Circadian rhythm in atopic dermatitis—Pathophysiology and implications for chronotherapy

Circadian rhythm is a biological clock that controls a wide range of physiological functions throughout the body, including various skin functions. A 24‐h diurnal cycle, governed by an endogenous clock in the brain, largely controls cutaneous diurnal rhythm, which external factors, including temperature, humidity, diet, and stress, also modulate locally. Circadian rhythm influences cutaneous blood flow and properties of skin barrier function, such as transepidermal water loss and capacitance, and has important implications in atopic dermatitis (AD). This review explores how aberrations in circadian rhythm may play a role in the pathogenesis of AD and proposes implementation of chronotherapy to improve treatment outcomes in patients with AD.     

高龄老年高血压患者血压昼夜节律和脉压变化特征探讨

目的探讨高龄老年高血压患者血压昼夜节律和脉压变化的特点。方法将老年高血压患者346例按年龄分为2组:老年高血压组(A组)186例,年龄60~79岁;高龄老年高血压组(B组)160例,年龄80~99岁。分析2组患者动态血压参数、动态血压昼夜节律异常发生率。结果24h平均舒张压(24hDBP)高龄老年高血压组低于老年高血压组(P0.001)。老年高血压组和高龄老年高血压组24h动态脉压(24hAPP)分别为(62.06±11.79)和(66.73±11.45)mmHg。日间平均压(dABP)老年高血压组高于高龄老年高血压组(P0.01)。24hAPP老年高血压组低于高龄老年高血压组(P0.001)。老年高血压组和高龄老年高血压组血压昼夜节律异常率分别为82.80%和90.63%。结论老年高血压患者随着年龄的增大,24hDBP呈现降低趋势,24hAPP呈现增高趋势。老年高血压患者血压昼夜节律特征多数表现为非杓型和反杓型血压,且多数血压昼夜节律消失。随增龄变化老年高血压患者昼夜节律异常率增高,增龄是血压昼夜节律消失的一个重要因素。     

EFFECTS OF LOSARTAN AND BENAZEPRILON ABNORMAL CIRCADIAN BLOODPRESSURE RHYTHM AND TARGETORGAN DAMAGE IN SHRSP

The effects of chronic treatment with losartan, an angiotensin II type 1 (AT₁) receptor antagonist, and benazepril, an angiotensin converting enzyme (ACE) inhibitor, on target-organ damage and abnormal circadian blood pressure (BP) rhythm were compared in stroke-prone spontaneously hypertensive rats (SHRSP). Losartan and benazepril were given by intraperitoneal infusion for 3 weeks after 17 weeks of age to minimize any influence of their different pharmacokinetic properties. BP was continuously monitored by telemetrical method before treatment and at the end of the observation period. The left ventricular (LV) weight, 24-hour urinary albumin excretion (UalbV) and morphological changes in the kidney were observed. Losartan and benazepril (1, 3 and 10?mg/day) reduced BP and LV weight in a dose-dependent manner with good correlation between the effects. Losartan significantly improved UalbV in a dose-dependent manner, whereas benazepril was effective at only 10?mg/day. Renal morphological analysis showed that reduction of glomerulosclerosis and collagen fiber thickness was related to the effect on UalbV, but not to the antihypertensive effects. Losartan improved the shifted circadian BP rhythm towards the active phase in a dose-dependent manner, whereas the improvement caused by 1 and 3?mg/day of benazepril was less effective than the same dosage of losartan. These results suggest that both losartan and benazepril can reduce cardiac hypertrophy showing good correlation with their antihypertensive effects, but losartan, especially at a low dose, alleviates renal damage more effectively than benazepril, with its effect correlating well with improvement of the abnormal circadian BP rhythm in SHRSP. Thus, the protective effect against hypertensive target organ damage of the AT₁ receptor antagonist seems to be more effective than that of ACE inhibitor.     

Development of NMDA-induced theta rhythm in hippocampal formation slices

During the past 20 years experimental evidence has accumulated demonstrating that the appearance of theta rhythm requires a certain level of excitation of local neuronal networks. In this study we extended our earlier in vitro observations concerning the involvement of cholinergic and GABAergic neurotransmission in hippocampal theta production. Specifically, we investigated whether the hippocampal neuronal network is capable of generating theta oscillations in the presence of N-methyl-d-aspartic acid (NMDA) in a brain slice preparation. To answer this question, the effect of different concentrations of NMDA (Experiment I) and the effect of interaction between NMDA and GABA_A/_B agonists and antagonists on field potentials recorded in the CA3c region of hippocampal formation (HPC) slice preparations (Experiment II) was examined. We demonstrated for the first time that apart from the epileptiform activity recorded in almost all series of Experiments I and II, only the perfusion of HPC slices with NMDA in doses of 30 and 50 μM, as well as the perfusion of HPC slices with NMDA and GABA_B agonist baclofen (50 μM NMDA + 50 μM BACL), resulted in the appearance of individual theta epochs. The best synchronized theta oscillations obtained after administration of 50 μM NMDA + 50 μM BACL resembled theta activity induced by a bath perfusion of 50 μM carbachol. In light of the obtained results we conclude that besides the cholinergic and GABAergic input, NMDA glutamatergic drive is also important for the appearance of theta oscillations in HPC in vitro.     

