Biomedical subjects

M Bellafiore

Publications and source records attributed to M Bellafiore.

13 recordsLinked to original sources

PubMed2006

Research of cardiomyocyte precursors in adult rat heart.

Recent reports supported the existence of stem cells in adult hearts. However, phenotype and localization of these cells have not been completely described and it is unknown if cardiac regenerative potential differs from one subject to another. The aims of our work were to identify different populations of cardiac stem cells by the analysis of specific markers and to evaluate the expression variability of these markers in 12 adult rat hearts. The expression of CD9, taube nuss and nanog suggests the presence of stem cells from the earliest stages of embryogenesis in adult myocardium. Their different expression could be associated to the degree of stem cell differentiation. CD34 and c-Kit antibodies were used to detect stem cells committed to one or more specific tissue lineages and we found a strong immunoreactivity for CD34 exclusively in the endothelial cells and a low positivity for c-Kit in the interstitium and next to the vessels. Moreover, as c-Kit expression highly differed within all examined hearts, we suggest that cardiomyogenic potential is different among the various subjects. Undifferentiated cells with myogenic-committed phenotype expressing GATA-4 and nestin were found, respectively, in the interstitial and myocardial cells and in few interstitial cells. Therefore, the physiologic turn over of cardiomyocytes may occur in adult hearts as it has been shown in many others organs. The study of myogenic potential could be important to identify markers specific of stem cells in in vivo adult myocardium that may be used to purify these cells and evaluate their regenerative ability.

Animals↗

PubMed2003

60KDa chaperonin (HSP60) is over-expressed during colorectal carcinogenesis.

The aim of the present study was to evaluate the expression of the heat shock protein 60 (HSP60), a mitochondrial matrix-associated protein belonging to the chaperonin family, in colorectal adenomas and cancers, comparing them to normal colonic tissues and hyperplastic polyps. We performed both immunohistochemistry and Western blot analysis for HSP60. Immunohistochemistry resulted positive in all tubular adenomas and infiltrating adenocarcinomas. By contrast, normal tissues and hyperplastic polyps were negative. Quantitative analysis showed that tubular adenomas with different levels of dysplasia did not present statistical differences concerning HSP60 positivity. In addition, carcinomas always showed the highest expression. Western blot analysis confirmed these observations. These data suggest that HSP60 over-expression is an early event in carcinogenesis. We suspect that HSP60 plays a different role in colorectal carcinogenesis with respect to that in normal cells, which foresees its possible use as diagnostic and prognostic tools.

Adenocarcinoma↗

PubMed2003

Presence of atrial natriuretic factor in normal and hyperplastic human prostate and its relationship with oxytocin localisation.

In this work, we showed the presence of atrial natriuretic factor (ANF) in human prostate and compared its localisation in normal and hyperplastic conditions. ANF was localised in epithelial and stromal cells, being increased in hyperplasia, mainly in the stromal component. Moreover, we compared ANF and oxytocin positivity in the same glands, focusing on the possible relationship between the paracrine effects of these two hormones.

Atrial Natriuretic Factor↗

PubMed2002

Protective role of the complement regulatory protein human CD-55 in cardiac xenograft: a descriptive study and a revision of the literature.

The limited and inadequate availability of organs from human donors has resulted in the utilisation of xenografts as an alternative tool. Nevertheless, hyperacute rejection (HAR) following xenograft determines the loss of the transplanted organ. The "primum movens" is the activation of the complement pathway mediated by the binding of natural xenogenic antibodies to the endothelium of the graft, followed by the lysis of the endothelial cells with subsequent oedema, thrombosis and necrosis of the transplanted organ. In this work we describe morphological and biomolecular observations of isolated human-decay accelerating factor (h-DAF, CD55) transgenic pig hearts, after perfusion for four hours with human blood. H-DAF is a membrane glycoprotein inhibiting the complement activation in humans. We describe considerably reduced damages in transgenic hearts, compared to controls. The cardiac function resulted preserved. Our data are in agreement with what was already shown by other groups using different experimental models. In conclusion, we encourage the use of new sources of transgenic animals, pointing out the importance of morphological analysis in evaluation of xenograft.

Animals↗

PubMed2002

Defective apoptosis and tumorigenesis: role of p53 mutation and Fas/FasL system dysregulation.

