Biomedical subjects

J Wallwork

Publications and source records attributed to J Wallwork.

363 records · Page 21Linked to original sources

PubMedDate not supplied

Activation of the alternative pathway of complement in hyperacute xenograft rejection of rabbit hearts by human blood.

Isolated rabbit hearts were perfused as autoperfusing working preparations with human blood to simulate discordant hyperacute xenograft rejection. Perfusion with unmodified human blood resulted in immediate thrombotic failure of the hearts. This process was initiated by immunoglobulin M heterophile human anti-rabbit antibody, mediated by the classic pathway of complement and platelet-activating factor, and effected by platelets. Prevention of this process resulted in organ damage by another process occurring at about 20 minutes. Removal of heterophile antibody from the perfusing blood had no effect on this second event, but specific inactivation of the alternative pathway of complement prevented its generation despite normal titers of antibody and normal classic pathway activity. Studies of the deposition of components of the human complement system on the endothelium of the xenoperfused hearts confirm a role for the alternative pathway of complement in xenograft rejection in this discordant species combination.

Acute Disease↗

PubMedDate not supplied

Cardiovascular dysfunction. A rationale for characterization and a guide to therapy.

Traditional clinical assessment of cardiac function has relied on the indirect measurement of systemic blood pressure, heart rate and rhythm, and central venous pressure. However, because the circulation comprises complex interactions between flow and impedance in two hydraulic systems coupled in series, the usual assumptions drawn from the measurement of only a representative sample of this system can lead to serious errors in interpretation. This is particularly significant in conditions leading to physiologic distortions. Patients undergoing major surgery, or with suspected cardiac dysfunction, can only be adequately managed with a knowledge of both right and left heart pressures, together with the measurement of cardiac output. This report presents a rationale for the use of a simple method for interpreting these data and a guide to optimizing management. For those patients with heart failure who are unable to be sustained with conventional pharmacology, criteria are suggested that may help the clinician decide when more aggressive intervention, such as mechanical assist, is required.

Biometry↗

PubMedDate not supplied

Audit of referral and explant diagnoses in lung transplantation: a pathologic study of lungs removed for parenchymal disease.

BACKGROUND: Lung transplantation is performed for an increasing range of pulmonary conditions in which the diagnosis is often clinical or based on limited biopsy material. Diagnosis may be made late in the course of the disease where specific features are no longer present. Posttransplantation complications and disease recurrence may relate to the primary disease, and accurate diagnosis is therefore essential. METHODS AND RESULTS: A pathologic review of 183 explanted lungs over a 10-year period (heart-lung = 109, single lung = 65, double lung = 9) showed 29 significant discrepancies or additional features likely to effect outcome. The final pathologic diagnosis was cystic fibrosis (n = 66), emphysema (59), bronchiectasis (17), pulmonary fibrosis (19), sarcoidosis (10), Langerhans cell histiocytosis (3), pulmonary veno-occlusive disease (3), posttransplantation obliterative bronchiolitis (2), primary hemosiderosis (1), rheumatoid obliterative bronchiolitis (1), extrinsic allergic alveolitis (1), pneumoconiosis (1). Unsuspected diagnoses included tuberculosis (8) (four cases of which were active and in single lung recipients requiring antituberculous chemotherapy), sarcoidosis (9), (of which, six were unsuspected primary diagnoses and three were additional diagnoses), veno-occlusive disease (3), carcinoma (1), pneumoconiosis (1), and pulmonary fibrosis (2). Aspergillus infection (2) and bronchocentric granulomatosis (3) were found in patients with cystic fibrosis. One active tuberculosis case also showed an aspergilloma. Unsuspected infections requiring therapy in immunosuppressed patients and previously unsuspected sarcoidosis, which is known to recur in the graft, were the major novel diagnoses. Discrepancy rate was 12 of 65 in single lungs (19%) and 17 of 109 in heart-lungs (16%). CONCLUSIONS: These results emphasize the need for accurate preoperative diagnosis especially when the similarly diseased native lung remains in situ.

Adult↗