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1.
Chronic constriction injury (CCI) of the rat sciatic nerve increases the dorsal horn excitability. This “central sensitization” leads to behavioral manifestations analogous to those related to human neuropathic pain. We found, using whole-cell recording from acutely isolated spinal cord slices, that 7-to 10-day-long CCI increases excitatory synaptic drive to putative excitatory “delay”-firing neurons in the substantia gelatinosa but attenuates that to putative inhibitory “tonic”-firing neurons. A defined-medium organotypic culture (DMOTC) system was used to investigate the long-term actions of brain-derived neurotrophic factor (BDNF) as a possible instigator of these changes. When all five neuronal types found in the substantia gelatinosa were considered, BDNF and CCI produced similar patterns, or “footprints,” of changes across the whole population. This pattern was not seen with another putative “pain mediator,” interleukin 1β. Thus, BDNF decreased synaptic drive to “tonic” neurons and increased synaptic drive to “delay” neurons. Actions of BDNF on “delay” neurons were presynaptic and involved increased mEPSC frequency and amplitude without changes in the function of postsynaptic AMPA receptors. By contrast, BDNF exerted both pre-and post-synaptic actions on “ tonic” cells to reduce the mEPSC frequency and amplitude. These differential actions of BDNF on excitatory and inhibitory neurons contributed to a global increase in the dorsal horn network excitability as assessed by the amplitude of depolarization-induced increases in the intracellular [Ca2+]. Experiments with the BDNF-binding protein TrkB-d5 provided additional evidence for BDNF as a harbinger of neuropathic pain. Thus, the cellular processes altered by BDNF likely contribute to “central sensitization” and hence to the onset of neuropathic pain. Neirofiziologiya/Neurophysiology, Vol. 39, Nos. 4/5, pp. 315–326, July–October, 2007.  相似文献   

2.
A mathematical model (Kliemann, W. 1987.Bull. math. Biol. 49, 135–152.) that predicts the quantitative branching pattern of dendritic tree was evaluated using the apical and basal dendrites of rat hippocampal neurons. The Wald statistics for χ2-test was developed for the branching pattern of dendritic trees and for the distribution of the maximal order of the tree. Using this statistic, we obtained a reasonable, but not excellent, fit of the mathematical model for the dendritic data. The model's predictability of branching patterns was greatly enhanced by replacing one of the assumptions used for the original model “splitting of branches for all dendritic orders is stochastically independent”, with a new assumption “branches are more likely to split in areas where there is already a high density of branches”. The modified model delivered an excellent fit for basal dendrites and for the apical dendrites of hippocampal neurons from young rats (30–34 days postpartum). This indicates that for these cells the development of dendritic patterns is the result of a purely random and a systematic component, where the latter one depends on the density of dendritic branches in the brain area considered. For apical dendrites there is a trend towards decreasing pattern predictability with increasing age. This appears to reflect the late arrival of afferents and subsequent synaptogenesis proximal on the apical dendritic tree of hippocampal neurons.  相似文献   

3.
Summary. Objectives. Human gliomas have a catastrophic prognosis with a median survival in the range of one year even after therapeutic treatment. Relatively high resistance towards apoptotic stimuli is the characteristic feature of malignant gliomas. Since cell cycle control has been shown to be the key mechanism controlling both apoptosis and proliferation, this study focuses on DNA damage analysis and protein expression patterns of essential cell cycle regulators P53 and P21waf1/cip1 in glioma under clinically relevant therapeutic conditions. Material and methods. U87MG cell line, characterised by wild p53-phenotype relevant for the majority of primary malignant glioblastomas, was used. Glioma cells underwent either irradiation or temozolomide treatment alone, or combined radio/chemo treatment. DNA damage was analysed by the “Comet Assay”. Expression rates of target proteins were analysed using “Western-Blot” technique. Results and conclusions. “Comet Assay” demonstrated extensive DNA damage caused by temozolomide treatment alone and in combination with irradiation, correlating well with the low survival rate observed under these treatment conditions. In contrast, irradiation alone resulted in a relatively low DNA damage, correlating well with a high survival rate and indicating a poor therapeutic efficiency of irradiation alone. Unusually low up-regulation of P53 and P21waf1/cip1 expression patterns was produced by the hereby tested stressful conditions. A deficit in cell cycle control might be the clue to the high resistance of malignant glioma cells to established therapeutic approaches.  相似文献   

