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Biomedical subjects

F Ashton

Publications and source records attributed to F Ashton.

At least 37 records · Page 2Linked to original sources
PubMed1985

Atherosclerosis in vascular grafts for peripheral vascular disease. Part 1. Autogenous vein grafts.

29 autogenous vein grafts, from 26 patients with peripheral arterial disease, were studied. 4 grafts of Group I (less than 3 months duration) were patent and removed for reasons other than graft failure. These showed 'arterialisation' only; 4 grafts of Group II (duration 5-18 months) showed thrombotic occlusion; 21 grafts of Group III (duration greater than 2 years) showed impaired graft patency and lipid identifiable as apolipoprotein B-containing-lipoproteins (LpB), and fibrinogen-related antigens (FRA) were seen as intramural deposits in the thickened grafts. LpB was also seen in a perifibrous distribution on the collagen of organised thrombi. Complicated lesions in some Group III grafts showed stenosis or occlusion, ulceration, calcification or aneurysm formation. These features suggest that a process indistinguishable from 'true' atherosclerosis affects vein grafts of long duration. The ways in which such changes may: contribute to graft failure; and improve our understanding of the basic processes involved in atherogenesis, are discussed.

Adult↗
PubMed1985

Protection against infection with Neisseria meningitidis group B serotype 2b by passive immunization with serotype-specific monoclonal antibody.

Hybridomas derived from mice immunized with Neisseria meningitidis serogroup B serotype 2b (B,2b) outer membrane preparations produced monoclonal antibodies (MAbs) specific for major outer membrane proteins of classes 1, 2, and 5. The MAbs were examined by enzyme-linked immunosorbent assay against a selected panel of seven strains of N. meningitidis (B,2b) of different sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns, a serotype 2a, and a nontypable strain. The five MAbs selected were all bactericidal and of different immunoglobulin subclasses. None of the MAbs reacted with other bacterial strains in a dot-enzyme immunoassay. The corresponding antigenic determinant for each MAb was localized on a specific outer membrane protein by immunoblotting of sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns of major outer membrane proteins. MAbs M5-11 and M5-30 bound to the class 2 protein and were serotype 2b specific. MAb M2-20 bound to the class 1 protein, and MAbs M5-16 and M5-19 bound to the class 5 protein. A mouse model of infection was established whereby a local infection progressed to lethal bacteremia over 3 days, and 50% of the animals were killed with an intraperitoneal injection of 10 meningococci plus 4% mucin and 1.6% hemoglobin. The ability of the MAbs to provide passive protection against experimental infection with N. meningitidis (B,2b) was examined. Both serotype-specific MAbs M5-11 and M5-30 were highly protective even though they were of different immunoglobulin subclasses. The class 5-specific MAb offered no protection, while the class 1-specific MAb gave limited protection. It may therefore be possible to provide protection against serotype 2b infection by using as vaccine the class 2 serotype-specific surface-exposed outer membrane protein epitopes defined by MAb M5-11 or M5-30.

Animals↗
PubMed1985

Problems in diagnosis of popliteal aneurysms.

Clinical features and errors in diagnosis have been assessed in a retrospective study of 62 popliteal aneurysms in 40 patients, 22 of whom had bilateral aneurysms. Only 29% of patients complained of pain or swelling behind the knee, while 31% of aneurysms had produced distal ischaemia presenting as intermittent claudication, 9 aneurysms had thrombosed producing ischaemic rest pain in 6 legs, and 4 aneurysms had ruptured. Although 94% of aneurysms were suspected or confidently diagnosed by palpation alone, only 43% of patients had had the correct diagnosis made at the time of initial referral. Treatment was delayed in 12 patients, 8 of whom subsequently required amputation. Popliteal aneurysm should be suspected in patients with a prominent popliteal pulse who present with intermittent claudication, and in patients with acute ischaemia of the leg who may have a thrombosed aneurysm requiring surgical exploration.

Adult↗
PubMed1984

Ruptured aortic aneurysms: postoperative complications and their aetiology.

A review of 198 ruptured aortic aneurysms has been undertaken, this being 36.3 per cent of all the aneurysms treated during the period 1960-81. The overall mortality rate was 42.9 per cent. The peroperative mortality was 6.6 per cent and the mortality of the patients who survived the operation was 38.9 per cent. Factors which influenced postoperative mortality were the age of the patient, the distance travelled to hospital, the presence of an intraperitoneal bleed, the duration of the operative procedure and the volume of blood transfused, but only the amount of blood transfused had a statistically significant influence on mortality. However, as the highest mortality associated with any of these risk factors was 54.9 per cent, no single factor alone can be considered a contra-indication to operation. As there are no reliable predictive factors, we believe that all cases with clinically ruptured aortic aneurysms should have a laparotomy and resection. The most common postoperative complications were varying degrees of renal and respiratory insufficiency and the occurrence of these was significantly associated with the volume of blood transfused.

