心室肌复极快慢与尖端扭转型室性心动过速发生率的性别差异

目的 :观察雌雄兔离体心室肌复极时程的差异 ,探讨其与尖端扭转型室性心动过速 (TdP)性别差异的关系。方法 :以Langendorff法依次用台氏液、含索他洛尔的台氏液和含索他洛尔的低钾、镁台氏液灌流离体兔(雌雄各 8只 )心 ,记录雌、雄兔心用索他洛尔前后心内膜单相动作电位 ,比较雌雄兔在低钾、镁台氏液灌流后TdP发生率的差异。结果 :用索他洛尔前 ,起搏周期 (CL)从 4 0 0ms延长至 180 0ms,雄兔内膜单相动作电位时程复极90 %的时限 (MAPD90 )由 (181.0± 6 .5 )ms延长到 (2 14 .0± 7.5 )ms ,增幅 (18.2± 8.3) % ;雌兔内膜MAPD90 由(186 .0± 6 .3)ms延长至 (2 76 .0± 8.2 )ms。增幅 (48.4± 9.4 ) %。用索他洛尔后 ,CL从 4 0 0ms增至 180 0ms,雄兔内膜MAPD90 由 (2 2 4 .0± 6 .9)ms延长到 (2 95 .0± 7.6 )ms ,增幅 (31.7± 8.7) % ;雌兔内膜MAPD90 由 (2 34.0±6 .3)ms延长至 (376 .0± 9.7)ms,增幅 (6 0 .7± 8.5 ) %。用索他洛尔前后雌兔内膜MAPD90 均明显长于雄兔 (P<0 .0 1)。 7只雌兔发生TdP ,发生率 87.5 % ;1只雄兔发生TdP ,发生率 12 .5 %。结论 :复极快慢的不同可能是TdP发生率性别差异的主要原因     

钙调蛋白拮抗剂W-7抑制索他洛尔诱发离体兔心尖端扭转型室性心动过速

目的观察钙调蛋白拮抗剂W-7对离体兔心实验性尖端扭转型室性心动过速(TdP)的影响,并探讨其机制。方法采用Langendorff灌流技术,在三度房室传导阻滞和低钾(1．5mmol／L)、低镁(0．35mmol／L)的条件下,用索他洛尔(30μmol／L)灌流离体雌兔心脏,建立TdP模型。36只雌兔心脏随机分为索他洛尔组和W-7低浓度(20μmol／L)、中浓度(50μmol／L)、高浓度(100μmol／L)干预组,每组各9只兔。灌流全程同步记录不同起搏周长下的心电图和左室内、中、外三层心肌的单相动作电位复极时程,并观察各组QT间期、跨室壁心肌复极离散度(TDR)、早期后除极(EAD)和TdP的诱发率。结果索他洛尔逆频率依赖性延长兔QT间期和增大左室三层心肌TDR,并有较高的。EAD(100％)和TdP(78％)诱发率。W-7浓度依赖性地抑制EAD诱发率(20μmol／L为56％,50μmol／L为44％,100μmol／L为11％)和TdP诱发率(20μmol／L为44％,50μmol／L为22％,100μmol／L为11％),但对QT间期和TDR均无影响。结论抑制钙调蛋白活性能够抑制离体兔心实验性TdP的发生,这种作用主要通过抑制EAD的机制而非通过影响跨室壁复极异质性的机制来发挥。     

迷走神经刺激对心力衰竭兔跨室壁复极离散的影响

目的探讨迷走神经刺激对心力衰竭(简称心衰)兔跨室壁复极离散度(TDR)的影响。方法用阿霉素制作兔心衰模型,采用单相动作电位(MAP)记录技术分别记录10只开胸心衰兔(心衰组)和10只开胸正常兔(对照组)迷走神经刺激前后左室游离壁心尖上方1cm处三层心肌的MAP,测量并分析MAP时程(MAPD),TDR。结果对照组刺激前后TDR没有显著性差异,心衰组刺激后TDR显著减少(P<0.05)。迷走神经刺激前,与对照组比较,心衰组TDR明显延长(12.80±2.57ms vs8.82±1.33ms,P<0.05),刺激后两者相比无显著性差异(7.89±3.80ms vs9.44±3.21ms,P>0.05)。结论迷走神经刺激可使心衰组的TDR降低。     

硫酸镁对家兔在体心脏跨室壁心肌复极不均一性的影响

目的：观察静脉注射索他洛尔后，硫酸镁对家兔跨室壁心肌复极不均一性的影响，探讨其治疗室性心律失常的机制。方法：采用单相动作电位（monophasic action potential,MAP)记录技术，同步记录12只开胸兔左室心外膜心肌、中层心肌和心内膜心肌的MAP，在静脉注射索他洛尔基础上，静脉滴注硫酸镁后观察其对心肌得极不均一性的影响。结果：（1）索他洛尔剂量依赖性地显延长中层心肌的MAP复极100％时程，增加跨室壁复极离散度（transmural dispersion of repolarization,TDR)；静脉滴注硫酸镁后TDR明显减少。（2）索他洛尔剂量依赖性地诱发早期后除极（early afterdepolarization,EAD)和尖端扭转型室性心动过速（torsade de pointes,TdP)的发生率；硫酸镁抑制索他洛尔诱导的EAD和TdP。结论：硫酸镁逆转索他洛尔所致的TDR增加，抑制索他洛尔诱导产生EAD，其治疗TdP的机制可能与此有关。     

