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21.
Thomas J. Anderson Carol A. Lapp Michael A. Billman George S. Schuster 《Journal of clinical periodontology》1998,25(1):48-55
Abstract. Both transforming growth factor-β (TGF-ß) and platelet-derived growth factor (PDGF) have been shown to affect cell proliferation in vitro. The hypothesis being tested was that the effects of the 2 cytokines would be modulated by the presence of serum in the medium. Gingival fibroblasts, obtained from periodontally healthy patients, were maintained in primary culture. Dose response experiments were performed for each growth factor in serum-free medium and in medium containing natural or heat-inactivated fetal bovine serum (10% FBS). Changes in cell numbers were quantified by crystal violet staining. The optimal concentrations of the individual factors (10 ng/ml TGF-ßI, 20 ng/ml PDGF-BB) were then used when the 2 factors were tested in various sequences. In serum-free medium or in medium with 10% natural serum, the response to PDGF-BB was dose-dependent up to 40 ng/ml; however, with 10% heat-inactivated serum, the maximal response was seen at 20 ng/ml. The largest increase in cell numbers was produced by the simultaneous exposure to the two cytokines, rather than a sequential presentation. The findings suggest that the 48-h growth response of human gingival fibroblasts to 10 ng/ml TGF-ß1 or 20 ng/ml PDGF-BB in serum-free medium was equivalent to growth obtained in medium containing heat-inactivated 10% FBS without added growth factors. 相似文献
22.
I. O. Skalpe J. F. Bonneville P. Grane C. Gyldenstedt B. Otto D. T. Kristoffersen M. G. Svaland 《European radiology》1998,8(6):1054-1057
The purpose of this study was to evaluate and compare the radiographic efficacy and safety of iodixanol (Visipaque; 270 and
320 mg I/ml) and iohexol (Omnipaque; 300 mg I/ml) in myelography. The study was randomized, double-blind and comparative including
398 patients from five European university clinics. The radiographic visualisation was evaluated as poor, good or excellent.
Adverse events were recorded by interviewing the patients after the myelography, and each patient was given a questionnaire
to be returned after 1 week. In cervical myelography with cervical puncture more films with excellent quality was obtained
after iodixanol 320 mgI/ml compared with iohexol 300 mgI/ml (p = 0.009). Also in lumbar myelography iodixanol 320 mgI/ml compared favourably with iohexol 300 mgI/ml (p = 0.006). The most frequent adverse event was headache, which occurred in 5–35 % of patients during the first 24 h and in
19–61 % within the first 7 days, depending on the centre. There was no difference in frequency and severity of the adverse
effects between the contrast media.
Received 13 March 1997; Revision received 29 December 1997; Accepted 5 January 1997 相似文献
23.
Besides intrinsic determinants of cell growth, epigenetic signals have been proposed to regulate development and maintenance of neurons. Here we provide evidence that cerebral astrocytes contribute significantly to the set of environmental influences that are required for long-term survival of neurons derived from the mammalian central nervous system. Cerebral astrocytes in serum-free culture express diffusible and non-diffusible neuron-supporting signals, including cell-adhesive neurite growth-promoting glycoproteins, diffusible neurotrophic factors as well as membrane-bound molecules that mediate cell contact interactions. The combination and synergistic interaction of these environmental signals markedly enhance the survival of brain neurons. While astroglia-derived cell-adhesive substrates that include a high molecular weight complex consisting of laminin β-chains and proteoglycan (Matthiessen et al., 1989) stimulate neurite outgrowth, they fail to enhance long-term neuronal survival when additional neurotrophic and cell-contact interactions are lacking. Astrocytes release a diffusible neurotrophic activity that, when permanently applied, maintains long-term survival of central neurons in culture. The soluble neurotrophic activity seems to interact synergistically with cell-bound signals which are also required for long-term survival and which are expressed by astrocytes and neurons, but not by fibroblasts. Among neurons from different brain areas, such as hippocampus, cerebral cortex and septum, regional differences in their responsiveness to the astroglial neurotrophic activity have been observed. 相似文献
24.
