Studies of some antiparasitic agents

Each year, between 300 and 500 million people develop malaria. Close to 3 million people die as a result. Due to resistance there are now few drugs left which are effective against malaria; one is a Chinese herbal remedy called qinghaosu (artemisinin). A section of this thesis represents an attempt to understand further the mode of action of this antimalarial agent. Several mechanisms involving iron have been proposed and the main categories reviewed (chapter 3). Techniques including ESR spectrometry, fluorescence and absorbance measurements were used to further probe the mode of action of qinghaosu. The findings of these studies provide support for a mechanism proposed by Wu et al., involving cleavage of the peroxy bridge in qinghaosu with the ferrous ion as opposed to antimalarial activity being due to the generation of high valent iron-oxo species. The ether derivative of qinghaosu, arteether has been studied using 2D NMR in order to provide further insight into the unusual structure of this compound (chapter 4). A comparison of the sp2 lactone functionality in qinghaosu with the sp3 ether group in arteether was performed. Evidence is presented for different conformations and chemical shift values. The immune system protects the human body from invasion by foreign substances or cells. A key part of this immune response comes from cellular components known as macrophages. The killing process of macrophages appears to involve nitric oxide. However, this natural defence mechanism is not very efficient as the body is susceptible to invasion by microbes. The term microbe includes both parasites and bacteria. The toxicity of nitric oxide (NO) and NO donor compounds has been investigated using the bacterium E. coli (chapter 5). In addition, studies have been performed using parasites. Malarial parasites (Plasmodia) are difficult to culture, therefore Leishmania parasites which cause the tropical disease leishmaniasis were used as a model (chapter 6). Evidence is presented for the toxic nature of NO donor compounds towards both parasites and bacteria. However, qinghaosu and its derivatives did not prove effective against Leishmania mexicana parasites in contrast with their reported antimalarial activity. The conclusions of this study suggest that qinghaosu possesses a toxicity mechanism selective for malarial parasites

Environmental interventions to reduce fear of crime: systematic review of effectiveness

Background: Fear of crime is associated with negative health and wellbeing outcomes, and may mediate some impacts of the built environment on public health. A range of environmental interventions have been hypothesized to reduce the fear of crime. Methods: This review aimed to synthesize the literature on the effectiveness of interventions in the built environment to reduce the fear of crime. Systematic review methodology, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidance, was used. Studies of environmental interventions which reported a fear of crime outcome and used any prospective evaluation design (randomized controlled trial (RCT), trial or uncontrolled before-and-after study) were included. Eighteen databases were searched. The Hamilton tool was used to assess quality. A narrative synthesis of findings was undertaken. Results: A total of 47 studies were included, 22 controlled and 25 uncontrolled, with total sample sizes ranging from n = 52 to approximately n = 23,000. Thirty-six studies were conducted in the UK, ten studies in the USA and one study in the Netherlands. The quality of the evidence overall is low. There are some indications that home security improvements and non-crime-related environmental improvements may be effective for some fear of crime outcomes. There is little evidence that the following reduce fear of crime: street lighting improvements, closed-circuit television (CCTV), multi-component environmental crime prevention programs or regeneration programs. Conclusions: There is some evidence for the effectiveness of specific environmental interventions in reducing some indicators of fear of crime, but more attention to the context and possible confounders is needed in future evaluations of complex social interventions such as these

Definition and assessment of paediatric breakthrough pain: A qualitative interview study

Infants, children and young people with life-limiting or life-threatening conditions often experience acute, transient pain episodes known as breakthrough pain. There is currently no established way to assess breakthrough pain in paediatric palliative care. Anecdotal evidence suggests that it is frequently underdiagnosed and undertreated, resulting in reduced quality of life. The development of a standardised paediatric breakthrough pain assessment, based on healthcare professionals’ insights, could improve patient outcomes. This study aimed to explore how healthcare professionals define and assess breakthrough pain in paediatric palliative care and their attitudes towards a validated paediatric breakthrough pain assessment. This was a descriptive qualitative interview study. Semi-structured interviews were conducted with 29 healthcare professionals working in paediatric palliative care across the UK. An inductive thematic analysis was conducted on the data. Five themes were generated: ‘the elusive nature of breakthrough pain,’ ‘breakthrough pain assessment,’ ‘positive attitudes towards’, ‘reservations towards’ and ‘features to include in’ a paediatric breakthrough pain assessment. The definition and assessment of breakthrough pain is inconsistent in paediatric palliative care. There is a clear need for a validated assessment questionnaire to improve assessment, diagnosis and management of breakthrough pain followed by increased healthcare professional education on the concept

