• 【在非常接近高压传输线的家庭中,短期住宅测量在预测72 h暴露于工频磁场中的准确性。】 复制标题 收藏 收藏
    DOI:10.1038/sj.jes.7500522 复制DOI
    作者列表:Ger WJ,Chang WP,Sung FC,Li CY
    BACKGROUND & AIMS: :Between February and April 2003, a total of 80 single-dwelling households close (< 70 m) to high-tension (161 or 345 kV) power lines in a northern community of Taiwan received measurements of indoor extremely low-frequency (ELF) magnetic field for 72 h. Measurements were performed with EMDEX II meter at a sampling rate of every 300 s, yielding some 860 readings of ELF magnetic field for each household. In addition to the 72-h mean ELF magnetic field, we also calculated arithmetic means of the first 2, 6, 12, and 288 readings taken in each household to represent the information on spot, 30-min, 60-min, and 24-h exposures, respectively. The mean 72-h exposure to ELF magnetic field for the 80 study households was estimated at 0.80 micro-Tesla (microT) with a standard deviation (SD) of 1.13 microT. The mean for pot, 30-min, 60-min, and 24-h exposure was 0.88 (SD 1.38), 0.90 (SD 1.40), 0.9 (SD 1.17), and 0.83 (SD 1.17) microT, respectively. There were high agreements, indicated by a nearly perfect intra-class correlation coefficient, between 72-h mean exposure and those short-term exposure measures. Additionally, the sensitivity and specificity of various short-term exposures in the prediction of 72-h exposure greater than 0.4 microT were similar at values of 0.82-0.87 and 0.93-0.95, respectively. This study indicates that short-term measurements of indoor ELF magnetic field seem adequate to represent the mean 72-h exposure, but tended to overpredict 72-h exposure greater than 0.4 microT. Further investigation is needed to assess whether these findings can be replicated in households far away from high-tension power lines.
    背景与目标: :在2003年2月至2003年4月之间,台湾北部一个社区中共有80个单户家庭靠近(<70 m)高压(161或345 kV)电力线,他们接受了室内极低频(ELF)的测量磁场72小时。使用EMDEX II仪表以每300 s的采样速率进行测量,每个家庭可获得约860个ELF磁场读数。除了平均72小时的ELF磁场外,我们还计算了每个家庭中头2、6、12和288个读数的算术平均值,以表示当场,30分钟,60分钟和24点的信息。 -h曝光。 80个研究家庭平均暴露在ELF磁场下72小时的时间为0.80微特斯拉(microT),标准偏差(SD)为1.13 microT。锅暴露30分钟,60分钟和24小时的平均值分别为microT的0.88(SD 1.38),0.90(SD 1.40),0.9(SD 1.17)和0.83(SD 1.17)。在72小时平均暴露量与那些短期暴露量之间,存在接近一致的类内相关系数,表明存在高度一致性。此外,预测72 h暴露大于0.4 microT时,各种短期暴露的敏感性和特异性分别为0.82-0.87和0.93-0.95。这项研究表明,室内ELF磁场的短期测量似乎足以代表72小时的平均暴露量,但往往会高估大于0.4 microT的72小时暴露量。需要进一步调查以评估这些发现是否可以在远离高压电线的家庭中复制。
  • 【胎儿小脑发育的磁共振成像。】 复制标题 收藏 收藏
    DOI:10.1080/14734220600589210 复制DOI
    作者列表:Triulzi F,Parazzini C,Righini A
    BACKGROUND & AIMS: :In the last few years fetal magnetic resonance imaging (MRI) has been proposed as a second level technique in the evaluation of fetal brain anomalies. It has been demonstrated that MRI is highly accurate in illustrating the morphologic changes of developing brain and fetal brain abnormalities being a useful procedure when ultrasonography is inconclusive or doubtful. Starting from the 19-20 weeks gestational age (GA), MRI can reliably depict fetal brain anatomy and locating pathology, offering a robust and reliable tool in the assessment of fetal CNS diseases. In this review both in vivo MRI quantitative and qualitative data about fetal cerebellar development are presented and compared with ultrasonography data. Fetal cerebellar development is gradual, steady, and largely comparable to the development of the supratentorial brain. Archicerebellar (flocculo-nodular lobe) and paleocerebellar (vermis) structures develop first, whereas neocerebellum (cerebellar hemispheres) develop slowly and largely after birth.
