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Biomedical subjects

R Giuliani

Publications and source records attributed to R Giuliani.

At least 19 recordsLinked to original sources

A comparative in vitro study of the toxic potency of five inorganic lead compounds on a rat liver epithelial cell line (REL).

Relative insolubility of inorganic Pb compounds is one of the major problems in the evaluation of the toxicological profile of this metal. Different characteristics of Pb-containing solutions may, in fact, alter the biological properties of Pb compounds and influence their toxic potency. To investigate these aspects, we used selected experimental conditions to evaluate and compare the specific biological effects of five inorganic Pb compounds (soluble salts and oxide) on the viability and proliferation rate of a rat liver-derived cell line (REL cells). The study was performed according to classical toxicological criteria (dose- and time-response, reversibility/transience of the effect). Each Pb compound was accurately solubilised and the quantification of the real concentration of Pb(II) ions was performed either on the culture media used for each treatment, or on the extracts of exposed cells. Our study shows that four, out of the five Pb compounds we tested, induce the same dose- and time-related anti-proliferative effects on REL cells, being these effects also reversible, transient and directly related to the intracellular content of the metal. Since the intracellular concentration of the metal and, consequently, its biological effects on REL cells, directly depends on the bioavailability of the Pb(II) cation present in the treatment solutions, our results indicate that, in the experimental procedures aimed to assess the toxic potency of this metal, the solubility of each Pb compound should be carefully evaluated and taken into account.

Animals↗

Human herpesvirus-8-related Kaposi's sarcoma after liver transplantation successfully treated with cidofovir and liposomal daunorubicin.

The iatrogenic form of Kaposi's sarcoma (KS) is typically observed among transplant recipients, and the most appropriate therapeutic approach (usually including reduction of immunosuppression, specific chemotherapy, and/or administration of antiviral agents against human herpes virus-8) is still controversial. Available experiences on the effect of the anti-herpes viruses drug cidofovir provide conflicting results. Herein, we report the clinical, histological, and virological features of a liver transplant recipient successfully treated with a combined therapy of cidofovir and liposomal daunorubicin, associated with a reduction of the immunosuppressive regimen, for an advanced cutaneous and visceral KS.

Antibiotics, Antineoplastic↗

Cytosolic sialidase Neu2 upregulation during PC12 cells differentiation.

The cytosolic sialidase Neu2 is known to be involved in myoblast differentiation. Here, we observed a Neu2 transcriptional induction during nerve growth factor, fibroblast growth factor 2 and epidermal growth factor treatments of PC12 cells, a favored model to study neuronal differentiation. The expression analysis of Neu2 deleted promoter revealed a remarkable increase of luciferase activity in treated PC12 cells, suggesting that in this cell line the Neu2 transcriptional levels are highly regulated. The enzymatic activity of cytosolic sialidase Neu2 was found to increase transiently only during differentiation, whereas was undetectable in untreated PC12 cells. These data suggest a possible involvement of cytosolic sialidase Neu2 in differentiation of PC12 cells.

Animals↗

Overexpression of cytosolic sialidase Neu2 induces myoblast differentiation in C2C12 cells.

Cytosolic sialidase Neu2 has been implicated in myoblast differentiation. Here we observed a significant upregulation of Neu2 expression during differentiation of murine C2C12 myoblasts. This was evidenced both as an increase in Neu2 mRNA steady-state levels and in the cytosolic sialidase enzymatic activity. To understand the biological significance of Neu2 upregulation in myoblast differentiation, C2C12 cells were stably transfected with the rat cytosolic sialidase Neu2 cDNA. Neu2 overexpressing clones were characterized by a marked decrement of cell proliferation and by the capacity to undergo spontaneous myoblast differentiation also when maintained under standard growth conditions. This was evidenced by the formation of myogenin-positive myotubes and by a significant decrease in the nuclear levels of cyclin D1 protein. No differentiation was on the contrary observed in parental and mock-transfected cells under the same experimental conditions. The results indicate that Neu2 upregulation per se is sufficient to trigger myoblast differentiation in C2C12 cells.

Animals↗

The pipeline of new anticancer agents for breast cancer treatment in 2003.

