Regulation of splanchnic perfusion

In splanchnic arteries, vasodilators decrease the cytosolic free calcium concentration ([Ca(2+)]i) by inducing Ca(2+)sequestration and extrusion, by limiting the entry of extracellular Ca(2+)via L-type Ca(2+)channels and by decreasing the agonist-induced mobilization of intracellular Ca(2+). Cyclic GMP kinase and membrane hyperpolarization are important mediators of the decrease in [Ca(2+)]i. Vasoconstrictors increase [Ca(2+)]i by mobilizing intracellular Ca(2+)from the sarcoplasmic reticulum and by stimulating extracellular Ca(2+)entry via L-type Ca(2+)channels. Activation of G proteins, inositol trisphosphate, diacylglycerol and membrane depolarization are important mediators of the increase in [Ca(2+)]i.     

Hepatitis C virus genotype 5: epidemiological characteristics and sensitivity to combination therapy with interferon-alpha plus ribavirin

Twenty-six patients living in the Midi-Pyrenees region of France who were infected with hepatitis C virus (HCV) genotype 5 were investigated. Most of these patients were of advanced age and had been infected nosocomially or by blood transfusion. Our case-control study, in which we treated patients with interferon- alpha plus ribavirin, indicated that, 24 weeks after the beginning of treatment, the virus response in patients infected with HCV genotype 5 was better than that in patients infected with HCV genotype 1 (100% of patients negative for detectable HCV RNA vs. 36.3%, respectively; P < .01); furthermore, 48 weeks after the end of treatment, the virus response in patients infected with HCV genotype 5 was better than that in patients infected with HCV genotype 1 (63.6% vs. 22.7%, respectively; P < .05) and was similar to that in patients infected with HCV genotype 2 or 3 (66.6%). These results show that HCV genotype 5 might have good intrinsic sensitivity to combination therapy with interferon- alpha plus ribavirin.     

Age trend in hepatitis C virus genotype distribution as seen in a Brussels teaching hospital

The hepatitis C virus genotype distribution was studied among age groups in 501 referred patients with chronic hepatitis C by INNO-LiPA HCV II (Innogenetics, Belgium). Ten patients had coinfection with several genotypes. Two hundred seventy of 491 singly infected individuals (57%) had 1b, 66 (13.4%) 3a, 57 (11.6%) 1a. HCV subtype 1b was predominant but its prevalence increased with age (76.5% of patients born in the '20s, 39.3% in the '70s) (P < 0.0001). Three possibilities could explain the shift towards a wider variety of genotypes in younger age. (1) 1b could be the original subtypes in this population, (2) the non-1b subtypes could give less chronic carriers, (3) the non-1b subtypes could have a higher mortality, which seems improbable. The 1b genotype seems the oldest subtype in our country while others were imported later through increased population movements and changing habits.     

A pilot study of 220 mg/m2 melphalan followed by autologous stem cell transplantation in patients with advanced haematological malignancies: pharmacokinetics and toxicity

We studied the pharmacokinetics and toxicity of 220 mg/m² melphalan (HDM 220) followed by autologous stem cell transplantation in 16 patients with advanced haematological malignancies. Pharmacokinetic parameters (mean values of steady-state volume of distribution 14.6 l/m², total body clearance 313 ml/min/m², elimination half-life 46 min) were the same as those of 140 or 200 mg/m² melphalan in previous reports. HDM 220 was feasible. Extramedullary toxicity was mainly W.H.O. grade 4 mucositis (13/16 patients). The median duration of 41 d (10, not reached) of thrombocytopenia <25 × 10⁹/l was long. In multiple myeloma the response rate was 89% in heavily pretreated patients, suggesting that HDM 220 could be considered earlier in the course of the disease as an alternative consolidation therapy.     

