Hepatocyte growth factor-activated NF-kappaB regulates HIF-1 activity and ODC expression, implicated in survival, differently in different carcinoma cell lines

Hepatocyte growth factor (HGF)-stimulated Met signaling influences tumor survival, growth and progression, all processes involving the transcription factor NF-kappaB. NF-kappaB plays a complex role in the control of survival due to the influence of cellular factors acting downstream. We undertook a comparative investigation of two human breast carcinoma cells with different grades of malignancy and HepG2 hepatoma cells, which present a biphasic response to HGF (proliferation followed by apoptosis). We found evidence that HGF induced gene patterns characteristic of survival rather than apoptosis depending on the cell type. The ability of NF-kappaB to regulate expression of hypoxia-inducible factor-1alpha (HIF-1alpha), a survival/anti-apoptotic gene in cancer, seemed to be critical. In the HepG2 and MCF-7 (low invasive breast carcinoma) cell lines increased transcription and translation were responsible for HIF-1alpha induction after HGF. The regulation by NF-kappaB was mainly at the level of the 5'-UTR of the HIF-1alpha message. HIF-1 (alpha/beta heterodimer) was likely to transactivate Mcl-1, another anti-apoptotic gene. Opposite results were observed in MDA-MB-231 cells (highly invasive breast carcinoma), which have high NF-kappaB activity, further inducible by HGF, because HIF-1alpha mRNA expression and HIF-1 transactivating capacity were HGF-insensitive while the alpha subunit seemed to be degraded after HGF. However, ornithine decarboxylase (ODC) and heme oxygenase mRNA expression persistently increased. By transiently transfecting two ODC gene reporters we demonstrated that ODC is a target gene of NF-kappaB in HGF-treated tumor cells. By regulating HIF-1 activity and specific gene expression downstream, NF-kappaB may influence the survival threshold, with an impact on the fate of carcinoma cells after prolonged HGF treatment.

[Comparison of amiodarone and quinidine in the conversion to sinusal rhythm of atrial fibrillation of recent onset]

The effectiveness of amiodarone and quinidine in converting atrial fibrillation of recent onset (less than three weeks) to sinus rhythm was compared in a randomized, open-label study. Patients with signs of heart failure determining a NYHA class 3 or 4, acute myocardial infarction, unstable angina pectoris, sick sinus syndrome, Wolff-Parkinson-White syndrome, conduction disturbances, dysthyroidism, or undergoing concomitant therapy with antiarrhythmic drugs, were excluded from the study. Sixty-eight consecutive patients were randomized to receive amiodarone (group A) or quinidine (group B). Group A was treated with amiodarone intravenously as a bolus of 5 mg/Kg over a 20 min period followed by a 15 mg/Kg infusion during the first 24 hours and then orally at a dose of 0.4 g every 6 hours. Group B was treated with quinidine sulphate orally at a dose of 0.2 g every 6 hours during the first day; 0.4 g every 6 hours the second day and 0.6 g every 6 hours during the third day of therapy. Quinidine was preceded by rapid intravenous digitalization depending on the patient's clinical status so as to obtain a ventricular rate of about 100 beats/min, with subsequent oral digitalis administration in maintenance doses. Both treatments were continued until conversion or for a maximum of three days. If the sinus rhythm was not restored, patients underwent electrical cardioversion. Drug efficacy was assessed on the basis of conversion to sinus rhythm. Six patients converted to sinus rhythm with intravenous digitalization alone and were excluded from the comparison between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic effects of transdermal nitroglycerin in stable angina pectoris: a within-patient, placebo-controlled study

The efficacy of transdermal nitroglycerin patches, releasing 20 mg of active substance over a period of 24 h (TDN 20), was investigated in 10 patients with stable exercise-induced angina pectoris. The study was divided into 3 periods: the first part was an acute, within-patient, crossover, double-blind, placebo-controlled study, in which patients performed a cycloergometric exercise test 4 and 24 h after the application of the patches (TDN 20 or placebo). During the 2nd period, patients were given TDN 20, in single blind conditions, for 4 weeks and another exercise test was performed, on the last day, 4 and 24 h after patch application. Finally, after a one-day placebo wash-out, a second acute study similar to the first was performed. Four h after dosing, exercise duration to 1 mm ST segment depression was 441 s and 314 s (p less than 0.01) for TDN 20 and placebo, respectively (first acute study), 394 s for TDN 20 after chronic treatment (p less than 0.001 vs acute placebo) and 472 and 354 s (p less than 0.001) for TDN 20 and placebo, respectively (second acute study). No difference in exercise duration to 1 mm ST segment depression was found between TDN 20 and placebo, 24 h after administration, in any of the periods. Blood pressure significantly decreased and heart rate significantly increased 4 h after TDN dosing (in comparison with placebo) in both the acute studies, but no difference was observed after chronic TDN treatment. In conclusion, TDN 20 increases exercise tolerance 4 h after the application of both acute and chronic treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

[Prognostic meaning of the echo-dipyridamole test in recent non-Q myocardial infarct]

The aim of this study was to evaluate the usefulness of the dipyridamole-echocardiography test soon after non Q wave myocardial infarction. Forty-two consecutive patients admitted to the Coronary Care Unit for a first episode of a non Q wave myocardial infarction were enrolled. Dipyridamole-echocardiography test and exercise stress test were performed on 29/42 patients without clinical or electrocardiographic evidence of residual ischaemia, before hospital discharge (from 7 to 15 days after admission). They were followed-up for 1 to 15 months (mean 11.9) or until one of the following clinical end points occurred: recurrence of myocardial infarction, angina or cardiac death. Over a period of 4 minutes, 0.56 mg/kg of dipyridamole was infused intravenously. The test was considered positive when a new transient wall motion abnormality was confirmed by two independent observers. According to these criteria a positive test was observed in 7/29 patients (24%) and a negative one in 22/29 (76%). The exercise stress test was positive in 12/27 patients (44%). Subsequent coronary events occurred in all the patients (100%) with positive dipyridamole-echocardiography test and in 7/22 patients (32%) with negative dipyridamole-echocardiography test (p less than 0.001). Five out of the 7 patients with positive test who underwent coronary angiography showed multivessel coronary artery disease. The sensitivity, specificity and positive predictive value of dipyridamole-echocardiography test for the identification of patients at risk for subsequent coronary events were respectively 50%, 100%, 100%, while for exercise stress test these values were 83%, 86% and 75%.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of a transdermal patch system containing nitroglycerin on exercise tolerance in patients with angina pectoris. Double-blind, placebo controlled, comparison with slow-release nifedipine and verapamil

The antianginal efficacy of nitroglycerin (NTG), given in a new transdermal therapeutic system (TTS), was compared with that of nifedipine and verapamil, both in slow-release (SR) formulation, in a randomized, double-blind, placebo-controlled study, carried out in 8 patients with stable exercise-induced angina pectoris. TTS NTG 40 cm2 (releasing 20 mg of NTG over 24 hours), nifedipine 20 mg SR, verapamil 120 mg SR and placebo were given once on 4 consecutive days according to a 4 X 4 latin-square design, twice replicated. A cycloergometric symptom-limited exercise test was performed 4 and 8 hours after the administration of each drug. Four hours post-dosing, mean exercise duration was 407 sec. after placebo and 523 (+28%) and 485 (+ 19%) sec. after TTS NTG and nifedipine SR respectively, while at the 8th hour it was 375 sec. after placebo, and 515 (+ 37%) and 457 (+ 21%) sec. after TTS NTG and nifedipine SR. Exercise duration after verapamil was similar to that after placebo. In comparison with placebo maximal workload and total work performed were significantly higher on TTS NTG and on nifedipine at both times of observation, but no significant differences were seen after verapamil. Peak exercise systolic blood pressure was nearly identical after all the treatments tested. Peak exercise heart rate and pressure rate product were both significantly higher on TTS NTG, as well as on nifedipine, in comparison with placebo, while values after verapamil did not differ from those after placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

[Drug therapy combinations in angina pectoris]

The critical level of myocardial oxygen consumption at which anginal pain will occur can be assessed in patients with coronary artery disease. We studied the results of exercise ECG in patients with effort angina, administered placebo, nitrate derivatives, betablockers, and calcium inhibitors, alone and in different associations. Nitrate derivatives and calcium inhibitors appeared to be more effective than betablockers. The study demonstrated the utility of the association of betablockers with other drugs with a more effective anti-anginal action but without the hypotensive or antiarrhythmic effects of betablockers which are often very desirable in the treatment of coronary artery disease.

Role of the kidney in 'salt and water dependent hypertension' of end-stage disease

1. Blood pressure, plasma renin concentration, exchangeable body sodium, plasma volume and extracellular fluid volume were measured in five patients on maintenance haemodialysis for end-stage renal disease in whom hypertension was relatively easy to control by the combination of dialysis and restriction of salt intake. Measurements were made on three occasions: on a free salt intake the day before dialysis; on a low salt intake the day after dialysis; on a free salt intake the day before dialysis after nephrectomy.

2. The fall of blood pressure after haemodialysis and salt intake restriction was accompanied by a decrease of exchangeable body sodium and body fluids while plasma renin concentration increased. The fall of blood pressure after bilateral nephrectomy was accompanied by a fourfold decrease of plasma renin without any change of the other variables.

3. The hypertension of these patients might thus be considered ‘salt and water dependent’ or ‘renin dependent’ according to the means used to decrease blood pressure.