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Biomedical subjects

B D Moore

Publications and source records attributed to B D Moore.

At least 37 records · Page 2Linked to original sources
PubMed1995

Efficacy of growth hormone replacement therapy in children with organic growth hormone deficiency after cranial irradiation.

We evaluated the growth response of 20 childhood cancer survivors who received growth hormone (GH) replacement therapy (0.3 mg/kg/week) for at least 12 months. In all subjects, GH deficiency was associated with cranial irradiation and was documented with growth charts, bone age, and somatomedin C levels; at least one GH stimulation test was available for 14 children. Pretreatment overall growth velocity was 3.3 +/- 0.5 cm/year (mean +/- SE) over a 3-year period. After GH replacement, growth velocity was 8.6 +/- 0.6 cm/year during the first year (n = 20), 7.2 +/- 0.5 cm/year during the second year (n = 17), 5.9 +/- 0.6 cm/year during the third year (n = 11), and (6.1 +/- 0.6 cm/year during the fourth year (n = 7). Growth response, tabulated by age at onset of GH replacement, was compared with the response in GH-naive children with idiopathic GH deficiency (data obtained through the Genentech Inc. National Cooperative Growth Study Summary, September 1991); the growth velocity fell within the range described for idiopathic GH deficiency adjusted for either chronological or bone age. We conclude that children with GH deficiency after cranial irradiation for neoplastic diseases respond to GH replacement therapy as well as children with idiopathic GH deficiency.

Adolescent↗
PubMed1994

'Organic phase buffers' control biocatalyst activity independent of initial aqueous pH.

Combinations of triisooctylamine with its hydrochloride, or of triphenylacetic acid with its Na+ salt, can function as buffers for use during biocatalysis in organic media. They can control the pH of an adjacent aqueous phase, even though both forms of each buffer remain in the organic phase. With 0.1 M aqueous NaCl, the mid-point pH values obtained with the two buffer systems are around pH 4.5 and 7.0, respectively. The activity of an immobilized subtilisin Carlsberg shows a strong dependence on the ratio of the two forms of the triphenylacetic acid buffer system. Without the buffer, the rate shows the normal dependence on the pH of the aqueous solution before drying; however, this is almost eliminated if the buffer is used. The amine buffer system can similarly affect the activity of an immobilized Rhizomucor miehei lipase.

Buffers↗
PubMed1994

Neuropsychological changes in children with cancer: the treatment of missing data in longitudinal studies.

Researchers conducting longitudinal studies with children or adults are inevitably confronted with problems of attrition and missing data. Missing data in longitudinal studies is frequently handled by excluding from analyses those cases for whom data are incomplete. This approach to missing data is not optimal. On the one hand, if data are missing at random, then dropping incomplete cases ignores information collected on those cases that could be used to improve estimates of population parameters (e.g., means, variances, covariances, and growth rates) and improve the power of significance tests of statistical hypotheses. On the other hand, if data are not missing at random, then dropping incomplete cases leads to biased parameter estimates and hypothesis tests that may be internally and externally invalid. This study uses three years of follow-up data from a longitudinal investigation of neuropsychological outcomes of cancer in children to demonstrate the problems presented by missing data in repeated measures designs and some solutions. In evaluating potential biasing effects of attrition, the study extends previous research on neuropsychological outcomes in pediatric cancer by inclusion of patients whose disease had relapsed, and by comparison of surviving and nonsurviving patients. Although the data presented have specific relevance to the study of neuropsychological outcome in pediatric cancer, the problems of missing data and the solutions presented are relevant to a wide variety of diseases and conditions of interest to researchers in child and adult neuropsychology.

Adolescent↗
PubMed1994

Pediatric cataracts--diagnosis and treatment.

This paper discusses the causes and treatment of congenital and acquired cataracts in children. Although congenital cataracts are relatively uncommon, they are one of the leading causes of serious visual impairment in neonates. Successful visual rehabilitation of these patients is predicted on prompt diagnosis and surgical and optical intervention. The issue of deprivation amblyopia and the critical period of visual development are integral to their effective treatment. Acquired cataracts are more common than congenital cataracts. They are usually easier to treat because vision developed before the formation of the cataract and deprivation amblyopia is not present. The treatment of pediatric cataracts is made more complicated than cataracts in adults because of the growth and development of the eye and the inevitable necessity of treating amblyopia.

Amblyopia↗
PubMed1994

Lacrimal system abnormalities.

This report outlines several of the more important abnormalities of the lacrimal system in infants and young children. Although rare, alacrima can be a very difficult clinical problem to treat. The most common cause of alacrima is the Riley-Day syndrome. Nasolacrimal duct obstruction is a very common anomaly in children. The clinical appearance and treatment of this disorder are discussed.

