Estradiol-induced accumulation of vitellogenin mRNA and secretion of vitellogenin in liver cultures of Xenopus

Expiants of male Xenopus liver maintained in a serum-free culture medium respond to stimulation by 2 × 10^?8 M 17β-estradiol with an increasing rate of accumulation of vitellogenin mRNA, as revealed by hybridization of cDNA to the total cytoplasmic RNA extracted from the cultures. A similar response is observed for secretion of ³²PO₄-labeled vitellogenin into the culture medium. The in vitro response is improved in liver tissue of prestimulated animals, and by adaptation of liver expiants to the culture medium prior to hormone treatment, but attains only about 10% of the in vivo response. Since essential features of the in vivo response are maintained in liver expiants, organ culture appears suitable for investigating initial events of estradiol action leading to enhanced synthesis of vitellogenin.     

A comparison of sotalol and procainamide in symptomatic ventricular tachycardia

Summary The effects of oral sotalol were compared with 1000 and 1500 mg of procainamide in 23 patients with sustained ventricular tachycardia. The predictive value of an induction study after procainamide was assessed. The mean age of the study group was 62±12 years, and the mean ejection fraction was 32±16%. The cycle length (CL) of the induced tachycardia, the coupling interval (CI) of the first extrastimulus (in ms), and the number of noninducible (NI) patients are given in the table below. One patient developed torsades during the loading period of sotalol and is included in the number requiring cardioversion (DC). Important proarrhythmic effects (spontaneous occurrence of tachycardia) were seen twice after procainamide. Induction suppression by procainamide predicted success with sotalol (p=0.0013).Conclusion: Ventricular tachycardia seems to be less often inducible after oral sotalol than after procainamide. The success of procainamide during programmed electrical stimulation predicts the same for sotalol. If ventricular tachycardia remains inducible after oral sotalol, it is faster than after procainamide but slower than the baseline tachycardia. Both drugs slightly prolong refractoriness.     

Molecular mimicry of mitochondrial and nuclear autoantigens in primary biliary cirrhosis

BACKGROUND & AIMS: The mechanism for development of primary biliary cirrhosis (PBC) remains enigmatic, but molecular mimicry has been implicated because of well-known cross-reactivity of human mitochondrial autoantigens and equivalent bacterial antigens. Virtually all patients with PBC have antimitochondrial autoantibodies (AMA), but, interestingly, approximately 50% also manifest antinuclear antibodies (ANA). METHODS: To determine whether generation of ANA are due to molecular mimicry of mitochondrial peptides, we established 6 T-cell clones selected by a peptide corresponding to the E2 subunit of mitochondrial pyruvate dehydrogenase complex and analyzed for reactivity to mimicry peptides derived from mitochondrial and nuclear autoantigens, including control sequences. RESULTS: For mitochondrial autoantigens, 1 peptide from the E2 subunit of the pyruvate dehydrogenase complex, 1 peptide from the E2 subunit of the oxo-glutarate dehydrogenase complex, 1 peptide from the E2 subunit of the branched-chain 2-oxoacid dehydrogenase complex, and 1 peptide from the E3-binding protein cross-reacted with these T-cell clones. For the nuclear autoantigens, 5 peptides from gp210 and 1 from Sp100 cross-reacted with these clones. Furthermore, 1 of 3 T-cell clones selected by recombinant gp210 protein reacted with a mimicry peptide corresponding to amino acids 188-201 of gp210, indicating that this part of the protein is a naturally processed immunodominant T-cell epitope. CONCLUSIONS: These results demonstrate molecular mimicry between mitochondrial and nuclear autoantigens in PBC and that a mimicry peptide may become an immunodominant T-cell epitope. These data have significance not only for PBC but also for the production of ANA in other disease processes.     

A Prospective,Randomized Study: Switch Off the Sacral Nerve Stimulator During the Night?

