Light and electron microscopic immunocytochemistry of GRF-like immunoreactive neurons and terminals in the rat hypothalamic arcuate nuclues and median eminence

Growth hormone-releasing factor (GRF) synthesizing neuronal perikarya and terminals were investigated by light and electron microscopic immunocytochemistry using rat hypothalamus. Immunoreactive neuronal perikarya were located mainly in the ventrolateral part of the arcuate nucleus. They contained well developed cell organella such as mitochondria and rough surfaced endoplasmic reticulum with some expansion. They also contained immunoreactive dense granules (80-120 nm in diameter). On the surface of the immunoreactive neuronal perikarya were frequently found non-immunoreactive axo-somatic synapses. Therefore, the GRF-like immunoreactive neurons were assumed to receive neuronal inputs from other neurons on their neuronal soma. In the external layer of the median eminence large numbers of immunoreactive terminals were distributed particularly around the capillaries of the portal vessel. Electron microscopic immunocytochemistry revealed large numbers of immunoreactive terminals containing immunoreactive dense granules, synaptic vesicles and mitochondria in the vicinity of the basement membrane of the pericapillary space of the portal vessel. Therefore, we concluded that GRF-like immunoreactive substances are released into the portal capillaries from the nerve terminals, which originate from the neuronal perikarya in the ventrolateral part of the arcuate nucleus, and act on growth hormone release in the anterior pituitary. We also suggest that GRF-like immunoreactive neurons have abundant terminal arborization in the external layer of the median eminence.     

Efficacy evaluation of gadoteridol for MR angiography of intracranial vascular lesions

A phase III multicenter study was conducted in 89 patients with known intracranial vascular lesions to evaluate an extracellular gadolinium contrast agent, gadoteridol, for intracranial magnetic resonance (MR) angiography. The pre- and postcontrast MR angiograms of 82 patients were evaluated by the unblinded investigators and by two blinded readers (A and B) for visualization of lesions; arterial and venous anatomy; extent, size, and number of lesions; and disease classification. The unblinded readers indicated that lesions were visualized better on postcontrast images in the following categories: venous anatomy, 87 (81%) of 107 lesions; arterial anatomy, 43 lesions (40%); and extent or size of lesions, 38 lesions (36%). In 29 (35%) of 82 patients, the unblinded readers determined that enhanced MR angiography provided more diagnostic information than unenhanced MR angiography. The blinded readers determined that enhanced MR angiography provided more information for visualization of vascular anatomy in more than 60% of cases. The additional information provided with gadoteridol would have changed the diagnosis in nine (8%) of 107 lesions seen by the unblinded readers, 11 (12%) of 90 lesions seen by reader A, and three (3%) of 93 lesions seen by reader B. The results confirm that the use of gadoteridol improves the visualization of intracranial vascular lesions with MR angiography. The authors conclude that development of new postprocessing algorithms will improve the utility of contrast-enhanced MR angiography.     

Raymond's syndrome following petrosal sinus sampling

Summary Inferior petrosal sinus sampling (IPSS) is used to evaluate the pituitary-dependency of Cushing's disease, and to predict the laterality of a microadenoma prior to transsphenoidal operation. A serious complication occured in a 14-year-old boy: he suffered brain stem ischaemia with abducens nerve palsy and hemiparesis (Raymond's syndrome). The case prompted us to reconsider the indication for this investigation.     

流行性出血热危险因素的病例对照研究

用病例对照研究方法探索建德县罹患流行性出血热(EHF)的危险因素。经临床诊断和血清学证实的97例EHF病例,按年龄、性别和住同一医院与其他疾病病人作1:1配对调查。条件logistic回归模型分析,发现村中曾有EHF史、外出他县、野宿和直接接触鼠类四个因素是罹患EHF的危险因素,其相对危险度分别为35.67、11.94、18.18和7.36。病例家属隐性感染率(4.95％)与对照家属隐性感染率(5.12％)相似;病例与对照家中捕获的鼠类及其EHF抗体、抗原阳性率无显著性差异。     

神经活素对Pc12细胞作用的初步观察

从胎脑、颌下腺、肌肉组织中制备神经活素。其性能同脑活素一样：可促进Ｐｃ１２细胞的突起生长，提高其胞浆内乳酸脱氢酶活性，电泳显示二者有相同的三条带。提示：神经活素有可能替代脑活素应用于临床。     

生物医学测量及控制技术新进展

介绍生物医学测量及控制技术领域中的一些研究进展。     

Plasma volume estimation using indocyanine green with biexponential regression analysis of the decay curves

We studied seven analytical methods of estimating the plasma volume from the decay curves of indocyanine green. Fifteen volunteers received 1.0 mgkg⁻¹ of the dye by intravenous injection and the plasma concentration was measured continuously using spectrophotometry. Plasma volumes were calculated using three single-regression methods (1-a, 1-b, 1-c) and four biexponential regression methods (2-a, 2-b, 2-c, 2-d). The means (SD) of 1-a, 1-b and 1-c were 39 (5.0), 44 (5.7) and 54 (11.5) mlkg⁻¹, respectively, and these were significantly different from each other (p < 0.05). The values for methods 2-b, 2-c and 2-d were similar to each other: 39 (4.6), 40 (4.1) and 40 (4.0) mlkg⁻¹, respectively. These required more than 3 min circulation or mixing time. When the time allowed for mixing was less than 3 min (method 2-a) the plasma volume was underestimated. We conclude that plasma volume estimation using indocyanine green and spectrophotometry is most accurate when the mixing time is adequate (3–5 min) and the decay curves are analysed using biexponential regression.     

Dynamic MRI of the gallbladder lesions: Differentiation of benign from malignant

Forty-nine pathologically proven gallbladder lesions were evaluated in 45 patients using dynamic MRI with a spoiled gradient pulse sequence (SPGR), to access the ability of this technique to differentiate benign from malignant gallbladder lesions. The studies were reviewed retrospectively. Signal intensity of the lesions were measured. Twenty-one malignant and 28 benign lesions were classified into three categories: polypoid, diffuse wall thickening, and exophytic. Early and delayed enhancement patterns were evaluated. For the polypoid masses, malignant lesions (n = 9) demonstrated early and prolonged enhancements, whereas benign lesions (n = 14) had early enhancement with subsequent washout (P < .05). For diffuse gallbladder wall thickening, malignant lesions (n = 6) demonstrated early and prolonged enhancement and benign lesions (n = 14) showed relatively slow, prolonged enhancement (P < .05). The exophytic masses (n = 6) all were malignant and demonstrated early and prolonged enhancement. Dynamic MRI can help differentiate benign from malignant gallbladder lesions.