快速心房起搏对家兔L-型钙通道和Kv4.3钾通道基因表达的影响

目的观察快速心房起搏对家兔心房L型钙通道亚单位和Kv4.3钾通道基因表达的影响。方法新西兰大耳白家兔36只,随机分成6组,经右颈外静脉穿刺置入电极于右房,分别给予0、3、6、12、24或48h快速心房起搏,停止起搏后取右房组织,应用半定量反转录聚合酶链式反应测定各时相点L型钙通道α1c,β1,α2亚单位,钾通道Kv4.3mRNA的表达水平。结果L型钙通道α1c、β1亚单位在快速起搏6h后表达水平下调,并随着起搏时间的延长进一步下调。α2亚单位的mRNA表达在各时相点无显著差异。Kv4.3的mRNA的表达在快速起搏的24h和48h下降分别达55.50%（P<0.01）和59.12%（P<0.01）。48h后下降达到一个平台期。结论快速心房起搏可导致L型钙通道亚单位和Kv4.3钾通道mRNA表达下调。     

兔慢性心力衰竭心房肌细胞离子通道重构及分子机制

目的 观察兔慢性心力衰竭(CHF)心房肌细胞复极离子通道电流的变化及孔道蛋白mRNA的改变,探讨心力衰竭房性心律失常的可能机制.方法 使用结扎左室支建市兔心衰模型;用全细胞膜片钳记录兔心房肌细胞L钙通道电流(ICa-L)、瞬时外向钾电流(Ito)的变化;用定量PCR方法测定兔心房肌细胞L型钙通道α1、Kv4.3、钠钙交换蛋白的mRNA表达.结果 心衰组和假手术组兔心房肌细胞ICa-L峰电流密度分别为(-4.79±0.80)pA/pF和(-7.19±1.82)pA/pF(P<0.01),其α1 mRNA表达分别为1.10±0.27(×10-1)和1.73+0.33(×10'-1>)(P<0.01).心衰组与假手术组心房肌细胞的Lto峰电流密度分别为(15.60±1.60)pA/pF和(28.70±2.71)pA/pF(P<0.01),其Kv4.3 mRNA分别为3.13±0.36(×10)和6.30±0.61(×10)(P<0.01);心衰组与假手术组心房肌细胞钠钙交换蛋白mRNA的含最分别为2.76±0.60(×10)和1.02±0.14(×10)(P<0.01).结论 兔慢性心力衰竭心房肌细胞ICa-L、Ito电流密度下调,孔道亚单位α1、Kv4.3 mRNA表达减少可能是其机制之一,同时钠钙交换蛋白mRNA的含量增加,可能是导致房性心律失常的原因.     

肺静脉源性房颤模型中L型钙通道α1、α2亚基mRNA表达的研究

目的:研究肺静脉源性房颤动物模型中L型钙通道α1、α2亚基mRNA的表达,以阐明肺静脉源性房颤发生的分子机制。方法:通过建立兔肺静脉源性房颤的动物模型,按房颤持续时间的不同分组,应用半定量逆转录聚合酶链反应测定各实验组的兔肺静脉和心房组织L型钙通道α1、α2亚基mRNA表达水平。结果:随着房颤持续时间的延长（0.5～6h）,兔肺静脉和心房组织L型钙通道α1亚基mRNA表达水平逐渐下调,至房颤发生后2h时,较对照组差异有显著性（P<0.05）;而同样实验条件下,兔肺静脉和心房组织L型钙通道α2亚基mRNA表达水平未出现明显变化,与对照组比较无显著性差异（P>0.05）。结论:兔肺静脉和心房组织L型钙通道α1亚单位基因转录下调可能是肺静脉源性房颤所致肺静脉和心房电重构的中心机制之一,而在引起L型钙通道功能性下调的因素中,其辅助性亚单位α2所起的调节作用较小。     

