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Biomedical subjects

J Wallwork

Publications and source records attributed to J Wallwork.

At least 307 records · Page 17Linked to original sources
PubMed1987

Biopsy assessment of fifty hearts during transplantation.

The aim of the study was to evaluate myocardial protection during the transportation of human donor hearts stored at 4 degrees C in crystalloid cardioplegic solution. Biopsies were performed on 50 donor hearts before excision and at four subsequent time intervals during transplantation. Quantitative birefringence measurements on cryostat sections of the left ventricular biopsy specimens were used to assess myocardial function. Fifteen donor hearts had poor birefringence assessments before excision, and 67% received inotropic support after implantation; 22 deteriorated during transportation, and 50% received inotropic support; 13 were unchanged throughout the procedure, and none required inotropic support. This study demonstrates the need for improved protection of donor hearts during transportation and recommends the use of rigorous criteria in the selection of these hearts.

Adolescent↗
PubMed1986

Concurrent cytomegalovirus and Coxsackie B virus infections in a heart-lung transplant recipient.

A 35-year-old woman with fibrosing alveolitis was given a combined heart and lung transplant at Papworth Hospital, Cambridge. Although her immediate post-operative course was satisfactory, she subsequently experienced concurrent primary cytomegalovirus and Coxsackie B virus infections associated with significant morbidity including pancreatitis. She made a full recovery and has remained well for more than 2 years after transplantation.

Adult↗
PubMed1986

Impromidine is a partial histamine H2-receptor agonist on human ventricular myocardium.

The inotropic effects of impromidine have been studied and compared with those of histamine on human isolated left ventricular preparations stimulated at 1 Hz. Both drugs caused concentration-related increases in force of contraction and were of similar potency, although the maximum response to impromidine was markedly and significantly less than that to histamine. The positive inotropic responses of impromidine were inhibited by cimetidine 1 X 10(-5) M, consistent with histamine H2-receptor involvement. Impromidine 1 X 10(-4) M inhibited maximal responses to histamine to a level equal to the maximal impromidine response; however, impromidine did not inhibit responses to isoprenaline. Positive inotropic activity and inhibition of maximal responses to histamine occurred over a similar impromidine concentration-range. Impromidine displaced histamine concentration-response curves to the right, whereas mepyramine had no effect on responses to histamine. It is concluded that impromidine has positive inotropic activity on the human ventricle, that the response is mediated via histamine H2-receptors, and that impromidine is a partial agonist compared with histamine.

Female↗
PubMed1986

Surgical pathology of the thymus: 20 years' experience.

Fifty five patients underwent thymic surgery at Papworth Hospital from April 1964 to March 1984. The number presenting and the percentage with symptoms annually remained unchanged during this period. Forty four of these 55 patients had tumours. Twenty eight had thymomas (18% of whom had myasthenia gravis and 7% red cell aplasia), nine Hodgkin's disease, four germ cell tumours, and three secondary carcinomatous tumours. Five tumours were cystic. Six further patients had non-tumourous cystic lesions (four simple, one foregut, one lymphangiectatic). The remaining five patients had follicular hyperplasia; all of these had myasthenia gravis. Complete excision was performed in 41 of the 55 patients. So far survival is 100% in those with benign lesions other than benign thymomas, where the survival was 70% at five years. Those with malignant thymomas had a 60% survival rate at five years and those with Hodgkin's disease 29%.

Adolescent↗
PubMed1986

Transvenous lung biopsy in the pig.