Purpose Sacral nerve stimulation is an effective treatment for fecal incontinence. Some have recommended to “switch off” the pacemaker during the night to extend the lifetime of the expensive pacemaker. This study was designed to investigate whether a nightly “switch off” affects the clinical results of sacral nerve stimulation. Methods Twenty patients successfully treated with sacral nerve stimulation (19 females; median age, 59 (range, 36–72) years) were randomized to: Group A, pacemaker continuously “on” for three weeks followed by three weeks with the pacemaker “off” during the night, or Group B, opposite order. Daily bowel-habit diary, Wexner, and St. Mark’s incontinence scores were obtained. Results One failed to return the daily bowel-habit diary, leaving 19 participating patients. Median Wexner incontinence score increased from 6 (range, 2–14) to 7 (range, 3–16) during the “off” period (P = 0.04), whereas St. Mark’s incontinence score increased from 10 (range, 3–16) to 11 (range, 3–18; P = 0.03). Median number of days with soiling per three weeks increased from 0 (range, 0–12) to 1 (range, 0–15) during the “off” period (P = 0.008). Seven of 19 had more days with soiling during the “off” period. Defecation frequency per three weeks increased from 26 (range, 11–71) to 34 (range, 9–70) during the “off” period (P = 0.19). Only four continued with a nightly “switch off” after the study. Conclusions It could be considered to recommend compliant patients to “switch off” the pacemaker during the night to extend the lifetime of the pacemaker. One-third experienced increased soiling, and they should turn the pacemaker on all day and night. Among the remaining, only a minor proportion will be motivated for turning the pacemaker off. Read at the meeting of the European Society of Coloproctology, Malta, September 26 to 29, 2007.     

Safety,reliability, and operability of cochlear implant electrode arrays coated with biocompatible polymer

Conclusion: Polymer-coated electrodes can reduce surgically-induced trauma associated with the insertion of a cochlear implant (CI) electrode array. Objectives: To evaluate if insertion trauma in CI surgery can be reduced by using electrode arrays coated with 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer. Methods: We analyzed characteristics of the Contour Advance® electrode arrays coated with MPC polymer. To assess surgical trauma during electrode insertion, polymer-coated or uncoated (n = 5 each) animal electrode arrays were implanted in guinea pig cochleae and operability and electrophysiological and histological changes were assessed. Results: Under light and scanning electron microscopy, polymer-coated electrodes did not appear different from uncoated electrodes, and no change was observed after mechanical stressing of the arrays. Electrode insertion was significantly easier when polymer-coated electrodes were used. Auditory brainstem response (ABR) thresholds did not differ between groups, but p1-n1 amplitudes of the coated group were larger compared with the uncoated group at 32 kHz at 28 days after surgery. The survival of outer hair cells and spiral ganglion cells was significantly greater in the polymer-coated group.     

Encainide for the Treatment of Refractory Ventricular Tachycardia in Patients Undergoing Programmed Electrical Stimulation

Encainide was evaluated in 26 patients undergoing programmed electrical stimulation (PES) for ventricular arrhythmias. These patients had inducible symptomatic ventricular tachyarrhythmias during baseline PES and had previously failed a mean of 3.2 antiarrhythmic agents. Encainide was discontinued in six patients prior to PES because of spontaneous ventricular tachycardia (VT) (five patients) and adverse effect (one patient). Encainide increased, the PR, QRS, QTc intervals, and right ventricular effective refractory period (RVERP) significantly from baseline (P < 0.05) in 16 patients who were extensive metabolizers. Encainide, at a mean dose of 110 ± 28 mg/day increased the ventricular tachycardia cycle length (VTCL) from 278 ± 77.1 msec to 334 ± 68.8 msec (P < 0.05). Encainide alone was effective (< 15 beats induced) or partially effective (converting inducible sustained VT to < 15 beats asymptomatic nonsustained VT or increasing the VTCL < 100 msec with no symptoms) in two and seven patients respectively. In seven patients, encainide was also reevaluated at a higher dose (mean dose 148 ± 22 mg/day), but this dose did not significantly alter the overall response or measured parameters. Seven patients were subsequently evaluated on combination of encainide and another antiarrhythmic agent. The combination was effective in three patients and partially effective in three patients. Serum concentrations were measured during each testing period; a moderate correlation was observed between the PR and RR intervals and total concentrations in patients who were extensive metabolizers. Eleven patients who were effective or partially effective during acute testing were placed on long-term encainide therapy (three patients alone and eight patients on combination therapy). In a mean follow-up of 8.9 months (1–25 months) encainide was discontinued in five patients (two patients due to nonsudden cardiac death, one patient due to recurrent nonfatal VT, and two patients due to side effects of combination therapy.) Conclusion: Encainide alone is minimally effective (7.7%) for preventing inducible ventricular tachycardia, but partially effective in 38.9%. Retesting at a higher dose does not offer any additional benefit. However, encainide in combination with another antiarrhythmic agent may improve the response in patients who remain inducible on encainide alone. Further studies are needed to verify this observation.     

