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A De Luca

Publications and source records attributed to A De Luca.

At least 37 records · Page 2Linked to original sources
PubMed2004

Pattern of expression of cyclin D1/CDK4 complex in human placenta during gestation.

Progression through the cell cycle in eukaryotic cells is controlled by a family of protein kinases, termed cyclin-dependent kinases (CDKs), and their specific partners, the cyclins. In particular, the control of mammalian cell proliferation occurs largely during the G1 phase of the cell cycle. Five mammalian G1 cyclins have been enumerated to date: cyclins D1, D2, and D3 (D-type cyclins), and cyclins E and E2. By the use of immunohistochemistry and immunoelectron microscopy, we observed that in the first trimester of gestation of human placenta, cyclin D1 was distributed in the nuclei of the cytotrophoblast compartment together with a weak positivity of endothelial cells surrounding blood vessels. The endothelial positivity of cyclin D1 strongly increased in the third trimester of gestation. Moreover, we observed the subcellular localization of cyclin D1 that was present both in the stroma of placental villi and in the nuclei of syncytiotrophoblast cells. Therefore, we observed that CDK4 was localized in the nuclei of the cytotrophoblast compartment during the first and third trimesters and it also had a nuclear positivity in the endothelial cells of blood vessels at the end of the third trimester of gestation. In conclusion we may hypothesize that cyclin D1/CDK4 complex functions to regulate the cell cycle progression in the proliferative compartment of human placenta, the cytotrophoblast, during the first trimester through interaction with p107 and p130. Therefore, cyclin D1 and CDK4 seem to be involved in the control of placental angiogenesis during the third trimester of gestation.

Cell Cycle↗
PubMed2004

Evaluation of a DHPLC-based assay for rapid detection of RET germline mutations in Italian patients with medullary thyroid carcinoma.

Causative gain-of-function mutations of the RET tyrosine-kinase receptor gene have been reported in more than 95% of inherited cases of medullary thyroid carcinoma (MTC; OMIM# 155240). Most RET activating mutations are clustered in mutational "hot spots" in exons 10, 11, 13, 14, 15 and 16 and are usually detected by single-strand conformation polymorphism (SSCP) followed by direct sequencing. To improve sensitivity, time and costs of mutational screening we have developed a denaturing high performance chromatography (DHPLC) protocol, based on the detection of heteroduplex molecules by ion-pair reverse-phase liquid chromatography under partially denaturing conditions. The mutational screening of RET exons 10, 11, 13-16 was performed in a total of 111 subjects, including 45 MTC patients and 49 relatives with known RET mutations and 17 individuals, being at risk of hereditary MTC and carrying unknown RET alleles. Heteroduplex peaks with a distinct and reproducible DHPLC elution profile allowed the detection of both rare and common RET mutations. Overall, the DHPLC-based methodology showed a high level of sensitivity and accuracy, nearing 100%. Furthermore, our protocol showed the ability to identify: 1) all the mutated codons of RET located in the "hot spots" domain; 2) the different point mutations occurring in the same codon of RET gene; 3) less frequent or rare mutations; 4) polymorphisms. As such, it can be proposed as a relatively simple and highly accurate method for a rapid genetic testing for members of MTC families.

Carcinoma, Medullary↗
PubMed2004

Lopinavir plasma levels in salvage regimes by a population of highly active antiretroviral therapy-treated HIV-1-positive patients.

Increased lopinavir (LPV) exposure obtained in vivo through combination with low-dose ritonavir may overcome a certain grade of resistance but not all. We sought to analyze LPV variability and possible risk factors. LPV trough plasma concentrations were determined by high-performance liquid chromatography after 1, 4, and 12 weeks from salvage regimens and tested in both univariate and multivariate regression analyses with age, gender, weight, risk factors for HIV acquisition, hepatitis C virus reactivity, hepatitis B surface antigen positivity, baseline aspartate transferase (AST) or alanine transferase (ALT) levels, creatinine, non-nucleoside reverse transcriptase inhibitors (NNRTIs) or tenofovir as concomitant drugs, and NNRTIs administered in the previous regimen. Fifty-six patients were included into the study. Among them, 8 of 56 (14.3%) at week 1, 12 of 56 (21.4%) at week 4, and 9 of 56 (16.1%) at week 12 had suboptimal LPV plasma concentrations, defined as trough concentration less than 4 microg/mL. No correlation was found between LPV trough concentrations and assessed variables. In conclusion, pharmacokinetic variability and low LPV concentrations have been found, supporting the use of therapeutic drug monitoring in those starting this drug.

