An improved holder for transfer of brain slices during in vitro incubation

Summary A new type of tissue holder is described in which the slices are freely floating. Rat brain-cortex slices incubated in this holder show a potassium concentration of 70.4 moles/g final wet wt. after incubation and transfer for 1 hr.     

CT and MRI slice separation evaluation by LabView developed software

The efficient use of Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) equipment necessitates establishing adequate quality-control (QC) procedures. In particular, the accuracy of slice separation, during multislices acquisition, requires scan exploration of phantoms containing test objects. To simplify such procedures, a novel phantom and a computerised LabView-based procedure have been devised, enabling determination the midpoint of full width at half maximum (FWHM) in real time while the distance from the profile midpoint of two progressive images is evaluated and measured. The results were compared with those obtained by processing the same phantom images with commercial software. To validate the proposed methodology the Fisher test was conducted on the resulting data sets. In all cases, there was no statistically significant variation between the commercial procedure and the LabView one, which can be used on any CT and MRI diagnostic devices.     

Effects of a nitric oxide synthase inhibitor on NMDA receptor function in organotypic hippocampal cultures

Nitric oxide (NO) has been proposed to trigger long-term potentiation (LTP) at CA3 to CA1 synapses. We previously reported that NO synthesis inhibitors and blockers reduce an electrophysiological index of NMDA receptor activation in acute hippocampal slices. We now show that the NOS inhibitor, N^G-methyl-

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-arginine (MLA), also reversibly prevents LTP induction in organotypic hippocampal slices and significantly reduces a biochemical index of NMDA receptor function. These results further indicate that MLA inhibits LTP induction by interfering with NMDA receptor functions.     

Slice cultures of the imprinting-relevant forebrain area medio-rostral neostriatum/hyperstriatum ventrale of the domestic chick: immunocytochemical characterization of neurons containing Ca-binding proteins

The forebrain area medio-rostral neostriatum/hyperstriatum ventrale, a presumed analogue to the mammalian prefrontal cortex, displays a variety of synaptic changes during auditory filial imprinting. In order to study the underlying basic mechanisms of this synaptic plasticity we developed slice cultures of the medio-rostral neostriatum/hyperstriatum ventral from newly hatched chicks. As a prerequisite for these investigations and in order to test the suitability of this system for future studies, we performed a thorough characterization of the in vitro tissue, of its cellular components and some of their biochemical features in comparison with in situ tissue. Since in situ the medio-rostral neostriatum/hyperstriatum ventrale has been previously shown to contain three distinct neuron populations characterized by the activity-regulated Ca²⁺-binding proteins parvalbumin, calbindin D28K and calretinin, we used these proteins as neuronal markers to study the survival and preservation of the morphological features of medio-rostral neostriatum/hyperstriatum ventrale neurons in vitro. In agreement with in vivo studies the three Ca²⁺-binding proteins are confined to neuronal cells and they are not colocalized, i.e. they appear to characterize three different neuron populations. The immunoreactive neurons in medio-rostral neostriatum/hyperstriatum ventrale cultures to a certain extent appear to form synaptic contacts with each other, shown by the double immunocytochemical experiments. One difference between cells in vivo and in vitro is their soma size, which is much larger in vitro than in vivo. This and our previous study on neuronal morphology demonstrates that morphologically and biochemically intact neurons can be maintained in medio-rostral neostriatum/hyperstriatum ventrale slice cultures, which may thus provide a suitable in vitro system for further studies of neuronal and synaptic plasticity in vitro.     

Feasibility of diffusion-weighted imaging under split breath-hold acquisition and postprocessing (DWI-SBAP): an attempt to suppress hepatic pseudo-anisotropy

Purpose  To suppress hepatic pseudo-anisotropy, which is a specific artifact in diffusion-weighted imaging (DWI) of the liver obtained under respiratory triggering, the authors developed a novel acquisition technique for DWI that we termed “diffusion-weighted imaging under split breath-hold acquisition and postprocessing” (DWI-SBAP). We evaluated its feasibility in this study. Materials and methods  Of 113 patients whose hepatic DWI under respiratory triggering (RT-DWI) showed prominent hepatic pseudo-anisotropy, 35 were included in the study. DWI-SBAP was additionally performed in these patients. Two radiologists visually evaluated the RT-DWI and DWI-SBAP from the viewpoints of the degree of pseudo-anisotropy and the image quality of trace images of both sequences. During evaluation of the image quality of trace images, both pseudo-anisotropy and slice misregistration artifacts were taken into consideration. Results  The pseudo-anisotropy seen was significantly lower in DWI-SBAP than that in RT-DWI. Regarding visual evaluation of the trace images, the image quality of DWI-SBAP was superior to that of RT-DWI, although misregistration artifacts were observed in DWI-SBAP trace images of two patients. Conclusion  DWI-SBAP is a feasible technique for obtaining fine abdominal DWI and is effective in suppressing hepatic pseudo-anisotropy. To use this sequence in the clinical scenario, we believe it is necessary to develop a method of generating apparent diffusion coefficient maps and simultaneous use of slice tracking techniques.     

