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Biomedical subjects

J G Pollock

Publications and source records attributed to J G Pollock.

At least 37 records · Page 2Linked to original sources
PubMed1991

A prospective study of 100 gelatin-sealed aortic grafts.

A gelatin-sealed knitted Dacron graft has been developed which has zero porosity at implantation and does not require preclotting. Its patency rate up to 57 months and effectiveness at saving blood loss have been studied. Gelatin-sealed aortic grafts were implanted into 100 consecutive patients--77 men, 23 women. Surgery was performed for aneurysm in 36 patients (including four with rupture), intermittent claudication in 44, rest pain in 17, and gangrene in three, over an 18 month period. The patients were followed up prospectively for 57 months. Perioperative mortality was 1%. Cumulative primary graft patency was 99%. There was no measurable blood loss at implantation. Forty-seven patients required blood transfusion: mean volume transfused was 430 ml. There were no problems related to the sealant.

Adult↗
PubMed1991

Early experience with intra-arterial thrombolytic therapy for peripheral arterial occlusion.

The authors present their early experience with local intra-arterial thrombolytic therapy for peripheral arterial occlusions causing limb threatening ischaemia, using streptokinase or urokinase. Ten patients were treated in a period of one year. Five patients had successful recanalisation, two patients had partial success and three patients required major amputation. The indications, contraindications and results of this treatment are reviewed.

Adult↗
PubMed1990

Infected false aneurysms in the groin of intravenous drug abusers.

The hazards of dealing with infected false femoral aneurysms resulting from intra-arterial narcotic injection are highlighted in six patients. Two patients were human immunodeficiency virus positive and three patients were hepatitis B surface antigen positive. Because of these infections exploration of groin swellings as presumed soft tissue abscesses is potentially hazardous without proper proximal vascular control. All patients underwent reconstruction following arterial ligation and five grafts became infected, with life threatening haemorrhage occurring in four patients. Five grafts have subsequently occluded or have been removed without loss of limb viability, although two patients have been regrafted. A high index of suspicion and assessment by a vascular surgeon, with angiography if indicated, is required in any intravenous drug abuser presenting with a groin swelling following injection. Because of the great risk of graft infection, it is suggested that ligation and debridement alone be carried out, with immediate arterial reconstruction only for non-viability.

Adult↗
PubMed1990

Long-term survival in patients undergoing resection of abdominal aortic aneurysm.

The long-term survival of patients undergoing abdominal aortic aneurysm surgery is presented. Three-hundred and thirty-eight patients who presented with elective, urgent, or emergency abdominal aortic aneurysms, have been followed retrospectively for five years. We found no statistical difference in the long-term survival in these three groups of patients. As expected patients who had successful operation survived better than patients who were not offered surgery because of their poor medical condition. Interestingly, advancing years, history of myocardial infarction or hypertension did not significantly influence long-term survival.

Adult↗
PubMed1990

Abdominal aortic aneurysm: a preventable cause of death?

Abdominal aortic aneurysm as a cause of death may be preventable by surgery. This paper reviews current theories of aetiology, incidence and detection with particular reference to population screening for aneurysm and to reducing the operative mortality rate by detecting the correctable risk factors of surgical treatment.

Aorta, Abdominal↗
PubMed1990

Management of congenital arteriovenous malformations.

Over a 6-year period, 12 patients with 14 congenital arteriovenous malformations were considered for a staged approach to include afferent vessel ligation (AVL) and/or intra-arterial embolization (IAE) and surgical excision where possible. Patients were followed for a period ranging from 3 to 60 months. Two patients had localized lesions which were completely excised. Five patients were treated by IAE followed by excision with a successful outcome in four. One patient had a transmetatarsal amputation for failed IAE. Two patients had both IAE and AVL before excision of the lesion. In one patient AVL alone was followed by a recurrence. Two patients with multiple lesions were kept under observation. It would appear that IAE and excision of an arteriovenous malformation can achieve cure or excellent palliation in most patients.

Adolescent↗
PubMed1990

Management of urgent intact abdominal aortic aneurysms.

