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1.
Enzyme replacement in Fabry's disease, an inborn error of metabolism   总被引:12,自引:0,他引:12  
Two patients with Fabry's disease were infused with normal plasma to provide active enzyme (ceramide trihexosidase) for hydrolysis of the plasma substrate, galactosylgalactosylglucosylceramide. Maximum ceramide trihexosidase activity occurred 6 hours after infusion of the plasma, attaining a level approximately 150 percent of that in normal plasma; enzymatic activity was detectable for 7 days. The amount of accumulated substrate in the plasma of these recipients decreased about 50 percent on day 10 after infusion. Thus, periodic replacement of ceramide trihexosidase activity in the plasma of patients with Fabry's disease might lead to consistently lower amounts of substrate in the plasma and a decrease in its rate of accumulation in tissues.  相似文献   

2.
为探寻环境友好的秸秆预处理方法,提高秸秆等生物质资源的利用效率,以水稻秸秆为原料,采用3种不同的低温等离子体装置:灭菌柜、介质阻止放电及射频电容耦合对其进行预处理,分别对3种方法的处理条件进行优化,并在此基础上考察预处理后秸秆对纤维素酶的吸附能力及纤维素和半纤维素的糖化效率。结果表明,与未处理的秸秆对照相比,3种方法均可以降低水稻秸秆对纤维素酶的吸附能力,同时提高秸秆中纤维素和半纤维素的糖化率;其中,介质阻挡空气放电对秸秆的处理效果最好,秸秆对酶的吸附率比未处理秸秆的对照组降低了67.6%,而纤维素和半纤维素的糖化率分别比未处理秸秆的对照组提高了34.6%和44.7%。该研究为今后利用低温等离子体预处理秸秆相关技术的改进和深入研究提供了参考。  相似文献   

3.
The tokamak is a prototype fusion device in which a toroidal Magnetic field is used to confine a hot plasma. Coherent waves, excited near the plasma edge, can be used to transport energy into the plasma in order to heat it to the temperatures required for thermonuclear fusion. In addition, tokamak plasmas are known to exhibit high levels of turbulent density fluctuations, which can transport particles and energy out of the plasma. Recently, experiments have been conducted to elucidate the nature of both the coherent waves and the turbulence. The experiments provide insight into a broad range of interesting linear and nonlinear plasma phenomena and into many of the processes that determine such practical things as plasma heating and confinement.  相似文献   

4.
Pituitary halves incubated in pituitary stalk plasma release more luteinizing hormone than their opposite halves incubated in plasma from peripheral blood. Glands incubated in stalk plasma from dopamine-treated rats release more luteinizing hormone than glands incubated in stalk plasma from untreated controls. Luteinizing hormone-releasing activity in stalk plasma may be due to the luteinizing hormone-releasing factor, and the secretion of luteinizing hormone-releasing factor may be controlled by a dopaminergic mechanism.  相似文献   

5.
目的 制备活血散结方含药血浆,并研究其不同浓度对视网膜色素上皮(retinal pigment epithelium,RPE)细胞的毒性作用。方法 以成年健康家兔为对象,制备活血散结方含药血浆。将提取的兔原代RPE细胞分9个组,分别为:空白对照组、正常血浆组、5%含药血浆组、10%含药血浆组、20%含药血浆组、40%含药血浆组、60%含药血浆组、80%含药血浆组、100%含药血浆组,予以相对应浓度的含药血浆干预,CCK8法检测含药血浆对兔RPE细胞毒作用。结果 活血散结方各浓度含药血浆对RPE细胞有抑制作用,其中5%~20%含药血浆对RPE细胞有较弱的抑制作用,但与正常血浆比较,抑制率差异无统计学意义(P>0.05);而40%~100%含药血浆对RPE细胞生长有明显的抑制作用,与正常血浆比较,抑制率差异有统计学意义(P<0.05)。结论 活血散结方含药血浆对RPE细胞有一定的抑制作用,抑制程度与含药血浆浓度成量效关系,可以考虑选择5%~20%含药血浆浓度作为后续实验研究的干预浓度。  相似文献   

