glycoprotein llla (GPllla) which was inhibited by H-7. All these results suggest that stimulation of platelets with LPS causes a conformational change in glycoprotein llb/llla (GPllb/llla)through platelet shape change and /or phosphorylation of GPllla via PKC, which serves to expose the fibrinogen binding sites of GPllb/llla on human platelets.
文摘Objective:To study the role of intracellular calcium signal pathway in the down-regulation of aggrecan induced by cyclic tensile strain in the annulus fibrosus cells. Methods:The expression of aggrecan mRNA and core protein were respectively detected with RT-PCR and western blot after the channels transmitting calcium ions were blocked with EGTA, gadolinium and verapamil. Results :EGTA. gadolinium and verapamil partially prevented the effects of cyclic tensile strain on the expression of aggrecan in annulus fibrosus cells. Conclusion:The calcium signaling is involved in the down-regulation of proteoglycan resulting from cyclic tensile strain in the annulus fibrosus cells.
文摘Overexpression of P-glycoprotein （P-gp） encoded by the multidrug resistance gene-1 （MDR-1） is the main mechanism responsible for multidrug resistance （MDR） in a majority of cancer cells. However, the mechanism by which cancer cells acquire high levels of P-gp has not been well defined. Accumulating evidence suggests that nuclear receptors （NRs）, especially human pregnane X receptor （PXR）, play a crucial role in multidrug resistance. It has been shown that chemotherapeutic drug activates PXR and then enhances P-gp expression. Genetic knockdown or pharmacologic inhibition of PXR led to attenuation of drug-induced MDR1 over expression, implying that NRs may be an effective target to reverse multidrug resistance. Recent investigations suggested that transcriptional activity of NRs is mediated by methylases, the important enzymes involved in epigenetic regulation. Other epigenetic modifications, such as promoter methylation, histone deacetylases and microRNAs, were also found to be involved in activation of MDR1 promoter, though the underlying mechanisms are not thoroughly known. In this review, we summarized recent researches in the regulation of P-gp expression, with particular focus on NRs and epigenetics, aiming to provide references and options to reverse and/or prevent MDR in cancer treatment.
