111 research outputs found

    A Strategy for Imidazotetrazine Prodrugs with Anti-cancer Activity Independent of MGMT and MMR

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    The imidazotetrazine ring is an acid-stable precursor and prodrug of highly-reactive alkyl diazonium ions. We have shown that this reactivity can be managed productively in an aqueous system for the generation of aziridinium ions with 96% efficiency. The new compounds are potent DNA alkylators and have antitumor activity independent of the O6-methylguanine-DNA methyltransferase and DNA mismatch repair constraints that limit the use of temozolomide

    Limits of 'patient-centredness'; valuing contextually specific communication patterns

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    Context Globally, doctor–patient communication is becoming synonymous with high-quality health care in the 21st century. However, what is meant by ‘good communication’ and whether there is consensus internationally remain unclear. Objectives Here, we characterise understandings of ‘good communication’ in future doctors from medical schools in three contextually contrasting continents. Given locally specific socio-cultural influences, we hypothesised that there would be a lack of global consensus on what constitutes ‘good communication’. Methods A standardised two-phase methodology was applied in turn to each of three medical schools in the UK, Egypt and India (n = 107 subjects), respectively, in which students were asked: ‘What is good communication?’ Phase I involved exploratory focus groups to define preliminary themes (mean number of participants per site: 17). Phase II involved thematic confirmation and expansion in one-to-one semi-structured interviews (mean number of participants per site: 18; mean hours of dialogue captured per site: 55). Findings were triangulated and analysed using grounded theory. Results The overarching theme that emerged from medical students was that ‘good communication’ requires adherence to certain ‘rules of communication’. A shared rule that doctors must communicate effectively despite perceived disempowerment emerged across all sites. However, contradictory culturally specific rules about communication were identified in relation to three major domains: family; gender, and emotional expression. Egyptian students perceived emotional aspects of Western doctors’ communication strikingly negatively, viewing these doctors as problematically cold and unresponsive. Conclusions Contradictory perceptions of ‘good communication’ in future doctors are found cross-continentally and may contribute to prevalent cultural misunderstandings in medicine. The lack of global consensus on what defines good communication challenges prescriptively taught Western ‘patient-centredness’ and questions assumptions about international transferability. Health care professionals must be educated openly about flexible, context-specific communication patterns so that they can avoid cultural incompetence and tailor behaviours in ways that optimise therapeutic outcomes wherever they work around the globe

    Evaluation of Novel Imidazotetrazine Analogues Designed to Overcome Temozolomide Resistance and Glioblastoma Regrowth

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    The cellular responses to two new temozolomide (TMZ) analogues, DP68 and DP86, acting against glioblastoma multi- forme (GBM) cell lines and primary culture models are reported. Dose–response analysis of cultured GBM cells revealed that DP68 is more potent than DP86 and TMZ and that DP68 was effective even in cell lines resistant to TMZ. On the basis of a serial neurosphere assay, DP68 inhibits repop- ulation of these cultures at low concentrations. The efficacy of these compounds was independent of MGMT and MMR func- tions. DP68-induced interstrand DNA cross-links were dem- onstrated with H2O2-treated cells. Furthermore, DP68 induced a distinct cell–cycle arrest with accumulation of cells in S phase that is not observed for TMZ. Consistent with this biologic response, DP68 induces a strong DNA damage response, including phosphorylation of ATM, Chk1 and Chk2 kinases, KAP1, and histone variant H2AX. Suppression of FANCD2 expression or ATR expression/kinase activity enhanced anti- glioblastoma effects of DP68. Initial pharmacokinetic analysis revealed rapid elimination of these drugs from serum. Collec- tively, these data demonstrate that DP68 is a novel and potent antiglioblastoma compound that circumvents TMZ resistance, likely as a result of its independence from MGMT and mismatch repair and its capacity to cross-link strands of DN

    Synthesis and Quantitative Structure–Activity Relationship of Imidazotetrazine Prodrugs with Activity Independent of O6-Methylguanine-DNA-methyltransferase, DNA Mismatch Repair and p53.

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    The antitumor prodrug Temozolomide is compromised by its dependence for activity on DNA mismatch repair (MMR) and the repair of the chemosensitive DNA lesion, O6-methylguanine (O6-MeG), by O6-methylguanine-DNA-methyltransferase (EC 2.1.1.63, MGMT). Tumor response is also dependent on wild-type p53. Novel 3-(2-anilinoethyl)-substituted imidazotetrazines are reported that have activity independent of MGMT, MMR and p53. This is achieved through a switch of mechanism so that bioactivity derives from imidazotetrazine-generated arylaziridinium ions that principally modify guanine-N7 sites on DNA. Mono- and bi-functional analogs are reported and a quantitative structure-activity relationship (QSAR) study identified the p-tolyl-substituted bi-functional congener as optimized for potency, MGMT-independence and MMR-independence. NCI60 data show the tumor cell response is distinct from other imidazotetrazines and DNA-guanine-N7 active agents such as nitrogen mustards and cisplatin. The new imidazotetrazine compounds are promising agents for further development and their improved in vitro activity validates the principles on which they were designed

