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Biomedical subjects

R D Barr

Publications and source records attributed to R D Barr.

At least 37 records · Page 2Linked to original sources
PubMed1999

Health-related quality of life in survivors of tumours of the central nervous system in childhood--a preference-based approach to measurement in a cross-sectional study.

There is an evident need to measure the comprehensive burden of morbidity experienced by survivors of brain tumours in childhood. To this end, a questionnaire based on the Health Utilities Index mark 2 (HUI2) and mark 3 (HUI3) systems was completed independently for a cohort of such children by their parents, by a nurse, by physicians and by a selected group of the children themselves. Each of the HUI2 and HUI3 systems consists of a multi-attribute health status classification scheme linked to a preference function which provides utility scores for levels within single attributes (domains of health) and for global health states. All eligible families (n = 44) participated. Even cognitively impaired children of at least 9.5 years of age could complete the questionnaire. The greatest burden of morbidity, occurring in two-thirds of children, was in the attribute of cognition. Surprisingly, almost one-third of children experienced pain. Global health status was lowest in children who underwent radiotherapy before the age of 5 years and the corresponding utility scores were related inversely to the volume irradiated. Children with demonstrable disease had lower scores than those in whom disease was not evident. There was a high level of agreement (intraclass correlation coefficients > 0.5) on formal assessment of inter-rater reliability for global health-related quality of life utility scores. The usefulness of measures of health status and health-related quality of life, in children surviving brain tumours, has been demonstrated by this study.

Adolescent↗
PubMed1999

Applicability of the Health Utilities Index to a population of childhood survivors of central nervous system tumours in the U.K.

This paper describes the application of a multi-attribute, preference-linked health status and health-related quality of life measurement system--the Health Utilities Index (developed in Canada)--to a group of subjects in the U.K. Children who had survived tumours of the central nervous system (n = 30, age 6-16 years) formed the study group. Respondents (children, parents, physicians and physiotherapists) found the activity (completion of a 15-item questionnaire) to be acceptable and not burdensome (it was accomplished easily by all children > or = 10 years of age). Instrumental reliability was established by acceptable intra- and interobserver agreement and construct validity was supported by strong similarities between the results obtained in this study and those reported from a similar group of children in Canada. The greatest burden of morbidity was reported for the attributes of emotion and cognition (each affected in > 50% of the children). Pain was surprisingly prevalent (affected in approximately one-third of children). The finding of a large number of unique health states emphasises the complex morbidity burden experienced by these children who self-reported poorer overall health (as reflected in utility scores) than did the proxy respondents. The information obtained from this study is readily interpretable and clinically useful. The results of this study also illustrate that extreme caution must be exercised in undertaking linguistic modifications to established instruments for, in this instance, these resulted in a loss of the ability to detect the most severe emotional morbidity and reduced the comparability of results between studies. With this provision, the Health Utilities Index is evidently applicable in the U.K. and the original version has been recommended for use in brain tumour studies by the U.K. CCSG (the U.K. Children's Cancer Study Group).

Adolescent↗
PubMed1999

Assessment of health status and health-related quality of life in survivors of Hodgkin's disease in childhood.

Although the great majority of children with Hodgkin's disease survive with modern treatment strategies, the list of late sequelae is long, yet there is no published information on the comprehensive health status and health-related quality of life (HRQL) in this population. In the experience of a single institution, survivors of Hodgkin's disease in childhood were invited to self-report on their health status using a 15-item questionnaire connected to the Health Utilities Index, a series of multi-attribute health status classification systems that, in turn, are linked to preference functions which provide single-attribute and global utility scores for HRQL. The mean global utility score was 0.85 (on a 0 = dead to 1. 0 = perfect health scale), a figure less than that in survivors of acute lymphoblastic leukemia (ALL) but comparable to that in survivors of brain tumors (0.84) or extremely low birthweight (ELBW 0.82). The burden of morbidity is emphasized by the ratio of the numbers of health states per patient:0.67 for survivors of Hodgkin's disease, 0.66 for survivors of brain tumors, 0.39 for survivors of ELBW, 0.47 for survivors of high-risk ALL and 0.28 for survivors of standard-risk ALL. In Hodgkin's disease survivors, the attributes affected most commonly and severely were pain, cognition and emotion. This experience demands exploration of the health status and HRQL in a much larger cohort of such survivors, perhaps in the context of co-operative group studies.

Child↗
PubMed1999

Preliminary translation and cultural adaptation of Health Utilities Index questionnaires for application in Argentina.

