GTP-mediated differentiation of the human K562 cell line: transient overexpression of GATA-1 and stabilization of the gamma-globin mRNA.

Induction of specific gene expression may provide an alternative or a support to conventional cytotoxic chemotherapy of cancer, as well as to therapy for sickle cell diseases. In this respect, pharmacological induction of expression of the endogenous gamma-globin gene is a realistic approach to therapy of beta-globin disorders. Erythroid differentiation and inhibition of proliferation of the human CML K562 cell line was induced by guanosine 5'-triphosphate (GTP). The hemoglobin production in cells was correlated to an increase in alpha- and gamma-globin mRNA expression. At the transcriptional level, we showed that both the expression of the major erythroid transcription factor GATA-1 (protein and mRNA) and its binding capacity to the gamma-globin gene promoter was transiently increased. Moreover, GTP moderately stimulated the gamma-globin gene promoter after 48 h of treatment. At the post-transcriptional level, GTP treatment led to a drastic increase of the gamma-globin mRNA half-life. This stabilizing effect of GTP was mediated via the 3'-untranslated region (3'-UTR) of the gamma-globin mRNA. In conclusion, mechanism of GTP-mediated differentiation of K562 cells is linked to an early activation of gamma-globin gene transcription followed by a stabilization of its mRNA.

Regulation of transcription of the glutathione S-transferase P1 gene by methylation of the minimal promoter in human leukemia cells.

To study the relationship between methylation and the transcriptional activity of the minimal promoter of the glutathione S-transferase GSTP1 gene encoding glutathione S-transferase P1-1, GSTP1 mRNA levels as well as basal promoter activity were compared in human leukemia cell lines. The K562 erythroleukemia cell line presented a strong GSTP1 promoter activity, as measured in transient transfection assays using a luciferase reporter plasmid, and correlated with a high mRNA whereas in Raji cells no mRNA was expressed. In order to establish a relationship between the expression and the methylation status, we used in vitro bisulfite sequencing which indicated that both methylated and unmethylated GSTP1 promoter alleles coexisted in K562 cells, whereas Raji lymphoma cells showed a nearly uniform hypermethylation of the promoter region. To determine the impact of methylation, we used in vitro SssI methylation of the minimal GSTP1 promoter, which led to the silencing of the promoter activity in transient transfection assays in expressing K562 as well as in non-expressing Raji cells. These data are in good agreement with previously obtained results and indicate that methylation of CpG sites of the basal promoter is an essential mechanism in the control of GSTP1 gene expression in human leukemia.

Phorbol ester responsiveness of the glutathione S-transferase P1 gene promoter involves an inducible c-jun binding in human K562 leukemia cells.

Overexpression of the glutathione S-transferase P1 (GSTP1) gene is related to drug resistance in human cancer cells. However, the mechanisms of the transcriptional activation of this gene remain unclear. In this study, we examined the molecular mechanisms underlying phorbol ester mediated gene regulation using human K562 leukemia cells as a model. Promoter deletion analyses revealed that the activator protein-1 (AP-1) transcription factor site was crucial for 12-O-tetradecanoyl phorbol 13-acetate (TPA)-mediated GSTP1 gene transcription. Electrophoretic mobility shift assays and transient transfection analysis demonstrated that both DNA binding and transactivation activities of AP-1 were induced by TPA. By supershift analysis, we identified transcription factors c-jun and fra-1 as well as NF-E2p45 as components of the induced binding complex. These results show for the first time that the phorbol ester TPA is involved in the molecular mechanism(s) mediating the activation of the GSTP1 promoter in a human leukemia model.

A double-blind study in hypertensive patients of an original new compound, indapamide.

In a double-bind crossover study in 18 patients with essential hypertension, the hypotensive activity of 5 mg. indapamide daily was compared with 40 mg. frusemide daily over a period of 4 months after an initial 15 days on placebo. The overall clinical assessment showed satisfactory blood pressure control in 72% of patients receiving indapamide compared with 57% on frusemide. The weight of patients on active therapy dropped significantly with both products, but to a greater extent with indapamide. Indapamide was well-tolerated by all 18 patients; 3 patients on frusemide developed side-effects. The results of blood chemistry investigations are discussed. Variations in potassium levels during indapamide therapy were modest and did not warrant the use of potassium supplements.

[Use of digitalis glycosides in severe disorders of intra-ventricular conduction]. / Utilisation des digitaliques en cas de troubles sévères de la conduction intra-ventriculaire.

