平喘合剂对哮喘豚鼠β受体影响的实验研究

目的 :观察 β受体在平喘合剂治疗哮喘中的作用。方法 :运用放射性配基结合实验方法测定豚鼠肺组织中 β受体Bmax和平衡离解常数 (kd) ;结果 :模型组豚鼠肺组织中 β受体数量比健康对照组明显降低 ,而经平喘合剂、地塞米松组治疗后 ,豚鼠肺组织中 β受体数量显著升高 ,且地塞米松组与平喘合剂组无明显差异。结论 :平喘合剂可升高 β受体含量而治疗哮喘。

TGF-β/Smads信号通路在心肌纤维化发生和治疗中应用前景的研究进展

心肌纤维化(MF)是多种心脏疾病发展到一定阶段的共同病理改变,是心肌重构的主要表现之一。这种病理变化存在于多种心血管疾病中,与心律失常、心力衰竭等疾病密切相关。转化生长因子-β(TGF-β)在MF的发生和发展中起着重要作用。TGF-β/Smads信号通路是TGF-β发挥生物学作用的主要通路,其分子组成与分子调节复杂,现将它在MF发生和治疗中应用前景作一综述。

Effect of Fish Oil on (-Adrenoceptors and the Activity of Adenylate Cyclase on Myocardial Membrane in Rats

Effects of fish oil on β-adrenoceptors as well as the activity of adenylate cyclase (AC) on rat myocardial membrane were investigated.Supplementation with fish oil had no significant effect on basal activity of AC on myocardial membrane whereas it could markedly inhibit the AC activity stimulated by isoproterenol (ISO). Radioligand binding assays showed that supplementation with fish oil had no effect on Bmax and Kd, compared with saline control. However, supplementation with sheep oil could markedly reduce both the Kd and Bmax, compared with saline control. And the Kd of sheep oil group was greatly decreased than that of fish oil group. The results suggested that supplementation with fish oil mainly affected the activation of AC, not β-adrenoceptor itself.

Association of CA Repeat Polymorphism in Estrogen Receptor β Gene with Postmenopausal Osteoporosis in Chinese

Postmenopausal osteoporosis （PMO） is considered a polygenic disease. The estrogen receptor β （ESR2） gene is a candidate mediating the genetic influence on bone mass and the risk of osteoporosis. The aim of this study is to investigate the association of a cytosine-adenine （CA） repeat polymorphism in the fifth intron of the ESR2 gene with PMO in Chinese Han population. The CA repeat polymorphism was genotyped in a case-control study, involving 78 femoral neck PMO patients vs. 122 controls and 108 lumbar spine （L2-4） PMO patients vs. 92 controls. The （CA）n〈22 and （CA）n≥22 alleles were designated short （S） and long （L）, respectively. ESR2 genotype was categorically defined as SS （2 S alleles）, SL （having the mixed S and L alleles）, and LL （2 L alleles）. At both the femoral neck and the L2-4 region, LL genotype and L allele frequencies of the PMO group were significantly higher than those of the control group （P〈0.01）. The subjects with the SL, the LL, and the combined SL and LL genotype had a significant increased risk of PMO when compared with those with the SS genotype （P〈0.05）. After adjustments for age, years since menopause, menopausal age, and body mass index, logistic regression analysis showed that the subjects with the combined SL and LL genotype had increased risk of PMO when compared with those with the SS genotype both at the femoral neck （adjusted OR 4.923, 95% CI 1.986-12.203 , P=0.001） and the L2-4 （adjusted OR 2.267, 95% CI 1.121-4.598, P=0.023）. This extensive association study has identified the ESR2 CA repeat polymorphism to be independently associated with PMO at the femoral neck and the L2-4 in Chinese Han population. The data also suggested that the presence of the L allele may dominantly increase the risk of PMO at the two regions.

