不同频率及功率密度毫米波辐射对子代学习记忆功能及脑胆碱能-M受体的影响

为阐明毫米波对胚胎产生损伤效应的阈值及导致成年子鼠学习记忆功能降低的机理，验证毫米波有无频率特异性。用３７．４～６０ＧＨｚ，功率密度１ｍＷ／ｃｍ２～８ｍＷ／ｃｍ２毫米波，在小鼠怀孕６ｄ～１５ｄ时进行２ｈ／ｄ辐射，用电迷宫对成年子鼠进行学习记忆功能测试，用受体放射配基结合分析（ＲＢＡ）对子鼠脑胆碱能－Ｍ受体（Ｍ－Ｒ）进行测定。结果显示：３７．４，４２．２ＧＨｚ毫米波，≥５ｍＷ／ｃｍ２辐射可导致成年子鼠学习记忆功能降低，成年子鼠海马区Ｂｍａｘ明显升高；５３，６０ＧＨｚ毫米波，≥３ｍＷ／ｃｍ２辐射可导致成年子鼠学习记忆功能降低，成年子鼠海马区Ｂｍａｘ明显升高。毫米波辐射未使孕鼠肛温及辐射区皮肤温度明显升高。认为：３７．４，４２．２ＧＨｚ和５３，６０ＧＨｚ毫米波导致胚胎损伤阈值分别在３ｍＷ／ｃｍ２～５ｍＷ／ｃｍ２和１ｍＷ／ｃｍ２～３ｍＷ／ｃｍ２，其导致子鼠学习记忆功能降低与使成年子鼠海马区胆碱能神经活性下降相关，此效应由毫米波非热效应所致，未见毫米波的频率特异性。     

毫米波辐射孕鼠对仔代的影响

为阐明毫米波导致仔鼠学习记忆功能降低机制，用３７．４ＧＨｚ￣６０ＧＨｚ、１ｍＷ／ｃｍ＾２￣８ｍＷ／ｃｍ＾２毫米波在小鼠怀孕６￣１５天进行２ｈ／ｄ辐射，用电迷宫对仔鼠进行学习记忆功能测试，用ＲＢＡ、ＨＰＬＣ－ＥＣＤ及ＲＩＡ对仔鼠脑Ｍ－Ｒ、单胺递质和ＡＶＰ进行测定。结果显示：随功率密度增加，辐射导致仔鼠学习记忆功能损伤程度加重、脑内ＡＶＰ及ＤＡ水平递减、海马区Ｂｍａｘ递增，５３ＧＨｚ及６０ＧＨｚ辐射导     

药物对缺氧细胞内钙离子浓度的影响

目的　比较三磷酸腺苷（ Ａ Ｔ Ｐ） 、三磷酸腺苷－ 氯化镁（ Ａ Ｍ） 、异搏停（ Ｖ Ｅ Ｒ） 和超氧化物歧化酶（ Ｓ Ｏ Ｄ） 防止细胞 Ｈ／ Ｒ 损伤时４５ Ｃａ 内流的效果。方法　应用人类小肠上皮细胞缺氧－ 再给氧（ Ｈ／ Ｒ） 模型及同位素示踪方法。结果　 Ａ Ｔ Ｐ、 Ａ Ｍ、 Ｖ Ｅ Ｒ 和 Ｓ Ｏ Ｄ 均可显著减少４５ Ｃａ 内流量,前３ 组细胞内４５ Ｃａ 含量低于 Ｓ Ｏ Ｄ 组。结论　 Ａ Ｔ Ｐ、 Ａ Ｍ、 Ｖ Ｅ Ｒ 和 Ｓ Ｏ Ｄ 均具有维持细胞钙稳态作用, Ｓ Ｏ Ｄ 效果逊于其它３ 组药物。     