心脏临时起搏支持严重心率缓慢患者的血液净化

目的观察心脏临时起搏对严重心率缓慢患者血液净化的作用。方法7例因各种病因引起的急慢性肾功能衰竭患者伴严重心率缓慢时，经右颈内静脉、左锁骨下静脉途径穿刺置管行气囊电极床边紧急心脏临时起搏，支持血液净化。结果7例中5例行右颈内静脉置管，2例行左锁骨下静脉置管，起搏均成功，效果肯定，起搏时间2～16天，支持血液净化共32次，其中连续性静脉血液滤过（CVVH）2次，8例次行血液透析滤过（HDF），22例次行常规血透（HD），未发现心脏穿孔、气胸、血胸，1例发生导管感染。1例扩张型心肌病患者因低血压心力衰竭不能控制自动出院，其余6例均抢救成功。结论球囊电极床边心脏临时起搏，操作简便快捷，安全有效，可以提高严重心动过缓合并有肾功能不全的重危患者的抢救成功率。     

Melatonin and bright-light treatment for rest-activity disruption in institutionalized patients with Alzheimer's disease

OBJECTIVES: To test whether the addition of melatonin to bright-light therapy enhances the efficacy in treating rest–activity (circadian) disruption in institutionalized patients with Alzheimer's disease (AD).
DESIGN: Randomized, controlled trial.
SETTING: Two nursing homes in San Francisco, California.
PARTICIPANTS: Fifty subjects (mean age 86) with AD.
INTERVENTION: Experimental subjects received 1 hour of morning light exposure (≥2,500 lux in gaze direction) Monday to Friday for 10 weeks and 5 mg melatonin (LM, n=16) or placebo (LP, n=17) in the evening. Control subjects (n=17) received usual indoor light (150–200 lux).
MEASUREMENTS: Nighttime sleep variables, day sleep time, day activity, day:night sleep ratio, and rest–activity parameters were determined using actigraphy.
RESULTS: Linear mixed models were employed to test the primary study hypotheses. No significant differences in nighttime sleep variables were found between groups. At the end of the intervention, the LM group showed significant improvement in daytime somnolence as indicated by a reduction in the duration of daytime sleep, an increase in daytime activity, and an improvement in day:night sleep ratio. The LM group also evidenced a significant increase in rest–activity rhythm amplitude and goodness of fit to the cosinor model.
CONCLUSION: Light treatment alone did not improve nighttime sleep, daytime wake, or rest–activity rhythm. Light treatment plus melatonin increased daytime wake time and activity levels and strengthened the rest–activity rhythm. Future studies should resolve the question of whether these improvements can be attributed to melatonin or whether the two zeitgebers interact to amplify efficacy.     

Accelerated idioventricular rhythm detected during elective surgery in a healthy man.

Accelerated idioventricular rhythm (AIVR) is found most commonly in the presence of underlying heart disease. It is characterized by acceleration of a latent pacemaker that normally depolarizes slowly. We describe a 30-year-old man who was found to have episodes of accelerated idioventricular rhythm (AIVR) on cardiac monitoring during elective orthopedic surgery. Noninvasive evaluation including two-dimensional echocardiography was unremarkable. No late potentials were detected on a signal-averaged electrocardiogram. During an exercise tolerance test, AIVR was suppressed as heart rate increased. A 24-h Holter monitor revealed that the AIVR rate was consistently 73-76 beats/min, which appeared whenever the sinus rate slowed to this level. The patient has been asymptomatic, and the rhythm has persisted at least through a 5-month follow-up period.     

昼夜节律对全身麻醉中使用丙泊酚剂量的影响

目的 观察昼夜节律对全身麻醉中使用丙泊酚剂量的影响.方法 选取2013年6月至2014年6月成都市第一人民医院行阑尾切除术患者60例(手术时间90 min内),按接受手术的时间分为B组即白天组(9:00～18:00)、D1组即夜间1组(21:00～0:00)和D2组即夜间2组(0:00～3:00),每组各20例.3组患者采用统一诱导方法,术中以目标脑电双频指数(BIS)值(40～55)闭环反馈靶控输注(TCI)丙泊酚3μg/mL,瑞芬太尼TCI4 ng/mL至术毕.分别记录3组患者T.(入室后5 min)、T1(插管即刻)、T2(插管后5 min)、T3(手术结束时)、T4(拔管时)和T5(拔管后5 min)的BIS值以及平均动脉压(MAP)、心率(HR);记录3组患者麻醉期间丙泊酚和瑞芬太尼使用的总量及停药后的麻醉苏醒时间.结果 D2组的MAP、HR均低于B组,麻醉前后的BIS值也低于B组,差异有统计学意义(P＜0.05).在同一麻醉深度下,D2组所需的丙泊酚用量低于B组,差异有统计学意义(P＜0.05).结论 昼夜节律可以对全身麻醉中的丙泊酚用量产生影响,夜间手术的全身麻醉中丙泊酚所需药量低于白天,可以适当减量.