    背景与目标: :在最近几年中,胎儿磁共振成像(MRI)已被提出作为评估胎儿脑异常的第二级技术。已经证明,当超声检查不确定或值得怀疑时,MRI可以高度准确地说明发育中的大脑和胎儿脑部异常的形态变化,这是一种有用的方法。从19-20周胎龄(GA)开始,MRI可以可靠地描绘胎儿的大脑解剖结构和定位病理,从而为评估胎儿CNS疾病提供了强大而可靠的工具。在这篇综述中,提出了关于胎儿小脑发育的体内MRI定量和定性数据,并将其与超声检查数据进行了比较。胎儿小脑发育是渐进的,稳定的,并且在很大程度上可与上脑上脑的发育相媲美。先生小脑(结节状结节状)和小脑((状)结构,而新小脑(小脑半球)出生后缓慢且大部分发育。
  • 【骨髓嵌合体小鼠的肿瘤浸润基质细胞的制备和功能分析。】 复制标题 收藏 收藏
    DOI:10.1111/j.1348-0421.2006.tb03830.x 复制DOI
    作者列表:Ishigaki H,Yamamoto Y,Ishida H,Kajino K,Itoh Y,Fujiyama Y,Ogasawara K
    BACKGROUND & AIMS: :Tumor-infiltrating stroma cells (TISC) as well as tumors themselves are thought to be involved in tumor-related immunosuppression, which is one of the critical mechanisms of tumor escape from immune surveillance. However, preparation of TISC is difficult because of the small proportion of TISC in established tumors. Thus, the cells thought to be involved in tumor-related immunosuppression are generally prepared from spleens or draining lymph nodes in tumor-bearing mice. In this study, we developed a method for directly preparing TISC from established tumors in order to analyze their function. Using green fluorescent protein (GFP) transgenic (Tg) mice and C57BL/6 mice transplanted with bone marrow (BM) cells of GFPTg mice, we detected three subpopulations of TISC: one is compatible with immature myeloid cells (ImC) derived from BM and the two other subpopulations, CD11b(+) cells and CD11b(-) cells, do not originate from BM. The TISC including these subpopulations but not each subpopulation independently after culturing with tumors in the presence of GM-CSF could suppress T cell proliferation induced by anti-CD3. In our system, tumors did not inhibit T cell responses directly, but unknown factors from tumors affected immunosuppression by TISC.
    背景与目标: :肿瘤浸润基质细胞(TISC)以及肿瘤本身都被认为与肿瘤相关的免疫抑制有关,这是肿瘤逃避免疫监视的关键机制之一。然而,由于在已建立的肿瘤中TISC的比例很小,因此TISC的制备是困难的。因此,通常被认为与肿瘤相关的免疫抑制有关的细胞是从荷瘤小鼠的脾脏或引流淋巴结中制备的。在这项研究中,我们开发了一种从已建立的肿瘤中直接制备TISC的方法,以分析其功能。使用绿色荧光蛋白(GFP)转基因(Tg)小鼠和移植有GFPTg小鼠骨髓(BM)细胞的C57BL / 6小鼠,我们检测到TISC的三个亚群:一个与源自BM的未成熟髓样细胞(ImC)相容。其他两个亚群CD11b()细胞和CD11b(-)细胞并非源自BM。在存在GM-CSF的情况下与肿瘤培养后,TISC包括这些亚群,但并非每个亚群独立地抑制由抗CD3诱导的T细胞增殖。在我们的系统中,肿瘤并未直接抑制T细胞反应,但来自肿瘤的未知因素影响了TISC的免疫抑制。
  • 【丛枝菌根真菌分离株的功能多样性与根外菌丝网络有关。】 复制标题 收藏 收藏
    DOI:10.1111/j.1469-8137.2006.01839.x 复制DOI
    作者列表:Avio L,Pellegrino E,Bonari E,Giovannetti M
    BACKGROUND & AIMS: :We investigated the functional significance of extraradical mycorrhizal networks produced by geographically different isolates of the arbuscular mycorrhizal fungal (AMF) species Glomus mosseae and Glomus intraradices. A two-dimensional experimental system was used to visualize and quantify intact extraradical mycelium (ERM) spreading from Medicago sativa roots. Growth, phosphorus (P) and nitrogen (N) nutrition were assessed in M. sativa plants grown in microcosms. The AMF isolates were characterized by differences in extent and interconnectedness of ERM. Phenotypic fungal variables, such as total hyphal length, hyphal density, hyphal length per mm of total or colonized root length, were positively correlated with M. sativa growth response variables, such as total shoot biomass and plant P content. The utilization of an experimental system in which size, growth rate, viability and interconnectedness of ERM extending from mycorrhizal roots are easily quantified under realistic conditions allows the simultaneous evaluation of different isolates and provides data with a predictive value for selection of efficient AMF.