中度高原地区正常及妊高征孕妇超氧化物歧化酶和丙二醛水平的初步研究

本文测定了未孕妇女、正常孕妇和妊高征孕妇的超氧化物歧化酶（ＳＯＤ），丙二醛（ＭＤＡ）和维生素Ｅ（ＶＥ）水平。结果为正常孕妇ＳＯＤ低于未孕妇女，而ＭＤＡ和ＶＥ高子未孕妇女（Ｐ均＜０．０１），提示孕妇抗氧化能力可能增强。妊高征孕妇与正常孕妇相比，ＳＯＤ、ＶＥ更低（Ｐ＜０．０１），而ＭＤＡ则更高（Ｐ＜０．０５），而且妊高征孕妇的ＭＤＡ与ＳＯＤ、ＭＤＡ与ＶＥ呈负相关（ｒ＝－０．９５６，－０．７０４８、Ｐ＜０．０５），提示可能有脂质过氧化反应的增强和氧化能力下降，为妊高征的急性动脉硬化提供了条件。     

帕金森病的神经心理学测验和SPECT对照研究

研究神经心理学测验和脑ＳＰＥＣＴ对帕金森病（ＰＤ）的诊断价值。材料和方法：对３０例正常老人（ＮＡ）和３１例ＰＤ进行神经心理学测验（ＭＭＳＥ,ＦＯＭ,ＤＳＴ,ＲＶＲ,ＢＤ）和ＳＰＥＣＴ检查,比较两组认知功能和脑血流灌注特点。结果：两组间各测验（ＭＭＳＥ,ＦＯＭ,ＤＳＴ,ＲＶＲ,ＢＤ０结果均有显著差异,ＮＡ各测验是分均高于ＰＤ。与ＮＡ相比,ＰＤ双侧项叶、颞叶、基底节、丘脑的放射性计数比值显著降低（Ｐ〈     

瓣膜病人围术期血液动力学监测

通过超声心动图、右心导管及Ｓｗａｎ－Ｇａｎｚ导管检查,对２４例心脏瓣膜替换病人进行了多项血液动力学监测。结果提示：（１）术前ＭＶＲ组ＭＰＡＰ、ＰＣＷＰ和ＰＶＲ显著高于ＡＶＲ组,ＭＶＲ组ＣＩ显著低于ＡＶＲ组,ＤＶＲ组介于两者之间或无显著差异。（２）ＭＶＲ、ＡＶＲ和ＤＶＲ组术后当日ＣＩ与ＳＶＲ呈负相关,ＭＶＲ组术后８ｈＣＩ与ＣＶＰ呈正相关。文章对上述变化的原因作了简单分析。     

毫米波频率特异性的研究

目的　确定毫米波是否具有频率特异性。方法　用 37.4,42 .2 ,5 3,6 0GHz ;1,3,5 ,8mW /cm2 毫米波在小鼠怀孕 6～ 15d时进行 2h/d辐射 ,分别用HPLC ECD ,RIA及RBA对仔鼠脑单胺递质、AVP和M R进行测定 ,用Y 型电迷宫对成年子鼠进行学习记忆功能测试。结果　较高频率毫米波辐射对胚胎的损伤效应较低频率毫米波辐射为重。结论　未见毫米波的频率特异性。     

海拔4300m世居藏族和移居汉族青年氧自由基代谢对比研究

目的：探讨高原世居藏族和移居汉族青年体内自由基代谢的差异;方法：对世居西藏阿里地区的２０名藏族士兵和移居该地区的２０名汉族士兵检测红细胞压积（ＨＣＴ）、红细胞超氧化物歧化酶（ＲＢＣ－ＳＯＤ）、丙二醛（ＭＤＡ）、全血和血浆谷胱甘肽过氧化物酶（ＧＨＳ－ＰＸ）、维生素Ｃ（Ｖｃ）和维生素Ｅ（ＶＥ）的活性或含量;结果：世居藏族青年ＲＢＣ－ＳＯＤ、血浆ＧＨＳ－ＰＸ活性和ＶＥ含量均高于移居汉族青年（Ｐ〈０．０１     

PERIPHERAL NERVE REPAIR IN RATS USING VASCULARIZED FROZEN IN-SITU MUSCLE AUTOGRAFT

ＰＥＲＩＰＨＥＲＡＬＮＥＲＶＥＲＥＰＡＩＲＩＮＲＡＴＳＵＳＩＮＧＶＡＳＣＵＬＡＲＩＺＥＤＦＲＯＺＥＮＩＮ┐ＳＩＴＵＭＵＳＣＬＥＡＵＴＯＧＲＡＦＴＷＡＮＧＹａｎ（王岩）１，ＺＨＵＳｈｅｎｇ－ｘｉｕ（朱盛修）１，ＨＵＮＧＬＫ２，ＬＥＵＮＧＰＣ２１．Ｄｅｐ...     

