Biomedical subjects

G Squadrito

Publications and source records attributed to G Squadrito.

At least 55 records · Page 3Linked to original sources

PubMed1997

Hepatitis C virus genome complexity correlates with response to interferon therapy: a study in French patients with chronic hepatitis C.

Recent studies performed in Japan have suggested that hepatitis C virus (HCV) genome heterogeneity might be taken as a predictive virological parameter of response to interferon alfa (IFN-alpha) treatment. However, there is presently no information on the impact of this virological parameter in patients from Western countries infected by different HCV genotypes. We have investigated this issue by using amplification of HCV E2 hypervariable region 1, followed by single-strand conformation polymorphism assay (PCR-SSCP). We have studied 95 French patients infected with various genotypes and treated with IFN-alpha-2b. We analyzed the impact of the following parameters by univariate and multivariate analyses: HCV heterogeneity, HCV genotype, viral load, and liver histology in response to therapy. Age >40 years (P < .01), viral load >35 x 10(5) Eq/mL (P < .01), genotype 1 (P < .01), and a number of SSCP bands >3 (P < .001) were significantly associated with nonresponse or relapse; cirrhosis was associated with nonresponse. In multivariate analysis, three variables were independently associated with the absence of long-term response: SSCP bands >3, genotype 1, and viral load >35 x 10(5) with odds ratios of 19, 7.5, and 11.8, respectively. Our data establish the major importance of HCV genome heterogeneity in patients infected with both HCV types associated with low (genotype 1b) or high (genotype 3a) response to IFN-alpha.

Adult↗

PubMed1997

The effects of recombinant human granulocyte-colony stimulating factor on vascular dysfunction and splanchnic ischaemia-reperfusion injury.

1. The aim of our study was to investigate the effects of recombinant human granulocyte-colony stimulating factor in a rat model of splanchnic ischaemia-reperfusion injury. 2. Male anaesthetized rats were subjected to clamping of the splanchnic arteries for 45 min. This surgical procedure resulted in an irreversible state of shock (splanchnic artery occlusion shock. SAO shock). Sham operated animals were used as controls. Survival rate, serum tumour necrosis factor-alpha (TNF-alpha), neutrophil count, bone marrow myeloid precursor cells, myeloperoxidase activity (MPO; studied as a quantitative means to assess leukocyte accumulation), mean arterial blood pressure and the responsiveness of aortic rings to phenylephrine (PE, 1 nM-10 microM) were studied. 3. SAO shocked rats had a decreased survival rate (0% at 4 h of reperfusion, while sham shocked rats survived more than 4 h), increased serum levels of TNF-alpha (201 +/- 10 u ml-1; sham shocked rats = undetectable), neutropenia, enhanced MPO activity in the ileum (0.11 +/- 0.06 u x 10(-3) g-1 tissue; sham shocked rats = 0.02 +/- 0.001 u x 10(-3) g-1 tissue) and in the lung (1.5 +/- 0.2 u x 10(-3) g-1 tissue; sham shocked rats = 0.19 +/- 0.05 u x 10(-3) g-1 tissue) and unchanged bone marrow myeloid precursor cells. Furthermore aortic rings from shocked rats showed a marked hyporeactivity to PE. 4. Administration of recombinant human granulocyte colony stimulating factor (rh G-CSF; 5, 10 and 20 micrograms kg-1 5 min following the release of occlusion) increased in a dose-dependent manner survival rate (90% at 4 h of reperfusion with the dose of 20 u x 10(-3) g kg-1), reduced serum TNF-alpha (13 +/- 5 u ml-1) and MPO activity in the ileum (0.065 +/- 0.002 u x 10(-3) g-1 tissue) and in the lung (0.7 +/- 0.03 microgram kg-1 tissue), improved neutropenia and mean arterial blood pressure but did not modify bone marrow myeloid progenitor cells. Furthermore rh G-CSF, either in vivo or in vitro (200 nM for 1 h in the organ bath), restored to control values the hyporeactivity to PE. Finally rh G-CSF potently inhibited the activity of inducible nitric oxide synthase in peritoneal macrophages activated with endotoxin. 5. Our results suggest that rh G-CSF protects against splanchnic ischaemia reperfusion injury by a mechanism(s) that does not depend upon its haematopoietic effects.

Animals↗

PubMed1997

The involvement of tumour necrosis factor-alpha in the protective effects of 17 beta oestradiol in splanchnic ischaemia-reperfusion injury.