Fifty patients with acute and urgent but unruptured abdominal aortic aneurysms were reviewed. The mortality rate was 24.3% in 37 patients having aneurysm resection and graft replacement. The mortality rate in patients developing cardiac and renal complications after surgery was 100%. Nine patients did not receive surgery and four patients had a laparotomy but did not have their aortic aneurysms repaired. Patients presenting with urgent but stable and unruptured abdominal aortic aneurysms require careful but swift assessment before surgery, and have a higher mortality than patients undergoing elective aneurysm surgery.

Aged↗
PubMed1989

Monoclonal antibody immunoassay in the study of thrombogenicity of preclotted and gelatin-impregnated aortic prostheses.

The Dimertest Enzyme Immunoassay has been used to compare the degree of thrombogenicity of the standard knitted Dacron prosthesis (n = 10) and the gelatin-impregnated Dacron prosthesis (n = 10) after infrarenal aortic reconstruction. After surgery there was a similar rise in cross-linked fibrin degradation products with both types of prostheses. Although on the third day the D-Dimer level in the gelatin-impregnated prosthesis was lower, there was no significant difference in the D-Dimer level at six weeks. This suggests that the potential risk of thrombogenicity in the gelatin-impregnated prosthesis is similar to the standard preclotted type.

Aged↗
PubMed1989

Associated carotid body tumour and pharyngeal pouch.

Paragangliomas are rare tumours which most commonly present as an asymptomatic neck mass. A small percentage of patients may have associated dysphagia. A 63-year-old male presented with a ten-month history of dysphagia. Physical examination revealed a pulsatile submandibular triangle neck mass. Computed tomography and angiography were diagnostic of a carotid body tumour. Barium swallow illustrated a hypopharyngeal pouch. He was treated by surgical excision of both lesions and cricopharyngeal myotomy. The simultaneous occurrence of both lesions has not been described before and highlights the need to find an alternative cause for dysphagia in patients with chemodectomas who fail to demonstrate oropharyngeal compression or lower cranial nerve palsies.

Carotid Body Tumor↗
PubMed1989

Atrial myxoma as the cause of acute lower limb ischaemia in a teenager.

We report a case of a previously well teenager presenting with a sudden cardiovascular collapse due to a saddle embolus. This required immediate surgical intervention. Histology of the embolic material showed it was myxomatous. Echocardiography confirmed the diagnosis and the patient made an uneventful recovery following excision of the right arterial myxoma.

Adolescent↗
PubMed1988

Effects of autologous mesothelial cell seeding on prostacyclin production within Dacron arterial prostheses.

Canine abdominal aortas have been replaced with Dacron arterial prostheses to assess the effects of mesothelial cell seeding on graft prostacyclin and thromboxane A2 release. At both 2 weeks and 6 weeks after surgery, three seeded and two unseeded control grafts were examined for prostacyclin release. In addition, thromboxane release was assessed in one seeded and one unseeded graft. Sections of aorta and graft were removed and incubated in PBS containing either 10 microM calcium ionophore A23187 or 20 microM arachidonic acid. The incubation mixture was sub-sampled at 5 min intervals over a 20 min period to assess the progressive release of prostacyclin and thromboxane A2 using a radioimmunoassay for 6-keto-prostaglandin F1 alpha and thromboxane B2 respectively. In seeded grafts, 6-keto-prostaglandin F1 alpha release averaged 15 per cent compared with aorta at 2 weeks and 45 per cent compared with aorta at 6 weeks. By contrast, release from unseeded grafts was undetectable at 2 weeks; however, by 6 weeks there was some release amounting to 15 per cent compared with aorta. There was a statistically significant increase in the release of 6-keto-prostaglandin F1 alpha from mesothelial cell seeded grafts at 6 weeks compared with unseeded grafts (P less than 0.01). Thromboxane release from the graft sections was variable and unrelated to whether the grafts had been seeded or not. These preliminary results, showing that grafts seeded with autologous peritoneal mesothelial cells release more prostacyclin than unseeded grafts, further highlight the role of the mesothelial cell as an alternative to the endothelial cell for improving the patency of arterial Dacron prostheses in the early postoperative days.

Animals↗
PubMed1988

Ruptured aortic aneurysms: postoperative complications and their management.

Postoperative complications in 92 patients undergoing repair of ruptured abdominal aortic aneurysms are reviewed. Renal failure and cardiac complications were fatal in 74% and 85% of the patients, respectively. Preoperative renal function at the time of presentation had no correlation with the development of renal failure. All but one patient in whom the left renal vein was divided developed renal failure postoperatively. There also was a preponderance of this complication in the patients needing suprarenal aortic control. Respiratory complications were seen in 29% of patients with 22% mortality. Peripheral emboli and ischemic colitis developed in 8% and 9% of the patients, respectively.