Adult↗
PubMed2004

Prognostic value of immunohistochemical expression of p53, bax, Bcl-2 and Bcl-xL in resected non-small-cell lung cancers.

AIMS: Some experimental evidence suggests that in lung cancer, development, progression and an increased proliferation rate can be linked to apoptosis-related factors. In this study we evaluated the possible role of p53 and Bcl-2 gene family members as prognostic factors for non-small-cell lung cancer. METHODS AND RESULTS: We investigated the immunohistochemical expression of p53 and Bcl-2 gene family members (bax, Bcl-2 and Bcl-xL) in 94 non-small-cell lung cancer specimens to establish the role of these genes in lung cancer pathogenesis, and to evaluate their prognostic importance. The expression of Bcl-2 was correlated with a shorter patient survival time and with the nodal status of the neoplasm. We also found frequent over-expression of bax and Bcl-xL to be of no prognostic significance. Finally, we found no correlation between frequent detection of aberrant p53 protein and expression of either Bcl-2, bax or Bcl-xL or with patient survival time. CONCLUSIONS: This study confirms a relevant role for apoptosis-regulatory proteins in the pathogenesis of lung cancer, and highlights the possible role of Bcl-2 as a prognostic factor for this tumour.

Apoptosis↗
PubMed2004

Small molecule epidermal growth factor receptor tyrosine kinase inhibitors: an overview.

The epidermal growth factor receptor (EGFR) has been identified as a relevant target for treatment of solid tumors, as it is involved in regulating cellular functions important in the proliferation and survival of cancer cells, is commonly expressed in a range of tumors, and high expression is often related to poor prognosis. Some of the most advanced target based agents in clinical development are the EGFR tyrosine kinase inhibitors (EGFR-TKIs). This brief review summarizes the results of phase II monotherapy trials of EGFR TKIs in cancer patients. The molecular mechanisms involved in regulating the sensitivity/resistance of tumor cells to EGFR-TKIs are also discussed.

Biological Availability↗
PubMed2004

Updated European recommendations for the clinical use of HIV drug resistance testing.

In most European countries, HIV drug resistance testing has become a routine clinical tool. However, its practical implementation in a clinical context is demanding. The European HIV Drug Resistance Panel was established to make recommendations to clinicians and virologists on this topic and to propose quality control measures. The panel recommends resistance testing for the following indications: i) drug-naive patients with acute or recent infection; ii) therapy failure, including suboptimal treatment response, when treatment change is considered; iii) pregnant HIV-1-infected women and paediatric patients with detectable viral load when treatment initiation or change is considered; and iv) genotype source patient when post-exposure prophylaxis is considered. In addition, for drug-naive patients with chronic infection in whom treatment is to be started, the panel suggests that resistance testing should be strongly considered and recommends testing the earliest sample for drug resistance if suspicion of resistance is high or prevalence of resistance in this population exceeds 10%. The panel does not favour genotyping over phenotype, however it is anticipated that genotyping will be used more often because of its greater accessibility, lower cost and faster turnaround time. For the interpretation of resistance data, clinically validated systems should be used to the greatest extent possible. It is mandatory that laboratories performing HIV resistance tests take regular part in quality assurance programs. Similarly, it is necessary that HIV clinicians and virologists take part in continuous education and meet regularly to discuss problematic clinical cases. Indeed, resistance test results should be used in the context of all other clinically relevant information for predicting therapy response. The panel also encourages the timely collection of epidemiological information to estimate the impact of transmission of resistant HIV and the prevalence of HIV-1 non-B subtypes in the different European countries.

Anti-HIV Agents↗
PubMed2003

The magnetic field of an isolated neutron star from X-ray cyclotron absorption lines.