Beta-adrenergic stimulation of pig myocytes with decreased cytosolic free magnesium prolongs the action potential and enhances triggered activity

INTRODUCTION: Heart failure results in chronic beta-adrenergic stimulation, repolarization lability, and arrhythmias associated with early afterdepolarizations (EADs) and delayed afterdepolarizations (DADs). Having described a significant reduction in intracellular free magnesium ([Mg2+]i) in experimental heart failure, we asked whether a reduction in [Mg2+]i would delay repolarization or facilitate EADs and/or DADs. METHODS AND RESULTS: Left ventricular myocytes were isolated from Yorkshire swine. Cytosolic free [Mg2+] was set at 0.12 mM (LoMg) or 1.2 mM (HiMg) through pipette dialysis. Action potentials (AP), Ca current (I(Ca)), and sodium/calcium exchange current (I(NCX)) were measured in the presence or absence of isoproterenol (2 microM) at 37 degrees C. Under basal conditions (0.1-Hz stimulation, 2 mM external [Ca2+]), reducing [Mg2+]i had no effect on AP duration and I(Ca) but did significantly enhance I(NCX). In contrast, during superfusion with isoproterenol, reduced [Mg2+]i caused a significant increase in AP duration at both 50% and 90% repolarization (APD50 and APD90) compared with HiMg (P < 0.05). LoMg cells manifested a high incidence of triggered activities, including spontaneous AP, EADs, and DADs (83.3% in LoMg, n = 12 vs 38.3% in HiMg, n = 13; P < 0.05). I(Ca) and I(NCX) were significantly increased in LoMg cells compared with HiMg cells (P < 0.05). CONCLUSION: Decreased cytosolic free magnesium prolongs AP duration and increases the incidence of triggered activity during beta-adrenergic stimulation. These effects may be due to increased I(Ca) and I(NCX) in the presence of reduced intracellular [Mg2+]. A magnesium-dependent increase in triggered activity coupled with delayed repolarization during beta-adrenergic stimulation could contribute to the arrhythmogenic substrate in heart failure.     

3种方法测量牙齿根管工作长度准确性的比较研究

目的：探讨指感法、X光数字化成像法、电测法测量根管工作长度的准确性。方法：选取拟行根管治疗的恒前牙病例共600颗患牙,按照随机数字表法将其分为感法组207颗、X光数字化成像法组202颗和电测法组191颗,分别使用指感法、X光数字化成像法、电测法进行根管工作长度测量,并以此长度根管预备后试尖判断准确性。结果：电测法的准确率90.58%明显高于指感法的58.46%和X光数字化成像法的71.78%,差异均有统计学意义（P〈0.01）,而X光数字化成像法的准确率明显高于指感法,差异有统计学意义（P〈0.05）。结论：Raypex5测量仪是一种操作方便、准确率高的根管工作长度测量仪,X光数字化成像系统作为辅助应用于根管治疗中。     

精神分裂症顽固性幻听实施双背侧前额叶低频重复经颅磁刺激治疗的效果研究

目的：分析双背侧前额叶低频重复经颅磁刺激治疗精神分裂症顽固性幻听的临床效果。方法：选取本院2012年3月-2013年3月收治的28例精神分裂症顽固性幻听患者,按照随机数字表法将其分成对照组和观察组各14例,对照组采用1 Hz伪刺激治疗,观察组采用1 Hz真刺激治疗,分析比较两组患者的治疗效果。结果：观察组的幻听症状、精神病理症状以及总评分改善情况均明显优于对照组,差异均有统计学意义（P〈0.05）。幻听症状改善主要表现在：观察组患者的幻听声音大小以及频率改善情况明显优于对照组,且患者的抑郁、焦虑等精神病理症状和意志活动方面的阴性症状均较对照组有所改善,比较差异均有统计学意义（P〈0.05）。结论：1 Hz的双背侧前额叶低频重复经颅磁刺激（rTMS）治疗精神分裂症顽固性幻听效果显著,且安全系数高,值得深入研究。     

生物反馈在压力性尿失禁非手术治疗中的价值

目的 通过Meta分析了解生物反馈在压力性尿失禁非手术治疗中的价值,旨在获得压力性尿失禁物理治疗的最佳方法. 方法 使用“biofeedback”及“stress urinary incontinence”及相应中文名关键词检索Pubmed、维普中文科技期刊全文数据库、万方数字化期刊全文、中国知网全文数据库所有文献,选取以生物反馈为对照治疗压力性尿失禁的文献,应用Review Manager 5.2软件进行统计学分析. 结果 共计18篇文献纳入研究.在压力性尿失禁非手术治疗中,生物反馈＋盆底肌锻炼与盆底肌锻炼对照治疗的有效率明显提高;生物反馈＋神经电刺激与盆底肌锻炼对照治疗的有效率明显提高;生物反馈＋盆底肌锻炼＋神经电刺激与盆底肌锻炼对照治疗的有效率明显提高,差异均有统计学意义. 结论 生物反馈在压力性尿失禁非手术治疗中有较好治疗效果,值得临床推广.