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Biomedical subjects

D N Ross

Publications and source records attributed to D N Ross.

At least 91 records · Page 5Linked to original sources
PubMed1979

Observations on glutaraldehyde-treated heterologous cardiac valves.

Recent publications on commercial porcine bioprosthetic cardiac valves have stated that the endothelium disappears during the glutaraldehyde processing and that in many cases histological evidence of early tissue deterioration was found. Our experiences have shown that porcine aortic valves can be processed in glutaraldehyde without loss of the integrity of the endothelium and with the development of optimum collagen fibre structure. The valve mounted in a Dacron tube is not restricted in diameter and performs well under biological conditions up to a period of six months.

Aldehydes↗
PubMed1978

Storage of heart valve allografts in glycerol with subsequent antibiotic sterilisation.

Fresh allograft valves stored in a nutrient medium at +4 degrees C have a limited storage time of eight weeks. Dura mater has been stored in glycerol for longer periods, and this paper presents work on the glycerol storage of allograft heart valves. The elastic properties of the valve cusps showed a fall during storage in glycerol that was associated with an altered histological appearance of the cusp tissue. The loss in nuclearity in the histological sections of stored tissue was partially responsible for the observed decrease in viability during storage. All these changes during storage in glycerol, or glycerol and subsequent antibiotic treatment, were similar to the changes seen in valves stored in a nutrient medium. Glycerol therefore offers an alternative storage system to the cold nutrient medium but has no practical advantages. Glycerol alone will not sterilise the allograft tissue, and a post-storage treatment with antibiotics is essential.

Anti-Bacterial Agents↗
PubMed1977

Elasticity of frozen aortic valve homografts.

Homograft aortic valves were treated and stored in different ways and then tested for elastic qualities. It appears from the findings that the most satisfactory long-term storage technique is to flash-freeze the valves in the presence of dimethyl sulphoxide immediately after dissection.

Aortic Valve↗
PubMed1977

A re-evaluation of antibiotic sterilisation of heart valve allografts.

Six different mixtures of antibiotics used for treating heart valve allografts at the National Heart Hospital have been compared and the formulation of the medium in current use is described. The abilities of antibiotic-resistant bacteria, and of fungi with low sensitivities to antifungal agents, to survive treatment are also described. These abilities emphasise the need for routine microbiological screening of every valve.

Anti-Bacterial Agents↗
PubMed1976

Geriatric day hospitals: counting the cost compared with other methods of support.

The past decade has seen a great expansion of the day-hospital element in geriatric and psychiatric care, and the merits of such therapeutic agencies have been described quite often--but with little reference to the economic benefit to the community. We have described an enquiry into the true cost of a typical 'intermediate' day hospital and introduced valid comparisons with other methods of caring for the elderly sick or frail: these comparisons inevitably led to the inclusion of the acute general hospital when considering the integrated health and welfare service which we require. The surprising financial implications should be recognized as we enter another era of stringency which must restrict development of the National Health Service.

Aged↗
PubMed1976

Reconstruction of right ventricular outflow tract with a valved conduit in 75 cases of congenital heart disease.

Reconstruction of the right ventricular outflow tract with an aortic homograft conduit was performed in 75 patients from 1966 to 1974. The types of congenital heart disease were as follows: pulmonary atresia, 35 cases; severe tetralogy of Fallot, 22 cases; truncus arteriosus, 6 cases; transposition of the great arteries (TGA), 3 cases; single ventricle, 2 cases; and tricuspid atresia, 7 cases. Ninety per cent of the patients had one or more previous shunts, and this was a factor affecting the mortality rate. Other factors included age, pulmonary vascular resistance, surgical anatomy, and technical problems such as bleeding, prolonged bypass, coronary artery injury, and compression of the conduit by the sternum. Our present approach is to avoid shunts, define the anatomy precisely by angiography, and to attempt total correction when severe hypoxia or effort intolerance occurs or before increased pulmonary vascular resistance develops.

Adolescent↗
PubMed1975

Analysis of homograft valve failure in 311 patients followed up to 10 years.

