The Role of p53 in Human Epidermal Keratinocyte Terminal Maturation

Two cell lines, SCC12F and SCC12B were derived from the same squamous cell carcinoma of the facial epidermis and shown to display different phenotypes. SCC12B is more resistant to the induction of terminal differentiation and also more tumorigenic than SCC12F. The aim of this thesis was to investigate any genetic differences between SCC12B and SCC12F that could be responsible for their different phenotypes and therefore possibly be an important genetic event in the progression of squamous cell carcinomas of the head and neck (SCC-HN). Microsatellite analysis of SCC12B and SCC12F revealed no differences in loss of heterozygosity (LOH) at the loci investigated on chromosome 3p and 9 which have previously been reported to show frequent LOH in SCC-HN. No overexpression of cyclin D1 was observed in the two cell lines and others have reported the absence of any H-ras mutations or abnormalities in Rb-1. Analysis of the tumour suppressor gene p53 however revealed different levels of the protein between the two cell lines. SCC12B was shown to express much higher levels of p53 protein than SCC12F. Sequencing of p53 revealed a novel heterozygous mutation at codon 216, a T→G transversion substituting a valine for a glycine. Interestingly, whilst the mutant allele was visible in both cell lines SCC12B appeared to express much more mutant p53 than SCC12F which mostly retained wild-type p53 expression. Dot blot analysis suggested that mutant p53 expression in SCC12B was double that of SCC12F. Investigations were then undertaken to investigate whether the variations in this mutant to wild-type gene dosage could explain the different abilities of SCC12F and SCC12B to undergo suspension induced terminal differentiation. A clone of SCC12F, clone 19, expressing low levels of p53 and therefore presumably expressing a more normal phenotype was used as a target for alterations in mutant p53 expression. The use of this clone had the advantage that it retained a related genetic background to SCC12F and SCC12B and therefore is a more relevant target cell for investigating the effects of increased mutant p53216 on terminal differentiation. The results in this thesis show that increasing the mutant p53216 dosage in clone 19 decreased the cells ability to express involucrin and form cornified envelopes and increased cell survival in response to suspension induced terminal maturation. An increase in tumorigenicity was however not observed. Taken together these results therefore suggest that the acquisition of a p53 mutation is an early event in this SCC and its accumulation leads to a dramatic progression of this cancer. Inactivation of p53 appears to inhibit the cells ability to terminally differentiate and the possible roles of p53 in tumour progression are discussed

Vehicle telematics for safer, cleaner and more sustainable urban transport:a review

Urban transport contributes more than a quarter of the global greenhouse gas emissionns that drive climate change; it also produces significant air pollution emissions. Furthermore, vehicle collisions kill and seriously injure 1.35 and 60 million people worldwide, respectively, each year. This paper reviews how vehicle telematics can contribute towards safer, cleaner and more sustainable urban transport. Collection methods are reviewed with a focus on technical challenges, including data processing, storage and privacy concerns. We review how vehicle telematics can be used to estimate transport variables, such as traffic flow speed, driving characteristics, fuel consumption and exhaustive and non-exhaustive emissions. The roles of telematics in the development of intelligent transportation systems (ITSs), optimised routing services, safer road networks and fairer insurance premia estimation are highlighted. Finally, we outline the potential for telematics to facilitate new-to-market urban mobility technologies, signalised intersections, vehicle-to-vehicle (V2V) communication networks and other internet-of-things (IoT) and internet-of-vehicles (IoV) technologies

Measuring chlorine bleach in biology and medicine

Background: Chlorine bleach, or hypochlorous acid, is the most reactive two-electron oxidant produced in appreciable amounts in our bodies. Neutrophils are the main source of hypochlorous acid. These champions of the innate immune system use it to fight infection but also direct it against host tissue in inflammatory diseases. Neutrophils contain a rich supply of the enzyme myeloperoxidase. It uses hydrogen peroxide to convert chloride to hypochlorous acid. Scope of review: We give a critical appraisal of the best methods to measure production of hypochlorous acid by purified peroxidases and isolated neutrophils. Robust ways of detecting it inside neutrophil phagosomes where bacteria are killed are also discussed. Special attention is focused on reaction-based fluorescent probes but their visual charm is tempered by stressing their current limitations. Finally, the strengths and weaknesses of biomarker assays that capture the footprints of chlorine in various pathologies are evaluated. Major conclusions: Detection of hypochlorous acid by purified peroxidases and isolated neutrophils is best achieved by measuring accumulation of taurine chloramine. Formation of hypochlorous acid inside neutrophil phagosomes can be tracked using mass spectrometric analysis of 3-chlorotyrosine and methionine sulfoxide in bacterial proteins, or detection of chlorinated fluorescein on ingestible particles. Reaction-based fluorescent probes can also be used to monitor hypochlorous acid during phagocytosis. Specific biomarkers of its formation during inflammation include 3-chlorotyrosine, chlorinated products of plasmalogens, and glutathione sulfonamide. General significance: These methods should bring new insights into how chlorine bleach is produced by peroxidases, reacts within phagosomes to kill bacteria, and contributes to inflammation. This article is part of a Special Issue entitled Current methods to study reactive oxygen species - pros and cons and biophysics of membrane proteins. Guest Editor: Christine Winterbourn