In recent years, strategy in cancer therapy in general, and breast cancer in particular, has been the use of maximum tolerated doses of toxic non-specific agents as well as the investigation of a range of new agents that specifically target tumor-related molecules, in a variety of biological pathways. The trial of chemotherapy (CT) versus chemotherapy+trastuzumab (Herceptin) in HER-2-overexpressing metastatic breast cancer (MBC) was one of the first to use a biological agent in combination with chemotherapy with success and, together with some trials of taxanes in anthracycline-resistance patients one of the few to demonstrate an overall survival (OS) advantage in MBC. Five main molecular pathways are of particular interest in terms of new drug development in breast cancer: the estrogen receptor (ER) pathway, the tyrosine kinase signal transduction pathway, the cell cycle regulation pathway, the apoptosis pathway and the angiogenesis pathway. This review will focus on new agents, cytotoxic, hormonal and molecular-targeted, which are in advanced clinical stages of development for the treatment of MBC.

Antineoplastic Agents↗

Antioxidant potential and gap junction-mediated intercellular communication as early biological markers of mercuric chloride toxicity in the MDCK cell line.

In this study, the early nephrotoxic potential of mercuric chloride (HgCl(2)) has been evaluated in vitro, by exposing a renal-derived cell system, the tubular epithelial Madin-Darby canine kidney (MDCK) cell line, to the presence of increasing HgCl(2) concentrations (0.1-100 microM) for different periods of time (from 4 to 72 h). As possible biological markers of the tubular-specific toxicity of HgCl(2) in exposed-MDCK cultures we analysed: (i) critical biochemical parameters related to oxidative stress conditions and (ii) gap-junctional function (GJIC). HgCl(2) cytotoxicity was evaluated by cell-density assay. The biochemical analysis of the pro-oxidant properties of the mercuric ion (Hg(2+)) was performed by evaluating the effect of the metal salt on the antioxidant status of the MDCK cells. The cell glutathione (GSH) content and the activity of glutathione peroxidase (Gpx) and catalase (Cat), two enzymes engaged in the H(2)O(2) degradation, were quantified. HgCl(2) influence on MDCK GJIC was analysed by the microinjection/dye-transfer assay. HgCl(2)-induced morphological changes in MDCK cells were also taken into account. Our results, proving that subcytotoxic (0.1-10 microM) HgCl(2) concentrations affect either the antioxidant defences of MDCK cells or their GJIC, indicate these critical functions as suitable biological targets of early mercury-induced tubular cell injury.

Animals↗

HIV-1, HAART and bone metabolism.

Much attention has been paid to the emerging complications of HIV infection in patients receiving HAART. Recently, there emerged a potentially increased risk of bone problems like osteopenia, osteoporosis and osteonecrosis as patients live longer. It could be a drug side effect, a consequence of prolonged exposure to HIV and/or activated immune cells characteristic of HIV infection, or a consequence of immune system changes that accompany suppression of virus by the drugs. Future research should focus on the etiologic mechanisms, define the incidence and prevalence prospectively, determine the relationship with HAART (especially the rule of protease inhibitors), and help to guide management. Only when the mechanism for HIV-related versus HAART-related changes can be defined, will we be much closer to designing specific interventions.

Anti-HIV Agents↗

Independent lung ventilation in patients with unilateral pulmonary contusion. Monitoring with compliance and EtCO(2).

OBJECTIVE: a) to describe a non-barotraumatic ventilatory setting for independent lung ventilation (ILV); b) to determine the utility of single lung end-tidal CO(2) (EtCO(2)) monitoring to evaluate the ventilation to perfusion (V/Q) matching in each lung during ILV and for ILV weaning. DESIGN: prospective study. SETTING: general intensive care unit in a university teaching hospital. PATIENTS: twelve patients with unilateral thoracic trauma needing ILV. INTERVENTIONS AND RESULTS: ILV was started with each lung ventilated with the same tidal volume (Vt): plateau airway pressure (Pplat) was 34.2+/-3.2 cmH2O in diseased lungs (DL) and 18.1+/-1.9 cmH2O in normal lungs (NL) ( P<0.01). Static compliance (Cst) was 9.9+/-1.1 ml/cmH(2)O in DL and 19.3+/-1.7 ml/cmH(2)O in NL ( P<0.01). EtCO2 was 22.5+/-2.2 mmHg in DL and 36.6+/-1.9 mmHg in NL ( P<0.01). PaO(2)/FiO(2) was at 151+/-20. PEEP was applied on the DL and each lung was ventilated with a Vt that developed Pplat < or =26 cmH2O. With this setting, Vt given to the NL was unchanged, whereas it was reduced in the DL (238+/-30 ml vs 350+/-31 ml; P<0.01). Cst and EtCO2 were still significantly lower in the DL ( P<0.01, respectively), while the PaO(2)/FiO(2) ratio remained unchanged. Vt was then progressively increased in the DL as Pplat decreased, but remained unchanged in the NL. ILV was discontinued when Vt, Cst and EtCO(2) were the same in each lung. PaO(2)/FiO(2) ratio had then increased to 295+/-18. CONCLUSIONS: a) during ILV, adequate oxygenation and a reduction in V/Q mismatch can be obtained by setting Vt and PEEP to keep Pplat below a safe threshold for barotrauma; b) measurement of single lung EtCO2 can be useful to evaluate progressive V/Q matching.