钾流在糖尿病大鼠心室肌细胞的改变机制

目的 研究糖尿病对大鼠心室肌细胞瞬间外向钾流(Ito)的影响及其分子机制,探讨糖尿病引起的心脏损害与心律失常的关系.方法 取体质量150～200 g的雄性Sprague-Dawley大鼠,单次腹腔注射链脲菌素(STZ,65 mg/kg,pH=4.5)建立糖尿病大鼠模型,采用酶解法获得单个心室肌细胞,应用膜片钳全细胞方法记录Ito;并用反转录聚合酶链式反应技术进一步半定量编码该电流通道α亚单位基因(Kv4.2、Kv4.3和Kv1.4)mR-NA的表达水平.结果 与对照组比较, 70 mV时,糖尿病大鼠心室肌细胞Ito密度显著降低[对照组:(30.6±3.8)比糖尿病组:(18.9±3.3)pA/pF,P<0.01);半定量分析法显示糖尿病大鼠心室肌细胞Ito通道α亚单位编码基因Kv4.2、Kv4.3 mRNA表达水平分别下调56.9%和46.6%;而Kv1.4 mRNA表达则上调约48.0%,3组基因表达水平的改变差异均有统计学意义(P<0.05).结论 糖尿病大鼠心室肌细胞Ito密度显著降低主要与编码该通道α亚单位的基因表达下调有关.     

房颤心房肌L型钙通道α1c亚单位mRNA的表达及意义

目的研究房颤心房肌L型钙通道结构重塑的分子基础。方法心脏手术中采集慢性房颤及窦性心律患者的右心房肌,提取总RNA行逆转录,用PCR技术检测L型钙通道α1c亚单位不同位置的mRNA片段表达。结果①α1c亚单位Ⅰ~Ⅱ跨膜区连接对应的mRNA丰度在慢性房颤心房肌与窦性心律心房肌无明显差异。②α1c亚单位Ⅳ跨膜区对应的mRNA丰度则慢性房颤心房肌较窦性心律心房肌明显降低。结论房颤心房肌L型钙通道结构重塑与α1c亚单位的亚型表达改变有关。     

房颤心房肌L型钙通道仅α1c亚单位mRNA的表达及意义

目的研究房颤心房肌L型钙通道结构重塑的分子基础。方法心脏手术中采集慢性房颤及窦性心律患者的右心房肌，提取总RNA行逆转录，用PCR技术检测L型钙通道α1c亚单位不同位置的mRNA片段表达。结果①α1c亚单位Ⅰ～Ⅱ跨膜区连接对应的mRNA丰度在慢性房颤心房肌与窦性心律心房肌无明显差异。②α1c亚单位N跨膜区对应的mRNA丰度则慢性房颤心房肌较窦性心律心房肌明显降低。结论房颤心房肌L型钙通道结构重塑与α1c亚单位的亚型表达改变有关。     

快速心房起搏对家兔L型钙通道和钾通道Kv4.3mRNA与蛋白表达的影响

目的建立家兔快速心房起搏模型,探讨快速心房起搏早期心房超微结构变化和相关离子通道基因和蛋白表达的改变。方法36只家兔给予600次／min的频率进行心房起搏,按起搏时间分成6组,透射电镜观察心房肌超微结构变化,用反转录聚合酶链反应进行检测L型钙通道αlc、B1、以亚单位和钾通道Kv4．3的mRNA表达,Westernbolt检测L型钙通道αlc、钾通道Kv4．3的蛋白表达。结果心房肌细胞超微结构的改变在起搏3h后出现,随着起搏时间的延长,出现线粒体空泡化、肌丝溶解和糖原聚集。L型钙通道的αlc、β1的mRNA表达下调出现在起搏6h后;在24h后并没有随着起搏时间的延长而进一步下降,钾通道Kv4．3的mRNA表达在起搏24h后开始明显下降,以亚单位的表达水平在起搏后没有改变。L型钙通道的αlc、钾通道Kv4．3的蛋白表达水平改变与相应的mRNA表达改变相平行。结论在快速起搏早期,L型钙通道和钾通道Kv4．3的基因和蛋白表达水平下降,心房肌细胞超微结构改变早于离子通道表达水平发生变化,主要的机制可能是与快速起搏引起的钙超载导致离子通道转录水平的下降有关。     

钾流在糖尿病大鼠心室肌细胞的改变机制

目的研究糖尿病对大鼠心室肌细胞瞬间外向钾流(I_(to))的影响及其分子机制,探讨糖尿病引起的心脏损害与心律失常的关系。方法取体质量150～200 g 的雄性 Sprague-Dawley 大鼠,单次腹腔注射链脲菌素(STZ,65 mg/kg,pH=4.5)建立糖尿病大鼠模型,采用酶解法获得单个心室肌细胞,应用膜片钳全细胞方法记录I_(to);并用反转录聚合酶链式反应技术进一步半定量编码该电流通道α亚单位基因(Kv4.2、Kv4.3和 Kv1.4)mR-NA 的表达水平。结果与对照组比较,+70 mV 时,糖尿病大鼠心室肌细胞 I_(to)密度显著降低[对照组:(30.6±3.8)比糖尿病组:(18.9±3.3)pA/pF,P<0.01);半定量分析法显示糖尿病大鼠心室肌细胞 I_(to)通道α亚单位编码基因 Kv4.2、Kv4.3 mRNA 表达水平分别下调56.9%和46.6%;而 Kv1.4 mRNA 表达则上调约48.0%,3组基因表达水平的改变差异均有统计学意义(P<0.05)。结论糖尿病大鼠心室肌细胞 I_(to)密度显著降低主要与编码该通道α亚单位的基因表达下调有关。     

