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71.
A Hatziefthimiou A Mitsacos E Mitsaki A Plaitakis E D Kouvelas 《Journal of neuroscience research》1991,28(3):367-375
In the present work the distribution of L-glutamate binding sites in the different layers of human cerebellum of normal individuals and of seven patients who died with olivopontocerebellar atrophy (OPCA) was examined with the technique of quantitative autoradiography. Specific L-[3H]glutamate binding was higher in the molecular than in the granule cell layer of normal cerebellar tissue. A significant decrease of L-[3H]glutamate specific binding was observed in the molecular layer of all OPCA tissues. In the granule cell layer L-[3H]glutamate binding was decreased only in two patients who suffered from late-onset sporadic OPCA and in one patient who suffered from a form of OPCA inherited in a dominant manner. Quisqualate-sensitive binding sites were the most abundant binding sites in the molecular layer of normal cerebella, whereas N-methyl-D-aspartic acid (NMDA)-sensitive binding sites were the most abundant type in the granule cell layer. A significant decrease of quisqualate-sensitive and an increase in NMDA-sensitive binding sites were observed in the molecular layer of OPCA cerebellar tissues. No significant changes were observed in the granule cell layer of these tissues. 相似文献
72.
用放免法检测乙型慢性活动性肝炎病人的红细胞c3b受体(KBCCR1).结果:病人RBCCR1明显低于献血员(P<0.05);抗-HBs特异性免疫复合物阳性病人RBCCR1明显低于阴性病人(P<0.01),与红细胞C3b受体花环试验检测结果一致。表明乙型慢性活动性肝炎病人RBCCR1数量减少,活性下降。其原因可能是特异性循环免疫复合物占据了RBCCR1空位,使CR1活性下降。 相似文献
73.
Véronique Strijckmans Michel Bottlaender Humin Luo Michèle Ottavianil Daniel W. McPherson Christian Loc'h Chantal Fuseau Furn F. Knapp Bernard Mazière 《European journal of nuclear medicine and molecular imaging》1997,24(5):475-482
We studied the potential of three radiobrominated isomers of BrQNP, (Z(-,-)-[76Br]BrQNP,E(-,-)-[76Br]BrQNP andE(-,+)-[76Br]BrQNP), as suitable radioligands for imaging of central muscarinic cholinergic receptors in the human brain. These radioligands were stereospecifically prepared by electrophilic radiobromodestannylation of the respective tributylstannyl precursors using no-carrier-added [76Br]BrNH4 and peracetic acid. Preliminary pharmacological characterizations were determined by biodistribution, autoradiography, competition, displacement and metabolite studies in rats. The (-,-)-configuration presented important specific uptakes in brain muscarinic cholinergic receptor (mAChR)-rich structures and in heart, low metabolization rates and an apparent M2 selectivity. The (-,+)-configuration revealed more rapid clearance, lower uptake, a higher metabolization rate and an apparent M1 selectivity. Reversibility of the binding was confirmed for the three radiotracers. Positron emission tomography in the living baboon brain revealed high and rapid uptake in the brain and accumulation in the mAChR-rich structures studied. At 30 min p.i., theE(-,-)-radiotracer reached a plateau in cortex, pons and thalamus with concentrations of 29%, 24% and 19% ID/l, respectively.Z(-,-)-[76Br]BrQNP also accumulated in these structures, reaching a maximal uptake (27% ID/l) in the cortex 2 h p.i. At 5 min p.i. a plateau (17% ID/l) was only observed in the cortex for theE(-,+)-[76Br]BrQNP; by contrast, the other structures showed slow washout. After 3 weeks, the (-,-)-radiotracers were studied in the same baboon pretreated with dexetimide (1 mg/kg), a well-known muscarinic antagonist. In all the mAChR structures, the highly reduced uptake observed after this preloading step indicates that these radiotracers specifically bind to muscarinic receptors.Z(-,-)-[76Br]BrQNP, which is displaced in higher amounts from M2 mAChR-enriched structures, reveals an M2 affinity. The two isomers having the (-,-)-configuration are potential probes for investigating central muscarinic receptors. The absolute configuration on the acetate chiral centre influences their muscarinic subtype selectivity and thecis-trans isomerism of the vinyl moiety affects their specific fixation. 相似文献
74.
