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Biomedical subjects

G Palù

Publications and source records attributed to G Palù.

At least 37 records · Page 2Linked to original sources
PubMed2001

Evaluation of a near-patient test and 2 enzyme-linked immunosorbent assay-based assays for detecting anti-herpes simplex virus type-2 antibodies.

Several type-specific serologic assays for herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), based on glycoprotein G1 (gG1) and gG2, have recently been developed. These include immunodot (POCkit HSV-2) and enzyme-linked immunosorbent assay (ELISA). The diagnostic value of POCkit HSV-2, a near-patient test, and of 2 immunoenzymatic, type-specific assays was evaluated on 122 patients attending an STD clinic. Western blot was used as the reference test. The sensitivity of POCkit HSV-2 was good but the specificity was poor, so that in a population with low seroprevalence, a positive result is likely to be a false positive. Analysis of 2 currently available HSV type-specific ELISAs yielded results suggesting that the sensitivity of these tests may also be suboptimal.

Antibodies, Viral↗
PubMed2001

Viral load in HCV RNA-positive pregnant women.

OBJECTIVES: The risk of hepatitis C virus (HCV) infection in the newborn is estimated to be around 5%, but becomes very high in the case of coinfection with HIV. One of the main factors associated with the vertical transmission of HCV is the viral load. Our objective was to investigate the behavior of HCV viral load during pregnancy in relation to HIV coinfection, liver enzymes, and vertical transmission. METHODS: Three thousand seven hundred forty-eight women seen consecutively in their first trimester of pregnancy were screened for HCV infection. Sixty-five were found to be anti-HCV+/HCV RNA+ and were followed up with clinical and serological assessment (i.e., transaminases and quantitative polymerase chain reaction [PCR] for viral load) in their second and third trimesters and 6 months after delivery. All were anti-HIV and hepatitis B surface antigen negative. HCV RNA was 12.0+/-19.9 x 10(6) copies/ml in the first trimester and 10.9+/-13.3 x 10(6) in the second, but increased to 19.5+/-25.1 x 10(6) in the third trimester. Six months after delivery the viral load returned to the baseline levels; the changes in viral load did not reach any statistical significance, however. Transaminases tended toward a reduction from the baseline during the second and third trimesters, and then an increase in both AST and ALT was recorded 6 months after delivery. However, when the group whose AST/ALT were found abnormal at the first test was considered, no significant changes were recorded during the follow-up. The overall rate of vertical transmission was 4.6 CONCLUSIONS: With HCV+ mothers monitoring transaminases during pregnancy is unnecessary, and testing liver enzymes at the beginning of pregnancy is sufficient. Qualitative PCR should be done once during the pregnancy, but any staging of the liver disease should be taken after delivery. Quantitative PCR testing is expensive and pointless. Any decision for elective cesarean section in HCV RNA+ mothers should be confirmed by other studies.

Alanine Transaminase↗
PubMed2001

Molecular analysis of CDKN1C and TP53 in sporadic adrenal tumors.

OBJECTIVE: To evaluate the roles of the CDKN1C (P57KIP2) gene, which encodes for the cyclin-dependent kinase inhibitor CDNC, and the TP53 tumor suppressor gene in adrenal tumorigenesis, as a means of investigating the molecular basis of sporadic adrenal tumors, which is unknown. DESIGN: Screening for the presence CDKN1C and TP53 mutations and analyzing the expression pattern of CDNC, P53 and its downstream effector CDN1 (P21WAF1/CIP1) in a series of 79 sporadic adrenal tumors. METHODS: Single-strand conformation polymorphism and sequencing were used for mutation analysis of CDKN1C and TP53 in blood and adrenal tissue samples. In a subgroup of 48 tissues, CDKN1C expression was evaluated by RT-PCR and immunohistochemistry. Immunohistochemical analysis of P53 and CDN1 was performed. RESULTS: No somatic mutations of CDKN1C were found in the tumors analyzed, in spite of low/absent CDNC expression in adrenocortical adenomas and carcinomas. Mutations in the TP53 gene were present in 70% of adrenocortical carcinomas, associated with abnormal P53 and CDN1 expression, but not in benign neoplasms. In the normal adrenal cortex, CDNC expression was strictly nuclear and confined to the cortical zone (i.e. zona glomerulosa and reticularis), with no staining in the medulla. CONCLUSIONS: Mutations in the TP53 gene are frequent in adrenocortical carcinomas and might be used as a marker of malignancy. In the normal adrenal cortex, the zone-specific pattern of expression of CDNC suggests a role in adrenal differentiation.

