小儿肾病、乙肝患者血清CaM与抗CaM自身抗体的测定研究

目的研究小儿疾病患者血清中CaM含量和抗CaM自身抗体阳性检出水，探讨CaM及抗CaM抗体与临床小儿疾病的关系。方法优化实验反应条件，建立检测CaM和抗CaM抗体的ELISA测定方法，并将其初步应用于临床小儿疾病患者血清CaM和抗CaM自身抗体水平测定。结果优化后的ELISA对CaM和抗CaM自身抗体的实验结果特异、敏感、可靠。在CaM浓度为39w／ml-2500ng/ml范围内，该法对CaM的测定具有良好的线性关系，相关系数（r）大于0．99。临床研究结果表明，各类小儿肾脏疾病血清CaM含量与抗CaM自身抗体均处在与正常对照组相同的水平。但在小儿乙型肝炎患者血清中，两者水平均显著高于正常对照组。25例被检者中分别有5例CaM水平升高，有6例为抗CaM自身抗体阳性，其中有5例为二者水平同时升高。结论小儿在感染乙型肝炎病毒的发病过程中，即伴有一定程度的CaM和抗CaM自身抗体水平升高，据此推测抗CaM抗体在继发引起小儿自身免疫性肝损害的过程中可能起一定作用。     

Calmodulin antagonists promote TRA-8 therapy of resistant pancreatic cancer

Pancreatic cancer is highly malignant with limited therapy and a poor prognosis. TRAIL-activating therapy has been promising, however, clinical trials have shown resistance and limited responses of pancreatic cancers. We investigated the effects of calmodulin(CaM) antagonists, trifluoperazine(TFP) and tamoxifen(TMX), on TRA-8-induced apoptosis and tumorigenesis of TRA-8-resistant pancreatic cancer cells, and underlying mechanisms. TFP or TMX alone did not induce apoptosis of resistant PANC-1 cells, while they dose-dependently enhanced TRA-8-induced apoptosis. TMX treatment enhanced efficacy of TRA-8 therapy on tumorigenesis in vivo. Analysis of TRA-8-induced death-inducing-signaling-complex (DISC) identified recruitment of survival signals, CaM/Src, into DR5-associated DISC, which was inhibited by TMX/TFP. In contrast, TMX/TFP increased TRA-8-induced DISC recruitment/activation of caspase-8. Consistently, caspase-8 inhibition blocked the effects of TFP/TMX on TRA-8-induced apoptosis. Moreover, TFP/TMX induced DR5 expression. With a series of deletion/point mutants, we identified CaM antagonist-responsive region in the putative Sp1-binding domain between −295 to −300 base pairs of DR5 gene. Altogether, we have demonstrated that CaM antagonists enhance TRA-8-induced apoptosis of TRA-8-resistant pancreatic cancer cells by increasing DR5 expression and enhancing recruitment of apoptotic signal while decreasing survival signals in DR5-associated DISC. Our studies support the use of these readily available CaM antagonists combined with TRAIL-activating agents for pancreatic cancer therapy.     

右归丸补肾填精的药理作用

目的:以下丘脑-垂体-性腺轴为基础,探究右归丸对肾阳虚大鼠的药理作用,探讨其补肾填精的作用机制。方法:SD大鼠60只,采用氢化可的松建立肾阳虚模型大鼠,随机分为6组,分别为正常组、模型组、甲基睾酮(0.5 g·kg-1)组、右归丸低、中、高剂量组(0.5,1.0,2.5 g·kg-1),每组10只。造模后连续ig给药30 d,分别于给药第15,30天进行强迫负重游泳实验;第30天,眼球取血,放射免疫分析法检测大鼠血清睾酮(testosterone,T)、雌二醇(estradiol,E2)的含量;采用RT-PCR法检测各组大鼠下丘脑、垂体和靶腺(睾丸)钙调蛋白(Ca M)mRNA的表达。结果:与正常组比,模型组大鼠的负重游泳时间减少(P0.05),明显升高血清中E2的激素水平及降低T的激素水平(P0.05),明显升高下丘脑、垂体、睾丸中Ca M mRNA的表达(P0.05);与模型组比,甲基睾酮组、右归丸低、中、高剂量组可明显提高肾阳虚模型大鼠的负重游泳时长(P0.05),给药20 d后其体能趋于正常;给药20 d后甲基睾酮组、右归丸低、中、高剂量组可明显降低血清中E2的激素水平及升高T的激素水平(P0.05),明显降低下丘脑、垂体、睾丸中Ca M mRNA的表达(P0.05)。结论:右归丸可通过调节机体下丘脑-垂体-性腺轴中钙调蛋白基因表达,改善阳虚大鼠激素水平,逆转肾阳虚状态,具有补肾填精的作用。     

Serotonin inhibits Na+/H+ exchange activity via 5-HT4 receptors and activation of PKC alpha in human intestinal epithelial cells