Expression patterns of transforming growth factor-beta and its receptors in gastric mucosa of patients with refractory gastric ulcer

AIM: Transforming growth factor-β (TGF-β) plays a regulatory role in tissue repair. In a previous study, we found that TGF-β and its receptors were expressed in gastric mucosa of patients with well-healed gastric ulcers, as demonstrated by immunohistochemistry. To further characterize the role of TGF-β and its receptors in repairing gastric ulcers, we investigated the expression patterns of TGF-β and its receptors in gastric mucosa by in situ hybridization and reverse transcriptase-polymerase chain reaction (RT-PCR).METHODS: Seventy-four patients with endoscopically proven gastric ulcers were eligible for participation in this study. All patients had routine biopsies on initial endoscopy and were then treated for 12 wk with an H2 blocker. Repeat endoscopy was then performed. There were 8 patients with poorly healed ulcers, and biopsies were taken from the margin of the residual ulcers. These tissue samples, along with biopsy of gastric mucosa near the original ulcers from 8 randomly selected patients with well-healed ulcers were examined for TGF-β and TGF-β receptor Ⅱ mRNA by RT-PCR and in situ hybridization, as well as immunohistochemistry.RESULTS: TGF-β and TGF-β receptor Ⅱ were strongly expressed in tissues from patients with well-healed ulcers.Four of the 8 patients with poor healing had low or absent expression of TGF-β or TGF-β receptor Ⅱ mRNA. All cases positive by RT-PCR assay were confirmed by in situ hybridization as well as immunohistochemistry.CONCLUSION: It is suggested that TGF-β and its receptors are important for gastric ulcer healing. These results may have implications for further investigation of the healing process and in predicting response to therapy.

Effect of Fish Oil on Left Ventricular Function in Anes-thetized Rats

The effect of fish oil on the basal left ventricular function and changes of left ventricular function induced by isoproterenol(ISO)were demonstrated in our study. The detennina-tion of cardiac perfonnance in vivo showed that supplementation with fish oil(EPA and DHA,70%,1.4 ml / kg) had no significant effect on basal cardiac perfonnance,while it could significantly inhibit changes of+ dp / dt_(max),V_(pm) and HR induced by ISO(0.4μg/ kg,4.0μg/ kg,40μg/ kg)intrave-nously.The results suggested that supplementation with fish oil perhaps affected the function of β-adrenoceptors on rat myocardial membrane.

Inappropriate use of digoxin in patients presenting with digoxin toxicity

Background Digoxin remains widely used today despite its narrow therapeutic index and toxicity. The objective of this study was to investigate the percentage of inappropriate use of digoxin and long-term outcomes of elderly patients hospitalized for digoxin toxicity. Methods The study included 99 consecutive patients hospitalized for digoxin toxicity. The other study criteria for the inappropriate use of digoxin was regarded if participants having depressed left ventricular systolic function （ejection fraction 〈 45%） who were not on optimal medical therapy including beta-blocker and angiotensin-converting-enzyme inhibitor therapy or if participants having permanent AF who were not on optimal beta-blocker therapy. Results Appropriate digoxin usage was confirmed in 33 of patients in spite of its narrow therapeutic index. A total of 16 of 99 patients died, with a mean follow-up time of 22.1 ± 10.3 months. Conclusions Contrary to popular belief, the rate of inappropriate digoxin usage remains high. On account of its narrow therapeutic index and toxicity, digoxin should be used more carefully according to the current evidence and guidelines.

Effects of gastrin 17 on β-catenin/Tcf-4 pathway in Colo320WT colon cancer cells

AIM： To explore the effect of gastrin 17 （G17） on β-catenin/T cell factor-4 （Tcf-4） signaling in colonic cancer cell line Colo320WT. METHODS： The pCR3.1/GR plasmid, which expresses gastrin receptor, cholecystokinin-2 receptor （CCK-2R）, was transfected into a colonic cancer cell line Colo320 by Lipofectamine ^TM 2000 and the stably expressing CCK-2R clones were screened by G418. The expression levels of gastrin receptor in the Colo320 and the transfected Colo320WT cell line were assayed by RTPCR. Colo320WT cells were treated with G17 in a time-dependent manner （0, 1, 6, 12, 24 and 48 h）, then with L365,260 （Gastrin17 receptor blocker） for 30 rain, and with G17 again for 12 h or L365,260 for 12 h. Expression levels of β-catenin in a TX-100 soluble fraction and TX-100 insoluble fraction of Colo320WT cells treated with G17 were detected by co-immuniprecipation and Western blot. Immunocytochemistry was used to examine the distribution of β-catenin in CoLoWT320 cells. Expression levels of c-myc and cyclin D1 in Colo320WT cells treated with G17 were assayed by Western blot. RESULTS： Expression levels of β-catenin in the TX-100 solution fraction decreased apparently in a time- dependent fashion and reached the highest level after G17 treatment for 12 h, while expression levels of β-catenin in the TX-100 insoluble fraction were just on the contrary. Immunocytochemistry showed that β-catenin was translocated from the cell membranes into the cytoplasm and nucleus under G17 treatment. Expression levels of c-myc and cyclin D1 in the G17- treated Colo320WT cells were markedly higher compared to the untreated Colo320WT cells. In addition, the aforementioned G17-stimulated responses were blocked by L365,260.CONCLUSION： Gastrin17 activates β-catenin/Tcf-4 signaling in Colo320WT cells, thereby leading to over- expression of c-myc and cyclin D1.