I. A. Volchegorskii A. V. Vlasov G. E. Livshits E. M. Akhkyamov N. A. Skobeleva R. I. Lifshits L. Ya. Ebert 《Bulletin of experimental biology and medicine》1995,119(2):150-153
Three identical oligopeptide-containing fractions of so-called “medium molecules”, isolated by sequential ultrafiltration
and gel chromatography from the blood of 8 intact dogs and 15 dogs with an extensive thermal burn, were examined for their
impact on phagocytic cells (neutrophil granulocytes and macrophages) in relation to the molecular-weight distribution of the
molecules. The relatively high-polymer fractions of medium molecules, unlike oligomeric fractions, stimulated the phagocytic
activity of these cells. Because of their increased polymerism, the fractions of medium molecules from dogs with thermal trauma
stimulated phagocytosis to a greater extent than did those from intact animals.
Translatedfrom Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N
o
2, pp. 159–162, February, 1995
Presented by V. A. Trufakin, Member of the Russian Academy of Medical Sciences 相似文献
25.
Chernyshev BV Panasyuk YA Semikopnaya II Timofeeva NO 《Neuroscience and behavioral physiology》2004,34(9):907-918
Spike activity was studied in 95 neurons in the basal magnocellular nucleus in rabbits during spontaneous behavior and during performance of a conditioned operant response. Nearly half the neurons (48.4%) showed significant (p < 0.05) negative correlations between spontaneous discharges and the power of the frontal lobe EEG delta rhythm; most of these cells could be identified as cholinergic projection neurons. Neurons of this group had predominantly excitatory responses to the conditioned stimulus during performance of the operant task, while the responses to the conditioned stimulus of presumptively non-cholinergic neurons, not projecting to the cortex, were mainly inhibitory. The activatory responses of neurons in the basal magnocellular nucleus to the conditioned stimulus were markedly stronger while the animals performed the operant response as compared with performances in which there was no response to the conditioned stimulus. These results provide evidence that the basal magnocellular nucleus supports the level of waking and attending required for performance of operant conditioned reflex activity. 相似文献
26.
Human sperm chemotaxis: both the oocyte and its surrounding cumulus cells secrete sperm chemoattractants 总被引:5,自引:0,他引:5
Sun F Bahat A Gakamsky A Girsh E Katz N Giojalas LC Tur-Kaspa I Eisenbach M 《Human reproduction (Oxford, England)》2005,20(3):761-767
BACKGROUND: Human sperm chemotaxis to pre-ovulatory follicular fluid is well established in vitro. However, it is not known whether the female's oocyte-cumulus complex secretes sperm chemoattractants subsequent to ovulation (for enabling sperm chemotaxis within the Fallopian tube) and, if so, which of these cell types--the oocyte or the cumulus oophorus--is the physiological origin of the secreted chemoattractant. METHODS: By employing a directionality-based chemotaxis assay, we examined whether media conditioned with either individual, mature (metaphase II) human oocytes or the surrounding cumulus cells attract human sperm by chemotaxis. RESULTS: We observed sperm chemotaxis to each of these media, suggesting that both the oocyte and the cumulus cells secrete sperm chemoattractants. CONCLUSIONS: These observations suggest that sperm chemoattractants are secreted not only prior to ovulation within the follicle, as earlier studies have demonstrated, but also after oocyte maturation outside the follicle, and that there are two chemoattractant origins: the mature oocyte and the surrounding cumulus cells. 相似文献
27.
