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Biomedical subjects

A Holden

Publications and source records attributed to A Holden.

At least 19 recordsLinked to original sources
PubMed2006

Renal artery stent revascularization with embolic protection in patients with ischemic nephropathy.

A prospective analysis of renal artery stent revascularization with distal embolic protection in a high-risk patient population with ischemic nephropathy is presented. A total of 63 patients (median age 70.2 years, range 54-86 years) had significant atherosclerotic stenosis of 83 renal arteries documented on pre-procedural imaging. All patients had baseline chronic renal insufficiency with a documented deterioration in renal function in the 6 months before revascularization. The endovascular technique used in all patients involved primary passage of an embolic filter into the distal main renal artery followed by primary stent deployment with a balloon expandable stainless steel stent. The filter baskets were recaptured and contents submitted for pathological analysis. At 6 months post-intervention, 97% of patients demonstrated stabilization or improvement in renal function. Only 3% of patients had an inexorable decline in renal function, unchanged by the intervention. After a mean follow up of 16.0 months (6-27), 94% of patients demonstrated stabilization or improvement in renal function. One patient suffered an acute post-procedural deterioration in renal function. In total, 60% of the filter baskets contained embolic material. This study confirms the technical feasibility of renal artery stent deployment with adjuvant embolic protection. The excellent results for renal preservation at 6 months post-intervention also suggest that a distal embolic protection device may improve the impact of percutaneous renal revascularization on progressive deterioration in renal function. The postulated mechanism is through the prevention of atheromatous embolization and the embolic yield from the distal filters supports this hypothesis. Patients most likely to receive the greatest benefit are those with mild baseline chronic renal insufficiency and a recent decline in renal function.

Aged↗
PubMed2006

Basal ganglia activation in Parkinson's disease.

The objective of this study was to compare basal ganglia activation in patients with Parkinson's disease to that of healthy controls, using functional MRI (fMRI). Six mildly-affected patients, off antiparkinsonian medications for at least 12h, and seven age-matched controls performed a unilateral motor switching task during fMRI data acquisition. Clear differences in basal ganglia activation were seen, with control subjects showing greater activation during both the left and right movement sessions. We observed activation of right sided basal ganglia structures in both groups, particularly with right sided movements, with caudate activation noted most frequently. This observation is consistent with right caudate involvement in the learning of new tasks and in association with externally paced movements.

Adult↗
PubMed2006

Spontaneous coeliac artery dissection.

A patient with spontaneous coeliac artery dissection that presented as upper abdominal pain is reported. This was diagnosed on contrast-enhanced multislice helical CT. The patient was treated conservatively and follow-up CT showed mild aneurysmal change of the splenic artery and a small splenic infarct. Isolated dissection of the visceral arteries (and, in particular, the coeliac artery) is extremely rare. With such limited evidence, decisions over best management are difficult, but depend on initial severity and progression at follow up.

Aortic Dissection↗
PubMed2002

Studies on the putative interactions between the organophosphorus insecticide Phosmet and recombinant mouse PrP and its implication in the BSE epidemic.

It has been suggested that exposure of cattle to the ectoparasiticide Phosmet in the 1980s caused a conformational change in the cellular prion protein (PrP(C)) to form the BSE prion (PrP(SC)), which initiated the epidemic of bovine spongiform encephalopathy (BSE). Recombinant mouse cellular prion (r[mouse]PrP(C)) was exposed to the organophosphorus pesticide Phosmet in vitro and the conformation of the prion before and after exposure was monitored using circular dichroism (CD) spectroscopy, utilizing synchrotron radiation at the Council for the Central Laboratory of the Research Councils (CLRC) facilities at Daresbury, UK. Metabolites of Phosmet, generated in situ by rat microsomes, were investigated in the same way, to determine whether they might initiate the conformational change due to their high chemical reactivity. Our studies showed that exposure of r[mouse]PrP(C) to Phosmet or microsomes-generated metabolites of Phosmet did not result in the conformational change in the protein from alpha-helix to beta-pleated sheet that is characteristic of the PrP(C) to PrP(SC) conversion and, therefore, Phosmet is very unlikely to have initiated the BSE epidemic by a simple direct mechanism of conformational change in the prion protein.

