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81.
Raffaele De Vita Delia Cavallo Luigi Raganella Patrizia Eleuteri Maria G. Grollino Alberto Calugi 《Bioelectromagnetics》1995,16(5):330-334
Flow cytometry (FCM) was performed to monitor the cellular effects of extremely-low-frequency magnetic field on mouse spermatogenesis. Groups of five male hybrid F1 mice aged 8–10 weeks were exposed to 50 Hz magnetic field. The strength of the magnetic field was 1.7 mT. Exposure times of 2 and 4 h were chosen. FCM measurements were performed 7, 14, 21, 28, 35, and 42 days after treatment. For each experimental point, a sham-treated group was used as a control. The possible effects were studied by analyzing the DNA content distribution of the different cell types involved in spermatogenesis and using the elongated spermatids as the reference population. The relative frequencies of the various testicular cell types were calculated using specific software. In groups exposed for 2 h, no effects were observed. In groups exposed for 4 h, a statistically significant (P < 0.001) decrease in elongated spermatids was observed at 28 days after treatment. This change suggests a possible cytotoxic and/or cytostatic effect on differentiating spermatogonia. However, further studies are being carried out to investigate the effects of longer exposure times. © 1995 Wiley-Liss, Inc. 相似文献
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Serena Candela Raffaele Dito Barbara Casolla Emanuele Silvestri Giuliano Sette Federico Filippi Maurizio Taurino Domitilla Brancadoro Francesco Orzi 《PloS one》2016,11(4)
BackgroundCEA is associated with peri-operative risk of brain ischemia, due both to emboli production caused by manipulation of the plaque and to potentially noxious reduction of cerebral blood flow by carotid clamping. Mild hypothermia (34–35°C) is probably the most effective approach to protect brain from ischemic insult. It is therefore a substantial hypothesis that hypothermia lowers the risk of ischemic brain damage potentially associated with CEA. Purpose of the study is to test whether systemic endovascular cooling to a target of 34.5–35°C, initiated before and maintained during CEA, is feasible and safe.MethodsThe study was carried out in 7 consecutive patients referred to the Vascular Surgery Unit and judged eligible for CEA. Cooling was initiated 60–90 min before CEA, by endovascular approach (Zoll system). The target temperature was maintained during CEA, followed by passive, controlled rewarming (0.4°C/h). The whole procedure was carried out under anesthesia.ResultsAll the patients enrolled had no adverse events. Two patients exhibited a transient bradycardia (heart rate 30 beats/min). There were no significant differences in the clinical status, laboratory and physiological data measured before and after CEA.ConclusionsSystemic cooling to 34.5–35.0°C, initiated before and maintained during carotid clamping, is feasible and safe.
Trial Registration
ClinicalTrials.gov NCT02629653相似文献84.
85.
In this article we generalize the use of a relationship based on the occurrence of some characteristic temperatures in protein unfolding, which were originally high-lighted for proteins showing the unfolding enthalpy-entropy convergence. On this basis, we show how to dissect the unfolding Gibbs energy of globular proteins in terms of solid-like and liquid-like contributions, untangling the protein energetics by a scheme which does not suffer from excessive intricacy. We also provide an experimental estimate of unfavorable polar contributions to the protein stability, by which it seems possible to evaluate the number of buried residues in individual proteins. A comparison is assessed with the so-called hard sphere model of globular proteins. Results seem to reconcile the view that the protein interior is liquid-like with the observation that protein organization resembles an assembly of closely packed spheres. 相似文献
86.