Child↗
PubMed1994

Neuropsychological profile of children with neurofibromatosis, brain tumor, or both.

Neurofibromatosis type 1, a common autosomal dominant genetic disorder, is associated with numerous physical and medical anomalies as well as an increased incidence of learning disability. Tumors of the central nervous system have been estimated to occur in 15%, but their contribution to neuropsychological status is unknown. This study examines the relative contribution of neurofibromatosis and brain tumor to the cognitive profile of children with neurofibromatosis. A comprehensive battery of neuropsychological and behavioral tests was administered to a group of 65 children with neurofibromatosis type 1. Fourteen were then matched on demographic variables with two other groups of children who had either a brain tumor in addition to neurofibromatosis or a brain tumor alone. The two brain tumor groups were also matched on tumor type, location, and therapy. Mean scores of the neurofibromatosis-brain tumor group were generally the lowest of the three groups; those of the brain tumor group were highest, and performance of the neurofibromatosis group was generally between the other two groups. These results suggest that neurofibromatosis is, by itself, associated with significant cognitive morbidity, but that the severity of the problems is increased somewhat if a brain tumor is also present.

Adolescent↗
PubMed1994

Postoperative mutism in neurosurgery. Report of two cases.

Mutism is defined as a state in which a patient is conscious but unwilling or unable to speak. It has been reported to occur in association with a multitude of conditions, including trauma, epilepsy, tumors, stroke, psychoses, and brain surgery. The cases of two patients who became mute in the immediate postoperative period are presented. The first patient developed mutism following removal of a parasagittal meningioma, and the second following removal of a posterior fossa medulloblastoma. It is believed that transient injury may have occurred to the supplementary motor cortex in the first case and to the dentate nuclei in the second case. It is interesting that these two areas are connected via pathways involving the ventrolateral nucleus of the thalamus, and that lesions of this thalamic nucleus can also lead to mutism. It therefore appears plausible that interruption of these pathways may be involved in the pathogenesis of mutism. Although mutism is an infrequent complication of brain surgery, neurosurgeons should be aware that it may occur following removal of lesions in these areas and that it is generally a transient condition.

Brain Neoplasms↗
PubMed1994

Optometric management of congenital cataracts.

BACKGROUND: Congenital cataracts have historically been a major cause of visual impairment in children. Their treatment improved once deprivation amblyopia became better understood. Many children born with congenital cataracts are now able to develop good functional levels of visual acuity. Early detection and surgical removal of the cataracts are only the first steps in the treatment. RESULTS: The optical correction of the resulting aphakia, usually with contact lenses, and the long term treatment of amblyopia when required are invariably more difficult. The pediatric optometrist is particularly well suited to manage this postsurgical treatment of patients with congenital cataracts.

Amblyopia↗
PubMed1992

Neurophysiological basis of cognitive deficits in long-term survivors of childhood cancer.

Thirty-three survivors of childhood cancer were tested with event-related potentials (P300), motor reaction time tests, and neuropsychological tests to assess the underlying physiological basis of treatment-related cognitive sequelae. Thirteen patients had received intrathecal chemotherapy, 11 had received intrathecal chemotherapy plus cranial radiotherapy, and nine had been treated without any form of central nervous system therapy. Neuropsychological performance of the groups treated without cranial radiotherapy was normal, but the group given cranial radiotherapy was significantly impaired. Mean reaction time and P300 latency were somewhat slower in the group given intrathecal chemotherapy relative to the group given no central nervous system treatment, but were significantly delayed in the group given cranial radiotherapy. Correlations of reaction time and P300 latency with neuropsychological test scores were also obtained. Results suggest that slowing of cortical activity secondary to white-matter damage may underlie cognitive decline in children treated with intensive central nervous system therapies, especially cranial radiotherapy.

Adolescent↗
PubMed1992

Dichotic listening in aphasics: response to Niccum and Speaks.

Since the dichotic listening technique was first described (Broadbent, 1954; Kimura, 1961), researchers have been interested in its ability to document hemispheric dominance for language and other functions in a noninvasive fashion. Numerous articles have been published using normal healthy subjects as well as others using patients who have suffered neurological disease or damage. Much controversy has been generated over the use of dichotic listening in the latter population, however, since unilateral brain lesions might be expected to alter normal perception. This paper responds to one recently published by Niccum and Speaks (1991) that attempted to explain why a lesion effect, and not hemispheric reorganization, is the best explanation for findings of left-ear advantage in recovering aphasics.

Aphasia↗
PubMed1992

Identification and levels of 2'-carboxyarabinitol in leaves.

