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排序方式: 共有3947条查询结果,搜索用时 15 毫秒
911.
OBJECTIVE: The purpose of this study was to evaluate the feasibility of administering topical contrast material during helical CT dacryocystography and topical saline solution during MR dacryocystography to reveal the lacrimal drainage apparatus. SUBJECTS AND METHODS: Fourteen healthy volunteers underwent helical CT dacryocystography, MR dacryocystography, or both. Eight of the 14 subjects underwent both techniques; three subjects underwent MR dacryocystography, and three subjects underwent CT dacryocystography. Images were evaluated by two radiologists for degree of visualization of components of the lacrimal drainage apparatus. Each volunteer was questioned about the relative discomfort of contrast material and saline solution administration. RESULTS: The lacrimal drainage system was seen on both CT dacryocystography and MR dacryocystography. CT dacryocystography allowed two-dimensional and three-dimensional reconstructions on which adjacent bone anatomy could be seen. The MR dacryocystography two-dimensional reconstructions and maximum intensity projections also showed the drainage apparatus. However, smaller drainage structures were more consistently seen on CT dacryocystography than on MR dacryocystography. Saline solution was more comfortable than contrast material. CONCLUSION: CT dacryocystography and MR dacryocystography reproducibly and non-invasively revealed the lacrimal drainage apparatus and allowed a better physiologic examination than cannulation dacryocystography. MR dacryocystography can be performed without administration of ionizing radiation or contrast material, but this technique cannot show adjacent bone anatomy and less consistently showed the smaller drainage structures than CT dacryocystography. 相似文献
912.
YF Lin HF Chen YS Yang HN Ho SM Chuang FJ Hsieh 《Canadian Metallurgical Quarterly》1994,93(11-12):954-957
Ovarian lipoid cell tumors are very rare. We report two cases with abnormal menstruation, hirsutism, clitoromegaly and marked elevations of serum testosterone. Sonography revealed unilateral adnexal solid tumors. Flow velocity wave form study showed apparent flow within the tumor with the resistance index ranging from 0.42 to 0.49 in both cases. Unilateral oophorectomy and contralateral ovarian biopsy were performed. Frozen sections showed lipoid cell tumors without malignant change. During surgery, direct ovarian venipuncture showed a discrepancy in testosterone level in the bilateral ovaries of both patients and large ovarian-peripheral venous gradients in case 2. The testosterone concentration returned to normal postoperatively in both cases. Flow velocity wave form study and direct ovarian venipuncture are useful tools for evaluation of androgen-secreting tumors preoperatively and intraoperatively. 相似文献
913.
914.
915.
The soluble methane monooxygenase (sMMO) enzyme complex of methanotrophs cometabolizes haloaliphatic compounds such as trichloroethylene. Two 18-mer oligonucleotides as primary primers and a nested primer of the same length were selected to amplify specific DNA sequences of the sMMO gene cluster using polymerase chain reaction (PCR). Two DNA fragments of sizes 270 and 400 base pairs were obtained when purified DNA from the methanotroph Methylosinus trichosporium OB3b was used as template. The primers were specific for sMMO sequences of M. trichosporium, since none of the 13 bacterial isolates screened yielded the expected length of PCR-amplified DNA fragments. The detection limit of the PCR method was 5 x 10(2) cells of M. trichosporium. The sMMO sequences were successfully amplified in groundwater (containing native microbial population) when seeded with M. trichosporium, FP1 sense (5'-ATGTCCAGCGCTCATAAC-3'), RP1 antisense (5'-TCAGATGTCGGTCAGGGC-3'), FP2 sense nested (5'GCCATCATCGGTCAGGGC-3'), and FP2 sense nested (5'-GCCATCATCGAGGACATC-3'). 相似文献
916.
917.
Dean S. T. Hsieh Nancy Smith Yie W. Chien 《Drug development and industrial pharmacy》1987,13(15):2651-2666
The in vitro and in vivo releases of estradiol from the recently marketed Compudose°-200 and -400 implants were evaluated. These subdermal implants are designed for subcutaneous controlled administration of estradiol in steers for 200- or 400-day growth promotion.
Analysis of the in vitro release profiles of estradiol from Compudose implants indicated that the release of estradiol is under a matrix diffusion-controlled process and follows a linear Q vs. t1/2 relationship.
The release flux from both Compudose-200 and -400 implants was found to be dependent upon the volume fraction of polyethylene glycol 400, which acts as the solubilizer for estradiol, in the aqueous elution solution.
Subcutaneous release of estradiol from Compudose implants was also conducted in laboratory rats for a duration of up to 114 days. Results indicated that the Q vs. t1/2 linearity is also followed. The subcutaneous rate of release was calculated to be 520 mcg/cm2/day1/2 for Compudose-200 and 360 mcg/cm2/day1/2 for Compudose-400. 相似文献
Analysis of the in vitro release profiles of estradiol from Compudose implants indicated that the release of estradiol is under a matrix diffusion-controlled process and follows a linear Q vs. t1/2 relationship.