4.
Summary Microvascular endothelial cells from bovine adrenal medulla and brain and macrovessel endothelial cells from bovine aorta were isolated and cultured under similar conditions in order to determine morphologic and biochemical heterogeneity in vitro. All three cell types exhibited nearly identical ultrastructural morphology and two-dimensional gel protein patterns of35S-methionine-labeled whole cells. Two-dimensional gel analysis of35S-methionine-labeled plasma membrane proteins however, revealed two-dimensional gel protein patterns unique to the tissue type from which the endothelial cells were isolated. This suggests that the functional significance of these specific endothelial cell types is manifested primarily in surface-associated proteins and that many of the differences are sustained in culture. To determine the potential of aorta, brain, and adrenal medulla endothelial cell (EC) cultures to respond to developmentally significant signals, morphology, growth pattern, and cell surface proteins were monitored in the presence and absence of growth factors. A 17 to 26% increase in cell density as well as an increase in the number of elongated and overlapping cells resulted when all three EC types were exposed to a mitogenic medium. Additionally, expression of specific glycoprotein profiles, as determined by Concanavalin A Western blotting of two-dimensional gels, was dependent on the presence or absence of growth factors in the medium. The ability to induce this morphologic and biochemical variation in the three endothelial cell types was maintained into later passage. Taken together, these data imply that endothelial cells isolated from different tissues exhibit and maintain biochemical heterogeneity and do not completely dedifferentiate into a common endothelial cell type in culture. Furthermore, expression of specific subsets of cell surface proteins is dependent on environmental conditions, and in some cases is both cell-type and media-type dependent. Thus, even though endothelial cells are considered terminally differentiated cells, there exists additional or “latent” heterogeneity in the ability of these different cells to respond to “developmental signals” (i.e. mitogenic medium) in vitro. This work was supported in part by a grant from the American Heart Association (860929), NIH (GM29127), and a Biomedical Research Grant from the University of Massachusetts.  相似文献   

5.
A lectin was isolated fromCanavalia brasiliensis Mart. seeds by combining solubility fractionation with affinity chromatography on Sephadex G-50. The lectin showed a carbohydrate specificity for D-mannose (D-glucose) binding and a requirement for Ca2+ and Mn2+. All the hemagglutinating activity was found in the cotyledons and the presence of the lectin was followed during the first 15 days of plant germination, through the activity against rabbit erythrocytes, the presence of the “lectin peak” in Sephadex G-50 affinity chromatography, presence of the “lectin bands” in SDS-polyacrylamide gel electrophoresis and the “lectin arcs and rockets” in immunoelectrophoresis in agarose gel. On application of all these methods the lectin showed a differentiated metabolism, disappearing more slowly than the other high molecular weight proteins of the seed.  相似文献   

6.
7.
Membranes from in vivo labeled cells of Rhodobacter capsulatus U43[pTX35] grown photosynthetically carried 60% of the [32P]-Pi in the “heavy” fraction (HM) after sucrose gradient sedimentation. Metal-chelating chromatography of either “heavy” or “light” (LM) membrane fractions rendered similar Bchl-protein complex profiles after octyl-glucoside treatment, including most of the radioactivity in the same corresponding elution fraction (F II). Similar labeling distribution of pigment-protein complexes was obtained for membranes of dark-grown cells induced by lowering oxygen tension. Fractions derived from HM showed highly labeled LHIα, whereas the same complex from LM was essentially [32P]-Pi-free, as revealed by SDS-PAGE followed by autoradiography. Phospholipid analysis showed a similar pattern for membranes isolated from cells photosynthetically or semiaerobically grown, being the most abundant: phosphatidylglycerol, phosphatidylethanolamine, cardiolipin, and phosphatidylcholine. Part of the phospholipids from HM comigrated with LHIα during SDS-PAGE and dissociated from the complexes only after solvent extraction and hydrophobic chromatography. However, a small amount remained always attached to LHIα, indicating an unusual strong interaction. These results suggest the existence of two operationally defined membrane regions carrying LHIα complexes differing in phosphorylation status and protein-phospholipid interaction. Received: 10 August 1996 / Accepted: 10 September 1996  相似文献   

8.
It is found that for a simple circuit of neurons, if this contains an odd number of inhibitory fibers, or none at all, or if the product of the activity parameters is less than unity, then the stimulus pattern always determines uniquely the steady-state activity. For circuits not of one of these types, it is possible to classify exclusively and exhaustively all possible activity patterns into three types, here called “odd”, “even”, and “mixed”. For any pattern of odd type and any pattern of even type there always exists a stimulus pattern consistent with both, but in no other way can such an association of activity patterns be made.  相似文献   

9.
The objective of this article is to study the effect of 5-aminolevulinic acid (ALA) and enhanced chlorophyll content, antioxidative enzymes and photosynthesis rate by foliar application of ALA. We evaluated three concentrations (control-distilled water, T1-50 mg l−1, T2-150 mg l−1, T3-250 mg l−1) of ALA and seven cultivars, “Sanchidaye” (Sa-1), “Lichuandasuomian” (Li-1), “Aijiaohuang” (Ai-1), “Qingyou” No. 4 (Qi-1), “Aikang” No. 5 (Ak-1), “Hanxiao” (Ha-1) and “Shulv” (Sl-1). “Ak-1” showed strongest response of POD (peroxidase) enzyme activity (0.4 U g−1 min−1) in 250 mg l−1 ALA solution. The highest CAT (catalase) activity (0.8 U g−1 min−1) after administration of 250 mg l−1 ALA was observed in “Li-1”. Meanwhile, highest (1.42 mg l−1) total chlorophyll content was also observed in “Ak-1”, when leaves were treated in 50 mg l−1 ALA, “Li-1” and “Ai-1” showed strongest response of specific activity of superoxide dismutase (SOD) in 50 mg l−1 and 50 mg l−1 ALA. Two hundred and fifty milligram per milliliter of ALA-treatment significantly improved the net photosynthetic rate.  相似文献   

10.
The Ortolan bunting Emberiza hortulana was censused in Poland during the Common Breeding Birds Monitoring Project in 2003–2009. Data from 683 monitoring polygons, covering in total more than 0.23% of the country, were used in the analysis. Based on the data and environmental information gathered in GIS databases (Corine land cover “CLC2000 and 2006” database, digital elevation model “GTOPO30” dataset, “Wordclim” dataset, and NDVI dataset), we modeled a habitat- and spatial-related variation of the Ortolan bunting’s presence. Birds were recorded in 13.2% grid cells. The mean density was 0.5 individual/km2. We modeled the spatial presence of birds using multivariate adaptive regression splines (MARS). Then models were cross-validated to check their consistency. The environment-use model shows that the Ortolan bunting prefers extensively cultivated farmland dominated by non-irrigated arable fields, small coniferous and mixed forests, complex cultivation patterns, and meadows. The preferred areas are located on lowlands in western and central parts of the country where the climate is the driest and warmest. Such a repeatable spatial pattern model of the population helped to create a predictive map of the Ortolan bunting’s presence in Poland. The general rule is that the probability gradient of its presence increases from the northeastern part of the country to the central and southwestern parts of Poland. Additionally, the Ortolan bunting avoids severe continental climate and regions with dense ground-level vegetation.  相似文献   

11.
The author's theory of the adoption of certain types of behavior patterns (Rashevsky, N., 1957, “Contributions to the Theory Initiative Behavior”.Bull. Maths. Biophysics,19, 91–119; 1968,Looking at History through Mathematics, Cambridge, Massachusetts: M.I.T. Press) consisting of elementary behaviors for each of which there is an opposite one and the two are mutually exclusive, is applied to describe the changes in the general type of behavior of a society. The elementary acts of which the whole problem consists may be either overt activities or beliefs or opinions. The general behavior patternsadopted by the society are considered as the “proper” or “just” ones. Any deviation from it in either one or more of the component elementary behaviors is considered as “unjust” and is subject to some punitive action. The total number of possible mutually exclusive behavior patterns is very large but finite. Within this very large range of possible patterns, we find that this notion of justice is relative, because changes from any behavior pattern to any other may occur. It is further shown that the amount of punishment for the deviation from the accepted pattern in order to be effective as well as efficient must be applied in different ways to different individuals even for the same transgression.  相似文献   