1. Tumour necrosis factor-alpha (TNF-alpha) is a cytokine that is implicated in the pathogenesis of ischaemic states and atherosclerosis. We tested the hypothesis that the vasoprotective effects of the oestrogens may be mediated in vivo by inhibition of the formation of TNF-alpha. 2. Anaesthetized rats, subjected to total occlusion of the superior mesenteric artery and the coeliac trunk for 45 min developed a severe shock state resulting in a fatal outcome within 75-90 min after the release of occlusion. Sham-operated animals were used as controls. 3. Splanchnic artery occlusion (SAO) shocked rats had a marked hypotension, enhanced levels of TNF-alpha in serum and macrophages, leukopenia and increased ileal leukocyte accumulation, studied by means of myeloperoxidase activity (MPO). Furthermore, aortae from SAO rats showed a marked hyporeactivity to phenylephrine (PE, 1 nM-10 microM), reduced responsiveness to acetylcholine (ACh, 10 nM-10 microM) and an increased staining for intercellular adhesion molecule-1 (ICAM-1). 4. In vivo administration of 17 beta oestradiol (500 micrograms kg-1, i.m., three hours before the induction of SAO) increased survival rate (100%, 4 h after SAO), enhanced mean arterial blood pressure; reduced serum TNF-alpha (25 +/- 5 u ml-1 vs 379 +/- 16 u ml-1), ameliorated leukopaenia and reduced ileal MPO (0.7 +/- 0.02 u 10(-3) g-1 tissue vs 4.2 +/- 0.4 u 10(-3) g-1 tissue). Furthermore aortae from SAO rats treated with 17 beta oestradiol exhibited a greater contractile response to phenylephrine, improved responsiveness to ACh and a blunted staining of ICAM-1. Finally 17 beta oestradiol, added in vitro to peritoneal macrophages collected from untreated SAO rats, significantly reduced TNF-alpha production. 5. Our results suggest that inhibition of TNF-alpha in vivo may explain, at least in part, the vasoprotective effects of oestrogens.

Animals↗

PubMed1997

Mutations in the nonstructural 5A region of hepatitis C virus and response of chronic hepatitis C to interferon alfa.

BACKGROUND & AIMS: Mutations in hepatitis C virus (HCV) nonstructural protein 5A (NS5A) may correlate with response to interferon in Japanese patients with chronic hepatitis C. The aim of this study was to examine whether these findings could be expanded to European patients infected with genotypes associated to low (1b) or high (3a) response rates. METHODS: Pretreatment serum samples of 66 patients with chronic HCV infection, 48 infected with genotype 1b and 18 with 3a, were analyzed. RESULTS: Among patients infected with genotype 3a, 1 of 7 long-term responders and none of 11 nonresponders showed NS5A amino acid mutations. Among patients infected with genotype 1b, all 7 long-term responders, but also 27 of 41 nonresponders, showed NS5A mutations. There was no correlation between number of mutations and response to therapy. In 10 patients, sequences obtained before and after treatment were compared and failed to show any change. Serum HCV RNA levels did not differ between patients with and without mutations in NS5A sequence. CONCLUSIONS: No significant correlation was found in patients infected with genotypes 1b or 3a between NS5A sequence and response to interferon alfa. NS5A mutations do not correlate with viral load. Changes in this region were not found during interferon alfa treatment.

Adult↗

PubMed1997

Antioxidant activity of U-83836E, a second generation lazaroid, during myocardial ischemia/reperfusion injury.

The 21-aminosteroid compounds are potent lipid peroxidation inhibitors belonging to a new class of antioxidants given the collective name of "lazaroids". They protect cells from oxidative damage induced by oxygen-based free radicals in a variety of in vitro and in vivo test systems. U-83836E is one of the second-generation lazaroids that are based on a non steroidal structure characterized by a ring portion of alpha-tocopherol bonded with various amine groups. We investigated the ability of U-83836E to reduce myocardial damage in rats undergoing left coronary artery occlusion for 60 min followed by 6 hours of reperfusion. This ischemia/reperfusion model produced wide heart necrosis, membrane lipid peroxidation, ventricular arrhythmias, tissue neutrophil infiltration and a marked decrease in endogenous antioxidants. Intravenous administration of U-83836E, (7.5, 15 and 30 mg/kg) at onset of reperfusion, reduced myocardial necrosis, expressed as a percentage of either the area at risk or the total left ventricle (p < 0.001), improved haemodynamic conditions by decreasing ventricular arrhythmias (p < 0.005), limited membrane lipid peroxidation (evaluated by assessing conjugated dienes, p < 0.001; and 4-hydroxynonenal, p < 0.001) restored the endogenous antioxidants vitamin E (p < 0.001), and superoxide dismutase (pt < 0.001). Furthermore, the lazaroid inhibited the derimental hydroxyl radical formation (p < 0.001), evaluated indirectly by a trapping agent and reduced heart neutrophil infiltration, measured by testing cardiac tissue elastase (p < 0.001) that is released from the stimulated granulocytes at the site of injury. These data suggest that this compound could be a new useful tool to study the mechanisms of oxidative damage during myocardial infarction.

