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Biomedical subjects

A O'Driscoll

Publications and source records attributed to A O'Driscoll.

12 recordsLinked to original sources
PubMed1998

Acute intraoperative suprachoroidal haemorrhage in ocular surgery.

PURPOSE/BACKGROUND: Acute intraoperative suprachoroidal haemorrhage (AISH) is the most sight-threatening complication of ocular surgery. We investigated the visual outcomes following this intraoperative event, patient characteristics that may predispose to it and the clinical features that may be of prognostic significance. METHODS: The records of 45 cases of AISH collected from ophthalmic centres in the United Kingdom, Republic of Ireland and Switzerland were reviewed. Two satisfactory controls in terms of operative procedure, surgeon, age (+/- 5 years) and gender were found for each of 33 of our cases. Systemic and ocular characteristics were compared for cases and controls, and the visual results of all cases of AISH are analysed. RESULTS: Cases and controls differed only in terms of axial length and pre-operative intraocular pressure, both of which were significantly greater for eyes that experienced an AISH (p < 0.05). Ten eyes (22.2%) achieved a final Snellen acuity of 6/12 or better. Statistically significant associations with a final acuity of counting fingers or worse included spontaneous nuclear expression (p = 0.02), retinal detachment (p < 0.0001), four-quadrant suprachoroidal haemorrhage (p = 0.007) and vision of perception of light or worse at the first dressing (p = 0.0001). Four of the 6 eyes that experienced an AISH during phacoemulsification surgery had a visual outcome of 6/12 or better, and this was significantly greater than for cases involving extracapsular cataract surgery (p = 0.004). CONCLUSION: The results indicate that longer axial length and higher pre-operative intraocular pressure are associated with increased risk of AISH. Poor visual results are more likely following spontaneous nuclear expression, retinal detachment, four-quadrant suprachoroidal haemorrhage or vision of perception of light or worse at the first dressing. The results also suggest that AISH complicating a phacoemulsification procedure has a more favourable visual prognosis than AISH that occurs during extracapsular cataract surgery.

Acute Disease↗
PubMed1995

Low plasma heparin cofactor II levels in thalassaemia syndromes are corrected by chronic blood transfusion.

Low plasma heparin cofactor II (HCII) levels are associated with a thrombotic tendency, and we have previously shown these to be decreased in a variety of haemolytic conditions. The risk of thrombosis is recognized to be increased in both thalassaemia major (TM) and intermedia (TI), although the exact mechanisms are poorly understood. HCII levels have therefore been compared in 20 untransfused patients with TI and 20 regularly transfused TM patients to determine the influence of transfusion on HCII. Additionally, untransfused TI patients have been commenced on regular red cell transfusion and the effects on correction of low HCII levels investigated. HCII levels were significantly lower in the untransfused TI patients (mean 0.56 +/- 0.06 U/ml) compared to TM patients (mean 0.85 +/- 0.1 U/ml; P < 0.001). Levels in TI were significantly less than in healthy age-matched controls (P < 0.001) and correlated with Hb values (r = 0.8), whereas levels in TM were at the lower end of the normal range. ATIII values were within the normal reference range in both TI and TM, and HCII antigen showed a parallel reduction to HCII activity, indicating that reduction in HCII is not a consequence of increased thrombin consumption. Three patients with TI were commenced prospectively on hypertransfusion programmes which resulted in a slow normalization of their levels taking 2-3 months. These findings support a hypothesis that the low HCII levels are related to increased red cell turnover and can be normalized once this turnover has been suppressed by hypertransfusion. The thrombotic risk to patients with low HCII levels in the presence of haemolysis might in principle be decreased by such transfusion regimes.

Adolescent↗
PubMed1995

The metabolites of nitric oxide in sickle-cell disease.

Plasma NOx concentrations were raised in 22 acute painful crises in SCD. We have measured blood concentrations of nitric oxide metabolites (NOx) in sickle-cell disease (SCD), and shown that they are increased compared with healthy controls (P = 0.002), and haemoglobin E/beta-thalassaemic controls (P = 0.05). Concentrations in steady-state SCD were also higher than in healthy controls (P = 0.04) but not significantly different from the concentrations at the beginning of painful crises (P = 0.34). Importantly, in 12 regularly exchanged sicklers, the mean pre-transfusion NOx concentration did not differ significantly from the control population (P = 0.52), suggesting that the changes in NO metabolism can be reversed. It is unlikely that the increased concentrations of NOx in SCD result from anaemia or haemolysis as the untransfused haemoglobin E/beta-thalassaemics did not show increased levels.

