The x-ray sensitivity of amorphous selenium for mammography

A study of the x-ray sensitivity of amorphous selenium (a-Se) for digital mammography has been performed. A uniform layer of a-Se was deposited on a glass substrate with electrodes on both surfaces. The deposition procedure was identical to that used for a-Se flat-panel detectors. A high voltage was applied to the top surface of the a-Se layer in order to establish an electric field E(Se). Then the sample was exposed to x rays with 27 kVp spectra generated from an x-ray tube with a molybdenum (Mo) target. The mean x-ray energy of the spectrum used was approximately 16.6 keV. The x-ray current generated by the a-Se layer was measured as a function of E(Se). From the current measurement and the estimation of total x-ray energy absorbed in the a-Se, the energy required to create one electron-hole pair (EHP), W, was determined as a function of E(Se). It was found that at the most commonly used E(Se) of 10 V/microm, W was measured as 64 eV. This is considerably higher than the widely accepted typical value of W = 50 eV measured at higher x-ray photon energies (e.g., 50 keV). The dependence of W as a function of E(Se) can be best fitted using the empirical expression of E(Se)-gamma. This relationship is consistent with the results obtained at higher x-ray energies. This article provides an accurate measurement of x-ray sensitivity of a-Se at mammographic energies independent of detector operation, such as the most recently developed flat-panel detectors. The results will be a useful tool for investigation and optimization of a-Se-based x-ray imaging detectors, such as determination of pixel fill-factor and optimal E(Se) during operation.     

人缺血脑组织中IP-10和IFN-γ的表达

目的：探讨趋化因子IP-10和细胞因子IFN-γ是否参与人缺血脑损伤过程。方法：将21例脑梗死死亡病例按发病持续时间分为〈7天、7～14天和15～21天3组，以非缺血侧半球做对照，用HE染色法观察炎性细胞浸润情况；通过免疫组织化学方法检测缺血半球脑组织与非缺血半球脑组织中趋化因子IP-10和细胞因子IFN-γ的表达。结果：在〈7天组和7～14天组中，缺血脑组织可见大量炎性细胞浸润。在〈7天组、7～14天组和15～2l天组中，趋化因子IP-10在缺血半球脑组织中的表达高于非缺血半球（分别是1．74倍增高，P〈0．01；1．41倍增高，P〈0．05和1．52倍增高，P〈0．01）。在对细胞因子IFN-γ的检测中发现〈7天和7～14天组中，IFN-γ在缺血半球脑组织中的表达高于非缺血半球（分别是1．65倍增高，P〈0．05和1．32倍增高，P〈0．05）；在15～21天组中，IFN-γ在缺血半球与非缺血半球中的表达没有显著差异（P〉0．05）。结论：在人缺血脑组织中观察到IP-10和IFN-γ的表达，提示IP-10和IFN-γ参与了炎症反应对脑组织的损伤过程。同时也提示IP-10可能参与后期对损伤脑组织的修复。     

Intergeneration CAG expansion and contraction in a Chinese HD family.

The prevalence of juvenile-onset Huntington's disease (HD) is about ten times lower than adult HD. Here we report a Chinese HD family showing both intergeneration CAG expansion and contraction. The expansion resulted from a paternal transmission which leads to juvenile-onset HD for a 17-year-old Chinese boy (III-5). More interestingly, a contraction was noticed in a maternal transmission (III-3), which changed the CAG repeat from an expanded, disease-causing allele (48 repeats) to a normal or intermediate allele (34 repeats). Of note, the contraction resulted in a deletion of 14 CAG repeats, which is much larger than previously reported contractions. Our results are consistent with previous observations in Western Caucasians that juvenile-onset HD is more likely inherited through the male germline.     

Klebsiella pneumonia today]

Analysis of incidence and morphology of Klebsiella pneumonia nowadays in the adults (10 observations), children (5 observations) and newborns (23 observations) is presented. The pneumonias account for 11.3% of total number of lobar pneumonias in the adults dying in 1979-1989. Klebsiella infection represent 16.1% of total number of autopsies a year according to the pediatric infection pathology department. Etiological role of Klebsiella is established in 21.5% of total number of autopsies of newborns for 1985-1988, pneumonia being 61% of total Klebsiella infections. Klebsiella pneumonias in the adults correspond in principle to the Friedl?nder's pneumonia studied in detail by V.D. Zinserling (1891-1960) and his students. Generalized forms of, as a rule, hospital Klebsiellosis with most grave lung damage, unknown up to now, are frequently observed in children. Klebsiellosis was combined practically in all cases both in the adults and children with other bacterial, viral and fungal infections. The degree of clinico-morphological manifestations may considerably vary.     