Targeting NF-kappaB in Waldenstrom macroglobulinemia

The nuclear factor-B (NF-B) path-way has been implicated in tumor B-cell survival, growth, and resistance to therapy. Because tumor cells overcome single-agent antitumor activity, we hypothesized that combination of agents that target differentially NF-B pathway will induce significant cytotoxicity. Therapeutic agents that target proteasome and Akt pathways should induce significant activity in B-cell malignancies as both pathways impact NF-B activity. We demonstrated that perifosine and bortezomib both targeted NF-B through its recruitment to the promoter of its target gene IB using chromatin immunoprecipitation assay. This combination led to synergistic cytotoxicity in Waldenstrom macroglobulinemia (WM) cells that was mediated through a combined reduction of the PI3K/Akt and ERK signaling pathways, found to be critical for survival of WM cells. Moreover, a combination of these drugs with the CD20 monoclonal antibody rituximab further increased their cytotoxic activity. Thus, effective WM therapy may require combination regimens targeting the NF-B pathway.      

Role of beta-adrenoreceptor antagonism in the prevention of reperfusion ventricular arrhythmias: effects of acebutolol, atenolol, and d-propranolol on isolated working rat hearts subject to myocardial ischemia and reperfusion

The role of catecholamines in the genesis of ventricular arrhythmias during the reperfusion period following coronary occlusion remains incompletely understood. An isolated rat heart preparation, free from the influence of autonomic innervation or of circulating catecholamines, was used to assess the effects of beta-adrenoceptor blockade. The hearts were prelabeled with tritiated norepinephrine ( NE3H ), and the total radioactivity and that in NE3H were measured in the effluent coronary flow. The left main coronary artery was ligated for 10 minutes after which reperfusion followed. The liberation of NE3H and the development of ventricular tachycardia and fibrillation were monitored throughout. The cardioselective beta-antagonist agent, acebutolol, in a high concentration (1.1 X 10(-4)M), had good beta-antagonist effect in response to the added isoproterenol (10(-6)M); this concentration of acebutolol also suppressed sustained reperfusion ventricular arrhythmias but unexpectedly increased the release of NE3H . Atenolol, another cardioselective agent, did not prevent reperfusion ventricular arrhythmias even in a high concentration of 40 mg/L (1.5 X 10(-4)M). The d-isomer of propranolol, with poorer beta-antagonist properties than the l-isomer, prevented such ventricular arrhythmias in a concentration of 1.3 X 10(-5)M, which was low when compared to that of atenolol. It is proposed that the beta-antagonist activity of the compounds tested could not explain the inhibition of reperfusion ventricular arrhythmias and that another quality such as membrane-stabilizing activity may be involved.     

Regular exercise,hormone replacement therapy and the age-related decline in carotid arterial compliance in healthy women

OBJECTIVE: Carotid arterial compliance is reduced with age in sedentary estrogen-deficient women, contributing to the development of cardiovascular disorders. We determined the effects of regular aerobic exercise, hormone replacement therapy (HRT), and their interaction on carotid arterial compliance using a combination of cross-sectional and intervention study designs. METHODS: Cross-sectionally, we studied three groups of healthy postmenopausal women (50-80 years): 20 sedentary not taking HRT; 24 sedentary taking HRT; and 14 endurance-trained not taking HRT; and 11 sedentary premenopausal controls (20-37 years). In the intervention study, 12 sedentary postmenopausal women (58+/-3 years) who were taking HRT were studied before and after participation in a 3-month aerobic exercise (walking) program. Carotid arterial compliance was measured via simultaneous common carotid artery ultrasound imaging and applanation tonometry. RESULTS: Cross-sectional study. Carotid arterial compliance was lower (P<0.001) in all three postmenopausal groups compared with premenopausal women. Among the postmenopausal groups, arterial compliance was 33-43% higher in the sedentary HRT and endurance-trained women than in their sedentary estrogen-deficient peers. Intervention study. Arterial compliance increased (P<0.05) by approximately 40% to levels that were no longer different than premenopausal women. CONCLUSIONS: HRT use and regular aerobic exercise are associated with augmented carotid arterial compliance in healthy postmenopausal women. Moderate, short-term aerobic exercise can restore carotid arterial compliance in previously sedentary postmenopausal women taking HRT.     

