The Synthesis of Peptide-Based Tools for Drug Discovery and Chemical-Biology Applications

Peptidyl mono-fluoromethyl ketones (mFMK) are a class of compounds that have shown potential as protease inhibitors for the treatment of a range of diseases. They have also found application as chemical-biology probes that can be used in the interrogation of cellular processes. Despite the aforementioned applications, the number of synthetically viable routes reported for accessing these compounds is currently rather limited. To address this issue, the work herein reports the efforts that have been made towards developing a novel synthetic pathway for preparing mFMKs. Initial attempts (Chapter 2) involved the formation of a tri-carbonyl system derived from a Boc-protected amino acid and Meldrum’s acid, with the intention of subsequently fluorinating, converting to the corresponding β-ketoester and coupling to a peptide of choice in solution. The idea was that the resulting substrate could then be saponified and decarboxylated, allowing access to the fluoromethyl ketone (FMK). However, the inherent reactivity of the moisture-sensitive fluorinated tri-carbonyl systems made them difficult to handle and isolate. Attention was therefore turned towards the direct electrophilic fluorination of β-ketoesters, derived from either an N-Fmoc (Chapter 3) or N-Boc-protected (Chapter 4) amino acid of choice and formed as the tert-butyl ester. Selective mono-fluorination of the resulting 1,3-dicarbonyl was then achieved using CpTiCl3 in conjunction with Selectfluor, through utilisation of adapted literature protocols. The resulting N-Fmoc-protected substrate was carefully transformed to the β-ketoacid (Chapter 3) before attempted resin loading was performed, with the intention of allowing on-resin peptide growth followed by concomitant resin cleavage, global deprotection and decarboxylation to the FMK. However, unsuccessful resin loading attempts, coupled with evidence for premature FMK formation having occurred during these endeavours, suggested the presence of the fluorine atom had significantly reduced the nucleophilicity of the carboxylate, thus favouring decarboxylation over resin loading. Given the challenges encountered with resin loading, the application of N-Boc-protected mono-fluorinated β-ketoesters in solution-phase peptide chemistry was explored (Chapter 4). Selective removal of the N-Boc group in the presence of the tert-butyl ester, through the modification of conditions reported in the literature, enabled coupling to a peptide of choice. Subsequent deprotection and decarboxylation led to the desired FMK. Whilst some epimerisation did appear to occur during peptide coupling, this route represents a straightforward approach for accessing these desirable and highly expensive molecular warheads in only 5 steps. A slightly adapted approach, in which the N-Boc protected β-ketoester was first decarboxylated to the corresponding FMK prior to peptide coupling in solution, was also trialled (Chapter 4). However, this appeared to lead to challenges in purification of the resultant mFMKs, along with an accompanying low yield. Nonetheless, this methodology was successfully adapted and utilised for the synthesis of a peptidyl mono-chloromethyl ketone (mCMK) in only four steps (Chapter 5), although epimerisation was apparent. Furthermore, it is believed that extension of this methodology could allow access to other peptide-based C-terminal modified species, such as peptidyl bromomethyl ketones and di-fluoromethyl ketones. In summary, the methodology developed for accessing both peptidyl mono-fluoromethyl ketones and peptidyl mono-chloromethyl ketones offers ready access to chemical-probes that can be used to interrogate cellular functions in a range of disease relevant systems

Friendship Bench trial: lay worker training in problem-solving therapy to reduce symptoms of common mental disorders

The Friendship Bench trial is a cluster-randomised trial of the effect of problem-solving therapy training for lay workers on symptoms of common mental disorders among clinic attenders in Harare, Zimbabwe. This dataset enables replication of analysis for a paper on suicidal ideation, but has undergone anonymisation process to protect study participants. 12 primary care clinics in Harare were randomised 1:1 to intervention or control. In each clinic, 24 participants were enrolled who were: visiting the clinic (either for their own health needs or accompanying someone else); aged 18 or over; living locally; and screened positive for common mental disorder symptoms. Outcomes were measured after 6 months. 86% of participants were women, 42% were HIV positive and 91% completed follow-up

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This is an electronic version of an article published in Addiction: Complete citation information for the final version of the paper, as published in the print edition of Addiction, is available on the Blackwell Synergy online delivery service, accessible via the journal’s Web site a

Rituximab in autoimmune connective tissue disease–associated interstitial lung disease

Objective. CTD-associated interstitial lung disease (ILD) often fails to respond to conventional immunomodulatory agents. There is now considerable interest in the use of rituximab in systemic autoimmune CTD in patients refractory to standard treatments. The aim of this study was to review the experience of North Bristol NHS Trust managing patients with CTD-associated ILD with rituximab and explore possible associations with treatment response. Methods. We conducted a retrospective analysis of all patients who received rituximab under the Bristol CTD-ILD service, having failed to respond to other immunomodulatory treatments. Results were collated for pulmonary function and radiological outcomes before and after treatment. Results. Twenty-four patients were treated with rituximab. Their physiological parameters had failed to improve despite other immunomodulatory agents, with a mean change in forced vital capacity (FVC) prior to therapy of − 3.3% (95% CI − 5.6, −1.1) and mean change in diffusing capacity of carbon monoxide of − 4.3% (95% CI − 7.7, −0.9). After rituximab, radiology remained stable or improved for 11 patients, while worsening was observed in 9 patients. The decline in FVC was halted following treatment, with a mean change of + 4.1% (95% CI 0.9, 7.2), while diffusing capacity of carbon monoxide was stable [mean change +2.1% (95% CI − 1.0, 5.2)]. Patients with myositis overlap or antisynthetase syndrome appeared to respond well to treatment, with four patients showing clinically significant improvement in FVC >10%. Conclusion. Rituximab is a therapeutic option in treatment-refractory CTD-associated ILD. Some disease subgroups may respond better than others, however, more work is needed to define its role in managing these patients

Evaluation of a library of FDA-approved drugs for their ability to potentiate antibiotics against multidrug resistant Gram-negative pathogens

The Prestwick library was screened for antibacterial activity or 'antibiotic-resistance breaking' (ARB) potential against four species of Gram-negative pathogens. Discounting known antibacterials, the screen identified very few ARB hits, which were strain/drug specific. These ARB hits included antimetabolites (zidovudine, floxuridine, didanosine, gemcitabine), anthracyclines (daunorubicin, mitoxantrone, epirubicin) and psychoactive drugs (gabapentin, fluspirilene, oxethazaine). This suggests that there are few approved drugs which could be directly repositioned as adjunct-antibacterials and these will need robust testing to validate efficacy. [Abstract copyright: © Crown copyright 2019.

Effects of pre-colonisation and temperature on interspecific fungal interactions in wood

Understanding the effects of changing abiotic conditions on assembly history in wood decay communities is especially important with predicted environmental changes. Interspecific interactions drive community development, so it is important to understand how microclimatic environment affects outcomes of interactions between species from different successional stages in natural substrata. Interactions between eight wood decay fungi were performed in beech (Fagus sylvatica) wood at seven temperatures (12–30 °C), and in soil microcosms and wood that had been pre-colonised for different lengths of time. The hierarchy of combative ability could be altered by changes in temperature: at higher temperatures early secondary colonisers were able to outcompete usually later colonising cord-forming species. Length of pre-colonisation had a species-specific effect on combative ability, probably attributable to biochemical changes rather than the state of decay of the resource. Abiotic variables have clear effects on fungal interactions, underlining the importance of stochastic factors in fungal community succession

Trained lay health workers reduce common mental disorder symptoms of adults with suicidal ideation in Zimbabwe: a cohort study.

