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91.
M. K. Agarwal Ph.D. R. T. Jones B.S. J. W. Yunginger M.D. 《The Journal of allergy and clinical immunology》1982,70(6):437-444
To develop a model for mold allergen extract standardization, we studied eight commercial Alternaria extracts from various suppliers by a variety of immunochemical and physicochemical techniques, including measurement of Alt-I, a purified allergenic fraction of Alternaria. Wide variations were noted in the allergenic and antigenic potencies of these extracts. Estimates of Alt-I content measured by Alt-I RAST inhibition and by radioimmunoassay correlated significantly (p < 0.05), but Alt-I activity by either method could not be correlated with allergenic potency as measured by RAST inhibition using solid-phase Alternaria. Each test extract produced unique and differing patterns of Coomassie blue-stained bands in isoelectrofocusing gels and in crossed immunoelectrophoresis gels using rabbit antibodies to Alternaria. The optimal method for mold allergen standardization involves a combination of RAST inhibition, isoelectrofocusing, and crossed immunoelectrophoresis techniques, and, if possible, quantitation of individual allergens. 相似文献
92.
Yoshihiro Kikkawa Hideki Abe Masahiro Fujita Tadahisa Iwata Yoshio Inoue Yoshiharu Doi 《Macromolecular chemistry and physics.》2003,204(15):1822-1831
Direct visualization of crystal growth in poly(L ‐lactide) thin films was carried out by using a temperature‐controlled atomic force microscopy (AFM). At the initial stage of crystallization, edge‐on lamellar crystals have nucleated and elongated. Subsequently, the edge‐on lamellar crystals showed S‐shaped morphology and changed their orientation from edge‐on manner to flat‐on one. The curvature of edge‐on lamellar crystal has been discussed in terms of inclination and distortion of polymer chains in the crystal. In addition, mechanism on the formation of flat‐on crystal from edge‐on lamellae was proposed as derivative growth on the basis of in situ AFM observation of crystal growth and enzymatic degradation.
93.
Jehane Fadlallah Delphine Sterlin Claire Fieschi Christophe Parizot Karim Dorgham Hela El Kafsi Gaëlle Autaa Pascale Ghillani-Dalbin Catherine Juste Patricia Lepage Marion Malphettes Lionel Galicier David Boutboul Karine Clément Sébastien André Florian Marquet Christophe Tresallet Alexis Mathian Guy Gorochov 《The Journal of allergy and clinical immunology》2019,143(4):1575-1585.e4
94.
Labeling of cells with ferumoxides-protamine sulfate complexes does not inhibit function or differentiation capacity of hematopoietic or mesenchymal stem cells 总被引:12,自引:0,他引:12
Arbab AS Yocum GT Rad AM Khakoo AY Fellowes V Read EJ Frank JA 《NMR in biomedicine》2005,18(8):553-559
Two FDA-approved agents, ferumoxides (Feridex), a suspension of superparamagnetic iron oxide (SPIO) nanoparticles and protamine sulfate, a drug used to reverse heparin anticoagulation, can be complexed and used to label cells magnetically ex vivo. Labeling stem cells with ferumoxides-protamine sulfate (FePro) complexes allows for non-invasive monitoring by MRI. However, in order for stem cell trials or therapies to be effective, this labeling technique must not inhibit the ability of cells to differentiate. In this study, we examined the effect of FePro labeling on stem cell differentiation. Viability, phenotypic expression and differential capacity of FePro labeled CD34 + hematopoietic stem cells (HSC) and mesenchymal stem cells (MSC) were compared with unlabeled control cells. Colony-forming unit (CFU) assays showed that the capacity to differentiate was equivalent for labeled and unlabeled HSC. Furthermore, labeling did not alter expression of surface phenotypic markers (CD34, CD31, CXCR4, CD20, CD3 and CD14) on HSC, as measured by flow cytometry. SDF-1-induced HSC migration and HSC differentiation to dendritic cells were also unaffected by FePro labeling. Both FePro-labeled and unlabeled MSC were cultured in chondrogenesis-inducing conditions. Alcian blue staining for proteoglycans revealed similar chondrogenic differentiation for both FePro-labeled and unlabeled cells. Furthermore, collagen X proteins, indicators of cartilage formation, were detected at similar levels in both labeled and unlabeled cell pellets. Prussian blue staining confirmed that cells in labeled pellets contained iron oxide, whereas cells in unlabeled pellets did not. It is concluded that FePro labeling does not alter the function or differentiation capacity of HSC and MSC. These data increase confidence that MRI studies of FePro-labeled HSC or MSC will provide an accurate representation of in vivo trafficking of unlabeled cells. 相似文献
95.
