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Biomedical subjects

A Giordano

Publications and source records attributed to A Giordano.

At least 73 records · Page 4Linked to original sources
PubMed2002

[Alcohol treatment of hydatid cyst in a case of old hydatidosis with hepatic skip].

Hydatidosis is related to parasitical etiology, linked to Echinococcus granulosis and Echinococcus multilocularis. The authors describe an uncommon clinical case of old hydatidosis in an 80-year old woman, presenting hepatic skip , with localization to the right lung and kidney and burrowing to the posterior abdominal wall. Because of the patient's lack of compliance, percutaneous treatment with alcohol of the lumbar lesion with 95% ethanol is carried out under echographic guide, to improve quoad valetudinem prognosis. The authors indicate that the method target are: 1) multiple relapse lesions; 2) complicated anatomie area; 3) multiltle cyst; 4) marginal lesions. Moreover, this method shows important advantages such as be possibility of repetition, low invasivity, high patient's compliance, low rate of shock and dissemination and finally low cost.

Aged↗
PubMed2002

[Telecardiology: a new way to manage the relation between hospital and primary care].

In medicine, computer-applied technology enables the performance of many diagnostic investigations with their transfer to a receiving station for referral. The use of telemedicine appears particularly promising in cardiovascular disease, because the cost/effectiveness ratio of an early, tailored intervention, in terms of life-saving and functional recovery, is demonstrated. The development of telemedicine represents an advantage for the individual patient in terms of the interaction between primary and secondary care. In addition, general practitioners can gain educationally and so be equipped to handle more advanced medical problems, thus reducing the number of hospital follow-up appointments. Economic savings for the health service are a driving force. Evidence to date is that the patient seems satisfied and the general practitioner gains competence, but the extent to which telemedicine results in reduced follow-up appointments and economic savings is not yet established. The findings of studies, even if preliminary, have important implications for the design and implementation of the telemedicine service center within the health care system. Selection of patients, significant service reorganization and provision of logistic support for the setting up and functioning of the telemedicine center will be required for it to operate efficiently. Future research in this subject needs to be more scientifically organized, in order to achieve informed decisions about the appropriate use of this technology.

Cardiovascular Diseases↗
PubMed2002

[Spinal cord electric stimulation. Treatment of serious chronic ischemic syndromes of the limbs].

BACKGROUND: Aim of this study is to estimate the effectiveness of epidural electric stimulation of spinal cord for the treatment of patients with severe peripheral chronic arteriopathy who can't be surgically treated or when surgical therapy failed. METHODS: A retrospective study was carried out on 18 patients with peripheral chronic arteriopathy at clinical stage I of Fontaine classification; average age was of 60.08 years an they had rest pain and dystrophic lesions. Five patients couldn't be surgically treated. Stimulator catheter was placed in the epidural space and its action was evaluated studying lesion demarcation and pain resolution. RESULTS: In 16 cases there was a good pain control and in 14 patients lesion demarcation, while in 4 cases there was cases no improvement and amputation was necessary. CONCLUSIONS: Epidural electric stimulation of spinal cord is a valid treatment in selected patients for ischemia pain control and limb savage.

Chronic Disease↗
PubMed2001

RB2/p130 ectopic gene expression in neuroblastoma stem cells: evidence of cell-fate restriction and induction of differentiation.

The activity of the RB2/p130 gene, which is a member of the retinoblastoma gene family, is cell-cycle-regulated and plays a key role in growth inhibition and differentiation. We used neuroblastoma cell lines as a model for studies on neural crest progenitor cell differentiation. We show that Rb2/p130 ectopic protein expression induces morphological and molecular modifications, promoting differentiation of intermediate (I) phenotype SK-N-BE(2)-C neuroblastoma cells towards a neuroblastic (N) rather than a Schwann/glial/melanocytic (S) phenotype. These modifications are stable as they persist even after treatment with an S-phenotype inducer. Rb2/p130 ectopic expression also induces a more differentiated phenotype in N-type SH-SY-5Y cells. Further, this function appears to be independent of cell-cycle withdrawal. The data reported suggest that the Rb2/p130 protein is able to induce neuronal lineage specification and differentiation in neural crest stem and committed neuroblastoma cells, respectively. Thus, the Rb2/p130 protein seems to be required throughout the full neural maturation process.