At present there is no satisfactory technique for repeated lung biopsy in recipients of heart-lung transplants. A new technique for lung biopsy, which might be adopted for this purpose, has been developed. A Teflon sheath is inserted through the jugular vein into the pulmonary artery with the aid of a balloon catheter. A flexible biopsy forceps is then introduced through the sheath into the pulmonary arterial tree and advanced into the periphery of the lung, where biopsy samples are taken. The procedure was attempted in 14 pigs. Initially crocodile jaw (two pigs) and fenestrated cups forceps (five pigs), which are currently in use for transbronchial lung biopsy, were used. Subsequently the biopsy forceps was modified and the jaws were replaced by a cutting needle mechanism (six pigs). Out of the 13 animals in which the procedure was technically possible, lung parenchyma was obtained from nine and pulmonary arterial wall from 11. One animal died shortly after the procedure. The cause of death could not be determined with certainty at postmortem examination. There was, however, a small tear on the surface of the lung, which could have produced a tension pneumothorax. The other 12 animals recovered from the procedure. They were killed 24 hours later and postmortem examination was carried out. One animal in which the crocodile jaw forceps had been used had a haematoma in the lower lobe (3 X 3 X 4 cm) and 100 ml of blood in the pleural cavity. In the other 11 animals, in which the fenestrated cups or the cutting needle forceps had been used, the intrapulmonary haematomas were 1-2 cm in diameter and the pleural surface was intact. It is concluded therefore that transvenous lung biopsy is feasible and that this procedure might find an application in monitoring rejection in recipients of heart-lung transplants.

Animals↗
PubMed1985

The effect of surgery with cardiopulmonary bypass on alveolar-capillary barrier function in human beings.

We measured the rate of clearance of technetium 99m-labeled diethylenetriamine pentaacetate (99mTcDTPA) (molecular weight, 492 daltons) from the lung into the blood (T1/2LB) in 9 patients before and after operation with cardiopulmonary bypass (CPB). Two hours postoperatively, T1/2LB fell from 49.3 +/- 13.6 minutes (mean +/- standard deviation) to 24.0 +/- 12.8 minutes (p less than 0.001). In addition, alveolar-arterial oxygen tension difference P(A-a)O2 had increased from 73 +/- 28 mm Hg to 164 +/- 37 mm Hg (p less than 0.001). The rates of clearance of 99mTcDTPA had returned to preoperative times by 7 days after operation, although there was still a significant (p less than 0.05) elevation in P(A-a)O2. Postoperative respiratory failure developed in 1 patient. The only abnormality of lung function detected preoperatively was an increased clearance rate for 99mTcDTPA (T1/2LB, 18 minutes). This study has shown an increased clearance from the lung of a low-molecular-weight molecule following operation with CPB. This finding should allow a more rational approach to elucidating the mechanisms of injury to the gas-blood interface in the lung following this type of operation.

Aged↗
PubMed1985

Haemodialysis and haemofiltration on cardiopulmonary bypass.

Over a three year period we have used haemodialysis and haemofiltration in parallel with cardiopulmonary bypass in 26 patients. Impaired renal function and excessive fluid retention have been the main indications. Patients on haemodialysis programmes for end stage renal failure did not require further dialysis until at least the third postoperative day, when they could tolerate the haemodynamic disturbance of dialysis. In the other patients these techniques proved valuable in reversing the effects of haemodilution and in controlling the concentration of serum potassium. Our experience has confirmed that haemodialysis and haemofiltration in parallel with cardiopulmonary bypass are useful adjuncts in the perioperative management of patients with impaired renal function undergoing open heart surgery. The techniques are also effective in correcting the fluid retention and biochemical imbalance in patients with congestive cardiac failure, including those with heart transplants.

Adolescent↗
PubMed1985

Incidence and aetiology of a raised hemidiaphragm after cardiopulmonary bypass.