    背景与目标: :我们调查了丛枝菌根真菌(AMF)物种Glomus mosseae和Glomus intraradices的地理上不同的分离物产生的自由基外菌根网络的功能意义。二维实验系统用于可视化和量化从紫花苜蓿根部传播的完整的根外菌丝体(ERM)。在微观世界中评估了苜蓿植物的生长,磷(P)和氮(N)营养。 AMF分离株的特征是ERM的程度和相互连接性不同。表型真菌变量,例如总菌丝长度,菌丝密度,每毫米总或定殖根长度的菌丝长度,与苜蓿生长反应变量(如总枝生物量和植物P含量)呈正相关。在实际条件下容易量化从菌根根延伸的ERM的大小,生长速度,生存力和相互连接性的实验系统,可以同时评估不同的分离物,并为选择有效AMF提供具有预测价值的数据。
  • 【在流感血凝素的相同抗原位点具有特异性的辅助T细胞之间存在很大程度的功能多样性。】 复制标题 收藏 收藏
    DOI: 复制DOI
    作者列表:Haberman AM,Moller C,McCreedy D,Gerhard WU
    BACKGROUND & AIMS: :The site-1 determinant of the hemagglutinin molecule of influenza virus (A/PR/8/34) is one of several immunodominant sites in the BALB/c Th cell response to Ha. A synthetic peptide comprising this T cell site (HA110-120), a panel of analogs containing single substitutions in this determinant, and homologs truncated at the amino- or carboxyl-terminal were used to examine the fine specificities of 15 T cells specific for site-1 in the context of I-Ed. The results indicate that every residue within the minimal determinant plays a role in the T cell recognition process, as single substitutions at any of these positions affected the ability of the peptide to stimulate at least some site 1-specific T cells. For the majority of the residues examined, substitutions had dissimilar effects on distinct T cells, indicating that the substituted residues were affecting recognition in a receptor-specific manner. Each of the 15 T cells examined had a distinct fine specificity pattern, suggesting that the BALB/c T cell repertoire for this site is likely to exceed 100 distinct clonotypes.
    背景与目标: 流感病毒血凝素分子(A / PR / 8/34)的1位点决定簇是BALB / c Th细胞对Ha的免疫应答中的几个免疫优势位点之一。包含该T细胞位点的合成肽(HA110-120),在该决定簇中包含单个取代基的一组类似物以及在氨基或羧基端截短的同源物用于检查15个对该位点特异性的T细胞的精细特异性在I-Ed中为-1。结果表明,最小决定簇内的每个残基都在T细胞识别过程中起作用,因为这些位置中任何一个的单取代都会影响肽刺激至少一些位点1特异性T细胞的能力。对于所检查的大多数残基,取代对不同的T细胞的影响不同,表明取代的残基以受体特异性方式影响识别。检查的15个T细胞中的每一个都有独特的精细特异性模式,表明该位点的BALB / c T细胞库可能超过100种不同的克隆型。
  • 【黄色荧光蛋白变体YFP-H148Q / I152L的碘化钠转运蛋白活性的基于细胞的成像。】 复制标题 收藏 收藏
    DOI:10.1152/ajpcell.00291.2006 复制DOI
    作者列表:Rhoden KJ,Cianchetta S,Stivani V,Portulano C,Galietta LJ,Romeo G
    BACKGROUND & AIMS: :The sodium iodide symporter (NIS) mediates iodide (I(-)) transport in the thyroid gland and other tissues and is of increasing importance as a therapeutic target and nuclear imaging reporter. NIS activity in vitro is currently measured with radiotracers and electrophysiological techniques. We report on the development of a novel live cell imaging assay of NIS activity using the I(-)-sensitive and genetically encodable yellow fluorescent protein (YFP) variant YFP-H148Q/I152L. In FRTL-5 thyrocytes stably expressing YFP-H148Q/I152L, I(-) induced a rapid and reversible decrease in cellular fluorescence characterized by 1) high affinity for extracellular I(-) (35 muM), 2) inhibition by the NIS inhibitor perchlorate, 3) extracellular Na(+) dependence, and 4) TSH dependence, suggesting that fluorescence changes are due to I(-) influx via NIS. Individual cells within a population of FRTL-5 cells exhibited a 3.5-fold variation in the rate of NIS-mediated I(-) influx, illustrating the utility of YFP-H148Q/I152L to detect cell-to-cell difference in NIS activity. I(-) also caused a perchlorate-sensitive decrease in YFP-H148Q/I152L fluorescence in COS-7 cells expressing NIS but not in cells lacking NIS. These results demonstrate that YFP-H148Q/I152L is a sensitive biosensor of NIS-mediated I(-) uptake in thyroid cells and in nonthyroidal cells following gene transfer and suggest that fluorescence detection of cellular I(-) may be a useful tool by which to study the pathophysiology and pharmacology of NIS.
