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11.
M Bernardi B Di Sarra G Montecchiani L Re L Rossini C Tonnini 《Bollettino della Società italiana di biologia sperimentale》1991,67(1):47-54
Spontaneous fluctuations in heart rate were analyzed by spectral analysis in the ether anesthetized and pithed adult rat. In order to investigate the changes in the spectral pattern of the fluctuations, the selective 5HT-2 and -3 isoreceptor blockers ritanserin and BRL 43694A were used. In both the experimental conditions, ritanserin blockade led to dose-dependent increased fluctuations in HR low and high frequencies. In both the anesthetized and pithed rats, the low frequency range HR fluctuations were drastically reduced by BRL 43694A. 相似文献
12.
Phenylarsine oxide induces the cyclosporin A-sensitive membrane permeability transition in rat liver mitochondria 总被引:2,自引:0,他引:2
Ewa Lenartowicz Paolo Bernardi Giovanni Felice Azzone 《Journal of bioenergetics and biomembranes》1991,23(4):679-688
This paper reports an investigation on the effects of the hydrophobic, bifunctional SH group reagent phenylarsine oxide (PhAsO) on mitochondrial membrane permeability. We show that PhAsO is a potent inducer of the mitochondrial permeability transition in a process which is sensitive to both the oxygen radical scavanger BHT and to cyclosporin A. The PhAsO-induced permeability transition is stimulated by Ca2+ but takes place also in the presence of EGTA in a process that maintains its sensitivity to BHT and cyclosporin A. Our findings suggest that, at variance from other known inducers of the permeability transition, PhAsO reacts directly with functional SH groups that are inaccessible to hydrophilic reagents in the absence of Ca2+. 相似文献
13.
Ester Cecere Orestina D. Saracino Margherita Fanelli Antonella Petrocelli 《Journal of applied phycology》1992,4(4):323-327
A survey is reported of the drifting algal community in Mar Piccolo, a polluted basin subject to sewage outlets. The key role was played by a few key species, mainly floridean red algae. 相似文献
14.
Antonella Angiolillo Fausto Panara Gina Piccinini Gian Luigi Gianfranceschi 《Molecular biology reports》1991,15(1):39-43
A protein kinase, type NII, has been purified from wheat germ chromatin. The enzyme, which uses both ATP and GTP as phosphoryl donors, catalyzes the phosphorylation of casein, phosvitin and E. coli RNA polymerase, but not of histone proteins. Polypeptide bands at 46 kDa, 37 kDa and 25 kDa were estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Autophosphorylation of the 25 kDa subunit was observed following incubation of the purified kinase with (-32P)ATP and (-32P)GTP. 相似文献
15.
Leandro Medrano Giacomo Bernardi Jérome Couturier Bernard Dutrillaux Giorgio Bernardi 《Chromosoma》1988,97(2):178-183
The diploid chromosome number of the Chinese raccoon dog varies from 54 (no B chromosomes) to 58 (4 B chromosomes). The B chromosomes are totally heterochromatic. An electron microscopic study was made of the synaptonemal complexes (SC) in spermatocytes of these animals. The SC karyotype consists of 27 regular chromosome pairs (autosomes and the sex chromosomes) plus the B chromosomes. The Bs pair effectively with one another at pachytene, but the SC axes of the B chromosomes are much denser than those of the A chromosomes. Depending on the number of Bs, both bivalents and multivalents have been observed. When three B chromosomes are present in a cell, parallel alignment of all three SCs can be seen. Formation of multivalents indicates high homology among these supernumerary heterochromatic chromosomes. Fusiform bulges are found along unpaired regions of all chromosomes which are particularly pronounced in diplotene. 相似文献
16.