Isolated neutron stars are highly magnetized, fast-rotating objects that form as an end point of stellar evolution. They are directly observable in X-ray emission, because of their high surface temperatures. Features in their X-ray spectra could in principle reveal the presence of atmospheres, or be used to estimate the strength of their magnetic fields through the cyclotron process, as is done for X-ray binaries. Almost all isolated neutron star spectra observed so far appear as featureless thermal continua. The only exception is 1E1207.4-5209 (refs 7-9), where two deep absorption features have been detected, but with insufficient definition to permit unambiguous interpretation. Here we report a long X-ray observation of the same object in which the star's spectrum shows three distinct features, regularly spaced at 0.7, 1.4 and 2.1 keV, plus a fourth feature of lower significance, at 2.8 keV. These features vary in phase with the star's rotation. The logical interpretation is that they are features from resonant cyclotron absorption, which allows us to calculate a magnetic field strength of 8 x 10(10) G, assuming the absorption arises from electrons.

Journal Article↗
PubMed2003

Shift from noradrenaline to adrenaline production in the adrenal gland of the lizard, Podarcis sicula, after stimulation with vasoactive intestinal peptide (VIP).

The aim of this study was to investigate the distribution and function of VIP in the adrenal gland of the lizard, Podarcis sicula. We have shown by immunohistochemistry that VIP fibers were localized exclusively around clusters of chromaffin cells in the dorsal ribbon of the lizard adrenal gland. Moreover, a strong positivity for this peptide was observed within ganglial cells and within most chromaffin cells of the gland. To investigate the effects of VIP on the adrenal gland, we have treated lizards with several doses of this peptide and we have shown that injections of exogenous VIP increased plasma levels of catecholamines and corticosteroids, but not of ACTH. This probably suggests a direct effect of VIP on the control of adrenal hormone secretion without the involvement of the hypothalamo-hypophyseal axis. Our results also establish that the increased levels of the hormones were modulated in a time- and dose-dependent manner. Therefore, our morphological studies showed a clear increased function of steroidogenic cells. In the medullary region, VIP administration induced not only a functional enhancement of adrenaline release from adrenergic cells, but also a shift of noradrenaline cells to adrenaline ones.

Adrenal Cortex Hormones↗
PubMed2003

Lymphocytes apoptosis: young versus aged and humans versus rats.

This paper deals with a comparative study of lymphocyte apoptosis in young versus aged and humans versus rats. Apoptotic rate achieved by the use of different apoptogenic inducers, acting at different cellular levels, and cell surface modifications were analyzed. The results showed that aged human lymphocytes and freshly isolated rat lymphocytes were more prone to undergo apoptosis. Therefore, the same apoptotic signal is recognized by human and rat lymphocytes, but the extent of the answer is related to the species, to the intensity of the apoptotic stimulus and to the metabolic/developmental condition of the cells. Surface modifications (lipids and glycans), typical of apoptosis, were observed. Our data showed that cell surface changes are species and age dependent. They are early events, progressively achieved in the course of the apoptotic process involving lateral membrane movements of molecules.

Adult↗
PubMed2003

Target-based agents against ErbB receptors and their ligands: a novel approach to cancer treatment.

The ErbB receptors and their cognate ligands that belong to the epidermal growth factor (EGF) family of peptides are involved in the pathogenesis of different types of carcinomas. In fact, the ErbB receptors and the EGF-like growth factors are frequently expressed in human tumors. These proteins form a complex system that regulates the proliferation and the survival of cancer cells. Therefore, ErbB receptors and their ligands might represent suitable targets for novel therapeutic approaches in human carcinomas. In this regard, different target-based agents that are directed against the ErbB receptors have been developed in the past two decades. One of these compounds, the humanized anti-ErbB-2 monoclonal antibody trastuzumab has been approved for the treatment of patients with metastatic breast cancer. The anti-EGF receptor (EGFR) antibody C225, as well as EGFR tyrosine kinase inhibitors ZD1839 and OSI-774 are currently in phase III clinical development. Several other ErbB tyrosine kinase inhibitors are in phase I/II studies. These compounds have generally been shown to have an acceptable toxicity profile and promising anti-tumor activity in heavily pretreated patients. The mechanisms of action of these compounds, as well as the potential therapeutic strategies to improve their efficacy are discussed in this review with particular regard to the combinations of anti-ErbB agents with cytotoxic drugs, or combinations of different ErbB-targeting agents.