辛伐他汀对大鼠心肌肥厚的防治作用及其与钙通道的关系

目的 探讨辛伐他汀对心肌肥厚的防治作用及其与钙通道活动的关系.方法 采用腹主动脉缩窄术建立心肌肥厚动物模型.尾动脉无创测量大鼠收缩压.称量心脏重量/体重(HW/BW)、左心室重量/体重(LVW/BW)比值.采用超声心动图检测动物心脏构型及射血功能.应用RT-PCR和Western blot分别检测心肌L-型钙通道亚单位Cav1.2(α,C)、T-型钙通道亚单位Cav3.1 (α1G)、Cav3.2(α1H)mRNA及其蛋白表达的变化.结果 (1)腹主动脉缩窄+辛伐他汀组(AAC+SIM组)大鼠收缩压130 mm Hg(1 mm Hg=0.133 kPa)明显低于腹主动脉缩窄组(AAC组)189mm Hg,P<0.05.HW/BW比值AAC+SIM组3.37 mg/g明显低于AAC组3.94 mg/g,P<0.01.LVW/BW比值AAC+SIM组2.33 mg/g明显低于AAC组2.95 mg/g,P<0.01.室间隔厚度AAC+SIM组2.01 mm明显低于AAC组2.31 mm,P<0.01.左心室后壁厚度AAC+SIM组1.89 mm明显低于AAC组2.19 mm,P<0.01.(2)AAC+SIM组大鼠心肌T-型钙通道亚单位α1G、α1H mRNA和蛋白表达均显著低于AAC组,P均<0.01,但L-型钙通道亚单位α1 C mRNA和蛋白表达两组间比较差异无统计学意义.结论 辛伐他汀对腹主动脉缩窄所致的心肌肥厚具有明显的防治作用,其作用机制可能与其抑制T-型钙通道亚单位α1G、α1H mRNA和蛋白的重新再表达有关,但与L-型钙通道亚单位α1C mRNA和蛋白表达无关.     

慢性心房颤动患者心房肌KChIP2基因mRNA水平的定量检测

目的 心房颤动(房颤)是最为常见的快速性心律失常之一.钾通道相关蛋白2(K+channel interacting protein 2,KChIP2)是心肌细胞瞬时外向钾通道的重要辅助亚单位,在,Ito发挥正常功能中起着重要的作用.报告采用实时荧光定量聚合酶链反应(PCR)技术通过对房颤时KChIP2和Kv4.3基因mRNA水平进行定量研究,探讨KChIP2在房颤中的作用和对于瞬时外向钾通道的可能调控机制.方法 (1)30例风湿性心脏病患者分为两组:窦性心律组(窦律组)13例,持续性房颤组(房颤组)17例,取其常规切除的右心耳组织作为研究对象;(2)提取心房肌组织总RNA,通过RT-PCR和TA克隆技术构建含有目的 基因片段的质粒标准品;(3)以GAPDH为内参照基因,采用SYBR Green I法实时荧光定量PCR技术检测持续性房颤和窦律患者KChIP2和Kv4.3基因mRNA水平.结果 (1)标准曲线和熔解曲线:标准曲线线性关系良好,相关系数R2＞0.99.熔解曲线呈明显单峰状,退火温度与预测值基本一致;(2)窦律组和房颤组KChIP2/GAPDH比值分别为0.2200±0.0388、0.1468±0.0452,房颤组KChIP2基因mRNA水平低于窦律组,P＜0.01;窦律组和房颤组Kv4.3/GAPDH比值分别为0.5257±0.1427、0.3946±0.1826,房颤组Kv4.3基因mRNA水平低于窦律组,P＜0.05.结论 与窦律患者相比,房颤患者KChIP2基因和Kv4.3基因明显下调,KChIP2和Kv4.3基因下调是房颤时Ito电流下调的分子基础.     

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.