马氏碳球C60对体外培养Hela细胞的光敏杀伤效应

采用ＭＴＴ比色分析法,观察了不同Ｃ６０浓度和不同光照强度下Ｃ６０对体外培养的Ｈｅｌａ细胞的光敏杀伤效应。结果表明,Ｃ６０在３０ｕｇ／ｍｌ,光强４０００Ｌｕｘ的条件下即可杀伤大部分细胞。受伤细胞圆缩、脱壁,里面颗粒增多,失去表面微绒毛状结构。当光强增大时,细胞表面甚至出现破损。     

水溶性富勒烯C_(60)对肝细胞脂肪变性的改善效果研究

该文研究水溶性富勒烯C_(60)在体外对肝细胞脂肪变性的改善效果。首先利用游离脂肪酸诱导Huh6和WRL68细胞,建立肝细胞脂肪变的体外模型,再用水溶性富勒烯C_(60)干预脂肪变细胞,利用尼罗红染色法检测胞内的脂质蓄积程度,通过检测细胞内甘油三酯(TG)的含量、细胞活性氧(ROS)水平、超氧化物歧化酶(SOD)活力、还原性谷胱甘肽(GSH)和三磷酸腺苷(ATP)含量变化,比较C_(60)的作用效果。结果显示,游离脂肪酸诱导使得细胞蓄积脂滴明显增多,且TG和ROS水平显著升高,而C_(60)处理使得细胞脂肪蓄积减少,TG和ROS水平均下降,尤其是对氧化应激反应较为敏感的Huh6细胞,C_(60)的改善效果更佳。总之,C_(60)能有效改善肝细胞脂肪变性的程度,并缓解氧化应激所造成的细胞损伤。     

蓝藻Anabaena 7120光漂白细胞的吸氢

蓝藻光漂白细胞吸氢比其正常细胞小,对CO和O_2也很敏感。C_2H_2和分子氢预处理都导致蓝藻光漂白细胞吸氢下降。光下蓝藻光漂白细胞吸氢明显高于暗中,光强大的高于光强小的,暗中很微弱。此种吸氢也可为光合抑制剂所削弱或抑制。     

雷帕霉素对CAR-T细胞功能的影响

为探索雷帕霉素对CAR-T细胞体外杀伤靶细胞、杀伤后的扩增及细胞因子分泌能力的影响,该研究在体外使用靶向CD19的CAR-T细胞与CD19⁺CD22⁺Raji靶细胞的T细胞特异性杀伤模型,在不同效靶比、不同时相点、不同雷帕霉素浓度下,通过流式细胞绝对计数检测细胞杀伤率发现雷帕霉素不影响CAR-T细胞对靶细胞的杀伤能力。通过羟基荧光素二醋酸盐琥珀酰亚胺脂(CFSE)检测CAR-T细胞扩增能力,发现雷帕霉素通过抑制CAR-T细胞增殖而非促进凋亡的方式降低其活化后的扩增数量。通过流式细胞术微球阵列法(CBA)检测细胞因子分泌情况,发现雷帕霉素可显著性降低CAR-T细胞被靶细胞活化后的细胞因子分泌水平。综上所述,雷帕霉素可在不影响CAR-T细胞杀伤功能的前提下,降低其炎性因子分泌水平。     

肿瘤对自然杀伤细胞的杀伤敏感性研究

自然杀伤细胞（NK细胞）是机体抗肿瘤的第一道防线,是机体天然免疫的主要承担者,也是获得性细胞免疫的核心调节细胞。NK细胞对肿瘤的杀伤活性与其细胞表面受体和肿瘤细胞表面的配体密切相关,由于肿瘤细胞表面配体表达不同致使对NK细胞杀伤的敏感性有很大差异,临床疗效不一。我们简要介绍了影响肿瘤细胞对NK细胞杀伤敏感性的机制,对目前提高肿瘤细胞敏感性的策略和方法进行了总结。     

