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21.
Walter Balduini Gabriella Lombardelli Guidubaldo Peruzzi Flaminio Cattabeni 《Neurochemical research》1995,20(10):1211-1216
Carbachol-, norepinephrine- and glutamate-stimulated phosphoinositide metabolism was investigated in the neonatal, young and adult cerebral cortex slices of rats prenatally treated with methylazoxymethanol (MAM) on gestational day 15 (GD15) or GD19. In rat offspring treated on GD15 there was a significant reduction in the accumulation of [3H]inositol phosphates induced by carbachol and a significant increase in the accumulation of [3H]inositol phosphates induced by norepinephrine on day 7, whereas no changes were observed at the other ages. No significant changes, on the other hand, were observed for glutamate-stimulated phosphoinositide metabolism in GD15 treated rats and for carbachol-, norepinephrine- and glutamate-stimulated phosphoinositide metabolism in animals treated on GD19 at any of the different ages evaluated. These results indicate that treatment with MAM on GD15, which results in a marked microencephaly, causes a marked alteration of muscarinic and 1-adrenergic receptor-stimulated phosphoinositide metabolism during brain development and that these alterations undergo adaptive changes in the adult brain. 相似文献
22.
Horse serum Cholinesterase hydrolyzes choline and p-nitrophenol esters at different rates. Deacylation and acylation seem to be the rate-limiting step for charged and uncharged substrates respectively. Activation energy is similar for the acetic, propionic, and butyric esters of thiocholine, but it is higher for p-nitrophenylpropionate. Inhibition by the tetramethyl-ammonium ion is competitive. Tetraethyl-, tetrapropyl-, and tetrabutyl-ammonium ions are mixed-type inhibitors. The pH studies demonstrated the existence of a residue, pK = 6.33, involved in catalysis. 相似文献
23.
In this paper we study a method for the identification of the unknown parameter of the periodic function and also the first component of the state vector, in a mathematical model which describes the evolution of some diseases with an oro-fecal transmission.To solve the identification problem we use a numerical method to integrate the differential equations system, which reproduces the stability properties of the above mentioned continuous system.The numerical methods which we propose can be applied also to a spatial semi discretization of the reaction-diffusion model which is a diffusive generalization of the system that we consider in this paper.Finally, through an analysis on both the continuous and the discrete system we also obtain a necessary condition on the experimental data in order that a periodic trajectory of the system exists.Work supported by: Progetto Finalizzato Controllo Malattie da Infezione-CNR and by Ministero Pubblica Istruzione 相似文献
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25.
Biochemical changes of rat brain membranes with aging 总被引:4,自引:0,他引:4
Gabriella Calderini Anna Chiara Bonetti Antonio Battistella Fulton Timm Crews Gino Toffano 《Neurochemical research》1983,8(4):483-492
Modification of membrane composition and enzymatic activities both in total brain homogenate and purified synaptic plasma membrane of 3 and 24 month old rats has been investigated. Protein, cholesterol and phospholipid content and (Na+, K+)ATPase and 2',3' cyclic nucleotide phosphohydrolase activities were determined. The major changes occurred in the whole homogenate where a general increase in total protein and cholesterol content with age and a significant increase of the cholesterol/phospholipids molar ratio has been detected. In S.P.M. aging process induced a decrease of protein, cholesterol and phospholipids content associated with an increased membrane viscosity and a decrease of delta E. These data are consistent with a change in the structural organization and in the distribution pattern of different cell population in the aging brain. A possible artifactual effect of freezing on the reported parameter is also discussed. 相似文献
26.
Cartesio Favalli Peter Leport Bernard M. Jaffe M.Gabriella Santoro Thomas Simmet Vera Del Gobbo Enrico Garaci 《Cellular immunology》1982,72(2):351-359
The effect of 16,16-dimethyl-PGE2-methyl ester (di-M-PGE2) on humoral and cellular immunoresponsiveness has been compared in normal mice and in mice immunosuppressed by splenectomy and thymectomy plus antithymocyte serum (ATS). Splenectomy resulted in immunosuppression manifested by augmentation of B-16 melanoma growth; this stimulatory effect was reversed by di-M-PGE2. In animals immunosuppressed by thymectomy plus ATS, di-M-PGE2 augmented the humoral and cellular immune responses; this was manifested by slowing of the growth of B-16 melanoma and by stimulating the number of plaque-forming cells, hemagglutinin titers, and delayed-hypersensitivity reactions to sheep erythrocytes. In contrast, in normal (nonthymectomized) mice, di-M-PGE2 was mildly immunosuppressive. Finally, adriamycin-immunosuppressed normal mice and this suppression were reversed by the addition of di-M-PGE2 to the treatment regimen. 相似文献
27.
