Biomedical subjects

C Cecchi

Publications and source records attributed to C Cecchi.

At least 19 recordsLinked to original sources

PubMed2006

Protective effects of the PARP-1 inhibitor PJ34 in hypoxic-reoxygenated cardiomyoblasts.

To clarify the role of poly(ADP-ribose)polymerase-1 (PARP-1) in myocardial ischemia-reperfusion injury, we explored some effects of PJ34, a highly specific inhibitor of this enzyme, in hypoxic-reoxygenated (HR) H9c2 cardiomyoblasts. Compared to the control, HR cells showed signs of oxidative stress, marked PARP-1 activation, NAD(+) and ATP depletion and impaired mitochondrial activity. HR cardiomyoblasts were affected by both necrosis and apoptosis, the latter involving the nuclear translocation of apoptosis-inducing factor. In HR cardiomyoblasts treated with PJ34, oxidative stress and PARP-1 activity were decreased, and NAD(+) and ATP depletion, as well as mitochondrial impairment, were attenuated. Above all, PJ34 treatment improved the survival of HR cells; not only was necrosis significantly diminished, but apoptosis was also reduced and shifted from a caspase-independent to a caspase-dependent pathway. These results suggest that PARP-1 modulation by a selective inhibitor such as PJ34 may represent a promising approach to limit myocardial damage due to post-ischemic reperfusion.

Adenosine Triphosphate↗

PubMed2005

Absorbed dose rate estimation for protons, leptons and helium observed with AMS01 experiment in low earth orbit during STS-91 mission.

The Alpha Magnetic Spectrometer (AMS01), a high-sensitivity particle spectrometer, was successfully flown for 10 d in June 1998 (STS91) in the orbit of the International Space Station (51.7 degrees, -380 km). A high-statistics dataset of galactic cosmic rays were measured as a function of geomagnetic latitude, including the primary protons, leptons and helium as well as the trapped and quasi-trapped proton and lepton components. In this paper, the absorbed dose rate owing to the protons, leptons and helium are presented and compared with measurements made by other instruments flown on the same mission.

Body Burden↗

PubMed2004

Acylphosphatase overexpression triggers SH-SY5Y differentiation towards neuronal phenotype.

An acylphosphatase (AcPase) overexpression study was carried out on SH-SY5Y neuroblastoma cells, using a green fluorescent fusion protein (AcP-GFP), with GFP acting as a reporter protein. The cellular proliferation rate was significantly reduced by overexpression of AcPase by a factor of ten. In contrast, clones transfected with two inactive AcPase mutants showed a growth rate comparable to control cells. This suggests that AcPase catalyzes the proliferative down-regulation. AcPase-overexpressing clones showed a physiological mortality rate as assessed by an MTT reduction test and by evaluation of necrotic markers. DNA fragmentation analysis and assays of caspase-3 and poly (ADP-ribose) polymerase (PARP)-active fragments showed no evidence of any apoptotic pattern. AcPase overexpression led to a marked increase in PARP activity as well as Bcl-2 content; these are commonly up-regulated during differentiative processes in neuronal cells. In fact, the typical differentiation marker, growth-associated-protein 43, was significantly up-regulated. Microscopic observations also showed a clear increase in the differentiative phenotype in AcPase-overexpressing cells. Our results clearly show that AcPase plays a primary causative role in neuronal differentiation.

Acid Anhydride Hydrolases↗

PubMed2002

Biochemical changes and their relationship with morphological and functional findings in pig heart subjected to lasting volume overload: a possible role of acylphosphatase in the regulation of sarcoplasmic reticulum calcium pump.