Marina Quartu Maria Pina Serra Annalisa Manca Paolo Follesa Rossano Ambu Marina Del Fiacco 《International journal of developmental neuroscience》2003,21(6):309-320
The immunohistochemical occurrence of the high affinity neurotrophin (NT) receptors trkA, trkB, and trkC is shown in the pre-term newborn, infant, and adult human post-mortem cerebellum. Immunoreactive neuronal perikarya and processes were observed in all specimens examined, where they appeared unevenly distributed in the cerebellar cortical layers and deep nuclei, and showed regional differences among cerebellar lobules and folia. The trk receptor-antibodies, tested by Western blot on human cerebellum homogenates, revealed multiple immunoreactive bands for trkA and single bands for trkB and trkC. The results obtained show the tissue localization of the trk receptor-like immunoreactivity in the human cerebellum from prenatal to adult age. The analysis for codistribution of the receptors with the relevant ligand and among the receptors in discrete cortical and deep nuclei tissue fields shows a wide variety of conditions, from a good similarity in terms of type and density of labeled structures, to a lack of correspondence, and suggests the possibility of colocalization of trk receptors with the relevant neurotrophin and among them in the cerebellar cortex. These results sustain the concept that the neurotrophin trophic system participates in the development, differentiation, and maintenance of the human cerebellar connectivity and support the possibility of a multifactorial trophic support for the neurotrophins through target-derived and local mechanisms. 相似文献
75.
E. V. Borisova D. Yu. Rusakov S. K. Sudakov 《Bulletin of experimental biology and medicine》1992,114(3):1328-1332
76.
Summary Insulin binding to trophoblast plasma membranes and the placental glycogen content were measured in twelve healthy women, in eleven well-controlled gestational diabetic women who were treated either with diet alone (n=4) or with insulin (n=7) and in 18 women with well-controlled overt diabetes mellitus (six White B; four White C; eight White D). The competitive binding assay was carried out with 22 concentrations of unlabelled insulin. Binding data were analysed by a non-linear direct model fitting procedure assuming one non-cooperative binding site. Maximum specific binding was unchanged in the total collective of gestational diabetic women, but was decreased by 30% in those treated with diet (6.2±2.2%) and increased by 90% in insulin-treated women (16.4±10.2%) as compared to the control subjects (8.7±2.5%). The diet-treated women had only 40% as many and those treated with insulin had more than twice as many receptors compared to control subjects on a per mg protein basis and if expressed per total placenta. In patients with overt diabetes mellitus maximum specific binding (18.5±10.6 %) was higher (p<0.05) due to more receptors compared to control subjects but was similar to the insulin-treated gestational diabetic patients. Maximum specific binding and receptor concentrations did not correlate linearly with maternal plasma insulin levels. Receptor affinities were virtually similar in all groups (1.8·109 l/mol). The placental glycogen content was reduced (p<0.05) to about 80% of that of control subjects in the diet-treated collective, whereas it was unchanged compared to control subjects in the insulin-treated gestational diabetic women despite a 40% increase (p<0.001) of the maternal-to-cord serum glucose ratio. In overt diabetic patients the maternal-to-cord serum glucose ratio and the placental glycogen content were higher (p<0.05) than in the control subjects. We conclude that trophoblast plasma membranes from gestational diabetic women treated with diet alone express less and those from women treated with insulin express more insulin receptors than those from a healthy control group in vitro. These differences could not have been disclosed without consideration of the mode of treatment. Trophoblast plasma membranes from overt diabetic women have more insulin receptors than those from healthy control subjects. 相似文献
77.