Association between estrogen receptor β gene Rsa1 polymorphism and depressive disorder in peri-menopausal and menopausal women

Objective: To investigate estrogen receptor β (ERβ) gene Rsa1 polymorphism and concentration of estrogen, FSH and LH in serum in peri-menopausal and menopausal women with depressive disorder. Methods: Seventy-four peri-menopausal and menopausal women with depressive disorder met ICD-10 and CCMD-3 assessment criteria for depressive disorder were recruited. ERβ gene Rsa1 polymorphism was analyzed with PCR-RFLP. Serum levels of estrogen, FSH and LH were measured by magnetism-ELISA. Results: The respective frequency of ERβ gene Rsa1 polymorphism was no significant difference between women with depressive disorder and the healthy women (χ 2=1.106,P>0.05). The serum level of estrogen was lower in women with depressive disorder than in the healthy women (P<0.05). No difference was found for FSH and LH between two groups. Conclusion: ERβ gene Rsa1 polymorphism may be not associated with depressive disorder in the peri-menopausal and menopausal women. The serum level of estrogen is associated with depressive disorder in the peri-menopausal and menopausal women.

TGF-β receptors in mouse ES-5 cells and their differentiated derivatives

By radioreceptor binding studies with iodinated TGF-β1, it has been shown that an undifferentiated ES-5 cell expresses approximately 3270 receptors with a dissociation constant Kd=130pM, but after the induction of differenti-ation by retinoic acid and dBcAMP, the receptor number of a differentiated RA-ES-5 cell was increased about 80% and the Kd was also increased to 370 pM. Furthermore,more direct evidence supporting the expression of TGF-βtype Ⅰand type Ⅱ receptors in both ES-5 and RA-ES-5 cells has come from dot blot hybridization of cellular mRNA with cDNA probes for type Ⅰ and type Ⅱ recep-tors. Meanwhile, mRNA expression level of types Ⅰ and Ⅱreceptors in RA-ES-5 cells were higher than that in ES-5 cells. Down regulation of TGF-β receptors with a signifi-cant decrease in the rate of cell proliferation in both cells, was found by employing a pretreatment with neutralizing antibody to TGF-β1. The possible role of receptors for TGF-β in cen differentiation is discussed here.

Hypertension in the elderly： insights from recent research

Hypertension is a leading cause of mortality and morbidity around the world and,prevalence of hypertension is increasing with aging.Hypertension in the elderly is associated with increased occurrence rates of sodium sensitivity,isolated systolic hypertension,and ＇white coat effect＇.Arterial stiffness and endothelial dysfunction also increase with age.These factors should be considered in selecting antihypertensive therapy.The prime objective of this therapy is to prevent stroke.The fmdings of controlled trials show that there should be no cut-off age for treatment.A holistic program for controlling cardiovascular risks should be fully discussed with the patient,including evaluation to exclude underlying causes of secondary hypertension,and implementation of lifestyle measures.The choice of antihypertensive drug therapy is influenced by concomitant disease and previous medication history,but will typically include a thiazide diuretic as the first-line agent;to this will be added an angiotensin inhibitor and/or a calcium channel blocker.Beta blockers are not generally recommended,in part because they do not combat the effects of increased arterial stiffness.The hypertension-hypoten-sion syndrome requires case-specific management.Drug-resistant hypertension is important to differentiate from faulty compliance with medication.Patients resistant to the third-line drug therapy may benefit from treatment with extended-release isosorbide mononitrate.A trial of spironolactone may also be worthwhile.