Aldehydes↗

PubMed1996

Leukocyte integrin very late antigen-4/vascular cell adhesion molecule-1 adhesion pathway in splanchnic artery occlusion shock.

We investigated the role played by the very late antigen-4 (VLA-4)/ vascular cell adhesion molecule-1 (VCAM-1) interaction in the pathogenesis of splanchnic artery occlusion shock. Splanchnic artery occlusion shock was induced in anaesthetized rats by clamping splanchnic arteries for 45 min. Sham operated animals were used as controls. Survival time, serum tumour necrosis factor (TNF-alpha), monocyte and lymphocyte cell count and the responsiveness to acetylcholine of aortic rings were studied. Furthermore we investigated the VCAM-1 expression on vessel endothelium and the percentage of VLA-4 positive leukocytes. Splanchnic artery occlusion shocked rats had a decreased survival time (76 +/- 10 min, while sham shocked rats survived more than 4 h), increased serum levels of TNF-alpha (328 +/- 11 U/ml), a decreased number of both monocytes and lymphocytes and reduced responsiveness to acetylcholine (10 nM-10 microM) of aortic rings. In addition we found an increased expression of endothelial VCAM-1 on aortic rings and a reduced percentage of VLA-4 positive lymphocytes and monocytes. Passive immunization with specific antibodies raised against either VCAM-1 or VLA-4 (2 mg/kg, i.v., 3 h before splanchnic artery occlusion shock) increased survival, improved monocyte and lymphocyte count and restored the responsiveness of aortic rings to acetylcholine (P < 0.01). Finally, inhibition of TNF-alpha biosynthesis reversed the increased endothelial expression of VCAM-1 and the reduced percentage of integrin VLA-4 positive leukocytes. Our findings suggest that (i) VLA-4/VCAM-1 interaction has a role in the pathogenesis of circulatory shock; (ii) this interaction might be a target for new therapeutic approaches to the therapy of low-flow states.

Acetylcholine↗

PubMed1996

Endotoxin tolerance impairs a pertussis-toxin-sensitive G-protein regulating tumour necrosis factor release by macrophages from tumour-bearing rats.

The aim of this work was to study whether a G-protein regulates lipopolysaccharide (LPS) induced TNF-alpha production in tumour-bearing rat peritoneal macrophages differently to in normal rats. We also investigated whether a state of 'early endotoxin tolerance' affects LPS induced TNF-alpha release via a G-protein-mediated phenomenon. LPS-stimulated (50 micrograms ml-1 of Salmonella enteritidis LPS) TNF-alpha release was investigated in peritoneal macrophages harvested from both normal rats and tumour-bearing rats. Cholera toxin (10, 100 and 1000 ng ml-1) did not significantly modify LPS-induced TNF-alpha release. In contrast pertussis toxin (0.1, 1.0 and 10 ng ml-1) significantly increased LPS-induced TNF-alpha release and inhibited LPS-stimulated prostaglandin E2 (PGE2) production in both normal rat macrophages and tumour-bearing rat macrophages. Pertussis toxin effects on these LPS responses were correlated with a pertussis-toxin-mediated ADP-ribosylation of a 41 kDa protein(s). The LPS-mediated responses were significantly greater in macrophages from tumour-bearing rats than in macrophages from normal rats. PGE2 (10(-9), 10(-8) and 10(-7) M) suppressed LPS-induced TNF-alpha production in a dose-dependent fashion. A state of 'early endotoxin tolerance' was then induced in tumour-bearing rats by a single intravenous injection of 125 micrograms rat-1 of LPS, and experiments were performed on peritoneal macrophages harvested 24 h after LPS injection. In tolerant macrophages pertussis toxin induced an increase in LPS-stimulated TNF-alpha release and an inhibition in LPS-stimulated PGE2 release significantly lower than in macrophages harvested from non-tolerant tumour bearing rats. Our results suggest that a pertussis-toxin-sensitive G-protein may serve to regulate the synthesis of TNF-alpha in rat peritoneal macrophages and that the activity of this pertussis-sensitive G-protein is increased in macrophages from tumour-bearing rats. Furthermore, our experiments would indicate that a 'state of endotoxin tolerance', caused by altering the function of presumably a Gi-protein, may exert beneficial effects on the functions of macrophages in tumour-bearing rats.