Animals↗
PubMed2001

Inflammatory pseudotumour of the liver.

A case of inflammatory pseudotumour of the liver is presented. The clinical, radiological and pathological findings are described and a brief discussion of this rare but important condition is presented.

Biopsy↗
PubMed2000

Pelvic fracture pattern predicts pelvic arterial haemorrhage.

BACKGROUND: The association between pelvic fracture pattern and the need for pelvic arterial embolization remains controversial. To address this issue, a study of the experience at Auckland Hospital was undertaken. METHODS: Review was undertaken of a trauma database, blood bank database, patient records and pelvic radiographs. Of the 364 pelvic fracture patients admitted over a 4-year period, 76 were transfused with 6 or more units of blood in the first 24 h and these constitute the study population. RESULTS: Embolized patients were older (median age 42 vs 29.5 years; P < 0.05) and had a higher abbreviated injury score for the pelvic girdle (median 3 vs 2; P < 0.05) compared to non-embolized patients. Revised trauma score (median 7.69 vs 7.55), injury severity score (median 29 vs 30.5), morbidity (55 vs 39%) and mortality (45 vs 32.1%) rates did not differ significantly between embolized and non-embolized groups, respectively. The median blood transfusion requirement in the first 6 h from injury was 14 units in embolized and 8 units in non-embolized patients (P = 0.005). Embolization was required in 12 of 27 (44.4%) patients with fracture patterns indicative of major pelvic ligament disruption, whereas seven of 38 (18.4%) patients without these fracture patterns required embolization (P < 0.05). CONCLUSIONS: The need for pelvic embolization correlated with fracture patterns that indicated major ligament disruption, although the relationship was not sufficiently strong to warrant change to current indications for pelvic angiography.

Adolescent↗
PubMed2000

Therapeutic embolization for acute haemorrhage in the abdomen and pelvis.

Therapeutic embolization for acute haemorrhage is increasingly being utilized. An audit of 34 patients undergoing therapeutic embolization for acute abdominal or pelvic haemorrhage was undertaken, in an attempt to assess the importance of the following variables in determining a successful outcome: coagulation status, transfusion status, time to procedure after onset of circulatory instability, duration of procedure, and the effect of the embolization technique employed. Overall success was 79%, with definitive control of haemorrhage achieved by embolization; 21% required surgical management for rebleeding 4-24 h post embolization. The duration of the procedure and transfusion status of the patient were the most important factors associated with a successful outcome.

Abdomen↗
PubMed2000

The value of narrow CT window settings in the recognition of subtle acute aortic intramural haematoma.

Four patients with acute aortic intramural haematoma are presented. In all patients the typical crescentic hyperdense rim within the aortic wall was not obvious on unenhanced CT when reviewed on standard mediastinal windows, but the hyperdense crescentic rim was well seen on narrow window settings. The findings suggest that all patients with a typical clinical presentation of acute thoracic aortic dissection who do not have a classical dissection on contrast-enhanced CT or a hyperdense intramural haematoma on standard mediastinal settings, should have the non-contrast scans reviewed on narrow window settings.

Aortic Dissection↗
PubMed2000

Value of a contrast agent in equivocal carotid ultrasound studies: pictorial essay.

The aim of the present study was to assess the use of an echo-enhancing agent (Levovist; Schering AG) in equivocal carotid bifurcation ultrasound studies and compare the information obtained with digital subtraction angiography (DSA). Contrast-enhanced carotid ultrasound studies were performed on 30 carotid bifurcations in 28 patients. The standard carotid ultrasound examinations were considered equivocal for two reasons: apparent acute internal carotid artery occlusions (n = 10), and possibly patent but critically stenosed internal carotid arteries with the residual flow lumen being incompletely visualized (n = 20). All patients underwent subsequent carotid digital subtraction angiography. All patients with apparent acute carotid occlusions (n = 10) were correctly characterized on contrast-enhanced ultrasound when compared with DSA. The majority were complete occlusions (n = 8) although in two cases there were critical carotid stenoses requiring surgical endarterectomy. In the 'incompletely visualized lumen' group (n = 20), the majority (n = 16) were correctly characterized on contrast enhanced ultrasound: 13 cases of critically stenotic but patent internal carotid arteries, two cases without a haemodynamically significant stenosis and one case of a carotid occlusion with patent vasa vasorum. One of the critical carotid stenoses was prospectively reported as occluded on the 'gold standard' angiography. In three cases the flow lumen was still incompletely visualized due to calcified plaque despite an echo-enhancing agent; angiography revealed no significant stenosis in all cases. There was one false negative for internal carotid occlusion. This occurred early in the series and could be considered to be a technical error. Importantly, there were no false positives for carotid occlusion. Contrast-enhanced carotid ultrasound significantly improves diagnostic confidence in equivocal carotid ultrasound studies. In appropriate clinical settings this may reduce the need for subsequent carotid angiography.