C_(60)对小鼠S_(180)肉瘤光动力学作用模型的建立

为验证C60 对活体肿瘤的光动力学损伤作用,我们从两方面进行实验 :C60 对荷瘤小鼠的S180实体瘤的光动力学杀伤作用和C60 对离体S180 肿瘤细胞的光动力学杀伤作用。在小鼠的瘤体上注射C60 光敏剂 ,在511nm和578nm混合黄绿色激光照射下 ,激发C60,产生大量的单线态氧 ,杀伤活性肿瘤。在激光光强为500mW ,C60 浓度为30μg/ml时 ,荷瘤小鼠寿命平均延长5天 ,瘤径减小1cm,瘤重减轻0.8克 ,在活体水平上验证了C60 的光动力学作用 ;另外,在离体的S180 肿瘤细胞中加入细胞培养物和C60 脂质体光敏剂 ,用碘钨灯照射激发C60。经MTT法和FDA -PI双色荧光分光光度法检测 ,离体S180 肿瘤细胞也明显被杀伤。C60 具有强的光敏剂作用 ,它不仅在活体水平上可以杀伤S180 实体瘤而且对离体的S180 实体瘤细胞有强的杀伤作用。     

培养条件下发菜的形态建成

固体培养基培养的发菜(Nostoc flagelliforme)在黑暗与低光强(2·s)条件下细胞发育受到抑制,在光强10、20、30、60 μmol/m2·s 条件下细胞生长良好, 但在60 μmol/m2·s 条件下藻丝体易变黄; 液体充气培养的发菜在光强20、60、180 μmol/m2·s 条件下生长速率、类胡萝卜素与多糖含量均随光强升高而增加。发菜在低营养水平时形成的异形胞较多, 异形胞的发生位置也多样, 有端生、间生和连生。当琼脂浓度为0.5%—4%时发菜具有相同的形态发育特征, 从藻殖段发育至丝状聚集体状态, 再从聚集体中释放藻丝; 当琼脂浓度为6%—8%时发菜发育至丝状聚集体状态, 藻丝包裹在厚胶鞘中, 观察不到藻丝和藻殖段的释放。以上结果表明光照和培养基的含水量对发菜细胞发育具有重要影响。       

富勒烯衍生物C60-叶酸对胃癌细胞生长抑制作用的研究

目的研究光照后的富勒烯衍生物C60-叶酸对体外培养的人类胃癌细胞杀伤及其促进胃癌细胞凋亡的作用。方法将光照后不同浓度C60-叶酸与人类胃癌细胞混合培养,用MTT方法检测不同条件下培养的人类胃癌细胞存活率。培养细胞免疫组化检测凋亡细胞中Caspase 3表达。Western blot比较各组中抗凋亡蛋白质Akt1的表达水平。结果随着光照后C60-叶酸浓度增加,人类胃癌细胞的存活率降低,同时凋亡细胞数量增多,且Akt1表达下调。结论 C60-叶酸光照后对人类胃癌细胞有较强的杀伤作用,作用机制与细胞凋亡有关。     

流感病毒利用其神经氨酸酶蛋白逃避NK细胞激活受体的识别

<正>自然杀伤(NK)细胞在抗病毒感染和消灭转化细胞的过程中发挥核心作用。通过抑制和激活受体控制病原体感染细胞和肿瘤细胞的识别。曾表明NK细胞激活(杀伤)受体中的天然细胞毒性受体NKp44和NKP46,可与流感病毒感染的细胞表面表达的病毒血凝素(HA)蛋白相互作用。我们进一步发现,NKp44/NKP46和病毒的HA之间的相互作用     

NKG2A的生物学特性与临床应用

NKG2A是主要表达于自然杀伤(natural killer, NK)细胞表面的抑制性受体,与NK细胞表面的激活性受体相互竞争,从而调控NK细胞的活性.近年来,抑制NKG2A免疫检查点可以恢复NK细胞活性从而杀伤肿瘤细胞,使得NKG2A成为抗肿瘤治疗的焦点之一.然而诸多研究发现,NKG2A还参与病毒感染、自身免疫等疾病...     