Adenosine Diphosphate Ribose↗

PubMed1996

Monocytes and lymphocytes as active participants in the pathogenesis of experimental shock.

We investigated the role played by monocytes and lymphocytes in the pathogenesis of experimental shock. Splanchnic artery occlusion (SAO) shock was induced in anaesthetized rats by clamping splanchnic arteries for 45 min followed by reperfusion. Sham operated animals were used as controls. SAO shocked rats had a decreased survival time (80 +/- 11 min, while sham shocked rats survived more than 4 h), increased serum (248 +/- 21 U/ml) and macrophage (145 +/- 15 U/ml) levels of TNF-alpha, enhanced myeloperoxidase (MPO) activity in the ileum (3.38 +/- 0.2 U x 10(-3)/g tissue), decreased number of monocytes, lymphocytes and neutrophils and a profound hypotension. In addition we found an increased expression of vascular cell adhesion molecule-1 (VCAM-1) on aortic endothelium and a reduced percentage of VLA-4 positive monocytes and lymphocytes. Inhibition of TNF-alpha synthesis, reversed the increased endothelial expression of VCAM-1, increased the percentage of integrin VLA-4 positive leukocytes and improved monocyte, lymphocyte and neutrophil count. Furthermore a passive immunization with specific antibodies raised against VCAM-1 (2 mg/kg, i.v. 3 h before SAO) increased survival, reduced MPO activity in the ileum (0.034 +/- 0.04 U x 10(-3)/g tissue) and improved mean arterial blood pressure. Our data suggest that monocytes and lymphocytes participate in the pathogenesis of splanchnic ischaemia-reperfusion injury and may amplify the adhesion of neutrophils to peripheral tissues.

Animals↗

PubMed1996

Thrombolytic therapy with urokinase reduces increased circulating endothelial adhesion molecules in acute myocardial infarction.

The aim was to investigate circulating E-selectin and Intercellular Adhesion Molecule-1 (ICAM-1) in acute myocardial infarction. Our study was carried out in 80 patients, 40 hospitalized for acute myocardial infarction (AMI), 20 suffering from chronic stable angina and 20 healthy control subjects. Samples of venous blood were taken from all patients at the moment of hospitalization and after 2, 4, 6, 8, 10, 12 and 24 hours from the thrombolytic treatment (AMI + urokinase) or conventional therapy (AMI + nitroglycerin), for the dosage of creatinine kinase (CK) and adhesion molecules. The CK was determined by means of a Hitachi 901 automatic analyser using an enzymatic method (reagents Boheringer-Biochemia, Germany). Soluble E-selectin (sE-selectin) and soluble ICAM-1 (sICAM-1) were measured in the serum using a specific immunoassay (British Biotechnology Products). The serum levels of Tumor Necrosis Factor (TNF-alpha) were evaluated using an immunoenzymatic assay to quantitate the serum levels of the cytokine (British Biotechnology Products). Patients with acute myocardial infarction (AMI) had increased serum levels of soluble E-selectin (sE-selectin; AMI + urokinase = 312 +/- 20 ng/ml; AMI + nitroglycerin = 334 +/- 15 ng/ml) and soluble ICAM-1 (sICAM-1; AMI + urokinase = 629 +/- 30 ng/ml; AMI + nitroglycerin = 655 +/- 25 ng/ml) compared to both patients with chronic angina (sE-selectin = 67 +/- 10 ng/ml; sICAM-1 = 230 +/- 20 ng/ml) and healthy control subjects (sE-selectin = 53 +/- 15 ng/ml; sICAM-1 200 +/- 16 ng/ml). Furthermore patients with acute myocardial infarction also had increased serum levels of Tumor Necrosis Factor (TNF-alpha = 309 +/- 10 pg/ml; control subjects = 13 +/- 5 pg/ml). Thrombolytic therapy with urokinase (1,000,000 IU as an intravenous bolus for 5 minutes, followed by an infusion of an additional 1,000,000 IU for the following two hours) succeeded in producing reperfusion and reduced the serum levels of sE-selectin (52 +/- 13 ng/ml) and sICAM-1 (202 +/- 31 ng/ml). In contrast patients not eligible for thrombolytic therapy and therefore treated with conventional therapy (a continuous i.v. infusion of nitroglycerin at the dose of 50 mg/die) did not show any significant reduction in both sE-selectin and sICAM-1 throughout the study. Our results confirm previous experimental data and indicate that adhesion mechanisms supporting leukocyte-endothelium interaction may also be operative in human acute myocardial infarction.