12.
Modifications of different EEG rhythms induced by a single neurofeedback session (by the EEG characteristics) directed toward an increase in the ratio of the spectral powers (SPs) of the α vs θ oscillations were compared with the psychological characteristics of the tested subjects (the group included 30 persons). A generally accepted neurofeedback technique was used; the intensity of acoustic white noise served as the feedback signal. EEG potentials were recorded from the C3 and C4 leads. Psychological testing was carried out using Eysenck’s (EPQ), Rusalov’s (OST), and (16 PF) questionnaires. The directions of changes in the SPs of EEG frequency components were found to significantly correlate with some individuality-related peculiarities of the tested subjects. The SP of the δ rhythm correlated with the EPQ scale “neuroticism,” OST scale “social plasticity,” and 16 PF factors H (“parmia”), I (“premsia”), and Q3 (“self-control of behavior”). The SP of the θ component demonstrated correlations with the OST scales “ergisity,” “plasticity,” and “social temp” and with 16 PF factors M (“autia”), Q4 (“frustration”), and Q1 (“exvia”). The SP of the α rhythm correlated with 16 PF factors Q3 (“self-control of behavior”), G (“strength of superEgo”), O (“hypothymia”), L (“protension”), and N (“shrewdness”). The SP of the β rhythm correlated with the OST scale “emotionality,” while that of the γ rhythm showed correlations with the 16 PF indices L (“protension”) and M (“autia”). Changes in the ratio of the α vs θ SPs correlated with the EPQ scale “neuroticism.” Thus, our data confirm the statement that a high individual variability of the results of a single (first in the series) neurofeedback session is to a great extent related to peculiarities of the individual psychological pattern of the subject. Neirofiziologiya/Neurophysiology, Vol. 38, No. 3, pp. 239–247, May–June, 2006.  相似文献   

13.
Summer phytoplankton blooms on the West Antarctic Peninsula (WAP) shelf result in episodic deposition of labile food material for benthic detritivores. This summer deposition is thought to enhance benthic recruitment of macro- and megafauna. To explore seasonality in benthic recruitment, juvenile invertebrates (>100 μm) were collected in a seasonal time series at three stations on the WAP continental shelf. 4,098 juveniles were collected (average densities 2,000–7,000 m−2), with polychaetes dominant (2,581 individuals). The majority of polychaetes showed evidence of enhanced recruitment prior to the summer bloom, although patterns varied across stations. Additional taxa showed recruitment peaks in summer, but again, patterns varied among stations. Based on observed patterns, polychaete taxa are classified as “seasonal”, “marginally seasonal”, and “non-seasonal” recruiters, with the latter two patterns predominating. The year-round presence of small juveniles in most taxa suggests that recruitment occurs continuously, with periodic enhancement. Year-round recruitment is consistent with the presence of a persistent “food bank” of labile organic material in WAP shelf sediments, allowing recruitment to be largely decoupled from seasonal bloom dynamics.  相似文献   

14.
Inherited medullary thyroid carcinomas (MTC) are aggressive and resistant to conventional chemo- and radiotherapies. We evaluated a novel strategy for treatment of MTC, combining “suicide” and interleukin-2 (IL-2) gene therapies. Tumors were produced in Wag/Rij rats by orthotopic injection of the rMTC 6–23 cell line, and/or derivatives expressing the herpes simplex virus 1 thymidine kinase (HSV1-TK) gene (rMTC-TK). Ganciclovir, a nucleoside analog selectively transformed to a toxic metabolite by HSV1-TK, totally eradicated rMTC-TK tumors in 60% of the animals. 1:1 rMTC and rMTC-TK mixed tumors were also strongly inhibited by ganciclovir (P < 0.05), indicating the occurrence of an efficient “bystander” effect in vivo. Double labelling of rMTC cell membranes and apoptotic nuclei revealed that, as with the TK+ cells, some TK cells died by apoptosis. A 1:1 mixture of rMTC and rMTC-TK cells was administered to produce established tumors and then rMTC cells, transfected to express the IL-2 gene (rMTC-IL2), were inoculated. Combined ganciclovir and IL-2 treatment improved the inhibition of tumor growth compared to that following ganciclovir alone (86% compared to 54%, P < 0.05). This treatment also significantly enhanced macrophage activation and tumor infiltration by CD8+ and CD4+ T lymphocytes. These results open an avenue for combining suicide and immunoregulatory gene therapies for MTC management in man. Received: 1 October 1998 / Accepted: 1 January 1999  相似文献   