Blood Proteins↗
PubMed2001

Functional interaction between cyclin T1/cdk9 and Puralpha determines the level of TNFalpha promoter activation by Tat in glial cells.

In addition to its stimulatory effect on transcription of the HIV-1 LTR, the early protein of HIV-1, Tat, exhibits detrimental effects on the CNS by deregulating the expression of several cytokines and immunomodulators including TNFalpha. Activation of the viral promoter by Tat requires several cellular proteins including cyclin T1 and its partner, cdk9, which upon association with the TAR sequence of the LTR, forms a complex that enhances the activity of RNA polymerase II. Here, we examined the involvement of cyclin T1/cdk9 in Tat-mediated transcriptional activation of the TNFalpha promoter which has no TAR sequence. Results from transfection of human astrocytic cells revealed that both cyclin T1 and cdk9 stimulate the basal promoter activity of TNFalpha, although the level of such activation is decreased in the presence of Tat. Ectopic expression of Puralpha, a brain-derived regulatory protein which binds to Tat, enhanced the basal level of TNFalpha transcription, yet exerted a negative effect on the level of Tat activation of the TNFalpha promoter. The antagonistic effect of Puralpha and Tat upon the TNFalpha promoter was diminished in the presence of cyclin T1 and cdk9, suggesting cooperativity of Puralpha with cyclin T1 and cdk9 in Tat activation of the TNFalpha promoter. Results from protein-protein binding studies showed the interaction of Puralpha with both cyclin T1 and cdk9 through distinct domains of Puralpha which are in juxtaposition with each other. Interestingly, the site for cyclin T1 binding within Puralpha is adjacent to the region which is important for Tat/Puralpha association. In light of these observations, we propose a model which ascribes a bridging role for Puralpha in assembling Tat, cyclin T1, and cdk9 around the promoter region of TAR-negative genes such as TNFalpha, which is responsive to Tat activation.

Astrocytes↗
PubMed2001

Cell cycle genes as targets of retinoid induced ovarian tumor cell growth suppression.

We have examined the effect of all-trans-retinoic acid (RA) on cell cycle gene expression in RA sensitive CA-OV3 and RA resistant SK-OV3 ovarian carcinoma cell lines. Gene expression was analysed by multiprobe RNAse protection, Western blotting and in vitro kinase assays. No differences were observed between RA sensitive and RA resistant ovarian carcinoma cells in the levels of expression of many cell cycle genes including cyclin A, B and E, cdk 2,4 and 6, E2F-1, E2F-2, E2F-3, E2F-4, E2F-5, DP-1 and DP-2. However, RA sensitive CA-OV3 cells expressed higher levels of p53, p27, p21, and p16 compared to RA resistant SK-OV3 cells. In addition, RA treatment of CA-OV3 cells resulted in a significant decrease in hyperphosphorylated RB and RB-2/p130 and corresponding significant increases in the levels of hypophosphorylated and/or partially phosphorylated RB-2/p130 protein and hypophosphorylated RB. Also, RA treatment increased expression of the cdk inhibitor p27 and decreased activity of cdk 2, cdk 4 and cdk 6. Finally, amounts of p27-cyclin E and RB-2/p130-E2F4 complexes were found to increase in CA-OV3 cells growth arrested by RA. These results suggest that the pocket protein pathways are critical targets for retinoid suppression of ovarian carcinoma cell growth.

Blotting, Western↗
PubMed2001

New insight in cdk9 function: from Tat to MyoD.