Acute Disease↗
PubMed1999

Measuring the impact of Parkinson's disease with the Parkinson's Disease Quality of Life questionnaire.

OBJECTIVES: To assess the validity of the Parkinson's Disease Quality of Life (PDQL) questionnaire, a patient-specific multi-dimensional quality of life measure, in a community-based sample of patients with Parkinson's disease (PI)) using standardized measures of disease severity, depressive symptomatology and cognitive function. DESIGN: A group of 194 patients with probable PD were randomly selected from a community-based register and were invited to self-complete the 37-item PDQL. Disease severity was measured by the disease-specific Webster scale, cognition by the CAMCOG neuropsychological test and depressive symptomatology by the self-report 15-item GDS-15 geriatric depression scale. RESULTS: A total of 136 patients returned completed PDQL questionnaires. Significant differences (P < 0.05) emerged between the pooled PDQL score of patients grouped on the basis of disease severity. Depressive symptoms and cognition were also associated with poorer perceived quality of life as measured by the PDQL. CONCLUSIONS: The results of this study are indicative of the validity of the PDQL as an important additional measurement which reflects the impact of PD from the patient perspective. It shows poorer quality of life to be associated with increasing age, disease severity more severe depressive symptomatology and impaired cognitive functioning. However, the responsiveness of this instrument in the evaluation of care in PD remains to be determined.

Aged↗
PubMed1998

Spontaneous arterial thrombosis in association with pancreatic carcinoma: diagnosis and interventional management.

A 58-year-old woman presented with bilateral upper limb ischaemia. Digital subtraction angiography demonstrated upper limb arterial thrombosis, extensive on the left. This was initially treated with catheter-directed thrombolysis which cleared the thrombus on the right, although the left upper limb required supplementary surgical embolectomy. Subsequently, biopsy-proven pancreatic adenocarcinoma was detected. The upper limb arterial thrombosis appeared to be spontaneous in association with the malignancy because there was no obvious embolic source.

Adenocarcinoma↗
PubMed1998

Thoracic chordoma mimicking a neurogenic tumour.

A case of chordoma arising in the thoracic spine of a 20-year-old man is presented. Plain film and magnetic resonance imaging findings are included. The case is unusual in that the neoplasm presented as dumb-bell-shaped extradural mass, traversing and expanding a thoracic neural foramen and thereby mimicking a neurogenic tumour.

Adult↗
PubMed1996

The Perth endoluminal bifurcated graft system--development and early experience.

The study aim was to develop a reliable endoluminal graft system that would enable the deployment of a bifurcated graft for infrarenal abdominal aortic aneurysms. A life-size plastic model was made of an abdominal aorta and iliac arteries, with a 50-mm infrarenal abdominal aortic aneurysm. This model was used to develop and test self-expanding graft systems, based on a barbed Gianturco stent and series of stainless-steel 'Z' stents within a woven Dacron graft. The bifurcated system developed involves a trouser graft with one long leg and one short. This graft-system is delivered through one femoral artery with deployment of the proximal aortic end infrarenally and the longer trouser leg within the ipsilateral common iliac artery. The short trouser leg is left hanging free within the distal end of the aneurysm cavity, just above the bifurcation. It is held open by a self-expanding stent and is cannulated from the contralateral femoral artery with a guide wire. A simple straight self-expanding stented graft is then deployed to extend this short trouser leg down into the common iliac artery, effectively creating an extension to the short leg. The graft system has been deployed in 21 patients with satisfactory exclusion of the aneurysm in 17 (81%). There has been one mortality and no conversion to open repair. All 17 aneurysms remain excluded at median follow-up of 30 (range 4-60) weeks. None of the four graft stents that leaked (two proximal and two distal) sealed spontaneously. Deployment of the uncovered Gianturco stent across the renal artery origins in 18 cases (85%) has not been associated with renal artery occlusion or deterioration in renal function at a median follow-up of 30 (range 4-60) weeks. The ability to deploy a bifurcated system increases the potential for endoluminal treatment of abdominal aortic aneurysm.