Animals↗
PubMed2003

Hepatic clearance of apoptotic lymphocytes: simply removal of waste cells?

The in situ liver recognition of apoptotic lymphocytes was studied by using different sources of lymphocytes (i.e. human, rat and mouse) and animal models (i.e. rat and mouse). Lymphocytes were induced to apoptosis using 10(-2)M cycloheximide for up to 24 hours; three types of apoptosing lymphocytes, corresponding to different stages in the apoptotic process, were described: type 1 or early apoptosis, type 2 or mature apoptosis and type 3 or late/necrotic apoptosis. When livers were in situ injected with apoptotic lymphocytes enriched for type 1 (early), 2 (mature) or 3 (late/necrotic) apoptosis, they recognized and internalized apoptosing cells, with an efficiency directly dependent on the stage of the apoptotic process. The highest recognition rate, which was, in all cases, mediated by galactose- and mannose-specific receptors, was obtained with homologous apoptotic cells (i.e. rat lymphocytes and rat liver). Moreover, the drastically reduced efficiency of recognition of human or mouse apoptotic lymphocytes when injected into rat liver, suggested the involvement also of species-specific antigens.

Adult↗
PubMed2001

Gating of myotonic Na channel mutants defines the response to mexiletine and a potent derivative.

BACKGROUND: Myotonia and periodic paralysis caused by sodium channel mutations show variable responses to the anti-myotonic drug mexiletine. OBJECTIVE: To investigate whether variability among sodium channel mutants results from differences in drug binding affinity or in channel gating. METHODS: Whole-cell sodium currents (I(Na)) were recorded in tsA201 cells expressing human wild-type (WT) and mutant skeletal muscle sodium channels (A1156T, hyperkalemic periodic paralysis; R1448C, paramyotonia congenita; G1306E, potassium-aggravated myotonia). RESULTS: At a holding potential (hp) of -120 mV, mexiletine produced a tonic (TB, 0.33 Hz) and a use-dependent (UDB, 10 Hz) block of peak I(Na) with a potency following the order rank R1448C > WT approximately equal A1156T > G1306E. Yet, when assayed from an hp of -180 mV, TB and UDB by mexiletine were similar for the four channels. The different midpoints of channel availability curves found for the four channels track the half-maximum inhibitory value (IC50) measured at -120 mV. Thus differences in the partitioning of channels between the closed and fast-inactivated states underlie the different IC50 measured at a given potential. The mexiletine-derivative, Me7 (alpha-[(2-methylphenoxy)methyl]-benzenemethanamine), behaved similarly but was approximately 5 times more potent than mexiletine. Interestingly, the higher drug concentrations ameliorated the abnormally slower decay rate of myotonic I(Na). CONCLUSIONS: These results explain the basis of the apparent difference in block of mutant sodium channels by mexiletine and Me7, opening the way to a more rationale drug use and to design more potent drugs able to correct specifically the biophysical defect of the mutation in individual myotonic patients.

Cell Line, Transformed↗
PubMed2001

Low frequency of severe hepatotoxicity and association with HCV coinfection in HIV-positive patients treated with HAART.

BACKGROUND: Highly active antiretroviral therapy (HAART) is strongly effective in reducing morbidity and mortality in HIV-1-positive individuals. Its main drawback is the potential toxicity. Data on the frequency and determinants of severe hepatotoxicity in a clinical setting are still sparse. METHODS: This is a prospective study of HIV-1-positive individuals with known HBsAg and HCV-Ab serology. The study end point was progression to alanine aminotransferase (ALT) levels > or =200 IU/L after HAART initiation. Cumulative probability of progression to this end point was estimated by the Kaplan-Meier method. Crude and adjusted hazard ratios (HR) were estimated by proportional hazards regression model. RESULTS: One thousand two hundred fifty-five patients were included. HBsAg was found in 91 (7.2%), HCV-Ab in 578 (46.5%) patients; almost all injection drug users (451 of 482; 93.6%) were HCV-Ab positive. Sixty-one individuals progressed to the end point with a probability of 7.9% (95% confidence interval [CI], 5.6-10.0) of progression at 24 months from starting. Independent factors predicting progression to the end point were baseline ALT levels (HR, 5.29; 95% CI, 3.24-8.65; every 10 IU/L higher), HCV-Ab positivity (HR, 4.01; 95% CI, 1.48-10.85) or both HBsAg and HCV Ab positivity (HR, 3.85, 95% CI, 1.01-14.61), and previous non-HAART therapy (HR, 1.84, 95% CI, 1.04-3.42). Patients receiving stavudine-containing regimens had a lower risk than those receiving zidovudine-containing regimens (HR, 0.30, 95% CI, 0.12-0.71). CONCLUSIONS: There was a low risk of ALT > or =200 IU/L in our cohort. Hepatitis C coinfection and elevated ALT levels at HAART initiation are important predictors of progression to ALT > or =200 IU/L; stavudine-containing regimens were associated with a lower risk compared with zidovudine-containing regimens.