6.
The plasma science experiment on Voyager 2 made observations of the plasma environment in Neptune's magnetosphere and in the surrounding solar wind. Because of the large tilt of the magnetic dipole and fortuitous timing, Voyager entered Neptune's magnetosphere through the cusp region, the first cusp observations at an outer planet. Thus the transition from the magnetosheath to the magnetosphere observed by Voyager 2 was not sharp but rather appeared as a gradual decrease in plasma density and temperature. The maximum plasma density observed in the magnetosphere is inferred to be 1.4 per cubic centimeter (the exact value depends on the composition), the smallest observed by Voyager in any magnetosphere. The plasma has at least two components; light ions (mass, 1 to 5) and heavy ions (mass, 10 to 40), but more precise species identification is not yet available. Most of the plasma is concentrated in a plasma sheet or plasma torus and near closest approach to the planet. A likely source of the heavy ions is Triton's atmosphere or ionosphere, whereas the light ions probably escape from Neptune. The large tilt of Neptune's magnetic dipole produces a dynamic magnetosphere that changes configuration every 16 hours as the planet rotates.  相似文献   

7.
Prorenin in high concentrations in human ovarian follicular fluid   总被引:11,自引:0,他引:11  
Although the kidney is a major source of prorenin, the precursor of renin, there are extrarenal sources for plasma prorenin that have not been identified. The selective increase in plasma prorenin at the time of ovulation suggested that one of these sources might be the ovary. Prorenin was therefore measured in fluid aspirated from 18 ovarian follicles and in plasma collected from three women who were undergoing in vitro fertilization. The follicular fluid contained high concentrations of prorenin that were approximately 12 times higher than plasma prorenin. The prorenin from follicular fluid was immunochemically identical to kidney and plasma prorenin. Thus, the ovary is a likely source for the ovulatory peak of plasma prorenin.  相似文献   

8.
Observations with the Venus Express magnetometer and low-energy particle detector revealed magnetic field and plasma behavior in the near-Venus wake that is symptomatic of magnetic reconnection, a process that occurs in Earth's magnetotail but is not expected in the magnetotail of a nonmagnetized planet such as Venus. On 15 May 2006, the plasma flow in this region was toward the planet, and the magnetic field component transverse to the flow was reversed. Magnetic reconnection is a plasma process that changes the topology of the magnetic field and results in energy exchange between the magnetic field and the plasma. Thus, the energetics of the Venus magnetotail resembles that of the terrestrial tail, where energy is stored and later released from the magnetic field to the plasma.  相似文献   

9.
We show that the plasma and magnetic fields in the inner region of Saturn's plasma disk rotate in synchronism with the time-variable modulation period of Saturn's kilometric radio emission. This relation suggests that the radio modulation has its origins in the inner region of the plasma disk, most likely from a centrifugally driven convective instability and an associated plasma outflow that slowly slips in phase relative to Saturn's internal rotation. The slippage rate is determined by the electrodynamic coupling of the plasma disk to Saturn and by the drag force exerted by its interaction with the Enceladus neutral gas torus.  相似文献   

10.
Additional plasma measurements in the vicinity of Venus are presented which show that (i) there are three distinct plasma electron populations-solar wind electrons, ionosheath electrons, and nightside ionosphere electrons; (ii) the plasma ion flow pattern in the ionosheath is consistent with deflected flow around a blunt obstacle; (iii) the plasma ion flow velocities near the downstream wake may, at times, be consistent with the deflection of plasma into the tail, closing the solar wind cavity downstream from Venus at a relatively close distance (within 5 Venus radii) to the planet; (iv) there is a separation between the inner boundary of the downstream ionosheath and the upper boundary of the nightside ionosphere; and (v) during the first 4.5 months in orbit the measured solar wind plasma speed continued to vary, showing a number of high-speed, but generally nonrecurrent, streams.  相似文献   

11.
The first of at least nine bow shock crossings observed on the inbound pass of Voyager 2 occurred at 98.8 Jupiter radii (R(J)) with final entry into the magnetosphere at 62 R(J). On both the inbound and outbound passes the plasma showed a tendency to move in the direction of corotation, as was observed on the inbound pass of Voyager 1. Positive ion densities and electron intensities observed by Voyager 2 are comparable within a factor of 2 to those seen by Voyager 1 at the same radial distance from Jupiter; the composition of the magnetospheric plasma is again dominated by heavy ions with a ratio of mass density relative to hydrogen of about 100/1. A series of dropouts of plasma intensity near Ganymede may be related to a complex interaction between Ganymede and the magnetospheric plasma. From the planetary spin modulation of the intensity of plasma electrons it is inferred that the plasma sheet is centered at the dipole magnetic equator out to a distance of 40 to 50 R(J) and deviates from it toward the rotational equator at larger distances. The longitudinal excursion of the plasma sheet lags behind the rotating dipole by a phase angle that increases with increasing radial distance.  相似文献   