Cdk9 is a serine-threonine cdc2-related kinase and its activity is not cell cycle-regulated. Cdk9 function depends on its kinase activity and also on its regulatory units: the T-family cyclins and cyclin K. Recently, several studies confirmed the role of cdk9 in different cellular processes such as signal transduction, basal transcription, HIV-Tat- and MyoD-mediated transcription and differentiation. All the referred data strongly support the concept of a multifunctional protein kinase with specific cytoplasmic and nuclear functions.

Animals↗
PubMed2001

Involvement of Wnt signaling pathway in murine medulloblastoma induced by human neurotropic JC virus.

By using the early genome of the human neurotropic polyomavirus, JCV, we have created transgenic animals that develop cerebellar primitive neuroectodermal tumors which model human medulloblastoma. Expression of T-antigen was found in some, but not all, tumor cells, and examination of the clonal cell lines derived from the tumor population showed enhanced tumorigenicity of cells expressing T-antigen in comparison to T-antigen negative cells. Considering the earlier notion on the potential involvement of beta-catenin with human medulloblastoma, we investigated various components of the Wnt signaling pathway including beta-catenin, its partner transcription factor, LEF-1, and their downstream target gene c-myc in these two cell populations. Immunohistochemical staining of the cells revealed enhanced nuclear appearance of beta-catenin in T-antigen positive cells. Results from Western blot showed higher levels of beta-catenin and LEF-1 in T-antigen positive cells in comparison to those in T-antigen negative cells. The enhanced level of LEF-1 expression correlated with the increase in DNA binding activity of this protein in nuclear extracts of T-antigen positive cells. Results from Northern and Western blot analyses revealed that the level of c-myc expression is augmented both at the RNA and protein levels in T-antigen positive cells. These observations corroborated results from transfection studies indicating the ability of JCV T-antigen to stimulate c-myc promoter activity. Further, co-transfection experiments revealed that the amount of c-myc and T-antigen protein in tumor cells may dictate the activity of JCV early promoter in these cells. These observations are interesting in light of recent discoveries on the association of JCV with human medulloblastoma and suggest that communication between JCV and the Wnt pathway may be an important event in the genesis of these tumors.

Animals↗
PubMed2001

Who is the boss in the retinoblastoma family? The point of view of Rb2/p130, the little brother.

This review portrays an updated overview about the possible tumor suppressive properties of the Rb2/p130 gene, the third member of the retinoblastoma (RB) family of genes, including RB itself and p107. After a brief analysis of the established structural and functional similarities among the three genes, the main purpose is to critically analyze present evidence whether Rb2/p130 shares the role of a tumor suppressor. Taking into account the well-proven growth suppressive properties of Rb2/p130 and p107, we discuss the analysis of mutated or deleted forms of Rb2/p130 found in a number of human cancers. Finally, we take into consideration the data provided by the targeted disruption of each RB family gene, alone or in combination, in the mouse model.

Animals↗
PubMed2001

RACK1 interacts with E1A and rescues E1A-induced yeast growth inhibition and mammalian cell apoptosis.

The adenoviral E1A proteins are able to promote proliferation and transformation, inhibit differentiation, induce apoptosis, and suppress tumor growth. The extreme N terminus and conserved region one of E1A, which are indispensable for transcriptional regulation and for binding to p300/CBP, TBP, and pCAF, play essential roles in these abilities. These observations strongly suggest an intrinsic link between E1A-mediated transcriptional regulation and other effects. In this report, we show that E1A inhibits the normal growth of Saccharomyces cerevisiae HF7c, and this inhibition also depends on the domains required for transcriptional regulation. We demonstrate that E1A associates with histone acetyltransferase activity and represses the transactivation activity of transcription factor in S. cerevisiae, suggesting that E1A may suppress the expression of genes required for normal growth. Based on yeast growth rescue, we present a genetic screening strategy that identified RACK1 as an E1A antagonizing factor. Expression of human RACK1 efficiently relieves E1A-mediated growth inhibition in HF7c and protects human tumor cells from E1A-induced apoptosis. Finally, we show that RACK1 decreases E1A-associated histone acetyltransferase activity in yeast and mammalian cells, and physically interacts with E1A. Our data demonstrate that RACK1 is a repressor of E1A, possibly by antagonizing the effects of E1A on host gene transcription.

