氧化苯胂对大鼠心室肌细胞L型Ca2+电流的影响

目的 :探讨氧化苯胂 （PAO） ,一种膜可通透的酪氨酸磷酸酶抑制剂 ,对大鼠心室肌细胞 L型 Ca2 +电流 （ICa,L）的影响。方法 :采用全细胞膜片钳技术记录大鼠心室肌细胞 ICa,L。结果 :1PAO对基础 ICa,L及β-肾上腺素受体激动剂异丙肾上腺素 （Iso）激发的 ICa,L有抑制作用 ;2 PAO对腺苷酸环化酶激动剂 forskolin激发的 ICa,L亦有抑制作用 ;3电极内液加入 1.5 mm ol/ L矾酸钠不能消除 PAO的作用 ;4PAO对 ICa,L的抑制作用可被二硫代苏糖醇反转。结论 :PAO抑制 ICa,L的作用与 c AMP- PKA-磷酸化途径和酪氨酸磷酸酶无关 ,可能与其使 L 型 Ca2 +通道蛋白上巯基氧化有关。     

大蒜素对自发性高血压大鼠肠系膜动脉平滑肌细胞钙电流的作用

目的:观察大蒜素(Gar)对自发性高血压大鼠(SHR)肠系膜动脉平滑肌细胞L-型钙电流(LCa,L)的影响。方法:利用双酶-两步法消化得到单个大鼠肠系膜动脉血管平滑肌细胞,用全细胞膜片钳记录钙电流。在细胞池中灌流含Gar的细胞外液,观察药物对LCa,L的作用和门控机制及门控动力学参数的改变。结果:1Gar对ICa,L的抑制效应呈浓度依赖性和电压依赖性特征。刺激电位0 mV时,200μmol/L Gar可使ICa,L峰值密度由(-8.4±0.4)pA/pF降低为(-6.1±0.3)pA/pF;2药物可使ICa,L半激活电压V1/2右移,半失活电压左移及失活后恢复动力学减慢等环节可减少通道的开放和重复开放,从而减少ICa,L峰值密度和窗口电流。结论:Gar可能通过减少细胞的钙电流发挥降压效应。     

急性缺血对单个家兔窦房结起搏细胞钙通道的影响

目的:观察急性缺血对窦房结(SAN)起搏细胞(PCs)钙通道电流的影响,探讨急性缺血诱导自发性电活动改变的离子机制.方法:灌流缺血样台氏液(低pH、无葡萄糖以及100% N2饱和)模拟缺血;酶消化法分离家兔SAN PCs,采用穿孔膜片钳技术,记录电压依赖性的钙电流.结果:缺血可显著增大L-型钙电流(ICa,L)密度,并增大最大膜电导,使稳态-失活曲线右移,而对激活曲线无明显影响;然而缺血可明显抑制T-型钙电流(ICa,T).结论:急性缺血通过增大最大膜电导以及抑制通道的失活从而增强SAN PCs的ICa,L;急性缺血后ICa,L的密度增大以及ICa,T的密度减小可能是急性缺血诱导的自发性电活动改变的主要离子机制.     

卡维地洛对大鼠心室肌细胞L型钙电流的影响

目的研究卡维地洛对大鼠心室肌细胞L型钙电流(ICa,L)的影响,探讨卡维地洛在离子通道水平的药理机制。方法用急性酶解法获得大鼠单个心室肌细胞,用标准全细胞膜片钳技术记录ICa,L,观察不同浓度卡维地洛对ICa,L的影响。结果①卡维地洛呈浓度依赖性抑制ICa,L,1μmol/L卡维地洛能使心肌细胞ICa,L电流-电压关系曲线明显上移,峰电流密度减少(7.80±0.65pA/pFvs4.89±0.52pA/pF,n=10,P<0.05),但激活电位、峰电位和翻转电位无明显改变。②卡维地洛能使ICa,L失活曲线明显左移,但对ICa,L激活和复活曲线无明显影响。③0.1μmol/L卡维地洛对钙电流无明显影响,但可以明显阻断异丙肾上腺素增加钙电流效应。同时,卡维地洛对钙电流的抑制效应不能被哌唑嗪和普奈洛尔阻断。结论卡维地洛呈浓度依赖性地抑制心室肌细胞L型钙通道。     

