Repeated cycles of Clostridium-directed enzyme prodrug therapy result in sustained antitumour effects in vivo

The unique properties of the tumour microenvironment can be exploited by using recombinant anaerobic clostridial spores as highly selective gene delivery vectors. Although several recombinant Clostridium species have been generated during the past decade, their efficacy has been limited. Our goal was to substantially improve the prospects of clostridia as a gene delivery vector. Therefore, we have assessed a series of nitroreductase (NTR) enzymes for their capacity to convert the innocuous CB1954 prodrug to its toxic derivative. Among the enzymes tested, one showed superior prodrug turnover characteristics. In addition, we established an efficient gene transfer procedure, based on conjugation, which allows for the first time genetic engineering of Clostridium strains with superior tumour colonisation properties with high success rates. This conjugation procedure was subsequently used to create a recombinant C. sporogenes overexpressing the isolated NTR enzyme. Finally, analogous to a clinical setting situation, we have tested the effect of multiple consecutive treatment cycles, with antibiotic bacterial clearance between cycles. Importantly, this regimen demonstrated that intravenously administered spores of NTR-recombinant C. sporogenes produced significant antitumour efficacy when combined with prodrug administration

Effect of different intravenous iron preparations on lymphocyte intracellular reactive oxygen species generation and subpopulation survival

<p>Abstract</p> <p>Background</p> <p>Infections in hemodialysis (HD) patients lead to high morbidity and mortality rates and are associated with early cardiovascular mortality, possibly related to chronic inflammation. Intravenous (IV) iron is widely administered to HD patients and has been associated with increased oxidative stress and dysfunctional cellular immunity. The purpose of this study was to examine the effect of three commercially available IV iron preparations on intracellular reactive oxygen species generation and lymphocyte subpopulation survival.</p> <p>Methods</p> <p>Peripheral blood mononuclear cells (PBMC) were isolated from healthy donor buffy coat. PBMC were cultured and incubated with 100 μg/mL of sodium ferric gluconate (SFG), iron sucrose (IS) or iron dextran (ID) for 24 hours. Cells were then probed for reactive oxygen species (ROS) with dichlorofluorescein-diacetate. In separate studies, isolated PBMCs were incubated with the 25, 50 or 100 μg/mL iron concentrations for 72 hours and then stained with fluorescein conjugated monoclonal antibodies for lymphocyte subpopulation identification. Untreated PBMCs at 24 hours and 72 hours served as controls for each experiment.</p> <p>Results</p> <p>All three IV iron preparations induced time dependent increases in intracellular ROS with SFG and IS having a greater maximal effect than ID. The CD4+ lymphocytes were most affected by IV iron exposure, with statistically significant reduction in survival after incubation with all three doses (10, 25 and 100 μg/mL) of SFG, IS and ID.</p> <p>Conclusion</p> <p>These data indicate IV iron products induce differential deleterious effects on CD4+ and CD16+ human lymphocytes cell populations that may be mediated by intracellular reactive oxygen species generation. Further studies are warranted to determine the potential clinical relevance of these findings.</p

Interaction of inflammatory cytokines and erythropoeitin in iron metabolism and erythropoiesis in anaemia of chronic disease

In chronic inflammatory conditions increased endogenous release of specific cytokines (TNFα, IL-1, IL-6, IFNγ and others) is presumed. It has been shown that those of monocyte lineage play a key role in cytokine expression and synthesis. This may be associated with changes in iron metabolism and impaired erythropoiesis and may lead to development of anaemia in patients with rheumatoid arthritis. Firstly, increased synthesis of acute phase proteins, like ferritin, during chronic inflammation is proposed as the way by which the toxic effect of iron and thereby the synthesis of free oxy-radicals causing the damage on the affected joints, may be reduced. This is associated with a shift of iron towards the mononuclear phagocyte system which may participate in the development of anaemia of chronic disease. Secondly, an inhibitory action of inflammatory cytokines (TNFα, IL-1), on proliferation and differentiation of erythroid progenitors as well as on synthesis of erythropoietin has been shown, thereby also contributing to anaemia. Finally, chronic inflammation causes multiple, complex disturbances in the delicate physiologic equilibrium of interaction between cytokines and cells (erythroid progenitors, cells of mononuclear phagocyte system and erythropoietin producing cells) leading to development of anaemia of chronic disease (Fig. 1)

