1,720,971 research outputs found
Modulazione del ciclo del citrato nei mitocondri degli oociti di Xenopus laevis e bioritmi 1. Caratteristiche di mitocondri "olocoerenti"
No full textAnalisi pre-restauro e conservazione di reperti lignei dell’imbarcazione romana rinvenuta presso la baia di Scauri (Pantelleria)
No full textIl volume, oltre ad essere un compendio tecnico-scientifico, illustra la sintesi dell’imponente e significativo lavoro svolto dalle strutture competenti e dagli specialisti che si sono succeduti nell’ultimo decennio nello scavo archeologico subacqueo del relitto tardo-antico di Scauri a Pantelleria. In particolare il contributo si occupa delle analisi pre-restauro effettuate su elementi o parti strutturali pertinenti all'imbarcazione stessa per individuare lo stato di degrado del legno e la conseguente metodologia di restauro da utilizzare
Recommending salt intake reduction to the hypertensive patient: More than just lip service
No full textThe average individual dietary salt intake largely exceeds the physiological needs almost worldwide. A direct causal association between salt intake and blood pressure levels has been clearly established. Furthermore, there is increasing evidence for additional blood pressure-independent pathways linking excess salt intake to the process of atherosclerosis. Recent meta-analyses of randomized controlled trials showed that moderate reduction of salt intake is associated with reduction of blood pressure and, in perspective, with reduction of cardiovascular and cerebrovascular events in hypertensive individuals. According to the European Society of HypertensionEuropean Society of Cardiology (ESHESC) guidelines for the management of hypertension, instructions to reduce dietary salt intake to the level of 5gday based on the WHO recommendation should be provided to all patients, regardless of their requirement for drug treatment. Unfortunately, the patients response to this measure is heterogeneous, mainly due to variable compliance with the doctors prescription and to a lesser extent to different individual BP salt sensitivity.This article discusses the factors affecting the probability of a successful intervention focusing in particular on the doctors commitment to evaluate the patients dietary habits, to point out the main sources of salt in the patients diet, to provide the patient with adequate motivation and with proper instructions to implement gradual reduction of hisher salt intake, not disregarding the need for regular follow-up
Metodiche non invasive per la valutazione del danno ossidativo in ovociti di mammifero: possibili applicazioni della Spettroscopia Raman
No full textPossible role for Ca(2+) calmodulin-dependent protein kinase II as an effector of the fertilization Ca(2+) signal in mouse oocyte activation
No full textThe present study shows that Ca(2+) calmodulin-dependent protein kinase II (CaM kinase II) is physiologically activated in fertilized mouse oocytes and is involved in the Ca(2+) response pathways that link the fertilization Ca(2+) signal to meiosis resumption and cortical granule (CG) exocytosis. After 10 min of insemination, CaM kinase II activity increased transiently, then peaked at 1 h and remained elevated 30 min later when most of the oocytes had completed the emission of the second polar body. In contrast, in ethanol-activated oocytes the early transient activation of CaM kinase II in response to a monotonic Ca(2+) rise was not followed by any subsequent increase. Inhibition of CaM kinase II by 20 micromol/l myristoylated-AIP (autocamtide-2-related inhibitory peptide) negatively affected MPF (maturing promoting factor) inactivation, cell cycle resumption and CG exocytosis in both fertilized and ethanol-activated oocytes. These results indicate that the activation of CaM kinase II in mouse oocytes is differently modulated by a monotonic or repetitive Ca(2+) rise and that it is essential for triggering regular oocyte activation
Metodiche non invasive per la valutazione del danno ossidativo in ovociti di mammifero: possibili applicazioni della spetroscopia Raman
No full textOral possibile role of carbonyl stress in ovarian aging
No full textIntroduction: Female reproductive aging has been so far deeply characterized
in terms of ovarian functional decline associated with gradual depletion of
ovarian follicles and reduced oocyte developmental potential [1,2]. However
little is known about molecular mechanism underlying age-related cellular
modifications. Similarly to somatic aging, the most relevant theory for
ovarian aging implies a reduced ability of ovarian follicles to counteract reactive
oxygen species (ROS), which are among the most important physiological
inducers of cellular injury [3,4]. Also, molecular damage during somatic aging
has been ascribed to increased levels of reactive dicarbonyl compounds, which,
similarly to ROS, result from normal metabolism but can be responsible for
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Abstracts of the 23rd Annual Meeting of the ESHRE, Lyon, France, 1–4 July 2007
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macromolecular damage [5]. In the present study we investigated the hypothesis
that aging-associated changes in the ovarian follicles may involve a condition
of “carbonyl stess” due to impaired degradation of cytotoxic
dicarbonyl compounds such as methylglyoxal (MG), one of the most powerful
glycating agents of cellular components [6]. To this end, first we monitored in
the mouse model MG cytotoxic effects on the oocyte and characterized in the
ovary the system mainly involved in MG degradation, the glyoxalase system,
which consists of two enzymes, glyoxalase I (GLOI) and glyoxalase II
(GLOII). Second, we evaluated possible changes in this system in relation to
reproductive aging.
Materials and methods: The study was conducted on CD1 young (4–8 wk
old) and old (48–52 wk old) female mice. MG toxicity was evaluated by monitoring
oocyte chromosome configuration by Hoechst33342 staining and DNA
fragmentation by TUNEL assay following exposure to different MG concentrations
(50-300 micromolar) during in vitro maturation. Enzymatic activity
of GLOI and GLOII enzymes was measured spectrophotometrically in whole
ovaries. Expression of GLOI and GLOII mRNA was analyzed by means of
semi-quantitative RT-PCR in (1) whole ovaries, denuded oocytes from (2)
early antral (DO) or (3) preovulatory follicles (CEO) and (4) oocytes at MII
stage.
Results: Exposure of young oocytes MG was responsible for a dose-dependent
delay in the kinetic of meiosis resumption, aberrant MII configuration and
apoptosis. Specific activity of GLOI measured in whole ovaries from young
mice was similar to that present in proliferating tissues, whereas that of
GLOII was not detectable. The analysis of gene expression pattern revealed
that: 1) GLOII mRNAs were expressed in the ovaries although at levels
lower that those of GLOI; 2) in MII oocytes the levels of transcripts for both
the enzymes severely reduced when compared with DO and CEO. From the
comparison of this pattern of expression with that of old mice we observed
that the activity of GLOI and the level of the corresponding mRNA were significantly
lowered in old ovaries. Although age-related changes in GLOI and
GLOII gene expression were not detectable, old oocytes compared with
young oocytes were more sensitive to methylglyoxal, being their maturation
severely compromised by the exposure to this compound.
Conclusions: Presents results provide evidence that ovarian aging may be
associated with the impairment of detoxifying processes of reactive dycarbonyl
compounds toxic for the mammalian oocyte suggesting that this condition may
jeopardize the development of competent gametes during reproductive agin
Age-associated changes in mouse oocytes during postovulatory in vitro culture: possible role for meiotic kinases and survival factor BCL2
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