Patrick P. A. Humphrey Gary Buell Ian Kennedy Baljit S. Khakh Anton D. Michel Annmarie Surprenant Derek J. Trezise 《Naunyn-Schmiedeberg's archives of pharmacology》1995,352(6):585-596
Significant advances in understanding of P2X purinoceptor pharmacology have been made in the last few years. The limitations of nucleotide agonists as drug tools have now been amply demonstrated. Fortunately, inhibitors of the degrading ecto-ATPase enzymes are becoming available and it has become apparent that the complete removal of all divalent cations can be used experimentally in some systems to prevent nucleotide breakdown. Despite these issues, convincing evidence for P2X receptor heterogeneity, from data with agonists, has recently been reported.A number of new antagonists at P2X purinoceptors have also recently been described which to some degree appear to be more specific and useful than earlier antagonists like suramin. It is now apparent that suramin is a poor antagonist of ATP in many tissues because it potently inhibits ATPase activity at similar concentrations to those at which it blocks the P2X purinoceptor.Advances in the use of radiolabelled nucleotides as radioligands for binding studies has allowed the demonstration of P2X purinoceptors in a variety of tissues throughout the body including the brain. These studies have also provided evidence for receptor heterogeneity. Excitingly, two P2X purinoceptor genes have been cloned but operational studies suggest that more than two types exist. The cloning studies have also demonstrated a unique structure for the P2X purinoceptor which differentiates it from all other ligand-gated ion channel receptors. Further studies on P2X purinoceptor operation and structure are needed to help resolve controversies alluded to regarding the characterization and classification of nucleotide receptors. Hopefully such studies will also lead to a better understanding of the physiological and pathological importance of ATP and its activation of P2X purinoceptors. This will require the identification of better drug tools, in particular antagonists which may also provide the basis for novel therapeutic agents. 相似文献
78.
Soluble CD14 but not interleukin-6 is a new marker for clinical activity in atopic dermatitis 总被引:4,自引:0,他引:4
Summary Levels of soluble IL-2 receptors, IL-6, soluble CD23, soluble CD14 and ECP (eosinophilic cationic protein) were measured as markers of T-cell, B-cell, monocyte and eosinophilic leucocyte activation in 26 patients with atopic dermatitis (AD) on admission to (A) and at discharge from (D) the Department of Dermatology in Zurich. The serum levels of sIL-2R, IL-6, sCD23, sCD14 and ECP were significantly elevated in AD patients in comparison with the normal values of healthy donors. A significant decrease in sIL-2R (p=0.0093) and in sCD14 (p=0.0134) levels was demonstrated between A and D, correlating with the improvement in the skin intensity score (SIS). In addition, a significant correlation of the sCD14 levels and the SIS at A was demonstrated (p=0.0415). These results also incriminate monocytes in the pathogenesis of AD, indicating that, besides sIL-2R and ECP, SCD14 could also be a possible marker for the disease activity. 相似文献
79.
Neurophysiological investigation of effects of the D-1 agonist SKF 38393 on tonic activity of substantia nigra dopamine neurons 总被引:1,自引:0,他引:1
The effects of the D-1 agonist SKF 38393 on tonic activity of rat substantia nigra pars compacta dopamine neurons were studied using extracellular, single-unit recording techniques. Unlike nonselective D-1/D-2 dopamine agonists or the D-2 agonist quinpirole, SKF 38393 did not inhibit dopamine neuronal activity when applied iontophoretically or when administered intravenously in doses up to 20 mg/kg to chloral hydrate-anesthetized rats. Moreover, pretreatment with SKF 38393 did not alter the inhibitory response of these neurons to apomorphine or the D-2 agonist quinpirole. However, in locally anesthetized, gallamine-treated, artificially respired rats, dopamine cell activity was significantly altered by i.v. administration of SKF 38393; firing rate increases and decreases were observed. Administration of the inactive enantiomer of SKF 38393, S-SKF 38393, did not induce similar changes in parallel experiments. These results support the idea that unlike D-2 autoreceptor stimulation, D-1 receptor stimulation does not exert a direct local effect on dopamine neurons in the substantia nigra pars compacta and suggest that D-1 receptor stimulation at sites postsynaptic to the dopamine cells may indirectly affect the activity of some dopamine neurons through long-loop feedback mechanisms. 相似文献