Adrenal Gland Neoplasms↗
PubMed2001

Gene therapy of brain and endocrine tumors.

Gene therapy of cancer has become a major interest of medical research since more than 60% of the ongoing gene therapy protocols today involve cancer patients. To increase the therapeutic index of cancer gene therapy, targeting strategies have been developed to ensure that the expression of therapeutic genes is restricted exclusively to the tissue of interest. An attractive approach lies in the possibility to control the expression of therapeutic genes at the transcriptional level by the introduction of tissue-specific or tumor-specific enhancers/promoters offers. We have developed transcriptionally targeted vectors for gene therapy of solid tumors, including malignant gliomas and epithelial thyroid tumors. The choice of these tumor types relies on their clinical impact, ie, morbidity and mortality, the lack of effective conventional therapeutic strategies, and the ability of these tumors to express tissue/tumor-specific genes, whose transcriptional control elements (enhancer/promoter) may be used for achieving selective transgene expression. Here we report our clinical and preclinical experience in gene therapy of brain and thyroid tumors, and review the literature published on this topic.

Brain Neoplasms↗
PubMed2001

Abnormal propeptide processing resulting in the presence of two abnormal species of protein C in plasma: characterization of the dysfunctional protein C Padua3 (protein C(R-1L/propeptide)).

A heterozygous G-->T transversion at position 1388 of the protein C (PC) gene which predicted the substitution of Arg(-1) to a Leu (PC(R-1L)) was identified in a thrombophilic patient. The PC(R-1L) was purified from the patient's plasma by immunoaffinity chromatography using Ca++-independent and Ca++-dependent monoclonal antibodies. NH2-terminal sequencing of the light chain of PC(R-1L) revealed two amino acid sequences: one was identical to the complete propeptide sequence of PC, while the other matched the normal PC light chain sequence elongated by one amino acid (Leucine at position 1). Activated PC(R-1L/propeptide) exhibited normal amidolytic and impaired anticoagulant activity. Thus, the substitution of a Leu for an Arg at position -1 of PC shifts the propeptidase cleavage site by one amino acid. In addition, in PC(R-1L/propeptide) the propeptide cleavage at Lys(-2) is less efficient since approximately 60% of PC variant molecules present in patient's plasma retained the entire propeptide. Our findings suggest that depending on the specific amino acid substitution at position-1, PC can be secreted in plasma containing the entire propeptide attached to the light chain. Impaired interaction of elongated APC molecules with a membrane-surface and/or factor Va which is the physiological substrate for APC, is manifested in vivo by thrombophilia.

Amino Acid Sequence↗
PubMed2001

Molecular basis of the interactions between herpes simplex viruses and HIV-1.

Herpes simplex virus types 1 and 2 (HSV-1 and -2) are two of the major opportunistic agents involved in the pathogenesis of AIDS, which is caused by human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2). A body of evidence suggests that they can also act as co-factors by interacting with HIV-1, thereby influencing disease progression. Indeed, the HIV-1 life cycle can be affected by HSV at different levels of interaction, both in vitro and in vivo: (i) transactivation of the HIV-1 long terminal repeat can be mediated, probably through different pathways, by HSV-1-infected cell protein (ICP)0, ICP4, ICP27 and US11 gene products; the HSV-1 transactivator viral protein 16 is not able to transactivate the long terminal repeat; (ii) cytokine release and antigen presentation from HSV-infected cells are both able to stimulate HIV-1 expression; (iii) Pseudotyping of the HIV-1 core particle with HSV-1 envelope glycoproteins can expand HIV-1 tropism to new cell types. Moreover, in vivo studies report that aciclovir treatment can produce a survival benefit in HIV-1-infected patients and that recurrent genital herpes appears to be linked to HIV-1 transmission by both boosting plasma retroviral load and providing a portal of entry and exit for HIV-1.

AIDS-Related Opportunistic Infections↗
PubMed2000

The catalytic subunit of herpes simplex virus type 1 DNA polymerase contains a nuclear localization signal in the UL42-binding region.