INTRADURAL HERNIATION OF LUMBAR INTERVERTEBRAL DISC：ARE－PORTOFSEVENCASESANDDISCUSSIONOFTHEPATHOLOGICALMEC

ＩＮＴＲＡＤＵＲＡＬＨＥＲＮＩＡＴＩＯＮＯＦＬＵＭＢＡＲＩＮＴＥＲＶＥＲＴＥＢＲＡＬＤＩＳＣ：ＡＲＥ－ＰＯＲＴＯＦＳＥＶＥＮＣＡＳＥＳＡＮＤＤＩＳＣＵＳＳＩＯＮＯＦＴＨＥＰＡＴＨＯＬＯＧＩＣＡＬＭＥＣＨ－ＡＮＩＳＭＬｉａｎＰｉｎｇ连平ＳｕｎＲｏｎｇ－...     

Neuroimaging in posttraumatic hypopituitarism

Posttraumatic hypopituitarism is the failure of the hypothalamic-pituitary axis secondary to traumatic brain injury. It can clinically present as decreased muscle mass, concentration, libido, and fertility. It can also present as increased fatigue, depression, and cognitive deficits. In addition, electrolyte abnormalities such as hyponatremia can occur in hypopituitarism. As a result of heightened awareness of posttraumatic hypopituitarism, it is a phenomenon that is becoming more commonly diagnosed. Posttraumatic hypopituitarism is a diagnosis based on clinical evaluation, laboratory testing, and neuroimaging. Of the radiological techniques, magnetic resonance imaging is the preferred technique to image the pituitary gland. This article contains coronal and sagittal magnetic resonance imaging of the posterior fossa, illustrating the normal hypothalamus and pituitary gland as well as adjacent structures. The sequential enhancement pattern of the normal pituitary gland is consistent with its vascular supply. A colored illustration was created to display the vascular supply to the hypothalamus, pituitary stalk, and pituitary gland.     

高压氧治疗颅脑伤时下丘脑生长抑素和精氨酸加压素神经元的变化

目的 观察生长抑素（SS）和精氨酸加压素（AVP）在高压氧（HBO）治疗颅脑伤时的变化及可能的作用机制。方法 建立颅脑伤模型并用HBO进行治疗，采用SS原位杂交和AVP免疫细胞化学双标法进行观察。结果 颅脑伤时下丘脑室周核SS神经元减少，SS－mRNA表达下降。在视上核SS与AVP共存的阳性神经元数目减少，经HBO治疗则明显增多。结论 颅脑伤时及时给予HBO治疗，有利于神经元的恢复，进而促进SS与AVP的镇痛作用。     

Neuroimaging of central diabetes insipidus—when,how and findings

Central or neurogenic diabetes insipidus (CDI) is due to deficient synthesis or secretion of antidiuretic hormone (ADH), also known as arginine vasopressin peptide (AVP). It is clinically characterised by polydipsia and polyuria (urine output >?30 mL/kg/day) of dilute urine (<?250 mOsm/L). It is the result of a defect in one of more sites involving the hypothalamic osmoreceptors, supraoptic or paraventricular nuclei of the hypothalamus, median eminence of the hypothalamus, infundibulum or the posterior pituitary gland. A focused MRI pituitary gland or sella protocol is essential. There are several neuroimaging correlates and causes of CDI, illustrated in this review. The most common causes are benign or malignant neoplasms of the hypothalamic-pituitary axis (25%), surgery (20%), head trauma (16%) or familial causes (10%). No cause is identified in up to 30% of cases. Knowledge of the anatomy and physiology of the hypothalamo-neurohypophyseal axis is crucial when evaluating a patient with CDI. Establishing the aetiology of CDI with MRI in combination with clinical and biochemical assessment facilitates appropriate targeted treatment. The aim of the pictorial review is to illustrate the wide variety of causes of CDI on neuroimaging, highlight the optimal MRI protocol and to revise the detailed neuroanatomy and neurophysiology required to interpret these studies.     

