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1.
Epidermal growth factor (EGF) has been considered to be a candidate for neurotrophic factors on the basis of the results of several in vitro studies. However, the in vivo effect of EGF on ischemic neurons as well as its mechanism of action have not been fully understood. In the present in vivo study using a gerbil ischemia-model, we examined the effects of EGF on ischemia-induced learning disability and hippocampal CA1 neuron damage. Cerebroventricular infusion of EGF (24 or 120 ng/d) for 7 days to gerbils starting 2 hours before or immediately after transient forebrain ischemia caused a significant prolongation of response latency time in a passive avoidance task in comparison with the response latency of vehicle-treated ischemic animals. Subsequent histologic examinations showed that EGF effectively prevented delayed neuronal death of CA1 neurons in the stratum pyramidale and preserved synapses intact within the strata moleculare, radiatum, and oriens of the hippocampal CA1 region. In situ detection of DNA fragmentation (TUNEL staining) revealed that ischemic animals infused with EGF contained fewer TUNEL-positive neurons in the hippocampal CA1 field than those infused with vehicle alone at the seventh day after ischemia. In primary hippocampal cultures, EGF (0.048 to 6.0 ng/mL) extended the survival of cultured neurons, facilitated neurite outgrowth, and prevented neuronal damage caused by the hydroxyl radical-producing agent FeSO4 and by the peroxynitrite-producing agent 3-morpholinosydnonimine in a dose-dependent manner. Moreover, EGF significantly attenuated FeSO4-induced lipid peroxidation of cultured neurons. These findings suggest that EGF has a neuroprotective effect on ischemic hippocampal neurons in vivo possibly through inhibition of free radical neurotoxicity and lipid peroxidation.  相似文献   
2.
For the purpose of modelling the impact of carbon on radiation damage phenomena in steels, we have performed an extensive set of first principle calculations on the Fe-Cr-C system. The calculated solution and diffusion enthalpies of carbon in iron and in chromium agree well with experimental data, as do the relative formation energies of mono-carbides, cementite, Hägg and M23C6 carbides. Our data further indicate that interstitial carbon is attracted to a solute iron atom in bcc chromium, while the reaction between carbon and a solute chromium atom in bcc iron is repulsive. An empirical potential fitted to data for iron carbides is capable of reproducing melting behaviour of cementite, while the predicted interaction with point defects agrees less well with DFT data than a potential recently published by Hepburn and Ackland.  相似文献   
3.
In project-based industries studies show difficulties in extracting, distributing and applying embedded and practice knowledge across structural and organisational boundaries. We focus on interorganisational projects consisting of distributed and embedded knowledge. Interaction becomes important in order to cooperate and share interorganisational and distributed knowledge. The aim of the research is to explore how sharing and generating practice based and distributed knowledge occurs through interaction in interorganisational projects and how this is managed. The study focuses on the design phase and relates traditional design practices to concurrent design practices. In the study we observed six cases of design meetings in the construction and oil and gas industry and performed 31 interviews. The paper contributes with the following: (1) understanding and visualisation of interaction patterns, (2) insight in use of various forms of interaction, and (3) ways of managing distributed and embedded knowledge through interaction.  相似文献   
4.
Although people often have to learn from environments with scarce and highly selective outcome feedback, the question of how nonfeedback trials are represented in memory and affect later performance has received little attention in models of learning and decision making. In this article, the authors use the generalized context model (Nosofsky, 1986) as a vehicle to test contrasting hypotheses about the coding of nonfeedback trials. Data across 3 experiments with selective decision-contingent and selective outcome-contingent feedback provide support for the hypothesis of constructivist coding (Elwin, Juslin, Olsson, & Enkvist, 2007), according to which the outcomes on nonfeedback trials are coded with the most likely outcome, as inferred by the individual. The relation to sampling-based approaches to judgment, and the adaptive significance of constructivist coding, are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
The characteristics of male adolescent suicide victims with (n = 84) and without (n = 8) a diagnosable psychiatric disorder were compared. Using psychological autopsy methods--interviews with victims' family members and health care professionals, and review of records (e.g., medical, school, police)-data were collected on all adolescent suicides in Finland during a 12-month period. Compared with adolescents with a psychiatric disorder, those with no disorder tended to come from less disturbed families, had shown less antisocial behavior, and had less frequently utilized health care and social services. Adolescents with no disorder more often communicated suicidal thoughts for the first time just before the suicide, and difficulties with the law (discipline problems) were more common precipitants than among those with a disorder. It was concluded that the process leading to suicide seems to be relatively short among male adolescents with no diagnosable psychiatric disorder. Communication of suicidal intent and problems with discipline are among the few clinical warning signs.  相似文献   
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7.