A rapid systematic review of breakthrough pain definitions and descriptions

Background Breakthrough pain is common in life-limiting conditions and at end-of-life. Despite over 30 years of study, there is little consensus regarding the definition and characteristics of breakthrough pain. Objective This study aims to update and expand a 2010 systematic review by Haugen and colleagues to identify (1) all definitions of breakthrough pain and (2) all descriptions and classifications of breakthrough pain reported by patients, caregivers, clinicians, and experts. Design This rapid systematic review followed the Cochrane Rapid Review Methods Group guidelines. A protocol is published on PROSPERO (CRD42019155583). Data sources CINAHL, MEDLINE, PsycINFO, and the Web of Science were searched for breakthrough pain terms from the inception dates of each database to 26th August 2022. Results We identified 65 studies that included data on breakthrough pain definitions, descriptions, or classifications from patients ( n = 30), clinicians ( n = 6), and experts ( n = 29), but none with data from caregivers. Most experts proposed that breakthrough pain was a sudden, severe, brief pain occurring in patients with adequately controlled mild-moderate background pain. However, definitions varied and there was no consensus. Pain characteristics were broadly similar across studies though temporal factors varied widely. Experts classified breakthrough pain into nociceptive, neuropathic, visceral, somatic, or mixed types. Patients with breakthrough pain commonly experienced depression, anxiety, and interference with daily life. Conclusions Despite ongoing efforts, there is still no consensus on the definition of breakthrough pain. A compromise is needed on breakthrough pain nomenclature to collect reliable incidence and prevalence data and to inform further refinement of the construct

Genome-wide association studies of autoimmune vitiligo identify 23 new risk loci and highlight key pathways and regulatory variants

Vitiligo is an autoimmune disease in which depigmented skin results from the destruction of melanocytes1, with epidemiological association with other autoimmune diseases2. In previous linkage and genome-wide association studies (GWAS1 and GWAS2), we identified 27 vitiligo susceptibility loci in patients of European ancestry. We carried out a third GWAS (GWAS3) in European-ancestry subjects, with augmented GWAS1 and GWAS2 controls, genome-wide imputation, and meta-analysis of all three GWAS, followed by an independent replication. The combined analyses, with 4,680 cases and 39,586 controls, identified 23 new significantly associated loci and 7 suggestive loci. Most encode immune and apoptotic regulators, with some also associated with other autoimmune diseases, as well as several melanocyte regulators. Bioinformatic analyses indicate a predominance of causal regulatory variation, some of which corresponds to expression quantitative trait loci (eQTLs) at these loci. Together, the identified genes provide a framework for the genetic architecture and pathobiology of vitiligo, highlight relationships with other autoimmune diseases and melanoma, and offer potential targets for treatment

A common haplotype lowers PU.1 expression in myeloid cells and delays onset of Alzheimer's disease

A genome-wide survival analysis of 14,406 Alzheimer's disease (AD) cases and 25,849 controls identified eight previously reported AD risk loci and 14 novel loci associated with age at onset. Linkage disequilibrium score regression of 220 cell types implicated the regulation of myeloid gene expression in AD risk. The minor allele of rs1057233 (G), within the previously reported CELF1 AD risk locus, showed association with delayed AD onset and lower expression of SPI1 in monocytes and macrophages. SPI1 encodes PU.1, a transcription factor critical for myeloid cell development and function. AD heritability was enriched within the PU.1 cistrome, implicating a myeloid PU.1 target gene network in AD. Finally, experimentally altered PU.1 levels affected the expression of mouse orthologs of many AD risk genes and the phagocytic activity of mouse microglial cells. Our results suggest that lower SPI1 expression reduces AD risk by regulating myeloid gene expression and cell function

Psychosocial impact of undergoing prostate cancer screening for men with BRCA1 or BRCA2 mutations.

OBJECTIVES: To report the baseline results of a longitudinal psychosocial study that forms part of the IMPACT study, a multi-national investigation of targeted prostate cancer (PCa) screening among men with a known pathogenic germline mutation in the BRCA1 or BRCA2 genes. PARTICPANTS AND METHODS: Men enrolled in the IMPACT study were invited to complete a questionnaire at collaborating sites prior to each annual screening visit. The questionnaire included sociodemographic characteristics and the following measures: the Hospital Anxiety and Depression Scale (HADS), Impact of Event Scale (IES), 36-item short-form health survey (SF-36), Memorial Anxiety Scale for Prostate Cancer, Cancer Worry Scale-Revised, risk perception and knowledge. The results of the baseline questionnaire are presented. RESULTS: A total of 432 men completed questionnaires: 98 and 160 had mutations in BRCA1 and BRCA2 genes, respectively, and 174 were controls (familial mutation negative). Participants' perception of PCa risk was influenced by genetic status. Knowledge levels were high and unrelated to genetic status. Mean scores for the HADS and SF-36 were within reported general population norms and mean IES scores were within normal range. IES mean intrusion and avoidance scores were significantly higher in BRCA1/BRCA2 carriers than in controls and were higher in men with increased PCa risk perception. At the multivariate level, risk perception contributed more significantly to variance in IES scores than genetic status. CONCLUSION: This is the first study to report the psychosocial profile of men with BRCA1/BRCA2 mutations undergoing PCa screening. No clinically concerning levels of general or cancer-specific distress or poor quality of life were detected in the cohort as a whole. A small subset of participants reported higher levels of distress, suggesting the need for healthcare professionals offering PCa screening to identify these risk factors and offer additional information and support to men seeking PCa screening