    背景与目标: :碘化钠共转运蛋白(NIS)介导碘化物(I(-))在甲状腺和其他组织中的运输,并作为治疗靶标和核成像报告者越来越重要。目前,使用放射性示踪剂和电生理技术测量了NIS的体外活性。我们报告了使用I(-)敏感和遗传可编码的黄色荧光蛋白(YFP)变体YFP-H148Q / I152L对NIS活性进行新型活细胞成像测定的发展报告。在稳定表达YFP-H148Q / I152L的FRTL-5甲状腺细胞中,I(-)诱导了细胞荧光的快速和可逆下降,其特征在于1)对细胞外I(-)(35 muM)的高度亲和力,2)NIS抑制剂的抑制作用高氯酸盐,3)细胞外Na()依赖性和4)TSH依赖性,表明荧光变化是由于I(-)通过NIS流入所致。 FRTL-5细胞群中的单个细胞在NIS介导的I(-)流入速率中表现出3.5倍的变化,说明了YFP-H148Q / I152L可用于检测NIS活性中的细胞间差异。 I(-)还在表达NIS的COS-7细胞中引起高氯酸盐敏感的YFP-H148Q / I152L荧光下降,但在缺乏NIS的细胞中不引起高氯酸盐敏感性下降。这些结果表明,YFP-H148Q / I152L是基因转移后甲状腺细胞和非甲状腺细胞中NIS介导的I(-)摄取的灵敏生物传感器,并表明细胞I(-)的荧光检测可能是一种有用的工具,研究NIS的病理生理学和药理学。
  • 【氟化分子在中枢神经系统中作为药物和显像剂。】 复制标题 收藏 收藏
    DOI:10.2174/156802606777951046 复制DOI
    作者列表:Sun S,Adejare A
    BACKGROUND & AIMS: :The strategic use of fluorine substitution in drug discovery and drug development is well documented. The small size and high electronegativity of fluorine are among properties of this element that lend special advantages. Applications in drugs targeted to the central nervous system (CNS) have been particularly fruitful in addition to favorable properties seen in many peripherally acting drugs. Fluorine substitution can be used to solve problems unique to the CNS, such as blood brain barrier (BBB) penetration. Likewise, use of the positron emitting isotope, (18)F, provides a unique tool for non-invasive imaging and diagnoses in the CNS. In this review, fluorine in CNS drugs and drug discovery are discussed.
    背景与目标: :氟取代在药物发现和药物开发中的战略用途已得到充分证明。氟的小尺寸和高电负性是该元素的特性之一,具有特殊的优势。除了在许多外围作用药物中看到的有利特性外,在针对中枢神经系统(CNS)的药物中的应用也特别富有成果。氟取代可用于解决CNS独有的问题,例如血脑屏障(BBB)渗透。同样,正电子发射同位素(18)F的使用为CNS中的非侵入性成像和诊断提供了独特的工具。在这篇综述中,讨论了中枢神经系统药物中的氟和药物发现。
  • 【膜联蛋白V磁激活细胞分选分离后的精子回收率评估。】 复制标题 收藏 收藏
    DOI:10.1016/s1472-6483(10)61437-x 复制DOI
    作者列表:Said TM,Agarwal A,Grunewald S,Rasch M,Glander HJ,Paasch U
    BACKGROUND & AIMS: :Magnetic-activated cell sorting (MACS) using paramagnetic annexin V-conjugated microbeads eliminates spermatozoa with externalized phosphatidylserine, which is considered one of the features of apoptosis. The objective of this study was to evaluate sperm recovery following the use of MACS as a sperm preparation technique. Mature spermatozoa were separated and divided into two fractions: the first was prepared by density gradient centrifugation (DGC) and MACS, while the second was prepared by DGC only. Following MACS, the percentage of cells collected in the annexin-negative fraction was significantly higher than the annexin-positive fraction and the sperm recovery rate was 73.8 +/- 12.1%. In conclusion, the integration of MACS with DGC can be considered as an effective sperm preparation technique that does not lead to significant cell loss. Separating a distinctive population of non-apoptotic spermatozoa with intact membranes may optimize the outcome of assisted reproduction.
    背景与目标: :使用顺磁性膜联蛋白V偶联的微珠进行磁激活细胞分选(MACS),消除了带有外部磷脂酰丝氨酸的精子,这被认为是细胞凋亡的特征之一。这项研究的目的是评估使用MACS作为精子制备技术后的精子回收率。将成熟的精子分离并分为两部分:第一部分通过密度梯度离心(DGC)和MACS制备,而第二部分仅通过DGC制备。进行MACS后,在膜联蛋白阴性组分中收集的细胞百分比显着高于膜联蛋白阳性组分,精子回收率为73.8 / 12.1%。总之,MACS与DGC的整合可以被认为是一种有效的精子制备技术,不会导致明显的细胞损失。用完整的膜分离非凋亡性精子的独特群体可以优化辅助生殖的结果。
  • 【螺旋CT血管造影术对腹部主动脉瘤进行完整的术前影像学评估。】 复制标题 收藏 收藏
    DOI:10.1016/s0009-9260(97)80132-8 复制DOI
    作者列表:Errington ML,Ferguson JM,Gillespie IN,Connell HM,Ruckley CV,Wright AR
    BACKGROUND & AIMS: PURPOSE:A prospective evaluation of spiral CT angiography (SCTA) as the sole pre-operative imaging modality for abdominal aortic aneurysm repair.