Comparison of cleavage activity in vitro between two ribozymes targeted against different sites of PDGF receptor β subunit

Objective: To compare the cleavage activity of ribozymes directed against 2 sites of PDGF receptorP subunit cDNA gene in vitro. Methods: The 608 bp fragment of PDGF receptor β subunit cDNA was clonedinto T-vector under the control of T7 promoter, named pPDGFR-β. Two ribozymes were designed to cleavethe CUU sequence at codon 45 and codon 252 of PDGF receptor β subunit mRNA respectively. These 2 ham-merhead ribozyme genes were cloned into vector PI. 5 between 5' -cis ribozyme and 3' -cis ribozyme to gener-ate the plasmids of pRZ1 and pRZ2. The pPDGFR-β, pRZl and pRZ2 were linearized and then transcribedwith T7 promoter in vitro. Results: The RZ1 showed high cleavage activity in vitro, but the RZ2 showed nocleavage activity under the same condition. Conclusion: The cleavage site selection is an important factor in-fluencing the cleavage activities of ribozymes.

OVER-EXPRESSION OF A TRUNCATED TYPE I TGF-P RECEPTOR IN NORMAL DERMAL FIBROBLASTS DECREASES TGF-β1 AUTOPRODUCTION

Objective To determine over-expression of a truncated type ⅡTGF-β receptor in down-regulating TGF-β1 auto production in normal dermal fibroblasts. Methods In vitro cultured dermal fibroblasts were treated with rhTGF-β1 (5ng/ml) or recombinant adenovirus containing α truncated type Ⅱ TGF-β receptor gene (50 pfu/cell). Their effects on regulating gene expression of TGF-β1 were observed with Northern Blot. Results rh TGF-β1 up-regulated the gene expression of TGF-β1, (34 %-150%) and type Ⅰ pro-collagen( 13 %- 190%). Overexpression of a truncated receptor Ⅱ decreased the gene expression of TGF-β1 (53%-66%). Conclusion Over-expression of the truncated TGF-β receptor Ⅱdown-regulated TGF-β1 autoproduction via blocking signal transduction of TGF-β. This study may provide a new strategy for scar gene therapy.

Structural Dynamics of Amyloid β Peptide Binding to Acetylcholine Receptor and Virtual Screening for Effective Inhibitors

The interaction between Amyloid β(Aβ) peptide and acetylcholine receptor is the key for our understanding of how Aβ fragments block the ion channels within the synapses and thus induce Alzheimer’s disease.Here,molecular docking and molecular dynamics(MD)simulations were performed for the structural dynamics of the docking complex consisting of Aβ and α7-n ACh R(α7 nicotinic acetylcholine receptor),and the inter-molecular interactions between ligand and receptor were revealed.The results show that Aβ_(25-35) is bound toα7-n ACh R through hydrogen bonds and complementary shape,and the Aβ_(25-35) fragments would easily assemble in the ion channel of α7-n ACh R,then block the ion transfer process and induce neuronal apoptosis.The simulated amide-I band of Aβ_(25-35) in the complex is located at 1650.5 cm^(-1),indicating the backbone of Aβ_(25-35) tends to present random coil conformation,which is consistent with the result obtained from cluster analysis.Currently existing drugs were used as templates for virtual screening,eight new drugs were designed and semi-flexible docking was performed for their performance.The results show that,the interactions between new drugs and α7-n ACh R are strong enough to inhibit the aggregation of Aβ_(25-35) fragments in the ion channel,and also be of great potential in the treatment of Alzheimer’s disease.

Retinoic acid receptor β is required for anti-activator protein-1 activity by retinoic acid in gastric cancer cells

Objective To investigate the role of retinoic acid receptor β (RARβ) in mediating inhibitory effect of all-trans retinoic acid (ATRA) on activator protein-1 (AP-1) activity in gastric cancer cells. Methods Transient transfection and chloramphenicol acetyltransferase (CAT) assay, Northern blot, gene transfection, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, and anchorage-independent growth assay were used.Results Transient transfection of RARβ expression vector into MKN-45 cells resulted in the RARβ concentration-dependent repression of AP-1 activity induced by 12-o-tetradecanoylphorbol-13-acetate (TPA), regardless of the presence of ATRA. When the c-jun and c-fos expression vectors were cotransfected with the RARβ expression vector into MKN-45 cells, AP-1 activity was also obviously repressed. The inhibitory effect, again, was RARβ-concentration-dependent. The stable transfection of the RARβ gene into MKN-45 cells led to cell growth inhibition and colony formation inhibition by ATRA. Furthermore, Cotransfection of both RARβ/DNA binding domain (DBD) and reporter gene could not alter AP-1 activity, even in the presence of ATRA. However, when the cotransfection was substituted with the RARβ/ligand binding domain (LBD), the inhibition was significantly enhanced by ATRA. Conclusion RARβ might be required for anti-AP-1 activity, and contribute to growth inhibition of gastric cancer cells by ATRA.

