65 research outputs found
Adenoviral Vector Driven by a Minimal Rad51 Promoter Is Selective for p53-Deficient Tumor Cells
Background: The full length Rad51 promoter is highly active in cancer cells but not in normal cells. We therefore set out to assess whether we could confer this tumor-selectivity to an adenovirus vector. Methodology/Principal Findings: Expression of an adenovirally-vectored luciferase reporter gene from the Rad51 promoter was up to 50 fold higher in cancer cells than in normal cells. Further evaluations of a panel of truncated promoter mutants identified a 447 bp minimal core promoter element that retained the full tumor selectivity and transcriptional activity of the original promoter, in the context of an adenovirus vector. This core Rad51 promoter was highly active in cancer cells that lack functional p53, but less active in normal cells and in cancer cell lines with intact p53 function. Exogenous expression of p53 in a p53 null cell line strongly suppressed activity of the Rad51 core promoter, underscoring the selectivity of this promoter for p53-deficient cells. Follow-up experiments showed that the p53-dependent suppression of the Rad51 core promoter was mediated via an indirect, p300 coactivator dependent mechanism. Finally, transduction of target cells with an adenovirus vector encoding the thymidine kinase gene under transcriptional control of the Rad51 core promoter resulted in efficient killing of p53 defective cancer cells, but not of normal cells, upon addition of ganciclovir. Conclusions/Significance: Overall, these experiments demonstrated that a small core domain of the Rad51 promoter ca
The spine in Paget’s disease
Paget’s disease (PD) is a chronic metabolically active bone disease, characterized by a disturbance in bone modelling and remodelling due to an increase in osteoblastic and osteoclastic activity. The vertebra is the second most commonly affected site. This article reviews the various spinal pathomechanisms and osseous dynamics involved in producing the varied imaging appearances and their clinical relevance. Advanced imaging of osseous, articular and bone marrow manifestations of PD in all the vertebral components are presented. Pagetic changes often result in clinical symptoms including back pain, spinal stenosis and neural dysfunction. Various pathological complications due to PD involvement result in these clinical symptoms. Recognition of the imaging manifestations of spinal PD and the potential complications that cause the clinical symptoms enables accurate assessment of patients prior to appropriate management
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Within-host evolution of Staphylococcus aureus during asymptomatic carriage
Background
Staphylococcus aureus is a major cause of healthcare associated mortality, but like many important bacterial pathogens, it is a common constituent of the normal human body flora. Around a third of healthy adults are carriers. Recent evidence suggests that evolution of S. aureus during nasal carriage may be associated with progression to invasive disease. However, a more detailed understanding of within-host evolution under natural conditions is required to appreciate the evolutionary and mechanistic reasons why commensal bacteria such as S. aureus cause disease. Therefore we examined in detail the evolutionary dynamics of normal, asymptomatic carriage. Sequencing a total of 131 genomes across 13 singly colonized hosts using the Illumina platform, we investigated diversity, selection, population dynamics and transmission during the short-term evolution of S. aureus.
Principal Findings
We characterized the processes by which the raw material for evolution is generated: micro-mutation (point mutation and small insertions/deletions), macro-mutation (large insertions/deletions) and the loss or acquisition of mobile elements (plasmids and bacteriophages). Through an analysis of synonymous, non-synonymous and intergenic mutations we discovered a fitness landscape dominated by purifying selection, with rare examples of adaptive change in genes encoding surface-anchored proteins and an enterotoxin. We found evidence for dramatic, hundred-fold fluctuations in the size of the within-host population over time, which we related to the cycle of colonization and clearance. Using a newly-developed population genetics approach to detect recent transmission among hosts, we revealed evidence for recent transmission between some of our subjects, including a husband and wife both carrying populations of methicillin-resistant S. aureus (MRSA).
Significance
This investigation begins to paint a picture of the within-host evolution of an important bacterial pathogen during its prevailing natural state, asymptomatic carriage. These results also have wider significance as a benchmark for future systematic studies of evolution during invasive S. aureus disease
Childhood Headache Risk: Warning Signs and Symptoms Present During the First Six Months of Life*
Complex partial seizures and aphasia as initial manifestations of non-ketotic hyperglycemia: case report Crises parciais complexas e afasia como manifestações iniciais de hiperglicemia não cetótica: relato de caso
We describe a case of non-ketotic hyperglycemia (NKH), heralded by complex partial seizures and aphasia of epileptic origin, besides versive and partial motor seizures. This clinical picture was accompanied by left fronto-temporal spikes in the EEG. The seizures were controlled by carbamazepine only after the control of the diabetes. A month later, carbamazepine was discontinued. The patient remained without seizures, with normal language, using only glybenclamide. Complex partial seizures, opposed to simple partial seizures, are rarely described in association to NKH. Epileptic activity localized over language regions can manifest as aphasia.<br>Descrevemos um caso de hiperglicemia não-cetótica (HNC) cujas manifestações iniciais foram crises parciais complexas e afasia de origem epiléptica, além de crises versivas e parcias motoras. Este quadro clÃnico foi acompanhado por atividade epileptiforme na região fronto-temporal esquerda ao eletrencefalograma. As crises epilépticas foram controladas com carbamazepina (CBZ) apenas após o controle do diabetes mellitus. Após um mês, a CBZ foi suspensa, permanecendo a paciente com linguagem normal, sem novas crises epilépticas, em uso apenas de glibenclamida. Crises parciais complexas, ao contrário de crises parciais simples, são raramente descritas como manifestação de HNC. Atividade epileptiforme nas regiões relacionadas a linguagem podem manifestar-se como afasia
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