12.
为探究奶牛血浆催乳素(Prolactin, PRL)浓度的群体特征及其在不同环境条件和生理阶段下的变化规律,估计牛血浆PRL浓度的遗传参数,探究PRL、PRLR和TRH基因多态性与血浆PRL浓度之间的相关性,本研究于2014和2017年对北京地区某规模化牧场的472头泌乳期荷斯坦牛进行血浆PRL浓度测定,共获得1 169条数据。首先,采用固定模型分析采样季节、胎次、挤奶前后和泌乳阶段对奶牛血浆PRL浓度的影响;然后,采用重复力动物模型估计血浆PRL浓度的遗传参数;此外,通过扫描PRL、PRLR和TRH基因的多态位点,对血浆PRL浓度进行基于多态位点和单倍型的关联分析。结果显示:1)泌乳期荷斯坦牛血浆PRL平均浓度为224.29 mIU/L,胎次、采样季节和泌乳阶段对血浆PRL浓度有显著或极显著影响,血浆PRL浓度随胎次和泌乳阶段的推移而逐渐升高,春季和夏季时奶牛血浆PRL浓度极显著高于秋季和冬季(P<0.01);2)血浆PRL浓度的遗传力为0.02,为低遗传力性状;3)PRL和PRLR基因基因中未发现与血浆PRL浓度显著相关的SNP位点,TRH基因的rs137596325、rs1...  相似文献   

13.
Extensive measurements of low-energy positive ions and electrons in the vicinity of Uranus have revealed a fully developed magnetosphere. The magnetospheric plasma has a warm component with a temperature of 4 to 50 electron volts and a peak density of roughly 2 protons per cubic centimeter, and a hot component, with a temperature of a few kiloelectron volts and a peak density of roughly 0.1 proton per cubic centimeter. The warm component is observed both inside and outside of L = 5, whereas the hot component is excluded from the region inside of that L shell. Possible sources of the plasma in the magnetosphere are the extended hydrogen corona, the solar wind, and the ionosphere. The Uranian moons do not appear to be a significant plasma source. The boundary of the hot plasma component at L = 5 may be associated either with Miranda or with the inner limit of a deeply penetrating, solar wind-driven magnetospheric convection system. The Voyager 2 spacecraft repeatedly encountered the plasma sheet in the magnetotail at locations that are consistent with a geometric model for the plasma sheet similar to that at Earth.  相似文献   

14.
The plasma wave instrument on the International Cometary Explorer (ICE) detected bursts of strong ion acoustic waves almost continuously when the spacecraft was within 2 million kilometers of the nucleus of comet Giacobini-Zinner. Electromagnetic whistlers and low-level electron plasma oscillations were also observed in this vast region that appears to be associated with heavy ion pickup. As ICE came closer to the anticipated location of the bow shock, the electromagnetic and electrostatic wave levels increased significantly, but even in the midst of this turbulence the wave instrument detected structures with familiar bow shock characteristics that were well correlated with observations of localized electron heating phenomena. Just beyond the visible coma, broadband waves with amplitudes as high as any ever detected by the ICE plasma wave instrument were recorded. These waves may account for the significant electron heating observed in this region by the ICE plasma probe, and these observations of strong wave-particle interactions may provide answers to longstanding questions concerning ionization processes in the vicinity of the coma. Near closest approach, the plasma wave instrument detected broadband electrostatic noise and a changing pattern of weak electron plasma oscillations that yielded a density profile for the outer layers of the cold plasma tail. Near the tail axis the plasma wave instrument also detected a nonuniform flux of dust impacts, and a preliminary profile of the Giacobini-Zinner dust distribution for micrometer-sized particles is presented.  相似文献   

15.
冷源等离子体是气体在高电压作用下高度电离的混合物,混合物中多种活性基团和粒子能够与微生物体中的多种成分发生发应,从而阻碍微生物的正常生长,最终导致死亡,反应过程中温度无明显变化。冷源等离子体作为一种冷杀菌方法,在食品杀菌工业中具有广阔的应用前景。对冷源等离子体的发生、产生系统以及等离子体中的活性作用物质进行了综述,并介绍了冷源等离子体在食品中的应用研究。  相似文献   

16.
Comparison of genomic DNA sequences from human and mouse revealed a new apolipoprotein (APO) gene (APOAV) located proximal to the well-characterized APOAI/CIII/AIV gene cluster on human 11q23. Mice expressing a human APOAV transgene showed a decrease in plasma triglyceride concentrations to one-third of those in control mice; conversely, knockout mice lacking Apoav had four times as much plasma triglycerides as controls. In humans, single nucleotide polymorphisms (SNPs) across the APOAV locus were found to be significantly associated with plasma triglyceride levels in two independent studies. These findings indicate that APOAV is an important determinant of plasma triglyceride levels, a major risk factor for coronary artery disease.  相似文献   

