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Biomedical subjects

T V Keaveny

Publications and source records attributed to T V Keaveny.

At least 19 recordsLinked to original sources
PubMed2003

Objective measurement of breast cancer oestrogen receptor status through digital image analysis.

AIMS: The authors have previously described quantitative, computer-assisted analysis of oestrogen receptor status in immuno-histochemically stained sections in patients with primary breast cancer. The aim of this study was to validate the aforementioned system against the commonly used methods of assessing oestrogen receptor status. METHODS: Paraffin embedded sections from 156 patients with primary breast carcinoma were stained with anti-alpha-oestrogen receptor monoclonal antibody (1D5) using a standard immunohistochemical protocol. Images from 10 high-powered fields were captured from each section using a digital camera mounted on a microscope and analyzed using Adobe Photoshop image analysis software. A nuclear mask was obtained by digitally selecting the nuclear area. Staining intensity in the nuclear mask was then analyzed using red-scale absorption characteristics. Manual assessment of oestrogen receptor status was performed through counting the percentages of cells that are positive from 200 randomly sampled nuclei from ten high powered fields HPF. Cut off value for positivity was taken as 10%. Cytosolic oestrogen receptor concentration was measured through enzyme immunisation. Cut off value for ER positivity was taken as 200 fmol/g (wet tissue). RESULTS: One hundred and fifty-six sections were studied of which 41 were ER negative. Median percentage positivity in the remainder was 90% (17-100) by manual assessment. The median red scale value was 108 (58-156). A close correlation was observed between median optical density of the nuclear mask and percentage positivity assessed manually (P<0.0001). There was a significant correlation between the optical density of the nuclear mask and cytosolic oestrogen receptor concentration (P<0.001). CONCLUSION: Oestrogen receptor positivity can be accurately assessed through digital image analysis. This process offers objective data regarding the amount of oestrogen receptors within the nuclei as well as the percentage of nuclei, which express oestrogen receptors.

Adult↗
PubMed2001

Association between plaque instability, angiogenesis and symptomatic carotid occlusive disease.

BACKGROUND: Angiogenesis is a recognized feature of the atherosclerotic process and has been described in the context of unstable coronary atherosclerotic lesions. The aim of this study was to assess the association between angiogenesis in atherosclerotic carotid plaques and microscopic features of plaque instability, in particular intraplaque haemorrhage. METHODS: Consecutive patients undergoing carotid endarterectomy were included. Endarterectomy specimens were divided into their constituent atherosclerotic lesions. Histological sections were prepared and stained with haematoxylin and eosin, and immunohistochemically with an endothelial cell marker (CD34). The quantity of intraplaque haemorrhage was measured in transverse histological sections using computerized image analysis. Microvessel counts were performed in CD34-stained sections and were verified through computerized image analysis. RESULTS: Some 239 atherosclerotic lesions from 73 patients were available for analysis; 73 were early lesions, 74 were raised fibroatheromas and 92 were unstable atherosclerotic plaques. One hundred and fifty lesions were not haemorrhagic; 89 exhibited intraplaque haemorrhage, of which 28 involved less than 50 per cent of the plaque sectional area. There were higher microvessel counts in plaques containing over 50 per cent haemorrhage (P < 0.0001), unstable atherosclerotic lesions (P < 0.0001) and atherosclerotic lesions obtained from symptomatic patients (P < 0.001). CONCLUSION: There are strong associations between plaque vascularity, quantity of intraplaque haemorrhage and presence of symptomatic carotid occlusive disease.

Aged↗
PubMed1999

Pseudoaneurysm of the profunda femoris artery due to intertrochanteric fracture of the hip.

Arterial injury caused by hip fracture is a rare event. We report a case of pseudoaneurysm of the profunda femoris artery that presented 4 weeks after correction of an intertrochanteric hip fracture with a dynamic hip screw. The diagnosis was confirmed by Duplex ultrasound scanning, and it was treated by ligation of the profunda femoris artery at the level of the pseudoaneurysm.

Aged↗
PubMed1999

Inferior mesenteric venous sampling, pulse oximetry, and assessment of colonic perfusion during aortic aneurysm surgery.

Ischemic colitis is a serious complication of aortic surgery. The condition continues to be difficult to diagnose at an early stage. This study monitors the biochemical changes in systemic and selective inferior mesenteric vein (IMV) blood sampling during aortic surgery and compares the reproducibility of this method to intraoperative colonic pulse oximetry in a series of 18 patients undergoing infrarenal aortic aneurysm repair. Base excess, pH, pCO2, and lactate were altered by aortic cross-clamping but returned to normal within 48 hr. IMV inorganic phosphate levels were higher than systemic values, suggesting improved sensitivity with selective sampling. BB isoenzymes of creatine kinase remained normal in all patients. Pulse oximetry signals were inconsistently obtained from the colon. This study establishes the physiological changes in IMV biochemistry during aortic surgery. Unlike intraoperative pulse oximetry, selective IMV sampling provides reproducible measurements of colonic perfusion. This simple and safe technique warrants further assessment of its accuracy at diagnosing ischemic colitis.

