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41.
Donatella Marazziti Lionella Palego Chiara Mazzanti Stefano Silvestri Giovanni B. Cassano 《Chronobiology international》1995,12(2):100-105
Our study aimed to investigate the possible presence of seasonal changes in platelet phenolsulfotransferase (ST) in a group of 20 healthy, drug-free subjects of both sexes and between 24 and 37 years of age. Blood samples were taken four times a year in the period immediately following the equinoxes and the solstices. The results showed that both STs underwent seasonal changes: the lowest values were found in autumn and in winter, and the highest in the summer. A positive correlation between the two STs and the length of the photoperiod was observed in winter, whereas in the spring we detected a negative correlation between the TL ST and the photoperiod length. Future studies should clarify whether platelet ST of patients with mood disorders shows a similar seasonality. 相似文献
42.
Fabrizio Barberini Stefano Sartori Dr. Pietro Motta Jonathan Van Blerkom 《Cell and tissue research》1978,190(2):207-222
Summary Changes occurring on the surface of the uterine luminal epithelium of the rabbit during the estrous and progestational stages of the reproductive cycle were examined by scanning and transmission electron microscopy. The findings demonstrate that the uterine epithelium, or endometrium, contains two cell types: ciliated cells and nonciliated, microvillous cells. In estrous animals, ciliated cells, although not very numerous, were usually observed in small groups. However, at increasing intervals of time following mating, ciliated cells progressively disappeared from the endometrium until approximately eight to ten days post coitum, when they became scare. From several hours to four to five days following mating, extensive changes occurred on the surfaces of microvillous cells. When observed by TEM, these elements contained organelles typical of cells involved in the synthesis and secretion of glycoproteins. Furthermore, microvillous cells during this period displayed numerous apical protrusions of different sizes and shapes and containing material of varying electron density. Parallel SEM examinations of the same material confirmed the presence of these protrusions. Some of the protrusions appeared as spheroidal masses attached to the cytoplasm by means of a cytoplasmic strand. Other surface masses were clearly unattached to the cell surface and were distributed (1) on the surface of microvillous cells, (2) on the cilia of adjacent ciliated cells, and (3) on the surface of spermatozoa.Changes occurring on the luminal surface during the early postcoital period are interpreted as an expression of morphodynamic processes likely involving coupled secretion (exocytosis) and resorption (endocytosis) of luminal material. The observations presented here also demonstrate that between six and ten days post coitum, the rabbit endometrium contained increasing numbers of enlarged, nonciliated cells that probably arose by the fusion of smaller, microvillous elements.The work reported here was supported by C.N.R. contracts No. CT 760128809 and CT 77014239 (to P.M.) and NIH. Grant HD-04274 (to J.V.B.) 相似文献
43.
44.
C Mangoni di S Stefano M Ruggiero M Brunese S Morelli 《Bollettino della Società italiana di biologia sperimentale》1979,55(14):1398-1404
Metabolic rate of obese patients is reported, recorded to cellular active mass. The metabolic rate is higher in obese patients and the value is diucthy related to individual actual weight. The dinamic-specific action of proteins is normal. 相似文献
45.
Giovanni Felice Azzone Stefano Massari Tullio Pozzan 《Molecular and cellular biochemistry》1977,17(2):101-112
Summary The evidence that all energy transducing membranes can generate a proton electrochemical potential difference,
H, across the membrane and that this potential can be used to transfer energy among energy transducing units and to generate ATP, has increased the interest for the view that
H plays an obligatory role in energy transduction and ATP synthesis. In the present article we shall concentrate on two experimental questions related with the generation and role of
H: (a) the charge/site ratio; (b) the relation between the proton electrochemical potential on one side and the cation electrochemical potential, the phosphate potential and the redox potential on the other. We shall then discuss the view that energy transduction corresponds to a molecular energy machine rather than to a fuel cell. 相似文献
46.
Mario Maggi Guido Fantoni Alessandro Peri Stefano Giannini Maria Luisa Brandi Claudio Orlando Mario Serio 《The Journal of steroid biochemistry and molecular biology》1991,40(4-6):481-491
Oxytocin (OT) and V1 vasopressin (VP) receptors are present simultaneously in several tissues, including the uterus. In myometrium these receptors mediate contractility, while in endometrium they mediate the release of other uterotonic substances as endothelin (ET). In rabbit myometrium, estrogens increase, while progesterone blunts neurohypophysial hormone receptors. However, the action of sex steroids on OT and V1 VP receptors differs in terms of the ED50 and maximal effect. Therefore, at parturition, only OT receptors show a dramatic rise, while V1 VP receptors do not change, suggesting a major role for OT in labor. ET is a potent stimulator of uterine activity acting through specific receptors present on myometrial cells. These receptors as well as the endometrial localization of ET are modulated by sex steroids, indicating that ET might represent a paracrine regulator of uterine activity. In humans, OT but not V1 VP receptors increase as pregnancy progresses, confirming the primary relevance of OT in timing delivery. 相似文献
47.