Adult↗

PubMed1996

Effects of S-ethylisothiourea, a potent inhibitor of nitric oxide synthase, alone or in combination with a nitric oxide donor in splanchnic artery occlusion shock.

1. The aim of this study was to compare the effects of an intravenous infusion of a potent and non selective nitric oxide synthase inhibitor S-ethylisothiourea (Ethyl-TU) with that of a nitric oxide (NO) donor on the pathological sequelae associated with splanchnic artery occlusion (SAO) shock. In addition the effects of the combination of these two treatments were also investigated. 2. SAO shock was induced in anaesthetized rats by clamping splanchnic arteries for 45 min. Sham operated animals were used as controls. Survival time, white blood cell (WBC) count, mean arterial blood pressure, myeloperoxidase activity (MPO; studied as a quantitative means to evaluate neutrophil accumulation) and the responsiveness of aortic rings to acetylcholine (ACh, 10 nM-10 microM) and to phenylephrine (PE, 1 nM-10 microM) were studied. 3. SAO shocked rats had a decreased survival rate (0% survival 2 h after the release of occlusion) and survival time (76 +/- 10 min), increased MPO activity in the ileum (3.39 +/- 0.8 u x 10(-3) g-1 tissue), a marked leukopenia and a profound hypotension. In addition aortic rings from shocked rats showed a marked hyporeactivity to PE and reduced responsiveness to ACh. Endothelium denuded aortic rings had also a marked hyporeactivity to PE. 4. In vivo administration of Ethyl-TU (0.1 mg kg-1 h-1, beginning 1 min after the onset of reperfusion) significantly increased survival time and rate, improved mean arterial blood pressure, restored the responsiveness to PE, but did not change MPO activity, leukopenia or the impairment in the responsiveness of aortic rings to ACh. Addition of Ethyl-TU (2 microM) to endothelium denuded aortic rings in vitro, restored the marked hyporeactivity to PE. Administration of the NO donor C87-3754 (0.75 mg kg-1 h-1, beginning 1 min after the onset of reperfusion) slightly increased survival time and reduced MPO activity and leukopenia, but did not change survival rate and mean arterial blood pressure. In addition C87-3754 restored the responsiveness of aortic rings to ACh to control values, but did not modify the hyporeactivity to PE. The combination of these two interventions produced a higher degree of protection than either Ethyl-TU or C87-3754 alone. In fact, co-administration of Ethyl-TU plus C87-3754 completely prevented mortality, reduced MPO activity, attenuated leukopenia and the profound hypotension and restored the impaired responsiveness of aortic rings to PE and ACh. 5. Our study suggests that treatment with a nitric oxide synthase inhibitor combined with an NO donor may be a new therapeutic approach to the treatment of splanchnic artery occlusion shock.

Acetylcholine↗

PubMed1996

Effects of cloricromene on the levels of endothelin and on the microcirculatory function in peripheral atherosclerotic arteriopathies.

The effects of cloricromene on plasma endothelin-1 (ET-1) levels and on microcirculatory function in 9 patients with peripheral atherosclerotic arteriopathy (PAA) and in healthy control subjects were studied. ET-1 levels and microcirculatory function were evaluated both under basal conditions and 30, 60, and 90 min after acute administration of cloricromene (30 mg i.v.). PAA patients had significantly increased levels of ET-1 and impaired vascular parameters (studied by means of Winsor's Index, Gosling's Index, postischemic perfusion index and recovery time) when compared to control subjects. The acute administration of cloricromene (30 mg i.v.) did not change plasma ET-1 both in control subjects and in patients with PAA. In contrast, cloricromene produced a significant improvement in the postischemic perfusion index and in recovery time in arteriopathic patients. Control subjects and patients with PAA also underwent a cold pressor test (CPT) under basal conditions and (72 h later) 30 min after an acute intravenous administration of cloricromene (30 mg i.v.). CPT caused a higher increase in ET-1 in the patients with PAA compared to the control group, and a reduction in the vascular flow at the femoral level, while the pretreatment with cloricromene prevented both the increase in the levels of ET-1 and the reduction of the femoral vascular flow observed after the cold stimulus in patients with PAA. Our data show that cloricromene, besides ameliorating the microcirculatory function, is able to interfere with dynamic mechanisms, such as those induced by the CPT, capable of stimulating the release of ET-1 at the vascular level.

Aged↗

PubMed1996

Protection of ischemic and reperfused rat myocardium by the nonglucocorticoid 21-aminosteroid U-74389G, a new inhibitor of lipid peroxidation.

