Search PubMed⌕ Search

Biomedical subjects

D A Waller

Publications and source records attributed to D A Waller.

At least 73 records · Page 4Linked to original sources
PubMed1992

The use of transoesophageal echocardiography for detecting early recurrence of atrial myxoma.

A comparison between praecordial and transoesophageal cross-sectional echocardiography was undertaken in the follow-up of 14 patients who had previously undergone surgical excision of atrial myxoma. The mean interval between surgery and follow-up was 39 months. Evidence of recurrent tumour was seen in two patients by transoesophageal echocardiography but went undetected in one of these using the praecordial approach. Clear visualisation of the atria and interatrial septum was possible in all remaining cases using transoesophageal echocardiography and this allowed confident exclusion of tumour recurrence. Using praecordial echocardiography, technically inadequate studies meant that this was not possible in 4 patients. The significant late recurrence rate of excised atrial myxomas, emphasises the need for serial, postoperative echocardiographic studies. Praecordial echocardiography may be unreliable in the detection of recurrent atrial myxoma in its early stages and for this reason transoesophageal echocardiographic follow-up is justified in high risk patients.

Echocardiography↗
PubMed1992

Repair of asymptomatic aortic valve disease during other cardiac surgery.

Repair of asymptomatic aortic valve disease was performed in 12 patients (9 female, 3 male, mean age 57.5 years) undergoing other cardiac surgery. Stenosis was the predominant aortic valve lesion in 7 (group A) with a mean gradient of 33.4 mmHg and regurgitation of mean grade 1.4 was predominant in 5 (group B). Cusp debridement +/- commissurotomy was performed in 9; commissural resuspension in 6 and repair of cusp perforation in 2. Perioperative transoesophageal echocardiography was used to assess the adequacy of repair in 4 patients. Prospective precordial echocardiographic follow-up is complete (mean 4.3 months). In group A there has been a significant reduction is peak aortic pressure gradient (33.4 vs 22.1 mmHg, p less than 0.05) and in cusp thickness (2.25 to 1.64 mm, p less than 0.05). In group B the degree of incompetence has improved in 3 of the 5 patients. Three patients have worsened valve disease following repair; in all these there was mixed valve disease of rheumatic origin. Aortic valve repair of asymptomatic disease during other cardiac surgery is a feasible technique which does not accelerate the disease process in the short term. Long-term follow-up is in progress to assess the prognosis of this preventive intervention.

Adult↗
PubMed1992

Cognitive patterns in school-age children with end-stage liver disease.

Although children with end-stage liver disease (ESLD) have been found to have cognitive delays, the relationship between patterns of cognitive function and diagnostic category, age of onset, duration and severity of disease has not been assessed before transplantation. Verbal and performance IQ (VIQ, PIQ) scores and scores on Bannatyne's cognitive factors for 43 children with ESLD were compared with those of 15 control children with cystic fibrosis (CF) and with existing normative data. Children with biliary atresia had deficits in PIQ, spatial and sequential scores. Children with alpha-1 antitrypsin deficiency did not differ significantly from CF controls but did show deficits compared with normative data. Children with onset of disease in the first year of life had deficits on all cognitive measures compared with both control groups. In contrast, children with later onset differed from the normative population only on VIQ and the acquired knowledge factor. In multiple regression analyses, duration of disease and indexes of liver dysfunction combine to predict cognitive scores. These preliminary findings suggest that children with early onset of liver disease are at high risk for cognitive impairment.

Biliary Atresia↗
PubMed1991

Crystallization and preliminary X-ray studies of annexin IV (endonexin), a calcium-dependent phospholipid-binding protein.

Annexin IV (endonexin) has been purified from chicken liver and crystallized by the vapour diffusion method. Crystals which diffract to at least 2.2 A have been obtained. They belong to space group R3 and have unit cell dimensions of a = b = 99.4 A, c = 96.2 A, alpha = 90 degrees, beta = 90 degrees, gamma = 120 degrees. There is one molecule of 32,500 Da per asymmetric unit.

