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991.
Anode Break Excitation in Space-Clamped Squid Axons 总被引:1,自引:0,他引:1
Strength-duration curves for space-clamped squid axons, using square wave anode breaks as stimuli, established the existence of four distinct regions. For the average experimental axon the intersection of the first two regions, τ1, occurs at about 7 msec. This agrees with computations based on the Hodgkin-Huxley (HH) equations and corresponds to the accommodation time constant found previously for a linearly rising ramp, as given by the HH equations and as found experimentally. The second break in the curve, τ2, at about 200 msec, and the third break, τ3, at 1 sec, are far beyond the range of the HH equations and may be the counterpart in the excitability of the long time constants, which have been apparent from a number of other types of experiments. The regions of the curve before 1 msec and beyond 2 or 3 sec are quite variable and may represent breakdown. Rheobase increases in both experimental and computed axons when temperature is raised. In both experimental and computed axons τ1 descreases slightly when the temperature is raised from 10 to 15°C. At 20 and 25°C, τ1 of the experimental axon increases markedly. 相似文献
992.
993.
Francesca Brescia Maurizio Sarti Rita Massa Maria L. Calabrese Anna Sannino Maria R. Scarfì 《Bioelectromagnetics》2009,30(7):525
This study was designed to assess if radiofrequency (RF) radiation induces oxidative stress in cultured mammalian cells when given alone or in combination with ferrous ions (FeSO4). For this purpose the production of reactive oxygen species (ROS) was measured by flow cytometry in human lymphoblastoid cells exposed to 1950 MHz signal used by the third generation wireless technology of the Universal Mobile Telecommunication System (UMTS) at Specific Absorption Rate of 0.5 and 2.0 W/kg. Short (5–60 min) or long (24 h) duration exposures were carried out in a waveguide system under strictly controlled conditions of both dosimetry and environment. Cell viability was also measured after 24 h RF exposure using the Resazurin and Neutral Red assays. Several co‐exposure protocols were applied to test if RF radiation is able to alter ROS formation induced by FeSO4 (RF given before or concurrently to FeSO4). The results obtained indicate that non‐thermal RF exposures do not increase spontaneous ROS formation in any of the experimental conditions investigated. Consistent with the lack of ROS production, no change in cell viability was observed in Jurkat cells exposed to RF radiation for 24 h. Similar results were obtained when co‐exposures were considered: combined exposures to RF radiation and FeSO4 did not increase ROS formation induced by the chemical treatment alone. In contrast, in cultures treated with FeSO4 as positive control, a dose‐dependent increase in ROS formation was recorded, validating the sensitivity of the method employed. Bioelectromagnetics 30:525–535, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
994.
995.
Andreoli V Nicoletti G Romeo N Condino F La Russa A Liguori M Manna I Spadafora P Quattrone A Cittadella R 《Neurochemical research》2007,32(9):1445-1449
Tumor Necrosis Factor Receptor Super Family 6 gene (TNFRSF6), also known as FAS, encodes the Fas antigen, a cell surface receptor
mediating cell apoptosis, situated on chromosome 10q located near the region of linkage to sporadic Alzheimer’s disease (sAD).
FAS levels have been reported elevated in the brain of AD patients. Due to both positional and pathobiological criteria, the
association of the FAS antigen with this pathology is of great interest. We have tested two SNPs in the FAS gene in 223 Italian
patients with non-familial AD from Southern Italy (Calabria region) and 211 healthy control subjects. No significant differences
in allelic and genotypic distributions were found between cases and controls, or late and early-onset AD patients, thus suggesting
that these polymorphisms do not represent an AD risk factor in our population. 相似文献
996.
Sheng JR Jagodic M Dahlman I Becanovic K Nohra R Marta M Iacobaeus E Olsson T Wallström E 《Genetics》2005,170(1):283-289
Multiple sclerosis (MS) and its animal model, myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis (MOG-EAE), share a complex genetic predisposition with contributions from the major histocompatibility complex class II genes and many other genes. Linkage mapping in F(2) crosses between the susceptible DA rat strain and the resistant ACI or BN rat strains in various models of autoimmune neuroinflammation have repeatedly displayed suggestive linkage to a region on rat chromosome 15. A direct study of this region was undertaken in congenic strains by transferring resistant ACI alleles to the susceptible DA background. Phenotypic analysis demonstrated lower maximal and cumulative EAE scores in the DA.ACI-D15Rat6-D15Rat71 (C15), DA.ACI-D15Rat6-D15Rat48, D15Rat126-D15Rat71 (C15R3b), and DA.ACI-D15Rat23-D15rat71 (C15R4) strains compared to the parental DA rat strain. Linkage analysis was then performed in a (DA x PVG.AV1)F(7) advanced intercross line, resulting in a LOD score of 4.7 for the maximal EAE score phenotype at the peak marker D15Rat71 and a confidence interval of 13 Mb, overlapping with the congenic fragment defined by the C15R3b and the C15R4 strains. Thus, a new MOG-EAE locus with the designation Eae19 is identified on rat chromosome 15. There are 32 confirmed or predicted genes in the confidence interval, including immune-responsive gene 1 and neuronal ceroid lipofuscinose gene 5. Definition of loci such as Eae19 enables the characterization of genetically regulated, evolutionary conserved disease pathways in complex neuroinflammatory diseases. 相似文献
997.
998.
999.
Christina B. Karsten Falk F. R. Buettner Samanta Cajic Inga Nehlmeier Berit Neumann Antonina Klippert Ulrike Sauermann Udo Reichl Rita Gerardy-Schahn Erdmann Rapp Christiane Stahl-Hennig Stefan P?hlmann 《Journal of virology》2015,89(22):11727-11733
Human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) envelope (Env) proteins are extensively decorated with N-glycans, predominantly of the high-mannose type. However, it is unclear how high-mannose N-glycans on Env impact viral spread. We show that exclusive modification of SIV Env with these N-glycans reduces viral infectivity and abrogates mucosal transmission, despite increasing viral capture by immune cell lectins. Thus, high-mannose N-glycans have opposed effects on SIV infectivity and lectin reactivity, and a balance might be required for efficient mucosal transmission. 相似文献
1000.
Salamon Andras Maszlag-Török Rita Veres Gábor Boros Fanni Annamária Vágvölgyi-Sümegi Evelin Somogyi Anett Vécsei László Klivényi Péter Zádori Dénes 《Neurochemical research》2020,45(9):2072-2081
Neurochemical Research - The potential role of Sirt1 and Sirt2 subtypes of Sirtuins (class III NAD+-dependent deacetylases) in the pathogenesis of Huntington’s disease (HD) has been... 相似文献