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1.
Dr. Patrick R. Cammarata Lawrence Oakford David Cantu-Crouch Robert Wordinger 《Cell and tissue research》1987,250(3):633-640
Summary The bovine lens capsule has previously been shown to provide an optimal surface for the examination of epithelial cell interaction with a basement membrane. This native substrate has been used to investigate some initial aspects of attachment of mouse blastocysts and trophoblastic cellular outgrowth. Mouse blastocysts were presented to the cell-free humoral side of the anterior lens capsule, incubated for 72 h, and examined by scanning and transmission electron microscopy. Blastocysts hatch and attach from their zonae pellucidae by 30 h. Trophoblastic cells proliferate rapidly in a coronal direction, display extensive surface microvilli, and advance by the extension of numerous filipodia, many of which terminate with bulbous projections. These projections were shown by transmission electron microscopy to contain numerous vacuoles and polysomes. To simulate further the initial blastocyst-uterine interaction, a suspension of lens epithelial cells was introduced to the capsule and permitted to form a monolayer prior to the addition of the blastocysts. At 72 h the monolayer of lens cells remained intact. We observed that: a) lens cells appear to recede from the advancing trophoblastic cells, and b) trophoblastic cells extend beneath the monolayer of lens cells and thereby dislodge the cells from the lens capsule substrate. No infiltration of the capsule by the advancing trophoblastic cells was observed. The lens capsule appears to offer a promising system for the study of trophoblast-epithelial cell interaction on a natural basement membrane. 相似文献
2.
Sven Skog Viola Eriksson Eva Eliasson 《Biochimica et Biophysica Acta (BBA)/General Subjects》1981,672(1):33-44
Suspension cultures of ‘Chang liver’ cells were synchronized by preincubation in a glutamine-deficient medium or by thymidine blockade. Specific arginase activity varied in the synchronized cultures, being high when the number of S-phase cells was maximal. A relationship between high arginase activity and a high percentage of (S+G2) cells was also found when unsynchronized cells were separated by velocity sedimentation. The increase in arginase activity near the G1/S border was totally inhibited in the presence of cycloheximide. The rate of decrease in activity after addition of the drug indicated that the variations in the rate of synthesis of the enzyme, while the rate of degradation was more or less constant, corresponding to 4–6% per h. The role of arginase in cells lacking a urea cycle and the regulation of arginase activity in ‘Chang liver’ cells is discussed. 相似文献
3.
G. Pellegrino D. Caimi M. E. Noce A. Musacchio 《Plant Systematics and Evolution》2005,251(2-4):119-129
The rewardless orchid Dactylorhiza sambucina shows a stable flower colour polymorphism, with both yellow- and red-flowered morphs growing sympatrically. Pollination biology and breeding system were investigated to examine the effects of density of plants, colour polymorphism, inflorescence dimension, and flower position within inflorescence on male and female reproductive success in three natural populations of D. sambucina. There were significant differences among sites in the number of pollinia removed and in fruit set per inflorescence. Number of removed pollinia and capsule production in D. sambucina were independent from flower and inflorescence size or flower position. As a whole, the red morphs showed the highest number of capsules produced, while the yellow morphs had the greatest male success. The relative male and female reproductive success were independent from plant density but were significantly correlated with the yellow morph frequency at the population level. Overall, our findings show that the contribution to the total reproductive success deriving from the two colour morphs does not conform with the predictions of negative frequency-dependent selection. 相似文献
4.
犬脑11只,经生理盐水冲洗脑血管后,注入20%钡胶液,切成0.2~1.0厘米的厚片,用显微X线法研究犬脑内各级动脉的构筑,其结果:1.皮质动脉的管径平均为25.9±0.005微米,平均长度为888.0±0.241微米。其形态与发出部位有关,分别呈栅状和瓶刷状。2.髓质动脉的管径平均为49.9±0.007微米。呈直线或孤形向心走行。3.皮质下动脉的管径平均为38.7±0.009微米。呈新月形或蟹钳状分布。4.豆纹动脉和内囊动脉的平均管径为70.0±0.021微米。呈锐角、反血流方向发自母干,再呈“S”形上升。5.丘脑动脉的平均管径为63.7±0.019微米,主要从下方进丘脑,呈树枝状分支。 相似文献
5.
Metallothioneins are a class of cysteine-rich and low molecular weight, metal-binding proteins that are inducible by a wide variety of agents, including metal ions, such as cadmium and zinc, glucocorticoid hormones, interferon, and tumor promoters. In an effort to delineate the regulation of the synthesis of the recently identified brain metallothionein-like protein, a study was undertaken to compare the induction of metallothionein in human neuroblastoma IMR-32 cells by zinc, cadmium, and dexamethasone using the human Chang liver cells as a control. Both cadmium (1 microM) and zinc (100 microM) significantly enhanced the incorporation of [35S]cysteine into metallothioneins isolated from both neuroblastoma and Chang liver cells. Dexamethasone in concentrations of 10 microM stimulated the synthesis of metallothionein in the Chang cells, whereas it had no effects on the synthesis of metallothionein in the neuroblastoma cells at concentrations ranging from 2.5--100 microM. The degree of stimulation of metallothionein synthesis in the Chang cells by cadmium and zinc was significantly higher than seen in neuroblastoma cells. The neuroblastoma IMR-32 exhibited less tolerance to the toxicity of both cadmium and zinc than the Chang cells, which may correlate with the inherent ability of these ions to induce metallothioneins in these dissimilar cells. The results of these studies are interpreted to indicate that the factors regulating the synthesis of metallothioneins in the Chang and neuroblastoma cells are not identical, suggesting also of the presence of dissimilar regulatory mechanisms in the liver and brain. 相似文献
6.