丹酚酸B对大鼠心室肌细胞瞬时外向钾电流和L型钙电流的阻滞作用

目的研究从丹参中分离提取的药物单体——丹酚酸B对大鼠心肌细胞上的瞬时外向钾电流(Ito)、内向整流钾电流(IK1)和L型钙电流(ICa,L)的电生理学作用。方法用酶解法分离大鼠心室肌细胞,全细胞膜片钳技术记录Ito、IK1和ICa,L。每个细胞采用加药前后自身对照,用含100μmol/L丹酚酸B的细胞外液灌流心室肌细胞,记录加药前、后的电流,所有数据均在细胞破膜后20min内完成。结果 100μmol/L的丹酚酸B对Ito和ICa,L具有抑制作用,使Ito和ICa,L最大激活峰值电流密度下降,电流密度-电压曲线下移;且丹酚酸B主要抑制Ito的快速电流成分Itof,而对Ito的缓慢电流成分Itos无明显作用。在60mV测试电压下,Itof的最大激活峰值电流密度从23.51±3.29pA/pF降为16.85±2.36pA/pF,抑制率为28.31%±10.6%(n=8,P0.05)。在-10mV测试电压下,100μmol/L丹酚酸B作用后ICa,L的最大激活峰值电流密度从-8.66±-2.40pA/pF降为-5.91±-2.14pA/pF,抑制率为31.84%±10.23%(n=11,P0.05)。丹酚酸B使Ito通道失活后的恢复减慢,但不改变ICa,L的通道动力学。丹酚酸B对IK1无显著作用。结论丹酚酸B对Ito和ICa,L具有阻滞作用,而对IK1无显著作用。     

渗透压对大鼠心室肌细胞L型Ca2+电流的影响

目的 :观察细胞胞外渗透压的改变对大鼠心室肌 L型 Ca2 +（ICa,L）电流的影响。方法 :采用全细胞膜片钳技术记录大鼠心室肌细胞 ICa,L。结果 :细胞外的渗透压由 3 10 m Osm / kg H2 O降低至 2 2 0 m Osm/ kg H2 O可使 ICa,L的 rundown明显变慢 ,电流大小无统计学意义上的差异 ;而当其中细胞外的渗透压由 3 10 m Osm/ kg H2 O升高至 410m Osm/ kg H2 O时可使 ICa,L减小 （5 1.4± 7.9） % （n=4,P<0 .0 1）。结论 :细胞外渗透压变化对大鼠心室肌基础 ICa,L有明显影响     

巨噬细胞移动抑制因子对HL-1细胞T型钙电流的调控

目的 观察巨噬细胞移动抑制因子（macrophage migration inhibitory factor,MIF）对心房肌细胞T型钙电流（T-type calcium channel current,ICa,T）的调控.方法 使用全细胞膜片钳和分子生物分析方法检测心房肌细胞ICa,T的表达.结果 在体外培养的心房肌细胞株（HL-1细胞）中,小鼠重组MIF（20、40 nmol/L,24 h）可明显抑制ICa,T的峰值电流,与对照组比较,差异均有统计学意义[峰值内向电流：（-17.5±2.9）pA/pF vs.（-27.9±3.4） pA/pF,P＜0.05;（-11.3±1.7）pA/pF vs.（-27.9±3.4）pA/pF,P＜0.01];并可损伤电压依赖的ICa,T激活,使T型钙通道α1G和α1H亚单位mRNA表达下调.而Src非特异性抑制剂genistein和特异性抑制剂PP1可逆转40 nmol/L MIF所致的ICa,T下调[genistein：（-11.3±1.7）pA/pF vs.（-16.1±0.8）,P＜0.05;PPI：（-11.3±1.7）pA/pFvs.（-19.0±3.2）pA/pF,P＜0.05].结论 MIF可能通过影响ICa,T参与心房颤动的病理过程,Src可能参与该信号转导途径.     

