The cytotoxicity and mode of action of 2,3,4-trisubstituted pyrroles and related derivatives in human Tmolt4 leukemia cells

4-Carbethoxy-1-methyl-2-phenacyl-3-phenylpyrrole (9), 4-carbethoxy-2-(4-methoxybenzoyl)-3-(4-methoxyphenyl)pyrrole (10) and 2-(4-methoxybenzoyl)-3,4-bis-(4-methoxyphenyl)pyrrole (11) proved to be potent cytotoxic agents against the growth of murine and human leukemias and lymphomas. Selective toxicity was demonstrated against the growth of solid tumors, e.g., human adenocarcinoma of the colon SW480 and ileum HCT-8, glioma U-87-MG, and rat UMR-106 osteosarcoma. A mode of action study in Tmolt4 leukemia cells demonstrated that the agents inhibited de novo purine synthesis at the regulatory sites PRPP-amido transferase, IMP dehydrogenase as well as dihydrofolate reductase resulting in significant inhibition of DNA synthesis in 60 min. Other biochemical sites which were affected significantly were thymidylate synthetase, DNA polymerase alpha, RNA polymerases, nucleoside kinase and ribonucleoside reductase.

Synthesis and characterization of deoxyguanosine-benzoquinone adducts

Benzene expresses its carcinogenic potential in humans largely in the form of acute leukemia. Because an understanding of the formation of DNA adducts by benzene metabolites may help to explain the etiological role they play in benzene-induced bone marrow disease, we have synthesized, isolated and characterized adducts formed by the reaction of deoxyguanosine with hydroquinone and p-benzoquinone, two toxic metabolites of benzene. [3H]Deoxyguanosine and [14C]hydroquinone reacted in neutral aqueous buffer containing iron to form two dual-labeled products, which were separated using HPLC. When p-benzoquinone was substituted for hydroquinone, the same adducts were formed in the absence of added iron. The ultraviolet and fluorescence spectra of the less polar adduct, called Adduct 2, were distinctly different from the spectra of the starting materials. NMR and mass spectrometry suggested a compound with a mass of 357 with the p-benzoquinone moiety bound to the N-1 and N2 positions of deoxyguanosine. Based on these data it is proposed that Adduct 2 is (3'OH)benzetheno(1,N2)deoxyguanosine. The more polar product, Adduct 1, was found to have a unique ultraviolet spectrum but did not appear to be fluorescent. Both adducts were observed after calf thymus DNA was incubated with hydroquinone and digested to its constituent nucleosides.

Enzyme immunoassay using a novel recombinant polypeptide to detect human immunodeficiency virus env antibody

A unique antigen, CBre3, has been synthesized from a genetically engineered clone to detect human immunodeficiency virus (HIV) env antibodies with high sensitivity and specificity. The antigen contains sequences derived from both envelope proteins of HIV, i.e., gp120 and gp41, and was purified free of Escherichia coli proteins detectable by Coomassie stain or immunoblotting with E. coli antiserum. The purified recombinant polypeptides were used as antigen in an enzyme immunoassay (EIA) to screen serum samples from healthy and HIV-infected individuals. The same samples were also tested by radioimmunoprecipitation (RIP) for gp120 and gp160 HIV antibodies. All samples containing gp120 and gp160 antibodies by RIP had CBre3 EIA values greater than 0.35 (n, 122; range, 0.37 to 2.1+; median, 1.65). All RIP HIV antibody-negative samples had CBre3 EIA values less than 0.25 (n, 140; mean, 0.052; standard deviation, 0.045; range, 0.00 to 0.22). The endpoint titer of a standard positive control serum was 1:10,000 by RIP and by CBre3 EIA. The assay was 100% accurate in three proficiency panels. It easily detected six samples from individuals whose infections were confirmed by culture; these samples were reactive only with p24 by Western blot. The samples also were positive for gp120 and gp160 antibodies by RIP. These data suggest that the CBre3 EIA can detect env antibodies as sensitively and specifically as RIP and with more sensitivity than Western blot.

Epstein-Barr virus infection in renal transplant recipients. Effects of antithymocyte globulin and interferon

We studied Epstein-Barr (EB) virus excretion and antibody in 41 renal transplant recipients enrolled in a placebo-controlled trial of human leukocyte interferon. Half the patients were also treated with antithymocyte globulin. Epstein-Barr virus excretion occurred more often in recipients of cadaver kidneys (P = 0.03) and those receiving antithymocyte globulin (P = 0.04) and less often in patients given interferon (P = 0.08). Antibody to viral capsid antigen increased fourfold or more in 12 of 22 patients treated with antithymocyte globulin and in none of the non-antithymocyte globulin-treated group (P = 0.0002). Antibody to the restricted component of early antigen rose fourfold or more in eight patients and appeared related to the occurrence of syndromes similar to those attributed to cytomegalovirus in transplant recipients. We conclude that increasing immunosuppression augments the rate of EB virus reactivation and that EB virus may be an important pathogen in heretofore ill-defined syndromes.

Controlled clinical trial of prophylactic human-leukocyte interferon in renal transplantation. Effects on cytomegalovirus and herpes simplex virus infections

A double-blind, placebo-controlled trial of interferon prophylaxis against viral infections was conducted in renal-transplant recipients receiving standard immunosuprressive therapy with or without antithymocyte globulin. Interferon was administered for six weeks, beginning on the day of transplantation. Cytomegalovirus excretion began earlier and viremia was more frequent in placebo-treated than in interferon-treated patients. Cytomegalovirus viremia correlated with clinical syndromes was more frequent in recipients of antithymocyte globulin. In contrast, neither interferon nor antithymocyte globulin altered excretion of herpes simplex virus. Reversible leukopenia and thrombocytopenia occurred in seven interferon recipients. Patient and graft survival were comparable in interferon and placebo groups. There preliminary results suggest that a six-week course of prophylactic interferon delays shedding of cytomegalovirus and decreases the incidence of viremia after transplantation. In contrast, antithymocyte globulin appears to increase the severity of infection from cytomegalovirus among these patients.

[Twenty-five years' experience in epidemiology and prophylaxis of epidemics at the Centre for Salmonella of Hamburg (author's transl)]

Salmonella-epidemiology has changed fundamentally since underdeveloped countries have entered international trade and export food-supplies which, due to less stringent controls, are already contaminated either in the countries of origin or in transit. This is shown by numerous case histories of food-poisoning. Multifarious causes of infection from imported food-stuffs are exposed and also the epidemiological consequences from latently infected fat-stock and poultry. Prophylactic measures and advice on preventive treatment are given. The progressive automation in many factories and plants, with aspirations to the highes-degree of efficiency, frequently hides potential sources of infection with a shining facade of chrome and plastic. In the planning and servicing of technical installations, which later may well prove to be a source of infection, sanitary experts are rarely consulted, or if so too late. This paper also emphasises the considerable influence of mass-tourism with the consequent introduction of exotic Salmonella serotypes, and also the potential danger of faeca contamination on motorway rest-stops.