A new periodogram using one-way analysis of variance for circadian rhythms

A new periodogram was proposed using one-way analysis of variance (ANOVA), termed ANOVA periodogram, in order to reveal a precise significant periodicity. Thirty 3-day complex computer-simulated time series with known periodicity (24 h) and three 2-h data-missing occurring periodically (23 h, 20 min) were used to compare the ANOVA periodogram with Enright's one. In results, the ANOVA periodogram was superior to Enright's periodogram in the accuracy of assessing the major periodicity.     

Effect of 3 mg melatonin on jet lag syndrome in an 8-h eastward flight

In order to assess the effect of melatonin on jet lag a field study was undertaken. The process of re-entrainment of circadian melatonin rhythm was investigated in six subjects. Except during 24-h blood sampling, the subjects were exposed to natural zeitgeber (time giver) outdoors and given 3 mg melatonin at 23:00 h. The subjects were exposed to bright sunlight from 3000 to 12000 lx. All of them showed orthodromic re-entrainment with taking melatonin, while two out of the six did not show orthodromic re-entrainment without taking melatonin. Melatonin accelerated the rate of the re-entrainment of the circadian melatonin rhythm. Melatonin was useful to jet travel from Tokyo to Los Angeles.     

Association of posterior tibial tendon abnormalities with abnormal signal intensity in the sinus tarsi on MR imaging

Objective. To evaluate the association of abnormal signal intensity within the sinus tarsi with abnormalities of the posterior tibial tendon (PTT) on MR imaging. Design and patients. Sinus tarsi abnormalities were identified on 30 ankle MR examinations in 29 patients. The PTT and anterior talofibular ligament were retrospectively analyzed for abnormalities in these same patients. Results and conclusions. Tears of the anterior talofibular ligament were found in 13 of 30 (43%) ankles. PTT abnormalities (complete tear, partial tear or dislocation) were seen in 14 of 30 (47%) studies, and were distributed relatively equally between those patients with and without lateral ligament tears. Our results provide evidence of an association between abnormalities of the PTT and the sinus tarsi. The finding of abnormal signal intensity within the sinus tarsi on MR imaging should alert the radiologist to potential abnormalities of the PTT. Received: 17 March 2000 Accepted: 17 May 2000     

The pineal gland is not essential for circadian expression of rat period homologue (rper2) mRNA in the suprachiasmatic nucleus and peripheral tissues

To investigate the functional involvement of the pineal gland in circadian expression of the rat period homolog gene (rPer2) in the suprachiasmatic nucleus (SCN) and peripheral tissues, we performed Northern blot analysis in tissues from pinealectomized rats. The ectomy did not have any significant effects on rPer2 mRNA expression patterns both in a daily light-dark condition and in a constant darkness. These results suggest that the rhythmic secretion of pineal melatonin is not essential for the circadian expression of clock genes in the SCN and other peripheral tissues of rats.     

Involvement of calmodulin-dependent protein kinase II in carbachol-induced rhythmic activity in the hippocampus of the rat

The role of calcium and protein kinases in rhythmic activity induced by muscarinic receptor activation in the CA1 area in rat hippocampal slices was investigated. Extracellular recording showed that carbachol (20 microM) induced synchronized field potential activity with a dominant frequency of 7.39+/-0.68 Hz. Pretreatment with the membrane permeable Ca(2+) chelator BAPTA-AM (50 microM) or with thapsigargin (1 microM), a compound which depletes intracellular calcium stores, reduced the dominant power of carbachol-induced theta-like activity by 83% and 78%, respectively. Inhibition of calmodulin-dependent protein kinase II (CaMKII) by the cell permeable inhibitor KN-93 (10 microM) reduced the power of carbachol-induced theta-like activity by 80%. In contrast the protein kinase C (PKC) inhibitor calphostin C did not significantly (P>0.05) affect the effect of carbachol. Whole-cell recording indicated that KN-93 also blocked carbachol-induced suppression of slow I(AHP) and strongly inhibited the carbachol-induced plateau potential. Our data suggest that activation of CaMKII by carbachol is crucial for local theta-like activity in the CA1 area of the rat hippocampus in vitro. Furthermore, involvement of CaMKII in carbachol-induced suppression of the slow I(AHP) and the induction of plateau potentials could play a role in the induction of theta-like rhythmic activity by carbachol.     

高血压患者血压昼夜节律消失与一氧化氮和内皮素关系的研究

目的探讨高血压昼夜节律与血浆一氧化氮(NO)和内皮素(ET)及其与左心室肥大的关系。方法选择原发性高血压患者90例,根据24 h动态血压(24ABPM)检测结果将其分为血压昼夜节律正常组50例及血压昼夜节律消失组40例;另选血压正常者30例作为对照组。采用G riess法测NO,用放射免疫法测ET;采用PH ILIPS HD I 5000型彩色多普勒仪测定三组受试者的室间隔厚度(IVS),左室舒张末期内径(LVDd)、左室后壁厚度(LVPW)、左心室重量(LVM),以>215 g为左心室肥大的诊断标准。结果血压昼夜节律消失组与血压昼夜节律正常组比较,ET、IVS、LVPW、LVDd、和LVM均显著增高,NO、ET、NO/ET明显降低(P<0.05)。夜间血压下降率与NO、NO/ET呈正相关(r=0.467,0.267,0.713,P<0.05),与ET、IVS、LVPW、LVDd和LVM呈负相关(r=-0.761~-0.264,P<0.05)。结论NO和ET水平可能参与昼夜血压节律的调节,ET升高与血压昼夜节律消失有关,并加重左心室肥大。     

心脏瓣膜替换术后围术期室性心律失常因素探讨及防治研究

目的探讨心脏瓣膜置换术后围术期室性心律失常的相关因素、规律、量值,以指导临床。方法观察记录156例心脏瓣膜置换术后60h内5个时间段,室性心律失常发生情况,按术式、血清钾浓度、主动脉阻断时间、心胸比、心功能等,进行分析对比研究。结果血清钾<3.5mmol/L与>4.0mmol/L组间比较差异有统计学意义(P<0.001),主动脉阻断时间>90min与<60min组间比较差异有统计学意义(P<0.01),心胸比>0.8与<0.8组间比较差异有统计学意义(P<0.05),心功能Ⅳ级与Ⅱ级组间比较差异有统计学意义(P<0.001)。结论心脏瓣膜替换术后导致室性心律失常增多的因素依次为血清钾<3.5mmol/l、主动脉阻断时间>90min、心功能Ⅳ级、心胸比>0.8。     

老年非瓣膜性心房纤颤的伴随疾病和节律控制的状况分析

目的：研究因非瓣膜性心房纤颤（房颤）住院的老年患者的伴随疾病及心律和心室率控制的状况。方法：回顾性分析12余年住院患者的240例资料，分析其房颤病程和伴随的疾病，药物治疗和起搏治疗的情况，心率和心律的变化。结果：合并心力衰竭、传导系统病变和脑卒中者分别为57．1％、31．7％和20．4％。对房颤病程不清楚者在阵发性房颤中占13．9％、在持续性房颤中占20．1％。在阵发性房颤中单独应用普罗帕酮（心律平）、B受体阻滞剂、胺碘酮治疗者分别占37．6％、25．7％和21．8％，用两种以上药物治疗者占14．9％，有7．9％的患者自行转复为窦性心律。在持续性房颤中单用地高辛、β受体阻滞剂、非二氢吡啶类钙拮抗剂治疗者分别占57．6％、23．7％和7．2％，用两种以上药物治疗者占10．8％，有20．1％的患者无需用药物控制心室率。有10．9％的阵发性房颤患者和14．4％的持续性房颤患者均行VVI起搏，主要原因分别为病态窦房结综合征和Ⅱ度以上房室传导阻滞。结论：老年非瓣膜性房颤常伴随心力衰竭、传导系统疾病和脑卒中，部分患者未及时发现和治疗房颤，大部分阵发性房颤单用普罗帕酮、β受体阻滞剂或胺碘酮可转复为窦性心律，在持续性房颤患者中，有57．6％用地高辛、20．1％不用控制心率的药物就可维持心室率。阵发性房颤和持续性房颤的起搏指征和方式均有待商榷。     

Gonadotropin-releasing hormone exhibits circadian rhythm in phase with arginine-vasopressin in co-cultures of the female rat preoptic area and suprachiasmatic nucleus

To determine whether the suprachiasmatic nucleus can drive a circadian release of gonadotropin-releasing hormone (GnRH) in the preoptic area, we measured the release of GnRH, arginine-vasopressin and vasoactive intestinal polypeptide (VIP) in cocultures of the preoptic area and the suprachiasmatic nucleus at 2-h intervals over a period of 120 h. The release of GnRH in cocultures exhibited a significant circadian rhythm in the presence of oestrogen but not in the absence of oestrogen. The period of the GnRH circadian rhythm was the same as that of the arginine-vasopressin circadian rhythm, and different from the VIP circadian rhythm in each coculture. Furthermore, the peak phase of the GnRH rhythm occurred at the time same as that of the arginine-vasopressin rhythm in each coculture. However, the peak phase of the GnRH rhythm was not always the same as that of the VIP rhythm. Administration of arginine-vasopressin significantly increased GnRH release in single preoptic area cultures in the presence of oestrogen, but VIP did not. The result suggests that, in cocultures of the suprachiasmatic nucleus and the preoptic area, arginine-vasopressin neurones drive the circadian release of GnRH in the presence of oestrogen. We suggest that arginine-vasopressin neurones in the suprachiasmatic nucleus mediate the clock information to GnRH neurones in vivo as well.     

高血压合并阻塞性睡眠呼吸暂停的动态血压特点

目的：观察高血压合并阻塞性睡眠呼吸暂停（OSA）患者的动态血压特点。方法：126例高血压研究对象均进行24h动态血乐和多导睡眠图监测，并根据睡眠呼吸暂停低通气指数分为3组：单纯高血压组（EH）、高血压合并轻度睡眠呼吸暂停组（EH＋轻度OSA组）、高血压合并中、重度睡眠呼吸暂停组（EH＋中重度OSA组），比较3组的血压、血压昼夜节律及晨峰出现的频率。结果：高血压合并OSA组与EH组相比各期血压水平均显著升高，血压昼夜节律明显下降，晨峰现象明显增加，差异均有统计学意义。且中重度组与轻度组比差异亦有统计学意义（P〈0．05或P〈0．01）。结论：高血压合并OSA患者各期血压水平、晨峰现象增加。昼夜节律明显下降，且OSA病情越重，这种变化越明显。