Quality-of-life assessment is being used increasingly in clinical research. This is true particularly in the case of survivors of cancer in childhood, where improving survival rates have raised concern regarding the long-term effects of medical cure. Health-status assessment and quality-of-life instruments have been developed for the most part in the English language, thus necessitating their translation and cultural adaptation for use in non-English-speaking countries. Our purpose was to develop a set of Spanish-language questionnaires for application with a population of children with cancer in a tertiary-care center in Buenos Aires, Argentina. The Health Utilities Index (HUI), a conceptual framework for assessing health status, was chosen for this study. Three distinct questionnaires, based on the HUI, were used: a self-completed one for health professionals and teachers (15Q) to report assessments of children and 2 interviewer-administered ones, for child survivors (42Q) to report assessments about their own health status and parents (45Q) to report assessments about their children's health status. The original translations and reviews were accomplished with direct oversight by members of the HUI Group, to ensure conceptual equivalence. The instruments were then tested in Buenos Aires by application to staff of the hematology-oncology service, childhood cancer patients and the parents of childhood cancer patients. Several modifications were made based on these tests. We concluded that the translation and cultural adaptation of these instruments was adequate for use with the groups tested in a pilot survey of survivors of childhood cancer in Argentina.

Adolescent↗
PubMed1998

Blood lipid profiles in children with acute lymphoblastic leukemia.

BACKGROUND: Abnormal blood lipid profiles have been associated with cancer. The objective of this study was to investigate the frequency and clinical significance of altered lipid profiles in children with acute lymphoblastic leukemia (ALL), the most common form of malignant disease in this age group. METHODS: Fasting blood lipid profiles (cholesterol [C], triglycerides [TG], high density lipoprotein [HDL], low density lipoprotein, very low density lipoprotein, apolipoproteins A1 [apo A1] and B, and lipoprotein a [Lp(a)]) were obtained in 24 children with ALL at diagnosis, 16 children during consolidation therapy with L-asparaginase, and 18 children during maintenance therapy without L-asparaginase. For comparison the authors studied lipid profiles in 15 children previously treated for leukemia, 15 healthy control children, and 17 children with other forms of cancer, both localized and widespread. RESULTS: An altered blood lipid profile was observed at the time of diagnosis of ALL. Statistically significant values included elevated TG (1.82+/-1.23 mmol/L), reduced HDL-C (0.54+/-0.24 mmol/L), and reduced ApoA1 (0.77+/-0.18 g/L) levels. A wide range of Lp(a) levels (0-1990 mg/L) were observed. Significantly reduced HDL-C (0.55+/-0.20 mmol/L) and ApoA1 (0.69+/-0.22 g/L) were observed in children with widespread but not localized solid tumors at diagnosis. C and TG correlated with serum albumin levels. Significant therapy-related changes in lipid profiles were observed in children with ALL during combination therapy with L-asparaginase (extremely elevated TG levels [3.34+/-2.82 mmol/L] and a striking reduction in Lp(a) levels) that were not observed during combination therapy without L-asparaginase or in children during treatment for solid tumors. In this small study there was no relation between these abnormalities and either thromboembolic events or pancreatitis. Blood lipid profiles in children with ALL returned to normal on completion of therapy. CONCLUSIONS: The lipid abnormalities observed at diagnosis in children with widespread cancer (ALL or solid tumors) may reflect altered nutritional states or altered lipid metabolism. Reduced concentrations of Lp(a) and elevated TG levels suggest L-asparaginase specific alterations and may provide insight into the toxicity associated with this drug.

Antineoplastic Agents↗
PubMed1998

Impact of age and cranial irradiation on radiographic skeletal pathology in children with acute lymphoblastic leukemia.

BACKGROUND: Symptomatic osteopenia is a common form of morbidity in children with acute lymphoblastic leukemia (ALL) before, during, and after treatment. A causal role for corticosteroids has been proposed, but other investigators have suggested that cranial irradiation is an important factor contributing to this disorder. PROCEDURE: In this study of children with ALL, all of whom received steroids, skeletal morbidity was assessed radiographically by an observer who was blinded to the ages of the children, their risk categorization (and related treatment), and the timing of the assessments with respect to the administration of therapy. DISCUSSION: Skeletal morbidity was most prevalent in older subjects who had been given cranial radiotherapy. However, there was no difference in the frequency of fractures in two groups of younger children (< or = 9 years of age), one irradiated and the other not. CONCLUSIONS: It is likely that corticosteroid therapy plays an important part in the pathogenesis of this disorder. The role played by cranial irradiation is much less certain.

Age Factors↗
PubMed1998

Long-term gross motor performance following treatment for acute lymphoblastic leukemia.

