Computational investigation of pyrazinamide drugs and its transition metal complexes using a DFT approach

Pyrazinamide, an antituberculosis but documented toxic drug, is subjected to computational investigation along with the metal complexes via a DFT approach to predict the structure-activity and structure-toxicity relationship. 6-31G(d,p) basis set was used for Zn, Ni, Mn, Fe, and Co, while the SDD basis set was applied to Cu, Cr, Cd, and Hg. Several reactivity parameters and charge distribution were calculated and the reactivity profile was estimated. The complexes were found to be soft and polarizable which could be responsible for their binding with bacterial targets to inhibit their growth. In contrast, pyrazinamide which is found to be hard among all is susceptible to being toxic. Moreover, the electronegative nature of the complexes can endow them with a better antibacterial effect. Since metal complexes have been found to be less toxic and more biologically interactive by computational methods, they can be employed as potent drugs for the cure of tuberculosis.

High concordance between marker profiles of 22 human leukemia-lymphoma cell lines tested with the same monoclonal antibodies before and during the second international workshop on human differentiation antigens

Our laboratory participated in the Second International Workshop and Conference on Human Leucocyte Differentiation Antigens. In this international study the reactivity profiles of monoclonal antibodies were analyzed on normal and malignant hematopoietic cells. The Workshop was divided into three categories: the T-cell, B-cell and myelomonocytic cell studies. We blindly tested 159 coded monoclonal antibodies of the panel for the T-cell study on 22 permanently established leukemia cell lines. The monoclonal antibodies were provided by the Workshop Committee and their reactivity with the target cells was visualized by standardized indirect immunofluorescence. After decoding it was recognized that 11 monoclonal antibodies had been examined on these cell lines prior to the Workshop. The reactivity of these 11 monoclonal antibodies was analyzed and compared with the earlier results. From a total of 217 paired tests done blindly in the Workshop study and prior to the Workshop, 191 tests (88%) did not show significantly different data. The possible reasons for discrepancies include nonspecific Fc-receptor-binding on some cell lines and a relatively nonspecific reactivity of some monoclonal antibodies. This analysis demonstrates the stability of the antigen expression on human leukemia-lymphoma cell lines grown at consistently optimal conditions, for the tests, using the same monoclonal antibodies as in the Workshop, had been performed 0.5-5 years prior to the Workshop study. On the other hand, nonspecific Fc-binding, wide "specificity" of monoclonal antibodies and a shift in antigen expression of the cells (due to poor growth conditions, involuntary induction of differentiation and other factors) must be taken into consideration upon immunological analysis.