Management of leg ulceration is an important part of community nurses’ workload but previous evidence suggests the quality of diagnosis and treatment of venous leg ulceration may be below that which should be expected. This thesis uses Judgement Analysis and Think Aloud methodologies to explore the performance of 18 tissue viability specialist nurses and 18 generalist community nurses managing patients with leg ulceration. The nurses made diagnostic judgements and treatment choices and assigned confidence ratings on 110 clinical scenarios generated from real patient cases. These were presented online, as written scenarios, and using photographs of wounds to add visual information. Data for the judgement ‘ecology’ was derived from consensus judgements of a group of ‘expert’ nurses using the same scenarios. Logistic regression models were constructed to examine ideographic Lens Model statistics for individual nurses. Comparisons were made between groups of nurses with different levels of education and expertise. Think Aloud data from three generalist nurses was analysed to identify their cognitive processes. The results showed that clinical decisions and judgements about venous leg ulceration are made in uncertain decision environments. In this study, community nurses achieved levels of accuracy below the achievable levels of judgement accuracy indicated by the diagnostic and treatment ecology models. Education alone was not a predictor of superior clinical performance. The ABPI was an important but under-weighted cue in diagnosis and the diagnosis (as a cue) was an important but under-weighted cue in treatment choice. Despite high levels of experience, nurses were under-confident in their judgements. A range of cognitive approaches to reasoning were apparent. The main contribution of this thesis is exposing the complexity of the clinical environment for leg ulceration and in setting out models for diagnostic judgment and treatment choices for venous leg ulceration. These models provide a starting point for developing robust strategies for supporting community nurses’ judgement and decision making.

Atopic Dermatitis(AD)is recognized as one of the major worldwide health concerns. Despite being first described in the nineteenth century by Besnier, management options continue to be limited and are primarily palliative. AD patients are susceptible to many infections, such as the Herpes simplex virus (HSV), resulting in a more serious clinical subgroup of patients with AD complicated by Eczema Herpeticum (ADEH). Supplementation with vitamiD (VD)has shown positive effects on the clinical outcome of AD in previous randomized controlled trials and clinical studies which could be due, in part, to the up regulation the antimicrobial peptide LL‐37, which has known antimicrobial, immune-­modulatory and wound healing effects. Objective: We sought to determine the level of VD deficiency in AD and ADEH patients in a pediatric dermatology clinic,to investigate whether there was a difference in baseline VD levels between AD and ADEH, to examine skin surface LL-­37 levels in both and to establish whether VD supplementation would result in clinical improvement. Methods: A practice evaluation study was performed at the Sheffield Children’s Hospital. All AD patients were screened for VD deficiency. Those that were found deficient were assessed using SCORAD and POEM. Skin surface cells were collected from lesional and non-­lesional sites using a novel non-invasive technique for LL-­37 evaluation. In addition, serum IgE levels and serum calcium levels were also checked. Supplementation was then commenced for two months after which clinical severity was reassessed and all levels were rechecked. Results: Ninety children (mean age9) were screened for VD deficiency; 83% had low VD levels. VD levels were significantly lower in ADEH children than AD children (p <0.0001). Baseline SCORAD was also significantly higher in ADEH patients (p < 0.0001). Skin surface LL-­37 levels were reduced in ADEH patients in comparison to AD patients (p = 0.46), and were significantly reduced in patients with severe AD (SCORAD>50) in comparison to patients with moderate (SCORAD 25-­‐50) or mild AD (SCORAD <25; p=0.018). Two months of VD supplementation resulted in significant improvement of SCORAD (p <0.0001) and POEM (p < 0.0001) in both groups; LL-­37 levels also increased significantly (p = 0.0004). Conclusions: VD deficiency was found to be common in AD children, and VD supplementation reduced ADEH and AD severity in children. Part of the explanation is through increased LL-­37 production.