索他洛尔对兔在体心脏左心室壁心肌复极不均一性影响的实验研究

目的　观察索他洛尔对兔在体心脏左心室壁各层心肌复极的影响 ,以证实在体心肌 M细胞的存在 ,探讨其与心律失常的关系。　方法　采用单相动作电位 (m onophasic action potential,MAP)记录技术 ,同步记录 12只开胸兔左心室外膜心肌 (epicardium ,Epi)、中层心肌 (m id- myocardium ,Mid)和心内膜心肌 (endocardium ,Endo)的 MAP,静脉注射索他洛尔后 ,测量 3层心肌 MAP的复极时限和跨心室壁心肌复极离散度 (transm ural dispersion of repolarization,TDR)。　结果　 1用药前 Epi、Mid、Endo的 MAP10 0 %复极时限 (APD1 0 0 )分别为 (136± 16 )、(15 2± 19)、(15 0± 2 0 ) m s,TDR为 (17± 8) m s。每间隔 30 m in静脉注射索他洛尔 0 .5、1.0、1.5和 2 .0 m g· kg- 1后发现 ,索他洛尔剂量依赖性延长 3层心肌的 APD1 0 0 ,其中以延长 Mid的 APD1 0 0 更为明显 ,对 Epi和 Endo的 APD1 0 0 延长程度相近 ,使 TDR增加 ;至静脉注射 2 .0 mg· kg- 1 后 ,Epi、Mid、Endo的 APD1 0 0 分别为 (177± 30 )、(2 34± 32 )、(194± 30 ) ms,TDR为 (5 7± 15 ) ms(P <0 .0 5 ) ;2索他洛尔剂量依赖性地增加尖端扭转性室性心动过速 (torsade depointes,TDP)的发生率。　结论　在体兔心肌存在 M细胞。索他洛尔增加兔     

在体心脏早期后除极起源的电生理学研究

探讨在体心脏早期后除极 (EAD)的起源及其与室性心律失常的关系。采用单相动作电位 (MAP)记录技术 ,同步记录 12只开胸兔左室心外膜下心肌 (Epi)、中层心肌 (Mid)、心内膜下心肌 (Endo)的MAP ,并静脉注射 (简称静注 )索他洛尔诱发EAD后 ,观察三层心肌EAD的发生。结果 :①索他洛尔呈剂量依赖性地增加EAD和尖端扭转型室性心动过速 (TdP)的发生率。静注索他洛尔 0 .5mg kg和 1.0mg kg后无EAD和Tdp ;剂量增至 2 .0mg kg后 ,7只兔的MAP上出现了EAD ,其中 4只兔诱发了TdP。②静注索他洛尔后 ,在Mid比Epi和Endo更容易记录EAD并具有剂量依赖性。三层心肌中以Mid的EAD振幅最高 ,当索他洛尔的剂量为 2 .0mg kg时 ,Epi、Mid和Endo的EAD振幅分别为 2 .5± 1.35 ,6 .0 8± 1.96和 3 .8± 1.46mV。此外 ,Mid的EAD出现的时相早于Epi和Endo,其中Epi和Endo的EAD的耦联间期分别与Mid的EAD的耦联间期具有相关性。③Endo的EAD的出现率多于Epi。静注索他洛尔2 .0mg kg后 ,有 3只兔的Endo的MAP上记录到了EAD ,而Epi的MAP上出现EAD的兔只有 2只。结论 :在体心脏EAD起源于中层心室肌和蒲肯野氏纤维。Ⅲ类抗心律失常药物索他洛尔致心律失常的发生机制与其诱导三层心肌EAD的程度不同有关     

兔在体左心室肥厚心肌跨室壁复极不均一性的实验研究

目的　探讨兔在体左心室肥厚心肌跨室壁复极不均一性的变化。方法　以腹主动脉缩窄术制备家兔高血压左心室肥厚模型 (腹主动脉缩窄组 ) ,并设假手术组 (仅游离腹主动脉未缩窄 )作为对照。采用自制复合式电极在兔左心室游离壁同步记录在体心内膜、心肌中层、心外膜心肌单相动作电位 (MAP) ,比较两组间跨室壁复极不均一性的差异。结果　腹主动脉缩窄组平均动脉压、左心室游离壁厚度、全心重量及其与体重比率均大于假手术组。缩窄组三层心肌单相动作电位复极至 10 0 %的时程 (MAPD1 0 0 ) (内膜 191± 19ms,中层 2 44± 2 4m s,外膜 196± 15 ms)均比假手术组 (内膜 170± 18ms,中层 172± 15 ms,外膜 168± 16m s)延长 ,以中层心肌 MAPD1 0 0 的延长最为明显 ;缩窄组跨室壁复极离散度 (TDR) (65± 10 ms)较对照组 (4± 3 m s)明显增大 (P<0 .0 1)。结论　兔在体左心室肥厚心肌跨室壁复极不均一性明显增大 ,可能是肥厚心肌心律失常发生增多的原因之一     