Pinsky M. R.; Matuschak G. M.; Bernardi L.; Klain M. 《Journal of applied physiology》1986,60(2):604-612
Changes in intrathoracic pressure (ITP) can influence cardiac performance by affecting ventricular loading conditions. Because both systemic venous return and factors determining left ventricular (LV) ejection may vary over the cardiac cycle, phasic increases in ITP may differentially affect preload or afterload if delivered at specific points within the cardiac cycle. We studied the hemodynamic effects of cardiac cycle-specific increases in ITP (pulses) delivered by a high-frequency jet ventilator in an acute closed-chested canine model (n = 11), using electromagnetic flow probes to measure biventricular stroke volume. Measurements were taken during a control condition after the induction of acute ventricular failure (AVF) by propranolol hydrochloride and volume infusion. ITP was independently varied without changing lung volume by the inflation of thoracoabdominal binders. Although synchronous pulses had minimal hemodynamic effects in unbound controls, binding pulses timed to occur in early diastole resulted in decreases in LV filling pressure and left ventricular stroke volume (SVlv) (P less than 0.05). In the AVF condition, pulses increased LV performance, evidenced by increases in SVlv (P less than 0.01), despite decreases in LV filling pressure (P less than 0.05). This effect is maximized by binding and by timing the pulses to occur in systole. We conclude that cardiac cycle-specific increases in ITP can significantly affect cardiac performance. These effects appear to be related to the ability of such timed pulses to selectively affect LV preload and afterload. 相似文献
17.
Reduced mechanical activity of perfused rat heart following morphine or enkephalin peptides administration 总被引:1,自引:0,他引:1
Carlo Clô Claudio Muscari Benedetta Tantini Carla Pignatti Pasquale Bernardi Carlo Ventura 《Life sciences》1985,37(14):1327-1333
In the isolated and perfused rat heart, the addition of morphine, methionine-enkephalin or leucine-enkephalin to the coronary perfusate, significantly reduces the mechanical activity by negatively affecting both the heart rate and the developed tension. These effects are dose dependent and maximally evident with leucine-enkephalin. Furthermore all the opioids strongly reduce the activity of isoproterenol-stimulated hearts. The suggestion is made that opioid peptides directly influence the cardiac mechanical activity possibly by interacting with membrane-receptor systems. 相似文献
18.
19.
Pathway for uncoupler-induced calcium efflux in rat liver mitochondria: inhibition by ruthenium red 总被引:3,自引:0,他引:3
The rate of uncoupler-induced Ca2+ efflux from rat liver mitochondria is increased by acetate and decreased by phosphate. This effect depends on a shift of the apparent Km, which is increased by phosphate and decreased by acetate, while the Vmax is not modified. The modification of the apparent Km by permeant anions presumably reflects changes in the concentration of matrix free Ca2+. A major part of uncoupler-induced Ca2+ efflux is sensitive to Ruthenium Red, the specific inhibitor of the Ca2+ uniporter , but an apparent insensitivity is observed when the H+ permeability is rate limiting in the process of Ca2+ efflux. The titer of uncoupler required for maximal stimulation of Ca2+ efflux increases with the Ca2+ load and may be 1-2 orders of magnitude higher than that required for maximal stimulation of respiration. On the other hand, when the uncoupler concentration is raised above 10(-6) M, the process of Ca2+ efflux becomes again Ruthenium Red insensitive. The Ruthenium Red inhibition of uncoupler-induced Ca2+ efflux is time dependent, in that the degree of inhibition exerted by low amounts of Ruthenium Red increases with the incubation time. Since the inhibition of the rate of Ca2+ influx undergoes a parallel relief, it is possible that Ruthenium Red moves from the cytosolic to the matrix side of the inner membrane. It is concluded that, in native mitochondria, uncoupler-induced Ca2+ efflux occurs via reversal of the uniport Ca2+ carrier, and not through activation of an independent pathway. 相似文献
20.
Intramolecular transposition of IS102 总被引:1,自引:0,他引:1
It has been postulated that deletions mediated by transposable elements are intramolecular transposition events. An implication of this hypothesis is that the deleted fragment may be recovered if it is capable of autonomous replication. We report here the characterization of the products of intramolecular transposition of the element IS102 in bireplicons. We show that when two origins (ori's) (of pSC101 and R6-5) generate the same copy numbers, two dissociated replicons are recovered as well as the inversions. On the contrary, when two ori's (of pSC101 and pBR322) have different copy numbers, intramolecular transposition results essentially in inversions. However, the very low frequency (5 X 10(-8)) at which intramolecular transpositions in the bireplicons occurs, as compared to the single replicon (10(-4)), suggests that a complete transposition reaction may not be necessary to generate deletions. 相似文献