Stability to the extreme influences and significance of internal pH of Saccharomyces cerevisiae depending on the density of cellular suspensions

The resistance of a Saccharomyces cerevisiae population against gamma-irradiation (400 krd), heating (60 degrees C), repeated freezing--thawing and rehydration of dehydrated cells was shown to depend on the density of a cell suspension. The percentage of damaged cells (stained with primulin) was found to increase in a suspension with decreasing cell concentrations. The effect was also exerted in an oxygen-free medium. The percentage of undamaged cells increased in populations with a lower cell concentration when a more viscous medium (0.2% agar) was used. The intracellular pH dropped down in a denser intact yeast suspension and rose with an increase in the concentration of dehydrated-rehydrated cells.     

C_(60)对小鼠S_(180)肉瘤光动力学作用模型的建立

为验证Ｃ６０对活体肿瘤的光动力学损伤作用,我们从两方面进行实验：Ｃ６０对荷瘤小鼠的Ｓ１８０实体瘤的光动力学杀伤作用和Ｃ８０对离体Ｓ１８０肿瘤细胞的光动力学杀伤作用,在小鼠的瘤体上注射Ｃ８０光敏剂,在５１１ｎｍ、５７８ｎｍ混合黄录色激光照射正派主发Ｃ６０,产生大量的单线态氧,杀伤活性肿瘤。激光光强为５００ｍＷ,Ｃ６０浓度为３０μｇ／ｍｌ时,荷瘤小鼠寿命平均延长５天,瘤径减小１ｃｍ,瘤重减轻０．８克,     

Cadmium-induced hepatotoxicity in cultured rat hepatocytes as evaluated by morphometric analysis

Freshly isolated hepatocytes from neonatal rats were cultured for approximately 24 h; incubated for 5, 30, or 60 min in solutions containing 0, 50, 100, or 200 microM cadmium; embedded in plastic; and sectioned for optical microscopy. The extent of cadmium-induced hepatotoxicity was evaluated by double-blind morphometric analysis (a geometricostatistical processing of two-dimensional data for the collection of three-dimensional information) whereby hepatocytes were classified on the basis of the severity of morphologic damage at the optical level. Both time and concentration effects were studied. Cultures exposed to 200 microM cadmium, for various intervals of time from 5 to 60 min, showed statistically significant reductions in the relative volume percent of normal hepatocytes, elevations (then reductions) in the relative volume percent of slightly damaged hepatocytes, increases in the relative volume percent of moderately damaged cells, and increases in the relative volume percent of severely damaged liver cells. As the concentration of cadmium was increased from 50 to 200 microM cadmium (during both 30 and 60-min exposures), significant trends were observed in cellular distribution patterns based on relative volume percent. Morphologically normal cells decreased, both slightly damaged and moderately damaged cells increased, and severely damaged cells remained unchanged. These results indicated that morphometric analysis at the optical level provided quantitative estimates for the evaluation of time- and concentration-effects of cadmium on cultured hepatocytes.     

Cadmium-induced hepatotoxicity in cultured rat hepatocytes as evaluated by morphometric analysis

Summary Freshly isolated hepatocytes from neonatal rats were cultured for approximately 24 h; incubated for 5, 30, or 60 min in solutions containing 0, 50, 100, or 200 μM cadmium; embedded in plastic; and sectioned for optical microscopy. The exeent of cadmium-induced hepatotoxicity was evaluated by double-blind morphometric analysis (a geometricostatistical processing of two-dimensional data for the collection of threedimensional information) whereby hepatocytes were classified on the basis of the severity of morphologic damage at the optical level. Both time and concentration effects were studied. Cultures exposed to 200 μM cadmium, for various intervals of time from 5 to 60 min, showed statistically significant reductions in the relative volume percent of normal hepatocytes, elevations (then reductions) in the relative volume percent of slightly damaged hepatocytes, increases in the relative volume percent of moderately damaged cells, and increases in the relative volume percent of severely damaged liver cells. As the concentration of cadmium was increased from 50 to 200 μM cadmium (during both 30 and 60-min exposures), significant trends were observed in cellular distribution patterns based on relative volume percent. Morphologically normal cells decreased, both slightly damaged and moderately damaged cells increased, and severely damaged cells remained unchanged. These results indicated that morphometric analysis at the optical level provided quantitative estimates for the evaluation of time- and concentration-effects of cadmium on cultured hepatocytes. This work was supported by a grant from the Johns Hopkins University Center for Alternatives to Animal Testing.     

