次声刺激后大鼠下丘神经型一氧化氮合成酶阳性神经元FOS蛋白的表达

目的　研究次声对下丘的作用机制。方法　用抗 Ｆ Ｏ Ｓ 蛋白和抗神经型一氧化氮合成酶（ｎｃ Ｎ Ｏ Ｓ） 免疫组织化学方法,将大鼠暴露于８ Ｈｚ 、１２０ ｄ Ｂ 的次声中,持续２ 小时,观察下丘 Ｆ Ｏ Ｓ 蛋白的表达情况及其与ｎｃ Ｎ Ｏ Ｓ 阳性神经元的关系。结果　在下丘出现大量 Ｆ Ｏ Ｓ 样及散在的ｎｃ Ｎ Ｏ Ｓ 样免疫反应阳性神经元,且部分ｎｃ Ｎ Ｏ Ｓ阳性神经元的胞核同时呈 Ｆ Ｏ Ｓ 染色阳性,这种 Ｆ Ｏ Ｓ／ｎｃ Ｎ Ｏ Ｓ 双标记神经元约占 Ｆ Ｏ Ｓ 阳性神经元总数的１０ ％ 。结论　部分ｎｃ Ｎ Ｏ Ｓ 神经元参与对次声刺激的反应。     

NMDA受体Ⅰ及白细胞介素-1在癫痫机制中的作用

应用北京医科大学培育的听源性癫痫易感大鼠Ｐ７７ＰＭＣ,以癫痫不易感大鼠Ｗｉｓｔａｒ为对照,系统研究了ＮＭＤＡ受体亚单位Ⅰ（ＮＲ１）与白细胞介素１（ＩＬ１）在癫痫发生发展中的作用及相互关系。实验在整体、脑片、神经细胞培养及分子水平进行。所得较有意义的结果如下：（１）在听源性惊厥易感大鼠Ｐ７７ＰＭＣ整个发育过程中脑内ＮＲ１ｍＲＮＡ的表达,以及成年鼠脑内ＮＭＤＡ受体活性（ＭＫ８０１结合）都高于对照组Ｗｉｓｔａｒ大鼠。惊厥后Ｐ７７ＰＭＣ脑内ＮＲ１ｍＲＮＡ的表达呈时间依赖性增加,惊厥后２４ｈ比惊厥前增加１１１％～２０２％;ＮＲ１反义寡核苷酸脑室注射（每μｌ１０μｇ）可显著减轻Ｐ７７ＰＭＣ大鼠惊厥程度,并可对谷氨酸引起的体外神经细胞的损伤有保护作用,抑制谷氨酸导致的神经毒性作用。由此证实ＮＲ１参与惊厥的发生发展,并与Ｐ７７ＰＭＣ大鼠的遗传性癫痫易感性关系密切。（２）在神经细胞培养中ＩＬ１β可明显剂量依赖性地（１～２５Ｕ·ｍｌ１）提高ＮＲ１ｍＲＮＡ的表达,白细胞介素１受体拮抗剂（ＩＬ１ｒａ）可阻断此效应;ＩＬ１β可剂量依赖性地提高ＮＲ１受体活性,因此提示ＩＬ１具有兴奋性神经调质的作用,其作     