The release flux from both Compudose-200 and -400 implants was found to be dependent upon the volume fraction of polyethylene glycol 400, which acts as the solubilizer for estradiol, in the aqueous elution solution.
Subcutaneous release of estradiol from Compudose implants was also conducted in laboratory rats for a duration of up to 114 days. Results indicated that the Q vs. t1/2 linearity is also followed. The subcutaneous rate of release was calculated to be 520 mcg/cm2/day1/2 for Compudose-200 and 360 mcg/cm2/day1/2 for Compudose-400. 相似文献
918.
KS Elenitoba-Johnson A Zarate-Osorno A Meneses L Krenacs DW Kingma M Raffeld ES Jaffe 《Canadian Metallurgical Quarterly》1998,11(8):754-761
Nasal T-lymphocyte/natural killer cell lymphomas (nT/NKLs) are a distinct group of neoplasms highly associated with Epstein-Barr virus (EBV), with a high prevalence in Asia but rare in Western countries. Recent studies indicate that these neoplasms are of cytotoxic T- or NK-cell derivation. Previous studies identifying a characteristic 30-base pair deletion within the 3' end of latent membrane protein-1 (del-LMP-1) in other EBV-associated lymphomas suggested a pathogenetic role for del-LMP-1 in those neoplasms. We examined 23 cases of nT/NKL from Mexico for expression of the cytolytic granular proteins TIA-1 and perforin (PRF), and for the presence of EBV by in situ hybridization (ISH). Polymerase chain reaction was performed to identify the EBV (EBNA-2) strain type and the status of the LMP-1 gene (del-LMP-1). Controls consisted of 11 sinonasal B-cell lymphomas (nBLs) and 30 reactive tonsils (RTs) from healthy Mexican individuals. The nT/NKLs expressed TIA-1 in 21 (91%) of 23 cases and PRF in 15 (65%) of 23 cases. In contrast, all of the nBLs were negative for TIA-1 and PRF. Twenty-two (96%) of 23 nT/NKLs were positive for EBV by ISH. In contrast, only 2 (18%) of 11 nBLs were positive for EBV by ISH. EBV strain Type A was identified in 21 (91%) of 23 cases, whereas strain Type B was present in 2 (9%) of the 23 nT/NKLs. A similar percentage (80%) of Type A was noted in 12 of the 15 RTs. del-LMP-1 was detected in 6 (26%) of 23 nT/NKLs, comprising 4 cases of Type A and 2 of Type B. del-LMP-1 was detected in 9 (45%) of 20 RTs. Our results indicated that TIA-1 and PRF were sensitive markers of nT/NKL. The presence of del-LMP-1 in comparable frequencies in the RTs and nT/NKLs suggested to us that this genotype was common in the Mexican population and argued against a definite pathogenetic role for del-LMP-1 in nT/NKL. 相似文献
919.
SL Primack KS Lee PM Logan RR Miller NL Müller 《Canadian Metallurgical Quarterly》1994,193(3):795-800
PURPOSE: To assess the utility of computed tomography (CT) in the evaluation of suspected bronchogenic carcinoma. MATERIALS AND METHODS: CT scans were reviewed of 362 patients who had undergone CT for suspected bronchogenic carcinoma. RESULTS: CT findings of 275 patients were consistent with bronchogenic carcinoma. Sixty-five tumors were deemed unresectable on the basis of CT findings, 21 were deemed unresectable on the basis of CT findings and poor surgical risk, 26 proved to be benign, six were metastatic disease from an extrathoracic primary tumor, and 157 were potentially resectable bronchogenic carcinoma. Surgical mediastinal nodal sampling enabled documentation of metastases in 60 of 159 patients. According to nodal station, the sensitivity of CT for metastases was 67% for nodes measured in the long axis and 58% for nodes measured in the short axis; specificity was 56% and 86%, respectively. CONCLUSION: CT can be used to confirm or exclude the presence of bronchogenic carcinoma and to obviate thoracotomy. The specificity of CT is limited, and a histologic diagnosis or follow-up evaluation is necessary. CT has limited value in staging mediastinal lymph nodes. 相似文献
920.
The band dispersion phenomena in capillary zone electrophoresis (CZE) using untreated and surface-treated open tubular and gel-filled capillaries were experimentally evaluated, with emphasis on small capillary diameters (10-100 microns). Laser-induced fluorescence detection was used for high-sensitivity detection of the isoindoles originated from model amino acids. The plots of plate height vs electric field strength were generated for different column radii and compared with a theoretical model for CZE. In addition to the diffusion-controlled band dispersion in the relatively low electric field range, adsorptive interactions between a solute and the capillary wall may play a certain role in band-broadening. The sorption-desorption kinetics become important with increasing electric field strength. Thermal effects appear to contribute little to band-broadening in relatively small capillaries (less than 50-microns i.d.) within normal operating voltages (less than 30 kV), but could become significant in capillaries with larger bores (greater than 75-microns i.d.). With gel-filled capillaries of small diameters (less than 50-microns i.d.), diffusion processes can be minimized. In addition, thermal effects do not appear critical in such columns at reasonable voltages. 相似文献