    MATERIALS AND METHODS:Spiral CT angiography was compared with conventional transfemoral angiography in 30 patients and results correlated with surgical findings in 22 patients. The following features were assessed: renal artery number and disease; upper and lower aneurysm extent; aneurysm size; perianeurysmal inflammation; iliac artery disease; radiation dose; and contrast usage.

    RESULTS:Spiral CT angiography agreed with conventional angiography in all cases of severe stenosis or occlusion of renal arteries and had 90% agreement overall for renal artery disease. Two of nine accessory renal arteries seen at conventional angiography were missed. For showing aneurysm extent SCTA was 100% sensitive, and performed better than conventional angiography. Aneurysm size was better shown with SCTA. In iliac disease SCTA, as performed in this study, was poor for mild-moderate disease, but detected four of six severely stenosed/occluded iliac arteries seen at conventional angiography. Prospective sensitivity for perianeurysmal inflammation was 33%. Radiation dose for SCTA was approximately twice and contrast dose approximately three times that for conventional angiography.

    CONCLUSION:Spiral CT angiography can provide all the necessary imaging information to plan aneurysm repair in the non-claudicant.

    背景与目标: 目的:前瞻性评价螺旋CT血管造影(SCTA)作为腹主动脉瘤修复术前唯一的影像学检查方法。

    材料与方法:螺旋CT血管造影与常规经股动脉血管造影在30例患者中进行了比较,结果与22例患者的手术结果相关。评估以下特征:肾动脉数量和疾病;上下动脉瘤程度;动脉瘤大小;动脉瘤周围炎;动脉疾病;辐射剂量

    结果:在所有严重狭窄或肾动脉阻塞的病例中,螺旋CT血管造影与常规血管造影相符,并且总体上90%符合肾动脉疾病。在常规血管造影术中发现的9条辅助肾动脉中有2条漏诊了。为了显示动脉瘤的程度,SCTA是100%敏感的,并且比常规的血管造影术表现更好。使用SCTA可以更好地显示动脉瘤的大小。在这项研究中进行的动脉疾病中,SCTA对于轻度中度疾病较差,但在常规血管造影术中发现了6条严重狭窄/闭塞的动脉中的4条。对动脉瘤周围炎症的预期敏感性为33%。 SCTA的放射剂量约为常规血管造影的两倍,对比剂量约为传统血管造影的三倍。

    结论:螺旋CT血管造影可以提供所有必要的影像学信息,以计划在非-claudicant。

  • 【神经放射学专业专家对脑CT成像研究进行重新解释的质量结果。】 复制标题 收藏 收藏
    DOI: 复制DOI
    作者列表:Jordan MJ,Lightfoote JB,Jordan JE
    BACKGROUND & AIMS: PURPOSE:To determine the clinical importance and relative value of reinterpreting brain CT imaging studies by subspecialty experts regarding changes in clinical management. METHODS:Computerized records were queried at two institutions during the years 2002-2003 for both primary interpretation by board-certified nonneuroradiologists and secondary interpretation by three neuroradiologists. A total of 1,081 cases were reviewed. Each case was initially interpreted as an emergent or urgent study. The reinterpreted studies were scored as concordant or discordant by the subspecialty experts. The discordant studies were then categorized as a "major discordance" if there was a change in clinical management, or as a "minor discordance" if there was no impact or change in clinical management. RESULTS:Of the 1,081 studies reviewed, 14 studies were identified as discordant (1.3%). Of those discordant studies, four were categorized as major discrepancies necessitating a change in clinical management (0.4 %). Ten were categorized as minor discrepancies (0.9%). There were no permanent adverse outcomes with respect to morbidity and mortality as a result of any discrepancy. CONCLUSION:The vast majority of interpreted head CT cases read by board-certified general radiologists do not result in discordant interpretations as verified by subspecialty experts. Discordant interpretations did not result in changes in clinical management in most cases. Double reading of head CTs by subspecialty experts appears to be an inefficient method of substantially improving imaging health quality outcomes.
    背景与目标: 目的:确定亚专业专家对临床管理变化进行重新解释脑CT成像研究的临床重要性和相对价值。
    方法:在2002年至2003年期间,在两家机构中查询了计算机记录,以获取由董事会认证的非神经放射科医生进行的主要解释和由三位神经放射科医生进行的次要解释。总共审查了1,081例。最初,每个案例都被解释为紧急研究。重新解释的研究被专业专家评定为一致或不一致。如果临床管理发生变化,则将不一致的研究分类为“重大不一致”,如果临床管理没有影响或发生变化,则将其分类为“轻微不一致”。
    结果:在所审查的1,081项研究中,有14项研究被确定为不一致(1.3%)。在这些不一致的研究中,有四项被归类为需要改变临床管理的主要差异(0.4%)。十个分类为轻微差异(0.9%)。任何差异都不会在发病率和死亡率方面带来永久性的不良后果。
    结论:经董事会认证的一般放射科医生阅读的绝大多数解释性头部CT病例,经专科专家验证,并不会导致不一致的解释。在大多数情况下,不一致的解释并不会导致临床管理的改变。专科专家对头颅CT进行双重读取似乎是一种实质上改善影像健康质量结果的无效方法。
  • 【功能性精子发生的发展需要生殖细胞凋亡的早期和大规模。】 复制标题 收藏 收藏
    DOI:10.1093/emboj/16.9.2262 复制DOI
    作者列表:Rodriguez I,Ody C,Araki K,Garcia I,Vassalli P
    BACKGROUND & AIMS: Transgenic mice expressing high levels of the BclxL or Bcl2 proteins in the male germinal cells show a highly abnormal adult spermatogenesis accompanied by sterility. This appears to result from the prevention of an early and massive wave of apoptosis in the testis, which occurs among germinal cells during the first round of spermatogenesis. In contrast, sporadic apoptosis among spermatogonia, which occurs in normal adult testis, is not prevented in adult transgenic mice. The physiological early apoptotic wave in the testis is coincident, in timing and localization, with a temporary high expression of the apoptosis-promoting protein Bax, which disappears at sexual maturity. The critical role played by the intracellular balance, probably hormonally controlled, of the BclxL and Bax proteins (Bcl2 is apparently not expressed in normal mouse testis) in this early apoptotic wave is shown by the occurrence of a comparable testicular syndrome in mice defective in the bax gene. The apoptotic wave appears necessary for normal mature spermatogenesis to develop, probably because it maintains a critical cell number ratio between some germinal cell stages and Sertoli cells, whose normal functions and differentiation involve an elaborate network of communication.