小檗碱对体外培养大鼠大脑皮层神经元损伤的保护作用

体外培养大鼠胎鼠大脑皮层神经细胞,观察小檗碱（ｂｅｒｂｅｒｉｎｅ,Ｂｅｒ）对Ｎ－甲基－Ｄ－门冬氨酸（Ｎ－ｍｅｔｈｙｌ－Ｄ－ａｓｐａｒ－ｔａｔｅ,ＮＭＤＡ）、过氧化氢（Ｈ２Ｏ２）及撤血清培养引起的细胞损伤的保护作用。结果表明,培养的大鼠胚胎大脑皮层神经细胞在ＮＭＤＡ５００μｍｏｌ／Ｌ作用１０ｍｉｎ、或Ｈ２Ｏ２１００μｍｏｌ／Ｌ２４ｈ、或无血清培养４８ｈ后,细胞的死亡率及乳酸脱氢酶（ＬＤＨ）漏出率明显增加,抗氧化酶ＳＯＤ、谷胱甘肽过氧化酶（ＧＳＨ－Ｐｘ）活性显著降低,而脂质过氧化物丙二醛（ＭＤＡ）生成增多。Ｂｅｒ１０、３０μｍｏｌ／Ｌ能显著降低细胞死亡率、ＬＤＨ漏出率及ＭＤＡ的生成,且能明显提高抗氧化酶活性。提示：Ｂｅｒ可拮抗ＮＭＤＡ、Ｈ２Ｏ２及撤血清培养引起的神经细胞损伤,其机理可能与其减少膜脂质过氧化物生成,提高抗氧化酶活性有关     

Visual-evoked potential evidence of chiasmal hypoplasia

PURPOSE: To show that chiasmal hypoplasia or aplasia need not be an isolated developmental anomaly and to examine the spectrum of associated clinical findings to explore the possibility that these patients may represent a phenotypic manifestation of a developmental gene anomaly. DESIGN: An observational case series. PARTICIPANTS: Five infants, between several weeks and 7 months of age, in whom the electrophysiologic characteristic of chiasmal hypoplasia had been noted were included. METHODS: Flash electroretinography and flash and pattern visual-evoked potentials (VEPs) were elicited from all patients. Clinical ophthalmologic examinations, including funduscopy, were performed, and all patients had magnetic resonance imaging (MRI) brain scans. MAIN OUTCOME MEASURES: The occipital distribution of monocular VEP response peaks was studied. The symmetry of lateral channel responses was compared for monocular stimulation. RESULTS: All five patients had a crossed asymmetry in the monocular VEP occipital distribution, which is consistent with a paucity of fibers crossing at the chiasm. The MRI findings supported this electrophysiologic observation, illustrating degrees of chiasmal hypoplasia and variable coincidence of other midline abnormalities of the brain. Optic disc appearances varied from normal to hypoplastic and colobomatous. CONCLUSIONS: The ophthalmologic and MRI findings of five patients who showed a crossed asymmetry in monocular flash VEPs are consistent with a paucity of axons crossing at the chiasm. The similarities between achiasmia in humans and mice due to a Pax2 gene anomaly are discussed.     

Radiation exposure: a new risk factor for idiopathic perifoveal telangiectasis

Objective

To examine the association between previous radiation exposure and idiopathic perifoveal telangiectasis (IPT).

Symptomatic compression of the optic nerve by the carotid artery: clinical profile of 18 patients with 24 affected eyes identified by magnetic resonance imaging.

OBJECTIVE: To characterize the clinical features and course of patients with magnetic resonance imaging (MRI)-defined optic nerve compression by the supraclinoid carotid artery. DESIGN: Retrospective, observational case series. PARTICIPANTS: Eighteen patients with 24 affected eyes were identified by reviewing case records from the author's referral-based neuro-ophthalmology practice. Predetermined inclusion and exclusion criteria were applied to potential participants. MAIN OUTCOME MEASURES: The following variables were abstracted from the medical record: age, gender, presenting symptoms, past medical problems, visual acuity, color vision, visual field, pupillary reactions, optic disc appearance, other neurologic signs, and previously documented and follow-up examinations. RESULTS: There were eight women and ten men ranging in age from 28 to 86 years (median age, 72 years) at the time of diagnosis. Ten (56%) of 18 patients had hypertension. Twelve patients had unilateral optic neuropathy, whereas 6 patients had bilateral optic neuropathy. One patient presented with subacute superior orbital fissure syndrome due to mass effect of a dolichoectatic carotid artery. Another patient had oculomotor nerve palsy with signs of aberrant regeneration due to intracavernous mass effect of a dolichoectatic carotid artery. One patient had a bitemporal hemianopia associated with bilateral compression of the immediate prechiasmatic optic nerves by dolichoectatic carotid arteries. The predominant pattern of visual field loss in most patients reflected nerve fiber bundle injury. A central scotoma or absolute central visual field loss was noted in only 6 (25%) of 24 affected eyes. Most patients demonstrated saucerlike excavation of the optic disc. Progression of visual acuity loss occurred at a relatively slow rate. CONCLUSIONS: Although uncommon, intracranial compression of the optic nerve by the carotid artery should be considered in a patient with unexplained or progressive unilateral or bilateral optic neuropathy. This entity can be diagnosed using clinical skills to exclude more common causes of optic nerve injury and coronal-oriented MRI to confirm anatomic compression of the symptomatic optic nerve. Although many affected patients have excavation of the optic disc and nerve fiber bundle visual field defects, most have additional signs atypical for glaucoma, minimizing the potential for diagnostic confusion between the two disorders.     