We evaluated the changes in sarcoplasmic reticulum (SR) function and the parallel hemodynamic and morphological modifications in a heart subjected to volume overload. We also determined the levels of acylphosphatase, a cytosolic enzyme, that could play a regulatory effect on SR Ca(2+) pump by hydrolyzing the phosphorylated intermediate of this transport system. For this, swine hearts were subjected to volume overload by aorta-cava shunt for 1, 2, or 3 months. Changes in heart contractility reflected modifications of SR function, whose reduction after 1 month of overload was followed by a gradual recovery. A decrease in SERCA2a protein and mRNA content was shown from 1 month and remained for the following 2 months. Phospholamban content and its phosphorylation status were not modified. Acylphosphatase was unchanged at 1 month, but at 2 months this enzyme exhibited an increased activity, protein and mRNA expression. Morphological alterations consisting of the cytoskeletal architectures, intermyofibrillar oedema, swollen mitochondria and abnormality of the membrane system (T-tubule and SR cisternae) were particularly evident after 1 month but almost disappeared after 3 months. These results suggest that our overloaded hearts underwent a substantial recovery of their structural and biochemical properties at 3 months after surgery. A possible involvement of acylphosphatase in the modification of SR function is discussed.

Acid Anhydride Hydrolases↗

PubMed2000

Lack of SOD1 gene mutations and activity alterations in two Italian families with amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a progressive fatal disorder, which results from the degeneration of motor neurons in the brain and spinal cord. Approximately 20% of the inherited autosomal dominant cases are due to mutations within the gene coding for Cu/Zn superoxide dismutase 1 (SOD1), a cytosolic homodimeric enzyme that catalyzes the dismutation of toxic superoxide anion. We investigated the presence of SOD1 gene mutations and activity alterations in two unrelated families of ALS patients from Elba, an island of central Italy. No mutation in SOD1 exon 1 to 5 and no activity alteration were observed in all members of the two analyzed ALS families (FALS). These data show an apparent heterogeneous distribution of ALS patients with SOD1 gene mutations among different populations and suggest that another genetic locus could be involved in the disease.

Amyotrophic Lateral Sclerosis↗

PubMed2000

The lack of Emx2 causes impairment of Reelin signaling and defects of neuronal migration in the developing cerebral cortex.

Neocorticogenesis in mice homozygous for an Emx2 null allele is the topic of this article. The development of both main components of neocortex, primordial plexiform layer derivatives and cortical plate, was analyzed, paying special attention to radial migration of neurons forming the cortical plate. The products of the Reelin gene, normally playing a key role in orchestrating radial migration of these neurons, display normal distribution at the beginning of the cortical neuronogenesis but are absent in the neocortical marginal zone of the mutant mice at the time when the cortical plate is laid down. As a consequence, the development of radial glia is impaired, and neurons making up the cortical plate display abnormal migration patterns. In addition, restricted defects along the rostrocaudal and the mediolateral axes are present in the subplate, suggesting an Emx2-specific role in priming the proper development of this layer.

Animals↗

PubMed2000

Early changes induced in the left ventricle by pressure overload. An experimental study on swine heart.

The purpose of this study was to evaluate the early changes in sarcoplasmic reticulum (SR) function and the parallel morphological and hemodynamic modifications occurring in the heart following pressure overload. As regards SR function, we also explored the levels of acylphosphatase, an enzyme which might have a regulatory effect on the SR Ca(2+) pump by hydrolyzing the phosphorylated intermediate of this transport system. Pigs subjected to pressure overload by aortic stenosis for 6, 12, 24, 48, 72, and 96 h were compared to sham-operated controls. At each of the considered times both SR Ca(2+)-ATPase activity and Ca(2+) uptake, as well as acylphosphatase activity, were significantly enhanced in the pressure overloaded compared to the control hearts, with a maximal increase at 6 h; moreover, a positive and significant correlation was found between these parameters. The modifications in the activities of Ca(2+)-ATPase and acylphosphatase reflected an increased expression of these proteins, while phospholamban did not show significant changes in its concentration nor in its phosphorylation status. As for hemodynamic parameters, rapid changes in the left ventricular function were observed and especially the early hours following the aortic stenosis appeared to be crucial for the adjustment of heart function. The most relevant morphological finding was a focal disarrangement of the myofibrillar pattern which was very evident at 6 h, and progressively attenuated at later times. Taken together our data suggest that an early adaptation to the increased hemodynamic working overload is a consistent activation of the contractile apparatus which reflects, at least in part, an enhanced SR function. Besides the changes in Ca(2+) pump protein expression, increased acylphosphatase levels might also contribute to this effect.

