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Biomedical subjects

P Gentilini

Publications and source records attributed to P Gentilini.

At least 37 records · Page 2Linked to original sources
PubMed2000

Ligands of peroxisome proliferator-activated receptor gamma modulate profibrogenic and proinflammatory actions in hepatic stellate cells.

BACKGROUND & AIMS: Proliferation and migration of hepatic stellate cells (HSCs) and expression of chemokines are involved in the pathogenesis of liver inflammation and fibrogenesis. Peroxisome proliferator-activated receptor (PPAR)-gamma is a receptor transcription factor that controls growth and differentiation in different tissues. We explored the effects of PPAR-gamma agonists on the biological actions of cultured human HSCs. METHODS: HSCs were isolated from normal human liver tissue and used in their myofibroblast-like phenotype or immediately after isolation. Activation of PPAR-gamma was induced with 15-deoxy-Delta(12, 14)-prostaglandin J(2) or with troglitazone. RESULTS: PPAR-gamma agonists dose-dependently inhibited HSC proliferation and chemotaxis induced by platelet-derived growth factor. This effect was independent of changes in postreceptor signaling or expression of c-fos and c-myc and was associated with inhibition of cell cycle progression beyond the G(1) phase. Activation of PPAR-gamma also resulted in a complete inhibition of the expression of monocyte chemotactic protein 1 at the gene and protein levels. Comparison of quiescent and culture-activated HSCs revealed a marked decrease in PPAR-gamma expression in activated cells. CONCLUSIONS: Activation of PPAR-gamma modulates profibrogenic and proinflammatory actions in HSCs. Reduced PPAR-gamma expression may contribute to confer an activated phenotype to HSCs.

Antineoplastic Agents↗
PubMed2000

Randomized trial of fludarabine versus fludarabine and idarubicin as frontline treatment in patients with indolent or mantle-cell lymphoma.

PURPOSE: A first comparative trial of fludarabine (FLU) alone versus FLU plus idarubicin (FLU-ID) for indolent or mantle-cell lymphomas. PATIENTS AND METHODS: From September 1995 to July 1998, 199 patients aged 25 to 65 years (median, 54 years) with newly diagnosed stages II to IV indolent or mantle-cell lymphomas (standard risk according to the International Prognostic Index) were enrolled onto a multicenter, 1:1 randomized study. Of the 199 patients who were able to be assessed, 101 were assigned to the FLU group (six monthly cycles of FLU 25 mg/m(2)/d on days 1 through 5) and 98 to the FLU-ID group (six monthly cycles of FLU 25 mg/m(2)/d on days 1 through 3 and idarubicin 12 mg/m(2) on day 1). RESULTS: In the FLU group, complete response (CR) and partial response rates were 47% and 37%, respectively, whereas in the FLU-ID group, they were 39% and 42%, respectively. In-depth analysis of the CR rate with respect to histologic type showed that FLU seemed to be superior to FLU-ID in treating follicular lymphomas (60% v 40%, respectively), whereas FLU-ID seemed to be more effective than FLU in treating nonfollicular lymphomas (small lymphocytic, 43% v 29%, respectively; immunocytoma, 38% v 23%, respectively; P = not significant), excluding the mantle-cell subset (in which there was no difference between the two groups). No striking differences were observed between the two protocols in terms of overall response or toxicity, which was generally mild. However, with a median follow-up of 19 months, only 29 patients (62%) who received FLU alone have maintained their initial CR, compared with 32 (84%) of those who received FLU-ID therapy (P =.021). CONCLUSION: Although the FLU-ID regimen may not significantly improve the induction of CR in most indolent-lymphoma patients, our preliminary data do suggest that, with respect to FLU alone, it may be capable of conferring a longer-lasting CR and that it might be superior in terms of CR rate in small lymphocytic and immunocytoma subtypes.

Adult↗
PubMed1999

Elderly aggressive-histology non-Hodgkin's lymphoma: first-line VNCOP-B regimen experience on 350 patients.