Sequencing of the genome of Propionibacterium acnes produced a catalogue of genes many of which enable this organism to colonise sites in human skin and survive a range of environmental challenges. However as yet, there is little understanding of the relationships and interactions between genes that give rise to an organism, which has major impact on human health and wellbeing as an opportunistic pathogen that causes infections beyond the skin. To provide a platform for better understanding gene regulation in P. acnes, this thesis shows using microarrays, reproducible genetic responses to external changes relevant to the skin environment in P. acnes can be studied using batch cultures. It then goes on to describe the generation of nucleotide-resolution maps of the primary and secondary transcriptome. The maps were produced by combining differential and global RNA sequencing approaches. Sites of transcriptional initiation, stable RNA processing and mRNA cleavage as well as riboswitches, small non-coding RNAs, vegetative promoters, and previously undetected genes were identified across the genome. In addition, evidence was obtained for the widespread use of leaderless mRNAs, which may be translated by specialised ribosomes. Preliminary evidence for the existence of the latter, in the form of particular ribosomal RNA processing, was obtained. The study also provided statistically robust evidence for pervasive transcription that is associated with both the sense and antisense strands of coding regions. Continuing annotation of the primary and secondary transcriptomes of pathogens will assist comparative and functional genomics approaches and may also aid the modelling of the disease process and therapeutic development.

Chronic leg ulcers affect 1% of the adult population in the developed countries. The majority of leg ulcers are due to venous disease. The impact of venous ulcers on the quality of life is significant, and it costs the NHS £300-600m annually. Medical compression bandages (MCBs) are the cornerstone in the treatment of chronic venous ulcers. MCBs should be applied with a pressure gradient reducing from the ankle to the knee. Visual inspection of bandages in situ for the amount of extension and overlap in the MCBs is normally what nurses use in day by day clinical practice to control the pressure they apply to patients' legs. Interface pressure produced by a bandage is proportional to the tension which, in turn, is proportional to the extension of the bandage, and pressure is inversely proportional to the limb radius. Experts in the field believe that applying MCBs with a constant extension will enable users to achieve the required gradient pressure profile, as the circumference of the leg increases from the ankle towards the mid-calf. Despite the many studies published investigating the effectiveness of different MCBs, very little work has been done to understand the underpinning physics of how MCBs apply pressure to the leg. In addition, although many types of pressure measurement systems have been developed and used by various researchers, most of these devices have not been systematically tested for their performance and measurement reliability. In this thesis, the physics behind compression therapy is investigated and modeled using mathematical equations, some of which are validated experimentally. Analytical results suggest that ignoring MCBs thickness when computing the interface pressure will have a negligible effect on the accuracy of the pressure calculation produced by singlelayer MCBs. However, MCBs thickness should be considered in computing the interface pressure produced by multi-layer MCBs. Moreover, a model developed by other researchers to explain the impact of the pressure sensor's physical dimensions on the interface pressure is tested experimentally. Results suggest that the model is not sufficient to estimate the amount of perturbation in the pressure, and a better model is needed. Furthermore, the thesis outlines experiments conducted to study MCBs and obtain polynomial expressions to describe the MCBs tension-elongation curves. The polynomial expressions are used in conjunction with mathematical models to compute the interface pressure induced by MCBs. In addition, the thesis demonstrates how the information obtained from these experiments is used in line with a mathematical model to classify compression bandages and simulate the impact of limb shape change secondary to calf muscle activity on the interface pressure. Moreover, the thesis reports on the evaluation of various types of resistive-based flexible pressure sensors. It illustrates that FlexiForce outperforms other resistive-based flexible sensors in static evaluation for sensitivity to low pressures, nonlinearity, repeatability, hysteresis and drift. However, the typical accuracy of FlexiForce sensor is found to be 12% full scale, where full scale in this case is 120mmHg. The accuracy error is further reduced to approximately 6% full scale by arranging the sensors in arrays and using averaging techniques. Arrays of FlexiForce sensors are used then to map the interface pressure under MCBs applied to dierent mediums. The pressure maps obtained by FlexiForce sensors are compared with the maps obtained using microelectromechanical systems (MEMS) force sensors and PicoPress transducer, a commercial medical pressure transducer used currently to study the pressure induced under MCBs. Furthermore, the measured pressures in all these cases are compared with the pressures computed theoretically from the bandage extension. Results show low levels of agreement or, in some cases, no agreement between the measured and computed pressures, which lead to question the reliability of using extension as a feedback method to control the interface pressure applied by MCBs. Additionally, in spite of some dfficiencies in the performance of FlexiForce sensors, the thesis demonstrates that they could be used to obtain pressure maps for qualitative purposes. This, in some cases, is found to provide more reliable pressure readings than commercial sensors like PicoPress. Generally, current medical pressure transducers are thick; thus, they tend to overestimate the pressure applied by compression bandages significantly. The thesis details the assessment of pressure-mapping bandage prototypes and the associated tests carried out to evaluate their performance. Preliminary results suggest that the pressure-mapping bandage prototypes cannot be used to have accurate measurements. Nevertheless, they can provide the user with qualitative information about the pressure profile in terms of pressure levels and gradient. Finally, the thesis presents the usage of a pressure-mapping leg for training purposes for student nurses. This involved studying student nurses' bandaging techniques and pinpointing their main bandaging technique pitfalls. Compared with experienced nurses,fewer of the student nurses applied MCBs with reverse pressure gradient.

