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Biomedical subjects

T W Higenbottam

Publications and source records attributed to T W Higenbottam.

At least 91 records · Page 5Linked to original sources
PubMed1990

Herpes simplex virus infection in heart-lung transplant recipients.

We report our experience of herpes simplex virus infection in a series of 51 recipients of heart lung transplantation (HLT). Nine patients, all of whom were seropositive for the virus preoperatively, developed HSV infection. Seven episodes of culture-proved mucocutaneous HSV infection without evidence of pulmonary involvement occurred in four patients. Six episodes of HSV pneumonia were seen in a further five patients, one of whom died. Diagnosis of HSV pneumonia was by histological appearances on transbronchial biopsy, together with culture of lung tissue or bronchoalveolar lavage. Concomitant cytomegalovirus infection occurred in four patients. All patients who developed HSV pneumonia did so within the first two postoperative months; in four patients following augmented immunosuppression. We now suggest that HLT recipients who are HSV antibody-positive should receive prophylactic acyclovir for the first two months after surgery and at times of augmented immunosuppression.

Acyclovir↗
PubMed1990

Impairment of pulmonary endothelium-dependent relaxation in patients with Eisenmenger's syndrome.

A comparison has been made between the endothelium-dependent relaxation of pulmonary arteries (PA) obtained at heart-lung transplantation from 4 patients with Eisenmenger's syndrome and secondary pulmonary hypertension, and PA obtained at lobectomy from 4 patients with lung carcinoma, the controls. All vascular rings were studied immediately after lung excision. PA rings from control patients dose-dependently relaxed to cumulative doses of acetylcholine (ACh, 10(-10) to 10(-5) M), achieving a maximal relaxation of 80 +/- 5% (mean +/- s.e. mean) from precontraction with phenylephrine. By contrast, PA rings from Eisenmenger's syndrome patients achieved a maximal relaxation of only 34 +/- 12% (P less than 0.05, unpaired t test), with even paradoxical contraction at high doses of ACh (10(-6) to 10(-5) M). Sodium nitroprusside (10(-4) M) relaxed all PA rings, with and without endothelium (carefully removed before study), obtained from both control and Eisenmenger's syndrome patients. These results provide the first evidence that endothelium-dependent relaxation of PA mediated by endothelium-derived relaxing factors is impaired in Eisenmenger's syndrome patients with secondary pulmonary hypertension.

Acetylcholine↗
PubMed1990

Hypertensive exercise responses in ciclosporin-treated normotensive renal transplant recipients.

Although many patients taking ciclosporin (CS) for the long term develop hypertensive side effects, a proportion do not. We have studied the blood pressure response to graded upright bicycle exercise while continuously recording the metabolic rate in 18 normotensive renal transplant recipients whose mean age was 30.8 years (range 16-54). Nine were treated with CS alone and 9 with azathioprine and a steroid, prednisolone (AzS). Both groups performed a progressive exercise test, with work increasing by 25 W every 4 min from rest. All patients completed a workload of at least 75 W during the test. A group of 8 normal subjects whose mean age was 29 years (range 19-44) were exercised with the same protocol. The CS group had a significantly higher mean systemic blood pressure at both 50 and 75 W (124 and 132 mm Hg, respectively), compared with the AzS group (103 and 108 mm Hg; p less than 0.01). The blood pressure response to exercise in the AzS group was similar to that observed in the normal group. This was despite a higher metabolic rate at each stage of work in the AzS group as compared with the CS or normal groups. Despite being normotensive at rest, renal transplant patients who are treated with CS have evidence of a vasopressor effect, with systemic vascular resistance inappropriately high for exercise, implying reduced compliance of the vascular bed.

Adolescent↗
PubMed1990

Pulmonary hypertension in a lupus clinic: experience with twenty-four patients.

The clinical and serological findings on 24 patients with pulmonary hypertension (PHT) seen at the Lupus Clinic of St. Thomas' Hospital, London are presented. Twenty-two patients had systemic lupus erythematosus (SLE), one other a primary antiphospholipid syndrome and another an SLE/progressive systemic sclerosis (PSS) overlap syndrome. In 21 of the 24 patients, the disease resembled the primary idiopathic variety with clear lung fields and no clinical evidence of pulmonary thromboembolism, although angiography and nuclear perfusion scans were not performed. Two patients clearly suffered from thromboembolic PHT, one with SLE and one with an antiphospholipid syndrome. One patient with SLE/PSS overlap syndrome developed pulmonary fibrosis. The frequency of antiphospholipid antibodies (lupus anticoagulant and antibodies to cardiolipin was 68% which appears to be higher than generally found in patients with SLE, and the clinical significance of this finding is unknown. Other associated features of the antiphospholipid syndrome in this group were uncommon. Death occurred in 13 of the 24 patients, 4 were lost to followup and 7 are known to be alive. The cause of death was circulatory failure in the majority; sudden death once this complication occurred was particularly common. One patient died from adult respiratory distress syndrome and one from hemorrhagic shock while undergoing heart/lung transplantation. Two patients underwent successful heart/lung transplantation. One, however, died of a mesenteric occlusion and bowel infarction following a second lung transplantation because of rejection of the first heart/lung transplantation after one year. The other patient is alive and well 2 years later.

Adult↗
PubMed1990

Atrial natriuretic peptide in primary pulmonary hypertension.

Plasma levels of atrial natriuretic peptide (ANP) were determined during cardiac catheterization in nine patients with primary pulmonary hypertension (PPH) and the effect of prostacyclin infusion via a right heart catheter studied. The role of hypoxia on the release of ANP was investigated in a control group of six normal subjects who underwent an acute hypoxic challenge. Patients showed the typical haemodynamic changes of primary pulmonary hypertension with elevation of mean (SD) pulmonary artery pressure, 71.3 (13.8) mmHg, and low cardiac index, 1.9 (0.5) l.min-1.m-2. Plasma ANP was also elevated; mean pulmonary artery plasma ANP was 96.3 (77.6) pmol.l-1 in PPH patients compared with mean venous plasma ANP of 8.9 (5.6) pmol.l-1 in normal subjects. Prostacyclin infusion in PPH patients and hypoxic challenge in normal subjects did not significantly alter plasma ANP levels. The elevated levels of ANP in PPH are due to the altered haemodynamics secondary to increased pulmonary vascular resistance and may be responsible for the lack of peripheral oedema seen in this condition.

Adult↗
PubMed1990

Transbronchial biopsies in children after heart-lung transplantation.

Sixty transbronchial biopsies have been performed in eight children after heart-lung transplantation. The selection of fiber-optic bronchoscope or a small (4 mm; 30 cm) rigid bronchoscope was made according to the size of endotracheal tube required at surgery. If the endotracheal tube was size 7.5 or greater, a fiber-optic bronchoscope was used, whereas if the endotracheal tube size was below 7, a rigid bronchoscope was used. For the diagnosis of lung rejection, the histology of biopsies revealed a sensitivity of 91% and specificity of 69% (similar to the result in adults). The histology also distinguished lung infection from rejection. Complications included three pneumothoraces and two clinically significant episodes of hemorrhage, one of which led to a cardiorespiratory arrest, which may have been caused by hypoxia. As a result, arterial oxygen saturation is now monitored during the procedure using a pulse oximeter.

Adolescent↗
PubMed1990

Acetylcholine and adenosine diphosphate cause endothelium-dependent relaxation of isolated human pulmonary arteries.

Endothelium-dependent vasorelaxation mediated by endothelium-derived relaxing factors (EDRF) has been extensively studied in animals but only limited studies in man are available. Demonstration of EDRF-mediated dilatation of human vessels is fundamental for understanding the mechanisms of vascular diseases in man. We have investigated endothelium-dependent relaxation of isolated human pulmonary arteries. Vascular segments, taken from uninvolved regions of resected lung from eight patients undergoing lobectomy for lung carcinoma, were cut into rings. In rings precontracted with phenylephrine, both acetylcholine (ACh) and adenosine diphosphate (ADP) induced dose-dependent relaxation in the presence of endothelium but not when the endothelium had been carefully removed. The rings without endothelium relaxed completely with sodium nitroprusside, a vasodilator agent acting directly on vascular smooth muscle. Pre-incubation with indomethacin, a cyclo-oxygenase inhibitor which blocks production of prostacyclin, did not alter the vasorelaxant responses to ACh and ADP, suggesting that one (or several) non-prostanoid EDRF(s) are responsible for the endothelium-dependent relaxation of isolated human pulmonary arteries.

Acetylcholine↗