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Biomedical subjects

P M Schofield

Publications and source records attributed to P M Schofield.

101 records · Page 6Linked to original sources
PubMed1985

Preoperative and postoperative pulmonary function tests in patients with atrial septal defect and their relation to pulmonary artery pressure and pulmonary:systemic flow ratio.

Pulmonary diffusing properties and lung volumes were investigated in 44 patients with atrial septal defect, and in 30 of them preoperative and postoperative data were obtained. The patients were divided into three groups according to mean pulmonary artery pressure: less than or equal to 15 mm Hg (group 1), 16-29 mm Hg (group 2), and greater than or equal to 30 mm Hg (group 3). Patients in groups 1 and 2 had a high carbon monoxide transfer test which became normal after surgical correction of their septal defect. In group 3, the carbon monoxide transfer test was normal both before and after operation. As mean pulmonary artery pressure increased there was a progressive reduction in both forced expiratory volume in one second and vital capacity. Patients in group 3 had a low forced expiratory volume in one second, a low vital capacity, and a reduced forced expiratory volume in one second:vital capacity ratio. These abnormalities were not corrected by surgical closure of the septal defect. Formulas were derived from the lung function data, to predict the mean pulmonary artery pressure and the pulmonary:systemic flow ratio. The values predicted when these two formulas were applied to data obtained for patients in this study correlated well with measured values.

Adolescent↗
PubMed1984

Myocardial depression in streptococcal cellulitis.

A previously healthy woman developed streptococcal cellulitis of the leg after falling and lacerating her knee. On admission her blood pressure was unrecordable and her respiratory rate greater than 60 beats/minute. Mechanical ventilation was necessary, and plasma volume expansion was started, with little effect. Infusion of dopamine restored the blood pressure to 150/90 mm Hg, but interrupting the infusion for as little as 30 seconds resulted in profound hypotension. Insertion of a second central venous catheter allowed the dopamine to be given continuously, and the infusion was stopped successfully four days after her admission. She eventually made a complete recovery. This case highlights the need for intensive supportive treatment in many streptococcal infections and, in particular, the need for inotropic support.

Adult↗
PubMedDate not supplied

Endogenous brain norepinephrine levels following bilateral olfactory bulb ablation.

Changes in endogenous norepinephrine (NE) levels after bilateral olfactory bulb section have been found to occur in the rat brain. Since olfactory tract projections are confined to the ventral adrenergic pathway, and this pathway projects to the pyriform cortex, it was decided to examine the distribution of endogenous NE between the pyriform cortex and the remaining neocortex. It was demonstrated that significant reductions in NE content occurred in both brain regions, although the greater reduction occurred in the pyriform cortex. there were no significant changes in hypothalamic NE. It is concluded that sensory deprivation plus olfactory system damage induce specific changes in central function, which relate to noradrenergic pathways.

Animals↗
PubMedDate not supplied

The use of exercise technetium-99m 2-methoxy-isobutyl-isonitrile (99mTc-Sestamibi) perfusion scanning in the detection of acute rejection after cardiac transplantation.

Acute cardiac rejection remains an important cause of death during the first year following cardiac transplantation. Right ventricular biopsies at regular intervals are the main method of detecting rejection, although it is invasive. Unfortunately, non-invasive methods of detecting rejection have not proved reliable enough to replace cardiac biopsies. We assessed the usefulness of technetium-99m 2-methoxy-isobutyl-isonitrile (99mTc-Sestamibi) perfusion scanning in detecting acute rejection in 12 human orthotopic cardiac transplant recipients. Rest and exercise studies and right ventricular biopsies were performed on two occasions. Isotopic evidence of rejection was defined as a perfusion abnormality on either the resting or exercise studies. 99mTc-Sestamibi studies successfully identified acute rejection in 8 of 11 rejection episodes (p less than 0.04). The calculated sensitivity and specificity of 99mTc-Sestamibi scanning were both 72%. Perfusion scanning with 99mTc-Sestamibi may be useful in the diagnosis of acute rejection in cardiac transplant recipients.

Adult↗
PubMedDate not supplied

Heart transplantation in the United Kingdom: who waits longest and why.

BACKGROUND: This study aims to identify characteristics that increase the chance of death of potential cardiac transplant recipients before donor organs become available. METHODS: Between June 1, 1988, and May 31, 1993, 332 patients were accepted for heart transplantation; 235 underwent surgery. Ninety-seven patients had not received transplants; of these, 71 died, 13 were transferred to other lists, and 13 were awaiting organs at the close of the study. Median waiting time for those patients who received organs was 109 days, whereas patients who did not receive organs spent a median of 94 days on the list. Recipients are matched to donor organs according to blood group, size (height), and, recently, preoperative transpulmonary pressure gradient. Recently cytomegalovirus antibody mismatches (positive donor to negative recipient) have been avoided where possible. These factors, together with age, gender, underlying diagnosis, previous heart surgery, and Toxoplasma antibody status were studied to assess their influence on waiting time and survival. RESULTS: No characteristics were found significantly to influence survival after acceptance, so that the chance of death while the patient was waiting for heart transplantation is mainly affected by the severity of disease and the length of time a patient waits. In multivariate analyses the following were independently significantly associated with shorter waiting times: small patients (< 1.7 m tall; p = 0.005), patients with blood types B and AB (p = 0.003), and patients with cardiomyopathy (p < 0.001). CONCLUSIONS: These results can be used by cardiologists to help assess the time at which a patient should be referred for transplantation.

Blood Grouping and Crossmatching↗
PubMedDate not supplied

A method of analyzing the onset and progression of coronary occlusive disease after transplantation and its effect on patient survival.

The development of transplant-acquired coronary occlusive disease is monitored with serial angiography and is graded on a three-point scale as normal, mild (< 50% stenosis), or severe (> or = 50% stenosis). Previous studies have provided information about the time to the first sign of disease on angiography or empirical descriptions of progression. The number of observed transitions between grades of disease has been recorded, and a Markov model based on these transitions is used to estimate the rate of progression through angiographically defined disease grades and the mortality rates from each grade. Five hundred thirty-six angiograms from 240 patients were analyzed. Fifty-three graft failures occurred. The annual transition rate per patient year from normal to mild disease was low, 0.120 (95% credible interval, 0.096 to 0.154), although the transition from mild to severe disease was relatively high, 0.482 (95% credible interval, 0.325 to 0.671). Annual death rates from normal, mild, and severe grades were 0.032 (95% credible interval, 0.016 to 0.052), 0.076 (95% credible interval, 0.007 to 0.187) and 0.415 (95% credible interval, 0.244 to 0.640), respectively. Before onset of disease patients have a hazard-free course, and mild disease displayed on angiography is relatively non-life-threatening. However, once mild disease has been detected by angiography, progression to severe disease is rapid, and severe disease carries a very poor prognosis.

Adolescent↗
PubMedDate not supplied

Lack of association between endomyocardial evidence of rejection in the first six months and the later development of transplant-related coronary artery disease.

The development of transplant-related coronary artery disease (TCAD) is the major determinant of long-term heart transplant survival. To test the hypothesis that TCAD might be related to cellular myocardial rejection, the grades of rejection seen at all biopsies performed in the first 6 months after heart transplantation were analyzed in 108 patients who survived more than 6 months. The development of TCAD was assessed at routine follow-up coronary angiography in 101 patients and at necropsy in seven patients. This data was analyzed with Kaplan-Meier survival curves and Cox proportional hazard regression analysis. No significant association was found between either moderate rejection or any level of rejection and the later development of TCAD, nor did the absence of any rejection protect against its development.

Biopsy, Needle↗