BACKGROUND & AIMS: Increased serotonin levels have been implicated in the pathophysiology of diarrhea associated with celiac and inflammatory diseases. However, the effects of serotonin on Na+ /H+ exchange (NHE) activity in the human intestine have not been investigated fully. The present studies examined the acute effects of 5-hydroxytryptamine (5-HT) on NHE activity using Caco-2 cells as an in vitro model. METHODS: Caco-2 cells were treated with 5-HT (.1 micromol/L, 1 h) and NHE activity was measured as ethyl-isopropyl-amiloride (EIPA)-sensitive 22Na uptake. The effect of 5-HT receptor-specific agonists and antagonists was examined. The role of signaling intermediates in 5-HT-mediated effects on NHE activity was elucidated using pharmacologic inhibitors and immunoblotting. RESULTS: NHE activity was inhibited significantly (approximately 50%-75%, P < .05) by .1 micromol/L 5-HT via inhibition of maximal velocity (Vmax) without any changes in apparent affinity (Km) for the substrate Na+ . NHE inhibition involved a decrease of both NHE2 and NHE3 activities. Studies using specific inhibitors and agonists showed that the effects of 5-HT were mediated by 5-HT4 receptors. 5-HT-mediated inhibition of NHE activity was dependent on phosphorylation of phospholipase C gamma 1 (PLC gamma 1) via activation of src-kinases. Signaling pathways downstream of PLC gamma 1 involved increase of intracellular Ca 2+ levels and subsequent activation of protein kinase C alpha (PKC alpha). The effects of 5-HT on NHE activity were not cell-line specific because T84 cells also showed NHE inhibition. CONCLUSIONS: A better understanding of the regulation of Na+ absorption by 5-HT offers the potential for providing insights into molecular and cellular mechanisms involved in various diarrheal and inflammatory disorders.     

Raised urinary calmodulin levels in idiopathic myelofibrosis: possible implications for the aetiology of fibrosis

Summary. Platelet growth factors (e.g. PDGF and TGF-β) are thought to be pathogenetically important in the stromal reaction characteristic of idiopathic myelofibrosis (IM). We have investigated a possible pathogenetic role for a further platelet mitogen, calmodulin. Platelets are rich in calmodulin, of which 30–40% is releasable with a time course that differs from α-granule proteins. In IM urinary calmodulin concentrations were 3-fold those of the normals controls. We suggest that an abnormal release of calmodulin may occur from platelets/megakaryocytes in patients with IM, and that calmodulin should be considered, along with other growth factors, in the pathogenesis of marrow fibrosis.     

Platelet calmodulin correlates with platelet turnover

We measured the calmodulin content in platelets in 13 normal persons and in 62 patients with hematological diseases. The level of platelet calmodulin was higher in patients with idiopathic thrombocytopenic purpura (ITP), systemic lupus erythematosus, myeloproliferative disorders, acute leukemia in a recovery phase, aplastic anemia, thrombosis and hypersplenism as compared to the controls. Among the patients with ITP, calmodulin was lower in responders than in nonresponders and those at the initial diagnosis. We also measured the volume, life-span and aggregation of the platelets and demonstrated a significant relationship between the calmodulin level and the platelet volume, and a negative relationship between the calmodulin level and platelet life-span, there was no correlation between the calmodulin level and platelet aggregation. We thus conclude that platelet calmodulin is inversely correlated with platelet turnover.     

Self Reports on Alcohol use and Compliance with Antihypertensive Medication

Adverse effects of alcohol drinking were investigated in 240 hypertensive patients. Perceived interaction between alcohol and antihypertensive medication was reported by 9.9% of patients but the symptoms were rather mild. Except for the fact that the patients who perceived drug-alcohol interaction had higher dia-stolic blood pressure than the rest of the patients there was no evidence that alcohol use decreased compliance with antihypertensive treatment. Most heavy alcohol users believed that they should take their antihypertensive medication while drinking and reported doing so. Indiscriminate emphasis on avoidance of drug-alcohol combination might decrease blood pressure control of these patients.     

Nonfunctional NaV1.1 familial hemiplegic migraine mutant transformed into gain of function by partial rescue of folding defects