The herpes simplex virus type 1 DNA polymerase consists of a catalytic subunit (POL or UL30) and a processivity factor (UL42). The POL/UL42 interaction, which occurs through the extreme C-terminus of POL, is essential for HSV-1 replication and thus represents a valid target for drug inhibition. We recently showed (A. Loregian et al. (1999) Proc. Natl. Acad. Sci. USA 96, 5221-5226) that an oligopeptide corresponding to the 27 C-terminal amino acids of POL, when delivered into herpes simplex virus type 1-infected cells by a protein carrier, was able to localize into the nucleus and to inhibit viral replication by disruption of the POL/UL42 interaction. In this report, to further characterize the 27 mer (Pol peptide), we investigated whether its nuclear localization was due to the presence of a nuclear localization signal. By testing the ability of the Pol peptide to localize the beta-galactosidase, a normally cytoplasmic protein, to the nucleus, we confirmed that the Pol peptide contained a functional nuclear localization signal, corresponding to the RRMLHR motif. This sequence proved not only necessary but also sufficient for nuclear localization, because its substitution with a six-alanine stretch prevented nuclear translocation of the beta-galactosidase-Pol peptide fusion. Site-directed mutagenesis experiments on this revealed that both the three basic arginines and the two hydrophobic residues Met and Leu were crucial for nuclear targeting. Finally, functionally equivalent sequences were also found in the C-terminus of the catalytic subunits of human cytomegalovirus (RRLHL) and of equine herpesvirus-1 DNA polymerase (RRILH).

Amino Acid Sequence↗
PubMed2000

Aloe-emodin is a new type of anticancer agent with selective activity against neuroectodermal tumors.

Here we report that aloe-emodin (AE), a hydroxyanthraquinone present in Aloe vera leaves, has a specific in vitro and in vivo antineuroectodermal tumor activity. The growth of human neuroectodermal tumors is inhibited in mice with severe combined immunodeficiency without any appreciable toxic effects on the animals. The compound does not inhibit the proliferation of normal fibroblasts nor that of hemopoietic progenitor cells. The cytotoxicity mechanism consists of the induction of apoptosis, whereas the selectivity against neuroectodermal tumor cells is founded on a specific energy-dependent pathway of drug incorporation. Taking into account its unique cytotoxicity profile and mode of action, AE might represent a conceptually new lead antitumor drug.

Animals↗
PubMed2000

Production of epidermal growth factor in human prostatic cells cultured in vitro.

The Epidermal Growth Factor (EGF) plays an important role in the regulation of in vitro growth of prostate cells inducing a strong mitogenic effect. Nevertheless in our previous study we observed that the treatment of human hypertrophic prostate cell line U285 with exogenous EGF produces a restricted effect on the cellular growth rate. This phenomenon could be due to the capacity of the cells to produce EGF. In this study we aimed to verify this hypothesis by evaluating the presence of mRNA of EGF and EGF receptor (EGF-R) and of their translation products in U285 cells, before and after the treatment with suramin and exogenous EGF. Moreover we studied the effects exerted by these substances on the proliferative rate of the cells U285 after different treatment protocols. The presence in the cells of mRNA for EGF and EGF-R and of their translation products was demonstrated by means of reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical methods respectively. The modification of growth rate induced by these drugs was studied by FRAME Cytotoxicity Test. The operative modalities adopted to carry out these growth assays tended to 1) focus the effects of suramin in relation to in vitro cellular growth phase; 2) verify the reversibility of its effects; 3) ascertain if it was possible to antagonize the action of suramin by adding exogenous EGF. The results obtained from the RT-PCR showed the presence, in the control cells and in the treated ones, of mRNA coding for EGF and EGF-R. The immunocytochemical analysis indicated that 20% of the control cells are EGF positive, and 83% are EGF-R positive, confirming the results obtained with RT-PCR. Moreover, these stainings showed that the treatment with EGF does not significantly modify the percentage of cells marked by the anti-EGF antibody, while treatments with suramin and suramin plus EGF double this percentage. None of the treatments modifies the percentage of EGF-R positive cells. The growth assays showed that the exposition to highest doses of suramin in the first 24 h of cultures causes a decrease (p < 0.05) of the cellular proliferation during the following 48 h and 72 h and that these effects are irreversible. Moreover, a contemporaneous exposition of the cells to EGF and suramin at seeding strengthens the cytotoxic action of the last drug. To sum up, the demonstration of the presence in the U285 cells of mRNA coding for EGF and EGF-R and of the corresponding proteins, confirms the hypothesis that these cells can produce EGF. Moreover, the cytotoxicity experiments allowed a focusing of the role of the endogenous EGF in the regulation of the U285 cells proliferation and confirmed the importance of biological events that take place in U285 cells during the first 24 h of culture.

Analysis of Variance↗
PubMed2000

Aspartic protease inhibitors. An integrated approach for the design andsynthesis of diaminodiol-based peptidomimetics.