Animals↗
PubMed1991

Emotional adaptation in children after liver transplantation.

The emotional adaptation of 25 children who had undergone successful liver transplantation at least 1 year previously was evaluated and compared with that of a control group of 26 children with diabetes mellitus, matched for age, gender, and socioeconomic status, and with reported normative values. With the use of parent- and self-report measures, emotional adaptation was assessed in terms of behavioral adjustment (Child Behavior Checklist), depressive experiences (Children's Depression Inventory), anxiety (State-Trait Anxiety Inventory for Children), and self-concept (Piers-Harris Children's Self-concept Scale). Similar variables were also assessed by a projective personality measure (Rorschach). We found minimal differences in emotional adjustment between liver transplant and diabetic groups; on self-report measures, the adjustment of those with liver transplants was as good as, or better than, that of normative samples. However, on other tests, children with transplants differed from normative samples. On projective measures, liver transplant recipients had an increased number of depressive experiences, situationally related internal distress, and a greater tendency toward negative self-focus and evaluation. We conclude that in pediatric liver transplant recipients, behavioral and emotional adjustment is as good as in children with another chronic illness; in comparison with physically well children, the transplant recipients have subtle signs of emotional difficulties.

Adaptation, Psychological↗
PubMed1991

Computed tomography in the pre-operative assessment of mediastinal tumours--does it improve surgical management?

Computed tomography (CT) provides detailed imaging of the mediastinum. To assess whether this information improves subsequent surgical management 39 consecutive cases were reviewed. 21 patients had pre-operative CT of the mediastinum (CT group); 18 did not (No-CT group). The pre-operative use of CT resulted in the correct assessment of tumour consistency in 20 patients, the correct extent of invasion in 16, and the correct diagnosis in 10. In 15 of the 39 cases the surgical management was inappropriate because exploration was performed for an inoperable tumour, where no tumour was found, or when nonsurgical treatment was indicated. The number of inappropriate procedures was significantly lower in the CT group. These results suggest that the routine use of CT in the assessment of mediastinal tumours is justified by a subsequent improvement in surgical management.

Adult↗
PubMed1991

Neuropsychological outcome of pediatric liver transplantation.

Children with end-stage liver disease who undergo liver transplantation may have unrecognized neuropsychological and academic deficits, for which remediation programs may be available. Intellectual, academic, and neuropsychological measures of 28 pediatric patients who had received successful liver transplantation at least 1 year previously were compared with those of 18 patients with cystic fibrosis (to control for effects of growth retardation and chronic illness) matched for age, age at diagnosis, physical growth, and parents' socioeconomic status. Liver transplant patients had significantly lower scores on nonverbal intelligence tests (mean +/- SD for liver transplant vs cystic fibrosis patients: 89.1 +/- 19.1 vs 105.8 +/- 17.6), lower academic achievement, and lower zeta scores for age in the areas of learning and memory (-0.68 +/- 1.09 vs 0.19 +/- 1.24), abstraction and concept formation (-1.73 +/- 1.58 vs -0.79 +/- 1.37), visual-spatial function (-0.66 +/- 1.09 vs 0.10 +/- 0.69), and motor function (-0.13 +/- 0.85 vs 0.36 +/- 0.57). No differences were found on tests of verbal intelligence, or in alertness and concentration, perceptual-motor, and sensory-perceptual areas. Cyclosporine levels were found to correlate positively with motor speed (r = .41, P less than .05). Thorough psycho-educational and neuropsychological evaluations should be considered for pediatric patients who receive liver transplantation to allow these children to maximize their potential.

Adolescent↗
PubMed1990

Refinement of a partially oxygenated T state human haemoglobin at 1.5 A resolution.