西洛他唑对大鼠右心室肌细胞离子通道的影响

目的：观察西洛他唑对大鼠右心室肌细胞离子通道的影响,探讨西洛他唑预防Brugada综合征室性心律失常发生的离子通道机制。
　　方法：本研究包括两部分实验：①灌流实验,分为1、2、5、50μmol/L西洛他唑组,每组记录的细胞数分别为9、5、3、7个。分别观察每组给药前后瞬间外向钾电流（Ito）电流密度的变化,并观察四组间用药前后Ito电流密度变化的差异;②口服药物实验,分为空白1组、实验1组、空白2组、实验2组,每组选用的大鼠数分别为7、5、8、6只,分别观察实验组与空白组Ito、L-型钙电流（ICa,L）电流密度的差异。
　　结果：灌流实验结果：①在1、2、5、50μmol/L西洛他唑各组中,细胞灌流药物后Ito电流密度均降低,在自指令电压+60 mV时,各组用药前后的Ito电流密度差异有统计学意义（P均＜0.05）。②在各指令电压下时,不同浓度西洛他唑灌流液灌流细胞后Ito电流密度减少率,四组间差异均无统计学意义（P均>0.05）。口服药物实验结果：①在自指令电压-50 mV到最大+60 mV,实验1组Ito电流密度较空白1组无明显变化,差异无统计学意义（P>0.05）;②在自指令电压为+10 mV,空白2组ICa,L电流密度较实验2组略高,但差异无统计学意义（P>0.05）。
　　结论：1、2、5、50μmol/L西洛他唑灌流液直接作用于大鼠右心室肌细胞,均能明显的抑制Ito,但西洛他唑1~50μmol/L范围内对Ito的抑制程度没有差异。西洛他唑可能具有抑制Brugada综合征心律失常发生的作用。     

黄芪总黄酮对急性心肌梗死大鼠心室肌细胞L-型钙电流及钠电流的作用

目的研究黄芪总黄酮（TFA）对急性心肌梗死（Am）大鼠心室肌细胞L-型钙电流（L—ICa）及钠电流（INa）的作用。方法设正常对照组、AMI组及TFA实验组。大鼠开胸左前降支结扎造成AMI,开胸前5min实验组大鼠舌静脉注射剂量为20mg／kg的TFA溶液50ul。用胶原酶酶解法急性分离AMI模型大鼠心室肌细胞,采用全细胞膜片钳记录技术记录左前降支供血区心外膜细胞的L—ICa及INa的作用。结果①应用TFA（20mg／kg）后,L—ICa从（0．313±0．14）nA增加到（0．402±0．27）nA,差异有统计学意义（P〈0．01,n=6）。②应用TFA（20mg／kg）后与对照组比较,峰值从（-8．43±2,03）nA下降到（-6．37±1．58）nA,差异有统计学意义（P〈0．01,n=6）。结论TFA可以增加AMI大鼠心室肌细胞L—ICa的幅值,TFA可显著降低AMI大鼠心室肌细胞INa的幅值。     

Ghrelin对大鼠心室肌细胞L型钙电流的影响

目的：研究一种具有生长激素释放活性的脑肠肽（Ghrelin）对大鼠心室肌细胞L型钙电流的影响。方法：采用酶解消化法获得大鼠单个心室肌细胞,通过全细胞膜片钳技术研究不同浓度（10 nmol/L、100 nmol/L及1μmol/L） Ghrelin对L型钙电流的影响。结果：10 nmol/L、100 nmol/L及1μmol/L Ghrelin依次抑制大鼠心室肌细胞L型钙电流峰电位,抑制率分别为：8.95%±2.13%、31.18%±4.78%及64.63%±8.57%,（P<0.05）;I-V曲线上移,通道半数失活电压从（-1.34±1.9） mV分别降至（-8.04±1.32）mV、（9.76±1.17）mV及（-11.81±0.73）mV（P<0.05）,并延长失活后恢复时间由给药前τ值63.23±9.32,分别增至98.95±10.74、109.56±13.42和127.39±16.13,差异有统计学意义（P<0.05）。结论：Ghrelin通过加快L型钙电流的失活及延长失活后恢复时间,具有浓度依赖性地抑制L型钙电流。     