Adult↗

Modulation of tumor angiogenesis by conditional expression of fibroblast growth factor-2 affects early but not established tumors.

Fibroblast growth factor-2 (FGF2) is a pleiotropic heparin-binding growth factor endowed with a potent angiogenic activity in vitro and in vivo. To investigate the impact of the modulation of FGF2 expression on the neovascularization at different stages of tumor growth, we generated stable transfectants (Tet-FGF2) from the human endometrial adenocarcinoma HEC-1-B cell line in which FGF2 expression is under the control of the tetracycline-responsive promoter (Tet-off system). After transfection, independent clones were obtained in which FGF2 mRNA and protein were up-regulated compared with parental cells. Also, the conditioned medium of Tet-FGF2 transfectants caused proliferation, urokinase-type plasminogen activator up-regulation, migration, and sprouting of cultured endothelial cells. A 3-day treatment of Tet-FGF2 cell cultures with tetracycline abolished FGF2 overexpression and the biological activity of the conditioned medium without affecting their proliferative capacity. Tet-FGF2 cells formed tumors when nude mice received s.c. injections. The administration of 2.0 mg/ml tetracycline in the drinking water before cell transplantation, continued throughout the whole experiment, inhibited FGF2 expression in Tet-FGF2 tumor lesions. This was paralleled by a significant decrease in the rate of tumor growth and vascularization to values similar to those observed in lesions generated by parental HEC-1-B cells. Tetracycline administration 20 days after tumor cell implant, although equally effective in reducing FGF2 expression and inhibiting tumor vascularity, only minimally impaired the growth of established Tet-FGF2 tumors. The results indicate that FGF2 expression deeply affects the initial tumor growth and neovascularization of HEC-1-B human endometrial adenocarcinoma in nude mice. On the contrary, the growth of established tumors appears to be independent of the inhibition of FGF2 expression and decreased vascular density. The possibility that a significant reduction of angiogenesis may not affect the progression of large tumors points to the use of antiangiogenic therapy in early tumor stage.

Adenocarcinoma↗

Assessment of respiratory system mechanics by artificial neural networks: an exploratory study.

We evaluated 1) the performance of an artificial neural network (ANN)-based technology in assessing the respiratory system resistance (Rrs) and compliance (Crs) in a porcine model of acute lung injury and 2) the possibility of using, for ANN training, signals coming from an electrical analog (EA) of the lung. Two differently experienced ANNs were compared. One ANN (ANN(BIO)) was trained on tracings recorded at different time points after the administration of oleic acid in 10 anesthetized and paralyzed pigs during constant-flow mechanical ventilation. A second ANN (ANN(MOD)) was trained on EA simulations. Both ANNs were evaluated prospectively on data coming from four different pigs. Linear regression between ANN output and manually computed mechanics showed a regression coefficient (R) of 0.98 for both ANNs in assessing Crs. On Rrs, ANN(BIO) showed a performance expressed by R = 0.40 and ANN(MOD) by R = 0.61. These results suggest that ANNs can learn to assess the respiratory system mechanics during mechanical ventilation but that the assessment of resistance and compliance by ANNs may require different approaches.

Animals↗

Role of gancyclovir and HAART administration in the treatment of a rare complication of HIV disease: cytomegalovirus-associated Guillain-Barré syndrome.

