An aminoacridine derivative for radionuclide therapy: DNA binding properties studied in a novel cell-free in vitro assay

Radiolabelled DNA-binding compounds can be used to increase the efficiency of radionuclide cancer therapy of disseminated disease. In this work, the aminoacridine compound N-[3-(acridine-9-ylamino)-propyl]-3-iodobenzamide (A3) labelled with the Auger-emitting nuclide 125I using Chloramine-T was studied. Optimal labelling conditions of 125I-A3 were investigated and the interaction with DNA was studied using a novel cell-free in vitro assay with naked human genomic DNA in agarose plugs. This novel assay showed to be simple and reliable. The results verify that 125I-A3 specifically binds DNA with low dissociation and is potent in causing double-strand breaks, yielding 1.0-1.4 breaks per decay. In conclusion, 125I-A3 is a most suitable DNA-binding compound for future therapeutic studies of Auger-electron emitters like 125I.     

Effect of recombinant murine granulocyte colony-stimulating factor with or without fluoroquinolone therapy on mixed-infection abscesses in mice

The aim of the study was to determine if immunomodulation of host defense with recombinant murine granulocyte colony-stimulating factor (G-CSF) improves the efficacy of trovafloxacin or moxifloxacin in abscesses containing Bacillus fragilis ATCC 23745 and different Escherichia coli strains varying in virulence. Treatment of mice inoculated with 10(7) CFU B. fragilis and 10(5) CFU low-virulence E. coli with either trovafloxacin (150 mg/kg/day every 24 hours, days 3 to 7) or moxifloxacin (96 mg/kg/day every 12 hours, days 3 to 7), significantly reduced the number of B. fragilis to 6.9 +/- 0.35 and 5.8 +/- 0.10 and that of E. coli to 4.9 +/- 0.09 and 4.2 +/- 0.07 log CFU/abscess for trovafloxacin and moxifloxacin, respectively, compared to controls (B. fragilis 8.7 and E. coli 7.4 log CFU/abscess) on day 8. Also, moxifloxacin was more potent than trovafloxacin. Addition of G-CSF prophylaxis (1 mug once on day -1) or therapy (1 mug/day on days 3 to 7) to fluoroquinolone treatment did not improve the efficacy of fluoroquinolone therapy alone. The effect of moxifloxacin with or without G-CSF prophylaxis on abscesses with a virulent hemolytic E. coli strain was also studied. In moxifloxacin-treated mice, 75% survived infection compared to 10% of controls. Combining moxifloxacin with G-CSF prophylaxis significantly decreased survival (30%) compared to moxifloxacin alone. In addition, G-CSF prophylaxis resulted in a threefold (E. coli) to 100-fold (B. fragilis) increased outgrowth in the abscesses of surviving mice. In conclusion, the addition of G-CSF to a fluoroquinolone is not advisable since, depending on the virulence of the E. coli strains, this might detrimentally influence the outcome of therapy.     

National guidelines for the use of antibiotics in hospitalised adult patients: the SWAB guidelines revisited

Since 1996, the Dutch Working Party on Antibiotic Policy (Stichting Werkgroep AntibioticaBeleid, SWAB) has been developing national guidelines for the use of antibiotics in hospitalised adult patients. As a result of both an inventory of the wishes of the users of these guidelines and the recently developed criteria for evidence-based guideline development, we have revised our format for the development of SWAB guidelines. By involving the members of the relevant professional societies and giving them the opportunity to comment on the guidelines at an early stage, we are aiming for a successful implementation of the guidelines in the hospitals.     

Proinflammatory Cytokines in the Treatment of Bacterial and Fungal Infections

Mortality due to severe bacterial infections has not been markedly effected by the introduction of new antimicrobial drugs over the last 30-40 years. This has emphasized the need for development of new therapeutic strategies to combat sepsis. The outcome of an infection depends on two factors: the growth of the microorganisms (including the effect of antibacterial drugs), and the host's defensive response to the invading organism. It is known that injection of bacterial products into experimental animals leads to enhanced nonspecific resistance to a variety of microorganisms. The discovery of the specific mediators responsible for modulation of host defense has created new possibilities for the development of alternative treatment strategies. Molecules such as interleukins, interferons, tumor necrosis factors and hematopoietic growth factors have become available in recombinant form, and their therapeutic potential in various infectious diseases has been tested in various experimental models of infections. Initial data in various patient groups indicate that adjunctive therapy with recombinant proinflammatory cytokines may have beneficial effects in the treatment of bacterial and fungal infections.     

CD40/CD40 ligand interactions in the host defense against disseminated Candida albicans infection: the role of macrophage-derived nitric oxide

CD40L interaction with CD40 is required for normal cellular immune responses such as T cell-mediated activation of monocytes/macrophages, proinflammatory cytokine production, and leukocyte extravasation. We investigated the role of CD40/CD40 ligand (L) interactions during disseminated candidiasis in CD40L knockout (CD40L-/-) mice. While early during infection there were no differences in the Candida albicans outgrowth in the organs of wild-type and knockout mice, the CD40L-/- mice had a significantly increased yeast load in the kidneys compared to CD40L+/+ mice late during infection. Similar effects were observed in CD40L+/+ mice in which CD40 ligation was blocked by a neutralizing anti-CD40 antibody. The peak TNF-alpha plasma concentrations were significantly lower in the CD40L-/- mice than in CD40L+/+ mice. C. albicans-stimulated production of nitric oxide (NO) by peritoneal macrophages from CD40L-/- in vitro was significantly lower than that of control mice, and this was responsible for a reduced candidacidal activity of CD40L-/- macrophages. The role of endogenous NO synthesis induced by CD40 ligation for the defense against disseminated candidiasis was further demonstrated by the absence of these effects in knockout mice deficient in inducible NO-synthase. In conclusion, absence of CD40/CD40L interactions results in increased susceptibility to disseminated infection with C. albicans through decreased NO-dependent killing of Candida by macrophages.