BACKGROUND: The primary purpose of this descriptive study was to determine the long-term effects of cancer treatment in childhood on musculoskeletal function and gross motor skills. PROCEDURE: Musculoskeletal and gross motor function were assessed in a cohort of 36 survivors of acute lymphoblastic leukemia (ALL) seen in a pediatric tertiary care referral centre, compared to 36 age and gender matched comparison subjects. Basic gross motor skills were assessed using dimensions D: standing, and E: walking, running, and jumping of the Gross Motor Function Measure (GMFM). Strength, balance, and running speed and agility were assessed using the Bruininks-Oseretsky Test of Motor Proficiency (BOTMP). Hand grip strength and ankle dorsiflexion range of motion were also measured. Findings in the children with ALL were compared by dependent (paired) t-tests to those in age and gender matched children. RESULTS: The GMFM scores for standing were 98.7% and for walking, running, and jumping were 99% of normal. The mean standard scores for the BOTMP were significantly lower than those of the comparison group: strength 11.5 vs. 19.4, balance 9.4 vs. 15.5, and running speed and agility 9.9 vs. 16.6. The ALL subjects had less hand grip strength 156.3 vs. 190.2, and less ankle dorsiflexion 7.5 vs. 16.1 degrees than the comparison group. The survivors of childhood leukemia were able to perform most basic gross motor functions. However, musculoskeletal impairment was evident and levels of motor proficiency were significantly poorer than those of age and gender matched children. CONCLUSIONS: Programs to promote physical activity and limit disability may improve gross motor function and increase overall quality-of-life in survivors of leukemia in childhood.

Adolescent↗
PubMed1998

Binding of lithium and boron to human plasma proteins.

The binding of lithium and boron, at normal physiological levels, to plasma proteins has been investigated by the techniques of precipitation with ethyl alcohol and gel chromatography. Assays of lithium and boron were made by thermal neutron activation and mass spectrometric assay of 3He and 4He. Results of alcohol precipitation experiments for plasma from two apparently healthy donors showed that 13+/-4% and 16+/-3% of the lithium in plasma is protein bound, but essentially no boron is bound under the conditions used. We believe that because of denaturation of proteins which occurs during alcohol precipitation, these percentages represent lithium and boron tightly bound to protein molecules. The results of the gel-chromatography experiment, on the other hand, showed that lithium and boron are bound to a wide range of plasma proteins, from low (approximately 60,000 amu) to high (approximately 1,000,000 amu) molecular weights, and to very low- (approximately 6000 amu) molecular-weight ligands. Although a clear identification of the specific proteins which bind lithium and boron cannot be made at present, some possibilities can be suggested.

Blood Proteins↗
PubMed1998

Osteopenia in children surviving brain tumours.

Osteopenia has been reported in children surviving acute lymphoblastic leukaemia, apparently as a consequence of therapy. It has been suggested that cranial irradiation may play a crucial role in this disorder. To explore that possibility, survivors of brain tumours in childhood, all of whom had received radiotherapy, were examined for evidence of bone mineral loss. 19 children were assessed, on average at 7 years after treatment. Measurements of growth velocities, plain radiography of the skeleton, bone densitometry, health-related quality of life and physical activity were undertaken. Growth hormone (GH) deficiency had been detected in 6 children and 5 had received GH replacement, for a minimum of more than 3 years. 9 children were radiographically osteopenic (including the 5 who had received GH). Z scores for bone mineral density (BMD) were negative in the majority of children. Health-related quality of life was less and pain more frequent in those with low BMD scores. Pain was correlated negatively with both free-time activity and seasonal activity (P < 0.01). Osteopenia is a common sequel of therapy in children with brain tumours. Those with osteopenia have more pain and more compromised, health-related quality of life than those who are not osteopenic, and pain significantly limits physical activity. The pathogenesis of osteopenia in these children is still uncertain, but is likely to be multifactorial.

Adolescent↗
PubMed1998

Cardiac autonomic dysfunction in survivors of acute lymphoblastic leukemia in childhood.