Peripheral nerve disorders are very common in patients with HIV infection, including inflammatory demyelinating polyneuropathies, such as Guillain-Barré syndrome. Causes of these neuropathies are probably multiple, and often dictated by the stage of the underlying HIV disease. Acute demyelinating polyneuropathy is usually preceded by infections, generally sustained by cytomegalovirus or Campylobacter jejuni, and a co-infection with HIV may represent the initial etiopathogenetic event leading to the neurological disorder. An extraordinary case report of a cytomegalovirus-associated Guillain-Barré syndrome occurred in one of our patients with advanced HIV infection, who was cured by gancyclovir and HAART administration, and gives us the opportunity to briefly discuss the intriguing pathogenetic and clinical correlations among HIV disease, cytomegalovirus infection, this neurological syndrome, and its specific treatment.

Adult↗

Examining new models for the study of autocrine and paracrine mechanisms of angiogenesis through FGF2-transfected endothelial and tumour cells.

Angiogenesis is the process of generating new capillary blood vessels. Uncontrolled endothelial cell proliferation is observed in tumour neovascularization. Several growth factors and cytokines have been shown to stimulate endothelial cell proliferation in vitro and in vivo and among them FGF2 was one of the first to be characterised. FGF2 is a Mr 18,000 heparin-binding cationic polypeptide that induces proliferation, migration, and protease production in endothelial cells in culture and neovascularization in vivo. FGF2 interacts with endothelial cells through two distinct classes of receptors, the high affinity tyrosine-kinase receptors (FGFRs) and low affinity heparan sulfate proteoglycans (HSPGs) present on the cell surface and in the extracellular matrix. Besides experimental evidence for paracrine mode of action for FGF2, some observations raise the hypothesis that FGF2 may also play an autocrine role in endothelial cells. FGF2 may therefore represent a target for anti-angiogenic therapies. In order to assess the angiostatic potential of different classes of compounds, novel experimental models have been developed based on the autocrine and/or the paracrine capacity of FGF2.

Angiogenesis Inhibitors↗

Schedule specific biochemical modulation of 5-fluorouracil in advanced colorectal cancer: a randomized study. GISCAD, IOR and collaborating centers.

BACKGROUND: We have recently suggested that bolus 5-fluorouracil (5-FU) may work via a RNA directed mechanism while continuous infusion 5-FU may kill cells via a thymidylate synthase related pathway. It may thus be possible to selectively modulate each schedule biochemically. We have compared an alternating regimen of bolus and continuous infusion 5-FU, selectively modulated for the schedule of administration, with modulated bolus 5-FU in advanced colorectal cancer patients. PATIENTS AND METHODS: Two hundred fourteen patients from nineteen Italian centers were randomized to the control arm consisting of biweekly cycles of MTX, 200 mg/m2 on day 1, followed by bolus 5-FU 600 mg/m2 on day 2 and 6-S-leucovorin rescue, or to the experimental arm consisting of two biweekly cycles of the same regimen as in the control arm alternated to three weeks of continuous infusion 5-FU (200 mg/m2 day) + weekly bolus 6-S-leucovorin, 20 mg/m2. RESULTS: Nine CR and twenty-seven PR were obtained on one hundred eleven evaluable patients treated in experimental arm (RR = 32%, 95% confidence interval (95% CI): 24%-42%), while two CR and eleven PR were observed among one hundred three evaluable patients in control arm (RR = 13%, 95% CI: 7%-21%). WHO grade 3-4 toxicity occurred in 13% of cycles of experimental arm and in 8% of cycles in control arm. The PFS was significantly longer in experimental arm (6.2 vs. 4.3 months, odds ratio 0.66, P = 0.003), while the overall survival was similar in both arms (14.8 months in experimental arm vs. 14.1 months in control arm); quality of life was similar as well. Eighty percent of patients receiving second-line chemotherapy in control arm were treated with continuous infusion 5-FU. CONCLUSIONS: Alternating, schedule-specific biochemical modulation of FU is more active than MTX --> 5-FU as first-line treatment of advanced colorectal cancer. However, the overall survival was similar suggesting that alternating bolus and infusional 5-FU upfront may be as effective as giving them in sequence as first- and second-line treatment.

Adult↗

Thrombospondin-1/HIV-1 tat protein interaction: modulation of the biological activity of extracellular Tat.

Tat protein, a trans-activating factor of the human immunodeficiency virus type 1, acts also as an extracellular molecule modulating gene expression, cell survival, growth, transformation, and angiogenesis. Here we demonstrate that human thrombospondin-1 (TSP), a plasma glycoprotein and constituent of the extracellular matrix, binds to glutathione-S-transferase (GST)-Tat protein but not to GST. Scatchard plot analysis of the binding of free GST-Tat to immobilized TSP reveals a high-affinity interaction (Kd equal to 25 nM). Accordingly, TSP inhibits cell internalization and HIV-1 LTR trans-activating activity of extracellular Tat in HL3T1 cells with ID50 equal to 10-30 nM. Also, TSP inhibits cell interaction and mitogenic activity of extracellular Tat in T53 Tat-less cells. TSP is instead ineffective when administered after the interaction of Tat with cell surface heparan-sulfate proteoglycans has occurred, in keeping with its ability to prevent but not disrupt Tat/heparin interaction in vitro. Finally, TSP inhibits the autocrine loop of stimulation exerted by endogenous Tat in parental T53 cells. Accordingly, TSP overexpression inhibits cell proliferation, angiogenic activity, and tumorigenic capacity of stable T53 transfectants. Our data demonstrate the ability of TSP to bind to Tat protein and to affect its LTR trans-activating, mitogenic, angiogenic, and tumorigenic activity. These findings suggest that TSP may be implicated in the progression of AIDS and in AIDS-associated pathologies by modulating the bioavailability and biological activity of extracellular Tat.

Adenocarcinoma↗

[A rare case of popliteal pterygium syndrome].

The PPS (Popliteal Pterygium Syndrome) is a rare malformative syndrome, with autosomal dominant inheritance and variable penetrance, but always reduced. Sporadic cases also are reported. The ethiopatogenesis is unknown. The principal hypothesis is a arrest of development of parts based upon an imbalance between mesodermal migration and ectodermal proliferation. It dont appear relationships with race or sex. It is a syndrome of three polarity: orofacial, muscles-skeletonlike, genito-urinary. The Authors report a case and show the therapeutic procedures and the future program. The diagnosis, especially differential, is difficult for a lot of incomplete forms. Any of the Authors do diagnosis in according with Escobar, with the identification at least of three principal signs.

Female↗

Human erythropoietin induces a pro-angiogenic phenotype in cultured endothelial cells and stimulates neovascularization in vivo.

Hematopoietic and endothelial cell lineages share common progenitors. Accordingly, cytokines formerly thought to be specific for the hematopoietic system have been shown to affect several functions in endothelial cells, including angiogenesis. In this study, we investigated the angiogenic potential of erythropoietin (Epo), the main hormone regulating proliferation, differentiation, and survival of erythroid cells. Epo receptors (EpoRs) have been identified in the human EA.hy926 endothelial cell line by Western blot analysis. Also, recombinant human Epo (rHuEpo) stimulates Janus Kinase-2 (JAK-2) phosphorylation, cell proliferation, and matrix metalloproteinase-2 (MMP-2) production in EA.hy926 cells and significantly enhances their differentiation into vascular structures when seeded on Matrigel. In vivo, rHuEpo induces a potent angiogenic response in the chick embryo chorioallantoic membrane (CAM). Accordingly, endothelial cells of the CAM vasculature express EpoRs, as shown by immunostaining with an anti-EpoR antibody. The angiogenic response of CAM blood vessels to rHuEpo was comparable to that elicited by the prototypic angiogenic cytokine basic fibroblast growth factor (FGF2), it occurred in the absence of a significant mononuclear cell infiltrate, and it was not mimicked by endothelin-1 (ET-1) treatment. Taken together, these data demonstrate the ability of Epo to interact directly with endothelial cells and to elicit an angiogenic response in vitro and in vivo and thus act as a bona fide direct angiogenic factor.

Allantois↗

Time-course of impairment of respiratory mechanics after cardiac surgery and cardiopulmonary bypass.

OBJECTIVE: Cardiopulmonary bypass (CPB) is associated with abnormalities of lung function characterized by an increase in static elastance of the respiratory system. We examined the following: a) the effects of CPB on the total inspiratory volume-pressure (V-P) relationship of the respiratory system; b) the relative contribution of the chest wall and lung to the impairment of respiratory system mechanics; and c) the time-course of such impairment. DESIGN: Prospective, interventional study. SETTING: Surgical and medical intensive care units in a teaching hospital. PATIENTS: Eight adult patients scheduled for elective open heart surgery to correct valvular dysfunction. INTERVENTIONS: V-P curves (interrupter technique) of the respiratory system were partitioned between the chest wall and lung by measurements of esophageal pressure. Measurements were obtained before sternotomy (control), immediately after, 4 hrs after, and 7 hrs after separation from CPB. MEASUREMENTS AND MAIN RESULTS: Control V-P relationships of the respiratory system and lung showed lower inflection points (Pflex) at pressure values of 5.9+/-2.3 and 4.3+/-2.5 cm H2O, respectively. Immediately after and 4 hrs after separation from CPB, both curves had sigmoid shapes because of lower Pflex and formation of upper inflection (UIP) points. The pressures corresponding to the Pflex increased significantly (p < .001) by 56%+/-3% and 78%+/-4%, whereas the UIP corresponded to a pressure value of 42.34+/-8.5 and 35.6+/-7.8 cm H2O in the respiratory system and lung, respectively. A linear V-P relationship of the chest wall was observed during the control condition and after separation from CPB. Four hours later, no further increases in the pressure values corresponding to Pflex were observed on the inspiratory V-P curves of the respiratory system and lung, whereas the UIP occurred at a pressure of 35.6+/-9.1 and 29.7+/-8.4 cm H2O, respectively. A UIP was present on the V-P curve of the chest wall at a volume of 0.77+/-0.02 L. Seven hours after separation from CPB, the inspiratory V-P curves of the respiratory system, chest wall, and lung returned to normal. CONCLUSIONS: Sternotomy and CPB produced immediate changes in lung mechanics. Chest wall mechanics were affected only 4 hrs after sternotomy. Seven hours after disconnection from CPB, all mechanics had returned to normal.

Adult↗

Role of endothelial cell extracellular signal-regulated kinase1/2 in urokinase-type plasminogen activator upregulation and in vitro angiogenesis by fibroblast growth factor-2.

Downstream signaling triggered by the binding of fibroblast growth factor-2 (FGF2) to its tyrosine-kinase receptors involves the activation of mitogen-activated protein kinase kinase (MEK) with consequent phosphorylation of extracellular signal-regulated kinases (ERKs). Here we demonstrate that FGF2 induces ERK1/2 activation in bovine aortic endothelial (BAE) cells and that the continuous presence of the growth factor is required for sustained ERK1/2 phosphorylation. This is prevented by the MEK inhibitors PD 098059 and U0126, which also inhibit FGF2-mediated upregulation of urokinase-type plasminogen activator (uPA) and in vitro formation of capillary-like structures in three-dimensional type I collagen gel. Various FGF2 mutants originated by deletion or substitution of basic amino acid residues in the amino terminus or in the carboxyl terminus of FGF2 retained the capacity to induce a long-lasting activation of ERK1/2 in BAE cells. Among them, K128Q/R129Q-FGF2 was also able to stimulate uPA production and morphogenesis whereas R129Q/K134Q-FGF2 caused uPA upregulation only. In contrast, K27, 30Q/R31Q-FGF2, K128Q/K138Q-FGF2 and R118,129Q/K119,128Q-FGF2 exerted a significant uPA-inducing and morphogenic activity in an ERK1/2-dependent manner only in the presence of heparin. Furthermore, no uPA upregulation and morphogenesis was observed in BAE cells treated with the deletion mutant (delta)27-32-FGF2 even in the presence of soluble heparin. Thus, mutational analysis of FGF2 dissociates the capacity of the growth factor to induce a persistent activation of ERK1/2 from its ability to stimulate uPA upregulation and/or in vitro angiogenesis. In conclusion, the data indicate that ERK1/2 phosphorylation is a key step in the signal transduction pathway switched on by FGF2 in endothelial cells. Nevertheless, a sustained ERK1/2 activation is not sufficient to trigger uPA upregulation and morphogenesis. FGF2 mutants may represent useful tools to dissect the signal transduction pathway(s) mediating the complex response elicited by an angiogenic stimulus in endothelial cells.

Amino Acid Sequence↗