The immunoneuroendocrine role of melatonin

Abstract: A tight, physiological link between the pineal gland and the immune system is emerging from a series of experimental studies. This link might reflect the evolutionary connection between self-recognition and reproduction. Pinealectomy or other experimental methods which inhibit melatonin synthesis and secretion induce a state of immunodepression which is counteracted by melatonin. In general, melatonin seems to have an immunoenhancing effect that is particularly apparent in immunodepressive states. The negative effect of acute stress or immunosuppressive pharmacological treatments on various immune parameters are counteracted by melatonin. It seems important to note that one of the main targets of melatonin is the thymus, i.e., the central organ of the immune system. The clinical use of melatonin as an immunotherapeutic agent seems promising in primary and secondary immunodeficiencies as well as in cancer immunotherapy. The immunoenhancing action of melatonin seems to be mediated by T-helper cell-derived opioid peptides as well as by lymphokines and, perhaps, by pituitary hormones. Melatonin-induced-immuno-opioids (MHO) and lymphokines imply the presence of specific binding sites or melatonin receptors on cells of the immune system. On the other hand, lymphokines such as -γ-interferon and interleukin-2 as well as thymic hormones can modulate the synthesis of melatonin in the pineal gland. The pineal gland might thus be viewed as the crux of a sophisticated immunoneuroendocrine network which functions as an unconscious, diffuse sensory organ.     

Changes in connexin43, the gap junction protein of astrocytes, during development of the rat pineal gland

Abstract: The abundance of gap junctions between rat pineal astrocytes formed by connexin43 (Cx43) was studied during development. Levels and distribution of Cx43 were measured by immunoblotting and indirect immunofluorescence, respectively. The amount of Cx43 in cells located within the gland was low until about the 7th postnatal day and increased to adult values between the 14th and 21st days postpartum. Although astrocytes, recognized by their vimentin immunoreactivity, were scarce before birth, they were abundant by the 7th postnatal day suggesting that the low levels of Cx43 found at this age corresponded to a low expression of this protein. Localization of the immunoreactivity to Cx43 and vimentin showed a close correlation, indicating that mature or immature pineal astrocytes form gap junctions made of Cx43. Since Cx43 levels attained their adult values at about the time the innervation and the functional state of the gland reached maturity (2–3 weeks after birth), it is proposed that astrocyte gap junctions are involved in the function of the adult rat pineal gland.     

Conservative management of perforated duodenal diverticulum： A case report and review of the literature

Duodenal diverticula are a relatively common condition. They are asymptomatic, unless they become complicated, with perforation being the rarest but most severe complication. Surgical treatment is the most frequently performed approach. We report the case of a patient with a perforated duodenal diverticulum, which was diagnosed early and treated conservatively with antibiotics and percutaneous drainage of secondary retroperitoneal abscesses. We suggest this method could be an acceptable option for the management of similar cases, provided that the patient is in good general condition and without septic signs.     

Response of rat pineal melatonin to calcium, magnesium, and lithium is circadian stage dependent

Abstract: Herein we documented the response of pineal melatonin production to electrolytes known to be effective on pineal function in view of a possible circadian stage dependence. We studied the release of melatonin by perifused rat pineal glands at 2 different circadian stages corresponding to the middle of the light and dark periods, i.e., respectively, 7 and 19 HALO (Hours After Light Onset, L:D = 12:12). The initial efflux rates were, as expected, much higher in the perifusates of glands removed from rats sacrificed during the dark phase than of those removed during the light phase. After 3 hr of perifusion, melatonin release reached similar levels which were found constant up to the 8th hr of perifusion, whatever the circadian stage. Perifusion of the glands with physiological concentrations for the rat of calcium (5.2 mmol/1) and magnesium (1.34 mmol/1) resulted in a stimulatory effect on the pineal glands removed from rats sacrificed in the middle of the dark period (19 HALO), whereas no effects were observed on the pineal glands removed from rats sacrificed during the light (7 HALO). Lithium (0.28 and 0.55 mmol/1) was ineffective on melatonin release in pineal glands removed 7 and 19 HALO. Our results show differences in the initial efflux rates of melatonin and in the response of perifused pineal glands to calcium and magnesium according to the circadian stage.     

