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991.
本实验通过结扎兔冠状动脉左室支复制动脉缺血-再灌注模型,应用心外膜接触电极记录单相动作电位,观察后除极电位在再灌注性心律失常中及镁离子的拮抗作用。结果表明,再灌性心律失常的52.6%与早期后去极化有关。硫酸镁可终止及预防RA,对再灌中出现触发活动有抑制作用。  相似文献   
992.
The rate of release of five amino acids (alanine, glutamine, glutamic acid, glycine, GABA) from the surface of the sensorimotor cortex has been determined in rabbits under local anesthesia immobilized with gallamine. Concomitant recording of the electroencephalogram and of blood pressure has been carried out. The scope of the research was to determine if a difference in the release of these aminoacids could be correlated with variations in cerebral electrical activity. Two open-ended silver cylinders were adapted to the cortex and filled with saline. Every 10 min, the liquid was removed and assayed using a dansylating procedure followed by thin layer chromatographic separation and fluorimetric determination of the amino acids. The EEG of non treated animals, followed for a period of 100 min, remained synchronized for the majority of the recording; the biochemical determinations indicated a slight but constant fall in the rate of release of all the amino acids. A significant increase in the release accompanied the EEG desynchronisation induced either with eserine (0.2 mg/kg), amphetamine (2 mg/kg), or with electrical stimulation of the reticular formation.  相似文献   
993.
Idiopathic thrombocytopenic purpura (ITP) is a frequent platelet disorder due to the presence of anti-platelet autoantibodies. Recently a fibronectin/fibrinogen receptor in platelets, integrin GPIIb/IIIa, has been implicated as the antigen in chronic ITP. To examine the epitopes involved in the autoimmune response against GPIIb/IIIa we have used concepts from the complementary hydropathy principle. We used the peptide Trp-Thr-Val-Pro-Thr-Ala, WTVPTA (deduced from the complementary nucleotide sequence to that which codes for the Arg-Gly-Asp, RGD, domain in fibronectin), to test the immunologic activity of ITP sera. Sera from 31 patients with clinically defined ITP were tested in ELISA for reactivity towards WTVPTA and affinity purified GPIIb/IIIa. Seventeen sera (57%) reacted strongly with the glycoprotein complex, five of which reacted with the peptide. By affinity chromatography of one of these sera, we were able to show that antibodies that bind to the peptide are within the population that binds to GPIIb/IIIa. Liquid phase competition experiments revealed that binding of ITP serum to WTVPTA was inhibited only by a hydropathically compatible peptide. Our data indicate that autoantibodies can bind to hydropathically generated antigenic determinants and thus, render these peptides clinically important as diagnostic tools.  相似文献   
994.
In this paper we show theoretically that when a magnetised blood bolus enters a CW NMR excitor coil of length Le at resonance and the signal from the T2-decaying, processing transverse magnetisation of the flowing blood spins is subsequently detected by a detector coil of length L separated from the excitor coil by a distance delta l, then by recording CW NMR signals at three positions such as delta l = 0, 0.5 and 1.0 cm one can eliminate the static tissue signal and measure non-invasively the steady component V0 as well as the total vessel cross section, beta accurately. The time dependent part of the CW NMR signal which depends on Vpulse(t), is also dependent on V0 non-linearly unless both L and Le are greater than 50 cm and delta l is zero. Finally, methods of obtaining true Vpulse(t) from the CW NMR signal after applying proper correction due to the steady flow are discussed.  相似文献   
995.
本实验采用硫代乙酰胺(thioacetamide,TAA)灌胃复制大鼠急性肝功能衰竭的动物模型。检测血中内毒素、转氨酶、脂蛋白-x等含量以及胆汁流量。结果表明,大鼠发生了肝内胆汁淤积与内毒素血症(ETM),并且两者呈正相关(P<0.05)。同时肝细胞膜上Na -K -ATP酶的活力明显降低,与ETM含量呈负相关(P<0.05)。结果提示:ETM与肝内胆汁淤积的发生有密切关系.  相似文献   
996.
Levels of expression of CD19 and CD20 in chronic B cell leukaemias.   总被引:10,自引:0,他引:10       下载免费PDF全文
AIMS: To investigate whether the antigen levels of the B cell lineage markers CD19 and CD20 can distinguish between normal and neoplastic B cells or characterise distinct expression patterns among the chronic B cell leukaemias. METHODS: Peripheral blood cells from 70 patients with B cell disorders and 17 healthy donors were analysed by quantitative flow cytometry. Direct immunofluorescence staining was performed with phycoerythrin conjugated CD19 and CD20 monoclonal antibodies. Standard microbeads with different capacities to bind mouse immunoglobulins were used to convert the mean fluorescence intensity (MFI) values into number of antigen molecules/cell, expressed as antibody binding capacity (ABC). RESULTS: CD19 and CD20 ABC values in leukaemic B cells differed from those of normal blood B lymphocytes. The results identified distinct profiles of CD19 and CD20 expression in the various types of B cell leukaemias. In all leukaemias studied except hairy cell leukaemia (HCL), CD19 expression was significantly lower than the mean (SD) value in normal B cells (22 (7) x 10(3) molecules/cell), as follows: chronic lymphocytic leukaemia (CLL), 13 (7) x 10(3); B prolymphocytic leukaemia (B-PLL), 16 (9) x 10(3); splenic lymphoma with villous lymphocytes (SLVL), 15 (11) x 10(3); mantle cell lymphoma (MCL), 10 (7) x 10(3). In HCL there was strong CD19 expression (38 (16) x 10(3)). In contrast, the level of expression of membrane CD20 was higher than the mean (SD) value in normal B cells (94 (16) x 10(3) molecules/cell) in MCL (123 (51) x 10(3)); B-PLL (129 (47) x 10(3)); SLVL (167 (72) x 10(3)); and HCL (312 (110) x 10(3)); while it was significantly lower (65 (11) x 10(3)) in CLL compared with normal B cells and the other B cell leukaemias. CONCLUSIONS: Quantitative determination of CD19 and CD20 may provide useful diagnostic information for the study of B lymphoproliferative disorders.  相似文献   
997.