Dimethyl sulfoxide elevates intracellular Ca2+ and mimics effects of increased light intensity in a photoreceptor

A 1% (v/v) solution of dimethyl sulfoxide (DMSO) added to the saline bath of isolated Balanus eburneus photoreceptors increased receptor potential amplitude by 40–50% and shortened time to peak amplitude and latency by 20–25%. The light-sensitive membrane current of voltage-clamped cells was increased systematically as DMSO concentration was increased from 1% to 10%. The null potential of the light sensitive current was unaffected by DMSO with short pulses of light, indicating that DMSO has no direct effect on ion selectivity of the light-sensitive channel. Absorbance changes of cell injected with the calcium indicator arsenazo III show that DMSO elevates intracellular Ca²⁺ (Ca_i). Current-voltage relations in darkness reveal that DMSO induces a small sustained inward current (5 nA) which has a null potential similar to the lightinduced current. DMSO may activate the light-sensitive conductance via the increase in Ca_i However, the altered kinetics and increased amplitude of the receptor current are opposite to the desensitizing effects normally observed with increased Ca_i.     

Fine-needle biopsy of the pancreas: Results of 204 routinely performed biopsies in 190 patients

Two-hundred and four fine-needle aspiration biopsies of the pancreas have been performed in 190 patients during a 12-year period. Sixty-one of these were performed percutaneously guided by endoscopic retrograde cholangio-pancreatography, percutaneous transhepatic cholangiography, angiography, or ultrasonography; and 143 were taken intraoperatively. In 77 (67%) out of 115 patients with pancreatic cancer, a correct cytological diagnosis was obtained. Two biopsies were reported as malignant in 1 patient who ultimately was found to have chronic pancreatitis (false positives). The frequency of not representative biopsies varied from 20.8% in patients with suspected cancer biopsied intraoperatively to 48.4% in patients biopsied preoperatively. A correct cytological diagnosis of malignancy was obtained preoperatively in 54.6% of patients with cancer, in 60.0% of patients evaluated without later operation, and in 71.1% of patients biopsied during laparotomy for suspected pancreatic cancer. The overall false-negative rate was 9.8%. The predictive value of a positive test was almost 100%, whereas the predictive value of a negative test was only 69.6% (total material). Analyses may indicate that a more aggressive approach with multiple punctures may lower the not representative biopsy rate and increase the diagnostic accuracy in patients with pancreatic cancer.

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Resumen Doscientas y cuatro biopsias pancreáticas por aspiración con aguja fina han sido realizadas en 190 pacientes en un período de 12 años. Sesenta y una de éstas fueron realizadas por vía percutánea guiada por colangiopancreatografía endoscópica retrógrada, colangiografía percutánea transhepática, angiografía, o ultrasonografía, y 143 fueron intraoperatorias. En 77 (67%) de 115 pacientes con cáncer del páncreas se obtuvo un diagnóstico citológico correcto. Dos biopsias fueron informadas como malignas en un paciente en quien finalmente se demostró pancreatitis crónica (falsas positivas). La frecuencia de biopsias no representativas varió entre 20.8% en pacientes con sospecha de cáncer y biopsia realizada intraoperatoriamente, a 48.4% en pacientes con biopsias realizadas en la fase preoperatoria. El diagnóstico citológico correcto de malignidad fue logrado preoperatoriamente en 54.6% de los pacientes con cáncer, en el 60.0% de los pacientes evaluados y sin operación posterior y en el 71.1% de los pacientes en quienes se realizó biopsia durante la laparotomía por sospecha de cáncer pancreático. La tasa global de resultados falsos negativos fue de 9.8%. El valor de predicción de una prueba positiva fue de casi 100%, mientras el valor de predicción de una prueba negativa fue de sólo 69.6% (material total). La implicación práctica de esto es que cuando se obtenga un resultado negativo se debe proceder con la toma de nuevas biopsias. En conclusión, creemos que la biopsia del páncreas con aguja fina es un procedimiento seguro que puede ser recomendado en todas las fases del proceso diagnóstico o terapéutico de lesiones pancreáticas, y que es valioso en la planeación de la terapia en pacientes con cáncer. Sinembargo, las biopsias negativas en casos de sospecha clínica de cáncer no siempre excluyen su presencia. Mayor análisis puede indicar que una actitud más agresiva, con punciones mÚltiples, puede disminuir la tasa de biopsias no representativas y aumentar la precisión diagnóstica en pacientes con cáncer pancreático.