Adenovirus E1A Proteins↗
PubMed2001

The retinoblastoma-related Rb2/p130 gene is an effector downstream of AP-2 during neural differentiation.

Rb2/p130, a member of the Retinoblastoma family of growth and tumour suppressor genes, is extensively implicated in the control of cell cycle and differentiation. The minimal promoter region of Rb2/p130 in T98G human glioblastoma cells was identified and its analysis revealed the presence of a KER1 palindromic sequence able to bind the transcription factor AP-2, a regulatory protein that plays a crucial role in ectodermal differentiation. This KER1 site interacted in vitro with AP-2, and AP-2 overexpression increased Rb2/p130 transcription and translation. We also found that rat PC12 pheochromocytoma cells, when induced to differentiate by NGF, displayed an increase of AP-2 protein levels and of Rb2/p130 transcription and protein levels. AP-2-transfected PC12 cells displayed enhanced transcription and translation of Rb2/p130 and of the cdk inhibitor p21(WAF1/CIP1), a gene known to be under the control of AP-2, but unable by itself to elicit PC12 differentiation. Overexpression of either AP-2 or Rb2/p130 elicited per se cell differentiation in the absence of NGF, while coexpression of AP-2B, a negative regulator of AP-2 transcriptional activity, inhibited only AP-2-induced differentiation. Altogether, these results indicate that Rb2/p130 is a critical effector of AP-2 in sustaining ectodermal differentiation.

Animals↗
PubMed2001

Cdk10, a Cdc2-related kinase, associates with the Ets2 transcription factor and modulates its transactivation activity.

Cdk10 is a Cdc2-related kinase that may play a role in regulating the G2/M phase of the cell cycle. However little is known about the proteins that interact with this putative kinase and contribute to its function in the cell. We report in this study that Cdk10 interacts with the N-terminus of the Ets2 transcription factor, which contains the highly conserved Pointed domain and transactivation domain. The Pointed domain has been implicated in protein-protein interactions and we find that Ets2 requires an intact Pointed domain to bind Cdk10. The Pointed domain of Ets1 is highly similar to Ets2, however Cdk10 does not recognize Ets1 in a two-hybrid assay thereby demonstrating significant binding specificity on the part of Cdk10. We find that Cdk10 binds full length Ets2 in vitro and in vivo and inhibits Ets2 transactivation in mammalian cells.

Binding Sites↗
PubMed2001

Application of the primer in situ DNA synthesis (PRINS) technique to titer recombinant virus and evaluation of the efficiency of viral transduction.

Titration is an important and critical step in dosing recombinant virus for gene therapy. We present a relatively fast, convenient, and sensitive method that allows for precise quantification of recombinant retrovirus. The method is based on PCR amplification of a foreign gene by the PRINS (primer in situ DNA synthesis) technique. The PRINS technique is based on the sequence-specific annealing of unlabeled oligonucleotide DNA in situ. This oligonucleotide operates as a primer for in situ chain elongation catalyzed by the Taq I polymerase. Using digoxygenin-labeled nucleotides as a substrate for chain elongation, the neo-synthetic DNA is labeled by an FITC-conjugated anti-digoxygenin antibody. To avoid the possibility of false positives, we amplified the puromycin-resistance gene, which is associated with the transgene in the same viral vector and is not normally present in mammalian cells. The retroviral titer was evaluated by counting fluorescein isothiocyanate-positive cells after PRINS labeling, while knowing the number of plated cells that were transduced with different amounts of viral supernatant. A comparable viral concentration of 1 x 10(7) infectious units/mL was found among the retroviruses.

Adenocarcinoma↗
PubMed2001

Mechanisms and immediate outcome of in-hospital cardiac arrest in patients with advanced heart failure secondary to ischemic or idiopathic dilated cardiomyopathy.