A raised hemidiaphragm has been reported as an uncommon complication of cardiopulmonary bypass, possibly resulting from cold injury to the phrenic nerve. At Papworth Hospital myocardial protection during cardiac arrest relies in part on irrigation of the pericardial cavity with large volumes of Hartmann's solution at 4 degrees C. Retrospective review of the chest radiographs of 100 consecutive patients undergoing cardiopulmonary bypass showed that 31 had a raised left hemidiaphragm soon after operation. The only significant correlation was with aortic cross clamp time (p less than 0.03). A prospective study of 36 consecutive patients undergoing cardiopulmonary bypass was then undertaken with diaphragmatic screening and chest radiography. Preoperative screening gave normal results in all patients. In the early postoperative period 16 (44%) had left diaphragmatic weakness or paralysis, two (5.5%) right sided weakness, and two (5.5%) bilateral weakness. Repeat screening of these patients showed resolution in all but four cases (80%) at six months and in all but two (90%) at one year. The greater number of left sided lesions than of right (8:1) is probably due to the fact that the cold jet of irrigating fluid is directed towards the left phrenic nerve. These findings have implications with regard to the optimum temperature of the irrigant fluid for myocardial protection during cardiopulmonary bypass.

Adolescent↗
PubMed1985

Significance of donor transmitted disease in cardiac transplantation.

Infectious complications constitute a major cause of morbidity and mortality after heart transplantation. Those infections transmitted with the transplanted heart are potentially avoidable. Cytomegalovirus infections and toxoplasmosis occupy a prominent position in this category. The outcome of transplanting hearts from donors previously exposed to these infections depends largely on the existing immune status of the recipient. This paper is a retrospective study on the incidence of Toxoplasma gondii and cytomegalovirus infections in patients undergoing heart and heart-lung transplantation at Papworth Hospital, Cambridge.

Adolescent↗
PubMed1985

Is cyclosporine's nephrotoxicity related to its immunosuppressive effectiveness?

A fatal early acute rejection occurred in a heart allograft recipient immunosuppressed with Cyclosporine. This failure to prevent rejection in spite of satisfactory plasma levels of Cyclosporine was associated with total absence of renal impairment. The latter has always been present in our experience. The absence of immune and nephrotoxic effects raises the question of a biological defect in this patient, possibly a lack of specific receptors for Cyclosporine.

Cyclosporins↗
PubMed1985

[Ostium stenosis of both coronary arteries and latent hypothyroidism as sequelae of radiotherapy in Hodgkin disease].

Premature arteriosclerosis following irradiation is a known experimental and clinical phenomenon. Although the heart was once considered a relatively radioresistant organ, now all components, including the coronary arteries, are recognised as possible targets of radiation injury. We present a 40-year-old women who received extensive neck and thoracic radiation for treatment of Hodgkin's disease. Ten years later she developed severe coronary artery disease with ostium stenosis of the left and right coronary arteries, as well as subclinical hypothyroidism.

Adult↗
PubMed1984

Selection and procurement of hearts for transplantation.

The success of orthotopic heart transplantation depends wholly on satisfactory function of the new heart on completion of the operation. This in turn depends on the quality of the donor heart before its removal, the effectiveness of the methods used to preserve it during transport from the donor to the recipient hospital, and the accuracy of the operative procedure. From January 1979 to December 1983, 62 donor hearts were transplanted into 61 recipients at Papworth Hospital. These hearts were selected from 250 offered for consideration. The most common reasons for not proceeding with an initial inquiry were failure of the donor to meet the medical criteria for selection (77 cases) and lack of intensive care facilities or staff shortages such that a transplant could not be accommodated at the time of inquiry (80). Eight early deaths occurred, of which three were due to primary failure of the donor heart. Actual one and three year survivals for the whole programme were 58% and 50% respectively, the current actual one year survival being 70%. Forty per cent of patients selected for transplantation died while waiting for a heart to become available. Their average survival time was 46 days. The number of donor hearts referred for transplantation depends on public attitudes towards organ transplantation, the willingness of doctors looking after brain dead patients to seek permission from relatives for the heart to be donated, and the cooperation of local kidney transplant surgeons. A larger number of suitable donor hearts to choose from would enable more patients to be treated, as transplant operations could be arranged so that existing facilities were used to their maximum capacity.

Adolescent↗