Biomedical subjects

R Butterfield

Publications and source records attributed to R Butterfield.

5 recordsLinked to original sources

PubMed2001

The role of surveillance magnetic resonance imaging (MRI) scanning in detecting recurrent brain tumors in asymptomatic children.

BACKGROUND: There is controversy regarding the utility of routine surveillance scanning for asymptomatic children with brain tumors. Although the role of CT or magnetic resonance imaging (MRI) scanning in this setting has been examined in several studies, none have focused on children followed exclusively by MRI. The purpose of this study was to determine how often recurrent brain tumors are detected by routine MRI surveillance in asymptomatic children. METHODS: The medical records of all children with brain tumors treated at Children's Hospital at Strong from 1990-1999 were reviewed. Recurrence was defined as an increase in size of the tumor on MRI scan. Astrocytomas and gangliogliomas were classified as low-grade tumors; high-grade astrocytomas, medulloblastomas, and ependymomas were classified as high-grade tumors. RESULTS: Of the 112 evaluable children with brain tumors during this time period, 46 (41%) suffered an MRI-documented recurrence. Of these 46 patients, 13 (28%) had low-grade tumors and 33 (72%) had high-grade tumors. Twenty-seven of the 46 recurrences (59%) occurred in asymptomatic children. Ten of the 13 children (77%) with recurrent low-grade tumors were asymptomatic compared to 17 of 33 children (52%) with recurrent high-grade tumors (p = 0.18). The median survival from time of recurrence for the symptomatic children was seven months, while the median survival from time of recurrence for the asymptomatic children has not yet been reached (p = 0.025). When the analysis was confined to children with high-grade tumors, there was no difference in median survival from the time of recurrence for symptomatic versus asymptomatic children (5 mo. versus 7 mo.) (p = 0.25). The frequency of detection of recurrences by surveillance scanning in asymptomatic children was 4.2% (one recurrence detected per 24 surveillence MRI scans). CONCLUSION: The majority of recurrent brain tumors are detected by MRI surveillence in asymptomatic children. However, asymptomatic recurrences were detected in only a small proportion of surveillance scans and had no impact on survival in children with high-grade tumors.

Adolescent↗

PubMed2000

Factor analysis of three standardized tests of memory in a clinical population.

OBJECTIVES: The aim of this study was to determine the factor structure of three standardized memory tests: Wechsler Memory Scale-Revised (WMS-R), Warrington Recognition Memory Test (WRMT), Doors and People Test (D&P). We investigated whether these different standardized tests of memory are consistent in their evaluation of memory function, and the extent to which these tests discriminate between different memory functions (e.g. recall/recognition and verbal/non-verbal memory). DESIGN: Fifty patients with selective memory impairment were tested on the WMS-R, WRMT and D&P. METHODS: Age-scaled scores from selective measures of these tests (WMS-R-verbal, WMS-R-visual, WMS-R-delay, WRMT-words, WRMT-faces, D&P-people, D&P-doors, D&P-shapes, D&P-names) were used as input to a factor analysis. RESULTS: Maximum likelihood factor analysis yielded a three-factor solution consistent with a theoretically motivated fractionation of memory function into recall and recognition components. Recognition performance, but not recall performance, showed dissociation into visual and verbal components. CONCLUSIONS: The WMS-R, WRMT and D&P are highly consistent in their assessment of memory function. The results of the factor analysis are consistent with a theoretically motivated fractionation of recall and recognition memory. They are also partially consistent with a dissociation between visual and verbal memory function.

Adolescent↗

PubMed1981

A precision pump for simulated cardiographic studies.

A system simulating physiologic and pathologic changes in left-ventricular volume is presented. Its purpose is to provide a model to establish the accuracy of current equipment for assessing a heart's performance where the actual volume and size are measurable. The versatility of the model allows a wide range of variability of various parameters for simulation of many clinical situations.

Cardiac Output↗

PubMed1976

Clinical and subclinical vitamin D deficiency in Bradford children.

A survey of the vitamin D status of Bradford schoolchildren was carried out in April 1973, employing conventional biochemistry, radiology, and measurement of 25-hydroxycholecalciferol levels. Biochemical evidence of rickets was present in 45% of the Asians. When re-examined in September, several children showed spontaneous biochemical resolution; nevertheless, radiological abnormalities were present in 12% of the original sample. No evidence of rickets was detected in the smaller White sample. Minor biochemical abnormalities were present in 9 of the 40 West Indian children. A study of admissions of Bradford hospitals in the 4 years 1969-1972 inclusive confirmed that clinical vitamin D deficiency was confined to Asians except for a few cases of infantile rickets in White children. The probability that one Asian child in 40 may require admission during the period from birth to adolescence emphasizes the urgent need for the introduction of prophylactic measures.

Adolescent↗

PubMedDate not supplied

Metabolism of insulin in erythrocytes from renal failure patients on maintenance hemodialysis.

Glucose tolerance does not improve to the normal level after dialysis; however, our studies showed that the insulin receptor binding to erythrocytes of nondiabetic patients with chronic renal failure (CRF) on hemodialysis was more than that in normal subjects. To understand this apparent anomaly in insulin receptor action and glucose metabolism, we investigated insulin degradation-a postreceptor event of insulin binding-in erythrocytes from CRF patients and compared it with that of normal subjects. We studied insulin degradation by erythrocytes from each of eight CRF patients and five normal subjects. The average hyperbolic insulin degradation curve for the CRF patients showed lower activity and a right-handed shift compared to the curve for the normal subjects. The average maximum degradation of insulin in the CRF patients was significantly lower than that of normal subjects. The number of erythrocytes required to produce 50% of maximum insulin degradation was significantly greater in these patients than that in the normal subjects. Furthermore, a linear correlation was observed between the duration of dialysis and maximum percent of insulin degradation in the CRF patients. Clinical implications of these findings are unclear at the present time. However, the insulin-degrading activity in erythrocytes may be reflective of that in other body tissues.

Adult↗