Age is a risk factor and a prognostic parameter in elderly aggressive-histology non-Hodgkin's lymphoma (NHL) patients. Several adapted chemotherapeutic regimens have recently been designed and tested on elderly patients. Several of these trials have shown that older aggressive-histology NHL patients can benefit from specific and adequate treatment capable of curing a percentage of these patients. Between January 1992 and September 1997, 350 previously untreated aggressive-histology NHL patients greater than 60 years of age were treated with a combination therapy including cyclophosphamide, mitoxantrone, vincristine, etoposide, bleomycin, and prednisone (VNCOP-B). Complete remission (CR) was achieved by 202 (58%) patients and partial remission (PR) by 87 (25%), whereas the remaining 61 (17%) patients were nonresponders. The overall response rate (CR + PR) was 83%. Clinical and hematologic toxicities were modest, because 71% of the patients received granulocyte colony-stimulating factor (G-CSF). The CR rates for the three age groups (60 to 69, 70 to 79, and >/=80 years) were similar: 61%, 59%, and 56%, respectively. At 5 years, the relapse-free survival rate was 65%, the overall survival rate was 49%, and the failure-free survival rate was 33%. In the multivariate analysis, prognostic factors associated with longer survival or longer relapse-free survival turned out to be localized disease stage (P =.001) and good performance status (P =.0002). Application of the International Prognostic Factor Index was significantly associated with outcome (P =.001). These data confirm on a large cohort of patients that the VNCOP-B regimen is effective in inducing good CR and relapse-free survival rates with only moderate toxic effects in elderly aggressive-histology NHL.

Aged↗
PubMed1999

Monocyte chemotactic protein-1 as a chemoattractant for human hepatic stellate cells.

Following liver injury, hepatic stellate cells (HSC) undergo proliferation and migrate into damaged areas in response to chemotactic factors. HSC have been shown to regulate leukocyte trafficking by secreting monocyte chemotactic protein-1 (MCP-1), a chemokine that recruits monocytes and lymphocytes. In this study, we explored whether MCP-1 exerts biological actions on HSC. HSC were isolated from normal human livers, cultured on plastic, and studied in their myofibroblast-like phenotype, and three different cells lines were used. Chemotaxis was measured in modified Boyden chambers. Phosphatidylinositol 3-kinase (PI 3-K) was assayed on phosphotyrosine immunoprecipitates. Exposure of HSC to MCP-1 stimulated migration of HSC in a dose-dependent fashion. Maximal stimulation was obtained with 250 ng/mL MCP-1, which resulted in a 3- to 4-fold stimulation of cell migration. Checkerboard analysis showed that the increase in cell migration was almost completely a result of chemotaxis rather than chemokinesis. In contrast, in quiescent HSC, MCP-1 did not exert any effect on cell migration. In leukocytes, MCP-1 activates the pertussis toxin-sensitive CCR2 receptor. However, transcripts for CCR2 could not be shown in HSC, and pertussis toxin only modestly inhibited MCP-1-induced migration. Exposure of HSC to MCP-1 was associated with an increase in cytosolic calcium concentration, PI 3-K activity, protein tyrosine phosphorylation. Blocking calcium influx or pretreatment of HSC with the PI 3-K inhibitor wortmannin markedly reduced cell migration. This study shows, for the first time, a potential direct profibrogenic action of MCP-1 via HSC chemotaxis. MCP-1-dependent signals in these cells are not transduced by CCR2 and may be mediated by alternative chemokine receptors. (HEPATOLOGY 1999;29:140-148.)

Blotting, Western↗
PubMed1999

Extracellular signal-regulated kinase activation differentially regulates platelet-derived growth factor's actions in hepatic stellate cells, and is induced by in vivo liver injury in the rat.

