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1.
Suspensions of canine and human erythocytes hardened with acetaldehyde differ from the suspensions of normal erythrocytes with respect to their rheological behavior. Normal erythrocytes can be packed by centrifugation so that the sediment volume is nearly 100 percent cells, but the hardened erythrocytes (RBC's) can be packed only to approximately 60 percent cells. At the same cell percentage the viscosity of the hardened RBC suspension is higher than that of the suspension of normal erythocytes. An increase in shear stress deforms the normal erythocytes and lowers the suspension viscosity, but has no influence on the viscosity of the hardened cell suspension. In blood with high cell percentages, the shear deformation of normal RBC's plays an important role in reducing viscosity and facilitating flow at high shear stresses. 相似文献
2.
In the presence of Ringer's solution containing a high concentration of potassium ions, the incorporation of P(32)-orthophosphate into adenosine triphosphate and other organophosphates of the desheathed sciatic nerve of the bullfrog was inhibited by more than 75 percent. In calcium-free Ringer's solution containing ethylenediaminetetraacetic acid, the inhibition was about 30 percent. Both solutions depolarized the nerves, and the depolarization probably interfered with the mechanisms of phosphate transfer rather than directly with phosphorylation. The inhibition may have been a consequence of the decreased adsorption of phosphates which occurs at the excitable surface during depolarization. 相似文献
3.
Electronic separation of biological cells by volume 总被引：2，自引：0，他引：2
M J Fulwyler 《Science (New York, N.Y.)》1965,150(698):910-911
A device capable of separating biological cells (suspended in a conducting medium) according to volume has been developed. Cell volume is measured in a Coulter aperture, and the cells are subsequently isolated in droplets of the medium which are charged according to the sensed volume. The charged droplets then enter an electrostatic field and are deflected into a collection vessel. Mixtures of mouse and human erythrocytes and a large volume component of mouse lymphoma cells were separated successfully. In tests with Chinese hamster ovary cells essentially all cells survived separation and grew at their normal rate. 相似文献
4.
Chien S Usami S Dellenback RJ Gregersen MI Nanninga LB Guest MM 《Science (New York, N.Y.)》1967,157(3790):829-831
The addition of purified canine or bovine fibrinogen to suspensions of canine erythocytes in Ringer solution caused an increase in viscosity and the formation of aggregates of erythocytes. Both of these effects became increasingly pronounced as the fibrinogen concentration was raised, and they approached plateaus with 1 gram of fibrinogen per 100 milliliters. An increase in shear rate (or shear stress) reduced both the effect on viscosity and the aggregate size. The data suggest that fibrinogen causes an increase in blood viscosity and a departure from Newtonian behavior by interacting with erythrocytes to form cell aggregates which can be dispersed by shear stress. 相似文献
5.
Density gradient separation of marrow precursor cells restricted for antibody specificity 总被引：1，自引：0，他引：1
Potentially immunocompetent cells of (C57BL/6 x DBA/2) F(1) mouse bone marrow are committed to antigenic determinants of sheep or burro erythrocytes prior to interaction with thymus-derived cells and participation in immune responses to administered antigens. At this stage of differentiation marrow cells of this particular mouse strain are not yet restricted for the immunoglobulin M or immunoglobulin G antibody class. By equilibrium centrifugation in discontinuous gradients of bovine serum albumin, precursors of cells that produce antibody to sheep erythrocytes migrate to denser regions, whereas the precursors of immunocytes that produce antibody to burro erythrocytes remain in the lower density regions. cursors for all specificities. 相似文献
6.
Volumetric experiments on single fibers isolated from semiten-dinosus muscles of frogs, some performed in correlation with measurements of membrane potential, confirm the data obtained on whole muscles, but only for the specific range of conditions in which most of the latter experiments have been done. These conditions are restricted to media in which the anion ( Cl usually) is permanent and the K is 10 to 12.5 meqlliter, or four to five times above the normal level in Ringer's solution. When other ionic conditions are employed, phenomena are disclosed which have not previously been described. The findings throw doubt upon the validity of some generally accepted views regarding the permeability properties of the membrane of frog muscle fibers and regarding the nature of the mechanisms which regulate their volume. 相似文献
7.
Antibody formation in nonimmune mouse peritoneal cells after incubation in gum containing antigen 总被引：6，自引：0，他引：6
A E Bussard 《Science (New York, N.Y.)》1966,153(738):887-888
Peritoneal cells from normal mice in a semisolid medium containing sheep erythrocytes were incubated at 37 degrees C for 2 or 3 days. During this period, hemolytic antibodies developed spontaneously. Arguments are presented that true de novo synthesis of antibody has taken place in previously uncommitted cells. 相似文献
8.