We studied the effects of the aminosteroid U-74389G (21-[4-(2, 6-di-1-pyrrolidinyl-4-pyrimidinyl)-1-piperazinyl]-pregna-1,4,9(11)- triene-3,20-dione(2)-2-butenenedionate), a putative inhibitor of lipid peroxidation, which protects the rat myocardium after ischemia and reperfusion. Pentobarbital-anesthetized (50 mg/kg) rats were subjected to 60 min of occlusion of the left main coronary artery followed by 60 min of reperfusion. Myocardial ischemia/reperfusion produced a large cardiac necrosis (81 +/- 8.6% of the area at risk and 65 +/- 14.8% of the total left ventricle), polymorphonuclear infiltration in the jeopardized tissue (myeloperoxidase activity = 4.2 +/- 2.1 U X 10(-3)/g tissue in the area at risk and 7.0 +/- 3.6 U X 10(-3)/g tissue in the necrotic area), hydroxyl radical (OH.) formation (0.55 +/- 0.16 nmol/ml), increased plasma malonylaldehyde (40.2 +/- 3.9 nmol/ml) and lactate dehydrogenase (431 +/- 30 mIU/ml) and caused a decrease in the survival rate. Treatment with U-74389G (15 and 30 mg/kg i.v.) at the onset of reperfusion caused a reduction of necrotic area expressed as a percentage of either the area at risk (76 +/-7.4% with 15 mg/kg and 69 +/- 13.5% with 30 mg/kg; P < .05) or the total left ventricle (53 +/- 13.6% with 15 mg/kg and 46 +/- 16.8% with 30 mg/kg; P < .05). Treatment U-74389G reduced the myeloperoxidase activity, evaluated as an index of neutrophil infiltration, both in the area at risk (2.7 +/- 1.1 and 2.2 +/- 1.7 U X 10(-3)/g tissue with the doses of 15 and 30 mg/kg, respectively; P < .05) and in the necrotic area (4.3 +/- 2.4 and 3.8 +/- 2.9 U X 10(-3)/g tissue with 15 and 30 mg/kg, respectively; P < .05); decreased OH. formation (measured indirectly by the administration of the trapping agent salicylic acid); and analyzing the hydroxylation product 2,5-dihydroxybenzoic acid during reperfusion (0.35 +/- 0.12 and 0.32 +/- 0.15 nmol/ml with the doses of 15 and 30 mg/kg, respectively; P < .005). Treatment inhibited lipid peroxidation by blunting plasma malonylaldehyde (26.7 +/- 3.1 and 20.8 +/- 3.3 with the doses of 15 and 30 mg/kg, respectively; P < .001), prevented cellular disruption by reducing the increase of plasma lactate dehydrogenase (288.6 +/- 28 and 201.3 +/- 16 mIU/ml with the doses of 15 and 30 mg/kg, respectively; P < .001). Finally, U-74389G enhanced the survival rate evaluated at the end of the experiment (from 40 to 87%). These outcomes suggest that the drug may have potential for cardioprotective use in acute myocardial infarction.

Animals↗

PubMed1995

G 619, a dual thromboxane synthase inhibitor and thromboxane A2 receptor antagonist, inhibits tumor necrosis factor-alpha biosynthesis.

G 619 is 3-carbamyl-(3'-picolyl)-4-methoxy-1-benzamide. The compound is structurally related to picotamide, a previously reported dual thromboxane synthase inhibitor/thromboxane A2 receptor antagonist, which displays inhibitory activity on tumor necrosis factor-alpha. The aim of the present work was to study the effect of G 619 on tumor necrosis factor-alpha synthesis both in vivo and in vitro. Salmonella enteritidis lipopolysaccharide was used to induce tumor necrosis factor-alpha production. Septic shock was produced in male rats by a single intravenous (i.v.) injection of 20 mg/kg (LD90) of Salmonella enteritidis lipopolysaccharide. Rats were pretreated with G 619 (50 mg/kg, i.v.) or vehicle (1 ml/kg, i.v.) 1 h before endotoxin challenge. Salmonella enteritidis lipopolysaccharide administration dramatically reduced survival rate (0%, 72 h after endotoxin administration), reduced mean arterial blood pressure, increased plasma levels of thromboxane B2 and 6-keto-prostaglandin F1 alpha and enhanced serum levels of tumor necrosis factor. Furthermore, endotoxic shock produced characteristic gastric damage, consisting of haemorrhagic infiltrates. Pretreatment with G 619 in vivo significantly protected against Salmonella enteritidis lipopolysaccharide-induced lethality (80% survival rate and 60% survival rate 24 h and 72 h after Salmonella enteritidis lipopolysaccharide injection, respectively), reduced hypotension, decreased plasma thromboxane B2 and serum tumor necrosis factor-alpha levels and enhanced blood levels of 6-keto-prostaglandin F1 alpha. In rat peritoneal macrophages, G 619 in vitro (25, 50 and 100 microM) significantly blunted (P < 0.001) Salmonella enteritidis lipopolysaccharide-stimulated production of tumor necrosis factor-alpha, whereas it increased 6-keto-prostaglandin F1 alpha and cyclic AMP levels. The present data indicate that G 619 may be useful during disease states characterized by elevated tumor necrosis factor-alpha levels.

