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991.
During storage of whole blood samples the results of white blood cell counts on a Sysmex NE-8000 Hematology Analyser showed an apparent shift from the granulocytes towards monocytes. The effects of various storage conditions were investigated by incubating blood samples at different temperatures and time intervals. Granulocyte activation and degranulation during storage resulted in a false elevation of the automated monocyte differential counts. The phenomenon occurs at temperatures beyond ambient room temperature. 相似文献
992.
P. H. Ghatan M. Ingvar L. Eriksson S. Stone-Elander M. Serrander K. Ekberg J. Wahren 《Psychopharmacology》1998,136(2):179-189
For the smoker, nicotine has a positive effect on attention, cognition and mood. Conversely, nicotine abstinence is characterized
by uncomfortable psychological effects such as impaired attention, but also irritability. We postulated that nicotine exerts
an effect on cerebral areas important for attention and mood. Regional cerebral blood flow (rCBF), as an index for cerebral
activity, was measured in both smokers and non-smokers. They were scanned during performance of a psychometric task with and
without IV infusion of nicotine (1-methyl-2-[3-pyridyl1] pyrrolidine). Nicotine induced rCBF decreases in the anterior cingulate
cortex and the cerebellum, and concomitant increases in the occipital cortex. The changes were similar in nature and magnitude
in smokers and non-smokers. Thus, specific changes were induced in areas pertaining to the anterior attention system and to
higher order visual cortex. We conclude that these effects on cerebral activity provide insights into the desired positive
effects of nicotine on cognition as well as the negative effects experienced during nicotine abstinence.
Received: 9 June 1997/Final version: 8 September 1997 相似文献
993.
Summary. The binding of acrosome reacted mammalian sperm to the egg plasma membrane initiates a series of signaling events in the egg, termed "egg activation", which lead to the completion of meiosis II and the initiation of a mitotic cell cycle. Many of these signaling events have characteristics of classical signal transduction events in somatic cells. Currently, there are two hypotheses for how sperm-induced egg activation is initiated. In the "receptor" hypothesis, the fertilizing sperm interacts with a specific egg surface receptor, and this interaction leads to signal transduction and effector activation. In the "fusion" hypothesis it is postulated that following fusion of the sperm and egg plasma membranes a soluble sperm-derived factor enters the egg's cytoplasm and activates pathways leading to egg activation. This chapter will provide an overview of the processes of cell–cell interaction and signal transduction leading to mammalian egg activation. It will concentrate on specific molecules proposed to be involved in sperm-egg interaction, signal transduction and effector mechanisms involved in egg activation, and a discussion of sperm-associated factors that have been implicated in egg activation. 相似文献
994.
Hashimoto Naofumi Ichihashi Teruhisa Yamamoto Etsuko Hirano Koichiro Inoue Masayoshi Tanaka Hiroyoshi Yamada Hideo 《Pharmaceutical research》1988,5(5):266-271
The epimerization rate constants of R- and S-epimers of moxalactam (LMOX) in a frozen aqueous solution decreased as the temperature decreased. The reaction proceeded in the unfrozen region remaining in the frozen solution, without being affected by the ice. The reaction stopped completely below the collapse temperature of the LMOX aqueous solution. The ratio of R- and S-epimers at equilibrium, which was equal to the ratio of the epimerization rate constant, increased as the temperature decreased. This change in the ratio at equilibrium could be ascribed to the difference in the activation energy between the two epimers. 相似文献
995.
《Nutrition reviews》1984,42(8):281-283
Preterm infants fed their mothers' milk showed equivalent growth and superior energy retention to a similar cohort of infants fed formula. 相似文献
996.
H. Yokozeki Kaoru Takayama Olina Ohki Takahiro Satoh Tadashi Umeda Ichiro Katayama Kiyoshi Nishioka 《Archives of dermatological research》1998,290(10):547-552
Abstract Although both CD80 (B7–1) and CD86 (B7–2/B70) have been recently identified in cultured human Langerhans cells (LC), little
is known of the role and regulatory properties of CD80 and CD86 on human LC. We present here the results of a study comparing
the expression and function of CD80 and CD86 in human LC using the T-helper type-1 cytokines IL-2 and interferon γ (IFN)-γ, and the T-helper type-2 cytokines IL-10, IL-4 and granulocyte/macrophage colony-stimulating factor (GM-CSF). Freshly isolated
human LC expressed little CD80 and CD86 in vitro, but the expression of both molecules was rapidly induced during a 72-h incubation
with cytokines and the expression of CD86 occurred much earlier and more strongly than that of CD80. The expression of both
CD80 and CD86 was upregulated by GM-CSF and downregulated by IL-10, and the expression of CD86, but not that of CD80, was
upregulated by both IL-4 and IFN-γ. Finally, pretreatment of LC with GM-CSF and IFN-γ, but not with IL-4, enhanced the alloreactive T-cell proliferation induced by the LC, and IL-10 pretreatment of LC decreased
their capacity for alloreaction. These results indicate that the expression of both CD80 and CD86 on human LC may be regulated
by these cytokines (IL-2, IL-4, GM-CSF, IFN-γ and IL-10) secreted from helper T cells infiltrating into the inflammatory microenvironment.
Received: 4 December 1997 相似文献
997.
《Nutrition reviews》1980,38(10):337-338
Marked variations in basal metabolic rate and mechanical work efficiency of individuals on high and low energy intakes suggest adaptation to low energy intakes. 相似文献
998.
Michael C. Klein Jennifer J. Poulakos Sheldon B. Gertner Allan Siegel 《Drug development research》1983,3(6):581-587
Homodimaprit (SKF-91488) when injected into the lateral ventricle of the rat resulted in a delayed behavioral syndrome characterized by motor incoordination, hyperexcitability, and aggressive behavior, which occurred 18 hr after injection and ultimately caused death 24–72 hr after injection. In order to determine where the neural effects were occurring, the [14C]2-deoxyglucose technique was utilized to identify possible sites of brain neural activation. Histological examination revealed that homodimaprit produced periventricular lesions at 18 hr. Autoradiographic analysis demonstrated increased ipsilateral activation in the nucleus accumbens, lateral septal nucleus, bed nucleus of the stria terminalis, caudato-putamen, and the rostral half of the dorsal hippocampus. Bilateral activation was observed in the medial preoptico-hypothalamus, midline thalamic nuclei including the mediodorsal nucleus, and the periventricular central gray. These findings suggest that the delayed behavioral effects of homodimaprit are probably the result of the activation of these specific areas of the brain and the resulting periventricular lesions. The mechanism by which homodimaprit produces these effects, however, remains unknown. 相似文献
999.
1000.
Michael J. Prival Valerie D. King Albert T. Sheldon 《Environmental and molecular mutagenesis》1979,1(2):95-104
N-nitrosodimethylamine (DMN) is not mutagenic in the standard Salmonella plate incorporation assay (Ames test) in the presence of an in vitro metabolic activation system (S-9) derived from rat liver. When the S-9 was derived from Aroclor- or phenobarbital-induced mouse or hamster liver or from uninduced hamster liver, mutagenic activity was observed. Increasing the amount of S-9 above the usual maximum level of 50 μ1 per plate increased the mutagenic response. Similarly, the mutagenicity of N-nitrosodiethylamine (DEN) and N-nitrosodi(n-butyl)amine (DBN) was greater in the presence of hamster liver S-9 than when mouse or rat liver was used. Data are also presented indicating that the ability of rat liver S-9 to mediate the mutagenic activity of DMN in the “preincubation” assay is due to the fact that the various components are present in this assay at several times the concentrations attained in the standard plate incorporation assay. 相似文献