de Ruiter CJ Elzinga MJ Verdijk PW van Mechelen W de Haan A 《Pflügers Archiv : European journal of physiology》2004,447(4):436-444
The purpose of the present study was to relate the expected inter-subject variability in voluntary drive of the knee extensor muscles during a sustained isometric contraction to the changes in firing rates of single motor units. Voluntary activation, as established with superimposed electrical stimulation was high (range: 91–99%, n=8) during a short maximal contraction, but was lower (range: 69–100%) in most subjects at the point of force failure during a sustained (49.1±10.1 s) fatiguing contraction at 50% of maximum force. On a different experimental day the firing behaviour of 27 single motor units was recorded with wire electrodes in the vastus lateralis muscle, 24 of which could be monitored from the time of recruitment to the point of force failure (53.6±9.8 s). Motor unit firing behaviour differed considerably among subjects. During the second half of the sustained, fatiguing contraction the changes in firing rate firing rate variability of early recruited units ranged from –10% to +100% and from –50% to +160% respectively among subjects. There were significant positive linear relations between voluntary activation, on the one hand, and rectified surface electromyogram (rsEMG, r=0.82), the changes in motor unit firing rate (r=0.49) and firing rate variability (r=0.50) towards the point of force failure on the other. The present data suggest that differences in voluntary drive that appear among subjects during fatigue may be an important determinant of motor unit firing behaviour.Abbreviations
EMG
electromyogram
-
ER unit
early recruited unit
-
MFGC
maximal force-generating capacity
-
MPF
mean power frequency
-
MVC
maximum voluntary contraction
-
NR unit
newly recruited unit
-
rsEMG
rectified surface electromyogram
-
SMUAP
single motor unit action potential 相似文献
96.
A. A. M. Tax J. J. Denier van der Gon C. C. A. M. Gielen C. M. M. van den Tempel 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1989,76(1):55-63
Summary We have compared muscle activation in the control of slow isotonic movements and isometric contractions. Specific attention has been given to the contribution of the two force-grading mechanisms, the recruitment of motor units and the modulation of firing frequency in motor units that have already been recruited. The recruitment order of the m. biceps motor units under study was the same during isometric contractions and slow isotonic movements. However, the recruitment thresholds of the m. biceps units were considerably lower for both isotonic flexion and extension movements, even at velocities as low as 2 deg/s, than for isometric contractions. Furthermore, firing frequency at recruitment was found to depend on the motor task: at recruitment the motoneurone starts firing with a higher firing frequency during isotonic flexion movements and a lower firing frequency during isotonic extension movements than during isometric contractions. Two main conclusions can be drawn from these results. First of all, the concept of one single activation parameter (total synaptic drive?) cannot account for the motor-unit behaviour observed during our experiments: the relative contribution of the two forcegrading mechanisms is different for different tasks. Secondly, the distribution of activity among flexor motoneurone pools is different for isometric contractions and isotonic movements. 相似文献
97.
In an unselected series of 488 patients with head injuries referred to a general surgical department, there were 126 children aged 0–19 years whose head injuries were a result of traffic accidents. In age group 0–4 years, only 23% of the head injuries were due to traffic accidents. In age groups 5–9, 10–14, and 15–19 years, however, traffic accidents were the main cause of the injuries, being responsible for 47%, 65% and 82% of the cases respectively. Both age groups 5–9 and 10–14 years had an unusually high proportion of bicycle injuries, while motorcycle and automobile accidents were the leading causes of injury in age group 15–19 years. Eight children (6%) died as a result of head trauma. Furthermore, among the survivors there were 8 children with severe head injuries (post-traumatic amnesia lasting 24 h), the rest being minor head injuries. All the survivors but one returned to school and achieved reasonable performances. Repeated follow-up studies at 3 months, 1 and 5 years, including interviews with the parents, disclosed that several of the children had headache, dizziness and other complaints. These subjective complaints subsided with time, but with different patterns, in the younger and older age groups. It is concluded that the postconcussional syndrome is not uncommon in children, but it may be better tolerated and resolves more completely with time than in adults. Eight children (7%) had one seizure or more during the 5-year follow-up period. 相似文献
98.
电刺激杏仁核对猫丘脑后核内脏大神经诱发放电的抑制作用 总被引:2,自引:0,他引:2
本文使用条件—检验刺激技术,研究了电刺激杏仁皮质内侧核对猫丘脑后核内脏大神经诱发放电的影响。电刺激杏仁皮质内侧核抑制丘脑后核的中等和长潜伏期内脏大神经诱发放电呈现两种形式:即时抑制和迟发抑制。前者可能是通过从杏仁核到丘脑后核的神经通路产生的,静脉注射纳洛酮可消除这种抑制,提示有鸦片样物质的参与。后者可能涉及神经—体液性因素。结果提示,杏仁核参与抑制内脏痛。 相似文献
99.
100.
摘 要:目的:研究甘肃省靖远县乙型病毒性肝炎 (简称乙肝) 母婴传播阻断措施的实施情况及效果,为进一步探索乙
肝防控策略、制订乙肝防控措施提供建议。方法:调查2016年10月1日—2017年10月31日期间靖远县所有助产机构入院分
娩的乙型肝炎表面抗原 (HBsAg) 阳性产妇所生的新生儿,并对新生儿进行随访,检测其HBsAg 和乙型肝炎表面抗体 (HB?
sAb)。结果:研究共纳入 HBsAg 阳性住院产妇所生新生儿 131 名,其在出生 24 h 内全部进行了乙肝免疫球蛋白 (HBIG)
和乙肝疫苗首针 (HepB1) 接种。新生儿乙肝病毒指尖血检测结果显示,HBsAg 阳性者 1 人,母婴阻断失败率为 0.76%
(1/131);HBsAb阳性者 101人,母婴阻断成功率为 77.10% (101/131);HBsAg和 HBsAb全部阴性者 29人,母婴阻断成功但
免疫失败率为22.14% (29/131)。结论:乙肝疫苗联合免疫球蛋白阻断乙肝母婴传播措施实施情况较好,阻断HBsAg 阳性母
亲垂直传播乙肝病毒效果显著。 相似文献