Summary The present report deals with a study of the osmoregulation of young Hymenolepis microstoma using the in vitro cultivation at different osmotic pressures: i.e. in eleven media with freezing point depressions ranging from 0.35 to 1.21° C. It has been shown that H. microstoma is able to develop optimally and equally well in media with freezing point depressions from 0.50 to 0.73° C. The worm seems to have a regulatory system operating successfully between these approximate limits. Media with lower or higher osmotic pressures do not cause death within the present experimental conditions but inhibit development gradually.It is concluded that, although cestodes are regarded as poikilosmotic, the present results with H. microstoma indicate that homoiosmotic properties might exist within a certain limited range of osmotic pressures.Supported by a N.A.T.O. grant.Encouragement by Prof. Dr. C. A. Hopkins is gratefully acknowledged.  相似文献   
998.
Load-bearing tissues, like bone, can be replaced by engineered tissues or tissue constructs. For the success of this treatment, a profound understanding is needed of the mechanical properties of both the native bone tissue and the construct. Also, the interaction between mechanical loading and bone regeneration and adaptation should be well understood. This paper demonstrates that microfocus computer tomography (microCT) based finite element modelling (FEM) can have an important contribution to the field of functional bone engineering as a biomechanical analysis tool to quantify the stress and strain state in native bone tissue and in tissue constructs. Its value is illustrated by two cases: (1) in vivo microCT-based FEM for the analysis of peri-implant bone adaptation and (2) design of biomechanically optimised bone scaffolds. The first case involves a combined animal experimental and numerical study, in which the peri-implant bone adaptive response is monitored by means of in vivo microCT scanning. In the second case microCT-based finite element models were created of native trabecular bone and bone scaffolds and a mechanical analysis of both structures was performed. Procedures to optimise the mechanical properties of bone scaffolds, in relation to those of native trabecular bone are discussed.  相似文献   
999.
Tracheoesophageal vocal prostheses (TVP) in laryngectomized patients commonly deteriorate due to overgrowth by yeasts, particularly Candida species. We describe the first case of colonization of such devices by a member of the Fusarium solani species complex in a patient with a history of glottal carcinoma. Three isolates, from three prostheses, were found morphologically consistent with the traditional picture of F. solani. Ribosomal sequence analysis showed that the isolates belonged to a distinct, as yet apparently unnamed phylogenetic species within the F. solani species complex. This species, one of two distinct genetic types (genotype 2) traditionally considered part of the plant-pathogenic subtaxon Fusarium solani f. sp. radicicola, has not previously been identified as an agent of human or animal disease, although it is closely related to a known etiologic agent of mycetoma, an Acremonium-like species recently renamed Fusarium falciforme. Sequence and multisatellite M13 polymorphism analysis revealed no distinctions among the case isolates. Production of cyclosporine was detected for all three case isolates.  相似文献   
1000.
Natural killer (NK) cell recognition and function in humans is regulated by multiple cell surface receptors. The "on" signal leading to NK cell triggering is primarily mediated by natural cytotoxicity receptors (NCR). Analysis of NK cells in primate animal models is of particular relevance because NK cells may play an essential role in host defenses against infections. We analyzed Macaca fascicularis PBMC and in vitro-derived NK cell populations and clones by cytofluorometry, using a wide panel of mAb, and by cytolytic activity assays. In addition, RT-PCR strategy and transient transfections were used to isolate M. fascicularis NCR. NCR-specific mAb reactivity (anti-NKp46 and anti-NKp30) was present on M. fascicularis PBMC and on NK cell cultures. Macaque NCR were functional in both redirected killing and in mAb-mediated masking assays. Cloning of macNKp46 and macNKp30 NCR homologous genes showed a high sequence similarity (86 % and 88 %, respectively) with their human counterparts. Attempts at identifying NKp44 surface reactivity and at cloning the macaque homologue were unsuccessful. NKp46 and NKp30 NCRs, but not NKp44, are highly conserved in M. fascicularis NK cells. This suggests the possibility of a staged appearance of the NCR during phylogenesis and provides a useful tool for the study of natural immunity correlates of protection in primate SIV/SHIV infection models.  相似文献   
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