Aspartic proteases play key roles in a variety of pathologies, including acquired immunodeficiency syndrome. Peptidomimetic inhibitors can act as drugs to combat these pathologies. We have developed an integrated methodology for preparing human immunodeficiency virus (HIV)-1 aspartic protease diaminodiol inhibitors, based on a computational method that predicts the potential inhibitory activity of the designed structures in terms of calculated enzyme-inhibitor complexation energies. This is combined with a versatile synthetic strategy that couples a high degree of stereochemical control in the central diaminodiol module with complete flexibility in the choice of side chains in the core and in flanking residues. A series of 23 tetrameric, pentameric and hexameric inhibitors, with a wide range of calculated relative complexation energies (-47.2 to +117 kJ.mol-1) and predicted hydrophobicities (logPo/w = 1.8-8.4) was thus assembled from readily available amino acids and carboxylic acids. The IC50 values for these compounds ranged from 3.2 nM to 90 microM, allowing study of correlations between structure and activity, and individuation of factors other than calculated complexation energies that determine the inhibition potency. Multivariable regression analysis revealed the importance of side-chain bulkiness and rigidity at the P2, P2' positions, suggesting possible improvements for the prediction process used to select candidate structures.

Computational Biology↗
PubMed2000

PCR in meningoencephalitis diagnosis.

Polymerase chain reaction (PCR) detection of a stretch of nucleic acid sequence of microbial origin from a clinical sample is not always diagnostic of disease unless the identified agent is a strict pathogen or its growth is documented. We describe here a case of acute meningoencephalitis in a 21-y-old man, in whom no pathogen was isolated by traditional bacterial or viral culture. Standard DNA PCR performed on the cerebrospinal fluid (CSF) identified the presence of 3 infectious agents: HHV-6, HHV-7 and Mycoplasma pneumoniae. Additional PCRs performed on CSF fractions along with gene transcript analysis proved the bystander role of the 2 herpesviruses and indicated M. pneumoniae as the relevant replicating agent, most likely playing to be a pathogenic role. Until this useful analysis becomes routine, clinicians should deal carefully with DNA PCR results, especially when assessing the aetiological role of agents, such as herpesviruses, which are known to undergo latency.

Acute Disease↗
PubMed2000

New perspectives for gene therapy in endocrinology.

Gene therapy for endocrine diseases represents an exciting new type of molecular intervention that may be a curative one. Endocrine disorders that might be treated by gene therapy include monogenic diseases, such as GH deficiency and hypothalamic diabetes insipidus, and multifactorial diseases, such as diabetes mellitus, obesity and cancer. Premises seem promising for endocrine tumours, but many combined approaches of cell and gene therapy are foreseeable also for other endocrine disorders. This review outlines the principles of gene therapy, describes the endocrine disorders that might take advantage of gene transfer approaches, as well as the gene therapy interventions that have already been attempted, their major limitations and the problems that remain to be solved.

Animals↗
PubMed2000

[Pregnancy in women infected with the hepatitis C virus].

The prevalence of HCV-RNA positivity in pregnant women goes from 1.2% to 4.5% in different countries. The aim of our study is to show pregnancy outcome, vertical/perinatal transmission rate, the viral load and the tramnsaminases trend during pregnancy and after delivery. The study involved 11,681 pregnant women screened in the Obstetric Department for High Risk Pregnancy at the University of Padua between 1992 and 1999. We evaluated the markers of HCV, HBV, HIV, the viral load and genotype and AST/ALT in the mothers and positivity and viral load of HCV-RNA in the newborns at birth and at 3rd, 6th, 9th, 12th month. Of the 11,681 pregnant women, 135 (1.15%) tested positive for the presence of anti-HCV antibodies and of the 135 anti-HCV antibody-positive mothers, 80 were found to be positive for HCV-RNA. Of 80 pregnancies that were HCV-RNA positive, 4 termined in abortion, 1 in stillborn, 1 in neonatal death, 18 in preterm delivery and 56 were carried to term. We came to the conclusion that HCV infection does not increase the risk of obstetric complications and does not influence the fetal-neonatal status at delivery; the pregnancy evolution may be complicated by the onset of cholestatsis in the 2nd and 3rd trimester; vertical transmission of the infection develops in few cases (4.8%), more likely at delivery.

Female↗
PubMed1999

Herpes simplex virus chronically infected human T lymphocytes are susceptible to HIV-1 superinfection and support HIV-1 pseudotyping.