BACKGROUND: Suicidal ideation may lead to deliberate self-harm which increases the risk of death by suicide. Globally, the main cause of deliberate self-harm is depression. The aim of this study was to explore prevalence of, and risk factors for, suicidal ideation among men and women with common mental disorder (CMD) symptoms attending public clinics in Zimbabwe, and to determine whether problem solving therapy delivered by lay health workers can reduce common mental disorder symptoms among people with suicidal ideation, using secondary analysis of a randomised controlled trial. METHODS: At trial enrolment, the Shona Symptom Questionnaire (SSQ) was used to screen for CMD symptoms. In the intervention arm, participants received six problem-solving therapy sessions conducted by trained and supervised lay health workers, while those in the control arm received enhanced usual care. We used multivariate logistic regression to identify risk factors for suicidal ideation at enrolment, and cluster-level logistic regression to compare SSQ scores at endline (6 months follow-up) between trial arms, stratified by suicidal ideation at enrolment. RESULTS: There were 573 participants who screened positive for CMD symptoms and 75 (13.1%) reported suicidal ideation at baseline. At baseline, after adjusting for confounders, suicidal ideation was independently associated with being aged over 24, lack of household income (household income yes/no; adjusted odds ratio 0.52 (95% CI 0.29, 0.95); p = 0.03) and with having recently skipped a meal due to lack of food (adjusted odds ratio 3.06 (95% CI 1.81, 5.18); p < 0.001). Participants who reported suicidal ideation at enrolment experienced similar benefit to CMD symptoms from the Friendship Bench intervention (adjusted mean difference - 5.38, 95% CI -7.85, - 2.90; p < 0.001) compared to those who had common mental disorder symptoms but no suicidal ideation (adjusted mean difference - 4.86, 95% CI -5.68, - 4.04; p < 0.001). CONCLUSIONS: Problem-solving therapy delivered by trained and supervised lay health workers reduced common mental disorder symptoms among participants with suicidal thoughts who attended primary care facilities in Zimbabwe. TRIAL REGISTRATION: pactr.org ldentifier: PACTR201410000876178

Trends in Recall and Appraisal of Anti-Smoking Advertising Among American Youth: National Survey Results, 1997–2001

Public health efforts to reduce the harms related to tobacco use currently include a significant emphasis on anti-smoking media campaigns. This paper provides (a) data on the overall extent of exposure to anti-smoking media among American youth from 1997 to 2001, (b) an appraisal of general youth reactions to such advertising, and (c) an examination of how exposure levels and reactions vary by socio-demographic characteristics. Data were obtained from the Monitoring the Future study, an ongoing nationwide study of youth. Data were collected each year from nationally representative separate and nonoverlapping school samples of 8th, 10th, and 12th grade students ( N = 29,724; 24,639; and 12,138, respectively). Self-reported levels of recalled exposure to both electronic and print anti-smoking advertising were measured, as well as the judged impact and perceived exaggeration of such advertising. Data indicate that significant increases in overall exposure to anti-smoking advertising occurred over the study time period. These increases were associated with (a) increases in the self-reported likelihood that anti-smoking advertising diminished the probability of individual smoking behaviors, and (b) increases in the perceived level to which anti-smoking advertising exaggerates the risks associated with smoking. Further, these trends were significantly associated with various characteristics—most notably, ethnicity, smoking behaviors, and residence in a state with an ongoing tobacco-control program having a media component.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45502/1/11121_2005_Article_NY00001249.pd

A multi-scalar perspective on health and urban housing: an umbrella review

With more than half the world’s population living in cities, understanding how the built environment impacts human health at different urban scales is crucial. To be able to shape cities for health, an understanding is needed of planetary health impacts, which encompass the human health impacts of human-caused disruptions on the Earth’s natural ecosystems. This umbrella review maps health evidence across the spatial scales of the built environment (building; neighbourhood; and wider system, including city, regional and planetary levels), with a specific focus on urban housing. Systematic reviews published in English between January 2011 and December 2020 were searched across 20 databases, with 1176 articles identified and 124 articles screened for inclusion. Findings suggests that most evidence reports on health determinants at the neighbourhood level, such as greenspace, physical and socio-economic conditions, transport infrastructure and access to local services. Physical health outcomes are also primarily reported, with an emerging interest in mental health outcomes. There is little evidence on planetary health outcomes and significant gaps in the research literature are identified. Based on these findings, three potential directions are identified for future research