The aim of this work was the development of extended release tablets of 500 mg of ciprofloxacin based on swellable drug polyelectrolyte
matrices (SDPM). A set of complexes of carbomer, ciprofloxacin and sodium, (CB–Cip)50Na
x
, having a molar ratio Cip/CB acid groups of 0.5 and variable proportions of Na+ was used to prepare SDPM. Characterization of complexes by FT-IR, powder X-ray diffraction and thermal analysis revealed
that Cip, in its protonated form, is ionically bonded to the functional groups of CB. Rates of fluid uptake of (CB–Cip)50Na
x
matrices as well as Cip release in simulated gastric fluid were modulated by changes in the proportion of Na+ incorporated in the complexes. A direct correlation between fluid uptake and delivery rate was observed along the series
of matrices. Release rates were modulated from 1.4 mg/min to 25 mg/min in going from (CB–Cip)50Na10 to (CB–Cip)50Na14. The analysis of kinetic data suggest that rates of swelling, ionic pair dissociation and drug diffusion play a role in the
kinetic control of delivery. Complexes were satisfactorily prepared and processed together with small amounts of antiadherent
and lubricant excipients to obtain a series of extended release SDPM tablets through the current tableting technology processes.
Cip release from matrices was widely modulated by the composition of the complexes yielding a flexible system that allows
selecting a composition that releases in 120 min 90% of the dose in simulated gastric fluid. 相似文献
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Nitrous oxide and methane fluxes from soils of the Orinoco savanna under different land uses 总被引:2,自引:0,他引:2
Castaldi Simona De Pascale Raffaele Ariangelo Grace John† Nikonova Nina§ Montes Ruben§ San José José‡ 《Global Change Biology》2004,10(11):1947-1960
The study investigates the effect of land‐use change on nitrous oxide (N2O) and methane (CH4) fluxes from soil, in savanna ecosystems of the Orinoco region (Venezuela). Gas fluxes were measured by closed static chambers, in the wet and dry season, in representative systems of land management of the region: a cultivated pasture, an herbaceous savanna, a tree savanna and a woodland (control site). Higher N2O emissions were observed in the cultivated pasture and in the herbaceous savanna compared with the tree savanna and the woodland, and differences were mainly related to fine soil particle content and soil volumetric water content measured in the studied sites. Overall N2O emissions were quite low in all sites (0–1.58 mg N2O‐N m?2 day?1). The cultivated pasture and the woodland savanna were on average weak CH4 sinks (?0.05±0.07 and ?0.08±0.05 mg CH4 m?2 day?1, respectively), whereas the herbaceous savanna and the tree savanna showed net CH4 production (0.23±0.05 and 0.19±0.05 mg CH4 m?2 day?1, respectively). Variations of CH4 fluxes were mainly driven by variation of soil water‐filled pore space (WFPS), and a shift from net CH4 consumption to net CH4 production was observed at around 30% WFPS. Overall, the data suggest that conversion of woodland savanna to managed landscape could alter both CH4 and N2O fluxes; however, the magnitude of such variation depends on the soil characteristics and on the type of land management before conversion. 相似文献
90.
Morana A Paris O Maurelli L Rossi M Cannio R 《Extremophiles : life under extreme conditions》2007,11(1):123-132
An open reading frame encoding a putative bi-functional β-d-xylosidase/α-l-arabinosidase (Sso3032) was identified on the genome sequence of Sulfolobus solfataricus P2, the predicted gene product showing high amino-acid sequence similarity to bacterial and eukaryal individual β-d-xylosidases and α-l-arabinosidases as well as bi-functional enzymes such as the protein from Thermoanaerobacter ethanolicus and barley. The sequence was PCR amplified from genomic DNA of S. solfataricus P2 and heterologous gene expression obtained in Escherichia coli, under optimal conditions for overproduction. Specific assays performed at 75°C revealed the presence in the transformed
E. coli cell extracts of this archaeal activity involved in sugar hydrolysis and specific for both substrates. The recombinant protein
was purified by thermal precipitation of the host proteins and ethanol fractionation and other properties, such as high thermal
activity and thermostability could be determined. The protein showed a homo-tetrameric structure with a subunit of molecular
mass of 82.0 kDa which was in perfect agreement with that deduced from the cloned gene. Northern blot analysis of the xarS gene indicates that it is specifically induced by xylan and repressed by monosaccharides like d-glucose and l-arabinose. 相似文献