嗅神经母细胞瘤的CT和MRI表现

目的 探讨嗅神经母细胞瘤的CT和MRI影像特征,包括肿瘤部位、大小、累及范围、周围骨质破坏、密度及信号改变等.方法 回顾性分析我院2003～2009年13例经手术或穿刺病理确诊的嗅神经母细胞瘤的CT和MRI表现.结果 13例患者CT平扫示肿瘤密度不甚均匀,与软组织密度接近,内可见斑片状低密度.MRI显示:T1WI表现为低于脑灰质的低信号病灶,T2WI信号较脑组织稍高.13例中10例伴有囊变坏死,T1WI呈不均匀低信号,T2WI不均匀高信号,增强扫描明显不均匀强化.肿瘤同时累及颅内外者11例,双侧额叶同时受累1例,右侧额叶受累6例,左额叶受累4例,脑组织水肿7例.结论 嗅神经母细胞瘤的影像学表现无明显特异性,影像学检查可界定肿瘤累及范围及分期,对治疗方案的选择有重要价值.     

异位脑膜瘤的CT及MRI诊断

目的分析并探讨异位脑膜瘤的CT及MRI诊断价值。方法对我院2008年1月至2012年3月收治的16例异位脑膜瘤患者的影像学资料进行回顾性分析,分析并总结其CT及MRI表现特点。结果 16例异位脑膜瘤患者病灶多为类圆形,边界清晰,边缘较规则,少数患者病灶呈分叶状,边缘清晰,体积较大。MRI扫描结果显示,T1WI呈低信号或等信号,T2WI呈高信号、略高信号或等信号。增强扫描后,可见均匀强化或不均匀强化,肿瘤周围可见明显水肿与较粗大的血管影。异位脑膜瘤患者的病理类型为,纤维型9例(56.25%)、过渡型4例(25.0%)、砂粒体型2例(12.5%)、血管瘤型1例(6.25%)。结论 CT诊断异位脑膜瘤可以明确显示出钙化病灶,对肿瘤引起的骨改变可以直接显示,而MRI诊断异位脑膜瘤的优势为对软组织具有良好的分辨率,可从多方位对肿瘤进行观察,较好地显示了病灶与邻近组织的关系。CT与MRI扫描在诊断异位脑膜瘤中具有临床肯定意义。     

MRI对椎管内胚胎性肿瘤的诊断价值

目的评价MRI对41例椎管内胚胎性肿瘤的诊断价值。方法经手术证实的椎管内胚胎性肿瘤共31例,余10例经CT扫描证实,回顾性分析其MRI表现。结果脂肪瘤（13例）具有特征性MRI表现,T1WI呈高信号,T2WI呈中等高信号;通过脂肪抑制技术高信号变为低信号。皮样囊肿（3例）及表皮样囊肿（20例）,MRI表现为T1WI低或等低及T2WI高或等高混杂信号影,两者MRI不易鉴别。畸胎瘤（5例）,MRI可同时出现脂肪信号、骨质信号及软组织信号,亦可无骨质信号而表现为软组织和脂肪信号。结论椎管内胚胎性肿瘤诊断主要依据MRI表现,结合好发部位和年龄特征可进一步提高诊断正确率。     

多发胶质瘤MRI表现特点及鉴别诊断

目的：探讨多发胶质瘤磁共振成像(MRI)影像特点及鉴别。方法对7例经临床脑穿刺活检及手术病理确诊的多发胶质瘤患者MRI表现进行回顾性分析。结果7例患者中,5例为2个胶质瘤,1例为3个胶质瘤,1例为4个胶质瘤,主要分布于额叶、顶叶、颞叶区域。T1WI多呈稍低或低信号, T2WI呈不均匀高信号;瘤周均伴有不同程度水肿。增强扫描低级别胶质瘤为轻度不均匀强化,高级别胶质瘤多呈明显不均匀或花环样强化。结论多发胶质瘤中低级别胶质瘤表现具有一定特点,易于鉴别,而高级别胶质瘤术前诊断困难,易与颅内多发肿瘤或瘤样病变混淆,需注意鉴别。     

颅咽管瘤28例CT和MRI诊断分析

目的通过对颅咽管瘤的CT、MRI表现的分析,评价CT和MRI对颅咽管瘤的影像诊断价值。方法通过对28例经手术病理证实的颅咽管瘤的CT及MRI影像表现的分析,讨论该肿瘤的临床表现、影像诊断特征及鉴别诊断。结果 28例颅咽管瘤患者中,位于鞍内4例,鞍上17例,同时累及鞍内、鞍上7例;28例患者中,22例肿瘤呈囊性,CT表现为鞍区类圆形低密度灶,灶周伴蛋壳样钙化,MRI有24例表现为长T1WI长T_2WI信号,2例短T1WI长T2WI信号;5例呈囊实性表现,CT平扫为类圆形混杂密度灶,MRI在T1WI表现为低等混杂信号,T_2WI表现为高等混杂信号,增强扫描肿瘤实行部分呈均匀或不均匀强化,囊性部分呈环状强化;1例患者肿瘤为实性,CT表现为等密度或略高密度灶,MRI表现为等T_1WI长T_2WI,增强扫描肿瘤均匀或不均匀强化。结论 CT和MRI在颅咽管瘤的诊断中具有定性、定位及鉴别诊断价值。     