Animals↗

PubMed2000

Emx homeogenes and mouse brain development.

Mammalian homeogenes of the Emx family, Emx1 and Emx2, are expressed in the developing cerebral cortex and are involved in the patterning of the rostral brain. Although very little is known about the role of Emx1, details of the function of EMX2 are emerging from the observation of cortical phenotypes in normal and mutant mice. Emx2 is expressed in proliferating neuroblasts and in the so-called postmitotic Cajal-Retzius cells, known to control migration of cortical neurons. The graded distribution of EMX2 homeoprotein suggests a potential role for Emx2 in the subdivision of the cortex into territories and possibly areas.

Animals↗

PubMed2000

Epidemiology of social phobia: a clinical approach.

The recent epidemiologic studies report extremely varied rates for social phobia (SP). One of the reasons for this may be the difficulty in diagnosing SP, the boundaries of which are uncertain. A community survey was carried out using doctors with experience in clinical psychiatry as interviewers, and a clinical diagnostic instrument. Two thousand three hundred and fifty-five people (out of the 2,500 randomly selected from the population) living in Sesto Fiorentino, a suburb of Florence, Italy, were interviewed by their own general practitioner, using the MINI plus six additional questions. Six hundred and ten of the 623 subjects that were found positive for any form of psychopathology at the screening interview, and 57 negative subjects, were re-interviewed by residents in psychiatry using the Florence Psychiatric Interview (FPI). The FPI is a validated composite instrument that has the format of a structured clinical research record. It was found that 6.58% of subjects showed social anxiety not attributable to other psychiatric or medical conditions during their life. Social or occupational impairments meeting DSM-IV diagnostic requirements for SP was detected in 76 subjects (lifetime prevalence = 3.27%). Correction for age raises the lifetime expected prevalence to 4%. Sex ratio was approximately (F:M) 2:1. The most common fear was speaking in public (89.4%), followed by entering a room occupied by others (63.1%) and meeting with strangers (47.3%). Eighty-six point nine percent of subjects with SP complained of more than one fear. The mean age of onset (when the subjects first fully met DSM-IV criteria for SP) was 28.8 years, but the first symptoms of SP usually occurred much earlier, with a mean age of onset at 15.5 years. Ninety-two percent of cases with SP also showed at least one other co-morbid psychiatric disorder during their life. Lifetime prevalence of avoidant personality disorder (APD) was 3.6%. Forty-two point nine percent of cases with SP also had APD, whereas 37.9% of cases with APD developed SP.

Adolescent↗

PubMed2000

Interaction between acylphosphatase and SERCA in SH-SY5Y cells.

Ca2+ transport by sarco/endoplasmic reticulum, tightly coupled with the enzymatic activity of Ca2+ -dependent ATPase, controls the cell cycle through the regulation of genes operating in the critical G, to S checkpoint. Experimental studies demonstrated that acylphosphatase actively hydrolyses the phosphorylated intermediate of sarco/endoplasmic reticulum calcium ATPase (SERCA) and therefore enhances the activity of Ca2+ pump. In this study we found that SH-SY5Y neuroblastoma cell division was blocked by entry into a quiescent G0-like state by thapsigargin, a high specific SERCA inhibitor, highlighting the regulatory role of SERCA in cell cycle progression. Addition of physiological amounts of acylphosphatase to SY5Y membranes resulted in a significant increase in the rate of ATP hydrolysis of SERCA. In synchronized cells a concomitant variation of the level of acylphosphatase isoenzymes opposite to that of intracellular free calcium during the G1 and S phases occurs. Particularly, during G1 phase progression the isoenzymes content declined steadily and hit the lowest level after 6 h from G0 to G1 transition with a concomitant significant increase of calcium levels. No changes in free calcium and acylphosphatase levels upon thapsigargin inhibition were observed. Moreover, a specific binding between acylphosphatase and SERCA was demonstrated. No significant change in SERCA-2 expression was found. These findings suggest that the hydrolytic activity of acylphosphatase increase the turnover of the phosphoenzyme intermediate with the consequences of an enhanced efficiency of calcium transport across endoplasmic reticulum and a subsequent decrease in cytoplasmic calcium levels. A hypothesis about the modulation of SERCA activity by acylphosphatase during cell cycle in SY5Y cells in discussed.