Acute Disease↗
PubMed1994

Early AmBisome in febrile neutropenia in patients with haematological disorders.

Our previous experiences with liposomal amphotericin have suggested that it is an effective antifungal agent in neutropaenic patients with relatively few toxicity problems compared with conventional amphotericin B. This interim report presents early data from a single-centre, prospective randomised study with AmBisome. The study was designed to compare the early initiation of AmBisome in febrile neutropaenic patients (with haematological malignancy) with its later use, and to examine the efficacy and toxicity of different doses of this antifungal agent. Our experiences from the first 137 patients recruited (n = 200) are discussed, in addition to some of the difficulties that have arisen during the study.

Amphotericin B↗
PubMed1994

Factor VIIa and other haemostatic variables following bone marrow transplantation.

Hepatic venocclusive disease causes considerable morbidity and mortality following bone marrow transplantation. There are two hypotheses regarding the aetiology of this syndrome; firstly that changes in plasma coagulation factors and natural anticoagulants lead to a prothrombotic state and secondly that endothelial cell activation stimulates intravascular deposition of fibrin. We have investigated these mechanisms by measuring the changes in proteins C and S and factors VII and X in the post transplant period and by using the plasma concentration of factor VIIa as an in vivo marker of potential endothelial cell tissue factor expression. Protein C fell in both allograft and autograft patients but more so in the allografts. Similar results were found for factors VII and X. These changes were predominantly due to hepatic dysfunction induced by the chemo-radiotherapy. Factor VIIa levels were unchanged in both the allograft and autograft patients. We conclude that there is no convincing evidence for a procoagulant state following BMT as there are both anticoagulant and procoagulant changes. The absence of any changes in factor VIIa levels suggests that tissue factor was not exposed to the general circulation following BMT but does not exclude focal expression at the sites of thrombosis.

Bone Marrow Transplantation↗
PubMed1992

von Willebrand factor as a marker of endothelial cell activation following BMT.

Endothelial cell activation may play a role in thrombotic complications of BMT such as hepatic veno-occlusive disease (VOD), right atrial line thrombosis and microangiopathic haemolysis. To assess this, von Willebrand factor antigen (vWF:ag) was measured in 72 patients (25 allografts, 46 autografts and one syngeneic) during the first 6 weeks post-transplant. There was a significant rise in vWF:ag in both allografts and autografts but a greater increase was seen in the allografts. The changes in vWF:ag did not correlate with changes in C reactive protein showing that this was not merely an acute phase response. vWF multimers were normal in a subgroup of uncomplicated transplants showing that there was no large scale endothelial cell disruption. Patients with VOD did not have changes in vWF:ag that were consistently different from uncomplicated controls. Three of four patients who developed line thrombosis had higher levels of vWF:ag compared with control groups; multimeric structure of the vWF was again normal. These results show that there is endothelial cell activation post-BMT and that this is greater in allografts compared with autografts, thus suggesting a possible mechanism for the higher incidence of VOD in this group. There were no useful predictive markers of VOD or thrombosis in individual patients.

Adolescent↗
PubMedDate not supplied

Autologous stem cell transplantation in myeloma: the St James's Hospital experience, 1997-2003.

BACKGROUND: High-dose treatment with autologous stem cell transplantation (ASCT) has become the standard of care for patients with myeloma below the age of 65 years. AIMS: We report an audit of 60 patients (median age: 52.5 years) who underwent ASCT in the National Bone Marrow Transplant centre in St James's Hospital in Dublin between 1997 and 2003 inclusive. METHODS: Clinical and laboratory data were retrieved from patient medical records and hospital information management systems. RESULTS: Thirty-six patients had IgG, 11 IgA, 1 IgD, 9 light chain and 3 non-secretory MM. Fifty-seven (95%) patients received anthracycline-corticosteroid combination chemotherapy prior to autografting. There was no transplant-related mortality (TRM). Complete (CR) and Partial Responses (PR) were seen in 16 (29.6%) and 29 (53.7%) of those evaluable (n = 54 (90%)). The actuarial Progression-Free (PFS) and Overall Survival (OS) rates at five years are 13% and 55% respectively. CONCLUSION: Centre outcome is comparable to published international series and supports the use of ASCT in the treatment of this malignancy.

Aged↗