Cholecystokinin receptor mediated hydrolysis of inositol phospholipids in guinea pig gastric glands 总被引:1,自引:0,他引:1
CCK-octapeptide (CCK-8) (EC50 = 0.5 nM), in the presence of Li+, increased 3H-inositol phosphate (IP) accumulation in guinea pig gastric glands prelabeled with 3H-inositol. CCK-8 desulfate, human gastrin I and pentagastrin were much less potent than CCK-8. Antagonists of CCK receptors such as proglumide, dibutyryl-c-GMP and CBZ-Tyr (SO3H)-Met-Gly-Trp-Met-AspNH2 shifted the CCK dose response curve to the right. However, histamine (H1 and H2), cholinergic, substance P and alpha- and beta-adrenergic receptor antagonists had no effect on 3H-IP accumulation induced by CCK. The results suggest that CCK receptor activation in gastric glands leads to an enhanced breakdown of inositol phospholipids which may relate to calcium mobilization and pepsinogen secretion. 相似文献
7.
R. H. Berg 《Protoplasma》1990,159(1):35-43
Summary Enzyme-gold affinity labeling was used to show that in mature infected cells of actinorhizal symbioses the capsule on the plant host side of the symbiotic interface contained cellulose and xylans. Host species examined for cellulose wereAlnus rubra, Casuarina equisetifolia, C. glauca, Ceanothus cuneata, C. velutinus, Elaeagnus pungens, andMyrica cerifera.. Cellulose was in the capsule throughout the infected cell, implying that during development cellulose synthase was present in the host cell membrane component of the symbiotic interface. Any possible degradation of capsule cellulose by the microsymbiont was either incomplete or transient, because the polymer was present in mature infected cells. Cellulose labeling inCeanothus andElaeagnus was less consistent than in the other species. Dual labeled capsules inCasuarina glauca andAlnus rubra showed a similar distribution of xylans and cellulose. Cytochemical studies indicate that the capsule contains three major classes of cell wall polysaccharides: cellulose, hemicellulose (xylans), and pectins (shown previously). This suggests that the capsule is essentially a thin, internal, tubular plant cell wall.Abbreviations Au5
Au15 colloidal gold particles with mean diameter of 5 and 15 nm, respectively
- CBHI
cellobiohydrolase I
- CBHII
cellobiohydrolase II
- PBS
phosphate-buffered saline 相似文献
8.
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10.
摘要 目的:探讨枸橼酸托法替布片联合仙灵骨葆胶囊对类风湿性关节炎(RA)合并骨质疏松患者血清炎症细胞因子、骨强度及骨代谢水平影响。方法:纳入2021年8月至2022年8月期间徐州医科大学附属连云港医院诊治的80例RA合并骨质疏松患者。根据随机数字表法将患者分为对照组(雷公藤多苷片联合仙灵骨葆胶囊治疗)和实验组(枸橼酸托法替布片联合仙灵骨葆胶囊治疗),各为40例。对比两组疗效、炎症细胞因子、骨强度及骨代谢指标,观察两组不良反应发生率。结果:实验组的临床总有效率高于对照组(P<0.05)。实验组治疗后巨噬细胞集落刺激因子(M-CSF)、白细胞介素-1β(IL-1β)、环氧合酶-2(COX-2)低于对照组同期(P<0.05)。实验组治疗后横截面积(CSA)、横截面转动惯量(CSMI)、截面系数(Z)、皮质厚度(CT)高于对照组同期(P<0.05)。实验组治疗后骨钙素N端中分子(N-MID)、总Ⅰ型胶原氨基端延长肽(T-PINP)、骨钙素(BGP)、Ⅰ型胶原羧基端前肽(PICP)高于对照组同期,β-胶原降解产物(β-CTX)低于对照组同期(P<0.05)。两组治疗后腰椎骨密度和股骨颈骨密度较治疗前升高,且实验组高于对照组同期(P<0.05)。两组治疗后血沉(ESR)、C反应蛋白(CRP)、类风湿关节炎患者病情(DAS28)评分下降,且实验组低于对照组同期(P<0.05)。两组不良反应发生率组间对比无统计学差异(P>0.05)。结论:枸橼酸托法替布片联合仙灵骨葆胶囊应用于RA合并骨质疏松患者,可有效调节骨代谢水平,增强骨强度,降低血清炎症细胞因子水平。 相似文献