贝母提取物对异丙肾上腺素诱导心肌H9c2细胞肥大的干预作用

目的:研究贝母提取物(FE)对异丙肾上腺素(Iso)诱导H9c2心肌细胞肥大(CH)的干预作用.方法:采用体外培养心肌H9c2细胞,MTT法测定心肌H9c2细胞存活率;细胞分4组(n=10):对照组、2 μmol/L Iso(模型)组、2 μmol/L Iso+FE 400 μg/L组、2 μmol/LIso+FE 1...     

Impairment in a negative regulatory system for TCR signaling in CD4+ T cells from old mice

To examine the involvement of lipid rafts in an age-associated decline in T cell function, we analyzed the effect of aging on the constituents of lipid rafts in resting mouse CD4(+) T cells. We found a pronounced, age-dependent reduction in PAG/Cbp, which is involved in the regulation of Src family kinases (SFKs) by recruiting Csk (a negative regulator of SFKs) to lipid rafts. This reduction is specific for T cells and is attributed, at least in part, to the reduction in its mRNA level. The reduction of PAG accompanies marked impairment in recruiting Csk to lipid rafts and a concomitant decrease in the inactive forms of SFKs. These findings indicate that old mouse CD4(+) T cells have a defect in a negative SFK regulatory system.     

G蛋白调节剂对梨花粉萌发及花粉胞内Ca2+浓度变化的影响

用激光共聚焦技术研究了异三聚体G蛋白活性调节剂对梨花粉萌发、花粉管生长及花粉细胞内游离钙离子浓度动态的影响。结果表明：异三聚体G蛋白激活剂霍乱毒素(CTX)可促进梨花粉萌发与花粉管生长,而其抑制剂百日咳毒素(PTX)则抑制花粉萌发与花粉管生长;霍乱毒素处理后,花粉细胞内产生特异性的“钙瞬变”信号,而百日咳毒素处理后则引起花粉细胞内游离钙离子浓度的持续下降。这表明：异三聚体G蛋白可能参与了梨花粉萌发与花粉管生长的调控过程,G蛋白的活性变化对花粉萌发的效应可能是通过调控花粉细胞内游离Ca^2 浓度的动态变化产生特异性的钙信号来实现的。     

The �æ� variant of T cell large granular lymphocyte leukemia is very similar to the common ���� type: report of two cases

The vast majority of cases of T cell large granular lymphocyte (T-LGL) leukemia have a CD3+, CD4−, CD8+ phenotype and express the αβ T cell receptor. Whether the rare γδ variant should be included in the same diagnostic category is currently unclear. Two well-characterized cases of γδ T-LGL leukemia were identified by our laboratory in 2007. These two cases and other reports of γδ T-LGL leukemia were compared with the common αβ variant. Other than more often being negative for both CD4 and CD8 (in about 35% to 40% of cases), the γδ variant of T-LGL leukemia is similar to the common αβ type in virtually all respects and should be included in the general category of T-LGL leukemia. However, it is important to exclude other more aggressive γδ T cell lymphoproliferative disorders.     

Cetp and exchangeable apoproteins. Common features in lipid binding activity

Tuftsin, a tetrapeptide (Thr-Lys-Pro-Arg) is known to potentiate the immunogenic activity of antigen-fed macrophages. The present study describes the mechanism of action of tuftsin in leprosy patients throughout the spectrum of the disease in vitro as a function of culture age in terms of (A) involvement of second messengers cAMP, cGMP and [Ca2+]i and (B) number of tuftsin binding sites/and their relative affinities on the monocytes/macrophages. There is apparently no direct involvement of either cAMP or cGMP while comparing the stimulated and unstimulated cultures during in vitro differentiation of monocytes (days 1, 3 and 7) or with the spectrum of the disease. Inhibition of superoxide anion release either by verapamil or with Quin 2 clearly demonstrated the involvement of [Ca2+]i as a second messenger during activation of monocytes/macrophages with tuftsin. Scatchard analysis of radiolabelled tuftsin binding data showed only one type of tuftsin receptor (low affinity) on BL/LL monoc ytes/ macrophages and normal and BT/TT cultures showed a gradual change in receptor number and affinities (low to high) with the maturation of monocytes to macrophages in contrast to BL/LL groups which displayed significantly less number of receptors. This study elicits a model which depicts that the biological responses/metabolic functions of early monocytes of normal and BT/TT gradually increase with the age of the culture till day 3 and tapers off thereafter in the older (day 7) cultures, whereas the monocytes/macrophages of BL/LL group are metabolically active only on day 1. The present study thereby implies that the clearance of leprosy bacilli from lepromatous leprosy lesions as a consequence of local or systemic immunotherapy (in the present study, the macrophage modulation by tuftsin) depends on the influx of new competent macrophages, rather than the local activation of resident lepromatous macrophages.     