Acute Kidney Injury↗
PubMed1984

Acute gastrointestinal complications of infrarenal aortic aneurysm repair.

Acute gastrointestinal complications developed in 31 of 472 patients following aortic aneurysmectomy (6.6 per cent). In order of frequency these were: ischaemic intestine in nine patients, mechanical or paralytic ileus in eight patients, peptic ulceration in seven patients, undiagnosed gastrointestinal bleeding in five patients and paraprosthetic fistula in two patients. The risk of developing peptic ulcer complications was not significantly increased in patients with a previous history of peptic ulcer disease. The risk of developing an ischaemic intestine was increased if the distal limb of a prosthesis was anastomosed directly to the external iliac artery. The associated mortality was high and 21 (67.7 per cent) patients died. 33.3 per cent of the mortality occurring with elective aneurysm resection was associated with gastrointestinal complications.

Acute Disease↗
PubMed1981

Diagnosis and management of 528 abdominal aortic aneurysms.

Between 1960 and 1979 528 patients with abdominal aortic aneurysms presented to the university department of surgery. Of these, 222 (42%) were elective cases, 72 acute (14%), 174 had ruptured (33%), and four had had a spontaneous aortoduodenal fistula (1%). In all these patients resections were undertaken, but in another 56 patients (11%) the aneurysm was not resected. A review of these cases showed that 91% had symptoms at their first presentation; abdominal pain and backache being most common. The diagnosis could be established in 91% by the presence of pulsatile abdominal mass on clinical examination. The operative mortality for elective resection was 8%, for acute 19%, for ruptured cases 42%, and for spontaneous aortoduodenal fistula 50%. After successful resection the overall five-year survival was 65% by the life table method, and there was no significant difference between elective, acute, and ruptured cases. This five-year survival after resection compares favourably with the expected 76% survival of a similar normal population, and was considerably better than that for conservatively treated patients. As most cases have symptoms, and diagnosis may be established easily by routine physical examination in 91%, the prognosis for this condition could be considerably improved by increased awareness of its existence and early referral for treatment as an elective surgical procedure.

Acute Disease↗
PubMed1979

Long term results of autogenous vein bypass grafts in femoropopliteal arterial occlusion.

The results of 329 consecutive autogenous vein grafts carried out between January 1962 and June 1973 have been reviewed. The 5- and 10-year mortality rates were 14.6 per cent and 18.7 per cent respectively. The corresponding patency rates were 70 per cent at 5 years and 34 per cent at 10 years, the lowest patency (27.8 per cent) occurring in below-knee anastomoses with grafts of 5 mm or less in diameter. As other have noted, the state of the popliteal--tibial run-off vessels had a considerable influence on long term patency rates. In severely ischaemic limbs, the limb salvage rate following this operation was 77 per cent. An analysis of symptoms, associated disease and complications is presented and discussed. No valid conclusions could be made regarding the effect of lumbar sympathectomy and postoperative anticoagulants on long term patency. This review has confirmed the findings of earlier studies that a satisfactory 5-year patency rate and a gratifying limb salvage rate can be achieved with an extremely low operative mortality rate of 0.37 per cent. Despite the presence of widespread atherosclerotic arterial disease, the 5-year mortality rate is 14.6 per cent, indicating that an attempt at reconstructive surgery is usually well worth while.

Adult↗
PubMed1975

Studies on gonococcal infection. I. Electron microscopic studies on phagocytosis of Neisseria gonorrhoeae by macrophages.

Macrophages from mice were infected with Neisseria gonorrhoeae type 1 cells, and their ultrastructure was studied by electron microscopy. The macrophages showed various stages of engulfment and digestion of gonococci 2 hr after infection. Infected macrophages seemed to develop pseudopodia for phagocytosis, and could engulf more than 30 gonococcal cells. Some engulfed bacteria appeared morphologically intact, while others appeared lysed and some structures resembling the L form of N. gonorrhoeae were also seen. These observations suggest that gonococcal cells may be able to survive intracellularly with normal or altered forms of morphology, and that macrophages containing these bacteria may disseminate gonococcal infection in man.

Animals↗
PubMed1971

Place of Achilles tenotomy in the treatment of severe intermittent claudication.

Achilles tenotomy was performed on 66 limbs in 60 patients with severe intermittent claudication and the results were assessed two years later. Early improvement occurred in half of them but decreased to 17% two years postoperatively. Sympathectomy did not influence the result. The postoperative morbidity was 14%, and 21% of limbs were subsequently amputated. The late mortality in the group studied was 8%.

Achilles Tendon↗