Peripheral blood lymphocytes (PBL) and CEM CD4+ T-cell line can be infected by herpes simplex virus-1 (HSV-1). CEM cells were characterized as a cellular model to study interactions occurring between HSV-1 and HIV-1. Virtually all cells were persistently infected by HSV-1 (CEM(HSV)) and expressed the latency associated transcripts, whereas only a fraction tested positive for HSV-antigens. CD4 and CXCR-4 expression and function were not affected in CEM(HSV) cells and no significant increase of deoxyribonucleotide pools was noticed. Superinfection of CEM(HSV) cells with HIV-1 led to a cell line chronically infected by both viruses (CEM(HSV/HSV)). Evidence was also obtained that this cell line can produce HIV-1 pseudotyped by HSV-1 envelope. These results may have important implications for a better understanding of AIDS pathogenesis.

Animals↗
PubMed1999

Intranuclear delivery of an antiviral peptide mediated by the B subunit of Escherichia coli heat-labile enterotoxin.

We report an intracellular peptide delivery system capable of targeting specific cellular compartments. In the model system we constructed a chimeric protein consisting of the nontoxic B subunit of Escherichia coli heat-labile enterotoxin (EtxB) fused to a 27-mer peptide derived from the DNA polymerase of herpes simplex virus 1. Viral DNA synthesis takes places in the nucleus and requires the interaction with an accessory factor, UL42, encoded by the virus. The peptide, designated Pol, is able to dissociate this interaction. The chimeric protein, EtxB-Pol, retained the functional properties of both EtxB and peptide components and was shown to inhibit viral DNA polymerase activity in vitro via disruption of the polymerase-UL42 complex. When added to virally infected cells, EtxB-Pol had no effect on adenovirus replication but specifically interfered with herpes simplex virus 1 replication. Further studies showed that the antiviral peptide localized in the nucleus, whereas the EtxB component remained associated with vesicular compartments. The results indicate that the chimeric protein entered through endosomal acidic compartments and that the Pol peptide was cleaved from the chimeric protein before being translocated into the nucleus. The system we describe is suitable for delivery of peptides that specifically disrupt protein-protein interactions and may be developed to target specific cellular compartments.

3T3 Cells↗
PubMed1999

Crystal structure of the B subunit of Escherichia coli heat-labile enterotoxin carrying peptides with anti-herpes simplex virus type 1 activity.

Two chimeric proteins, consisting of the B subunit of Escherichia coli heat-labile enterotoxin with different peptides fused to the COOH-terminal ends, have been crystallized and their three-dimensional structure determined. The two extensions correspond to (a) a nonapeptide representing the COOH-terminal sequence of the small subunit of herpes simplex virus type 1 ribonucleotide reductase and (b) a 27-amino acid long peptide, corresponding to the COOH-terminal end of the catalytic subunit (POL) of DNA polymerase from the same virus. Both proteins crystallize in the P41212 space group with one pentameric molecule per asymmetric unit, corresponding to a solvent content of about 75%. The overall conformation of the B subunit pentamer in the two chimeric proteins, which consists of five identical polypeptide chains, is very similar to that in the native AB complex and conforms strictly to 5-fold symmetry. On the contrary, the peptide extensions are essentially disordered: in the case of the nonapeptide, only 5 and 6 amino acids were, respectively, positioned in two monomers, while in the other three only 2 residues are ordered. The extension is fully confined to the surface of the pentamer opposite to the face that interacts with the membrane and consequently it does not interfere with the ability of the B subunit to interact with membrane receptors. Moreover, the conformational flexibility of the two peptide extensions could be correlated to their propensity for proteolytic processing and consequent release of a biologically active molecule into cultured cells.

Animals↗
PubMed1999

In pursuit of new developments for gene therapy of human diseases.

Gene therapy aims at transferring a therapeutic gene into human somatic cells in order to treat a disease. Originally addressed to hereditary genetic disorders, gene therapy has found therapeutic applications in cancer, infectious diseases and degenerative disorders, particularly those of the nervous system. Although gene transfer into humans has been demonstrated in several clinical trials, with more than 300 currently underway worldwide, there is still no single outcome that undoubtedly showed a consistent benefit for the patient. Nevertheless, the expectations for gene therapy are still high, and the prospects of future clinical success are increasing together with the growing of the field. The development of better delivery systems specifically tailored to individual diseases, with sustained expression of the therapeutic gene in the appropriate cells, will in the end make possible true therapeutic applications of human gene transfer.

Acquired Immunodeficiency Syndrome↗