Acid Anhydride Hydrolases↗

PubMed2000

Otx and Emx homeobox genes in brain development.

Over the last few years great progress has been made in the understanding of the formation and regionalisation of the mouse brain. In this review we will focus our attention on two families of homeobox-containing genes essentially coding for four transcription factors involved in brain and forebrain development: the two Emx and the two Otx genes. Here we describe the expression pattern of these genes in the developing mouse, as well as the characterisation of the corresponding knockout mice with special emphasis on Emx2. Whereas Otx genes are clearly involved in the formation and regionalisation of the whole rostral brain, comprised of forebrain and midbrain, our data suggest a role for Emx2 in the specification of the cytoarchitecture of the cerebral cortex, achieved through the control of proliferation of neuronal precursors and of migration of newly-formed neurons to their final destination.

Animals↗

PubMed1999

Gluthatione level is altered in lymphoblasts from patients with familial Alzheimer's disease.

Intracellular levels of glutathione (GSH), glutathione disulphide (GSSG), glutamic acid and gamma-glutamyl cysteine synthetase (gamma-GCS) were measured in lymphoblast lines from patients with familial and sporadic Alzheimer's disease (AD) and from age-matched controls. Lymphoblasts carrying presenilins (PS) and amyloid precursor protein (APP) genes mutations showed significantly decreased GSH content with respect to controls. Levels of GSSG and glutamic acid, as well as the activity of gamma-GCS were not significantly different in lymphoblasts carrying genes mutations as compared with control cells. These results indicate that even peripheral cells not involved in the neurodegenerative process of AD show altered GSH content when carrying PS and APP genes mutations. The provided data appear to be in accordance with the known alteration of GSH levels in central nervous system and strengthen the hypothesis of oxidative stress as an important, possibly crucial mechanism in the pathogenesis of AD.

Alzheimer Disease↗

PubMed1999

Mouse forebrain development. The role of Emx2 homeobox gene.

Over the last few years great progress has been made in the understanding of the formation of the mouse forebrain. Among the genes involved in this process, the mouse Emx homeobox genes Emx1 and particularly Emx2 play a primary role. Here we describe the mRNA and protein expression related to Emx2 in the developing mouse telencephalon, as well as the results obtained studying the corresponding knock-out mice. Our findings indicate a role for this gene in the specification of the forebrain via the control of cell proliferation, as well as in guiding neuronal migration during development through the cortical plate. These studies will hopefully enable us to better understand the molecular mechanisms underlying the formation of the mouse cerebral cortex as well as to establish relevant interactions between the various proteins present in this region of the brain.

Animals↗

PubMed1998

Drosophila melanogaster acylphosphatase: a common ancestor for acylphosphatase isoenzymes of vertebrate species.

