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排序方式: 共有2458条查询结果,搜索用时 15 毫秒
31.
A fraction of intrinsic membrane proteins was prepared from the major membranous cell components of rat liver by extraction of the membranes with KCl and deoxycholate. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the compositions of the intrinsic protein fractions from rough and endoplasmic reticulum, smooth endoplasmic reticulum. Golgi apparatus, plasma membrane, and nuclear envelope were similar to each other but distinct from that of mitochondria. Among endomembranes, differences were in the ratios of protein constituents plus a few protein bands of Golgi apparatus and plasma membranes not found in endoplasmic reticulum or nuclear envelope. The abilities of total rough endoplasmic reticulum, polysomes released from rough endoplasmic reticulum, and free polysomes to incorporate amino acids into the intrinsic protein fraction were tested in vitro. Polysomes bound to endoplasmic reticulum has the greatest capacity to synthesize proteins of this fraction as shown by co-purification of radioactive products and by immunoprecipitation. Although the majority of the radioactive products synthesized by bound polysomes were distinct from those synthesized by free polysomes, certain radioactive products synthesized by free polysomes also co-purified with intrinsic membrane proteins. The results show no absolute segregation between free and bound polysomes in the synthesis of intrinsic membrane proteins. However, the majority of these proteins appear to be synthesized by polysomes bound to the endoplasmic reticulum. Several intrinsic proteins found in plasma membranes do not appear in rough endoplasmic reticulum. To determine where these proteins were synthesized, the ability of other endomembrane components to support in vitro incorporation of [14C]leucine into protein was examined. In contrast to plasma membranes, isolated Golgi apparatus fractions did incorporate [14C]leucine to an extent greater than could be explained by contamination with rough endoplasmic reticulum. Golgi apparatus in situ and isolated from rat liver have polyribosomes associated with a zone of cytoplasm at the Golgi apparatus periphery occupied by tubules and vesicles. The polysomes are not directly attached to membranes as with rough endoplasmic reticulum and may represent a special class of "Golgi apparatus-associated" polysomes. The polysomes, when associated with Golgi apparatus membranes, incorporated amino acids in vitro. The products synthesized in vitro were analyzed by treatment with KCl and deoxycholate and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Certain proteins synthesized by the Golgi apparatus-associated polysomes remained insoluble after the treatment with KCl and deoxycholate. The proteins synthesized by the Golgi apparatus fraction had mobilities similar to proteins in plasma membranes which were absent from endoplasmic reticulum, and which were relatively minor components of Golgi apparatus... 相似文献
32.
Some new frictional parameters of fabrics determined by the trace analysis of their stick-slip friction property is reported. Both scouring and mercerization processes induce structural consolidation which in turn can increase the frictional resistance, number, amplitudes of the stick-slip, and the differential frictional forces of the fabrics. This result is ascribed to an increase in the crimp propensity of yarns. The magnitudes of the frictional parameters of weft pile fabrics are correlated with the numerical estimates of the tactile stimuli of their surface roughness. A good linear relation exists between the values of objective and subjective roughness of fabrics on a logarithmic scale. 相似文献
33.
WW Fisher LG Bowman RH Thompson SA Contrucci L Burd G Alon 《Canadian Metallurgical Quarterly》1998,31(3):493-496
Transcutaneous electrical nerve stimulation is used to reduce pain but also may be useful for self-injurious behavior (SIB). In the current investigation, a microcurrent electromedical device, classified as a transcutaneous electrical nerve stimulator (TENS), was applied with a man with Down syndrome who displayed SIB that persisted in the absence of social contingencies. Although clinically significant results were not maintained, a clear difference in the rates of SIB during active and inactive TENS was observed. 相似文献
34.
RH Bardales 《Canadian Metallurgical Quarterly》1998,18(3):373-99, v
This article covers the fine needle aspiration biopsy cytomorphology of papillary carcinomas of different organs, differential diagnoses, and clinical correlation. Diagnostic problems and helpful cytologic features are emphasized. The purpose is to have a concise source of information that helps the pathologist to evaluate these neoplasms. 相似文献
35.
NA Lokman AS Elder C Ricciardelli MK Oehler 《International journal of molecular sciences》2012,13(8):9959-9970
The majority of ovarian cancer patients present with advanced disease and despite aggressive treatment, prognosis remains poor. Significant improvement in ovarian cancer survival will require the development of more effective molecularly targeted therapeutics. Commonly, mouse models are used for the in vivo assessment of potential new therapeutic targets in ovarian cancer. However, animal models are costly and time consuming. Other models, such as the chick embryo chorioallantoic membrane (CAM) assay, are therefore an attractive alternative. CAM assays have been widely used to study angiogenesis and tumor invasion of colorectal, prostate and brain cancers. However, there have been limited studies that have used CAM assays to assess ovarian cancer invasion and metastasis. We have therefore developed a CAM assay protocol to monitor the metastatic properties of ovarian cancer cells (OVCAR-3, SKOV-3 and OV-90) and to study the effect of potential therapeutic molecules in vivo. The results from the CAM assay are consistent with cancer cell motility and invasion observed in in vitro assays. Our results demonstrate that the CAM assay is a robust and cost effective model to study ovarian cancer cell metastasis. It is therefore a very useful in vivo model for screening of potential novel therapeutics. 相似文献
36.