Aged↗
PubMed1996

Pre-operative staging of gastro-oesophageal junction carcinoma: comparison of endoscopic ultrasound and computed tomography.

Fifteen patients with carcinoma of the gastro-oesophageal junction were pre-operatively staged with endoscopic ultrasound (EUS) and computed tomography (CT). The accuracy of tumour and nodal staging using both modalities was compared to the final histological staging of the resected specimens. In staging depth of tumour growth, EUS was significantly more accurate (87% of lesions correctly staged) than CT (40% correctly staged). In staging nodal involvement, EUS was again significantly more accurate (73% correctly staged) than CT (33%). Two-thirds of the lesions were traversable with the endoscopic probe, but most of the nontraversed lesions were correctly staged on EUS. In this study, CT has performed poorly as a staging modality for carcinoma at the gastro-oesophageal junction. Other studies have shown CT to be less accurate at this location than at other oesophageal sites. The orientation of the gastro-oesophageal junction, lack of surrounding fat planes, proximity of adjacent organs and patient motion contribute to the poor staging performance of CT at this location. In contrast, EUS has been an accurate staging modality at the gastro-oesophageal junction in this study and compares well with other studies evaluating EUS in the more proximal oesophagus. Endoscopic ultrasound is therefore a necessary modality if accurate pre-operative staging of gastro-oesophageal junction carcinoma is to be achieved.

Adenocarcinoma↗
PubMed1996

Breast MRI: early experience with a 3-D fat-suppressed gradient echo sequence in the evaluation of breast lesions.

The early clinical experience with a 3-Dimensional Fourier Transform Gradient Echo sequence with fat suppression in the evaluation of breast masses is reported. Ten female patients with breast malignancies were pre-operatively evaluated with this sequence and the results compared with the pathological specimens. The scanning protocol included a non-contrast sequence followed by an immediate post-contrast sequence (completed 4.5 min after intravenous contrast injection) and a delayed sequence. Images were assessed for maximum lesion and parenchymal enhancement, lesion size and additional enhancing abnormalities. In six patients, malignant masses enhanced maximally on the immediate post-contrast sequence with parenchyma enhancing maximally on delayed images. In three cases, there was preferential enhancement of malignant lesions over normal parenchyma but to a similar degree on both post-contrast sequences. In one case, both the lesion and parenchyma enhanced maximally on the delayed sequence. Magnetic resonance assessed lesion size accurately and also detected satellite malignancies in one case. However, lesion grade, associated in situ carcinoma and lymphovascular invasion did not impact on lesion enhancement. In this small series, a contrast-enhanced, fat-suppressed 3-D Gradient Echo Sequence detected breast carcinoma with high sensitivity. The technique holds promise but further evaluation is required.

Breast↗
PubMed1996

Intramural aortic dissection.

We present 10 cases of intramural aortic dissection. The cases are all characterized by the presence of intramural haematoma without the presence of a patent false lumen. The radiological features and possible aetiologies are discussed. The key radiological finding is the presence of a hyperdense rim in the aortic wall on a non-contrast-enhanced computed tomography (CT) scan. In one case, a delayed diagnosis was made using magnetic resonance imaging (MRI). In a further case, the delayed development of a large aortic ulcer was demonstrated. Intramural aortic dissection has only recently been described in the radiological literature. The aetiology of this condition remains controversial. The imaging findings may be subtle and the diagnosis is still frequently being overlooked. We believe CT to be the primary diagnostic test for this condition, and its advantages over MRI and transoesophageal echocardiography (TOE) are discussed.

Aged↗