Presence of immunoreactive growth hormone and prolactin in the ovine pineal gland

Abstract: The use of antisera raised against bovine growth hormone (GH) and ovine prolactin (PRL) enabled the detection of related immunoreactive (ir) sequences of proteins in ovine pineal tissue. The isolation of PRL-like ir-material was accomplished using a 0.25 M ammonium sulphate (pH 5.5) extraction followed by ethanol precipitation, whereas the resulting 2.0 M ammonium sulphate (pH 7.0) precipitate contained a GH-like immunoreactivity. Gel chromatography of the GH-like immunoreactivity (Sephadex G-100) indicated the presence of several GH-like fragments ranging in the M_r range of 7,000 to 55,000. Analyses of the PRL-like ir-material found in pineal tissue on HPLC using a TSK 545-DEAE column led to the resolution into a single peak of immunoreactivity. A single peak of activity was also observed following chromatofocusing and hydrophobic interaction chromatography of the ir-peak from the TSK 545-DEAE column. The PRL-like ir-material inhibited the binding of [¹²⁵I]ovine PRL-S14 to anti-ovine PRL antibodies without showing an affinity for binding to anti-rat PRL or anti-bovine GH antibodies. Scatchard analysis of the binding of pineal PRL-like ir-material and pituitary ovine PRL-S14 to liver membranes from day-20 pregnant rats revealed similar affinity constants (K_a of 4.7 ± 0.2 × 10⁹ M^-1). In addition, the replication of Nb 2 Node rat lymphoma cells was stimulated by pineal PRL-like ir-material, an effect known to be specific for lactogenic hormones. The pineal PRL-like immunoreactivity appeared on sodium dodecyl sulfate polyacrylamide gels as a single major band of M_r 24,000. The functional status of PRL-and GH-like ir-material in the ovine pineal remains to be determined, but evidence is presented that the overall protein synthesis rate of the rat pineal responded to circulating concentrations of PRL.     

Microbiology of human immunodeficiency virus anorectal disease

PURPOSE: Individuals who are seropositive for the human immunodeficiency virus are at high risk for opportunistic infection and anorectal disorders. Little prospective information is available regarding anorectal pathogens in these patients. METHODS: One hundred sixty-three HIV-seropositive patients presented to the colorectal clinic between 1989 and 1992. Forty-seven (29 percent) patients were thought to have an infectious process and were prospectively studied using a standardized multiculture protocol. RESULTS: Mean age was 33 (range, 19–59) years. All were male; high-risk behavior accounted for 87 percent of HIV transmissions. Presenting complaints included anorectal pain (79 percent), pus per anum (28 percent), and blood per anum (26 percent). Examination revealed perianal tenderness (60 percent), condyloma (38 percent), perianal ulcers (38 percent), and anal fissures (34 percent). Sixty-six sets of cultures were performed; 28 patients had one set, 15 had two sets, and 4 had three sets. Thirty-two of these 47 patients (68 percent) had positive cultures including herpes (50 percent), cytomegalovirus (25 percent),Neisseria gonorrhoeae (16 percent), chlamydia (16 percent), acidfast bacilli (2 percent), and others (9 percent). Six of 32 patients with positive cultures had more than one organism cultured. Sixteen (50 percent) patients with positive cultures were treated medically, 8 (25 percent) were treated surgically and 8 (25 percent) were treated with both modalities. Sixty-one procedures were performed on 17 patients for condylomata. Eighteen patients had 20 procedures for abscesses, 50 percent of whom had positive cultures for other than common bowel flora; all improved. Fourteen patients underwent 33 procedures for perianal fistulas.Mycobacterium fortuitum was cultured from one patient who required 13 procedures for abscesses and fistulas. Forty-five (96 percent) patients were followed for an average of 12.5 months ±2.9 SEM (range, 1–94 months). Symptoms were improved or resolved in 22 of 32 (69 percent) patients with positive cultures and in 11 of 13 (84 percent) with negative cultures. CONCLUSIONS: Specific pathogens may often be identified in human immunodeficiency virus-seropositive patients with anorectal disorders if aggressively sought. Although patients without specific pathogens identified may be expected to improve with planned empiric treatment, positive identification allows more directed therapy.