T1 signal intensity and height of the anterior pituitary in neonates: correlation with postnatal time

BACKGROUND AND PURPOSE: The anterior pituitary of a term neonate is usually hyperintense on T1-weighted MR images, which may represent histologic changes of the gland due to the effect of high estrogen levels during the fetal period; however, MR findings of a preterm neonate have not been fully evaluated. The purpose of this study was to investigate whether intensity and size of the neonatal anterior pituitary on MR images obtained near term of corrected age correlates with the gestational age at birth or postnatal time.MATERIALS AND METHODS: Data of 88 consecutive neonates (gestational age, 24–41 weeks; mean, 31.5 weeks) were analyzed. All of the neonates underwent MR imaging at a corrected age of 0 months ± 4 weeks. Relative signal intensity of the anterior pituitary compared with that of the pons on T1-weighted sagittal images was calculated. Height of the pituitary was also measured. Stepwise regression analysis was performed to evaluate the effects of gestational age at birth and postnatal time on the relative signal intensity and on the pituitary height.RESULTS: The relative signal intensity significantly negatively correlated with postnatal time (P = .001) but not with gestational age at birth (P = .42). Pituitary height significantly negatively correlated with postnatal time (P = .049) but not with gestational age at birth (P = .071).CONCLUSION: A significant negative correlation exists between postnatal time and signal intensity on T1-weighted MR images of the anterior pituitary obtained near term. A nonhyperintense anterior pituitary is a normal MR finding of preterm neonates when imaged near term.

Several MR studies have revealed changes in size, shape, and intensity of the neonatal anterior pituitary gland.^1–5 The anterior pituitary usually shows bright signal intensity on T1-weighted MR images in term neonates.^1–3 This bright signal intensity is known to be seen only in early infancy and begin to disappear from approximately 2 months after birth.^2,3 After the first few months, the gland displays the appearance of an adult gland.^1–3,6 To the best of our knowledge, MR findings of a preterm neonate have not been fully evaluated.Several histologic analyses of the human fetal anterior pituitary gland have been reported.^7–9 Asa et al⁷ reported that, after gestational week 25, the most significant change in histology of the anterior pituitary is an increase in prolactin-containing cells. van Nesselrooij et al¹⁰ clarified that the pituitary of a rat that had received estrogen developed hyperplasia of prolactin cells, and MR imaging detected enlargement of the gland.¹⁰ Kovacs and Horvath¹¹ stated that, due to the effect of maternal estrogen, prolactin cells are numerous in the fetus and neonate, decreasing after birth and remaining low during childhood. These reports suggest that estrogen may be 1 of the key hormones in maturation of the anterior pituitary gland in pregnancy.The placenta is the principal source of increases in steroids, estrogens, and progesterone during pregnancy.^12,13 From the perspective of the period under the effect of estrogen produced by placenta, some histologic differences in the anterior pituitary may present due to the duration of pregnancy.We hypothesized that gestational age at birth and intensity of the anterior pituitary on MR images obtained near term of corrected age may be positively correlated and/or that postnatal time (elapsed time between birth and the MR examination) and intensity of the anterior pituitary may be negatively correlated, because neonates with a shorter gestational period have a shorter period under the effects of estrogen during the fetal period and a longer period after removal of the influence of placental estrogen. The purpose of this study was to reveal whether intensity and size of the neonatal anterior pituitary on MR images obtained near term of corrected age correlates with the gestational age at birth or postnatal time.     

Simultaneously avoiding the hippocampus and hypothalamic-pituitary axis during whole brain radiotherapy: A planning study