Further observations relating sex size ratios to mating success in calanoid copepods 总被引:2,自引:0,他引:2
Mating experiments using 153 pairs of Diaptomus leptopus Forbeswere video-taped in the laboratory. The following were measuredand scored: attempted capture of the female by the male, timeto successful capture and mounting, duration of copulation,spermatophore placement, time to clutch extrusion, prosome lengthsof all individuals and sex size ratios (female:male lengths)of all pairs. Mating success was not a function of sex sizeratio for D.leptopus at ratios commonly observed in nature inthe populations tested. However, this lack of relationship maynot be true of all populations. Photographic analysis of D.leptopusas well as D.birgei Marsh showed that males always held ontofemale genital segments in the vicinity of the spines with theirright fifth legs. Pearson correlations were calculated comparingprosome lengths to a variety of genital parts. The strongestrelationships were found with female genital segment width atthe level of the spines for both species, and male right fifthleg claw length for D.birgei. These data support the hypothesisthat the relationship between sex size ratio and mating successmay be species specific. 相似文献
28.
29.
Abstract The genus Allium L. in Italy. IV. A DNA cytophotometric study on the pollen grain of Allium chamaemoly L. — A cytophotometric analysis of DNA contents in pollen generative and vegetative nuclei of Allium chamaemoly L. was carried out. DNA synthesis in both nuclei was confirmed and a lightly higher DNA amount than 2C in the vegetative nucleus was pointed out. An analysis of the Fast-green stainable histones in the generative and vegetative nuclei was also accomplished. While the generative nucleus had a very high content of Fast-green stainable histone, the vegetative one have nearly no stainable histone. The occurrence of DNA synthesis and the very low histone content suggest the vegetative nucleus is functional and biochemically activ. The higher than 2C DNA content supports the possibility of a DNA amplification process including probably the amplification of ribosomal cistrons in the pollen vegetative nucleus. 相似文献
30.
Widely used for mapping afferent activated brain areas in vivo, the label-free intrinsic optical signal (IOS) is mainly ascribed to blood volume changes subsequent to glial glutamate uptake. By contrast, IOS imaged in vitro is generally attributed to neuronal and glial cell swelling, however the relative contribution of different cell types and molecular players remained largely unknown. We characterized IOS to Schaffer collateral stimulation in the rat hippocampal slice using a 464-element photodiode-array device that enables IOS monitoring at 0.6 ms time-resolution in combination with simultaneous field potential recordings. We used brief half-maximal stimuli by applying a medium intensity 50 Volt-stimulus train within 50 ms (20 Hz). IOS was primarily observed in the str. pyramidale and proximal region of the str. radiatum of the hippocampus. It was eliminated by tetrodotoxin blockade of voltage-gated Na+ channels and was significantly enhanced by suppressing inhibitory signaling with gamma-aminobutyric acid(A) receptor antagonist picrotoxin. We found that IOS was predominantly initiated by postsynaptic Glu receptor activation and progressed by the activation of astroglial Glu transporters and Mg2+-independent astroglial N-methyl-D-aspartate receptors. Under control conditions, role for neuronal K+/Cl− cotransporter KCC2, but not for glial Na+/K+/Cl− cotransporter NKCC1 was observed. Slight enhancement and inhibition of IOS through non-specific Cl− and volume-regulated anion channels, respectively, were also depicted. High-frequency IOS imaging, evoked by brief afferent stimulation in brain slices provide a new paradigm for studying mechanisms underlying IOS genesis. Major players disclosed this way imply that spatiotemporal IOS reflects glutamatergic neuronal activation and astroglial response, as observed within the hippocampus. Our model may help to better interpret in vivo IOS and support diagnosis in the future. 相似文献