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Résumé Deux cent quatre biopsies-aspirations à l'aiguille fine du pancréas ont été pratiquées chez 190 sujets au cours d'une période de 12 ans. Soixante et une d'entre elles ont été pratiquées par voie souscutanée en étant guidées par cathétérisme rétrograde, cholangiographie transpariétale, angiographie ou ultrasonographie et 143 ont été effectuées au cours de l'intervention. Chez 77 (67%) sujets appartenant à une série de 115 malades atteints de cancer du pancréas le diagnostic cytologique exact a été porté. Deux biopsies en faveur du diagnostic de cancer répondaient en réalité à des lésions de pancréatite chronique (faux positifs). La fréquence des biopsies ininterprétables chez les sujets suspects de cancer a varié de 20.8% lorsque l'examen a été pratiqué au cours de l'intervention à 48.4% lorsque ce mÊme examen a été effectué avant l'opération. Le taux de diagnostic cytologique exact de cancer a été respectivement de 54.6%, de 60.0% et 71.1% selon que la biopsie cytologique a l'aiguille a été pratiquée avant l'intervention, après un certain délai et au cours de l'opération. Au total, le taux des faux positifs s'est élevé à 9.8%. La fiabilité de la biopsie à l'aiguille a été proche de 100% en cas de biopsie positive mais seulement de 69.6% en cas de biopsie négative. L'analyse de l'ensemble de ces faits incite à adopter une attitude plus agressive c'est-à-dire à pratiquer des biopsies multiples au lieu d'une ponction unique pour réduire le taux des prélèvements ininterprétables et accroÎtre celui des résultats exacts.

     

氧化应激在溃疡性结肠炎中的作用及中医药防治研究进展

溃疡性结肠炎（UC）是一种临床常见的消化系统疾病,致病机制尚不明确,病情复杂多变,迁延难愈,治疗周期漫长,且无特效药。目前,UC的治疗多采用皮质类固醇、氨基水杨酸及生物制剂等西医手段,短时间起效快,疗效确切。但随着用药时间的延长,部分患者会出现耐药性和加剧病情发展,导致结肠癌的发生。有研究发现,氧化应激是UC重要的致病因素之一,影响着UC的发生、发展。氧化应激是机体内氧化产物与抗氧化系统不平衡的一种应激状态,丙二醛（MDA）、活性氧（ROS）、一氧化氮（NO）等氧化产物的过表达或者超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽（GSH）抗氧化酶的不足都会导致氧化应激的发生。值得注意的是,中医药作为我国独有的医学特色,运用中医药治疗UC疾病已经取得显著的成效。研究表明,中医药一方面通过抑制代谢产物的堆积,有效抑制UC发生,另一方面,通过提高抗氧化系统,达到拮抗UC发展的治疗效果。因此,以中医药调节氧化平衡状态作为诊疗思路,可能是未来治疗UC疾病的新手段、新方向。基于上述研究,该文总结了氧化应激关键致病蛋白与UC发生、发展的作用机制,归纳了中药有效成分、单味中药、中药复方、针灸调控氧化应激上下游靶点蛋白,减轻肠黏膜病理损害,降低结肠损伤指数,以及丰富肠道菌群,增加结肠长度,改善UC临床症状,以期为扩大中医药治疗UC疾病的应用范围,提供可靠的科学理论依据。     

Postnatal Iron Supplementation with Ferrous Sulfate vs. Ferrous Bis-Glycinate Chelate: Effects on Iron Metabolism,Growth, and Central Nervous System Development in Sprague Dawley Rat Pups

Iron-fortified formulas and iron drops (both usually ferrous sulfate, FS) prevent early life iron deficiency, but may delay growth and adversely affect neurodevelopment by providing excess iron. We used a rat pup model to investigate iron status, growth, and development outcomes following daily iron supplementation (10 mg iron/kg body weight, representative of iron-fortified formula levels) with FS or an alternative, bioavailable form of iron, ferrous bis-glycinate chelate (FC). On postnatal day (PD) 2, sex-matched rat litters (n = 3 litters, 10 pups each) were randomly assigned to receive FS, FC, or vehicle control until PD 14. On PD 15, we evaluated systemic iron regulation and CNS mineral interactions and we interrogated iron loading outcomes in the hippocampus, in search of mechanisms by which iron may influence neurodevelopment. Body iron stores were elevated substantially in iron-supplemented pups. All pups gained weight normally, but brain size on PD 15 was dependent on iron source. This may have been associated with reduced hippocampal oxidative stress but was not associated with CNS mineral interactions, iron regulation, or myelination, as these were unchanged with iron supplementation. Additional studies are warranted to investigate iron form effects on neurodevelopment so that iron recommendations can be optimized for all infants.     

中风发病后6—9月的生命质量

目的 比较发病后6－9月的中风患者与正常对照的健康差异,以明确针对中风患者的社区卫生服务应着手解决的健康问题。方法 对150例中风后6－9月的患者及按照性别、年龄、居住环境进行1：1配对的正常对照,采用SF－36进行健康自评,比较不同领域的健康状况。结果 患者生命质量在躯体功能、生理性角色功能受限、 社会功能、活力4个领域（P＜0．01）随年龄的增加而降低。男性生命质量在总体健康（P＝0．017）、躯体功能（P＝0．015）、活力和精神健康（P＜0．01）等4个领域好于女性。患者与对照比较,除了疼痛（P＝0．289）领域外,患者生命质量的各个领域均差于对照（P≤0．001）。结论 患者以发病后6－9月时,除了存在严重的躯体功能障碍之外,还有严重的心理、社会功能障碍以及角色功能障碍。其中,精神健康和女性患者是工作重点。