The transcription factor p53 and the cytokine receptor FasL are two of the most famous regulators of cell life, and their alterations can cause a large number of pathologies, including cancer. In this review, we focused on how they can determine defective apoptosis, one of the causes of tumorigenesis and tumor progression. The importance of this knowledge lies in the new perspectives that gene therapy can offer to cure cancer.

Animals↗

PubMed2001

Poorly differentiated synovial sarcoma: a case report.

Poorly differentiated synovial sarcoma is a rare soft tissue tumor. We studied a case arising in the pleural cavity of a young subject, characterised by the presence of spindle cell, small cell, and large epithelioid cell areas. We performed stains for mucosubstances and analysed the expression of cytokeratins 5/6, 7, 8, 18, 19, CEA, CD34, Ber-Ep4 and calretinin to characterize the phenotype of this neoplasm. We furthermore assessed immunohistochemically the presence of p53, Bcl-2, Bax and caspase 3, four apoptotic markers, to evaluate a relationship between apoptotic activity and the behaviour of this tumor. Our findings showed a strong presence of calretinin, p53 and Bcl-2 in all three areas. The possibility that poorly differentiated synovial sarcoma could be calretinin-positive was a new data, to our knowledge, and it could be of some importance in diagnostic pathology. Moreover, the negligible positivity for Bax and caspase 3 suggested that the minor role of programmed cell death could be one of the causes of the aggressive behaviour of this tumor. These data also suggest that the reduction of apoptotic phenomena in poorly differentiated synovial sarcoma could be considered one of the major mechanisms of tumoral growth.

Adult↗

PubMed2001

Study of axillary lymph node asymmetry in a female population.

We analysed a large series of axillary lymph nodes, with and without metastases following radical mastectomy for breast cancer. We found left/right asymmetry in numbers of lymph nodes, and also asymmetry of lymph node dimensions, which could have been the caused by tumoral antigenic stimulation. The distribution of hyperplastic node patterns differed significantly.

Adult↗

PubMed2001

The hypothalamic magnocellular neurosecretory system in developing rats.

Studies concerning the development of the magnocellular system are scarce and discordant in literature. We carried out an immunohistochemical study on supraotic and paraventricular hypothalamic nuclei using antivasopressin and antioxytocin antibodies in developing rats between the 15th day of intrauterine life and the 6th day of postnatal life. In addition, we performed RT-PCR experiments to establish the stage at which these hormones appear and neurosecretory activity commences. The results showed that supraoptic and paraventricular nuclei appear, respectively, on the 16th and the 18th day of intrauterine life and both immediately synthetize vasopressin neurohormone. By contrast, synthesis of oxytocin takes place from the 2nd day after birth. Probably, these nuclei synthetize oxytocin in conjunction with the decline of placental maternal oxytocin.

Animals↗

PubMed2000

3'-untranslated regions of oxidative phosphorylation mRNAs function in vivo as enhancers of translation.

Recent findings have indicated that the 3'-untranslated region (3'-UTR) of the mRNA encoding the beta-catalytic subunit of the mitochondrial H(+)-ATP synthase has an in vitro translation-enhancing activity (TEA) [Izquierdo and Cuezva, Mol. Cell. Biol. (1997) 17, 5255-5268; Izquierdo and Cuezva, Biochem. J. (2000) 346, 849-855]. In the present work, we have expressed chimaeric plasmids that encode mRNA variants of green fluorescent protein in normal rat kidney and liver clone 9 cells to determine whether the 3'-UTRs of nuclear-encoded mRNAs involved in the biogenesis of mitochondria have an intrinsic TEA. TEA is found in the 3'-UTR of the mRNAs encoding the alpha- and beta-subunits of the rat H(+)-ATP synthase complex, as well as in subunit IV of cytochrome c oxidase. No TEA is present in the 3'-UTR of the somatic mRNA encoding rat mitochondrial transcription factor A. Interestingly, the TEA of the 3'-UTR of mRNAs of oxidative phosphorylation is different, depending upon the cell type analysed. These data provide the first in vivo evidence of a novel cell-specific mechanism for the control of the translation of mRNAs required in mitochondrial function.

3' Untranslated Regions↗

PubMed2000

Specific neurons of brain cortex and cerebellum are PIPPin positive.

