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Walter Malorni Pietro L. Indovina Giuseppe Arancia Stefania Meschini Maria T. Santini 《In vitro cellular & developmental biology. Plant》1990,26(4):399-410
Summary This paper describes the microscopic evidence supporting a cesium-induced delay in the fusion of chick embryo myoblast membranes
during in vitro myogenic differentiation. We have recently demonstrated that the sharp decrease in the conductivity and permittivity
of the membranes of these myogenic cells at the time of fusion is delayed 30 h by the addition of cesium to the culture medium
(Santini et al., Biochim. Biophys. Acta 945:56–64; 1988). We report here that this delay in fusion is substantiated by direct
microscopic observation and that cesium also induces ultrastructural changes in the myoblast cells themselves. Possible mechanisms
by which cesium may cause both the delay in fusion as well as the ultrastructural changes observed are discussed.
This investigation was partially supported by an Italian Consiglio Nazionale delle Ricerche grant 85.00.304.02 (to P. L. I.). 相似文献
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Ciliary neurotrophic factor inhibits brain and peripheral tumor necrosis factor production and, when coadministered with its soluble receptor, protects mice from lipopolysaccharide toxicity. 总被引:3,自引:0,他引:3
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F. Benigni P. Villa M. T. Demitri S. Sacco J. D. Sipe L. Lagunowich N. Panayotatos P. Ghezzi 《Molecular medicine (Cambridge, Mass.)》1995,1(5):568-575
BACKGROUND: The receptor of ciliary neurotrophic factor (CNTF) contains the signal transduction protein gp130, which is also a component of the receptors of cytokines such as interleukin (IL)-6, leukemia-inhibitory factor (LIF), IL-11, and oncostatin M. This suggests that these cytokines might share common signaling pathways. We previously reported that CNTF augments the levels of corticosterone (CS) and of IL-6 induced by IL-1 and induces the production of the acute-phase protein serum amyloid A (SAA). Since the elevation of serum CS is an important feedback mechanism to limit the synthesis of proinflammatory cytokines, particularly tumor necrosis factor (TNF), we have investigated the effect of CNTF on both TNF production and lipopolysaccharide (LPS) toxicity. MATERIALS AND METHODS: To induce serum TNF levels, LPS was administered to mice at 30 mg/kg i.p. and CNTF was administered as a single dose of 10 micrograms/mouse i.v., either alone or in combination with its soluble receptor sCNTFR alpha at 20 micrograms/mouse. Serum TNF levels were the measured by cytotoxicity on L929 cells. In order to measure the effects of CNTF on LPS-induced TNF production in the brain, mice were injected intracerebroventricularly (i.c.v.) with 2.5 micrograms/kg LPS. Mouse spleen cells cultured for 4 hr with 1 microgram LPS/ml, with or without 10 micrograms CNTF/ml, were also analyzed for TNF production. RESULTS: CNTF, administered either alone or in combination with its soluble receptor, inhibited the induction of serum TNF levels by LPS. This inhibition was also observed in the brain when CNTF and LPS were administered centrally. In vitro, CNTF only marginally affected TNF production by LPS-stimulated mouse splenocytes, but it acted synergistically with dexamethasone (DEX) in inhibiting TNF production. Most importantly, CNTF administered together with sCNTFR alpha protected mice against LPS-induced mortality. CONCLUSIONS: These data suggest that CNTF might act as a protective cytokine against TNF-mediated pathologies both in the brain and in the periphery. 相似文献
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Giovanni Mita Carmela Gerardi Antonio Miceli Roberto Bollini Pietro De Leo 《Plant cell reports》1994,13(7):406-410
Summary An in vitro culture of Alkanna tinctoria Tausch cells was set up in order to investigate the possibility of producing alkannin, a red naphthoquinone naturally present in the root bark of this plant. Furthermore, an in vitro culture of callusderived roots was established and the production of alkannin evaluated. In the different experimental conditions investigated, differences in the production of alkannin derivatives as well as in the type of pigments produced, were observed. The potential use of this technology is discussed. 相似文献
17.