Margarita Garc��a-Hern��ndez Antonieta Garc��a-Murillo Felipe de J. Carrillo-Romo David Jaramillo-Vigueras Genevi��ve Chadeyron Elder De la Rosa Damien Boyer 《International journal of molecular sciences》2009,10(9):4088-4101
Transparent BaTiO3:Eu3+ films were prepared via a sol-gel method and dip-coating technique, using barium acetate, titanium butoxide, and polyvinylpyrrolidone (PVP) as modifier viscosity. BaTiO3:Eu3+ films ~500 nm thick, crystallized after thermal treatment at 700 ºC. The powders revealed spherical and rod shape morphology. The optical quality of films showed a predominant band at 615 nm under 250 nm excitation. A preliminary luminescent test provided the properties of the Eu3+ doped BaTiO3. 相似文献
37.
Garry Elder 《今日电子》2008,(1):33-35
人们对便携式产品更长运行时间的追求,促使燃料电池逐渐成为终端设备领域的新型电源。但是,在便携式应用中“只采用燃料电池”仍然面临诸多挑战。一种解决方法就是采用混合电源。 相似文献
38.
RH Ward GA Whyley DV Fairweather EI Allen T Chard 《Canadian Metallurgical Quarterly》1977,84(5):363-369
Serial estimations were made in plasma of 17beta-oestradiol (E2), progesterone and human placental lactogen (HPL) in 43 patients and of human chorionic gonadotrophin (HCG) in 34 patients during mid-trimester abortions induced with intra-amniotic prostaglandin F2alpha (PGF2alpha. Mean plasma concentrations of all the hormones showed a progressive fall after PGF2alpha. There was no relationship between the fall in levels of progesterone, HPL and HCG and the induction-abortion interval, signs of fetal distress or of intrauterine fetal death. Both the control level and the rate of fall of E2 were related to the induction-abortion interval and a rapid decline preceded intrauterine fetal death. The relationships of the progesterone/E2 ratio and the amniotic fluid volume/progesterone ratio to the induction-abortion interval were examined. The variation in the time at which significant falls in the concentration of individual hormones occurred was probably related to their respective half-lives in plasma. 相似文献
39.
Abnormalities in proliferation and protein synthesis in skin fibroblast cultures from patients with diabetes mellitus 总被引:1,自引:0,他引:1
Several aspects of in-vitro cell growth and protein synthesis were assessed in cultures of skin fibroblasts from subjects with juvenile-onset diabetes mellitus (JODM) or adult-onset diabetes mellitus (AODM) and from age-matched nondiabetic controls (C). There was an inverse correlation between increasing age and both the log-phase doubling rate and saturation density at confluence in C fibroblasts. JODM and AODM cells had a reduction in both indices of cell population growth in comparison with age-matched C fibroblasts. Fibroblasts grown in the presence of 0.3 micronM hydrocortisone were stimulated to grow more rapidly and to a greater saturation density. Stimulation of cell division by hydrocortisone accentuated the abnormalities in growth of JODM and AODM fibroblasts. Total protein and collagen synthesis was measured whtn the fibroblasts had grown to confluency in medium with or without hydrocorticone. Hydrocorticone did not produce a significant change in total protein and collagen synthesis per cell by C fibroblasts. Fibroblasts from AODM had a 180 per cent increase in total protein and collagen synthesis in the presence of hydrocortisone. In contrast, total protein and collagen synthesis decreased 40 per cent in fibroblasts from JODM when grown in the hydrocortisone medium. These studies indicate that skin fibroblast cultures from patients with diabetes exhibit abnormalities in cell proliferation. Furthermore, hydrocortisone appears to unmask diffeerences in protein synthesis that distinguish JODM and AODM fibroblasts in culture. 相似文献
40.
A new spectrophotometric method has been developed for determining diphenhydramine. HC1, based on solvent extraction into chloroform of the complex formed with bromocresol green. The complex solution in chloroform showed maximum absorption at 415 nm and obeyed Beer's law over the concentration range of 3.0-12.0 microgram/ml. The molar absorptivity of the complex was 2.02 x 10(4). Complex formation and extraction was complete and quantitative over the pH range from 2 to 5. The ratio of diphenhydramine to bromocresol green was 1:1. Excipients, coloring matter, flavoring agents, and other substances likely to be present in diphenhydramine preparations do not interfere in the determination. Direct determinations in tablet, capsule, sirup, and lotion preparations were carried out satisfactorily, and the average recovery was 100 +/- 1.0%. 相似文献