    背景与目标: 在雄性生殖细胞中表达高水平BclxL或Bcl2蛋白的转基因小鼠表现出高度异常的成年精子发生并伴有不育。这似乎是由于防止了睾丸早期大量凋亡的结果,这种情况发生在第一轮精子发生过程中的生发细胞之间。相反,在成年转基因小鼠中,不能阻止正常成年人睾丸中发生的精原细胞中的偶发性细胞凋亡。睾丸中的生理性早期凋亡波在时间和位置上是一致的,具有促凋亡的蛋白Bax的临时高表达,该蛋白在性成熟时消失。 BclxL和Bax蛋白的细胞内平衡(可能是激素控制的)(在正常小鼠的睾丸中显然不表达Bcl2)在细胞内平衡中起着至关重要的作用,这是通过在小鼠体内出现类似的睾丸综合症而证明的。 bax基因。凋亡波似乎是正常成熟精子发生发展所必需的,这可能是因为它在某些生细胞阶段和支持细胞之间维持了关键的细胞数比,其正常功能和分化牵涉到复杂的交流网络。

  • 【儿童实体器官移植后的脊柱:40例患者的临床,影像学和磁共振成像分析。】 复制标题 收藏 收藏
    DOI:10.1097/01.brs.0000231717.63974.f3 复制DOI
    作者列表:Helenius I,Remes V,Tervahartiala P,Salminen S,Sairanen H,Holmberg C,Palmu P,Helenius M,Peltonen J,Jalanko H
    BACKGROUND & AIMS: STUDY DESIGN:A cross-sectional study of the spine in 40 young adults after solid organ transplantation in childhood. OBJECTIVE:To evaluate the impact of organ transplantation and long-term immunosuppressive treatment on growing spine using magnetic resonance imaging (MRI). SUMMARY OF BACKGROUND DATA:A review of the current literature reveals no systematic evaluation of the spine after transplantation in childhood. METHODS:A total of 40 adult patients (mean age 22.1 years, range, 16.0-27.0), who received either kidney, liver, or heart transplant as children, were evaluated. Mean follow-up after transplantation was 11.2 years (range 3.0-18.0). All patients filled in a questionnaire, underwent an interview and physical examination, as well as had MRI of the spine. Standing spinal radiographs were taken from patients with a rib hump > or = 6 degrees. RESULTS:There were 8 (20%) patients who had a history of vertebral fracture. Eleven (28%) patients reported frequent back pain at rest. There were 15 (38%) patients who had scoliosis > 10 degrees (range 10 degrees -69 degrees ). On MRI, narrowed disc spaces were noted in 32 (80%) patients, and irregular endplates were noted in 24 (60%). There were 14 (35%) patients who had at least 1 compressed or wedged vertebra (> 20%). Patients treated for acute rejection had wedged vertebrae, speckled or black disc spaces, and irregular endplates more often than patients without rejections. Males had wedged vertebrae more often than females (P = 0.0067). CONCLUSIONS:Back pain, scoliosis, wedged vertebrae, and narrowed, degenerated disc spaces are common after solid organ transplantation in childhood.
    背景与目标: 研究设计:儿童实体器官移植后对40位年轻人的脊柱进行的横断面研究。
    目的:利用磁共振成像(MRI)评估器官移植和长期免疫抑制治疗对生长中脊柱的影响。
    背景资料摘要:对当前文献的回顾表明,儿童期移植后没有对脊柱进行系统评价。
    方法:总共评估了40名成年患者(平均年龄22.1岁,范围16.0-27.0),他们从小就接受了肾脏,肝脏或心脏移植手术。移植后的平均随访时间为11.2年(范围3.0-18.0)。所有患者均填写了问卷,接受了访谈和体格检查,并对脊柱进行了MRI检查。肋骨隆起>或= 6度的患者拍摄站立式脊柱X光片。
    结果:有8例(20%)有椎体骨折病史。 11名(28%)患者报告休息时经常出现背痛。脊柱侧弯> 10度(范围10度-69度)的患者为15(38%)。在MRI上,发现32例(80%)患者的椎间盘间隙变窄,发现24例(60%)的不规则端板。有14名(35%)患者至少有1块受压或楔入的椎骨(> 20%)。接受急性排斥反应的患者比没有排斥反应的患者更经常出现椎体楔形,斑点或黑色椎间盘间隙以及不规则的终板。男性比女性更经常楔住椎骨(P = 0.0067)。
    结论:儿童实体器官移植后,背部疼痛,脊柱侧弯,椎骨楔形和椎间盘狭窄变窄是常见的。
  • 【肌肉骨骼系统的磁共振成像。第8部分。脊柱,第1节。】 复制标题 收藏 收藏
    DOI:10.1097/00003086-199705000-00037 复制DOI
    作者列表:Gundry CR,Fritts HM
    BACKGROUND & AIMS: Magnetic resonance has assumed a preeminent role in the imaging evaluation of the spine. Owing to its multiplanar capability and superior soft tissue contrast, magnetic resonance imaging is the procedure of choice for a host of spinal disorders including degenerative disc disease, tumor evaluation, trauma, and spinal deformities. It represents the most accurate means of distinguishing between recurrent disc herniation and epidural fibrosis, and it excels at the assessment of many postoperative abnormalities such as infection, adjacent segment disc degeneration, and arachnoiditis. Magnetic resonance imaging is also helpful in the evaluation of numerous diagnostic challenges that are less well resolved by other means. This includes the distinction between disc herniation and epidural hematoma, synovial cyst from nonspecific fibrous thickening of a facet capsule, and the evaluation of numerous other soft tissue abnormalities. Computed tomography, computed tomography myelography, and scintigraphy continue to be useful for numerous specific disorders and in those patients with metal hardware or contraindications to magnetic resonance scanning. Overall, however, magnetic resonance is the imaging procedure preferred for many spinal disorders. This article is the first installment of a 3-part series discussing the role of magnetic resonance imaging of spinal disorders. Section 1 will describe the varying imaging modalities available and their relative advantages and disadvantages. A consideration of magnetic resonance imaging techniques will follow, followed by a discussion of the imaging manifestations of early degenerative disc disease. Section 2 will be devoted to an in depth discussion of specific pathologic processes encountered in patients with degenerative disc disease. Section 3 will end the series with a consideration of postoperative imaging followed by a discussion of spinal deformities, trauma, and neoplasms.