The degree of ligation of T state human haemoglobin crystals is reduced by inositol hexaphosphate (IHP). The structure of a partially ligated haemoglobin has been refined using fast Fourier restrained-least-squares techniques. Manual interventions were required to escape from local minima and introduce a large number of solvent molecules. Individual isotropic temperature factors were refined for all atoms and the final average atomic temperature factor is 32.3 A2. The final R factor is 19.6% for all data between 10 and 1.5 A. The final model consists of 4560 protein atoms and 313 solvent molecules. The occupancies of the ligand atoms and the anisotropic behaviour of the iron atoms have been refined, demonstrating that the alpha haem groups are only partially ligated and that there is no ligation of the beta haems. Density for the IHP indicates that it is not well ordered even though changes in the ligation and structure of the haemoglobin indicate its presence.

Fourier Analysis↗
PubMed1990

Crystallization of the rainbow trout (Salmo gairdneri) haemoglobin IV.

Crystals of rainbow trout (Salmo gairdneri) haemoglobin IV were grown in mini batches from a solution of ammonium sulphate. Large single crystals grew over five days and were up to 2 mm in length. X-ray diffraction experiments indicated a space group of C222(1) with unit cell dimensions of a = 85.3 A, b = 94.6 A and c = 105.7 A. The crystals diffract to better than 2.5 A but exhibit some mosaicity along the c axis.

Animals↗
PubMed1990

Primary bone tumours of the thoracic skeleton: an audit of the Leeds regional bone tumour registry.

An audit of the Leeds regional bone tumour registry found that primary bone tumours of the thoracic skeleton constituted 90 of the 2004 cases (4.5%). Thirty seven per cent occurred in the ribs, 32% in the scapulae, 11% in the thoracic vertebrae, 11% in the sternum, and 9% in the clavicles. Malignant tumours were more common than benign (54 v 36) and occurred in an older population (mean ages 47 and 31 years). The scapula was the most common site for malignant lesions and the ribs the most common site for benign tumours. Chondrosarcoma was the commonest tumour in older patients, fibrous dysplasia and plasmacytoma in the middle age group, and eosinophilic granuloma in children. Presenting symptoms were a poor guide to whether the lesion was malignant or not. This and the small proportion of correct preoperative diagnoses indicate the need for early biopsy. Bone tumour registries provide a valuable source of cumulative information about uncommon tumours and facilitate accurate diagnosis, teaching, and research.

Adolescent↗
PubMed1990

Identifying factors in post-operative successful adaptation to pediatric liver transplantation.

In order to identify variables contributing to successful adaptation to liver transplantation, 38 families, at least six months post-transplant, were divided according to transplant team members' rating into two groups: those with successful adaptation to transplant and those families at risk for difficulties. Families who had successful follow-up periods tended to be characterized by intact marriages, private insurance coverage, less subjective financial stress, and higher intellectual and developmental functioning in the child. Single-parent families who had no pre-evaluation involvement with liver transplant organizations and had lengthy post-operative hospital stays more frequently had complications post-transplant. Case studies are presented illustrating the application of this information.

Adaptation, Psychological↗
PubMed1989

Mental and motor development, social competence, and growth one year after successful pediatric liver transplantation.

We measured intellectual and motor function, social competence, and growth in 29 children (mean age 4 years 7 months) before liver transplantation and 1 year later. We used either the Bayley Scales, the Stanford-Binet Intelligence Scale, and the Minnesota Child Development Inventory (MCDI), Motor Age Quotient, or the Wechsler Scales, depending on the age of the child at testing. Social function was measured with the MCDI or the Child Behavior Checklist. All anthropometric measures were expressed relative to normal values for age and sex. Patients whose intellectual and motor scores were less than 80 before transplantation gained an average of 8 points, but these changes were not statistically significant, nor were the changes on these measures for the group as a whole. The development of children with onset of liver disease in the first year of life was more likely to remain delayed after transplantation. Older subjects improved significantly in social competence (p less than 0.008). There were significant increments after transplantation in weight, head circumference, and arm anthropometrics (p less than 0.0001 to 0.04), but there was no change in linear growth rate. Increments in length correlated negatively with steroid dosage, and change in head circumference was associated with age at time of transplantation (p less than 0.005 to 0.10).

Adolescent↗