Histochemical study of reverse reactions in experimental leprosy in armadillos

Morphological and histochemical characteristics of reverse reactions in M. leprae-infected armadillos are reviewed. The reverse reactions develop in generalized lepromatous disease and are characterized by a dramatic decrease in mycobacterial macrophage load and the appearance of lymphocytes, epithelioid and giant multinuclear cells with peripheral nucleus distribution. Histochemical investigation has shown a decrease in the activity of redox enzymes and alpha-naphthyl acetate esterase and an increase in beta-glucuronidase activity. The reverse reactions in the liver are accompanied by hepatic granuloma and hepatocyte destruction.     

Isolation of Bacteriophage for Caryophanon latum

Bacteriophage which produce either clear or turbid center plaques have been isolated for native isolates of Caryophanon latum.     

Immunity to Epstein-Barr virus in Hodgkin's disease preceded by infectious mononucleosis

A patient who developed Hodgkin''s disease four years after infectious mononucleosis had elevated serum antibody titres to Epstein-Barr virus and delayed hypersensitivity reactions to membrane antigens prepared from fresh autologous spleen, from spleen cells of another Hodgkin''s patient, and from cell lines known to carry the Epstein-Barr virus genome. Additional studies in more lymphoma patients will be needed to determine the significance of the reactivity against tumour and virus-associated antigens which has been documented in this patient.     

Thermodynamic cycle-perturbation study of the binding of trifluoroacetyl dipeptide anilide inhibitors with porcine pancreatic elastase

The variety of results of crystallographic studies of the serine proteases complexed with isocoumarin inhibitors presents a challenging problem to modeling methods and molecular energetics. Therefore, the thermodynamic cycle-perturbation technique has been used to study a model system of elastase and two peptidic inhibitors. Using the program AMBER, the technique correctly predicts changes of the binding constants for the trifluoroacetyl dipeptide inhibitors in comparison with available experimental (kinetic and crystallographic) data. However, the absolute values obtained are shown to be sensitive to the specific electrostatic interaction potential parameters used in the simulations. The reader and user are cautioned that thermodynamic cycle-perturbation results may be too optimistic by underestimating the accuracy of free energy values. This is especially a matter of concern for those cases where a direct comparison with experimental values is not possible, viz., (1) the stimulation of binding of novel compounds, (2) structurally uncertain binding sites, or (3) structurally different binding modes. With our best 4-31G* ESP (electrostatic potential) charges we were able to reproduce experimentally determined free energy differences (delta delta A) with an accuracy of about 1.5 kcal/mol. Dynamically induced structural changes in the binding site of elastase, and particularly changes in hydrogen-bond patterns of the binding site, are also reported.