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Biomedical subjects

Anne Smith

Publications and source records attributed to Anne Smith.

9 recordsLinked to original sources

Speech movements do not scale by orofacial structure size.

The potential role of a size-scaling principle in orofacial movements for speech was examined by using between-group (adults vs. 5-yr-old children) as well as within-group correlational analyses. Movements of the lower lip and jaw were recorded during speech production, and anthropometric measures of orofacial structures were made. Adult women produced speech movements of equal amplitude and velocity to those of adult men. The children produced speech movement amplitudes equal to those of adults, but they had significantly lower peak velocities of orofacial movement. Thus we found no evidence supporting a size-scaling principle for orofacial speech movements. Young children have a relatively large-amplitude, low-velocity movement strategy for speech production compared with young adults. This strategy may reflect the need for more time to plan speech movement sequences and an increased reliance on sensory feedback as young children develop speech motor control processes.

Adult↗

Performance evaluation of the microPET R4 PET scanner for rodents.

The microPET R4 scanner is a dedicated positron emission tomograph (PET) for studies of rodents. A number of scanner parameters such as spatial resolution, sensitivity, scatter, and count rate performance were determined in this work, which showed that the microPET R4 is a suitable PET scanner for small animals like mice and rats. In the center of the field of view (FOV) a maximal sensitivity of 43.66 cps/kBq for a centered point source was calculated from a measurement with a germanium-68 line source within an energy widow of 250-750 keV. A spatial resolution of 1.85 mm full-width at half-maximum (FWHM) in the axial direction and 1.66 mm FWHM in the transaxial direction was measured in the center with a 1-mm-diameter sodium-22 point source. Within the inner 20 mm of the FOV the volumetric resolution is better than 15.6 micro l, corresponding to a linear resolution of less than 2.5 mm in all three dimensions. Images of a high-resolution phantom and from mice and rat studies illustrate the good performance of the scanner. A maximal noise equivalent count rate (NECR) was reached at 174 kcps for a mouse phantom and at 93 kcps for a rat phantom (energy window 250-750 keV). Scatter fractions were measured between 0.30 and 0.42 for an energy window of 250-750 keV and phantom diameters similar to mice and rats. A comparison with the microPET P4 model for primates illustrates the gain in sensitivity due to a smaller detector ring diameter but also the changes in NECR.

Animals↗

Development of neural processes mediating rhyme judgments: Phonological and orthographic interactions.

Development of neural processes underlying integration of phonological and orthographic information were assessed by measuring event-related brain potentials (ERPs), judgment accuracies and reaction times (RTs) in 20 children (9-10 years) and 20 adults performing visual rhyme judgments. Half the trials were phonologically and orthographically congruent across the prime-target pairs (e.g., thrown-own, cake-own), and half were incongruent (e.g., gown-own, cone-own). For both children and adults, behavioral performance was most affected when different phonological representations had to be encoded from similar orthographic representations (e.g., gown-own), and the amplitudes of the N350 reflected effects of both rhyme and phonological/orthographic congruency. Latencies of the N350 were shorter over the left hemisphere only in adults, and phonological/orthographic incongruence produced greater delays in children's processing. Therefore, it appears that neural systems mediating rhyming judgments develop early; however, adults exhibit increased efficiency for left-hemisphere processing and are less affected by interference from incongruent phonological and orthographic codes.

Adolescent↗

Novel Kaposi's sarcoma-associated herpesvirus homolog in baboons.

Kaposi's sarcoma (KS) and lymphoproliferative diseases induced by KS-associated herpesvirus (KSHV/human herpesvirus 8) cause substantial morbidity and mortality in human immunodeficiency virus-infected individuals. To understand KSHV biology it is useful to investigate closely related rhadinoviruses naturally occurring in nonhuman primates. Here we report evidence for a novel KSHV homolog in captive baboon species (Papio anubis and other). Using degenerate PCR we identified a novel rhadinovirus, PapRV2, that has substantial sequence identity to two essential KSHV genes, the viral polymerase and thymidylate synthase. A subset of animals exhibited detectable PapRV2 viral load in peripheral blood mononuclear cells. Extensive serological analysis of nearly 200 animals in the colony demonstrated that the majority carried cross-reacting antibodies that recognize KSHV or macaque rhadinovirus antigens. Seroreactivity increased with age, similar to the age-specific prevalence of KSHV in the human population. This establishes baboons as a novel resource to investigate rhadinovirus biology, which can be developed into an animal model system for KSHV-associated human diseases, vaccine development, and therapy evaluation.