Role of β-adrenoceptor at different stages of bronchial asthma

Objective To investigate the changes of β-adrenergic receptor (βAR) in peripheral lymphocytes and β2AR mRNA levels at different stages of bronchial asthma. Methods β2AR density and β2AR mRNA level in peripheral lymphocytes, cAMP and cGMP levels in blood plasma were estimated by radioligand binding assay, radioimmunoassay and RT-PCR.Results (1) Maximum bound volume (Bmax) and equilibrium dissociation constant (Kd) of β2AR of lymphocyte in asthma patients at remission stage were markedly higher than that in normal subjects, while cAMP levels in blood plasma showed no difference. Bmax of β2AR and cAMP levels in asthma patients at acute exacerbation stage were significantly lower than that in normal subjects, and Kds between these two groups were not much different. (2) Expression of β2ARmRNA in peripheral lymphocytes of asthmatics at remission stage was not significantly different compared with that in normals. Conclusions Amount and function of βAR and β2ARmRNA levels are related to asthmatic conditions. Changes of βAR and β2ARmRNA in asthma might rather be a pathological change accompanied by the course of the disease than a primary defect.

Recent advances in the management of variceal bleeding

Acute haemorrhage from ruptured gastroesophageal varices is perhaps the most serious consequence of uncontrolled portal hypertension in cirrhotic patients.It represents a medical emergency and is associated with a high morbidity and mortality.In those who survive the initial bleeding event,the risks of further bleeding and other decompensated events remain high.The past 30 years have seen a slow evolution of management strategies that have greatly improved the chances of surviving a variceal haemorrhage.Liver cirrhosis is a multi-staged pathological process and we are moving away from a one-size-fits-all therapeutic approach.Instead there is an increasing recognition that a more nuanced approach will yield optimal survival for patients.This approach seeks to risk stratify patients according to their disease stage.The exact type and timing of treatment offered can then be varied to suit individual patients.At the same time,the toolbox of available therapy is expanding and there is a continual stream of emerging evidence to support the use of endoscopic and pharmacological therapies.In this review,we present a summary of the treatment options for a variety of different clinical scenarios and for when there is failure to control bleeding.We have conducted a detailed literature review and presented up-to-date evidence from either primary randomized-controlled trials or meta-analyses that support current treatment algorithms.

Super-resolution imaging and tracking of TGF-β receptor II on living cells

Single-particle tracking photoactivated local- ization microscopy （sptPALM） has recently emerged as a powerful tool for high-density imaging and tracking of individual molecules in living cells. In this work, we have monitored and compared the diffusion dynamics of TGF-β type II receptor （TβRII） at high expression level using both traditional single-particle tracking （SPT） and sptPALM. The ligand-induced aggregation of TβRII oligomers was further indicated by sptPALM. Due to the capacity of distinguishing and tracking single molecules within diffraction limit, sptPALM outperforms traditional SPT by providing more accurate biophysical information,

Inhibition of P2X receptor-mediated inward current by protein kinase C in small-diameter dorsal root ganglion neurons of adult rats

Objective The aim of the present study is to verify the ATP-induced varied responses in isolated dorsal root ganglion （DRG） neurons of the adult rat, and investigate the modulatory effects of specific P2X receptor agonist β,γ-me-ATP and protein kinase C （PKC） on P2X receptor-mediated inward current in DRG neurons. Methods Whole cell patch-clamp was employed to record the currents on acutely isolated DRG neurons in the adult rats. Results β,γ-me-ATE similar as ATE evoked 2 distinct subtypes of P2X receptor-mediated inward currents in a dose-dependent manner in DRG neurons. Activation of PKC by phorbol 12,13-dibutyrate （PDBu） significantly inhibited both subtypes of inward currents mediated by P2X receptors in a dose-dependent manner. Conclusion Activation of PKC negatively modulated the P2X receptor-mediated currents in rat DRG neurons, which may be of benefit to preventing the over-excitation of nociceptor under inflammatory or neuropathic conditions.