Electrophysiological indices of acute effects of ethanol on involuntary attention shifting

Dose-related effects of ethanol (placebo, 0.30, and 0.60 g/kg) on behavioral and event-related brain potential (ERP) indices of involuntary attention shifting of audition were investigated. ERPs were recorded from 11 healthy social drinkers during a forced-choice reaction-time (RT) task. Subjects were presented with 100 and 200 ms tones (P = 0.50 for each) with a constant inter-stimulus interval (ISI) of 1 s. The task was to press either of two buttons, depending on the tone duration. The majority of the tones (“standards”) were of 700 Hz (P = 0.82). Occasionally, however, the frequency of the tones changed, deviating either slightly (750 Hz), moderately (900 Hz), or widely (1200 Hz; P = 0.06 for each) from the standard frequency. In accordance with previous findings, the task-irrelevant frequency deviations prolonged the RT. This RT prolongation was attenuated by alcohol with the 0.3 g/kg dose, thus suggesting less distraction by irrelevant stimulus deviations under the influence of ethanol. Furthermore, the P3a, reflecting involuntary attention shifting, was suppressed by alcohol even with the 0.3 g/kg dose. These findings demonstrate a detrimental effect of alcohol on involuntary attention shifting, evident with doses considerably smaller than previously described, and still juridically acceptable in road traffic in most countries. Received: 19 December 1997/Final version: 26 May 1998     

Barriers to follow‐up of abnormal screening mammograms among low‐income minority women

Objective. To describe factors related to compliance diagnostic follow‐up among minority women of low socioeconomic status with abnormal screening mammograms.

Methods. A retrospective cross‐sectional survey using a structured telephone interview. Three cancer screening clinics at an urban inner‐city public hospital. All women with abnormal screening mammograms between September 1990 and January 1992 were eligible; women were interviewed in August 1992. Abnormal mammograms were those requiring specific, non‐routine clinical follow‐up; non‐compliance was defined as delayed follow‐up (four to six months after the date of the mammogram), or no follow‐up at the time of interview (more than 6 months after abnormal).

Results. Sixty‐two of 442 screened women had abnormal results; the overall rate of non‐compliance with follow‐up was 50%. Among the 42 (68%) women who agreed to be interviewed, non‐compliers were less likely to state that they had been told to receive follow‐up than compilers (65% versus 100%; p = 0.008). Non‐compliant women were less likely to have suspicious mammography interpretations (p = 0.05), and more likely to report barriers to follow‐up, such as cost of lost wages and medical care, system barriers, or fears, than compliant women (61.9% versus 9%, p = 0.01). There were no differences between the two groups for age, education, insurance, source of care, family history, knowledge or attitudes.

Conclusions. These preliminary results suggest that follow‐up of low income, minority women with abnormal screening mammograms could be enhanced by improved communication of results. Future studies should extend these findings with larger samples and in other settings and populations.