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Biomedical subjects

I G Rennie

Publications and source records attributed to I G Rennie.

At least 19 recordsLinked to original sources
PubMed2006

False diagnosis of papilloedema and idiopathic intracranial hypertension.

The diagnosis of idiopathic intracranial hypertension (IIH) relies heavily on the appearance of the optic disc. We report eighteen children referred to us over a 3 year period with disc swelling and suspected IIH. Following a tertiary ophthalmological review, papilloedema was excluded in ten with buried drusen, disc crowding, pseudopapilloedema, or misinterpretation of normal appearances. In these ten children, five had a mean opening pressure on lumbar puncture of 27.2 cm H2O, range 19-32, which was significantly lower than those with IIH (37.5 cm H2O, range 29-47; p<0.01). We conclude that diagnosis of IIH is difficult, and that more precisely defined criteria for assessment and diagnosis are needed.

Adolescent↗
PubMed2006

Bovine pericardium (Tutopatch) wrap for hydroxyapatite implants.

PURPOSE: To evaluate bovine pericardium (Tutopatch) as a wrapping material for hydroxyapatite implants in patients undergoing enucleation for uveal melanoma. METHOD: Prospective cohort study of patients who had enucleation for uveal melanoma between January 2003 and August 2003 were included in the study. Any patient with less than 3 months follow-up was excluded. Enucleation was performed under general anaesthesia followed by insertion of hydroxyapatite implants wrapped in bovine pericardium (Tutopatch). The recti muscles were sutured directly to the wrap. The tenon's capsule and conjunctiva were closed in two layers. A conformer was inserted at 1 week and artificial eye at 2-3 months. The patients were followed up regularly and were assessed for cosmetic result, exposure of implant, and the need for any further surgical procedures. RESULTS: A total of 19 patients (seven male and 12 female) were included in the study. Median age at diagnosis was 63 years (range 38-80 years). Median follow-up was 26 months (range 22-30 months). No patient developed postoperative complications of wound dehiscence. The overall cosmetic result was excellent in all the patients. The rate of postoperative complications compared favourably with published data using other wrapping materials/implants. CONCLUSION: Tutopatch is a safe wrapping material for hydroxyapatite orbital implants in patients undergoing enucleation for uveal melanoma.

Adult↗
PubMed2006

Multiple locations on chromosome 3 are the targets of specific deletions in uveal melanoma.

PURPOSE: Loss of chromosome 3 is a frequent event in uveal melanomas, which is associated with hepatic metastases and a poor prognosis. The entire copy of chromosome 3 is usually lost (monosomy 3); however, a small subset of tumours demonstrate partial deletions of chromosome 3. Analysis of these tumours may allow the identification of tumour suppressor genes (TSGs) that are the molecular target of monosomy 3. Therefore, the purpose of this investigation was to determine the location of these partial deletions of chromosome 3 in uveal melanomas. METHODS: Microsatellite analysis and restriction fragment-length polymorphism analysis were performed on 52 primary uveal melanomas using 19 markers located on both arms of chromosome 3. Cytogenetic analysis and fluorescence in situ hybridisation were performed, where possible, to confirm molecular findings. RESULTS: Of 52 tumours studied, five tumours (10%) demonstrated LOH at one or more informative markers, but retention of heterozygosity was observed at other loci on chromosome 3, consistent with the presence of structural abnormalities to chromosome 3. Consistent with previous findings, the pattern of LOH in these tumours indicates the presence of deletions around 3p25-26 and on 3q, and that a new target region at 3p11-14 is preferentially deleted. CONCLUSIONS: These results indicate the presence of several tumour suppressor loci on chromosome 3 and support the notion that the high rate of monosomy 3 in uveal melanoma is driven by disruption of several TSGs located on both arms of chromosome 3.

Chromosome Deletion↗
PubMed2005

Invasive and noninvasive uveal melanomas have different adhesive properties.

AIMS: To establish if invasive and noninvasive uveal melanomas have differences in expression of adhesion molecules, and whether their adhesive interactions with the extracellular matrix (ECM) and endothelium vary. METHODS: Cells from an invasive and noninvasive uveal melanoma cell line and hepatic and dermal microvascular endothelial cells were assessed by flow cytometry for adhesion molecule expression. Tumour cell adhesion to ECM substrates (collagens I and IV, fibronectin, laminin, and vitronectin) and endothelial cells was also investigated using a commercially available assay or a fluorescence-based in vitro assay, respectively. The significance of results comparing cell lines was determined using a Student's t-test, whereby P-values of less than 0.05 were taken as significant. RESULTS: alpha1- and alpha4-integrins were not expressed by noninvasive cells, but were detected on invasive cells. The invasive cell line also expressed higher levels of other integrins than the noninvasive line. Correspondingly, invasive cells adhered in higher numbers to ECM substrates and endothelial cells, and for the latter, the difference was highly significant (P<0.001). No preference in adhesion of invasive cells for the hepatic endothelium was observed. CONCLUSIONS: Successful attachment to and migration through the ECM, basement membrane, and endothelium are vital processes involved in malignant progression. Differential expression of alpha1- and alpha4-integrins by invasive and noninvasive cells infers a role for these receptors in invasion, while the ability of invasive cells to adhere more efficiently to the endothelium suggests that this is a critical factor in uveal melanoma invasion.

Cell Adhesion↗
PubMed2005

Ultrasound biomicroscopy in the management of melanocytoma of the ciliary body with extrascleral extension.

AIM: To demonstrate the ultrasound biomicroscopic features of a ciliary body melanocytoma with extrascleral extension, and a conservative approach in its management. METHOD: Observational case reports. Two cases of ciliary body melanocytoma were suspected at presentation, confirmed histologically by biopsy, and subsequently monitored for change by serial ultrasound biomicroscopic imaging. The main outcome measures were anatomical and functional preservation of the eye, with avoidance of formal surgical excision. RESULTS: Ultrasound biomicroscopy allows clear visualisation of the tumours, and the ultrasound characteristic is of low homogeneous internal reflectivity. 5 year follow up with observation only demonstrates success with this conservative management approach. Histopathological evaluation confirmed melanocytoma. CONCLUSIONS: Melanocytoma is a rare tumour. However if considered in the differential diagnosis at presentation and confirmed histologically, further management with use of the ultrasound biomicroscope as an accurate mode of imaging is an acceptable technique for preservation of the eye and avoids surgical excision.

Aged↗
PubMed2005

Regression of invasive conjunctival squamous carcinoma in an HIV-positive patient on antiretroviral therapy.

Case history of an African woman presenting with advanced HIV and a painful conjunctival lesion is presented. A conjunctival biopsy revealed invasive squamous cell carcinoma, with orbital invasion on computed tomography scan. She was commenced on antiretroviral therapy. She refused surgery to remove the eye and orbital contents (exenteration), and was referred to palliative care. Gradually, her immune status and ocular symptoms improved. At ophthalmic review, the tumour had apparently completely regressed. This unprecedented phenomenon may be due to antiretroviral therapy. Discussion covers conjunctival carcinoma and behaviour of HIV-related tumours with antiretroviral therapy. Antiretroviral drugs may offer a better alternative to disfiguring surgery in the future.

Adult↗