    背景与目标: 磁共振在脊柱的成像评估中发挥了重要作用。由于其多平面能力和出色的软组织对比度,磁共振成像是许多脊柱疾病(包括退行性椎间盘疾病,肿瘤评估,创伤和脊柱畸形)的首选程序。它代表了区分复发性椎间盘突出症和硬膜外纤维化的最准确方法,并且擅长评估许多术后异常,例如感染,邻近节段性椎间盘退变和蛛网膜炎。磁共振成像还有助于评估许多诊断挑战,而这些挑战很难通过其他方式解决。这包括区分椎间盘突出症和硬膜外血肿,小囊囊的非特异性纤维增厚引起的滑膜囊肿,以及许多其他软组织异常的评估。计算机体层摄影术,计算机体层摄影术脊髓造影和闪烁显像术继续对许多特定疾病以及那些具有金属硬件或磁共振扫描禁忌症的患者有用。但是,总的来说,磁共振是许多脊柱疾病首选的成像方法。本文是由三部分组成的系列文章的第一部分,该系列讨论了磁共振成像对脊柱疾病的作用。第1节将描述可用的各种成像方式及其相对优缺点。随后将考虑磁共振成像技术,然后讨论早期退行性椎间盘疾病的成像表现。第2节将专门讨论变性椎间盘疾病患者遇到的特定病理过程。第三部分将在结束本系列文章时考虑术后影像学,然后讨论脊柱畸形,创伤和肿瘤。

  • 【含细菌视紫红质的两相脂质双层中渗流的荧光猝灭和电子自旋共振研究。】 复制标题 收藏 收藏
    DOI:10.1016/S0006-3495(97)78909-4 复制DOI
    作者列表:Piknová B,Marsh D,Thompson TE
    BACKGROUND & AIMS: The effect of bacteriorhodopsin (BR) on the percolation properties of dimyristoylphosphatidylcholine/distearoylphosphatidylcholine bilayers was examined by studying the quenching of a lipid-bound fluorophore by a lipid-bound quencher, and by spin-spin interactions of a nitroxide-labeled lipid using electron spin resonance (ESR). At the low concentrations of BR used, differential scanning calorimetry showed that although the transition enthalpy was reduced in a concentration-dependent manner by incorporation of BR, the solidus and fluidus phase boundaries and overall shape of the heat capacity profiles were essentially unchanged. However, fluorescence quenching and spin-label ESR data showed that the domain topology, as reflected in the percolation properties, is strongly affected by the protein. In contrast to our previous fluorescence data for the pure lipid mixtures, quenching in the coexistence region is independent of the fluid phase fraction when BR is present. In addition, the percolation threshold estimated by spin-label ESR is shifted in the presence of BR to a higher gel phase fraction at a given lipid composition. Both the fluorescence quenching and spin-label ESR data, together with the results of earlier simulations, strongly suggest that the fluid phase domains are substantially larger and/or less ramified in the presence of BR than in its absence. We have previously reported a similar effect of a transmembrane peptide, pOmpA (Escherichia coli outer membrane protein A signal peptide), on fluid domain connectivity in binary phosphatidylcholine mixtures.