We recently cloned a cDNA encoding an RNA-binding protein, that we called PIPPin, which is highly enriched in the rat brain and contains two putative double stranded RNA-binding domains (PIP1 and PIP2) and a central cold shock domain (CSD). Here we report that PIPPin is specifically enriched in some pyramidal neurons of the cerebral cortex and in the Purkinje cells of the cerebellum. We also show that PIPPin inhibits translation of H1(o) and H3.3 mRNA in a cell-free system. The results reported suggest that PIPPin down-regulates histone variant expression in the developing rat brain.

Animals↗

PubMed1999

PIPPin is a brain-specific protein that contains a cold-shock domain and binds specifically to H1 degrees and H3.3 mRNAs.

During maturation of mammalian brain, variants of both linker (i.e. H1 degrees) and core (i.e. H3.3) histone proteins accumulate in nerve cells. As the concentration of the corresponding transcripts decreases, in postmitotic cells, even if the genes are actively transcribed, it is likely that regulation of variant histone expression has relevant post-transcriptional components and that cellular factors affect histone mRNA stability and/or translation. Here we report that PIPPin, a protein that is highly enriched in the rat brain and contains a cold-shock domain, binds with high specificity to the transcripts that encode H1 degrees and H3.3 histone variants. Both mRNAs are bound through the very end of their 3'-untranslated region that encompasses the polyadenylation signal. Although PIPPin is present both in the cytoplasm and the nucleus of nerve cells, PIPPin-RNA complexes can be obtained only from nuclear extracts. The results of two-dimensional electrophoretic analysis suggest that a relevant proportion of nuclear PIPPin is more acidic than expected, thus suggesting that its RNA binding activity might be modulated by post-translational modifications, such as phosphorylation.

3' Untranslated Regions↗

PubMed1998

H1(0) RNA-binding proteins specifically expressed in the rat brain.

During brain maturation, histone H1(0) accumulates in both nerve and glial cells. The expression of this "linker" histone, the role of which still remains unclear, is a complex process, having both transcriptional and post-transcriptional regulatory components. In particular, the expression of H1(0) in rat cortical neurons is regulated mainly at the post-transcriptional level, and unknown cellular proteins are likely to affect H1(0) mRNA stability and/or translation. In looking for such factors, we tested the ability of rat brain extracts to protect H1(0) RNA probe from degradation by T1 RNase. The results reported here demonstrate that rat brain contains at least one major (p40) and two minor (p110 and p70) binding factors, specific for H1(0) RNA, all of which are much more or exclusively expressed in adult rat brain, when compared with other tissues. The binding of the factors is confined to a portion of the 3'-untranslated region (3'-UTR), which is highly conserved among murine and human H1(0) mRNAs. These findings suggest that the proteins identified play a critical role in regulating the expression of H1(0) histone in the brain of mammals.

Animals↗

PubMedDate not supplied

Expression of 60-kD heat shock protein increases during carcinogenesis in the uterine exocervix.

OBJECTIVES: The aim of the present study was to determine the presence and expression of the 60-kD heat shock protein (HSP60) in the dysplasia-carcinoma sequence in the uterine exocervix and to evaluate its diagnostic and prognostic significance. METHODS AND RESULTS: We performed Western blot and immunohistochemical analyses on biopsies from 40 cases, consisting of 10 normal exocervical biopsies, 10 low-grade squamous intraepithelial lesions (L-SIL), 10 high-grade squamous intraepithelial lesions (H-SIL) and 10 cancerous exocervices (G2 grade). The immunohistochemical results were quantified by computer-assisted image analysis. Western blot analysis showed that HSP60 was undetectable in normal tissues and that there was a gradual increase of protein expression from L-SIL to carcinoma. Immunostaining for HSP60 was negative in normal tissue and positive in basal and parabasal layers of L-SIL epithelium; H-SIL were markedly stained in all layers of epithelium, and carcinomas showed an even stronger positivity. The increasing expression correlated with the malignancy grade. Finally, koilocytes were mostly negative in L-SIL and positive in H-SIL. CONCLUSIONS: The increasing degree of expression of HSP60 from L-SIL to carcinoma and the different intraepithelial distribution between L-SIL and H-SIL could be used as a new diagnostic tool. Moreover, HSP60 could have a role in cervical carcinogenesis.

Blotting, Western↗