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No description available.

We have compared the effect of three chemically diverse common irritants on 100 patients with a history of chronic ICD for more than 6 weeks, and 31 normal volunteers. The irritants were titrated on normal skin to induce similar grades of erythema by 48 hours. The final concentrations, 80% nonanoic acid (NA), 5% sodium lauryl sulphate (SLS) and 0.01% dithranol (DL) were applied to the volar aspect of the forearm for various timepoints up to 48 hours. DL irritation evoked minimal histopathological changes. Epidermal damage however, was observed after both NA and SLS application. NA irritation profoundly affected the epidermal LC population, inducing redistribution, apoptosis and a dramatic decrease in LC numbers by 24 hours. Keratinocyte (KC) apoptosis and mild spongiosis was also evident. In contrast SLS irritation had a marked affect upon the epidermal KC population, inducing proliferation, parakeratosis, severe oedema and focal KC activation by 24 and 48 hours. KC activation, defined by MHC II and CD54 expression accompanied an extensive leucocyte exocytosis. SLS irritation also reduced epidermal LC numbers by 48 hours, but not as a result of apoptosis. These findings suggest that for the two irritants different mechanisms are involved in LC reduction and therefore have important implications for antigen presentation and immune responses. KC activation and the resultant leucocyte influx were probably triggered through cytokine production. We suggest that the potent T cell and neutrophil chemoattractant IL-8, present after SLS application, was responsible for the heavy dermal and subsequent epidermal leucocyte influx observed by 24 and 48 hours. In the case of NA irritation leucocyte infiltration was less significant, neutrophils were present in the papillary dermis infiltrate at 6 hours, although this influx was not sustained. In contrast, SLS irritation caused dermal accumulation of larger numbers of neutrophils at 24 and 48 hours.

Irritant contact dermatitis (ICD) is a very common occupational skin disease but its pathogenesis remains poorly understood. The application of topical irritants was used to study cellular mechanisms of ICD, by sampling tissue from skin biopsies, suction blisters and skin window chambers. The early (upto 6h) and late (upto 48h) histopathological changes were investigated in patients following the application of 80% nonanoic acid (NA) and 5% sodium lauryl sulphate (SLS). The irritants were titrated on volunteers to produce similar grades of mild erythema for the two irritants. SLS caused minimal early damage but induced parakeratosis and spongiosis at 24h. SLS also induced a prominent dermal neutrophilic infiltrate and epidermal infiltration. In contrast, NA induced basal cell layer apoptosis without significant inflammatory infiltration. These cells were later shown to be Langerhans cells (LC). The different patterns of epidermal damage prompted the quantification of the cytokines IL-8 (a neutrophil chemoattractant) and IL-1α (a key pro-inflammatory cytokine) by ELISA in suction blister fluid in patients and volunteers after irritation with NA and SLS. It was shown that NA induced IL-1α upto 24h post irritation, but minimal IL-8. SLS, however, induced IL-8 at 6 and 24h. This result was in keeping with the histopathological findings above. Another aspect of ICD studied was the investigation of LC after NA irritation by confocal microscopy, in both volunteers and patients with ICD. There was a marked reduction of LC in both groups, but greater in patients. The morphology of the LC was altered with a reduction in both the number and lengths of dendrites with time after irritation.

