西门子多叶光栅人工校准方法研究与实验

目的：确保多叶光栅（MLC）在放射治疗中的定位精度。方法：通过详细分析西门子Primus和Oncor加速器内置82片多叶光栅的结构组成和特点,利用现有配备的工具进行手工校准MLC。结果：定期校准MLC,减少了加速器出现联锁的机率,保证了患者治疗的顺利执行。结论：总结了一种通过手动方式校准多叶光栅的方法。该方法不需专用工具,易于操作,具有一定的可行性。     

The unsolved puzzle of neuropathogenesis in glutaric aciduria type I

Glutaric aciduria type I (GA-I) is a cerebral organic aciduria caused by deficiency of glutaryl-Co-A dehydrogenase (GCDH). GCDH deficiency leads to accumulation of glutaric acid (GA) and 3-hydroxyglutaric acid (3-OHGA), two metabolites that are believed to be neurotoxic, in brain and body fluids. The disorder usually becomes clinically manifest during a catabolic state (e.g. intercurrent illness) with an acute encephalopathic crisis that results in striatal necrosis and in a permanent dystonic-dyskinetic movement disorder. The results of numerous in vitro and in vivo studies have pointed to three main mechanisms involved in the metabolite-mediated neuronal damage: excitotoxicity, impairment of energy metabolism and oxidative stress. There is evidence that during a metabolic crisis GA and its metabolites are produced endogenously in the CNS and accumulate because of limiting transport mechanisms across the blood-brain barrier. Despite extensive experimental work, the relative contribution of the proposed pathogenic mechanisms remains unclear and specific therapeutic approaches have yet to be developed. Here, we review the experimental evidence and try to delineate possible pathogenetic models and approaches for future studies.     

Intracerebroventricular administration of inosine is anticonvulsant against quinolinic acid-induced seizures in mice: an effect independent of benzodiazepine and adenosine receptors

Inosine (INO) has an anticonvulsant effect against seizures induced by antagonists of GABAergic system. Quinolinic acid (QA) is an agonist NMDA receptors implicated in the neurobiology of seizures. In the present study, we investigated the anticonvulsant effect of intracerebroventricular (i.c.v.) INO administration against QA-induced seizures in adult mice. We also investigated whether the benzodiazepines (BZ) or adenosine (ADO) receptors were involved in the INO effects. Animals were pretreated with an i.c.v. injection of either vehicle or INO before an i.c.v. administration of 4 μl QA (36.8 nmol). All animals pretreated with vehicle followed by QA presented seizures. INO protected against QA-induced seizures in a time and dose dependent manner (up to 60% at 400 nmol, 5 min before QA injection). Diazepam (DZ) and ADO (i.c.v.) also exhibited anticonvulsant effect against QA induced seizures. Additionally, i.p. administration of either flumazenil, a BZ receptor antagonist, or caffeine, an ADO receptor antagonist, did not change the anticonvulsant potency of INO i.c.v. injection, but completely abolished the DZ and ADO anticonvulsant effects, respectively. In conclusion, this study demonstrated that INO exert anticonvulsant effect against hyperactivity of the glutamatergic system independently of BZ or ADO receptors activation.     

The Lung Image Database Consortium (LIDC): ensuring the integrity of expert-defined "truth"

RATIONALE AND OBJECTIVES: Computer-aided diagnostic (CAD) systems fundamentally require the opinions of expert human observers to establish "truth" for algorithm development, training, and testing. The integrity of this "truth," however, must be established before investigators commit to this "gold standard" as the basis for their research. The purpose of this study was to develop a quality assurance (QA) model as an integral component of the "truth" collection process concerning the location and spatial extent of lung nodules observed on computed tomography (CT) scans to be included in the Lung Image Database Consortium (LIDC) public database. MATERIALS AND METHODS: One hundred CT scans were interpreted by four radiologists through a two-phase process. For the first of these reads (the "blinded read phase"), radiologists independently identified and annotated lesions, assigning each to one of three categories: "nodule >or=3 mm," "nodule <3 mm," or "non-nodule >or=3 mm." For the second read (the "unblinded read phase"), the same radiologists independently evaluated the same CT scans, but with all of the annotations from the previously performed blinded reads presented; each radiologist could add to, edit, or delete their own marks; change the lesion category of their own marks; or leave their marks unchanged. The post-unblinded read set of marks was grouped into discrete nodules and subjected to the QA process, which consisted of identification of potential errors introduced during the complete image annotation process and correction of those errors. Seven categories of potential error were defined; any nodule with a mark that satisfied the criterion for one of these categories was referred to the radiologist who assigned that mark for either correction or confirmation that the mark was intentional. RESULTS: A total of 105 QA issues were identified across 45 (45.0%) of the 100 CT scans. Radiologist review resulted in modifications to 101 (96.2%) of these potential errors. Twenty-one lesions erroneously marked as lung nodules after the unblinded reads had this designation removed through the QA process. CONCLUSIONS: The establishment of "truth" must incorporate a QA process to guarantee the integrity of the datasets that will provide the basis for the development, training, and testing of CAD systems.     