15.
Source-sink landscape theory and its ecological significance   总被引:2,自引:0,他引:2  
Exploring the relationships between landscape pattern and ecological processes is the key topic of landscape ecology, for which, a large number of indices as well as landscape pattern analysis model were developed. However, one problem faced by landscape ecologists is that it is hard to link the landscape indices with a specific ecological process. Linking landscape pattern and ecological processes has become a challenge for landscape ecologists. “Source” and “sink” are common concepts used in air pollution research, by which the movement direction and pattern of different pollutants in air can be clearly identified. In fact, for any ecological process, the research can be considered as a balance between the source and the sink in space. Thus, the concepts of “source” and “sink” could be implemented to the research of landscape pattern and ecological processes. In this paper, a theory of sourcesink landscape was proposed, which include: (1) In the research of landscape pattern and ecological process, all landscape types can be divided into two groups, “source” landscape and “sink” landscape. “Source” landscape contributes positively to the ecological process, while “sink” landscape is unhelpful to the ecological process. (2) Both landscapes are recognized with regard to the specific ecological process. “Source” landscape in a target ecological process may change into a “sink” landscape as in another ecological process. Therefore, the ecological process should be determined before “source” or “sink” landscape were defined. (3) The key point to distinguish “source” landscape from “sink” landscape is to quantify the effect of landscape on ecological process. The positive effect is made by “source” landscape, and the negative effect by “sink” landscape. (4) For the same ecological process, the contribution of “source” landscapes may vary, and it is the same to the “sink” landscapes. It is required to determine the weight of each landscape type on ecological processes. (5) The sourcesink principle can be applied to non-point source pollution control, biologic diversity protection, urban heat island effect mitigation, etc. However, the landscape evaluation models need to be calibrated respectively, because different ecological processes correspond with different source-sink landscapes and evaluation models for the different study areas. This theory is helpful to further study landscape pattern and ecological process, and offers a basis for new landscape index design. __________ Translated from Acta Ecologica Sinica, 2006, 26(5): 1444–1449 [译自: 生态学报]  相似文献   

16.
An elevated number of Gr-1+CD11b+ myeloid-derived suppression cells (MDSCs) has been described in mice and human bearing tumor and associated with immune suppression. Arginase I production by MDSCs in the tumor environment may be a central mechanism for immunosuppression and tumor evasion. In this study and before, we found that Gr-1+CD11b+ MDSCs from ascites and spleen of mice bearing ovarian 18D carcinoma express a high level of PD-1, CTLA-4, B7-H1 and CD80 while other co-stimulatory molecules, namely CD40, B7-DC and CD86 are not detected. Further studies showed that PD-1 and CTLA-4 on the Gr-1+CD11b+ MDSCs regulated the activity and expression of arginase I. The blockage and silencing of PD-1, CTLA-4 or both PD-1 and CTLA4 molecules could significantly reduce arginase I activity and expression induced with tumor-associated factor. Similar results were also observed while their ligands B7-H1 and/or CD80 were blocked or silenced. Furthermore, CD80 deficiency also decreased the arginase I expression and activity. Antibody blockade or silencing of PD-1, CTLA-4 or both reduced the suppressive potential of PD-1+CTLA-4+MDSCs. Blockade of PD-1, CTLA-4 or both also slowed tumor growth and improved the survival rate of tumor-bearing mice. Thus, there may exist a coinhibitory and costimulatory molecules-based immuno-regulating wet among MDSCs. This research was supported by Nankai University grant, NSFC grant “30771967”, “985” grant,The Ministry of Science and Technology grant “2006AA020502”“06C26211200695”, Tianjin Grant “07JCZDJC03300” and “06ZHCXSH04800”.  相似文献   

