The N1-acetylderivatives (ASA) of sulphanylamides (SA) were prepared and their stability to hydrolysis was evaluated together with the spectroscopic and antibacteric activity parameters, with the aim ...both of obtaining electronic structure-activity relationships and of comparing these results with those previously found for SA. From our results it appears that: a) the stability to hydrolysis is dramatically reduced on passing from the aqueous medium (pH 7) to the culture broth, and that b) in general, the ASA examined do not show any greater antibacterial activity with respect to the parent compounds, as suggested by the values of the spectroscopic indices-taken as experimental electronic indices. This result is in full agreement with the structure-activity relationships previously proposed fo the sulpha drugs.
Molecules formed by two pharmacophoric synthons--4-H2N--C6H4--SO2NH--and 2,4-diaminopyrimidine--were prepared. These structural units, with sulphamidic and antifolic action respectively, are bound ...without mutual electronic interaction, as demonstrated by their experimental electronic indices. The compounds were tested for activity on several bacterial strains and their biological activity was compared with that of molecular combinations formed by 4-aminobenzensulphonamide and substituted 2,4-diaminopyrimidines, to discover whether these two pharmacophoric synthons, so bound, are synergic.
The alkaline deacylation rate constants of a collection of N4-acetylderivatives of acidic and non-acidic sulphonamides (SA) clearly show a definite trend due to the intramolecular effects induced by ...the different substitutions on the N1 nitrogen. The rate constant is interpreted as a reactivity index of the corresponding non-acetylated compound, and is found to be strictly correlated with the electron-availability of the p-amino group; thus providing an interesting correlation with the antibacterial activity of these drugs. Moreover, the reported experiments corroborate early predictions that the greatest reactivity of the p-amino group pertains to p-aminobenzoate (PAB) in the series of chemically related compounds, and that SA anions show the highest chemical and electronic resemblance to the essential metabolite (PAB); thus the high antibacterial activity of SA anions correctly corresponds to its close resemblance to the metabolite.
In this work, a method based on information theory is developed to make predictions from a sample of nonlinear time series data. Numerical examples are given to illustrate the effectiveness of the ...proposed method.
•Economic, chaotic time-series are analyzed with information theory methods.•The maximum entropy principle is appealed to.•Predictions concerning the Dow-Jones series are made.
Renal involvement during graft-versus-host disease following haematopoietic cell transplantation for multiple myeloma has never been described. We report a case of a recipient who developed nephrotic ...syndrome and membranous glomerulonephritis 22 months after the graft and 6 months after cyclosporine withdrawal. Symptoms resolved when immunosuppressive therapy was reinstituted.