电离室矩阵用于加速器质量保证：X射线

目的：探讨利用二维电离室矩阵MatriXX进行医用直线加速器质量保证的方法及可靠性。方法：在点剂量的质量保证中。将MatriXX系统在特制水箱中测得的数据与O．6CC电离室在标准水箱中的剂量测量值作比较,从而定出Ma．triXX的校准系数．以此来校准射线的输出量和能量。在面剂量的质量保证中,用MatriXX测量医用加速器射线野的对称性、平坦度以及辐射野的大小及中心轴偏离．将测量结果与RFA300三维水箱扫描结果及控制台显示数值进行比较分析。结果：用MatriXX加有机玻璃板可准确快捷地完成对射线输出量和能量的校准。用MatriXX所测射野的对称性和平坦度及射线野大小与RFA300水箱的测量数据一致。结论：MatriXX系统进行加速器的质量保证简便可靠。     

Behavioral and histological analysis of a partial double-lesion model of parkinson-variant multiple system atrophy

Multiple system atrophy (MSA) is a neurodegenerative disease with progressive autonomic failure, cerebellar ataxia (MSA-C), and parkinsonism (MSA-P) resulting from neuronal loss in multiple brain areas associated with oligodendroglial cytoplasmic α-synuclein inclusion bodies. No effective treatments exists, and MSA-P patients often fail to respond to L-DOPA because of the loss of striatal dopaminergic receptors. Rendering MSA-P patients sensitive to L-DOPA administration following striatal tissue transplantation has been proposed as a possible novel therapeutic strategy to improve the clinical condition. Here we describes simple, skilled, and sensorimotor behavior deficits in a unilateral partial double-lesion (DL) rat model of MSA-P. The sequential striatal double-lesion model mimicks early MSA-P pathology by combining partial 6-hydroxydopamine (6-OHDA) followed by striatal quinolinic acid (QA) lesion. Animals were tested on spontaneous, learned, or drug-induced behavioral tasks on multiple occasions pre- and postsurgery. The data show robust, lateralized deficits, and the partial 6-OHDA and the double-lesioned animals were most impaired. Importantly, this study identified a behavioral deficit profile unique to the double-lesion animals and distinctive from the single 6-OHDA- or the QA-lesioned animals. Histology confirmed an approximately 40% dopamine loss in the striatum in the 6-OHDA and double-lesion animals as well as a similar loss of striatal projection neurons in the QA and double-lesion animals. In summary, we have established the behavioral deficit profile of a partial double-lesion rat model mimicking the early stage of MSA-P.     

锥形束CT在肿瘤放射治疗中的作用

目的探讨锥形束CT(cone beam,CT)在肿瘤放射治疗中的作用。方法对236例放疗患者,应用CBCT对摆位误差进行测量。对未在允许误差范围内的患者进行重新摆位,使其误差在允许范围内。将患者首次摆位误差记为Ⅰ组,重新摆位后的误差记为Ⅱ组,并对两组数据进行统计学分析。结果对数据比较分析发现,首次测量中有180例(76.3%)在允许误差范围内;48例(20.3%)未在允许误差范围内,需要重新摆位;8例(3.4%)出现不同原因的摆位错误。通过对未在允许误差范围内的48例患者进行重新摆位后,均使其误差控制在允许范围内,且重新摆位后各部位的摆位误差Ⅱ组均小于Ⅰ组。结论在肿瘤放疗中,应用CBCT对摆位误差进行测量,不仅能发现每位患者体位是否准确,且能及时发现治疗操作中的错误,而且为临床对PTV外放提供参考数据。     

Glutamate receptors and circuits in the vertebrate retina

We survey the evidence for L-glutamate's role as the primary excitatory neurotransmitter of vertebrate retinas. The physiological and molecular properties of glutamate receptors in the retina are reviewed in relation to what has been learned from studies of glutamate function in other brain areas and in expression systems. We have focused on (a) the evidence for the presence of L-glutamate in retinal neurons, (b) the processes by which glutamate is released, (c) the presence and function of ionotropic receptors for L-glutamate in retinal neurons, (d) the presence and function of metabotropic receptors for L-glutamate in retinal neurons, and (e) the variety and distribution of glutamate transporters in the vertebrate retina. Modulatory pathways which influence glutamate release and the behavior of its receptors are described. Emphasis has been placed on the cellular mechanisms of glutamate-mediated neurotransmission in relation to the encoding of visual information by retinal circuits.     

药品生产企业质量管理体系的合理设置

目的 建立药品生产企业质量管理体系的合理模式,完善药品生产企业的质量管理.方法 根据新版《药品生产质量管理规范》（GMP）对质量管理体系的要求,对企业药品质量管理体系的现状及实际操作中出现的问题进行分析比较.结果 当前,药品生产企业质量管理体系存在着信息沟通不畅,质量检验负责人（QC负责人）和质量监督负责人（QA负责人）素质参差不齐,验证工作不扎实,GMP培训不到位,供应商审核流于形式等诸多问题.结论 合理的药品生产质量管理模式,是有效发挥药品质量管理体系在药品生产中的作用,确保药品质量符合性和适用性的基石.