自主神经系统对在体犬跨室壁复极不均一性影响的研究

目的　探讨自主神经系统对在体犬跨室壁复极离散度的影响。方法　用单相动作电位(MAP)记录技术 ,同步记录 12只开胸犬左心室游离壁心外膜心肌 (epicardium ,Epi)、中层心肌(midmyocardium ,Mid)和心内膜心肌 (endocardium ,Endo)的MAP。对自主神经刺激前和刺激过程中 ,三层心肌的跨室壁复极离散度和早期后除极的发生率进行比较。结果　起搏周长为 10 0 0ms时 ,在未刺激自主神经的情况下 ,Epi、Mid和Endo的单相动作电位时程 (MAPD)复极 90 %的时限 (MAPD90 )分别是 (2 78± 11)ms、(316± 16 )ms和 (2 70± 12 )ms;其中Mid的MAPD90 明显长于Epi和Endo的MAPD90 (P<0 0 1)。刺激交感神经时 ,Epi、Mid和Endo细胞的MAPD90 分别缩短 (19± 4 )ms、(45± 6 )ms、(18± 3)ms。与刺激前相比 ,跨室壁复极离散度由 (44± 4 )ms减少到 (15± 3)ms(P <0 0 1) ;但是交感神经刺激时 ,有 5只犬 (41% )的中层心肌出现了早期后除极。迷走神经刺激对三层心肌的MAPD90 值无明显影响。结论　 (1)在体犬心室肌存在跨室壁复极不均一性 ;(2 )交感神经刺激可减少跨室壁复极离散度 ,但易在Mid诱发早期后除极 ;(3)迷走神经刺激对跨室壁复极离散度无明显影响。     

缬沙坦对兔在体肥厚心肌跨室壁复极不均一性的影响

目的:探讨兔在体左心室肥厚心肌跨室壁复极不均一性的变化及缬沙坦的影响。方法:30只兔均分为3组,分别为肥厚组(以腹主动脉缩窄术制备心肌肥厚模型);治疗组(腹主动脉缩窄术后给予缬沙坦口服);对照组(仅分离腹主动脉而不予缩窄)。采用自制复合式电极在兔左心室前壁同步记录心内膜、心肌中层、心外膜在体三层心肌单相动作电位(MAP)。结果:肥厚组平均动脉压、心脏重量及其与体重比率、左心室游离壁厚度均显著大于治疗组和对照组。肥厚组3层心肌单相动作电位时程(MAPD100)(内膜:191±19 ms,中层:244±24 ms,外膜:196±15ms)较对照组(内膜:170±18 ms,中层:172±15 ms,外膜:168±16 ms)均显著延长(中层P<0.01,内膜、外膜P<0.05,n=10),且以中层心肌MAPD100延长最为明显。而治疗组与对照组3层心肌MAPD100比较均无明显差异。结论:缬沙坦可阻止兔在体左心室肥厚心肌跨室壁复极不均一性的增大。     

跨室壁复极离散变化及其对心电图T波影响的在体实验研究

为探讨在体情况下心肌跨室壁复极离散变化及其对心电图T波影响的可能机制。运用单相动作电位 (MAP)记录技术 ,同步记录 2 1只开胸兔的左室心肌心外膜层 (Epi) ,中层 (Mid) ,内膜层 (Endo)的MAP ,分别予以减慢心率、静脉注射索他洛尔 (dl sotalol)、海葵毒素 (ATX Ⅱ )后 ,观察跨室壁复极离散的变化以及心电图T波的相应改变。结果 :①慢频率导致Mid层细胞MAP复极时间 (RT)显著延长 (从 2 0 2± 19ms到 370± 34ms,P <0 .0 5 ) ,跨壁复极离散度 (TDR)增大 (从 11± 4ms到 40± 2 1ms,P <0 .0 5 ) ,QT间期延长 (从 2 0 5± 2 1ms到 371± 30ms,P <0 .0 5 ) ,T波增宽。②dl sotalol导致Mid层细胞MAP的RT显著的延长 (从 2 0 2± 19ms到 395± 34ms,P <0 .0 5 ) ,TDR增大 (从 10± 3ms到 75± 2 5ms ,P <0 .0 5 ) ,QT间期延长 (从 2 0 8± 16ms到 397± 33ms,P <0 .0 5 ) ,三层心肌MAP的 3相复极不同程度的延长 ,使复极电位梯度变化 ,产生增宽、低幅有切迹的T波。③ATX Ⅱ导致Mid层细胞MAP的RT显著的延长 (从370± 34ms到 473± 35ms,P <0 .0 5 ) ,TDR增大 (从 40± 2 1ms到 6 2± 19ms,P <0 .0 5 ) ,QT间期延长 (从 372± 33ms到 479± 33ms,P <0 .0 5 ) ,三层心肌MAP的 2相平台期不同程度延长 ,使复极电位梯     

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.     

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.     

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.     

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.