Upon liver injury, hepatic stellate cells (HSC) show increased proliferation, motility, and extracellular matrix (ECM) production. The extracellular signal-regulated kinases (ERK) control different functions in a cell-specific manner. In this study, we evaluated the role of ERK activation in cultured HSC stimulated with platelet-derived growth factor (PDGF) and after induction of liver injury in vivo. HSC were isolated from normal human liver tissue, cultured on plastic, and used in their myofibroblast-like phenotype. In in vivo experiments, HSC were isolated from normal rats or at different time points after a single intragastric administration of CCl(4). Nontoxic concentrations of PD98059, a specific inhibitor of ERK activation, reduced PDGF-induced activation of ERK in a dose-dependent fashion. Suppression of ERK activation was associated with complete inhibition of HSC proliferation and with a 57% reduction in chemotaxis. In the presence of the ERK inhibitor, binding of the AP-1 complex and of STAT1 to the related regulatory elements was inhibited. The inhibition of the DNA binding activity of STAT1 was mediated by a reduction in PDGF-induced tyrosine phosphorylation. Expression of c-fos in response to PDGF was also reduced, but not suppressed, by treatment with PD98059. In HSC isolated from CCl(4)-treated rats, ERK activity increased as early as 6 hours following liver damage, and declined thereafter. The results of this study indicate that ERK activation regulates proliferation and chemotaxis of HSC, and modulates nuclear signaling. Acute liver damage in vivo leads to activation of ERK in HSC.

Animals↗
PubMed1999

Prevalence of mixed infection by different hepatitis C virus genotypes in patients with hepatitis C virus-related chronic liver disease.

Multiple infection by different hepatitis C virus (HCV) genotypes may be of great clinico-pathologic interest. In this study we determined the effective prevalence of coinfections by two or more HCV genotypes in 213 subjects with HCV-positive chronic hepatitis by using genotype-specific polymerase chain reaction (PCR), genotype-specific probe hybridization, and direct sequencing. The most prevalent genotype was HCV-1b (54%). HCV-2 (a/c) was also prevalent (27%), and types 1a and 3a were found in 5% and 3% of patients, respectively. A mixed infection was detected in 23 patients (10.8%): 4 out of 23 were coinfected by types 1a + 1b, while the remaining 19 patients had a b + 2 (a/c) mixed infection. Further analysis based on restriction fragment length polymorphism (RFLP) on type-specific PCR products was used to verify genotyping results. Only four coinfections (1a + 1b in 2 patients and 1b + 2 (a/c) in the remaining 2 patients, respectively) were confirmed by enzyme cleavage. All patients with true coinfection had long-lasting infection and liver cirrhosis. Both true and false mixed infections resulting from RFLP analysis were confirmed by direct sequencing of type-specific amplification products. We also determined a recurrent C/T transversion at position 618 in all sequenced samples. In 4 cases another point mutation (G/A at position 626) was found, reducing the number of mismatches between HCV-2 and HCV-1b from 4 to 3 (or 2). Interestingly, all HCV-2 isolates sequenced showed the highest degree of nucleotide homology with HCV-2 subtype c, confirming the relatively high prevalence of this subtype in Italy. In conclusion, we showed the possibility of multiple infection by different HCV types in the general population of chronically infected patients without particular risk factors, even if in a low percentage of cases. Further studies are needed to assess the clinical relevance of chronic HCV infection with multiple genotypes.

Adult↗
PubMed1999

Cardiovascular and renal function in normotensive and hypertensive patients with compensated cirrhosis: effects of posture.

BACKGROUND/AIMS: The aim of this study was to evaluate cardiovascular and renal function in patients with compensated cirrhosis and essential hypertension in the supine position and in response to standing up. METHODS: Twenty-four patients with compensated cirrhosis (12 with elevated arterial pressure) and 20 healthy volunteers underwent echocardiographic evaluation of left ventricular end-diastolic and stroke volumes, ejection fraction, cardiac index, arterial pressure, peripheral resistance, creatinine clearance and sodium excretion in both the supine and the standing position. RESULTS: When supine, only normotensive patients had a hyperdynamic circulation, with increased left ventricular end-diastolic and stroke volumes, cardiac index, and ejection fraction, and reduced peripheral resistance. Creatinine clearance and sodium excretion were comparable in patients and controls. Standing induced a decrease in end-diastolic volume in all subjects. Healthy volunteers maintained cardiovascular homeostasis by increasing ejection fraction and heart rate, while both normotensive and hypertensive cirrhotic patients experienced a fall in stroke volume and cardiac index, despite a marked activation of the renin-aldosterone and sympathetic nervous system. Creatinine clearance decreased only in normotensive patients, who experienced the greatest reduction in sodium excretion. CONCLUSIONS: Compensated cirrhotic patients with arterial hypertension had no evidence of hyperdynamic circulation. Like their normotensive counterparts, hypertensive patients had an impaired cardiovascular response to the postural challenge, but a lesser degree of renal dysfunction during standing.

