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排序方式: 共有1266条查询结果,搜索用时 31 毫秒
981.
FA Eggink GR Melles FJ Rietveld WH Beekhuis PS Binder 《Canadian Metallurgical Quarterly》1999,15(1):74-75
The excurrent duct system of the rat submandibular gland consists of a number of distinct segments. Using the direction of salivary flow as a reference point, these segments are, in order, intercalated duct, granular convoluted tubule, striated duct, excretory duct, main excretory duct (MED), and salivary bladder (which is an expanded portion of the MED). Because these ducts (with the exception of the MED and the salivary bladder) are encased in secretory endpieces, they are difficult to locate and to observe by scanning electron microscopy. A simple method has been devised to rid the gland of these obscuring endpieces so that the detailed architecture of the duct system can be examined. Rat submandibular glands were fixed initially by vascular perfusion with half-strength Karnovsky's fixative. The connective tissue capsule was removed from extirpated glands and the glands remained in fixative for varying lengths of time. For our purposes, a 30-minute immersion in the aldehyde mixture was optimum. After the sublingual gland was removed, the submandibular gland was softly struck with forceps having rounded tips, then shaken in fixative or buffer. The tissue that remained was postfixed in osmium tetroxide. This method results in the complete divestment of nonductular parenchyma from the rat submandibular gland, leaving the duct system clean and ready for microscopic examination. 相似文献
982.
Current methods for direct gene transfer into hematopoietic cells are inefficient. Here we show that functional complementation of Fanconi anemia (FA) group C cells by protein replacement can be as efficacious as by transfection with wild-type FAC cDNA. We expressed a chimeric protein (called His-ILFAC) consisting of the mature coding portion of gibbon interleukin-3 (IL-3) and full-length FAC in Escherichia coli. The purified bacterial protein is internalized by hematopoietic cells via IL-3 receptors. The intracellular half-life of His-ILFAC is approximately 60 minutes, which is comparable to that of the transgene-encoded FAC protein. In this cell-culture model His-ILFAC completely corrects the sensitivity of FA group C cells to mitomycin C, but it has no effect on FA cells that belong to complementation groups A and B. We suggest that receptor-mediated endocytosis of cytokine-fusion proteins may be of general use to deliver macromolecules into hematopoietic progenitor cells. 相似文献
983.
Cystic renal cell carcinoma is cured by resection: a study of 24 cases with long-term followup 总被引:2,自引:0,他引:2
FA Corica KA Iczkowski L Cheng H Zincke ML Blute A Wendel TJ Sebo R Neumann DG Bostwick 《Canadian Metallurgical Quarterly》1999,161(2):408-411
PURPOSE: The true incidence and biological behavior of cystic renal cell carcinoma are not known. To our knowledge we present the largest series of patients with cystic renal cell carcinoma with long-term followup. MATERIALS AND METHODS: We reviewed the Mayo Clinic surgical pathology files of renal cell cancer cases with a cystic component resected from 1969 to 1997, and arbitrarily chose 75% tumor involvement by cysts as a cutoff for inclusion in the study. RESULTS: We identified 24 cases of clear cell renal cell carcinoma with 75% or greater involvement by cysts comprising 0.79% of 3,047 renal cell cancer cases resected at our institution between 1969 and 1997. Mean patient age was 62.7 years (range 40 to 83). A total of 11 patients (46%) underwent radical nephrectomy, 4 (17%) simple nephrectomy, 3 (12%) partial nephrectomy and 6 (25%) tumor enucleation. Mean tumor involvement by cysts was 84% (range 75 to 95) and in 11 cases (46%) involvement was 90% or greater. Cancer stage was T1 in 20 patients (83%), T2 in 1 (4.4%) and T3a in 4 (12.5%). Cancers were diploid in all but 1 case. Mean followup was 77.6 months (range 8 to 428, median 51). A total of 22 patients (92%) had no evidence of cancer and 2 died of intercurrent disease. CONCLUSIONS: Our results indicate that cystic renal cell carcinoma is uncommon and usually cured by resection, regardless of size, stage or number of cysts. These patients may benefit from nephron sparing surgery, such as partial nephrectomy. 相似文献
984.
RW Jackson FA Treiber JR Turner H Davis WB Strong 《Canadian Metallurgical Quarterly》1999,31(2):111-119
In rat brain, expression of the gap junction protein connexin30 increased during the first 3 weeks after birth and reached its maximum after 4 weeks, as shown by analysis with specific connexin30 antibodies. This contrasts with the prenatal onset of connexin43 expression. On cryosections of rat brain, connexin30 immunoreactivity was found near blood vessels and in ependymal as well as in leptomeningeal cells. Expression in the neuropil was first noticed 3 weeks after birth, showing the same spatial pattern of immunoreactivity as connexin43. This late onset of connexin30 expression in astrocytes was also seen in long-term glial cell cultures, where connexin30 was coexpressed with the astrocytic marker proteins S-100beta and glial fibrillary acid protein. In acute brain slices, connexin30 immunofluorescent signals were detected on processes of functionally identified astrocytes. Thus, our results show that connexin30 is expressed in three different cell types of the rodent brain. The late onset of connexin30 expression in astrocytes suggests that this gap junctional protein fulfills a role in intercellular communication among mature astrocytes. 相似文献
985.
FA Lopez J Manglicmot TM Schmidt C Yeh HV Smith DA Relman 《Canadian Metallurgical Quarterly》1999,179(3):670-676
Cyclospora organisms are intestinal pathogens of humans that are increasingly recognized in many parts of the world; yet, the reservoirs and host range remain poorly defined. Analysis of 18S ribosomal DNA (rDNA) suggests that the human-associated Cyclospora species (Cyc-hu) is most closely related to the Eimeria species, which are host species-specific. Recently, oocysts identical to those of Cyc-hu were detected in baboon fecal specimens from Tanzania. The 18S rDNA from 3 of these baboon-associated oocyst specimens was amplified and sequenced. Phylogenetic analysis indicated that these baboon-associated Cyclospora-like organisms (Cyc-bab) are nearly identical to each other and are distinct from Cyc-hu (1.6%-1.7% dissimilar); however, these Cyc-bab organisms are the closest known relatives of Cyc-hu. Together, these primate-associated cyclosporans constitute a coherent clade within the diverse group of Eimeria species. These findings raise important questions about the evolutionary relationships of the eimeriids and Cyc-hu host range and should lead to improved polymerase chain reaction-based diagnostics. 相似文献
986.
模具激光表面熔覆设备和技术的进展 总被引:4,自引:0,他引:4
概述了激光表面熔覆技术近年来发展的概况;激光熔覆工艺,激光表面熔覆技术装备,以及熔覆材料概况。文中介绍了轧辊激光堆焊层厚10mm以上(单面)的新要求,以及激光熔覆层高硬度(HRC60-65)的新要求。 相似文献
987.
988.
989.
FA N Zhikang 《金属学报(英文版)》1995,8(3):190-194
CARBIDEFORMATIONINAUSTEMPEREDDUCTILEIRONALLOYEDWITHNICKELANDCOPPER¥FANZhikang(Xi'anUniversityofTechnology,China)SMALLMANRE(Un... 相似文献
990.
The high-cycle fatigue performance of different microstructures of aluminide coating-superalloy system has been studied at 900℃.The single phase coating of coarse equiaxialgrain NiAI(β)has unfavorable eJfect onJatigue life of the coating-superalloy.The fatigue lifemay shorten if the coating of NiAl(β)was an enrichment of coarse refractory metal grains.While an improvement can be made by dispersing numerous secondary phase particles such asextreme.fine γ′,quasi-σ-phase and others. 相似文献