2'-Carboxyarabinitol 1-phosphate (CA1P) is a naturally occurring inhibitor of ribulose-1,5 bisphosphate carboxylase/oxygenase activity. A chloroplast phosphatase has previously been identified that degrades CA1P in vitro to carboxyarabinitol (CA) plus phosphate, but CA has not yet been detected in plants. Here, we detail procedures to isolate and assay CA from leaves and utilize mass spectrometry to demonstrate for the first time that CA is present in plants. CA was present in leaves of all 13 species examined, including those of C(3), C(4), and Crassulacean acid metabolism photosynthetic subgroups. CA was present both in species with high levels of CA1P (e.g. Phaseolus vulgaris, Lycopersicon esculentum, Beta vulgaris) as well as in species with low levels of CA1P (e.g. Spinacea oleracea, Triticum aestivum). CA levels in the light were sometimes greater than those in the dark. Bean leaves had the most CA of any species tested, with levels in the light approaching 1 micromole per milligram of chlorophyll. In illuminated bean leaves, about 63% of the CA is located outside the chloroplast. CA is one of only a few branched chain sugar acids to be identified from plants.

Journal Article↗
PubMed1992

Metabolism of 2'-carboxyarabinitol in leaves.

Results presented here indicate that 2'-carboxyarabinitol (CA) is the in vivo precursor and product of 2'-carboxyarabinitol 1-phosphate (CA1P) metabolism in leaves. When [2-(14)C]CA was fed in the light to leaves of five species known to be highly active in CA1P metabolism (Phaseolus vulgaris, Lycopersicon esculentum, Helianthus annuus, Petunia hybrida, and Beta vulgaris), [(14)C]CA1P was formed in the dark. Reillumination of a Phaseolus leaf caused this [(14)C]CA1P to be rapidly metabolized to [(14)C]CA (t((1/2)) = 1 min). The epimer 2'-carboxyribitol could not substitute for CA in the dark synthesis of CA1P, and CA in the anionic form was a better substrate than CA in the lactone form. In leaves of Phaseolus vulgaris, the active CA pool size used in the dark synthesis of CA1P is between about 70 and 110 nanomoles per milligram of chlorophyll. The photosynthetic electron transport inhibitor diuron did not affect the dark synthesis of [(14)C]CA1P, but did greatly reduce the rate of its subsequent light degradation (t((1/2)) = approximately 10 min). Dark synthesis of [(14)C]CA1P was inhibited by dithiothreitol and NaF. From the present data, we suggest that CA1P and CA participate in a metabolic substrate cycle in vivo.

Journal Article↗
PubMed1992

Improved neuropsychological outcome in children with brain tumors diagnosed during infancy and treated without cranial irradiation.

Neuropsychological outcome of 28 patients with brain tumors diagnosed before the age of 36 months (mean, 19 months) was assessed using a comprehensive battery of tests. Elapsed time between diagnosis and testing averaged 6.2 years. Half the patients had received cranial radiation therapy and surgery, with and without chemotherapy, whereas the rest had received only surgery, with or without chemotherapy. Groups were comparable with respect to tumor diagnosis and location, age at diagnosis, race, and sex. Intellectual functioning was significantly lower in children whose treatment included cranial irradiation than in those treated without cranial irradiation, and this effect was more pronounced in nonverbal than in verbal intellectual abilities. Mean scores for the radiation group were lower than for the no-radiation group in all areas assessed and were significantly below age-based normative means in five of the eight cognitive areas: intellectual, memory, attention, motor, and visual-spatial skills. Mean scores for children in the no-radiation group were generally within the average range in all cognitive areas except visual-spatial skills, which were significantly below age-based normative means. Endocrine deficiencies and growth retardation were much more prevalent in patients treated with cranial irradiation. Because the immature brain is susceptible to treatment-related pathologic changes, infants are at greater risk than older children for significant, long-term neuropsychological, endocrine, and growth sequelae. In children treated without cranial irradiation, morbidity was minimized without an increased rate of mortality.

Brain↗
PubMed1991

Measurement of 2-carboxyarabinitol 1-phosphate in plant leaves by isotope dilution.

