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.     

7832例孕妇HCMV-IgM的检测分析

目的为了解孕妇人巨细胞病毒（HCMV）近期感染状况。方法采用酶联免疫吸附试验（ELISA）对7832例孕妇的静脉血标本进行了HCMV-IgM检测。结果在7832例孕妇中检测出HCMV-IgM阳性标本67例,阳性率为0.86%。结论在孕妇中巨细胞病毒有一定的近期感染率。     

磷酸组织胺诱导的Ⅰ型超敏反应对肝损伤作用的研究

目的:通过观察与Ⅰ型超敏反应相关的生物活性介质--组织胺对家兔肝脏有无直接损伤作用,进一步论证Ⅰ型超敏反应对肝脏的损伤作用.方法:选择34只家兔随机分为对照组、实验Ⅰ组和实验Ⅱ组3组;对照组只进行正常饲料喂养,实验Ⅰ组在正常饲料喂养的同时每天给予0.4μg/kg耳静脉注射磷酸组胺注射液,实验Ⅱ组在正常饲料喂养的同时每天给予0.08 μg/kg耳静脉注射磷酸组胺注射液;动态观察以上3个组的血清谷丙转氨酶(ALT)及血清谷草转氨酶(AST)变化;利用光学显微镜观察以上3个组肝组织的病理变化.结果:无论是实验Ⅰ组或实验Ⅱ组,经过一段时间的观察,发现血清内ALT和AST含量均显着高于对照组(P＜0.01),但Ⅰ、Ⅱ组之间无显着性差异(P＞0.05);实验Ⅰ组和实验Ⅱ组在显微镜下观察,其肝脏均有不同程的损伤和病理改变,且实验Ⅱ组的损伤和变化大于实验Ⅰ组,而对照组的肝脏则无明显的病理变化.结论:组织胺对家兔肝脏确实有一定的损伤作用,而且随着投予剂量和时间的增加,肝脏的损伤和病理变化也越显著;通过本研究,可以得出Ⅰ型超敏反应导致肝脏病理变化及损伤的见解.     

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.     

抗SARS-CoV抗原的人源Fab段噬菌体抗体库的构建

目的 :利用抗SARS冠状病毒IgG抗体阳性的SARS康复患者外周血淋巴细胞 ,构建人源Fab段抗体文库。方法 :制备外周血淋巴细胞总RNA ,逆转录成cDNA。以其为模板 ,利用针对家族特异性Ig基因的引物扩增重链Fd段和轻链基因 ,并重组到噬菌粒载体pComb3中 ,将重组噬菌粒载体电转化大肠杆菌XL 1Blue,酶切鉴定抗体库的重组率 ,并测定噬菌体抗体库的库容量。结果 :构建了源于SARS康复患者血清中抗Fab段的抗体文库 ,轻链、重链Fd段基因的重组率分别为91%和 75 % ,库容量为 7.2 3× 10 7。结论 :成功地构建了抗SARS CoV抗原的人源Fab段噬菌体抗体库     

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.