6-Ketoprostaglandin F1 alpha↗

PubMed1995

E-selectin involvement in the pathogenesis of splanchnic artery occlusion shock.

We investigated the involvement of E-selectin in the pathogenesis of splanchnic artery occlusion shock. Splanchnic artery occlusion shock was induced in anaesthetized rats by clamping splanchnic arteries for 45 min. Sham-operated animals were used as controls. Survival time, serum tumor necrosis factor-alpha, while blood cell count, mean arterial blood pressure and myeloperoxidase activity were determined. Splanchnic artery occlusion-shocked rats had a decreased survival time (85 +/- 8 min, while sham-shocked rats survived more than 4 h), reduced mean arterial blood pressure, increased serum levels of tumor necrosis factor-alpha (186 +/- 9 U/ml) and myeloperoxidase activity in the ileum (0.10 +/- 0.04 U x 10(-3)/g tissue) and in the lung (1.5 +/- 0.06 U x 10(-3)/g tissue). Shocked rats showed histological alterations in the ileum and in the lung. Administration of a hyperimmune serum containing specific antibodies raised against E-selectin significantly increased survival time (225 +/- 10 min), reduced leukopenia and myeloperoxidase activity both in the ileum (0.035 +/- 0.001 U x 10(-3)/g tissue) and in the lung (0.3 +/- 0.005 U x 10(-3)/g tissue), improved the cardiovascular changes and reduced the histological alterations in the ileum and lung. Our data are consistent with an involvement of E-selectin in the pathogenesis of splanchnic artery occlusion shock.

Animals↗

PubMed1995

Apolipoprotein AI-CIII-AIV genetic polymorphisms and coronary heart disease in type 2 diabetes mellitus.

The aim of this study was to verify whether or not the increased prevalence of coronary heart disease (CHD) commonly observed in patients with type 2 diabetes mellitus is related to a genetic background involving restriction fragment length polymorphisms (RFLPs) of apolipoproteins. On the basis of a case-control design, 62 type 2 diabetic patients with CHD (confirmed by clinical history and electrocardiogram) and 62 age- and sex-matched diabetic subjects without CHD were enrolled. In each of them RFLPs of the apolipoprotein CIII gene (S1 or S2 allele) and AI promoter region (A or G allele), together with fasting plasma lipids and apolipoproteins levels, were assessed. The rare S2 allele was found significantly (P = 0.05) more frequently in patients with CHD, and its related S1S2 genotype was associated with higher plasma levels of total cholesterol (P = 0.01), triglycerides (P = 0.007) and apo B (P = 0.001) than the S1S1 genotype. The A allele was more frequent (P = 0.004) in patients without CHD and was associated with lower plasma cholesterol (P = 0.0001), low-density lipoprotein (LDL)-cholesterol (P = 0.0001) and apo B (P = 0.005). The S1/A haplotype was more frequent (P = 0.05) in patients without CHD and was associated with the lowest plasma lipid levels. These results suggest that genetic factors, related to the apo AI-CIII-AIV gene cluster, could play a role in the development of CHD in type 2 diabetic patients, probably through modification of their plasma lipid pattern.

Alleles↗

PubMed1995

Tumour necrosis factor mediates E-selectin production and leukocyte accumulation in myocardial ischaemia-reperfusion injury.