The purpose of this study was to investigate autonomic regulation of neurocardiac function in survivors of acute lymphoblastic leukemia (ALL) in childhood, through power spectral and time domain analyses of the heart rate variability signal. Studies were conducted on 34 unselected patients and 34 age matched controls. Patients were in remission, off therapy for at least 20 months and from high risk (HR, n=21) and standard risk (SR, n=13) groups as described by Dana-Farber Cancer Institute protocols 87-01 and 91-01. Twenty-nine patients had received cranial irradiation, 7 on a hyperfractionated schedule. Power spectral analysis of the heart rate (PS/HRV) was performed on 30 min heart rate time series and time domain statistics were computed from 24 h Holter recordings. Left ventricular function was assessed by measuring ejection and shortening fractions on echocardiography. All such measures were normal. Analysis of PS/HRV revealed that the supine low frequency: high frequency (LF:HF) area ratio was elevated in patients compared to controls. Changes in the LF and HF power on standing were attenuated in the patients compared to controls. Circadian analysis revealed a depressed diurnal rhythm of heart rate in the patients. Those from the SR group showed greater reduction of the LF power response to orthostatic stress and a reduced circadian rhythm of the heart rate compared to those with HR ALL. Patients from the HR group showed reductions in both HF and LF power responses to orthostasis compared to controls. Elevated supine LF power and depressed circadian variation in the HF power band were evident only in female subjects. Patients who received standard cranial irradiation had higher LF:HF area ratio and diminished LF and HF power responses to orthostatic stress than did subjects in the hyperfractionated group. These findings suggest that the autonomic nervous regulation of the heart is compromised in patients treated for ALL in childhood even when resting echocardiographic measures provide no evidence of cardiac decompensation. The extent of neurocardiac dysfunction is influenced by risk status, gender and schedule of cranial irradiation.

Adolescent↗
PubMed1998

Bone and mineral abnormalities in childhood acute lymphoblastic leukemia: influence of disease, drugs and nutrition.

In children with acute lymphoblastic leukemia (ALL), abnormalities in mineral homeostasis and bone mass were first reported by our group in the late 1980s. Prospective longitudinal cohort studies in 40 consecutive patients receiving treatment according to the Dana-Farber Cancer Institute (DFCI) protocol 87-001 and 16 children receiving DFCI protocol 91-001 afforded us the opportunity to explore various etiologies of the observed abnormalities in mineral and bone metabolism, specifically the leukemic disease process and chemotherapeutic drugs such as steroids and aminoglycoside antibiotics. At diagnosis of ALL, > 70% of children had abnormally low plasma 1,25-dihydroxyvitamin D, 73% had low osteocalcin and 64% had hypercalciuria, indicating an effect of the leukemic process on vitamin D metabolism and bone turnover. During remission induction, treatment with high-dose steroid (prednisone or dexamethasone) resulted in further reduction in plasma osteocalcin and elevated parathyroid hormone levels. During 24 months of chemotherapy-maintained remission, reduction in bone mineral content (BMC), as measured by Z-scores, occurred in 64% of children, most severely affecting those > 11 years of age. A reduction in BMC during the first 6 months had a positive predictive value of 64% for subsequent fracture. By the end of 2 years of therapy, fractures occurred in 39% of children and radiographic evidence of osteopenia was found in 83% of the entire study group. Investigations of the biochemical basis of the bone abnormalities revealed that by 6 months hypomagnesemia developed in 84% of children (of whom 52% were hypermagnesuric) and plasma 1,25-dihydroxyvitamin D remained abnormally low in 70%. Altered magnesium status was attributed to renal wastage of magnesium following cyclical prednisone therapy and treatment with aminoglycoside antibiotics such as amikacin for fever accompanying neutropenia. Dietary intake and absorption of magnesium were normal. In 10 children treated for hypomagnesemia with supplemental magnesium for up to 16-20 weeks, plasma magnesium normalized in only 50% of subjects.

Adolescent↗
PubMed1998

Growth and body composition in response to chemotherapy in children with acute lymphoblastic leukemia.

Severely malnourished children afflicted by acute lymphoblastic leukemia (ALL), particularly in developing countries, have reduced tolerance to chemotherapy and a compromised prospect for survival. We investigated the prevalence and severity of alterations in growth and nutritional status in children with ALL from population-based referral areas in Canada. All children were treated with Dana-Farber Cancer Institute ALL Consortium protocols. First, the relative impact of cranial irradiation (CI) and chemotherapy on growth was studied in 116 children at diagnosis and at 6-month intervals during treatment. We observed a decline in height standard deviation (SD) score in the first year in all children, and a further decline in height SD score during the second year only in the children who received CI. Weight reduction occurred in the first year, but during the second year there was a disproportionate increase in weight compared with height, suggesting that children treated with ALL have a tendency toward obesity. Both chemotherapy and CI contribute to the altered growth observed in children treated for ALL. Second, intestinal functional integrity was assessed in 16 children during post-induction chemotherapy. Nutrient intake was adequate and there was minimal evidence of malabsorption: fat malabsorption occurred in only 1 child (after treatment-related pancreatitis), abnormal D-xylose absorption occurred in 2 children at 6 months of therapy (returning to normal 6 months later) and abnormal lactose absorption occurred in 4 children. Third, weight, height, whole body lean and fat mass measured by dual-energy X-ray absorptiometry and serum albumin were determined at diagnosis and at 6-month intervals throughout therapy in 19 children with ALL. Height SD scores decreased significantly during treatment. Serum albumin was abnormally low in 6/19 at diagnosis and 14/18 during intensive consolidation therapy. The mean change in the ratio of lean mass to total body weight showed a 5% reduction by 6 months of therapy. Body fat increased from a mean of 22% at diagnosis to 28% at completion of therapy. The majority of children treated for ALL thus have significant changes in nutritional status manifested by reductions in growth, alterations in lean and fat body mass and abnormally low serum proteins during intensive therapy.