ENVIRONMENTAL FACTORS AFFECTING RESISTANCE TO DESICCATION IN THE DIATOM STAURONEIS ANCEPS

Several environmental parameters influence the ability of Stauroneis anceps Ehr. to survive periods of dehydration to equilibrium with atmospheric humidity. Cells grown in soil-water are better able to survive desiccation than cells grown in defined medium and cells from older cultures survive better than those from young cultures. Since active culture growth and cell division do not hinder survival, the factor responsible for increased survival in older cultures may be the accumulation of secreted metabolites in the medium. There is no survival when drying occurs in artificial substrata with particles 50 microns or less in diameter. Survival occurs when the particulate matter is 100 microns or larger. Slow drying seems to enhance survival, perhaps by allowing cells to interact longer with environmental organic substances conferring some degree of protection. Desiccated cells are better able to withstand temperature extremes than are vegetative cells in an aqueous environment. Dry cells survived longer than 9 days at 60 C and longer than 8 hr at 80 C but normal cultures were unable to survive 1 hr at 60 C. Temperatures of —15 to —20 C were also sustained more consistently by desiccated cells. Cells stored at vapor pressure deficits of 11.9 mm Hg or higher survived longer than 16 months but storage at 5.9 mm Hg or lower reduced survival time.     

Changes of phosphatidylserine distribution in human red blood cells during the process of loading sugars

The plasma membrane of red blood cells permits sugars to be loaded into the cytoplasm simply by incubation in a suitable buffer solution containing the sugar. This may provide some hope for the freeze-drying of human red blood cells. However, the effect of the loading process on red blood cells has not been fully investigated. The exposure of phosphatidylserine (PS) on the surface of the cell can be recognized by macrophages and result in shortened circulation in vivo. This study evaluates the effects of the concentration, the incubation time, and the temperature of exposure of human red blood cells to extracellular trehalose or glucose. Exposure of PS was demonstrated by annexin V labeling. It was shown that the efficiency of loading of glucose was significantly greater than that of trehalose. The loading efficiency of both sugars increased with increase in extracellular sugar concentration, prolongation of incubation time, and increase of incubation temperature. The percentages of cells with exposed PS and of damaged cells were dependent on the extracellular sugar concentration, the incubation time, and the temperature. With an extracellular glucose concentration of 0.8M, the percentage of cells with exposed PS was more than 80% and significantly higher than that of red blood cells loaded with trehalose (approximate 20%, P<0.01). As the incubation time was prolonged, the percentage of PS exposure and of damaged cells also increased. After incubation for 5h, the percentage of red cells with exposed PS following loading with glucose was more than 80% and significantly higher than that of cells loaded with trehalose (40%, P<0.01). In addition, the incubation temperature had a major effect on PS exposure. The percentage of cells with PS exposure and the proportion of damaged cells increased with increase of incubation temperature. At 37 degrees C, the percentage of cells with exposed PS and of damaged cells after loading with glucose was more than 80% and significantly higher than that of cells loaded with trehalose (P<0.01). However, when the temperature was below 25 degrees C, the percentage of cells with exposed PS and of damaged cells after loading with glucose or trehalose were both less than 10%. In conclusion, the loading efficiency for glucose was higher than that for trehalose, but the lesser effect of trehalose on exposure of PS suggests that it can maintain the asymmetrical distribution of membrane phospholipids and the intracellular trehalose can increase the osmotic tolerance of cells.     

Photoexcited calphostin C selectively destroys nuclear lamin B1 in neoplastic human and rat cells - a novel mechanism of action of a photodynamic tumor therapy agent