Aspects epidemiologiques, cliniques et pronostiques de l’accouchement des adolescentes a Lome en 2010

Objectifs: Décrire les aspects épidémiologiques, cliniques de l’accouchement chez les adolescentes à Lomé. Analyser le pronostic maternel et néonatal immédiat.Patientes et méthodes: Etude rétrospective descriptive et analytique sur une période de 12 mois (janvier à décembre 2010) portant sur 387 dossiers d’accouchement d’adolescentes réalisés dans les quatre maternités de référence de Lomé. Les données ont été traitées à l’aide du logiciel Epi-Info 3.5.1Résultats: La fréquence des accouchements chez les adolescentes était de 3,66 %. L’âge moyen des adolescentes était de 17ans. Dans 71,6 %, l’accouchement a été effectué par voie basse contre 28,4% d’accouchements par césarienne. Les principales indications des césariennes d’urgence étaient la dystocie mécanique, la souffrance foetale et l’éclampsie. La mortalité périnatale était de 90,43‰ et le taux mortalité maternelle liée à l’accouchement des adolescentes était de 127,73 pour 100 000 naissances vivantes.Conclusion: L’accouchement chez les adolescentes semble comporter plus de risques néonatals que maternels. Il faut subventionner les soins obstétricaux chez cette tranche d’âge et améliorer le plateau technique en matière d’accueil des nouveau-nés de petits poids.Mots clés: Accouchement adolescentes, pronostic, LoméEnglish AbstractObjectives: Describing epidemiological and clinical aspects of teenage’ childbirth in Lomé. To analyze immediate maternal and neonatal prognosis. Patients and methods: Retrospective descriptive and analytic study, over a period of 12 months (January-December 2010) on 387 records of teenage’ deliver in the four reference maternities of Lomé. The data were processed using Epi-Info 3.5.1Results: Frequency of teenage’ childbirths was 3.66%. The average age of mothers was 17 years old. In 71.6%, the delivery was performed vaginally against 28.4% cesarean section. Main indications of caesarean section in emergency were obstructed labor, fetal distress and eclampsia. Perinatal mortality rate was 90.43 ‰ and the mortality rate related to maternal childbirth adolescents was 127.73 per 100 000 live births.Conclusion: Teenage’ childbirth seems more risky for neonatal outcome than maternal one. There is a need to totally subsidize obstetrics’ care in this age group and to improve technical platform in small weight newborns management.Keywords: Teen delivery, prognosis, Lom

Combined adenovirus-mediated nitroreductase gene delivery and CB1954 treatment: A well-tolerated therapy for established solid tumors

Gene-directed enzyme prodrug therapy (GDEPT) is a refinement of cancer chemotherapy that generates a potent cell-killing drug specifically in tumor cells by enzymatic activation of an inert prodrug. We describe in vivo studies that evaluate the efficacy and safety of intratumoral (i.t.) injection of an adenovirus vector (CTL102) expressing Escherichia coli nitroreductase (NTR) combined with systemic prodrug (CB1954) treatment. A single i.t. injection of CTL102 (7.5 times 109 to -2 times 1010 particles) followed by CB1954 treatment produced clear anti-tumor effects in subcutaneous (s.c.) xenograft models of four cancers that are likely candidates for GDEPT (i.e., primary liver, head and neck, colorectal and prostate). Virus dose–response studies (s.c. liver model) revealed a steep increase and subsequent rapid plateauing of both NTR gene delivery and anti-tumor efficacy. Evidence of minor virus spread (toxicity) was observed in a s.c. head and neck xenograft model. This was eliminated by passive immunization with neutralizing anti-Ad5 antibodies prior to virus injection without reducing the magnitude of the anti-tumor effect. Preexisting anti-Ad5 neutralizing antibodies may therefore be an advantage rather than an issue in the clinical use of this new therapy