细菌中钙信号的作用

摘要：越来越多的实验证明二价钙离子（Ca2+）在细菌中有重要调控作用。本文从Ca2+ 信号对细菌生理的影响、细胞内Ca2+ 浓度及测定方法、细菌中Ca2+ 的运输和Ca2+ 结合蛋白四个方面综述了目前细菌中钙信号的研究进展。     

CD226单克隆抗体诱导人脐静脉内皮细胞胞质钙离子浓度的变化

为观察CD226单克隆抗体(mAb)对培养人脐静脉内皮细胞(HUVECs)胞质钙离子变化的影响,我们用Fluo-3作为钙指示剂,用激光共聚焦显微镜观测不同状态下CD226 mAb作用后HUVECs胞质钙离子[Ca2 ]i的变化。结果发现：(1)用Hanks液平衡,CD226 mAb作用后HUVECs[Ca2 ]i水平缓慢升高后回到原位;加入二抗(羊抗鼠IgG)交联后[Ca2 ]i水平有较大幅度的升高,随后回到原位,与此同时,细胞外液中[Ca2 ]。水平有一定程度的下降;(2)用D-Hanks液平衡,CD226 mAb作用后HUVECs[Ca2 ]i水平无显著变化,加入二抗发生交联作用后,[Ca2 ]：水平有较大幅度的下降;(3)用EGTA预处理后,CD226 mAb及其二抗交联对HUVECs[Ca2 ]i变化无显著影响。以上结果提示,CD226mAb及其二抗交联可诱导不同状态的HUVECs胞质钙离子水平发生不同程度的变化,从而参与一系列的生理和病理过程。     

Synthetic β-endorphin-like peptide immunorphin binds to non-opioid receptors for β-endorphin on T lymphocytes

The synthetic decapeptide H-SLTCLVKGFY-OH (termed immunorphin) corresponding to the sequence 364–373 of the CH3 domain of human immunoglobulin G heavy chain was found to compete with [¹²⁵I]β-endorphin for high-affinity receptors on T lymphocytes from the blood of healthy donors (K_i = 0.6 nM). Besides immunorphin, its synthetic fragments H-Val-Lys-Gly-Phe-Tyr-OH (K_i = 15 nM), H-Leu-Val-Lys-Gly-Phe-Tyr-OH (K_i = 8.0 nM), H-Cys-Leu-Val-Lys-Gly-Phe-Tyr-OH (K_i = 3.4 nM), H-Thr-Cys-Leu-Val-Lys-Gly-Phe-Tyr-OH (K_i = 2.2 nM), H-Leu-Thr-Cys-Leu-Val-Lys-Gly-Phe-Tyr-OH (K_i = 1.0 nM) possessed the ability to inhibit specific binding of [¹²⁵I]β-endorphin to T lymphocytes. Tests of the specificity of the receptors revealed that they are not sensitive to naloxone and Met-enkephalin, i.e. they are not opioid receptors. K_d values characterizing the specific binding of ¹²⁵I- labeled immunorphin and its fragment H-Val-Lys-Gly-Phe-Tyr-OH to the receptors have been determined to be 7.4 nM and 36.3 nM, respectively.     