Lamin B1, a major component of the nuclear lamina, anchors the nucleus to the cytoskeletal cage, and controls nuclear orientation, chromosome positioning and, alongside several enzymes, fundamental nuclear functions. Exposing polyomavirus-transformed rat pyF111 fibroblasts and human cervical carcinoma (HCC) C4-I cells for 30 min to photoexcited perylenequinone calphostin C, i.e. Cal C(phiE), an established reactive oxygen species (ROS)-generator and protein kinase C (PKC) inhibitor, caused the cells to selectively oxidize and then totally destroy their nuclear lamin B1 by only 60 min after starting the treatment, i.e. when apoptotic caspases' activities had not yet increased. However, while the oxidized lamin B1 was being destroyed, lamins A/C, the lamin A-associated nuclear envelope protein emerin, and the nucleoplasmic protein cyclin E were neither oxidized nor destroyed. The oxidized lamin B was ubiquitinated and demolished in the proteasome probably by an enhanced peptidyl-glutaminase-like activity. Hence, the Cal C(phiE)-induced rapid and selective lamin B1 oxidation and proteasomal destruction ahead of the activation of apoptotic caspases was by itself a most severe molecular lesion impairing vital nuclear functions. Conversely, Cal C directly added to the cells kept in the dark damaged neither nuclear lamin B1 nor cell viability. Thus, our findings reveal a novel cell-damaging mechanism of a photodynamic tumor therapeutic agent.     

Apoptosis and cell desquamation in repair process of ischemic tubular necrosis

To elucidate the role of apoptosis and cell desquamation in the repair phase of acute tubular necrosis, morphological findings after 60 min ischaemia were investigated in rats. A morphometric analysis of the cell proliferation and of the epithelial cellularity of reconstructing tubules was performed. The kinetics of apoptosis and cell desquamation were also examined. Ischaemia and reperfusion injury resulted in widespread necrosis of tubules at day 1. Subsequently, a regenerative epithelial hyperplasia took place in the aarly stage. The most marked increase in cellularlity in the damaged tubules was on day 6, when the tubules became lined by hyperplastic epithelial cells with papillary clusters. The number of papillary clusters decrease up to day 8, and during this period many desquamated cells from the clusters were observed in the tubular lumen. In the later stage, hyperplastic epithelial cells were reduced to their original cellularity and during this period the number of apoptotic cells obviously increased, while the damaged tubules were reconstructed. We conclude that epithelial over-production occurs in the early phase after tubular necrosis, and excess hyperplastic epithelial cells regress during the repair process by cell desquamation and apoptosis, both of which are essential for the recovery of the original tubular structure.     

Effects of high temperature on the chlorophyll a fluorescence of Alhagi sparsifolia at the southern Taklamakan Desert

Climate change is expected to result in an increase in the frequency and magnitude of extreme weather events. Alhagi sparsifolia is an important factor for wind prevention and sand fixation in the forelands of the Taklamakan Desert. The effects of high temperature on desert plants remain widely unknown. In this work, chlorophyll a fluorescence induction kinetics were investigated at different time stresses of 5, 20, 40, and 60 min at temperature gradients of 38–44 °C at 2 °C intervals. A pronounced K-step was found, and the values of the maximum quantum yield for primary photochemistry, the quantum yield of electron transport, the density of reaction centers and the performance index on absorption basis were lowest after 60 min at 44 °C, thus indicating that the oxygen-evolving complex was damaged, the inactivated reaction centers increased, and the activity of the photosystem II (PSII) reaction center in leaves was seriously limited. Therefore, we suggest that under normal temperature (below 42 °C), the PSII of A. sparsifolia would be unaffected. When such temperature is maintained for 40 min, the activity of PSII would be limited, and when retained for 60 min, PSII may be severely damaged.     

High osmotic stress improves electro-transformation efficiency of fission yeast

A preincubation of fission yeast cells with hyperosmotic solution improved the electro-transformation efficiency. The efficiency increased approximately five-fold when the cells were preincubated with 2.0 M sorbitol and 1.5 M NaCl at 30 degrees C for 60 min before an applied high electric pulse. Losses in the efficiency of the cells after hyperosmotic stress above 2.5 M sorbitol and 2.0 M NaCl were directly related to the marked reduction of viability. The efficiency at 2.0 M sorbitol gradually increased until 60 min of the preincubation period, but longer exposure resulted in a gradual decrease. On the other hand, when the cells of the osmotic-sensitive mutant were preincubated with isosmotic solution of 0.5 M sorbitol, the efficiency was also dramatically increased by approximately 15-fold. These improvements in efficiency were observed in sublethal conditions of osmotic stress regardless of osmoticums and strains.