Alanine Transaminase↗
PubMed1997

In vitro optimisation of a microdialysis system with potential for on-line monitoring of lactate and glucose in biological samples.

The optimisation and evaluation of the microdialysis component of a prototype miniaturised total analysis system for application in the continuous monitoring of lactate and glucose is reported. The complete unit comprises a high efficiency microdialysis sampling system, a miniaturised microflow manifold with an integrated biosensor array, together with the hardware and software necessary for controlling the flow parameters and monitoring the sensor signals. Sampling occurs via a microdialysis shunt probe which is perfused continuously with a physiological buffered saline solution. The continuous dialysate outflow is presented to the biosensor array, resulting in the appropriate amperometric signals. Aspects of technological significance addressed here include probe membrane size, perfusate flow rate, sample flow rate, temperature change, probe sterilisation procedures, and heparin content of the physiological saline solution employed.

Biosensing Techniques↗
PubMed1997

Novel instrumentation for real-time monitoring using miniaturized flow systems with integrated biosensors.

A prototype miniaturized Total Chemical Analysis System (muTAS) has been developed and applied to on-line monitoring of glucose and lactate in the core blood of anaesthetized dogs. The system consists of a highly efficient microdialysis sampling interface sited in a small-scale extracorporeal shunt circuit ('MiniShunt'), a silicon machined microflow manifold and integrated biosensor array for glucose and lactate detection with associated computer software for analytical process control. During in-vivo testing the device allowed real-time on-screen monitoring of glucose and lactate with system response times of less than 5 min, made possible by the small dead volume of the microflow system. On-line glucose and lactate measurements were made in the basal state as well as during intravenous infusion of glucose or lactate. The prototype muTAS is currently suitable for trend monitoring but refinements are necessary before application of the system for determination of individual lactate values.

Animals↗
PubMed1996

An intravascular microdialysis sampling system suitable for application in continuous biochemical monitoring of glucose and lactate.

Direct sensor implantation for continuous biochemical monitoring has proved disappointing, but microdialysis sampling devices can serve as a biocompatible patient-sensor interface. We propose a novel "MiniShunt" extracorporeal microdialysis sampling circuit designed to sample core blood, and report the performance of different microdialysis probe membrane types and sizes with pumped and non-pumped blood flow in anaesthetised dogs. Discrete microdialysate and plasma samples collected during glucose and lactate monitoring were analysed with a YSI analyzer and showed microdialysis efficiency (% relative recovery) in excess of 95% for both analytes using fibres of greater than 70 mm2 internal surface area. Pumped veno-venous extracorporeal blood microdialysis sampling of this type could provide a suitable interface for future multi-analyte on-line biosensor applications in critically ill patients.

Animals↗
PubMed1994

Investigation and management of subclavian steal syndrome.

Patients with subclavian steal syndrome present with symptoms of vertebrobasilar ischaemia. Although angiography has traditionally been used to confirm the diagnosis of subclavian steal and plan reconstructive surgery in symptomatic patients, duplex ultrasonography now offers rapid diagnosis and also permits examination of the other extracranial vessels. The treatment of subclavian steal syndrome is surgical. Extra-anatomic bypass procedures are used to increase inflow to the subclavian artery, abolishing the steal phenomenon. Carotid-subclavian bypass or transposition and subclavian-subclavian or axilloaxillary bypass are the procedures of choice; selection is governed by the presence of coexistent carotid artery disease. Percutaneous transluminal balloon angioplasty of the subclavian artery is an alternative treatment, although the long-term patency rate is inferior to that of extra-anatomic bypass.

Carotid Arteries↗
PubMed1990

Carotid body tumours: report of six cases and a review of management.

We have treated six patients with carotid body tumours in the period from 1972 to 1988. All patients had a neck mass on presentation. In addition one patient complained of tinnitus and another was noted to have Horner's syndrome. The diagnosis was confirmed by ultrasound and angiography in all cases. Five patients subsequently underwent successful surgical resection. At the time of surgery one of the tumours was found to be locally invasive. One elderly patient was deemed unfit for surgery and was managed non-surgically with a satisfactory outcome. A review of the literature reveals that surgery is still the preferred mode of treatment although preoperative embolization may be a useful adjunct. Although the incidence of peroperative stroke has gradually been reduced from that found in earlier series, injury to the cranial nerves remains high and is the main hazard of surgical management. The improved results of surgical resection in more recent reports support the view that these tumours should be treated in units with expertise in vascular surgery of the neck.

Adult↗
PubMed1988

Cell shock.

Explore the source record for details and available documents.

Humans↗
PubMed1986

Contribution of nuclear medicine to vascular surgery.

Radioisotopes have been used for many years in the diagnosis of vascular abnormalities. In some areas the technique is regarded as routine and essential, while in others its place is less certain. This is often the case because of competition from other diagnostic methods or the facility may not be readily available. With the active participation of the Department of Nuclear Medicine, radionuclides can be used to provide information in both clinical diagnosis and laboratory investigation. It is intended to emphasise those areas where the method appears to have a rewarding clinical application.

Aneurysm↗