Carlo Capelli Guglielmo Antonutto Paola Zamparo Massimo Girardis Pietro Enrico di Prampero 《European journal of applied physiology and occupational physiology》1993,66(3):189-195
The mechanical power (Wtot, W·kg–1) developed during ten revolutions of all-out periods of cycle ergometer exercise (4–9 s) was measured every 5–6 min in six subjects from rest or from a baseline of constant aerobic exercise [50%–80% of maximal oxygen uptake (VO2max)] of 20–40 min duration. The oxygen uptake [VO2 (W·kg–1, 1 ml O2 = 20.9 J)] and venous blood lactate concentration ([la]b, mM) were also measured every 15 s and 2 min, respectively. During the first all-out period, Wtot decreased linearly with the intensity of the priming exercise (Wtot = 11.9–0.25·VO2). After the first all-out period (i greater than 5–6 min), and if the exercise intensity was less than 60% VO2max, Wtot, VO2 and [la]b remained constant until the end of the exercise. For exercise intensities greater than 60% VO2max, VO2 and [la]b showed continuous upward drifts and Wtot continued decreasing. Under these conditions, the rate of decrease of Wtot was linearly related to the rate of increase of V [(d Wtot/dt) (W·kg–1·s–1) = 5.0·10–5 –0.20·(d VO2/dt) (W·kg–1·s–1)] and this was linearly related to the rate of increase of [la]b [(d VO2/dt) (W·kg–1·s–1) = 2.310–4 + 5.910–5·(d [la]b/dt) (mM·s–1)]. These findings would suggest that the decrease of Wtot during the first all-out period was due to the decay of phosphocreatine concentration in the exercising muscles occurring at the onset of exercise and the slow drifts of VO2 (upwards) and of Wtot (downwards) during intense exercise at constant Wtot could be attributed to the continuous accumulation of lactate in the blood (and in the working muscles). 相似文献
18.
Pietro Cugini Loredana Di Palma Salvatore Di Simone Piernatale Lucia Paola Battisti Alessandro Coppola Giuseppe Leone 《Chronobiology international》1993,10(1):73-78
This study aimed to explore the 24-h patterns of stroke volume, cardiac output, and peripheral vascular resistance along with other correlated variables, such as left ventricular ejection time, ejection velocity index, thoracic fluid index, heart rate, and blood pressure. The study was performed on 12 clinically healthy subjects by means of a noninvasive beat-to-beat monitoring using the thoracic electric bioimpedance technique associated with the automated sphygmomano-metric recording. Time data series were analyzed by means of chronobiological procedures. The results documented the occurrence of a circadian rhythm for all the variables investigated, giving relevance to the beat-to-beat bioperiodicity of cardiac output and peripheral vascular resistance. Temporal quantification of the investigated variables may be useful for a better insight of the chronophysiology of the cardiovascular apparatus. 相似文献
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20.
Claudia M. Caillaud J. S. Pierre B. Chaubet J. P. Di Pietro 《Entomologia Experimentalis et Applicata》1995,75(1):9-18
The behaviour ofSitobion avenae (F.), was compared on resistant wheat lines ofTriticum monococcum (L.) and a susceptible variety ofTriticum aestivum (L.). Firstly, stylet penetration activities were monitored with the Electrical Penetration Graph (EPG) technique and subsequently
analysed using flow charts combined with correspondence analysis. Plant resistance was shown to be associated with repeated
penetrations without access to either the xylem or the phloem, and with numerous failures in starting a sustained sap ingestion
(as represented by pattern E2). Access to sieve elements of the phloem did not seem to be much affected on resistant plants
but it took the aphid three times as long to produce a sap ingestion pattern when maintained on the resistant lineT. monococcum no 44 (Tm44) as compared with aphids maintained on susceptible plants. As a result the total time spent in ingesting from sieve
elements was reduced by 72% on Tm44. Secondly, direct observations of freely-moving apterous adults were performed. Aphids
did not discriminate between resistant and susceptible wheat during the first 30 min of access to test leaves, but only 4
out of 25 aphids were still probing after eight hours on resistant Tm44.
The relevance of these results to possible location of the resistance factor(s) are discussed. Although detection of plant
resistance before sieve elements are reached can not be rigorously excluded, the factors involved inT. monococcum resistance toS. avenae undoubtedly occur within the phloem vessels. 相似文献