Antineoplastic Agents↗
PubMed1997

Self-reported comprehensive health status of adult brain tumor patients using the Health Utilities Index.

BACKGROUND: The comprehensive health status of adult survivors of brain tumors is largely unexplored. METHODS: Using a multiattribute approach embodied in a 15-item self-assessment questionnaire, the overall burden of morbidity was measured in 50 brain tumor patients who were attending a neurooncology outpatient clinic. The comprehensive health status was accorded utility scores, and comparisons were made with health status measurements of the general population. RESULTS: The questionnaire was completed with ease by 90% of the respondents. Among the respondents, only 10% of the patients did not report some form of morbidity, and 80% reported multiple impairments. The most prevalent impairments occurred in the attributes of sensation, emotion, and cognition (in this predominantly ambulant group); each of these elements was limited in the majority of patients. A surprising finding was the self-report of pain by nearly 50% of the respondents. CONCLUSIONS: In this group of patients, the burden of morbidity and its complexity greatly exceeded that reported for the general population and were inadequately revealed by Karnofsky performance scores. The use of multiattribute health status measurement tools offers numerous advantages and should be employed in the routine clinical management of cancer patients.

Brain Neoplasms↗
PubMed1997

De novo mutation of the beta-globin gene initiation codon (ATG-->AAG) in a Northern European boy.

We present a case of beta-thalassemia intermedia involving a 13-year-old boy of Northern European descent. His mother, father and older sister have normal hematologic indices. Molecular studies demonstrate that the proband carries a novel mutation of the beta-globin gene initiation codon (ATG-->AAG) which should give rise to beta(0)-thalassemia trait. The possibility of non-paternity was excluded, indicating that the novel mutation was the result of a de novo event. A review of the literature indicates that mutations involving the beta-globin gene initiation codon can give rise to a more severe phenotype than is generally associated with most other beta(+) or beta(0) mutations.

Adolescent↗
PubMed1996

Altered mineral metabolism and bone mass in children during treatment for acute lymphoblastic leukemia.

Children with acute lymphoblastic leukemia (ALL) often develop bone pain, abnormal gait, and unusual fractures while in remission and receiving continuing chemotherapy. A prospective longitudinal cohort study was undertaken of bone mass and biochemical mineral status in 40 consecutive children (27 male, 13 female, aged 0.3-17.0 years) receiving therapy on the Dana-Farber Cancer Institute protocol 87-01. Radiography, lumbar spine dual-photon absorptiometry, and biochemical measurements of mineral status were performed at diagnosis and at 6-month intervals throughout 24 months of chemotherapy. Eleven patients were not completely evaluated (4 deaths and 7 off study). Radiographic evidence of osteopenia was observed in 10, 64, and 76% at diagnosis, 12 and 24 months, respectively. Fractures occurred in 39% of children during treatment. Reduction in bone mineral content (BMC), as measured by Z scores, occurred in 64% of patients and was most severe in those greater than 11 years of age at diagnosis. Reduction in BMC during the first 6 months of therapy had a positive predictive value of 64%, while an increase in BMC had a negative predictive value of 82% for subsequent fracture. By 6 months of therapy, 31/37 (84%) children were hypomagnesemic, of whom 16 (52%) were hypermagnesuric. Plasma osteocalcin was subnormal at diagnosis in 29/40 (73%) but increased to normal by 6 months of treatment. Vitamin D status was normal throughout, but plasma 1,25-dihydroxyvitamin D remained subnormal in greater than 70% of children. Urinary cross-link N-telopeptide was normal at diagnosis and became elevated in 58% of children by the end of therapy. Suppressed bone mineralization is evident at diagnosis in a minority of children with ALL. Skeletal morbidity and a reduction in bone mineral mass become more prevalent during treatment, with increased bone resorption, perhaps mainly as a consequence of corticosteroid administration.

Adolescent↗