新生大鼠反复惊厥对NMDA受体表达的长期影响

目的：研究反复惊厥对大鼠脑内N-甲基-D-天门冬氨酸(NMDA)受体表达，以及成年期认知功能和惊厥阈的长期影响。方法：生后6d(用P6表示，下同)的Wistar大鼠随机分成两组，每组6只，惊厥组每日吸入三氟乙醚诱导惊厥发作1次，每次持续30min，连续6d；对照组同样操作但不吸入三氟乙醚。两组大鼠于P60-P65行Morris水迷宫实验，检测大鼠的学习记忆功能。于P75时给予大鼠腹腔注射戊四唑(PTZ)测定大鼠的惊厥阈。随即断头处死大鼠，分离大脑皮质和海马，匀浆提取细胞膜蛋白，应用免疫印记法测定NMDA受体亚基l(NRl)和NR2A-2D表达的变化。结果：从P6l至P65，两组大鼠寻找平台时间均逐渐缩短，惊厥组大鼠在P65的平均寻找平台时间较对照组显著延长。惊厥组大鼠注射PTZ后发生惊厥的潜伏期与对照组比较差异无显著性。在大脑皮层，惊厥组大鼠较对照组NRl和NR2B表达水平明显下调，在海马这两种亚基表达水平无明显改变，在大脑皮层和海马区，惊厥组较对照组NR2A表达水平明显下调，NR2C表达水平明显上调。两组在皮层和海马均无NR2D表达。结论；新生大鼠反复惊厥可导致远期认知障碍，同时伴有NMDA受体的数量和结构上的长期改变，NMDA受体表达的这种改变可能在发育期惊厥导致的脑长期认知功能损害中起重要作用。     

Multimodal, Multidimensional Models of Mouse Brain

Summary:  Naturally occurring mutants and genetically manipulated strains of mice are widely used to model a variety of human diseases. Atlases are an invaluable aid in understanding the impact of such manipulations by providing a standard for comparison and to facilitate the integration of anatomic, genetic, and physiologic observations from multiple subjects and experiments. We have developed digital atlases of the C57BL/6J mouse brain (adult and neonate) as comprehensive frameworks for storing and accessing the myriad types of information about the mouse brain. Along with raw and annotated images, these contain database management systems and a set of tools for comparing information from different techniques and different animals. Each atlas establishes a canonical representation of the mouse brain and provides the tools for the manipulation and analysis of new data. We describe both these atlases and discuss how they may be put to use in organizing and analyzing data from mouse models of epilepsy.     

Comparing diffusion-weighted and T2-weighted MR imaging for the quantification of infarct size in a neonatal rat hypoxic–ischemic model at 24 h post-injury

PURPOSE: In a neonatal rat model of hypoxic-ischemic (HI) brain injury, using T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI), we aim to determine the best MRI method of lesion quantification that reflects infarct size. MATERIALS AND METHODS: Twenty 7-day-old rats underwent MRI 24h after HI brain injury was induced. Lesion size relative to whole brain was measured using T2WI and apparent diffusion coefficient (ADC) maps, applying thresholds of 60%, 70% and 80% contralateral control hemisphere mean ADC, and at day 10 post-HI on pathology with TTC staining. Multiple linear regression analysis was used to study the relationships between lesion size at MRI and pathology. RESULTS: Lesion size measurement using all MRI methods significantly correlated with infarct size at pathology; using T2WI, r=0.808 (p<0.001), using 80% ADC, 70% ADC and 60% ADC thresholds, r=0.888 (p<0.001), 0.761, (p<0.001) and 0.569 (p=0.014), respectively. Eighty percent ADC threshold was found to be the only significant independent predictor of final infarct volume (adjusted R(2)=0.775). CONCLUSION: At 24h post-HI, lesion size on DWI, using 80% ADC threshold is the best predictor of final infarct volume. Although T2WI performed less well, it has the advantage of superior spatial resolution and is technically less demanding. These are important considerations for experiments which utilize MRI as a surrogate method for lesion quantification in the neonatal rat HI model.     

新生儿泪囊炎治疗的护理观察

目的:观察庆大霉素针行泪道探通冲洗疗效.方法:新生儿泪囊炎58例,其中男 40例,女 18例年龄2月至9个月用庆大霉素针4万单位加生理盐水4ml行泪道探通冲洗,次日再冲洗一次,结果:显效率为72%,有效率为26%,总有效率为98%.结论:庆大霉素针治疗新生儿泪囊炎疗效好.     

Developmental changes in intracellular pH buffering power in smooth muscle

 Intracellular pH (pH_i) is known to modulate contraction. Neonatal tissues can differ from adult tissue in contractile response to stimuli known to alter pH_i e.g. hypoxia. Changes of pH are attenuated by buffering, thus any difference in buffering power (β) between tissues could affect their functional response to pH_i perturbation. Similarly the extent to which any extracellular pH (pH_o) alteration is transmitted into a pH_i change will also influence function. We have therefore determined the intrinsic β and effect of pH_o change on pH_i in neonatal and adult ureteric, uterine and gastric smooth muscles using the pH-sensitive fluorophore carboxy-SNARF. β was found to be similar in the three adult tissues, but there were significant differences between neonatal tissues. In contrast, we found little difference in the amount of pH_i change produced by pH_o change between neonatal and adult tissues from the same smooth muscle, but a difference between smooth muscles. These data highlight significant differences between smooth muscles and their developmental state, which may contribute to different degrees of protection when pH is perturbed. Received: 17 October 1997 / Received after revision: 27 November 1997 / Accepted: 28 November 1997     