Whole brain radiotherapy (WBRT) is the preferred treatment for multiple brain metastases, and patients with limited-stage small cell lung cancer undergo prophylactic cranial irradiation after complete remission. However, neurotoxicity remains a complication. In addition to protecting the hippocampus from irradiation to preserve cognitive function, it is also critical to avoid irradiating the hypothalamic-pituitary axis to preserve endocrine and immune function. This study aimed to evaluate the feasibility of delivering WBRT while protecting the hippocampus and hypothalamic-pituitary axis. Thirteen patients with limited-stage small cell lung cancer were enrolled in this study. The hippocampus, hypothalamus, and pituitary gland were contoured based on T1-weighted magnetic resonance imaging. The prescribed dose to the whole brain planning target volume was 25 Gy in 10 fractions. Two treatment plans using equispaced coplanar intensity-modulated radiotherapy (IMRT) were generated: WBRT with hippocampus avoidance (H-A) and WBRT with hippocampus, hypothalamus, and pituitary gland avoidance (H-HP-A). Both “H-A” and “H-HP-A” plans successfully protected the hippocampus, which received mean doses of 9.1 and 9.6 Gy, respectively (p = 0.0002), whereas the “H-HP-A” plan decreased the doses to both the hypothalamus (mean dose 11.06 Gy) and the pituitary gland (mean dose 10.66 Gy). Both “H-A” and “H-HP-A” plans showed similar target coverage of 95.1%. The homogeneity index of the “H-A” plan was slightly better than that of the “H-HP-A” plan (0.20 vs 0.23, p = 0.0012). In conclusion, the use of equispaced coplanar IMRT was found to simultaneously protect the hippocampus and hypothalamic-pituitary axis while delivering WBRT with acceptable target coverage and homogeneity.     

MR imaging of the pituitary gland in infants and children: changes in size, shape, and MR signal with growth and development.

It has been reported that on MR images of the brain in neonates the entire pituitary gland is hyperintense. This is quite different from the well-established observation that portion is isointense. To better understand the development of the neonatal pituitary gland, we studied the timing and magnitude of changes in the size, shape, and MR signal of the pituitary gland in early childhood and infancy. The study included 76 infants and children ages 3 days to 4 years old. In each MR study, the signal intensity of the pituitary gland on T1-weighted coronal (n = 24) and sagittal (n = 76) images was compared with the signal intensity of the pons by using region-of-interest methods. The size and shape of the pituitary glands were recorded. Statistical comparisons were made for signal intensity and size of the pituitary gland between boys and girls and among age groups. The results showed that the MR signal of the posterior lobe remained hyperintense relative to the pons for all age groups represented in our study (through 4 years). However, the signal intensity of the anterior lobe gradually diminished and by approximately age 2 months was isointense with the pons. Thus, by approximately age 2 months the MR signal intensity of the infant's pituitary gland has changed from being entirely hyperintense (as seen in neonates) to isointense in the anterior lobe and hyperintense in the posterior lobe (as seen in adults). In the first 2 months of life the pituitary gland is bulbous in shape; later it has a flatter upper surface. We found no significant changes in the length or signal intensity of the pituitary gland; no differences among sexes in size, shape, or signal intensity were demonstrated. Findings of a bulbous pituitary gland and high MR signal of the entire pituitary are normal in neonates up to 2 months of age. After that, the gland gradually flattens and the MR signal of the anterior lobe decreases until it has characteristics similar to the adult pituitary. Lack of high signal or discovery of a small pituitary gland in a neonate should alert the radiologist to the possibility of pituitary malformation or dysfunction.     

Size, shape, and appearance of the normal female pituitary gland

One hundred seven women 18-65 years old were studied who were referred for suspected central nervous system disease not related to the pituitary gland or hypothalamus. High-resolution, direct, coronal, contrast-enhanced computed tomography (CT) was used to examine the size, shape, and density of the normal pituitary gland. There were three major conclusions: (1) the height of the normal gland can be as much as 9 mm; (2) the superior margin of the gland may bulge in normal patients; and (3) both large size and convex contour appear to be associated with younger age. It was also found that serum prolactin levels do not appear to correlate with the CT appearances. Both low- and high-density areas were seen within the gland, and may be due to either tumors, cysts, infarcts, or metastases. Noise artifacts inherent in high-detail, thin-section, soft-tissue scanning may be a limiting factor in defining reproducible patterns in different parts of the normal pituitary gland.     

Histiocytosis mimicking a pineal gland tumour

We report an unusual case of isolated Langerhans cell histiocytosis of the central nervous system. A 19-year-old man presented with an incomplete ocular palsy. MRI revealed a solitary mass in the pineal gland with marked contrast enhancement. Complete microsurgical excision was followed by local radiotherapy. Histological examination revealed histiocytosis. Unifocal brain involvement by histiocytosis X is rare with few cases in the literature; the most commonly involved areas are the hypothalamus and the pituitary gland. Received: 21 July 2000 Accepted: 21 December 2000