Atopic eczema has a profound negative impact on patients and their families and improved therapeutic options are required. Although, the pathogenesis is still not fully understood, evidence of a primary barrier defect predisposing to increased stimulation of the innate and adaptive immune system increases. Cyclosporine A (CsA) is an effective therapy for inflammatory skin disease. CsA binds to cyclophilin B (CypB) with high affinity, mediating T-cell immunosuppression. CsA also exerts T-cell independent effects in skin. The Reynolds lab has previously shown that CypB is expressed and secreted by normal human epidermal keratinocytes (NHEK). In this work we aimed to investigate the functional role of CypB in the epidermis. Confocal analysis of normal human skin revealed CypB expression within the granular cell layer. Transduction of NHEK with retroviral vectors containing CypBWT-GFP, CypBW128A-GFP (a mutant reducing CsA binding by 97%) positively regulated keratinocyte differentiation (transglutaminase promoter luciferase and enzyme activity). In addition, transduction of NHEK with CypBWT and CypBW128A significantly increased colony formation and keratinocyte proliferation compared to empty vector. Furthermore, conditioned medium from NHEKs transduced with CypBWT or CypBW128A increased proliferation of naïve NHEK. Conversely, knockdown of CypBWT reduced NHEK proliferation. Moreover, NHEK transduced with CypBWT formed thicker epidermal equivalents compared with empty vector controls. Analysis of eczematous skin treated with CsA, showed changes in expression of CypB before and following 2 weeks of CsA treatment. An increase in filaggrin expression in eczematous skin during these early phases of treatment with CsA, suggests that CsA may act by positively repairing impaired barrier function. These studies provide an increased understanding of the physiological and pathological role of CypB in keratinocytes, further insight into the mechanism of action of CsA and may identify CypB as a novel drug target for atopic eczema.

Hidradenitis suppurativa (HS) is a chronic inflammatory dermatosis that presents with painful nodules, abscesses and sinus tracts in apocrine gland-bearing regions. Disease pathogenesis is poorly understood and there is a consequent paucity of effective treatment options. HS has been associated with smoking and obesity and can be inherited in an autosomal dominant (AD) manner. Heterozygous mutations in the gamma-secretase genes NCSTN, PSEN1 and PSENEN have recently been reported in some Chinese multiplex kindreds with HS. The overall aim of this programme of research was to understand the genetic architecture of HS, the ultimate goal being to clarify the molecular mechanisms involved in disease pathogenesis. The principle objectives were four-fold: 1/ Explore the involvement of mutations in NCSTN, PSEN1 and PSENEN in British familial cases of HS. 2/ Functionally characterise any identified mutations. 3/ Determine the contribution of mutations in NCSTN, PSEN1 and PSENEN in the general disease population. 4/ Analyse the clinical phenotype of individuals harbouring gamma-secretase gene mutations. Heterozygous gamma-secretase gene mutations were detected in affected individuals from two of seven British multiplex kindreds demonstrating AD inheritance. Mutations were detected in NCSTN (c.1125+1 G&gt;A) and PSENEN (c.66_67insG) which resulted in aberrant splicing (p.Glu333_Gln367del) and a frameshift (p.Phe23ValfsX98) respectively. Both mutant transcripts appeared unstable and subject to decay in primary human fibroblasts. A corresponding reduction in respective protein expression in mutant versus wild type fibroblasts implied that haploinsufficiency of the gamma-secretase components may underlie the development of HS in those cases. This apparent haploinsufficiency did not however affect gamma-secretase endopeptidase or carboxypeptidase activity in vitro. Forty eight individuals were sequentially recruited from a tertiary referral HS clinic and screened for variation in NCSTN, PSENEN and PSEN1. Three individuals harboured novel variants in NCSTN but no novel or rare (&lt;1% population frequency) variation was detected in PSEN1 or PSENEN. All three NCSTN variants were of uncertain pathogenicity. Mutations in the gamma-secretase genes NCSTN, PSENEN and PSEN1 would therefore appear to underlie up to 7% of British cases of HS. Phenotypic analysis of individuals with likely pathogenic gamma-secretase mutations revealed early onset, severe, widespread and treatment resistant disease often associated with atypical flexural pigmentation and prominent cystic changes in atypical areas. Given that gamma-secretase gene mutations only appear to underlie a small proportion of HS cases it was hypothesised that there is further genetic heterogeneity underlying HS. Unexplained familial cases and unrelated but carefully phenotyped and sub-grouped individuals were therefore assessed using a combination of traditional and next generation gene mapping techniques. No pathogenic mutations in additional genes were identified. The identification of gamma-secretase gene mutations in HS informs disease pathogenesis, potentially implicates the gamma-secretase-Notch signalling axis in disease development, provides a platform for ongoing functional studies and will hopefully facilitate the identification of new therapeutic targets in this debilitating disease. Ongoing genetic and functional investigation is now required to confirm the presence of further genetic heterogeneity and to establish the relevance of gamma-secretase-Notch signalling in the wider patient cohort.