The aim of our study was to examine the mechanism of E-selectin production and leukocyte accumulation in myocardial ischaemia-reperfusion injury. Myocardial injury was induced in anaesthetized rats by the clamping of the left main coronary artery followed by reperfusion. After thoracotomy a silk suture was placed under the left coronary artery. The ligature was tied for a period of 1 h and after this period it was untied and the ischaemic myocardium was reperfused for 1 h (MI/R rats) or removed (SHAM MI/R rats). Myocardial ischaemia plus reperfusion in untreated rats decreased survival rate, produced a marked myocardial necrosis, enhanced cardiac myeloperoxidase activity (a marker enzyme commonly used to assess polymorphonuclear leukocyte infiltration) and increased serum creatinephosphokinase (CPK) activity, serum levels of tumour necrosis factor-alpha (TNF-alpha) and serum levels of soluble E-selectin (sE-selectin). Furthermore, MI/R rats had an increased pressure rate index studied as a quantitative means for assessing myocardial oxygen demand. Administration of cloricromene, an inhibitor of TNF-alpha, reduced TNF-alpha production, significantly lowered serum sE-selectin levels, blunted leukocyte accumulation in the ischaemic myocardium and protected the myocardium from injury due to ischaemia and reperfusion. The results of the present study show an involvement of E-selectin in vivo in the pathogenesis of myocardial ischaemia and reperfusion and suggest that TNF-alpha may induce in vivo the production of a specific adhesion mechanism which sustains leukocyte infiltration.

Animals↗

PubMed1995

Hepatitis B E antigen detection in formalin-fixed liver biopsy specimens. A tool to investigate wild-type and E-minus variant HBV infection.

The aim of this study is to investigate whether hepatitis B e antigen (HBeAg) reactivity can be detected on formalin-fixed, paraffin-embedded liver tissue, and whether immunohistochemical detection of intrahepatic HBeAg may help to distinguish between "wild-type" and "eminus" hepatitis B virus (HBV) infection. Liver biopsy specimens were analyzed from 27 patients with chronic type B hepatitis: 12 patients had serum HBeAg (group A), and 15 patients were anti-HBe positive (group B). Part of each biopsy fragment was processed for histologic and immunohistochemical studies, and a part was used for HBV-DNA analysis. Dewaxed sections from each specimen were tested with a specific monoclonal anti-HBe antibody; then a Biotin-Streptavidin kit was used as detection system. HBeAg was revealed in 10 of 12 cases of group A and in 6 of the 15 cases of group B. Pre-core region of HBV genomes, isolated from each biopsy specimen, was analyzed by direct sequencing: 10 cases of group A were found to be infected by wild-type HBV alone and 2 cases by both wild and e-minus HBV types. In group B, all the 6 cases with intrahepatic HBeAg reactivity were found to be infected by mixed viral population, whereas the 9 cases negative for such reactivity were found to be infected by e-minus HBV alone. These results show that HBeAg can be detected in formalin-fixed, paraffin-embedded liver specimens, and the method is sensitive and specific. Because the presence of HBeAg in the liver indicates a wild-type HBV infection, and the lack of detection of such antigen in the hepatocytes of anti-HBe positive subjects correlates with unmixed e-minus HBV infection, the authors conclude that this technique is a useful tool for recognizing the viral strains that infect patients with chronic type B hepatitis.

Adolescent↗

PubMed1995

Improved survival and reversal of endothelial dysfunction by the 21-aminosteroid, U-74389G in splanchnic ischaemia-reperfusion injury in the rat.

1. Anaesthetized rats subjected to total occlusion of the superior mesenteric artery and the coeliac trunk for 45 min developed a severe shock state (splanchnic artery occlusion, SAO shock) resulting in death within 70-90 min after release of the occlusion. Sham-operated animals were used as controls. 2. Survival rate, survival time, serum tumour necrosis factor (TNF-alpha), white blood cell (WBC) count, mean arterial blood pressure (MAP), plasma malonyladehyde (MAL); myeloperoxidase activity (MPO) and the responsiveness to acetylcholine (ACh 10 nM-10 microM) of aortic rings were investigated. 3. SAO shocked rats had a decreased survival rate and survival time (74 +/- 10 min, while sham-shocked rats survived more than 4 h), reduced mean arterial blood pressure, increased serum levels of TNF-alpha (267 +/- 13 u ml-1) and plasma levels of MAL (57 +/- 7 nmol ml-1), enhanced MPO activity in the ileum (0.23 +/- 0.04 u x 10(-3) g-1 tissue) and in the lung (2.2 +/- 0.8 u x 10(-3) g-1 tissue), leukopenia and reduced responsiveness to ACh of aortic rings. 4. The 21-aminosteroid U-74389G (30 mg kg-1, i.v.) increased survival (survival time = 232 +/- 15 min), lowered the serum levels of TNF-alpha and the plasma levels of MAL, reduced leukopenia and MPO activity both in the ileum (0.021 +/- 0.004 u x 10(-3) g-1 tissue) and in the lung (0.23 +/- 0.03 u x 10(-3) g-1 tissue), improved MAP and restored the responsiveness to ACh of aortic rings. 5. Our data suggest that U-74389G is a potent lipid peroxidation inhibitor and that it has antishock and endothelial protective actions.

Acetylcholine↗