To differentiate patients with congestive heart failure who are more prone to develop malignant ventricular tachyarrhythmias or severe bradyarrhythmias as the terminal event, we retrospectively evaluated a group of 48 patients with advanced heart failure who experienced a monitored cardiac arrest during hospital stay. We found no significant differences with respect to several variables, apart from clinical status, which was worse in patients whose cardiac arrest was precipitated by severe bradycardia or electromechanical dissociation.

Adult↗
PubMed2001

RB2/p130 gene-enhanced expression down-regulates vascular endothelial growth factor expression and inhibits angiogenesis in vivo.

Angiogenesis is an essential step in the progression of tumor formation and development. The switch to an angiogenetic phenotype can occur as a distinct step before progression to a neoplastic phenotype and is linked to genetic changes such as mutations in key cell cycle regulatory genes. The pathogenesis of the angiogenetic phenotype may involve the inactivation of tumor suppressor genes such as the "guardian of the genome," p53, and the cyclin-dependent kinase inhibitor p16. Retinoblastoma family member RB2/p130 encodes a cell cycle regulatory protein and has been found mutated in different tumor types. Overexpression of RB2/p130 not only suppresses tumor formation in nude mice but also causes regression of established tumor grafts, suggesting that RB2/p130 may modulate the angiogenetic balance. We found that induction of RB2/p130 expression using a tetracycline-regulated gene expression system as well as retroviral and adenoviral-mediated gene delivery inhibited angiogenesis in vivo. This correlated with pRb2/p130-mediated down-regulation of vascular endothelial growth factor protein expression both in vitro and in vivo.

Animals↗
PubMed2001

Distinct regions of cyclinT1 are required for binding to CDK9 and for recruitment to the HIV-1 Tat/TAR complex.

Tat-mediated activation of the HIV-1 promoter activity requires Tat-dependent recruitment of the cyclinT1/CDK9 complex (P-TEFb) to the transacting element (TAR) RNA. Tat interaction with the cyclinT1, the regulatory partner of CDK9, results in a specific recruitment of the heterodimer CycT1/CDK9 complex to TAR, whereby it promotes transcription elongation of the HIV-1 LTR-mediated transcription. Using the yeast two-hybrid protein interaction assay we analyzed the binding between cyclinT1 and CDK9. Moreover, using a modified three-hybrid yeast interaction system, we analyzed the recruitment of CycT1 to the Tat/TAR complex. The data presented here demonstrated that distinct domains of cyclinT1 interact with CDK9 and Tat/TAR in vivo. These findings will be instrumental for the designing of proper dominant-negative P-TEFb components capable to interfere with Tat function. J. Cell. Biochem. Suppl. 36: 247-253, 2001.

Binding Sites↗
PubMed2001

pRb2/p130 and p107 control cell growth by multiple strategies and in association with different compartments within the nucleus.

It has been recently reported that retinoblastoma family proteins suppress cell growth by regulating not only E2F-dependent mRNA transcription but also rRNA and tRNA transcription and, through HDAC1 recruitment, chromatin packaging. In the present study we report data showing that these various control strategies are correlated, at least in part, with nuclear compartmentalization of retinoblastoma proteins. In a first series of experiments, we showed that pRb2/p130 and p107 are not evenly distributed within the nucleus and that cell cycle-dependent binding with E2F4 changes also as a function of their subnuclear localization. Namely, in the nucleoplasm pRb2/p130-E2F4 complexes are more numerous during G0/G1 while in the nucleolus they increase in S phase. Partially different functions for p107 are suggested since p107-E2F4 complexes in the nucleoplasm are more numerous is S phase with respect to G0/G1 and no cell cycle change is observed in the nucleolus. In a second series of experiments we showed that pRb2/p130, p107, E2F4, and pRb2/p130-HDAC1 complexes are all inner nuclear matrix-associated proteins and localize to sites different from pRb/p105 ones. We provide further evidence of multiple and partially distinct retinoblastoma protein family functional roles during cell cycle. Moreover, our data support emerging evidence for functional interrelationships between nuclear structure and gene expression.

Cell Compartmentation↗