Glucose-6-phosphate dehydrogenase in erythrocytes of the Negro type associated with enzyme deficiency (A(-)) was separated by chromatography on a carboxymethyl-Sephadex column from the electrophoretically indistinguishable Negro variant with normal enzyme activity (A(+)). Quantitative immunologic neutralization tests indicated that the A(-) enzyme had about the same enzymatic and serological activity as the A(+) and the normal (B(+)) enzymes. The enzyme activity of the A(-) variant in young erythrocytes was similar to that in young cells from normal individuals, although the activity of the A(-) variant in unfractionated red cells was 10 to 15 percent of normal. These data indicate that the basic defect in the variant enzyme (A(-)) is a structural mutation which causes more rapid degradation of the enzyme during erythrocyte aging. 相似文献
9.
Primitive cells of (C3H x C57BL/10)F(1) mouse bone marrow, participating with thymocytes in immune responses to sheep erythrocytes, are already committed to the immunoglobulin M or immunoglobulin G antibody class. By equilibrium centrifugation in discontinuous gradients of bovine serum albumin, cells responsible for production of IgM immunocytes migrate to the denser regions, whereas those responsible for IgG immunocytes remain in the lower density regions. 相似文献
10.
Force-area diagrams for monolayers of stearic acid on Ringer's solution demonstrate a competition between veratrine and calcium for carboxyl groups of the films. The competition occurs at customary concentrations. Local anesthetics act quite differently. The interactions suggest those observed less directly in living cells and therefore indicate that such surface films may serve as models for the study of drug and ion effects. 相似文献
11.
Protection against lethal hyperoxia by tracheal insufflation of erythrocytes: role of red cell glutathione 总被引：9，自引：0，他引：9
B S van Asbeck J Hoidal G M Vercellotti B A Schwartz C F Moldow H S Jacob 《Science (New York, N.Y.)》1985,227(4688):756-759
Intact erythrocytes placed into the tracheobronchial tree of hyperoxic rats dramatically improved their chances for survival. Over 70 percent of the animals so treated survived more than 12 days during continuous exposure to 95 percent oxygen, whereas all of the control animals died within 96 hours. Lungs from erythrocyte-protected rats showed almost none of the morphologic damage suffered by untreated animals. Erythrocytes containing cyanomethemoglobin were as beneficial as normal erythrocytes, but cells in which glutathione was partially blocked were significantly less protective. Analogous results were obtained in vitro: 51Cr-labeled target cells released 70 to 90 percent of their label when exposed briefly to hydrogen peroxide or to toxic oxygen species generated by phorbol ester-stimulated neutrophils. Addition of intact erythrocytes decreased release by approximately 75 percent, but significantly less than this if red blood cell glutathione was partially blocked. These results suggest that insufflated erythrocytes, through their recyclable glutathione, protect rats from toxic oxygen species engendered by hyperoxia. 相似文献
12.
13.
After hypertransfusion, normal ww and anemic WW(T) mice show the same increase in red-cell volume, decrease in reticulocytes, and temporary cessation of blood formation. The time required for the red cell volume to return to the value observed before treatment is the same for both groucps of inice. The cell volume at which new erythrocytes are again released into the circulation depends upon the genotype of functioning blood-forming tissue. Injections of erythropoietin stimulate red cell formation in polycythemic ww mice, but have much less (if any) effect upon polycythemic WW(T) mice. 相似文献
14.
以鸡蛋清为原料,探究在25 ℃贮藏期间蛋清中主要蛋白质含量和流变特性等指标的变化。结果表明:随着贮藏时间延长,卵黏蛋白含量显著(P<0.05)降低;S-卵白蛋白含量显著(P<0.05)增加,至28 d时含量达到(92.99±0.81)%;溶菌酶含量呈现显著(P<0.05)的先升高后降低的趋势,但其活力趋于下降。随着蛋白质含量的变化,蛋清的起泡性和乳化性呈现显著(P<0.05)的先增高后降低的变化,而泡沫稳定性和乳化稳定性则显著(P<0.05)降低。贮藏过程中蛋清的热变性温度与热焓值逐渐增高。在贮藏前期,蛋清的表观黏度增加,贮能模量(G')>耗能模量(G″),表现为流体的弹性性质;在贮藏后期,蛋清的表观黏度减小,G'相似文献
15.
采用统计力学模型对气液两相流体的粘滞系数进行了研究。认为这种模型比一般的液体理论方法直观和简洁,能更好地分析和计算两相流的粘度与其温度、流压及含气率的关系。研究中发现气液两相流体的粘度不仅与温度和含气量有关,而且还受到压强的影响,即随着含气率的增加,压强对粘度的影响越来越显著。对含气水溶液进行的计算表明,粘度随溶液含气量的增多而下降,随溶液流压的升高而增大。将计算结果与重水及稀溶液的实验值进行了比较,结果表明,理论计算结果的误差不超过10％。 相似文献
16.