Olimpia Meucci Maurizio Grimaldi Antonella Scorziello Stefano Govoni Stefania Bergamaschi Takeshi Yasumoto† Gennaro Schettini 《Journal of neurochemistry》1992,59(2):679-688
The biological activities of maitotoxin are strictly dependent on the extracellular calcium concentration and are always associated with an increase of the free cytosolic calcium level. We tested the effects of voltage-sensitive calcium channel blockers (nicardipine and omega-conotoxin) on maitotoxin-induced intracellular calcium increase, membrane depolarization, and inositol phosphate production in PC12 cells. Maitotoxin dose dependently increased the cytosolic calcium level, as measured by the fluorescent probe fura 2. This effect disappeared in a calcium-free medium; it was still observed in the absence of extracellular sodium and was enhanced by the dihydropyridine calcium agonist Bay K 8644. Nicardipine inhibited the effect of maitotoxin on intracellular calcium concentration in a dose-dependent manner. The maitotoxin-induced calcium rise was also reduced by pretreating cells with omega-conotoxin. Pretreatment of cells with maitotoxin did not modify 125I-omega-conotoxin and [3H]PN 200-110 binding to PC12 membranes. Nicardipine and omega-conotoxin inhibition of maitotoxin-evoked calcium increase was reduced by pertussis toxin pretreatment. Maitotoxin caused a substantial membrane depolarization of PC12 cells as assessed by the fluorescent dye bisoxonol. This effect was reduced by pretreating the cells with either nicardipine or omega-conotoxin and was almost completely abolished by the simultaneous pretreatment with both calcium antagonists. Maitotoxin stimulated inositol phosphate production in a dose-dependent manner. This effect was reduced by pretreating the cells with 1 microM nicardipine and was completely abolished in a calcium-free EGTA-containing medium. The findings on maitotoxin-induced cytosolic calcium rise and membrane depolarization suggest that maitotoxin exerts its action primarily through the activation of voltage-sensitive calcium channels, the increase of inositol phosphate production likely being an effect dependent on calcium influx. The ability of nicardipine and omega-conotoxin to inhibit the effect of maitotoxin on both calcium homeostasis and membrane potential suggests that L- and N-type calcium channel activation is responsible for the influx of calcium following exposure to maitotoxin, and not that a depolarization of unknown nature causes the opening of calcium channels. 相似文献
48.
To lek or not to lek: mating strategies of male fallow deer 总被引:5,自引:1,他引:4
Apollonio Marco; Festa-Bianchet Marco; Mari Franco; Mattioli Stefano; Sarno Benedetta 《Behavioral ecology》1992,3(1):25-31
We studied the mating system of fallow deer (Dama dama) for6 years in central Italy. Males in this population could defendterritories that were either single, clumped in leks, or satelliteto leks. The most highly successful males in our study werein leks. When we considered all males, there were no significantdifferences in average copulatory success according to territorytype because many lek males did not achieve any copulations,which were seen in only a few lek territories. The variancein copulatory success, however, was much greater for leks thanelsewhere. Single territories were occupied for shorter timesduring the rut than lek territories. Fighting among males wasmore frequent in the lek, even when we excluded highly successfullek males from the analysis. Chases of nonterritorial malesand harem size were correlated with the number of copulationsachieved by individual males, but did not vary according toterritory type. Copulatory success of some individuals increasedwith age, but there were no age differences among males holdingdifferent types of territories. Satellite males switched tolek territoriality in the course of one rut, but switches fromsingle territory to lek territory were rare. We suggest thatmales in single territories are inferior competitors that selecta low-risk, lowbenefit strategy, whereas those in lek territorieswhere no copulations were seen may be attempting to establishthemselves on the lek to increase their copulatory success infuture years. 相似文献
49.
Comparative aspects of opioid-dopamine interaction 总被引:5,自引:0,他引:5
George B. Stefano 《Cellular and molecular neurobiology》1982,2(3):167-178
1. Opiate receptors are found in invertebrate as well as mammalian systems, often in proximity to dopamergic systems. This review summarizes the interrelationships between these two transmitter systems in invertebrates. 2. The comparative data discussed here are of considerable significance. They recall that the opioid-dopamine relationships first demonstrated in the mammalian nervous system also apply to invertebrates and are therefore of more general importance. The results obtained in the mollusk Mytilus strengthen the concept that the activity of dopaminergic neurons may be modulated by afferent opioid signals and that, even in "more primitive" animals, interneuronal transfer of information is more complex than formerly visualized. Furthermore, the data indicate that endogenous opioids may exert tonic control over dopamine metabolism, thus implying interdependence of the two systems. 相似文献
50.