P V Simonov 《International journal of psychophysiology》1984,1(3):277-289
As an evolvement of Pavlov ideas on higher nervous (psychic) activity 'the need-informational theory of emotions' was suggested by the author in 1964. According to it an emotion is a function of two major factors: (1) power and quality of actual need (or drive, or motivation) and (2) estimation of probability (possibility) of need satisfaction on the basis of phylo- and ontogenetic experience. In the process of experimental testing of 'the need-informational theory of emotions' the role of different cerebral structures (frontal neocortex, hippocampus, amygdala, hypothalamus) in the genesis of emotional states and in the organization of goal-directed behavior was elucidated. The experimental data showed that these 4 brain structures play the major role in estimation of signals coming from environment and in the choice of subject's reactions. The individual characteristics of the interaction between the 4 brain structures must be taken into consideration in discussing neurophysiological backgrounds of different types of the higher nervous activity (temperaments), parameters of extra-introversion and neurotism (emotionality), the formation of main types of neurosis. 相似文献
28.
Metabolic pathways leading to lipid biosynthesis in four different developmental stages of Schistosoma mansoni were explored and quantified by incubation in the presence of labeled precursors in a chemically defined medium. At the schistosomulum stage and in male, female, or paired worms, glycerol and oleate incorporation into neutral lipids, mainly in the form of triacylglycerols, was greater than into phospholipids, whereas in 11-and 15-day-old worms, synthesis mainly led to phospholipids. Incorporation into phospholipids was recovered largely in phosphatidylcholine, and distribution into other phospholipids depended on the developmental stage. Incorporation of choline and ethanolamine into their respective phospholipids represented up to 15% of the parasitic phospholipid content. The formation of phosphatidylcholine by phosphatidylethanolamine methylation occurred mainly in the immature parasitic stages. Inositol incorporation was also measurable, whereas [14C]serine incorporation was low or undetectable. Addition of 1-palmitoyl-2-[14C]oleyl phosphatidylcholine revealed a very high uptake of this phospholipid by the immature stages but further metabolism was not detectable. In contrast, adult S. mansoni were completely unable to take up or absorb this exogenous phospholipid. The most striking aspect of this study was the relatively high metabolic activity in 11-day-old worms and the lower but sustained activity on day 15 and at the schistosomulum stage. By comparison, biosynthetic activity in adult S. mansoni, on which research studies have been focused until now, was very low. We also discuss the participation of lipid metabolism in the constant renewal of the membrane complex which is essential to parasitism by S. mansoni. 相似文献
29.
本文制备了巨噬细胞条件培养基(MφCM),并应用快速自动比色微量分析法检测MφCM对体外培养的生后7dSD大鼠小脑皮质神经元的作用。结果表明,分子量大于10kD的MφCM对神经元(细胞密度1×106/ml)的作用,与对照组比较有明显的神经营养活性(F<0.05);用盖玻片培养法表明,该组份有促进神经元突起生长的作用。MφCM经SephacrylS-100-HR凝胶层析和生物活性鉴定,获得了具有神经营养活性的第二峰洗脱液。此洗脱液经SDS-聚丙烯酰胺凝胶电泳分析,证明MφCM中神经营养活性成份的蛋白质其分子量为31kD-68kD之间。 相似文献
30.
Using the soft-agar colony assay, we have generated three MT3-associated clones: HJ1, HJ13, and HJ39, from an MLR combination of two unrelated individuals. Another clone, HJ37, appeared to recognize a novel HLA-D determinant. PLT inhibition studies with monoclonal anti-Ia-like antibodies (Mab) were conducted on clones HJ1, HJ39, and HJ37. Five different anti-DR Mab had no significant inhibitory effect on these clones. On the other hand, two Mab SG171 and Q5/13 which appear to react with DR and MT3 (I-A like) molecules strongly inhibited the two MT3-specific PLT clones. While SG171 and Q5/13 had little effect on HJ37, it was observed that a polymorphic Mab 17.15 had a strong inhibitory effect. These results, in concordance with biochemical data on Ia molecules precipitated by these Mab, suggest that these alloreactive clones may recognize non-DR PLT determinants. They also provide further indirect support that MT3 molecules represent the human homologue of murine I-A molecules. 相似文献