Acute toxicity of two pyrethroids,permethrin, and cypermethrin in neonatal and adult rats

The present study aims specifically at obtaining a comparison of the acute toxicity of cypermethrin (CY), a type I pyrethroid, and permethrin (PERM), a type II pyrethroid, administered orally as a single dose to neonatal and adult rats, and at assessing the importance of pyrethroid biotransformation in CY and PERM toxicity through use of drug metabolism inhibitors. Our experiments show that CY is more toxic than PERM to adult and neonatal rats. The sensitivity of neonatal rats both to CY and to PERM toxicity is higher, the younger the animals. CY is much more toxic than PERM in the neonatal rat, compared with the adult. In rats aged 8, 16, and 21 days, pretreatment with piperonil butoxide (PB), a monooxygenase inhibitor, or with tri-o-tolyl phosphate (TOTP), an esterase inhibitor, does not produce significant variations in the lethal effects of CY and PERM. Instead, in the adult rats, a significant increase in CY (X²=5.97;p<0.05) and PERM (X²=4.37;p<0.05) mortality occurred in rats pretreated with esterase inhibitors, whereas no increase in CY and PERM toxicity was found in adult animals pretreated with monooxygenase inhibitor. It was concluded that the higher level of sensitivity of the neonate rat to pyrethroid toxicity is probably due to incomplete development of the enzymes which catalyze the metabolism of pyrethroids in the liver of young animals. It is suggested that ester hydrolysis is an important pyrethroids detoxification reaction in the adult rat.     

Role of noradrenergic hyperactivity in neonatal opiate abstinence

Despite the existence of a well-defined abstinence syndrome in offspring of opiate-dependent mothers, the mechanisms involved in neonatal abstinence remain unclear. The goal of the present study was to determine the contribution of noradrenergic neurons in the opiate abstinence syndrome in neonatal rats (10 days old). First, the ability of the α2-adrenergic agonist, clonidine to attenuate the symptoms of neonatal opiate abstinence precipitated by naloxone was determined. Secondly, the activity of noradrenergic neurons was determined by measuring postmortem levels of 3-methoxy-4-hydroxyphenylglycol (MHPG) in the hypothalamus, hippocampus and cortex in opiate-abstinent pups. Neonatal opiate abstinence was characterized by an increased incidence of wall climbing, tremors and mouthing. Acute treatment with morphine and naloxone in chronic saline-treated pups also produced the tremor, albeit less severe than in pups treated chronically with morphine. Clonidine (0.2 mg/kg) attenuated the expression of tremor and mouthing in neonates, but increased wall climbing. Clonidine elicited wall climbing in opiate-naive neonates. Treatment with morphine followed by naltrexone increased MHPG levels in all of the brain areas examined, irrespective of the chronic treatment, but naltrexone treatment elicited a larger increase in MHPG levels in pups treated chronically with morphine. Acute morphine treatment increased MHPG levels only in the hypothalamus. The results of the present study provide behavioral and neurochemical data supporting the hypothesis that noradrenergic hyperactivity plays a role in neonatal opiate abstinence.     

第二产程时限与新生儿结局的关系

目的探讨第二产程时限对新生儿预后的影响。方法将216例单胎、足月、无阴道分娩禁忌证的初产妇按照第二产程持续时间(t)分为4组,比较4组间新生儿结局情况。结果手术产率、脐动脉酸血症发生率及新生儿转入新生儿加强监护病房(NICU)的发生率在t>90 m in组明显高于t≤30m in组、3090 m in,新生儿不良结局发生率增加,故应重视和积极处理第二产程。     

肝素对患感染性疾病的新生儿组织因子途径抑制物影响的观察

目的:观察肝素对患感染性疾病的新生儿组织因子途径抑制物(TFPI)的影响。方法:采用酶联免疫吸附试验(ELISA)法检测了32例患感染性疾病的新生儿在使用肝素前和使用肝素后30～45分钟、6小时血浆TFPI的变化,并与患儿对照组、正常对照组及文献进行比较。结果:患儿治疗组使用肝素后30～45分钟血浆TFPI水平明显增高(t=3.953,P<0.001),6小时血浆TFPI又几乎降至用药前水平(t=0.141,P<0.05)。结论:新生儿对肝素的反应与成人不同。     

Surgical Treatment of an Early Epileptic Encephalopathy with Suppression-Bursts and Focal Cortical Dysplasia

Summary: A case of early epileptic encephalopathy (EIEE) with suppression-bursts or Ohtahara's syndrome, associated with focal cortical dysplasia is reported. Infantile spasms and brief tonic unilateral seizures began on the fifth day of life. Interictal EEG demonstrated an asymmetrical "suppression-burst" pattern with no wake or sleep cycling. Seizures were refractory to all antiepileptic drug (AED) and steroid therapy. Magnetic resonance imaging (MRI) showed right frontotemporal cortical thickening. After three weeks of an ineffective medical treatment a preoperative evaluation with single photon emission computed tomography (SPECT) and electrocorticography (ECoG) was performed to characterize epileptogenic focus. Surgical resection of the precentral area was performed at age 1 month. Neuropathologic examinations confirmed diagnosis of focal cortical dysplasia by identifying cytoarchitectural disarray and ectopic neurons located deep in subcortical white matter. During follow-up, 1-year postoperative the child had a single febrile seizure. Neurologic examination showed minor developmental delay and slight left-sided weak ness.