蜂胶柠檬酸保鲜液对蜂王幼虫的保鲜效果 总被引：1，自引：0，他引：1
采用不同体积分数的蜂胶乙醇提取物和柠檬酸配制成保鲜液 ,进行蜂王幼虫保鲜试验 .结果表明 ,含蜂胶乙醇提取物 0 .1%和柠檬酸 0 .5%的保鲜液综合效果最理想 ,蜂王幼虫于常温下浸没保存于其中 7d,虫体挥发性盐基氮值 (VBN)仍小于 150 mg· kg-1,相当于肉类和鱼类的一级新鲜度 ;浸没保存于其中 14d,虫体VBN值还未超过 2 50 mg· kg-1,相当于肉类和鱼类的二级新鲜度 相似文献
17.
Rees CW 《Science (New York, N.Y.)》1927,66(1699):89-91
It has been shown that trophozoites of balantidia from the pig are normal in appearance and reactions when the medium is cooled to room temperature. They may live at room temperature for ten days. Trophozoites that infect the pig may pass through the stomach of the guinea-pig and reach the cecum, where they are normal after eighteen hours. Trophozoites are frequently passed in feces by the pig but cyst production is irregular and determined by unknown factors as in monkeys, guinea-pigs and man. The fluid of pig feces from the cecum is slightly hypertonic to blood serum. The method of Barret and Yarbrough for the cultivation of Balantidium coli has been found practicable for Balantidium from the pig and guinea-pig. The addition of rice starch improves the medium and Ringer's solution without dextrose was found more suitable than 0.5 per cent. NaCl solution. Loeffler's beef blood serum may be substituted for human serum or horse serum. H(2)S appears non-toxic to Balantidium from the pig when passed into culture tubes. 相似文献
18.
高钴负荷对肉仔鸡血液粘度的影响及其与肉鸡腹水综合征发生发展的关系 总被引：1，自引：0，他引：1
300只AA肉仔鸡平均分成两组,一组为对照组,另一组为高钴负荷组（从5日龄起饮含钴80mg／L的水）。于5,30和45日龄每组随机抽取20只鸡,分别检测红细胞压积（PCV）、红细胞计数（RBC）、血红蛋白浓度（HB）、全血比粘度（BRV）和腹水心脏指数（AHI）;45日龄时扑杀所有试验鸡,观察腹水综合征发生情况。结果为：（1）高钴负荷鸡在30和45日龄时其PCV,RBC和HB显著高于对照鸡（P＜0．05）;（2）30和45日龄时高钴负荷鸡的BRV极显著高于对照鸡（P＜0．01）;（3）30和45日龄时高钴负荷鸡的AHI显著大于对照鸡（P＜0．05）,45日龄时高钴负荷鸡的腹水检出率倍增于对照鸡。本试验表明高钴负荷可诱发肉仔鸡红细胞增生,进而使血液粘度升高,最终导致右心肥大－腹水综合征。 相似文献
19.
为研究鲑鳟鱼的血细胞形态学差异,采用光镜及电镜技术对白点鲑Salvelinus malma(体质量49.07 g±12.05 g)、红点鲑Salvelinus leucomaenis(体质量83.23 g±15.07 g)、虹鳟Oncorhynchus mykiss(体质量60.12 g±11.86 g)和金鳟Oncorhynchus mykiss(体质量42.04 g±10.26 g)4种鲑鳟鱼外周血细胞的组成、大小、显微及超微结构进行了研究。结果表明:4种鲑鳟鱼外周血细胞中可见红细胞、淋巴细胞、嗜中性粒细胞、血栓细胞及单核细胞,其中,红细胞占大多数,淋巴细胞数量仅次于红细胞,大淋巴细胞和嗜中性粒细胞密度在4种鲑鳟鱼中无显著性差异(P>0.05);4种鲑鳟鱼的成熟红细胞形态结构相似,血栓细胞形态多样,其他种类白细胞形态结构相似,白细胞均以血栓细胞和淋巴细胞为主体;白点鲑血栓细胞最多,成群结队排列,红细胞数量也较多,红细胞长径和短径均最大,单核细胞中富含细胞器,嗜中性粒细胞分叶较多;红点鲑红细胞和淋巴细胞数量也较多;虹鳟红细胞密度最小,淋巴细胞最多,嗜中性粒细胞长径和短径最大;金鳟红细胞和白细胞密度最大,淋巴细胞和血栓细胞长径和短径最大。研究表明,4种鲑鳟鱼外周血细胞的显微和超微结构特征与其他鱼类相似,但不同物种间血细胞数量和大小存在一定差异。 相似文献
20.
Plasmodium falciparum malaria: band 3 as a possible receptor during invasion of human erythrocytes 总被引：7，自引：0，他引：7
Human erythrocyte band 3, a major membrane-spanning protein, was purified and incorporated into liposomes. These liposomes, at nanomolar concentrations of protein, inhibited invasion of human erythrocytes in vitro by the malaria parasite Plasmodium falciparum. Liposomes containing human band 3 were ten times more effective in inhibiting invasion than those with pig band 3 and six times more effective than liposomes containing human erythrocyte glycophorin. Liposomes alone or liposomes containing erythrocyte glycolipids did not inhibit invasion. These results suggest that band 3 participates in the invasion process in a step involving a specific, high-affinity interaction between band 3 and some component of the parasite. 相似文献