Alanine Transaminase↗
PubMed2001

Better response to chemotherapy and prolonged survival in AIDS-related lymphomas responding to highly active antiretroviral therapy.

OBJECTIVES: To evaluate the impact of response to highly active antiretroviral therapy (HAART) on the natural history of AIDS non-Hodgkin's lymphoma (NHL) and to analyse the feasibility, efficacy and toxicity of HAART in combination with chemotherapy. DESIGN: Prospective observational study in two AIDS clinical centres in Italy. METHODS: All consecutive HIV-infected patients with NHL were included (n = 44; 48% high-risk group) and prospectively followed for 27 months. HAART was administered concomitantly with chemotherapy. The association between response to HAART and clinical presentation, response to chemotherapy and toxicity was analysed by univariate and multivariate models. Survival analysis was performed by Kaplan-Meier estimates and the Cox proportional hazards regression model. RESULTS: A complete response (CR) to chemotherapy was achieved in 71% of HAART responders and 30% of non-responders. Virological response to HAART was the only variable associated with tumour response on multivariate analysis. A higher relative dose intensity (RDI) of chemotherapy was administered in patients with virological response compared with those without. The probability of 1 year survival was higher in patients with virological or immunological response. At Cox regression analysis, immunological response, a higher RDI and a CR to chemotherapy were all associated with a reduced risk of death. CONCLUSION: In HIV-infected patients with NHL, response to HAART was strongly associated with a better response to chemotherapy and prolonged survival. Concurrent treatments were well tolerated, and HAART-responder patients could receive a higher RDI of chemotherapy. In patients with AIDS lymphomas, combining HAART with chemotherapy could be a feasible and effective approach.

Adult↗
PubMed2001

Female sex and the use of anti-allergic agents increase the risk of developing cutaneous rash associated with nevirapine therapy.

To identify factors associated with cutaneous rash, we performed a retrospective multicentre analysis of HIV outpatients starting a highly active antiretroviral therapy regimen containing nevirapine. A total of 62 cutaneous adverse events were observed in 429 patients. Rash hazard was increased in women, by the prophylactic use of glucocorticoids or antihistaminics, and was reduced by escalating the initial dose of nevirapine. Women receiving glucocorticoids had a 3 month cumulative probability of rash of 0.41.

Adult↗
PubMed2001

Association study of a promoter polymorphism of UFD1L gene with schizophrenia.

Schizophrenia or schizoaffective disorders are often found in patients affected by DiGeorge/velo-cardio-facial syndrome (DGS/VCFS) as a result of hemizygosity of chromosome 22q11.2. We evaluated the UFD1L gene, mapping within the DGS/VCFS region, as a potential candidate for schizophrenia susceptibility. UFD1L encodes for the ubiquitin fusion degradation 1 protein, which is expressed in the medial telencephalon during mouse development. Using case control, simplex families (trios), and functional studies, we provided evidence for association between schizophrenia and a single nucleotide functional polymorphism, -277A/G, located within the noncoding region upstream the first exon of the UFD1L gene. The results are supportive of UFD1L involvement in the neurodevelopmental origin of schizophrenia and contribute in delineating etiological and pathogenetic mechanism of the schizophrenia subtype related to 22q11.2 deletion syndrome.

Adaptor Proteins, Vesicular Transport↗