Completed and attempted suicide are major public health problems in most western countries. The importance of suicidal behavior as a health problem, particularly among adolescents and young adults, has been emphasized by the European Union, the WHO (Europe), as well as the Finnish authorities. Due to the exceptionally high suicide mortality, suicide prevention has been one of the main targets of Finnish health policy since the late 1980s. However, to develop feasible strategies for suicide prevention, better knowledge of the phenomenon of self-destruction is necessary. The Department of Mental Health of the National Public Health Institute has been actively involved in suicide research and the development of suicide strategies both in Finland and western Europe since 1986. The success is based on a long tradition of suicide research in Finland, the representative and reliable suicide data, a highly motivated research group, and also the necessary economic support by both the National Public Health Institute and the Finnish Academy. This article outlines our groups research plan for the next few years.  相似文献   
8.
A syngeneic, androgen-sensitive Dunning R3327 rat prostatic adenocarcinoma was transplanted bilaterally in the flanks of male Copenhagen Fisher rats. Approximately 3 months after implantation, when the tumours had a median volume of 150 mm3, one group of rats was treated with histamine alone (4 mg kg(-1) subcutaneously on week days), another group with human recombinant interleukin 2 (IL-2) alone (425 IU kg(-1) continuous infusion) and a third group with both histamine and IL-2 during 6 weeks. Tumours on one flank were irradiated (6 Gy once daily for 3 days to a total dose of 18 Gy) beginning 1 week after the onset of treatment with histamine and/or IL-2. The contralateral tumour served as the intra-animal control. The tumour volumes were determined weekly. The growth curves showed that all three drug treatments were effective in delaying growth, but when used individually did not cause tumour shrinkage. Radiation was the most effective single agent, but when used alone the shrinkage did not occur until 2 weeks after irradiation. When combined with the drugs, more rapid and extensive growth delay and/or shrinkage was seen. The growth curves showed clear differences between the different treatments. The combination of the three agents was the most effective of all. The most striking difference between radiation alone and radiation plus biotherapy was the time at which a tumour response was detectable. Thus, active biotherapy alone and especially in a combination with histamine and radiotherapy warrants further investigation as a potential therapeutic approach to prostate cancer.  相似文献   
9.
Idiotypic structures expressed on the myeloma Ig protein might be regarded as a tumor-specific antigen. Five patients with IgG myeloma were immunized with the purified serum M-component by repeated intradermal injections together with soluble granulocyte-macrophage colony-stimulating factor (GM-CSF). All patients developed an idiotype (Id)-specific T-cell immunity, defined as blood T cells predominantly secreting interferon-gamma (IFN-gamma) and interleukin-2 (IL-2) (type I cells). Id-specific DNA synthesis was induced in one patient. Delayed-type hypersensitivity against the Id was not evoked. The specific IFN-gamma/IL-2 T-cell response was inhibited (46% to 100%) by a major histocompatibility complex (MHC) class I monoclonal antibody (MoAb) in all five patients. A 5% to 37% inhibition by an MHC class II MoAb was seen in four patients. CD4+ as well as CD8+ T cells enriched by magnetic microbeads contained Id-specific cells. The T cells recognized peptides corresponding to the complementarity-determining regions 1, 2, and 3 of the heavy chain of the Id. There was a transient rise of B cells producing IgM anti-idiotypic antibodies in all patients. The results indicate that immunization of myeloma patients using the autologous M-component and soluble GM-CSF may evoke an Id-specific predominantly MHC class I-restricted type I T-cell response.  相似文献   
10.
Homozygous protein C deficiency (HPCD) with purpura fulminans is a rare condition with an estimated incidence of 1-2 per 400,000 births. About 20 case reports have appeared since the first one was published in 1983. HPCD provides an excellent illustration of the fundamental importance of the protein C anticoagulant pathway. This severe coagulopathy results in serious organ damage, often already in utero, and without treatment it is incompatible with life. The treatment options include fresh frozen plasma and protein C concentrate in the acute phase, followed by oral anticoagulant therapy. Over 160 different point mutations in the protein C gene have been identified in recent years, offering new possibilities for prenatal diagnosis. The article describes the case of a family who lost two children with congenital HPCD. But where the specific point mutation was identified thus enabling prenatal diagnosis to be performed in a subsequent pregnancy.  相似文献   
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