肾嫌色细胞癌的螺旋CT和MRI诊断价值

目的:探讨肾嫌色细胞癌的CT和MRI表现,提高其诊断符合率。方法:回顾性分析13例经手术和病理证实的肾嫌色细胞癌的CT和MRI影像资料。结果:CT检查13例,平扫呈软组织密度,大部分有分叶,肿瘤内部常见条状、小片状低密度影或星形低密度影,增强扫描皮髓期肿瘤强化低于肾皮质,而高于肾髓质。MRI检查4例,均见低信号包膜,CT平扫肿瘤内条状、小片状低密度影,T2WI脂肪抑制呈高信号,星形低密度影,T1WI为低信号,T2WI脂肪抑制为低信号。结论:肾嫌色细胞癌属少血供病变,CT强化表现配合MRI显示肿瘤内信号改变有助于肾嫌色细胞癌的临床诊断。     

颅内黑色素瘤的影像诊断(附7例分析)

目的探讨颅内黑色素瘤CT、MR影像特征及其诊断.材料和方法7例颅内黑色素瘤患者中男4例,女3例,年龄10-59岁.5例皮肤有黑色素瘤,2例有颅内黑色素瘤切除史.2例行CT加MRI,4例单行MR,1例仅行CT检查.结果3例CT平扫均为高密度影,形态不规则.增强扫描肿瘤明显增强.6例MRIT1WI肿瘤均表现为高信号,其中5例T2WI低信号,1例低高信号.T1WI增强扫描6例不规则增强.结论颅内黑色素性黑色素瘤MRI具有特征性表现,而非黑色素性黑色素瘤不具特征性,MRI显示黑色素瘤累及脑实质及浸润脑膜的范围和定性诊断优于CT.     

颅内原发淋巴瘤的CT和MRI表现

目的通过分析颅内原发淋巴瘤的影像表现,以提高诊断水平。方法回顾22例临床确诊的颅内原发淋巴瘤的影像资料,分析病灶的分布、形态、信号特点及强化特征。结果MRI显示14例为单发,8例为多发,主要病灶共40个,均位于幕上,其中位于大脑半球深部14个,灰白质交界区5个,累及胼胝体13个,基底节区及丘脑区8个。其中各有2例累及软脑膜及室管膜。病灶形态多为类圆形、团块或不规则状,边界较清晰,瘤周水肿及占位效应较轻。病灶T1WI呈等或略低信号,T2WI为等或略高信号。CT上病灶表现等密度或稍高密度22个,低密度18个。增强后所有病灶呈团块状或环状显著强化。结论颅内原发淋巴瘤CT、MRI表现及强化形式具有一定特征性,但仍须结合临床才能有效提高诊断准确率。     

毛细胞型星形细胞瘤的MRI诊断分析

目的探讨毛细胞型星形细胞瘤的MRI诊断价值。方法回顾性分析经手术病理证实的22例毛细胞型星形细胞瘤的MRI表现及治疗。结果 22例毛细胞型星形细胞瘤MRI上分三型：囊肿型8例（8/22）,囊肿伴结节型12例（12/22）,实体型2例（2/22）。18例（18/22）肿瘤全切,3例（3/22）肿瘤次全切,1例（1/22）大部切除。肿瘤囊性部分在T1WI呈低信号,T2WI呈高信号。肿瘤结节及实性部分T1WI呈等或稍低信号14例,T2WI呈高或稍高信号14例。增强扫描表现：肿瘤实性部分及结节,部分强化或完全强化。囊壁明显强化20例,轻度强化2例。肿瘤边界清楚,瘤周无水肿。结论毛细胞型星形细胞瘤属良性肿瘤,MRI表现有一定的特征性,结合临床资料有助于提高术前诊断的正确率,从而指导临床治疗。     

侧脑室脑膜瘤MRI诊断价值

目的 研究侧脑室内脑膜瘤的MRI表现特点,提高诊断的准确性.方法 回顾性分析6例经手术病理证实的侧脑室脑膜瘤MRI表现.结果 6例脑膜瘤呈类圆形或分叶状肿块,边界清楚.MRI多表现为T1WI等或稍低信号、T2WI等或稍高信号,信号较均匀,部分肿瘤内可见钙化(2/6)；周边脑组织可见不同程度的水肿.增强扫描大多数呈明显均匀强化；其中5例位于侧脑室三角区.结论 侧脑室脑膜瘤的MRI表现具有一定的特征性,结合临床资料可提高诊断的准确性.     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.