Homograft aortic valve replacement was performed in 311 patients at the tnational Heart thospital, London, between 1964 and 1973. Valve failure has occurred in 61 patients (20%), 32 of whom survived reoperation. From 1963 through 1967, 156 valves were freeze-dried and account for 56 of the valve failures. From 1968 to 1973, 118 fresh or fresh-frozen valves resulted in only 5 failures. Six general types of failure have been identified: calcification (13), dehiscence (15), infective endocarditis (17), prolapse (6), cusp degeneration (5), and tear or perforation (5). Valve failure may be due to surgical technical error resulting in dehiscence or valve incompetence, or it may be related to degenerative changes in the homograft. The clinical results, supported by gross and histological examination and viability testing, enable us to conclude that fresh or fresh-frozen valves are superior to freeze-dried valves, having resulted in only 4% valve failure over the past five years.

Aortic Valve↗
PubMed1975

Aortic regurgitation from infective endocarditis in Fallot's tetralogy and pulmonary atresia.

Three cases of aortic regurgitation acquired as the result of bacterial endocarditis complicating Fallot's tetralogy and pulmonary atresia have been described. One also had mitral regurgitation from a 'jet lesion' of the anterior cusp of the mitral valve. Surgical treatment of all abnormalities with aortic valve repair or replacement was undertaken in each patient and was successful in two. Difficulties in diagnosis and surgical treatment are discussed.

Adult↗
PubMed1975

Fascia lata valves: a clinicopathological study.

Sixteen frame-mounted fascia lata valves removed from the mitral, aortic or--in one patient--pulmonary position have been detailed histologically. These valves had remained in 15 patients (11 men and four women) for periods varying between 10 and 44 months. The reason for the original transplantation was either chronic rheumatic endocarditis or calcific aortic disease. In the mitral position, the leaflet in position nearest the site of the original anterior mitral valve cusp showed the least changes. The remaining two leaflets of the fascia lata valve in the mitral position, as well as those removed from the aortic or pulmonary position, showed more severe changes; these consisted of degeneration of collagen tissue and often a severe decrease of nuclei belonging to the fibroblastic series. These changes, as well as superimposition of fibrin or fibrous tissue, tended to become more pronounced the longer the valve had remained in the patient. Viability studies in valves removed from two patients have also been undertaken showing very greatly reduced activity. The possible causes for valve dysfunction have been reviewed, and the findings in this study suggest that contraction of fibrous tissue, which sandwiches the fascia lata valve cusps, may contribute to failure of satisfactory valve function. It is concluded that fascia lata forms a poor substitute for replacement of diseased cardiac valves.

Adult↗
PubMed1975

Adult cyanotic congenital heart disease.

The surgical treatment of cyanotic heart disease in the adult poses some technical difficulties in correcting severe anatomical deformities and compromised physiological states over a wide range of conditions. Various abnormalities and their surgical management have been reviewed. Forty-six patients over the age of 18 years have been operated with 10 operative deaths. Of the survivors, 63% have had excellent clinical result; 69.5% of the total group had an excellent or good result following surgery. It is concluded that the age of the patient is not a bar to the complete repair of these deformities, and all cases of adult cyanotic heart disease should be investigated with a view to surgical correction.

Adolescent↗
PubMed1975

Mononeuritis multiplex: a complication of open-heart surgery.

A prospective examination of all patients undergoing cardiopulmonary bypass in one unit revealed that a number of peripheral nerve lesions occurred during the postoperative period. These were documented over a period of 20 months with follow-up of those patients so affected.

Adult↗
PubMed1975

Primitive ventricle with acquired subpulmonary stenosis.

The course and natural history of two children aged 1 yr and 5 yr with primitive ventricle with outlet chamber and normally related great arteries are described. They initially presented as ventricular septal defect with increased pulmonary blood flow and subsequently developed 'cyanotic attacks', chronic cyanosis and diminished pulmonary flow by acquiring subpulmonary obstruction of the bulboventricular foramen. Both had successful surgical treatment utilizing their own normal pulmonary valves by connecting the right atrium to the right ventricular outflow, with a Dacron conduit in one, and in the other by detaching the pulmonary artery and valve from the rudimentary outflow chamber and anastomosing it directly to the right atrial appendage. Changing morphology and its effect on function are discussed.

Cardiomyopathy, Hypertrophic↗