Combination of quinine as a potential reversing agent with mitoxantrone and cytarabine for the treatment of acute leukemias: a randomized multicenter study

A phase III prospective randomized multicenter study was performed to determine whether quinine could improve the response rate of poor-risk acute leukemias (ALs) to standard chemotherapy including a multidrug resistance (MDR)-related cytotoxic agent. The rationale of the study was based on the negative prognostic value of MDR phenotype in ALs and the ability of quinine to reverse this phenotype both in vitro and ex vivo. Three hundred fifteen patients (median age, 49 years; range, 16 to 65) with relapsed (n = 108) or refractory (n = 32) acute myeloblastic leukemia (AML), relapsed (n = 27) or refractory (n = 9) acute lymphoblastic leukemia (ALL), secondary AL (n = 22) or blastic transformation of myelodysplastic syndrome ([MDS] n = 74) or myeloproliferative syndrome ([MPS] n = 43) were randomly assigned to receive mitoxantrone ([MXN] 12 mg/m2/d, days 2 to 5) and cytarabine ([Ara-C] 1 g/m2/12 h, days 1 to 5) alone or in combination with quinine (30 mg/kg/d, days 1 to 5; continuous intravenous infusion beginning 24 hours before MXN infusion). Side effects of quinine were observed in 56 of 161 quinine-treated patients and disappeared in all but four cases after one or two 20% dose decreases. Sera from quinine-treated patients showed increased MXN uptake in an MDR-positive cell line compared with matched sera obtained before quinine infusion. Quinine induced a significant increase in the incidence of nausea, vomiting, mucositis, and cardiac toxicity. A complete response (CR) was observed in 85 of 161 patients (52.8%) from the quinine-treated group versus 70 of 154 patients (45.5%) in the control group (P = .19). The most important differences between quinine and control group CR rates were observed in patients with refractory AMLs and blastic transformation of MDS and MPS. The CR rate was higher in P-glycoprotein-positive cases, although the difference was not significant. Failure of the regimen due to blastic persistence or blast number increase was higher in the control group (61 of 154 patients) than in the quinine group (45 of 161, P = .04). Early death was observed in eight cases (four in each arm) and death in aplasia in 27 cases (20 in quinine group v seven in control group, P = .01). The significant increase of toxicity in the quinine arm could have masked the clinical benefit of MDR reversion in poor- risk ALs.     

Front-line high-dose therapy with autologous stem cell transplantation for high risk Hodgkin's disease: comparison with combined-modality therapy

This retrospective study compares high-dose therapy (HDT) with autologous stem cell transplantation and combined-modality treatment (CT) as a first-line therapy for Hodgkin's disease (HD) for patients with both a clinical stage (CS) IV and/or a mediastinal mass > or =0.45 of the thoracic diameter (MM > or =0.45) at diagnosis, and an incomplete response after the first-line chemotherapy. Data on 42 grafted patients (GP) in Nantes Hospital, France and on 108 combined-modality treated patients (CTP) from two protocols of the GOELAMS group, France (POF 81 and H90) was analyzed. Both groups were comparable except for pulmonary disease in excess in the grafted group (P = 0.01). Among GP, 95% were in complete response at the end of first-line treatment and 77% among CTP. Median follow-up was 53 months (range, 7 to 128 months) for GP and 88 months (range, 25 to 181 months) for CTP. The 5-year freedom from progression (FFP) and event-free survival (EFS) rates were better for GP (87% vs 55% for FFP: P = 0.0004 and 81% vs 51% for EFS: P = 0.0004) whereas the overall survival (OS) rates did not differ significantly (85% for GP vs 71% for CTP: P = 0.06). Similar results were obtained for the groups with a response > or =50% after initial chemotherapy: 91% vs 65% for FFP, P = 0.01; 87% vs 61% for EFS, P = 0.02; and 92% vs 77% for OS, P = 0.2; and for the groups with a response <50%: 80% vs 22% for FFP, P = 0.0003; 72% vs 13% for EFS, P = 0.0001; and 76% vs 46% for OS, P = 0.04. This study shows a better control of the disease with HDT.