17.
Selective phospholipid adsorption and atherosclerosis   总被引:1,自引:0,他引:1  
Disaturated (fully saturated) lecithins adsorb onto solid surfaces more readily than lecithins in which one or both fatty acids are unsaturated. If saturated lecithins adsorb to arterial walls as they do to glass and polystyrene surfaces, there may be increased probability of atherosclerosis when the disaturated lecithin content of plasma is elevated. Analyses of lecithins in plasma samples from patients with myocardial infarction, and from patients with premature atherosclerosis but with low concentrations of plasma cholesterol and triglycerides, are consistent with the hypothesis that a high concentration of disaturated lecithin in plasma may be a significant risk factor for atherosclerosis, independent of triglyceride and cholesterol concentrations.  相似文献   

18.
基于Cap-cyclide坐标的非圆截面等离子体的稳定性研究   总被引:3,自引:1,他引:2  
通过导人Cap-cyclide坐标,进行了导体壁对非圆截面等离子体稳定性影响的研究,得出了等离子体的稳定性随着导体壁接近等离子体的表面而增加这一结论。  相似文献   

19.
李杰  刘国勋 《湛江医学院学报》1996,14(2):103-104,112
用ELISA双抗体夹心法动态检测观察了心脏机械瓣膜置换术患者32例术前、术后60天内的血浆中D二聚体变化,结果表明:术前D二聚体高于正常,但在术后D二聚体浓度持续增高,7 ̄10天达到高峰,60天内降至正常水平,与术前比较差异有显著意义(P〈0.01),本文对换瓣术后患者血浆D二聚体变化的规律作了分析,并对其临床意义作了讨论。  相似文献   

20.
冷等离子体对单核增生李斯特菌的杀菌机理   总被引:1,自引:0,他引:1  
【目的】作为一种新兴的非热灭菌技术,冷等离子在食品行业中得到了广泛的应用。通过探讨冷等离子体对细菌细胞膜的破坏效果,阐述其抗菌机制,为冷等离子体在食品行业的应用提供参考。【方法】本研究以单核增生李斯特菌(Listeria monocytogenes,LM)为试验菌株,研究冷等离子体处理对LM形态和胞内物质的影响,阐述LM细胞膜完整性的变化;冷等离子体处理后,通过测定细胞膜脂肪酸含量和类型的变化,比较8-苯胺-1-萘磺酸荧光强度的改变,反映冷等离子体对LM细胞膜流动性的影响。通过测定碘化丙啶荧光、电导率和β-半乳糖苷酶活性的变化,观察冷等离子体对LM细胞膜通透性的改变。最后,通过检测胞内活性氧和活性氧相关基因表达量的变化,阐明冷等离子体对LM细胞膜造成的氧化损伤。【结果】冷等离子体处理后,LM细胞膜表面观察到破损变形的结构,胞内蛋白质和DNA分别下降了68 mg?mL-1和14 μg?mL -1,证明冷等离子体破坏了细胞膜的完整性。冷等离子体处理使LM细胞膜中不饱和脂肪酸的含量从40.17%上升至53.91%,饱和脂肪酸的含量从53.68%下降到41.57%,8-苯胺-1-萘磺酸荧光强度从8.99下降到3.73,说明冷等离子体处理后细胞膜的流动性增加。此外,冷等离子体处理后,碘化丙啶可以透过细胞膜,与胞内遗传物质结合发出红色荧光,电导率由0.15 mS?cm-1上升至0.33 mS?cm-1,β-半乳糖苷酶活性也发生了明显的变化,OD420nm从0.274提高至0.683,说明LM细胞膜通透性提高。胞内活性氧(reactive oxygen species,ROS)荧光和荧光强度的变化说明,冷等离子体刺激细胞膜上ROS的产生,因此对细胞膜造成了氧化损伤。qRT-PCR结果显示冷等离子体处理下调了perRrecA的相对表达量,分别下降43.29%和52.71%,而sigB的相对表达量上调了89.42%,揭示冷等离子体处理条件下,微生物在基因层面的氧化应激和调控机制。【结论】冷等离子体的活性基团通过对细胞膜的作用,破坏LM的细胞活性,起到了抑制效果。  相似文献   

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