    The Depression: Online Therapy Study (D:OTS)—A Pilot Study of an Internet-Based Psychodynamic Treatment for Adolescents with Low Mood in the UK, in the Context of the COVID-19 Pandemic

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    Introduction: Face-to-face therapy is unavailable to many young people with mental health difficulties in the UK. Internet-based treatments are a low-cost, flexible, and accessible option that may be acceptable to young people. This pilot study examined the feasibility, acceptability and effectiveness of an English-language adaptation of internet-based psychodynamic treatment (iPDT) for depressed adolescents, undertaken during the COVID-19 pandemic in the UK. Methods: A single-group, uncontrolled design was used. A total of 23 adolescents, 16–18 years old and experiencing depression, were recruited to this study. Assessments were made at baseline and end of treatment, with additional weekly assessments of depression and anxiety symptoms. Results: Findings showed that it was feasible to recruit to this study during the pandemic, and to deliver the iPDT model with a good level of treatment acceptability. A statistically significant reduction in depressive symptoms and emotion dysregulation was found, with large effect size, by the end of treatment. Whilst anxiety symptoms decreased, this did not reach statistical significance. Conclusions: The findings suggest that this English-language adaptation of iPDT, with some further revisions, is feasible to deliver and acceptable for adolescents with depression. Preliminary data indicate that iPDT appears to be effective in reducing depressive symptoms in adolescents

    Chlamydia trachomatis infection increases fallopian tube PROKR2 via TLR2 and NFκB activation resulting in a microenvironment predisposed to ectopic pregnancy

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    Chlamydia trachomatis and smoking are major risk factors for tubal ectopic pregnancy (EP), but the underlying mechanisms of these associations are not completely understood. Fallopian tube (FT) from women with EP exhibit altered expression of prokineticin receptors 1 and 2 (PROKR1 and PROKR2); smoking increases FT PROKR1, resulting in a microenvironment predisposed to EP. We hypothesize that C. trachomatis also predisposes to EP by altering FT PROKR expression and have investigated this by examining NFkappaB activation via ligation of the Toll-like receptor (TLR) family of cell-surface pattern recognition receptors. PROKR2 mRNA was higher in FT from women with evidence of past C. trachomatis infection than in those without (P < 0.05), and was also increased in FT explants and in oviductal epithelial cell line OE-E6/E7 infected with C. trachomatis (P < 0.01) or exposed to UV-killed organisms (P < 0.05). The ability of both live and dead organisms to induce this effect suggests ligation of a cell-surface-expressed receptor. FT epithelium and OE-E6/E7 were both found to express TLR2 and TLR4 by immunohistochemistry. Transfection of OE-E6/E7 cells with dominant-negative TLR2 or IkappaBalpha abrogated the C. trachomatis-induced PROKR2 expression. We propose that ligation of tubal TLR2 and activation of NFkappaB by C. trachomatis leads to increased tubal PROKR2, thereby predisposing the tubal microenvironment to ectopic implantation

    Dual EGFR and mTOR targeting in squamous cell carcinoma models, and development of early markers of efficacy

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    The epidermal growth factor receptor (EGFR) is a validated target in squamous cell carcinoma (SCC) of the head and neck. Most patients, however, do not respond or develop resistance to this agent. Mammalian target of rapamycin (mTOR) is involved in the pathogenesis of SCC of the head and neck (SCCHN). This study aimed to determine if targeting mTOR in combination with EGFR is effective in SCC, and to develop early pharmacodynamic markers of efficacy. Two SCC cell lines, one resistant (HEP2) and one of intermediate susceptibility (Detroit 562) to EGFR inhibitors, were xenografted in vivo and treated with an mTOR inhibitor (temsirolimus), an EGFR inhibitor (erlotinib) or a combination of both. Temsirolimus exerted superior growth arrest in both cell lines than erlotinib. The combined treatment resulted in synergistic antitumor effects in the Detroit 562 cell line. Immunohistochemical assessment of pharmacodynamic effects in fine-needle aspiration (FNA) biopsies early after treatment using phospho MAPK, Phospho-P70 and Ki67 as end points demonstrated pathway abrogation in the Detroit 562 tumours treated with the combination, the only group where regressions were seen. In conclusion, an mTOR inhibitor showed antitumor activity in EGFR-resistant SCC cell lines. Marked antitumor effects were associated with dual pathway inhibition, which were detected by early FNA biopsies

    The conceptual design of CLARA, a novel fel test facility for ultra-short pulse generation

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    CLARA will be a novel FEL test facility focussed on the generation of ultra-short photon pulses with extreme levels of stability and synchronisation. The principal aim is to experimentally demonstrate that sub-cooperation length pulse generation with FELs is viable, and to compare the various schemes being championed. The results will translate directly to existing and future X-ray FELs, enabling them to generate attosecond pulses, thereby extending their science capabilities. This paper gives an overview of the motivation for CLARA, describes the facility design (reported in detail in the recently published Conceptual Design Report [1]) and proposed operating modes and summarises the proposed areas of FEL research
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