Effects of galanin receptor agonists on locus coeruleus neurons

Galanin exerts an inhibitory effect on locus coeruleus (LC) neurons via a postsynaptic, as yet unidentified galanin receptor. Using an in vitro intracellular recording technique the effect of two galanin receptor agonists on LC neurons was investigated. Bath application of [Sar(1), D-Ala(12)]gal(1-16)-NH(2) (AR-M961), an agonist both at galanin R1 and R2 (GALR1, GALR2) receptors, evoked a reversible membrane hyperpolarization and inhibition of spike discharge in all LC neurons tested (n=42). The action of AR-M961 was blocked by tetraethylammonium chloride. Hyperpolarizing responses induced by AR-M961 were retained in the presence of tetrodotoxin and high Mg(2+)/low Ca(2+) media. The selective GALR2 agonist Gal(2-11)-NH(2) (AR-M1896) only caused inhibition of spike discharge and a slight hyperpolarization in 26 of 34 LC neurons tested, and was on a molar basis much weaker than AR-M961. These results suggest that it mainly is the GALR1 receptor that mediates hyperpolarization of LC neurons.     

利用近红外光谱模型快速鉴别复方甘草片的真伪

目的:建立复方甘草片的近红外(NIR)光谱模型,利用正伪品NIR图谱的不同,对复方甘草片进行初步筛选。方法:用NIR光谱仪对待检复方甘草片进行现场扫描,通过NIR光谱图对假劣药进行初步筛选,其后通过实验室检查对结果进行复核。结果:正伪品的NIR光谱图存在较大差别。实验室检查显示薄层色谱图正品与对照品相应的位置上显相同颜色的斑点,伪品对应的位置上则不显斑点。结论:用NIR光谱模型快速筛查复方甘草片,操作简便、快速、准确,可在药品检测车中推广应用。     

128层螺旋CT双下肢动脉成像最佳重建层厚的研究

目的探讨128层螺旋CT双下肢动脉成像最佳的重建层厚。方法随机选取128层螺旋CT双下肢动脉成像40例患者的图像,分别进行0.6mm、0.75mm、1.0mm、1.5mm、2.0mm、3.0mm、5.0mm重建,比较不同重建层厚各段动脉伪影的发生率、病灶遗漏情况及去骨效果。结果①腹主动脉下段及髂动脉段血管,不同层厚的MIP图像均能显示,个别图像去骨不完全,5.0mm层厚图像病变可遗漏,病变及血管壁模糊,3.0mm以下层厚无显著性差异。②显示股浅动脉及腘动脉段2mm以下层厚的图像质量明显优于2mm以上层厚的图像。③胫前后动脉、足动脉1mm以下图像质量明显优于1.5mm以上层厚的图像。结论双下肢动脉CT造影采用1.0mm及以下层厚重建,可准确去骨,可较准确地观察各级动脉干,采用0.75mm及以下层厚可减少部分容积伪影,为节省重建时间,降低图像噪声,建议选用0.75mm层厚作为128层螺旋CT双下肢动脉成像最佳重建层厚。     

64排螺旋CT冠状动脉造影的护理配合

目的探讨护理配合在64排螺旋CT冠状动脉造影检查中的重要性。方法对281例患者行64排螺旋CT冠状动脉造影检查,进行严格的护理操作和耐心、细致的心理疏导,分析护理配合对冠脉成像图像质量的影响。结果 281例64排CT冠脉检查患者无1例渗漏,94.7%患者影像质量确认为优良,能够满足影像学诊断要求;5.3%患者扫描期间心率突然上升至70次/min以上,影像质量不能满足影像学诊断要求。结论严格的护理操作和耐心、细致的心理疏导是保证64排螺旋CT冠脉造影检查成功的关键。     

The cholinergic system and hippocampal plasticity

Acetylcholine is an essential excitatory neurotransmitter in the central nervous system and undertakes a vital role in cognitive function. Consequently, there is ample evidence to suggest the involvement of both nicotinic and muscarinic acetylcholine receptors in the modulation of synaptic plasticity, which is believed to be the molecular correlate of learning and memory. In the hippocampus in particular, multiple subtypes of both nicotinic and muscarinic receptors are present at presynaptic and postsynaptic loci of both principal neurons and inhibitory interneurons, where they exert profound bi-directional influences on synaptic transmission. Further evidence points to a role for cholinergic activation in the induction and maintenance of synaptic plasticity, and key influences on hippocampal network oscillations. The present review examines these multiple roles of acetylcholine in hippocampal plasticity.