Aged↗
PubMed1988

Evaluation of factors influencing survival in ruptured aortic aneurysms.

During the six year period ending in December 1986, 103 patients with ruptured abdominal aneurysms presented to the unit. Ninety-two patients underwent surgery with a mortality of 39%. There was an increase in mortality with preoperative risk factors, extent of surgery, prolonged stay in ICU, complications and amount of blood transfused. However, only the latter was statistically significant. Age, the distance traveled by the patient before arrival at the hospital, systolic blood pressure on presentation and duration of operation did not affect the mortality.

Aorta, Abdominal↗
PubMed1988

Effects of venesection on leg blood flow in claudicants with high-normal haematocrit.

Patients with intermittent claudication frequently have high-normal levels of haematocrit and hence blood viscosity, which may contribute to decreased calf blood flow on exercise, and hence to the symptom of claudication. Reduction in haematocrit and viscosity by serial venesection in eight patients with stable claudication and high-normal haematocrit (mean 0.50) was performed, and the effects on claudication, calf blood flow, and calf oxygen delivery were studied. Following reduction in haematocrit to low-normal levels (mean 0.44), resting calf blood flow was unchanged; peak flow after ischaemic exercise increased slightly (+17%), but peak oxygen delivery (peak flow X haemoglobin concentration) was unchanged. Hence any increase in calf blood flow in the symptomatic leg is balanced by a decrease in oxygen-carrying capacity after venesection. No increase in claudication time would therefore be expected, and none was observed in the present study.

Adult↗
PubMed1988

Saddle embolus as first presentation of left atrial myxoma in a 14-year-old girl.

A 14-year-old girl was brought to the A & E department minutes after collapsing while out walking minutes earlier. She had developed sudden, severe, cramping pain in her lower abdomen and both legs, and had been incontinent of urine. Earlier that day she had an episode of diarrhoea. The girl was previously in excellent health.

Adolescent↗
PubMed1987

Experimental and clinical experience with a gelatin impregnated Dacron prosthesis.

Laboratory and clinical evaluation of a knitted Dacron graft impregnated with gelatin to confer zero porosity is described. Graft performance was tested by standard methods for biodegradation of the sealant and in vitro thrombogenicity. The gelatin sealant was removed after seven to nine days and there was no platelet adhesion to Gelseal compared with unsealed Dacron. Animal experiments revealed normal macroscopic appearances in the graft and histological disappearance of the gelatin impregnate between five and ten days, allowing a cellular response similar to unsealed Dacron. The first 100 patients to have Gelseal aortic bifurcation graft implanted at Glasgow Royal Infirmary are described. The graft did not require preclotting. Blood transfusion was not necessary in 74% of patients. There is 100% patency at 21 months. A knitted Dacron graft sealed with gelatin is a safe, nonporous prosthesis at implantation.

Acute-Phase Proteins↗
PubMed1987

Sealed versus unsealed knitted Dacron prostheses: a comparison of the acute phase protein response.

Twenty patients were randomized to receive either an untreated Dacron aortic bifurcation graft (n = 10), or a similar graft impregnated with gelatin (n = 10). Venous blood samples were taken preoperatively and at frequent intervals until five weeks after surgery. C-reactive protein (normal range less than 10 mg/l) and alpha l-acid glycoprotein (normal range 0.3-1.0 g/l) were measured. The peak mean value of C-reactive protein for the sealed group was 226.3 +/- 49.2 mg/l and 221.3 +/- 56.4 mg/l for the unsealed group. The corresponding values for alpha 1-acid glycoprotein were 1.49 +/- 0.25 g/l and 1.44 +/- 0.3 g/l. The C-reactive protein response returned more quickly to normal, with only two patients in each group having a slightly elevated response after four weeks, while the value for alpha l-acid glycoprotein remained elevated at five weeks for the same two patients in each group. There was no significant difference between the serum acute phase protein response in either group. This suggests that a knitted Dacron graft sealed with gelatin does not exaggerate the inflammatory response.

Acute-Phase Proteins↗