    背景与目标: 通过研究脂质结合的猝灭剂对脂质结合的荧光团的猝灭以及使用电子自旋的一氧化氮标记的脂质的自旋-自旋相互作用,研究了细菌视紫红质(BR)对二肉豆蔻酰基磷脂酰胆碱/二硬脂酰磷脂酰胆碱双层渗透特性的影响。共振(ESR)。在使用低浓度的BR时,差示扫描量热法显示,尽管通过掺入BR以一定的浓度依赖性降低了转变焓,但固相线和液相线的边界和热容曲线的总体形状基本不变。但是,荧光猝灭和自旋标记ESR数据表明,渗透特性所反映的域拓扑结构受到蛋白质的强烈影响。与我们以前的纯脂质混合物的荧光数据相反,当存在BR时,共存区域的猝灭与液相分数无关。另外,在给定脂质组成下,在BR存在下,自旋标记ESR估计的渗透阈值会转移到较高的凝胶相分数。荧光猝灭和自旋标记ESR数据以及早期模拟的结果都强烈表明,在存在BR的情况下,与不存在BR的情况相比,液相域的分支和/或分枝显着增加。我们以前曾报道过跨膜肽pOmpA(大肠杆菌外膜蛋白A信号肽)对二元磷脂酰胆碱混合物中的流体域连通性具有类似作用。

  • 【不同类型的刺激对兔颈总动脉中环AMP含量的影响:功能意义。】 复制标题 收藏 收藏
    DOI:10.1111/j.1471-4159.1990.tb03137.x 复制DOI
    作者列表:Pérez-García MT,Almaraz L,González C
    BACKGROUND & AIMS: :Cyclic AMP levels in rabbit carotid bodies incubated under control conditions, 100% O2- or 95% O2/5% CO2- equilibrated medium, are close to 1 pmol/mg wet tissue (range 0.4-2.43 pmol/mg). Isobutylmethylxanthine (0.5 mM) increases cyclic AMP levels by a factor of 14 and 8 in HEPES- and CO2/CH3O(-)-buffered medium, respectively. Forskolin (0.5-10 microM) applied during 30 min increases cyclic AMP levels in a dose-dependent manner. Incubation of carotid bodies at low O2 tensions resulted in an elevation of cyclic AMP levels both in the absence and in the presence of isobutymethylxanthine. In the latter conditions cyclic AMP increase was maximum at an O2 tension of 46 mm Hg and tended to decrease at extremely low PO2. In isobutylmethylxanthine-containing Ca2(+)-free medium, cyclic AMP increased linearly with decreasing PO2 from 66 to 13 mm Hg; the absolute cyclic AMP levels attained in Ca2(+)-free medium were smaller than those observed in Ca2(+)-containing medium at any PO2. The differences between Ca2(+)-free and Ca2(+)-containing media appear to be due to the action of released neurotransmitters in the latter conditions, because dopamine and norepinephrine, which are known to be released by hypoxia in a Ca2(+)-dependent manner, increase cyclic AMP in the carotid body. Low pH/high PCO2 and high [K+]e increase cyclic AMP levels only in Ca2(+)-containing medium. Forskolin potentiates the release of catecholamines induced by low PO2. These results suggest that cyclic AMP plays an important role in the modulation of the chemoreception process.
    背景与目标: :在对照条件下,100%O2-或95%O2 / 5%CO2平衡的培养基中孵育的兔颈动脉体中的循环AMP水平接近1 pmol / mg湿组织(0.4-2.43 pmol / mg范围)。在HEPES-和CO2 / CH3O(-)缓冲的培养基中,异丁基甲基黄嘌呤(0.5 mM)将循环AMP的水平分别提高14和8倍。在30分钟内施用的Forskolin(0.5-10 microM)以剂量依赖性方式增加循环AMP的水平。在不存在和存在异丁甲基黄嘌呤的情况下,在低O2张力下孵育颈动脉都会导致环AMP含量升高。在后一种情况下,循环AMP的增加在O2张力为46 mm Hg时最大,而在极低的PO2下趋于减少。在不含异丁基甲基黄嘌呤的不含Ca2()的介质中,环状AMP随着PO2从66 mmHg降低到13 mm Hg而线性增加。不含Ca2()的培养基中获得的绝对循环AMP水平要小于任何PO2含Ca2()的培养基中观察到的绝对值。不含Ca2()和含Ca2()的培养基之间的差异似乎是由于后者条件下释放的神经递质的作用所致,因为已知多巴胺和去甲肾上腺素在依赖Ca2()的低氧状态下会释放方式,增加颈动脉体中的循环AMP。低pH /高PCO2和高[K] e仅在含Ca2()的培养基中会增加循环AMP的水平。 Forskolin增强了低PO2诱导的儿茶酚胺释放。这些结果表明,环状AMP在化学感受过程的调节中起重要作用。

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