17.
A method for estimating the complexity of behavioral patterns of ants based on the Kolmogorov complexity is considered. Behavioral sequences are presented as “texts” compressed with the KGB Archiver (v. 1.2). The elements of behavior (a total of 10) singled out from video records served as an alphabet. The comparison of “successful” and “incomplete” hunting behaviors in Myrmica rubra showed that successful hunting patterns were characterized by less complexity than “incomplete” ones. It was assumed that complete patterns had less redundancy and better predictability. The smallest complexity was revealed in complete hunting patterns of naive (laboratory reared) ants in comparison with members of a natural colony. In perspective, quantitative evaluation of complexity of behavioral patterns will help to evaluate the level of discrete variability within ant colonies.  相似文献   

18.
19.
The aim of this study was to activate, in mixed leukocyte/tumor cell cultures (MLTC), cytotoxic lymphocytes exhibiting preferential activity in vitro and in vivo towards allogeneic mouse lymphoma cells. Whereas the lymphoma target cells were readily lysed by the MLTC-derived lymphocytes, the cytotoxicity against the corresponding allogeneic concanavalin-A(ConA)-induced lymphoblasts was more than tenfold lower. Both activities were mediated by CD3+, TCR+, CD8+, CD4 cytotoxic T cells (CTL). ConA-induced lymphoblasts were readily lysed by anti-Thy1.2 antibodies and complement, by CTL derived from mixed leukocyte cultures (MLC) and by the MLTC-derived CTL in the presence of ConA, indicating that the lymphoblasts are not merely less lysable than the lymphoma cells but that the latter are specifically recognized by the CTL. Lymphoblasts poorly competed with 51Cr-labeled lymphoma cells in a “cold”-target competition assay, suggesting that the MLTC-derived CTL largely recognize epitopes expressed only by the lymphoma cells. Furthermore, analysis of the cytotoxic activity of more than 500 MLTC-derived CTL oligoclones and over 30 clones revealed that one-third of them were cytotoxic only against the allogeneic lymphoma cells, one-third were reactive against both the lymphoma and the allogeneic lymphoblast target cells and the remainder were not cytotoxic at all. Upon injection into sublethally irradiated, lymphoma-bearing allogeneic mice, the MLTC-derived CTL cured 56% of the recipients and caused graft versus host disease (GVHD) is only 22%, whereas CTL activated in MLC against allogeneic splenocytes were therapeutically ineffective and caused lethal GVHD in 89% of the recipients. Although the therapeutic efficacy of the in vitro-generated antitumor CTL was demonstrated against experimental lymphoma lines, this strategy might prove effective in tumor immunotherapy in conjunction with other modalities. Received: 24 December 1998 / Accepted: 5 April 1999  相似文献   

20.
There have been relatively few attempts to quantitatively describe behaviours in scincid lizards. Chalcides viridanus is a small body-sized skink endemic of Tenerife (Canary Islands). We describe and quantify 18 behaviour patterns (both social and agonistic) of this species, some of which have not been described before for other scincids. Video recordings of male–male, female–female, and male–female interactions were made under laboratory conditions, with controlled light–dark cycle and temperature. We describe several agonistic and courtship behaviour patterns. Within the first context, we detected a new agonistic behaviour for a scincid, “Snout to body”, that appeared at the beginning of agonistic sequences; it consisted of each animal placing its snout in contact with the other individual’s lateral side of the body. The amplitude of head movement during “Head bobbing” was lower than that described for many other lizard species. Agonistic behaviours were shown in intrasexual staged encounters both within males and females. The comparison of behaviour patterns of both types of intrasexual encounters showed that females were more active, exhibiting significantly higher frequencies of behaviour than males. Specifically, females showed the “Snout to body” pattern more frequently than males. In male–female encounters we detected courtship and copulation patterns only in April, when males performed “Bites” and “Snout to body” directed at females.  相似文献   

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