The use of digitalis in severe disorders of intra-ventricular conduction is debatable, and some consider it contra-indicated. Once it had been shown that the latter attitude is at best based on contraversial theoretical arguments, two types of study were undertaken: 1. Nine patients with bilateral bundle branch block had intracavitary recordings made of the HV interval both before and for one hour after the administration of lanatoside C (0.8 to 1.6 mg). In no case was this interval found to be increased, indicating that there was no increase in the original conduction defect. 2. Thirty four patients with complete right bundle branch block and associated left antero-superior hemiblock were digitalised, and followed up for an average of 16 months; only 2 complete atrio-ventricular blocks occurred (5.9%). The risk of complete atrio-ventribular block occurring within a year (4.5% in our series) does not differ significantly from that in an identical control group of 38 patients with the same conduction defect, but who were not digitalised (6%). Three patients had a therapeutic overdose of digitalis with no observed increase in their atrio-ventricular block. The authors conclude that it is perfectly in order to digitalise a patient with a severe intra-ventricular conduction defect.

[Anatomic aspects of Prinzmetal's angina: apropos of an anatomo-clinical case]. / Les aspects anatomiques de l'Angor de Prinzmétal: à propos dune observation anatomoclinique

Report of one case of Prinzmetal variant of angina pectoris with a typical clinical and electrocardiographic picture in a man aged 87. Severe arrhythmias resulted in death of the patient. On autopsy a moderate narrowing of the anterior interventricular artery was demonstrated. In that relation, a review of the literature on the anatomical lesions and coronary arteriographic data of Prinzmetal angina was performed. It showed that in some cases Prinzmetal angina could be observed while the coronary artery lesions were very moderate. The pathogenesis of these facts was discussed.

[Treatment of obstructive cardiomyopathy using myotomy in a 67-year-old patient. Pharmacological and angiographical studies]. / Traitement d'une cardiomyopathie obstructive par myotomie chez un sujet de 67 ans. Etudes pharmacologique et angiographique

The case is reported of a 67 year old man with obstructive cardiomyopathy treated by an extended myotomy. Serial phonomechanographic tracings and the pre- and post-operative angiograms show the steady progress of the disease towards a major disturbance of left ventricular compliance which became resistant to propranolol, and was partially reversed by myotomy.

[Ascending aortic aneurysm with mucoid infiltration of the media and aortic leaflets. Pathogenic hypotheses- surgical consequences]. / Les anévrysmes de l'aorte ascendante avec infiltration mucoïde de la média et des sigmoïdes. Hypothèses pathogéniques - conséquences chirurgicales.

The theoretical and practical problems posed by aneurysms of the ascending aorta with mucoid infiltration of the Media and the aortic leaflets are discussed with reference to two suggestive cases. These histological changes are not specific for Marfan's syndrome, the relation with which is very inconstant. Incomplete replacement of the affected tissues risks a recurrence which is especially serious when the sinus of Valsalva is involved. Therefore, total replacement of the ascending aorta with aortic valve replacement and reimplantation of the coronary arteries is generally indicated. Histology of the excised tissues should be performed routinely with specific stains for mucopolysaccharides. Close follow-up of operated patients with this condition is recommended, especially those with only partial replacements.

[Anti-arrhythmic effects of injectable amiodarone. Apropos of 100 cases]. / Les effets antiarythmiques de l'amiodarone injectable. A propos de 100 cas

The effects of amiodarone by injection have been studied in 100 patients. 50% of these patients were in cardiac failure. Amiodarone was given intravenously over 30 seconds in a dose of 300 mg; in 15 of the patients a further dose of 150 mg was given after ten minutes. Amiodarone was found to be particularly effective in the tachy-arrhythmias (90% successful) in which it brought about slowing (18 cases out of 30) or conversion (17 cases out of 30). Just as good results were obtained for the atrial tachycardias (90% success rate) and in the junctional tachycardias. This treatment is less effective for atrial flutter (50% successful) and for ventricular arrhyrthmia, in which the success rate was only 60%. It is possible to use the defibrillator after amiodarone has been administered. This drug is well tolerated, and no increase in cardiac failure has been noted in these patients. There does remain, however, the possibility of hypotension and perhaps of circulatory collapse, which is rapidly reversable; this is probably due to vasodilator activity. Intracavitary studies in 8 patients have shown that amiodarone causes slowing of sino-atrial and of atrio-ventricular conduction. Amiodarone may equally worsen a distal conduction defect. The uses for this anti-arrhythmic drug, which is particularly effective at the atrial level, are discussed in this paper.