The level of 2-carboxyarabinitol 1-phosphate (CA1P) in leaves of 12 species was determined by an isotope dilution assay. (14)C-labeled standard was synthesized from [2-(14)C]carboxyarabinitol 1,5-bisphosphate using acid phosphatase, and was added at the initial point of leaf extraction. Leaf CA1P was purified and its specific activity determined. CA1P was found in dark-treated leaves of all species examined, including spinach (Spinacea oleracea), wheat (Triticum aestivum), Arabidopsis thaliana, and maize (Zea mays). The highest amounts were found in bean (Phaseolus vulgaris) and petunia (Petunia hybrida), which had 1.5 to 1.8 moles CA1P per mole ribulose 1,5-bisphosphate carboxylase catalytic sites. Most species had intermediate amounts of CA1P (0.2 to 0.8 mole CA1P per mole catalytic sites). Such intermediate to high levels of CA1P support the hypothesis that CA1P functions in many species as a light-dependent regulator of ribulose 1,5-bisphosphate carboxylase activity and whole leaf photosynthetic CO(2) assimilation. However, CA1P levels in spinach, wheat, and A. thaliana were particularly low (less than 0.09 mole CA1P per mole catalytic sites). In such species, CA1P does not likely have a significant role in regulating ribulose 1,5-bisphosphate carboxylase activity, but could have a different physiological role.

Journal Article↗
PubMed1990

Pretreatment neuropsychological status and associated factors in children with primary brain tumors.

We report on the neuropsychological status of 31 children with primary brain tumors who underwent assessment before receiving therapy. Overall, the children performed within normal limits in all test areas. The exception was the group with anterior hemispheric tumors who demonstrated deficits in executive cognitive functions. Also, when compared according to tumor type, children with midline tumors and hydrocephalus performed more poorly than others on measures of intelligence, executive abilities, visual-motor skills, and fine-motor functions. Although one-half to two-thirds of the children with supratentorial midline and infratentorial tumors had cranial nerve, oculomotor, or cerebellar deficits, only the latter were associated with specific neuropsychological deficits (poorer performance on fine-motor and visual-motor tests). Age did not appear to be a factor in these children's neuropsychological test performances.

Adolescent↗
PubMed1989

Photosynthetic Plasticity in Flaveria brownii: Growth Irradiance and the Expression of C(4) Photosynthesis.

Photosynthesis was examined in leaves of Flaveria brownii A. M. Powell, grown under either 14% or 100% full sunlight. In leaves of high light grown plants, the CO(2) compensation point and the inhibition of photosynthesis by 21% O(2) were significantly lower, while activities of ribulose 1,5-bisphosphate carboxylase/oxygenase and various C(4) cycle enzymes were considerably higher than those in leaves grown in low light. Both the CO(2) compensation point and the degree of O(2) inhibition of apparent photosynthesis were relatively insensitive to the light intensity used during measurements with plants from either growth conditions. Partitioning of atmospheric CO(2) between Rubisco of the C(3) pathway and phosphoenolpyruvate carboxylase of the C(4) cycle was determined by exposing leaves to (14)CO(2) for 3 to 16 seconds, and extrapolating the labeling curves of initial products to zero time. Results indicated that approximately 94% of the CO(2) was fixed by the C(4) cycle in high light grown plants, versus approximately 78% in low light grown plants. Thus, growth of F. brownii in high light increased the expressed level of C(4) photosynthesis. Consistent with the carbon partitioning patterns, photosynthetic enzyme activities (on a chlorophyll basis) in protoplasts from leaves of high light grown plants showed a more C(4)-like pattern of compartmentation. Pyruvate, Pi dikinase and phosphoenolpyruvate carboxylase were more enriched in the mesophyll cells, while NADP-malic enzyme and ribulose 1,5-bisphosphate carboxylase/oxygenase were relatively more abundant in the bundle sheath cells of high light than of low light grown plants. Thus, these results indicate that F. brownii has plasticity in its utilization of different pathways of carbon assimilation, depending on the light conditions during growth.

Journal Article↗
PubMed1989

Selective attention effects on somatosensory evoked potentials.

Short and long latency somatosensory evoked potentials (SEPs) to median nerve stimulation were recorded over the contralateral hemisphere. Simultaneously, signals evoked by the same stimulus were monitored at Erb's point. Recordings were made during three conditions which were presented in a different random order to each of the subjects tested. During the control condition the subjects were instructed to attend to and count the number of electrical pulses delivered to the median nerve of their right hand. During the two task conditions, in addition to the pulses, the subjects received stimulation on the dorsal surface of one of their hands. This consisted in drawing circles lightly for the duration of SEP recording using a cotton swab (Q-tip). During the trial, the Q-tip was momentarily withdrawn 15 to 20 times and the subject's task was to ignore the pulses, attend to this cutaneous stimulation and count the number of times the cutaneous stimulation was interrupted. SEPs to the pulse were significantly greater in amplitude when cutaneous stimulation was delivered to the same hand as the pulse (the right hand) than when it was delivered to the left hand. This effect was confined to the long-latency SEPs and did not appear in either the Erb's point response or the short latency SEPs. These data indicate that selective attention to peripheral stimulation is a relatively late process mediated by cortical mechanisms and argue against the notion of early suppression of irrelevant stimulus channels in subcortical centers or in the periphery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