Biomedical subjects

T Irwin

Publications and source records attributed to T Irwin.

4 recordsLinked to original sources

PubMed2006

Epithelioid hemangioendothelioma mimicking a nerve sheath tumor clinically and on MR imaging.

Epithelioid hemangioendothelioma is a tumor of the soft tissues arising from the vascular endothelium. It is considered an intermediate grade malignancy. A 42-year-old female patient presented with pain and tingling down her right arm and a mass at the right medial upper extremity. MRI revealed an oblong mass along the course of the neurovascular bundle. Given the clinical and MR findings, a nerve sheath tumor was suspected. At surgery, the mass was adherent to both the brachial artery medially and the median nerve posteriorly. Pathology revealed epithelioid hemangioendothelioma. The imaging characteristics of epithelioid hemangioendothelioma on ultrasound, CT, and MRI are reviewed. Epithelioid hemangioendothelioma can mimic a nerve sheath tumor clinically and radiologically and should be considered in the differential diagnosis of tumors involving or adjacent to a neurovascular bundle.

Adult↗

PubMed1998

Role of p53 in the regulation of irradiation-induced apoptosis in neuroblastoma cells.

Wild-type p53 plays a crucial role in the control of apoptosis following ionizing radiation (IR); conversely, mutant p53 is associated with IR resistance. Although wild-type p53 is expressed in virtually all neuroblastoma tumors, treatment failures secondary to inadequate local control with radiotherapy are a problem in patients with advanced stage disease. This apparent paradox is the focus of our interest. The Shep-1 neuroblastoma cell line is highly resistant to IR. This cell line contains a wild-type p53 gene and is an ideal model for studying the mechanism of IR resistance in this disease. Following high-dose IR, cell fractionation demonstrated that p53 is induced and targeted to the nucleus. The induced p53 is functional as p53-responsive genes (Waf-1 and MDM-2) are appropriately induced following IR. Intriguingly, overexpression of p53 could reverse the inherent IR resistance of Shep-1 cells. Multiple cell lines expressing variable levels of exogenous temperature-sensitive p53 were generated. Pulse induction of p53 alone did not affect Shep-1 cell viability, while induction of p53, followed by IR, resulted in cell death and DNA fragmentation proportional to the dose of IR and the level of p53 expression. These findings demonstrate that p53 overexpression renders Shep-1 cells IR-sensitive and suggest that large quantities of exogenous p53 can overcome the factors inhibiting p53-mediated, IR-induced apoptosis.

Apoptosis↗

PubMed1998

Objective interpretation of bovine clinical biochemistry data: application of Bayes law to a database model.

With the advent of animal-side biochemistry analysers in veterinary practice, the requirement for ready access to reliable means for interpretation of the results is of increasing importance. At the University of Glasgow Veterinary School (GUVS), a large computerised hospital database containing extensive clinical, laboratory, and pathological information has been maintained. A retrospective study was undertaken to investigate plasma biochemistry results and corresponding post mortem diagnosis data from 754 unwell cattle which had presented to GUVS over the study period. Initial analysis of the clinical biochemistry data from this unwell population revealed that the parameters did not follow a normal distribution. This finding suggested that the accepted reference range method for the interpretation of clinical biochemistry data may provide limited information about the unwell animal. By applying a combination of percentile analysis and conditional probability techniques to the hospital data, the development of a means of clinical biochemistry interpretation was developed whereby a clinician could determine whether a value was abnormal, the degree of abnormality, and the most likely associated diseases. For example, a urea value of 30 mmol/l lay within the top 5% of results, and one of the most common diseases associated with this urea value was pyelonephritis. Furthermore, a Bayesian approach allowed the quantification of the relationship between any plasma biochemistry value and disease through the generation of a ratio termed the 'biochemical factor'. Using the same example, given a urea value of 30 mmol/l, pyelonephritis was eight times more likely than before any biochemistry information was known. The results from the study were used to form the basis of a software system which may ultimately be used by the clinical to aid in the recognition, treatment and prevention of disease in the veterinary domain.

Animals↗

PubMed1998

'Being there': learning through active participation.

Students engagement in learning is predicated not only on interest but on the perception of relevance to their needs. A hermeneutic interpretation of narrative student evaluation data from an introduction to nursing lecture course that was taught by means of a practice-based phenomenological approach revealed a pattern of student learning in which students moved from detachment to active participation in their learning. The stories shared by nurses in the practice setting were instrumental in introducing students to the world of nursing and facilitating a sense of belonging. Once engaged in the experience, students looked for opportunities to become active participants in their learning. A practice-based phenomenological approach to a theory course maximizes opportunities for student participation. Active reflection and integration allow students to make their own connections between theory and practice.

Curriculum↗