Aged↗
PubMed1999

Albumin improves the response to diuretics in patients with cirrhosis and ascites: results of a randomized, controlled trial.

BACKGROUND/AIMS: Diuretic treatment of ascites could result in intravascular volume depletion, electrolyte imbalance and renal impairment. We investigated whether intravascular volume expansion with albumin exert beneficial effects in cirrhosis with ascites. METHODS: In protocol 1, 126 cirrhotic inpatients in whom ascites was not relieved following bed rest and a low-sodium diet, were randomly assigned to receive diuretics (group A) or diuretics plus albumin, 12.5 g/day (group B). In protocol 2, group A patients continued to receive diuretics and group B diuretics plus albumin (25 g/week) as outpatients and were followed up for 3 years. End points were: disappearance of ascites, duration of hospital stay (protocol 1), recurrence of ascites, hospital readmission and survival (protocol 2). RESULTS: The cumulative rate of response to diuretic treatment of ascites was higher (p < 0.05) and hospital stay was shorter (20 +/- 1 versus 24 +/- 2 days, p < 0.05) in group B than in group A patients. After discharge, group B patients had a lower cumulative probability of developing ascites (19%, 56%, 69% versus 30%, 79% and 82% at 12, 24 and 36 months, p < 0.02) and a lower probability of readmission to the hospital (15%, 56%, 69% versus 27%, 74% and 79%, respectively, p < 0.02). Survival was similar in the two groups. CONCLUSIONS: Albumin is effective in improving the rate of response and preventing recurrence of ascites in cirrhotic patients with ascites receiving diuretics. However, the cost/benefit ratio was favorable to albumin in protocol 1 but not in protocol 2.

Adult↗
PubMed1999

Biology of hepatic stellate cells and their possible relevance in the pathogenesis of portal hypertension in cirrhosis.

In the past 10 years we have witnessed an exponential increase in the knowledge on the development and progression of liver fibrosis. At present, liver fibrogenesis is referred to as a dynamic process involving complex cellular and molecular mechanisms, resulting from the chronic activation of the tissue repair mechanisms that follows reiterated liver tissue injury. The identification and characterization of the cell types and of the different mediators involved in this process has allowed a "revisitation" of several issues related to liver cirrhosis and its immediate consequences. Among these, evaluation of the relationships occurring between fibrogenesis and portal hypertension, cholestasis, and the development of hepatocellular carcinoma represent some of the hottest areas of research in the field of hepatology. Our aim is to establish a link between the available knowledge on the biology of hepatic stellate cells and their possible implication in the genesis and progression of portal hypertension.

Animals↗
PubMed1999

Hepatorenal syndrome and its treatment today.

The pathogenesis of ascites, a severe and the most frequent complication during cirrhosis, is still not completely understood, but present evidence indicates that portal hypertension principally triggers renal sodium and water retention. Ascites is associated with profound disturbances of splanchnic and systemic haemodynamics, which in turn may influence renal function. Within the kidney the balance between vasoconstricting and vasodilating factors is critical for the maintenance of renal function. As the disease progresses, vasoconstricting factors (mainly angiotensin II, catecholamines, thromboxane, leucotrienes and endothelins) prevail, probably due to the exhaustion of the vasodilating renal autacoid system (mainly prostaglandins). In this setting, vasoconstriction of the intrarenal vascular system induces marked and often irreversible sodium and water retention, leading to refractory ascites, a progressive rise in plasma creatinine levels and reduction of renal clearances (hepatorenal syndrome, HRS). This persistent renal hypoxia may also favour the occurrence of tubular damage due to several causes. A careful therapeutic approach is first based on sequential diuretic treatment (and the addition of adequate plasma expansion with human albumin for patients with diuretic resistant ascites), which may lead to control of ascites for years. However, when HRS occurs, all the proposed treatments (such as paracentesis, administration of renal vasodilators, systemic vasoconstrictors, calcium channel antagonists, TIPS, surgical portosystemic shunts) have been shown to moderately or temporarily improve renal function only, leaving liver transplantation as the only choice of treatment for patients.