The medical student

The Medical Student was published from 1888-1921 by the students of Boston University School of Medicine

A Case-Control Study of Hantavirus Pulmonary Syndrome during an Outbreak in the Southwestern United States

In May 1993, an outbreak of hantavirus pulmonary syndrome( HPS) occurred in the south-western United States. A case-control study determined risk factors for HPS. Seventeen case-patients were compared with 3 groups of controls: members of case-patient households( household controls), members of neighboring households( near controls), and members of randomly selected households ≥ 24 km away ( far controls). Investigators trapped more small rodents at case households than at near ( P = .03) or far control households( P = .02). After the number of small rodents was controlled for,case-patients were more likely than household controls to hand plow (odds ratio [OR], 12.3; 95% confidence interval [ CI], 1.1-143.0) or to clean feed storage areas (OR, 33.4; 95% CI, 1.7-666.0). Case-patients were more likely than near controls to plant( OR, 6.2; 95% CI, 1.1-34.0) and more likely than far controls to clean animal sheds( OR, 11.9;95% CI, 1.4-103.0). Peridomestic cleaning, agricultural activities, and an increased number of small rodents at the household were associated with HPS

A Case-Control Study of Hantavirus Pulmonary Syndrome during an Outbreak in the Southwestern United States

In May 1993, an outbreak of hantavirus pulmonary syndrome( HPS) occurred in the south-western United States. A case-control study determined risk factors for HPS. Seventeen case-patients were compared with 3 groups of controls: members of case-patient households( household controls), members of neighboring households( near controls), and members of randomly selected households ≥ 24 km away ( far controls). Investigators trapped more small rodents at case households than at near ( P = .03) or far control households( P = .02). After the number of small rodents was controlled for,case-patients were more likely than household controls to hand plow (odds ratio [OR], 12.3; 95% confidence interval [ CI], 1.1-143.0) or to clean feed storage areas (OR, 33.4; 95% CI, 1.7-666.0). Case-patients were more likely than near controls to plant( OR, 6.2; 95% CI, 1.1-34.0) and more likely than far controls to clean animal sheds( OR, 11.9;95% CI, 1.4-103.0). Peridomestic cleaning, agricultural activities, and an increased number of small rodents at the household were associated with HPS

On the interpretation of in situ HONO observations via photochemical steady state

A substantial body of recent literature has shown that boundary layer HONO levels are higher than can be explained by simple, established gas-phase chemistry, to an extent that implies that additional HONO sources represent a major, or the dominant, precursor to OH radicals in such environments. This conclusion may be reached by analysis of point observations of (for example) OH, NO and HONO, alongside photochemical parameters; however both NO and HONO have non-negligible atmospheric lifetimes, so these approaches may be problematic if substantial spatial heterogeneity exists. We report a new dataset of HONO, NOx and HOx observations recorded at an urban background location, which support the existence of additional HONO sources as determined elsewhere. We qualitatively evaluate the possible impacts of local heterogeneity using a series of idealised numerical model simulations, building upon the work of Lee et al. (J. Geophys. Res., 2013, DOI: 10.1002/2013JD020341). The simulations illustrate the time required for photostationary state approaches to yield accurate results following substantial perturbations in the HOx/NOx/NOy chemistry, and the scope for bias to an inferred HONO source from NOx and VOC emissions in either a positive or negative sense, depending upon the air mass age following emission. To assess the extent to which these impacts may be present in actual measurements, we present exploratory spatially resolved measurements of HONO and NOx abundance obtained using a mobile instrumented laboratory. Measurements of the spatial variability of HONO in urban, suburban and rural environments show pronounced changes in abundance are found in proximity to major roads within urban areas, indicating that photo-stationary steady state (PSS) analyses in such areas are likely to be problematic. The measurements also show areas of very homogeneous HONO and NOx abundance in rural, and some suburban, regions, where the PSS approach is likely to be valid. Implications for future exploration of HONO production mechanisms are discussed

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead