Use of horseradish peroxidase for gene-directed enzyme prodrug therapy with paracetamol

Gene therapy is a potential method of treating cancer with a greater degree of targeting than conventional therapies. In addition, therapy can be directed towards cells within the tumour population that are traditionally resistant to current treatment schedules. Horseradish peroxidase (HRP) can oxidise paracetamol to N-acetyl-p-benzoquinoneimine via a one-electron pathway. Incubation of human cells expressing HRP with 0.5–10 mm paracetamol reduced clonogenic survival, but had little effect on control cells. A small increase in apoptosis was seen and a decrease in the number of cells undergoing mitosis, consistent with reports in hepatocytes using higher paracetamol concentrations. The cytotoxicity was also seen under conditions of severe hypoxia (catalyst induced anoxia), indicating that the HRP/paracetamol combination may be suitable for hypoxia-targeted gene therapy

A Qualitative Methodology for Studying Parent–Child Argumentation

This chapter provides a detailed exposé of the research methodology on which the investigation of parent–child argumentation during mealtime is based. In the first part, the conceptual tools adopted for the analysis of argumentative discussions between parents and children, i.e., the pragma-dialectical ideal model of a critical discussion and the Argumentum Model of Topics, are presented. Subsequently, the process of data gathering and the procedures for the transcription of oral data are discussed. Finally, in the last part of the chapter, ethical issues and practical problems in collecting parent–child mealtime conversations present throughout the study are considered

Male reproductive health and environmental xenoestrogens

EHP is a publication of the U.S. government. Publication of EHP lies in the public domain and is therefore without copyright. Research articles from EHP may be used freely; however, articles from the News section of EHP may contain photographs or figures copyrighted by other commercial organizations and individuals that may not be used without obtaining prior approval from both the EHP editors and the holder of the copyright. Use of any materials published in EHP should be acknowledged (for example, "Reproduced with permission from Environmental Health Perspectives") and a reference provided for the article from which the material was reproduced.Male reproductive health has deteriorated in many countries during the last few decades. In the 1990s, declining semen quality has been reported from Belgium, Denmark, France, and Great Britain. The incidence of testicular cancer has increased during the same time incidences of hypospadias and cryptorchidism also appear to be increasing. Similar reproductive problems occur in many wildlife species. There are marked geographic differences in the prevalence of male reproductive disorders. While the reasons for these differences are currently unknown, both clinical and laboratory research suggest that the adverse changes may be inter-related and have a common origin in fetal life or childhood. Exposure of the male fetus to supranormal levels of estrogens, such as diethlylstilbestrol, can result in the above-mentioned reproductive defects. The growing number of reports demonstrating that common environmental contaminants and natural factors possess estrogenic activity presents the working hypothesis that the adverse trends in male reproductive health may be, at least in part, associated with exposure to estrogenic or other hormonally active (e.g., antiandrogenic) environmental chemicals during fetal and childhood development. An extensive research program is needed to understand the extent of the problem, its underlying etiology, and the development of a strategy for prevention and intervention.Supported by EU Contract BMH4-CT96-0314

An image-based visual strategy for working with color contrasts during design

acceptedVersio

Optimal treatment duration of glyceryl trinitrate for chronic anal fissure: results of a prospective randomized multicenter trial

Background: Chronic anal fissure (CAF) is a painful condition that is unlikely to resolve with conventional conservative management. Previous studies have reported that topical treatment of CAF with glyceryl trinitrate (GTN) reduces pain and promotes healing, but optimal treatment duration is unknown. Methods: To assess the effect of different treatment durations on CAF, we designed a prospective randomized trial comparing 40 versus 80 days with twice daily topical 0.4% GTN treatment (Rectogesic®, Prostrakan Group). Chronicity was defined by the presence of both morphological (fibrosis, skin tag, exposed sphincter, hypertrophied anal papilla) and time criteria (symptoms present for more than 2 months or pain of less duration but similar episodes in the past). A gravity score (1 = no visible sphincter; 2 = visible sphincter; 3 = visible sphincter and fibrosis) was used at baseline. Fissure healing, the primary endpoint of the study, maximum pain at defecation measured with VAS and maximum anal resting pressure were assessed at baseline and at 14, 28, 40 and 80 days. Data was gathered at the end of the assigned treatment. Results: Of 188 patients with chronic fissure, 96 were randomized to the 40-day group and 92 to the 80-day group. Patients were well matched for sex, age, VAS and fissure score. There were 34 (19%) patients who did not complete treatment, 18 (10%) because of side effects. Of 154 patients who completed treatment, 90 (58%) had their fissures healed and 105 (68%) were pain free. There was no difference in healing or symptoms between the 40- and the 80-day group. There was no predictor of fissure healing. A low fissure gravity score correlated with increased resolution of pain (P < 0.05) and improvement of VAS score (P < 0.05) on both univariate and multivariate analysis. A lower baseline resting pressure was associated with better pain resolution on univariate analysis (P < 0.01). VAS at defecation and fissure healing significantly improved until 40 days (P < 0.001), while the difference between 40 and 80 days was not significant. Conclusion: We found no benefits in treating CAF with topical GTN for 80 days compared to 40 days. Fissure healing and VAS improvement continue until 6 weeks of treatment but are unlikely thereafter. © 2010 Springer-Verlag

Adenovirus-mediated hypoxia-targeting cytosine deaminase gene therapy enhances radiotherapy in tumour xenografts

Hypoxia is closely associated with the radioresistance of tumours; therefore, targeting hypoxic areas is very important for cancer therapy. The aim of this study is to establish such a targeting strategy by applying a bacterial cytosine deaminase (BCD)/5-fluorocytosine (5-FC) gene therapy system and to examine whether the strategy enhances the efficacy of radiotherapy in a tumour xenograft. The hypoxia-responsive promoter 5HREp, in which five copies of the hypoxia-response element (HRE) enhance transcription from a cytomegalovirus minimal promoter, was employed to induce the expression of BCD under hypoxic conditions. The adenoviral vector Ad/5HREp-BCD, encoding the gene 5HREp-BCD, robustly induced BCD expression under hypoxic conditions and this led to significant cytotoxicity in combination with 5-FC in vitro. Intratumoral Ad/5HREp-BCD administration resulted in the expression of BCD at the border between normoxic and necrotic regions. The BCD/5-FC gene therapy enhanced the therapeutic effects of both single (12.5 Gy) and fractionated (3 Gy × 5 days) radiotherapy with few side effects and significantly increased tumour growth doubling time by up to 2.4-fold (P<0.01) and 2.5-fold (P<0.05), respectively. All of these results suggest that the present BCD/5-FC gene therapy has the ability to specifically target hypoxic tumour cells and significantly improves the control of tumour growth after radiotherapy