Angiotensin II↗
PubMed1999

Nongastrointestinal low-grade mucosa-associated lymphoid tissue lymphoma: analysis of 75 patients.

PURPOSE: Nongastrointestinal locations represent about 30% to 40% of all low-grade mucosa-associated lymphoid tissue (MALT) lymphomas. We report a retrospective analysis of 75 patients with nongastrointestinal low-grade MALT lymphoma, presenting their clinical, therapeutic, and follow-up data with respect to the initial location of the lymphoma. PATIENTS AND METHODS: From January 1988 to October 1997, 75 patients with untreated nongastrointestinal low-grade MALT lymphoma were subjected to treatments ranging from local radiotherapy and local interferon alfa administration to chemotherapy. The lymphomas were located in the lung (19 patients), orbital soft tissue (16 patients), skin (seven patients), thyroid (seven patients), lachrymal gland (six patients), conjunctiva (six patients), salivary gland (six patients), breast (three patients), eyelid (two patients), larynx (one patient), bone marrow (one patient), and trachea (one patient). RESULTS: Complete and partial remissions were achieved in 59 (79%) and 16 (21%) of the 75 patients, respectively, with an overall response rate of 100%. All but two of the patients are still alive, with a median follow-up of 47 months; these two patients died from other causes. The estimated time to treatment failure rate is 30% at 5 years. In the thyroid and lachrymal gland sites, no relapses were reported. CONCLUSION: Our data regarding the largest reported series of nongastrointestinal MALT lymphomas confirm the good prognosis of this particular clinicopathologic entity and the significant efficacy of different therapeutic approaches to specific sites.

Adult↗
PubMed1999

Expression of monocyte chemotactic protein-1 precedes monocyte recruitment in a rat model of acute liver injury, and is modulated by vitamin E.

BACKGROUND: Increased expression of monocyte chemotactic protein-1 (MCP-1) has been indicated as a mechanism underlying leukocyte recruitment after liver injury. In this study we examined the temporal relationship between MCP-1 expression and the appearance of monocyte infiltration during acute liver injury. In addition, we tested the effects of vitamin E, a well known antioxidant, on these parameters. Rats were intoxicated with a single intragastric administration of CCl4 with or without pretreatment with vitamin E (atocopherol). METHODS: Monocyte chemotactic protein-1 expression was analyzed by northern blotting and in situ hybridization and monocyte infiltration was determined by ED-1 immunostaining. The results were quantitated by computerized image analysis. Expression of MCP-1 mRNA was significantly increased as early as 12 hours following injury, and progressively increased thereafter. In contrast, a significant increase in the number of ED-1 positive cells, an index of monocyte infiltration, was observed only 24 and 48 hours after injury. RESULTS: Vitamin E markedly reduced MCP-1 expression at the mRNA and protein levels, and caused a significant reduction in the number of monocyte/macrophages, indicating a role for oxidative stress in the induction of MCP-1 expression in vivo. Accordingly, in cultured hepatic stellate cells, different oxidative stress-related molecules increased MCP-1 mRNA. CONCLUSIONS: These data suggest the existence of a direct relationship between MCP-1 expression and monocyte infiltration after acute liver injury, and that preventing the generation of oxidative stress-related molecules results in decreased expression and release of this chemokine.

Animals↗
PubMed1999

Fludarabine-based chemotherapy in untreated mantle cell lymphomas: an encouraging experience in 29 patients.