Comparative study on the effect of phosphorylated TCR ζ chain ITAM sequences on early activation events in Jurkat T cells

One of the main dilemma in T cell receptor (TCR) signal transduction is whether the presence of multiple Immunoreceptor Tyrosine-based Activation Motifs (ITAMs) within the TCR signaling module serves for signal amplification or signal distribution. To contribute to answer this question, we analyzed the effect of synthetic oligopeptides representing the three bi-phosphorylated ζ chain-ITAMs on the early signaling events in permeabilized leukemia T cells. Our main observations were as follows: 1/Stimulation of the cells with the bi-phosphorylated membrane proximal and central ITAMs (ζ (1)y^py^p and ζ (2)y^py^p, respectively) resulted in a strong phosphorylation of proteins with a similar pattern. In contrast, the membrane distal ITAM, ζ (3)y^py^p had a reduced ability to promote tyrosine phosphorylation and failed to induce the phosphorylation of a number of proteins. 2/ The phospho-peptide induced tyrosine phosphorylation events were at least partially mediated by p56^lck and Syk/ZAP70 protein tyrosine kinases as it was shown in p56^lck and Syk/ZAP70 deficient Jurkat variants. 3/The patterns of the association of the adaptor protein, Grb2 with tyrosine phosphorylated proteins following cell stimulation with the bi-phosphorylated membrane proximal or the central ITAMs were similar, while the membrane distal ITAM was unable to induce any of these associations.

Our data provide additional evidence that the three ζITAMs differ in their capacity to induce tyrosine phosphorylation of intracellular proteins in permeabilized T cells, depending to their primary sequence. The first and second ITAM sequences of the ζ chain may have similar but not totally overlapping functions. This conclusion results from their similar but not identical abilities to induce tyrosine phosphorylation and association of Grb-2 with intracellular phosphoproteins. In contrast, the third ITAM (ζ3) may have distinct functions since this peptide fails to induce tyrosine phosphorylation of a number of proteins compared to the other two ITAMs, and it is unable to induce either new association or the increase in the amount of Grb-2 associated phosphoproteins.     

Effect of clomiphene on Ca movement in human prostate cancer cells

The effect of clomiphene, an ovulation-inducing agent, on cytosolic free Ca²⁺ levels ([Ca²⁺]_i) in populations of PC3 human prostate cancer cells was explored by using fura-2 as a Ca²⁺ indicator. Clomiphene at concentrations between 10-50 μM increased [Ca²⁺]_i in a concentration-dependent manner. The [Ca²⁺]_i signal was biphasic with an initial rise and a slow decay. Ca²⁺ removal inhibited the Ca²⁺ signal by 41%. Adding 3 mM Ca²⁺ increased [Ca²⁺]_i in cells pretreated with clomiphene in Ca²⁺-free medium, confirming that clomiphene induced Ca²⁺ entry. In Ca²⁺-free medium, pretreatment with 50 μM brefeldin A (to permeabilize the Golgi complex), 1 μM thapsigargin (to inhibit the endoplasmic reticulum Ca²⁺ pump), and 2 μM carbonylcyanide m-chlorophenylhydrazone (to uncouple mitochondria) inhibited 25% of 50 μM clomiphene-induced store Ca²⁺ release. Conversely, pretreatment with 50 μM clomiphene in Ca²⁺-free medium abolished the [Ca²⁺]_i increase induced by brefeldin A, thapsigargin or carbonylcyanide m-chlorophenylhydrazone. The 50 μM clomiphene-induced Ca²⁺release was unaltered by inhibiting phospholipase C with 2 μM 1-(6-((17β-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122). Trypan blue exclusion assay suggested that incubation with clomiphene (50 μM) for 2-15 min induced time-dependent decrease in cell viability by 10-50%. Collectively, the results suggest that clomiphene induced [Ca²⁺]_i increases in PC3 cells by releasing store Ca²⁺ from multiple stores in an phospholipase C-independent manner, and by activating Ca²⁺ influx; and clomiphene was of mild cytotoxicity.