Familial hemiplegic migraine (FHM) is a rare subtype of migraine with aura. Mutations causing FHM type 3 have been identified in SCN1A, the gene encoding the Na_v1.1 Na⁺ channel, which is also a major target of epileptogenic mutations and is particularly important for the excitability of GABAergic neurons. However, functional studies of Na_V1.1 FHM mutations have generated controversial results. In particular, it has been shown that the Na_V1.1-L1649Q mutant is nonfunctional when expressed in a human cell line because of impaired plasma membrane expression, similarly to Na_V1.1 mutants that cause severe epilepsy, but we have observed gain-of-function effects for other Na_V1.1 FHM mutants. Here we show that Na_V1.1-L1649Q is nonfunctional because of folding defects that are rescuable by incubation at lower temperatures or coexpression of interacting proteins, and that a partial rescue is sufficient for inducing an overall gain of function because of the modifications in gating properties. Strikingly, when expressed in neurons, the mutant was partially rescued and was a constitutive gain of function. A computational model showed that 35% rescue can be sufficient for inducing gain of function. Interestingly, previously described folding-defective epileptogenic Na_V1.1 mutants show loss of function also when rescued. Our results are consistent with gain of function as the functional effect of Na_V1.1 FHM mutations and hyperexcitability of GABAergic neurons as the pathomechanism of FHM type 3.Epilepsy and migraine are common neurologic disorders that may have pathophysiological links (1–3). Mutations have been identified for some rare types of epilepsy and migraine (1, 4–6), opening a window for investigating their pathogenic mechanisms, which may provide useful information also about more common forms. The Na⁺ channel α subunit Na_V1.1, encoded by the SCN1A gene, is the target of hundreds of epileptogenic mutations (7–9), and of mutations causing familial hemiplegic migraine type 3 (FHM-3), a rare subtype of migraine with aura characterized by hemiplegia during the attacks, which can also be caused by mutations of Ca_V2.1 Ca²⁺ channels and the α2 subunit of the Na⁺/K⁺ ATPase (FHM types 1 and 2) (1, 6). The results of most studies suggest that epileptogenic Na_V1.1 mutations cause variable degrees of loss of function of Na_V1.1, leading to reduced Na⁺ current and excitability in GABAergic neurons, and resulting in decreased inhibition in neuronal networks (10–14). The most severe phenotypes (e.g., Dravet syndrome, an extremely severe epileptic encephalopathy) are in general caused by mutations that induce complete Na_V1.1 loss of function, leading to haploinsufficiency (15). Thus, it has been hypothesized that a more severe loss of function would cause more severe epilepsy (8). Functional studies of Na_V1.1 FHM mutations have generated more confusing results (1). For instance, we have reported gain-of-function effects for the mutant Q1489K causing pure FHM (16), and modulable gain-/loss-of-function effects for the mutant T1174S associated with FHM or mild epilepsy in different branches of the family (17). Overall, our results are consistent with a gain of function of Na_V1.1 as the cause of FHM, which might induce cortical spreading depression (CSD), a probable pathomechanism of migraine, because of hyperexcitability of GABAergic interneurons (16). However, a study has reported loss of function for FHM hNa_V1.1 mutants expressed in the human cell line tsA-201—in particular, complete loss of function for the L1649Q mutant because of lack of cell surface expression (18). L1649Q has been identified in a four-generation family with eight members presenting with FHM, without epilepsy or other neurologic symptoms (19); this is a puzzling result more consistent with a phenotype of severe epilepsy (7, 8). We have found that Na_V1.1 epileptogenic mutations can induce loss of function by causing folding defects (20), which can be partially rescued by incubation of the transfected cells at lower temperatures (≤30 °C) or by molecular interactions (21, 22), as recently confirmed also for other epileptogenic Na_V1.1 mutants (23, 24). We report here that L1649Q is a folding-defective mutant that, when partially rescued, is characterized by an overall gain of function, consistent with our hypothesis of FHM type 3 pathomechanism (16).     

Protein kinases modulate the sensitivity of hippocampal neurons to nitric oxide toxicity and anoxia

Multiple processes lead to neuronal death after ischemia, but the generation of nitric oxide (NO) is a key component in this cascade of events. The mechanisms that regulate the extent of neuronal degeneration during anoxia and NO toxicity are multifactorial. Neuronal death may be modulated by the activity of signal transduction systems that influence the toxicity of NO or its metabolic products such as cGMP. The enzyme responsible for the production of NO, nitric oxide synthase (NOS), is phosphorylated by protein kinase C (PKC), the cAMP-dependent protein kinase (PKA), and the calcium/calmodulin-dependent protein kinase II (CaM-II). We examined in primary cultured hippocampal neurons whether the protein kinases PKC, PKA, CaM-II, and cGMP-dependent protein kinase modified the toxic effects of anoxia and NO. Down-regulation of PKC activity with PMA (1μM) increased hippocampal neuronal survival during anoxia and NO exposure from approximately 22% to 88%. Inhibitors of PKC activity 9H-7, H-8, sphingosine, and staurosporine also were neuroprotective. Down-regulation of PKC activity increased survival during anoxia even in the presence of the NOS inhibitor, N^ω-methyl-L-arginine. Thus, although down-regulation of PKC activity may increase neuronal survival by decreasing NOS activity, it also is likely that PKC contributes to ischemic neuronal death by mechanisms that are independent of NOS. Inhibition of the cGMP-dependent protein kinase activity, but not the activity of the CaM-II also was neuroprotective during NO administration. In contrast to the protective effects of inhibition of PKC and the cGMP-dependent protein kinase, activation rather than inhibition of PKA increased hippocampal neuronal survival during NO exposure. These results indicate that neuronal survival during anoxia and NO exposure is linked to the modulation of PKC, PKA, and cGMP-dependent protein kinase activity but is not dependent on the CaM-II pathway. Understanding the involvement of PKC, PKA, and the cGMP-dependent protein kinase in modulating the effect of neuronal death during ischemia and NO toxicity may help in directing future therapeutic modalities for cerebrovascular disease. © 1993 Wiley-Liss, Inc.