BACKGROUND AND OBJECTIVE: A prospective study to evaluate the role of fludarabine alone or in combination with idarubicin in untreated patients with mantle cell lymphoma (MCL). DESIGN AND METHODS: Twenty-nine untreated patients with mantle cell lymphoma were stochastically treated with intravenous fludarabine at a dose of 25 mg/m(2)/day for 5 days (11 patients) or with a combination of fludarabine and idarubicin (FLU-ID) (fludarabine 25 mg/m(2) i.v. on days 1 to 3 and idarubicin 12 mg/m(2) i.v. on day 1 (18 patients). For both regimens, cycles were given at three-week intervals for a total of six courses. According to the International Prognostic Index, the most part of high-intermediate and high risk factor patients were in the FLU-ID subset: 7 (39%) patients vs. 2 (18%) in the fludarabine alone subset. RESULTS: Of the 29 patients, 8 (28%) obtained a complete response and 10 (35%) a partial response, with an overall response rate of 63%. The remaining 11 (37%) patients did not respond to the therapy. The overall response rates were 64% (7 patients) in the fludarabine group and 61% (11 patients) in the FLU-ID group. The complete response rate was 27% (3 patients) for fludarabine and 28% (5 patients) for FLU-ID. The toxicity was mild in terms of neutropenia and infections, and no fatalities occurred due to drug-induced side effects. INTERPRETATION AND CONCLUSIONS: These results suggest the efficacy of fludarabine alone or in combination with idarubicin in MCL patients. It will be important to increase this experience and to assess other fludarabine-containing regimens, in particular with cyclophosphamide plus idarubicin and with mitoxantrone and or cyclophosphamide, to test the true role of this approach in MCL.

Adult↗
PubMed1998

HNE interacts directly with JNK isoforms in human hepatic stellate cells.

4-Hydroxy-2,3-nonenal (HNE) is an aldehydic end product of lipid peroxidation which has been detected in vivo in clinical and experimental conditions of chronic liver damage. HNE has been shown to stimulate procollagen type I gene expression and synthesis in human hepatic stellate cells (hHSC) which are known to play a key role in liver fibrosis. In this study we investigated the molecular mechanisms underlying HNE actions in cultured hHSC. HNE, at doses compatible with those detected in vivo, lead to an early generation of nuclear HNE-protein adducts of 46, 54, and 66 kD, respectively, as revealed by using a monoclonal antibody specific for HNE-histidine adducts. This observation is related to the lack of crucial HNE-metabolizing enzymatic activities in hHSC. Kinetics of appearance of these nuclear adducts suggested translocation of cytosolic proteins. The p46 and p54 isoforms of c-Jun amino-terminal kinase (JNKs) were identified as HNE targets and were activated by this aldehyde. A biphasic increase in AP-1 DNA binding activity, associated with increased mRNA levels of c-jun, was also observed in response to HNE. HNE did not affect the Ras/ERK pathway, c-fos expression, DNA synthesis, or NF-kappaB binding. This study identifies a novel mechanism linking oxidative stress to nuclear signaling in hHSC. This mechanism is not based on redox sensors and is stimulated by concentrations of HNE compatible with those detected in vivo, and thus may be relevant during chronic liver diseases.

Aldehydes↗
PubMed1998

Expression of the thrombin receptor in human liver: up-regulation during acute and chronic injury.

Thrombin is generated during tissue damage in several organs, including the liver, and participates in the process of tissue repair through proteolytic activation of a specific thrombin receptor (TR). The aim of this study was to investigate TR expression in human liver by immunohistochemistry and in situ hybridization. In normal liver, immunostaining for TR was present in the endothelial lining of the hepatic sinusoids. During chronic hepatitis, several cells expressing the TR were detected in the inflammatory infiltrate of portal tracts. In cirrhosis with chronic active hepatitis, expression of the TR was also present in mesenchymal cells of fibrous septa. TR expression was markedly up-regulated during fulminant hepatitis, with the highest expression in mesenchymal cells in areas of regeneration. Up-regulation of TR expression was associated with increased levels of TR messenger RNA (mRNA), as assessed by in situ hybridization and RNAse protection assay of liver RNA. Immunostaining of serial sections using specific cellular markers showed that different nonparenchymal cells contribute to TR expression during liver injury. TR expression was also shown in cultured human hepatic stellate cells, with increasing signal comparing activated versus quiescent cells. Because thrombin is rapidly generated after tissue damage, regulated TR expression may be involved in tissue remodeling and/or scarring during liver damage.

Acute Disease↗