An open reading frame encoding a putative acylphosphatase was found in Drosophila melanogaster. The corresponding gene product shows 40% identity and 22 additional amino acid residues at the C-terminus as compared to muscle- and common-type human acylphosphatases. Moreover, all the residues involved in the catalytic mechanism of vertebrate enzymes are conserved in the D. melanogaster acylphosphatase. The D. melanogaster protein and a deletion mutant, similar in length to vertebrate acylphosphatases, were produced by cloning the corresponding cDNA in Escherichia coli. The wild-type enzyme is a protein with a well-established three-dimensional fold and a markedly reduced conformational stability as compared to vertebrate isoenzymes. The specific activity of the enzyme is significantly lower than that found in vertebrate enzymes though the substrate binding capability is basically unaltered. The deletion of 22 residues does not cause a significant change in k(cat), while affecting the apparent binding parameters. This work suggests that the genes encoding the vertebrate enzymes originate from an ancestor gene by duplication and subsequent evolution.

Acid Anhydride Hydrolases↗

PubMed1998

A peptide fraction from factor VIII reduces PKC activity in cultured endothelial cells.

A peptide fraction of low molecular weight (Vueffe) prepared from bovine Factor VIII by enzymatic hydrolysis with trypsin, reduces significantly (p<0.05) membrane bound protein kinase C (PKC) activity in cultured bovine pulmonary artery endothelial cells grown with enhanced glucose levels (22.2 mM) or stimulated by phorbol 12-myristate 13-acetate (PMA). The activation of PKC is a common pathway by which mediators increase transendothelial permeability during tissue inflammation and in the development of diabetic vascular complications. Our results suggest that the antihaemorrhagic properties of Vueffe could be related to a decrease in endothelial permeability mediated by PKC.

Animals↗

PubMed1998

Molecular correlates of the murine Xce locus.

The murine Xce locus, first identified by Bruce Cattanach, influences the primary choice of the X chromosome to be inactivated. Methylation of a GC-rich region (DXPas34) that includes multiple 34 bp repeats and lies some 15 kb 3' to Xist has been shown to vary with Xce haplotype. The degree of methylation on the active X chromosome at this locus represents one of the few molecular correlates of Xce action currently available. Data relating to the specificity and other characteristics of this association are presented.

Animals↗

PubMed1997

Alteration of free calcium levels and acylphosphatase muscular isoenzyme in cultured dystrophic skin fibroblasts.

Levels of free intracellular calcium have been measured on two cell lines of cultured human fibroblasts carrying the genetic lesions occurring in Duchenne and Becker dystrophies. Both cell lines elicited a markedly higher content of the cation (98 nM and 57 nM, respectively) than control fibroblasts (35 nM). Differences toward controls were statistically significant (p < 0.01). Dystrophic fibroblasts were also found to possess a significantly reduced amount by about 50% of muscular acylphosphatase isoenzyme as compared to normal cells. As acylphosphatase was demonstrated to be involved in the regulation of Ca2+-ATPase activity from different sources, a hypothesis was formulated that could explain the disruption of calcium homeostasis as an effect of the altered acylphosphatase activity.

Acid Anhydride Hydrolases↗

PubMed1997

Alteration of intracellular free calcium and acylphosphatase levels in differentiating SH-SY5Y neuroblastoma cells.

Levels of acylphosphatase isoenzymes and free intracellular calcium have been investigated in cultured SH-SY5Y human neuroblastoma cells under stimulation with all-trans retinoic acid and phorbol-12-myristate-13-acetate. Under these conditions morphological and functional characteristics demonstrated the differentiation of SH-SY5Y cells towards neuronal phenotype. Retinoic acid treatment caused a progressive and synchronous increase of the organ common-type acylphosphatase and of free intracellular calcium but not of the muscle-type acylphosphatase. Phorbol-12-myristate-13-acetate treatment gave rise to a peak of the muscle-type acylphosphatase levels during the early differentiation stage whereas organ common-type isoenzyme and free calcium levels show a pattern similar to that observed in retinoic acid-treated cells. These evidences indicate that the two acylphosphatase isoenzymes play different roles in SH-SY5Y differentiation and that during this process the expression of organ common-type acylphosphatase increases in a synchronous way with intracellular free calcium concentration.

Acid Anhydride Hydrolases↗