Amino Acid Sequence↗

Randomized phase III study of fludarabine phosphate versus cyclophosphamide, vincristine, and prednisone in patients with recurrent low-grade non-Hodgkin's lymphoma previously treated with an alkylating agent or alkylator-containing regimen.

PURPOSE: To compare in a phase III study the safety and efficacy of fludarabine to that of cyclophosphamide, vincristine, and prednisone (CVP) in recurrent, low-grade, non-Hodgkin's lymphoma after previous response to systemic treatment. PATIENTS AND METHODS: Patients were randomized to fludarabine (25 mg/m(2) intravenously on days 1 to 5, every 28 days) or CVP (cyclophosphamide 750 mg/m(2) and vincristine 1.2 mg/m(2) both intravenously on day 1 and prednisone 40 mg/m(2) orally on days 1 to 5, every 21 days). The primary outcome assessed was progression-free survival (PFS); secondary outcomes included treatment-free survival (TFS), overall survival (OS), treatment-related toxicity, and quality of life (QoL) according to the European Organization for Research and Treatment of Cancer's Quality of Life Questionnaire C-30 version 1.0 instrument. RESULTS: Ninety-one patients were randomized, 47 to fludarabine and 44 to CVP. There was no difference in response rates, with 64% (complete response [CR], 9%) for fludarabine versus 52% (CR, 7%) for CVP (P =.72). With a median follow-up of 42 months, median PFS (11 months v 9.1 months; P =.03) and TFS (15 months v 11 months; P =.02) were superior in patients receiving fludarabine. No difference in median overall survival was detected (57 months for fludarabine v 44 months for CVP; P =.95). Three patients receiving fludarabine died of treatment-related toxicity compared with none of the patients receiving CVP. Peripheral neuropathy and alopecia were more common with CVP. Patients receiving fludarabine had higher scores for social function (P =.008); no other differences in QoL were detected. CONCLUSION: In recurrent low-grade lymphoma, fludarabine improves PFS, TFS, and social function scores in comparison with CVP but does not improve OS.

Adult↗

Developmental change in variability of lip muscle activity during speech.

Compared to adults, children's speech production measures sometimes show higher trial-to-trial variability in both kinematic and acoustic analyses. A reasonable hypothesis is that this variability reflects variations in neural drive to muscles as the developing system explores different solutions to achieving vocal tract goals. We investigated that hypothesis in the present study by analyzing EMG waveforms produced across repetitions of a phrase spoken by 7-year-olds, 12-year-olds, and young adults. The EMG waveforms recorded via surface electrodes at upper lip sites were clearly modulated in a consistent manner corresponding to lip closure for the bilabial consonants in the utterance. Thus we were able to analyze the amplitude envelope of the rectified EMG with a phrase-level variability index previously used with kinematic data. Both the 7- and 12-year-old children were significantly more variable on repeated productions than the young adults. These results support the idea that children are using varying combinations of muscle activity to achieve phonetic goals. Even at age 12 years, these children were not adult-like in their performance. These and earlier kinematic studies of the oral motor system suggest that children retain their flexibility, employing more degrees of freedom than adults, to dynamically control lip aperture during speech. This strategy is adaptive given the many neurophysiological and biomechanical changes that occur during the transition from adolescence to adulthood.

Adult↗

Articulatory movements in adolescents: evidence for protracted development of speech motor control processes.

In order to contribute to a more comprehensive model of speech motor development, we examined the movement trajectories of the upper lip, lower lip, and jaw to determine (a) if there are changes in articulatory motor control in late adolescence; (b) if there are sex differences during this developmental period, perhaps related to differences in craniofacial growth rates; (c) if control of jaw motion is adultlike earlier than control of the upper and lower lip; and (d) if control of spatial and temporal aspects of articulatory movement co-develop in adolescence. Participants were 12-, 14-, and 16-year-olds, and young adults (mean age 21.2 years), with 15 males and 15 females per group. A measure reflecting spatiotemporal consistency in trajectory formation for repeated productions of a phrase was calculated for the upper lip, lower lip, and jaw movements. Overall trajectory variability was higher for adolescents compared to young adults. Jaw trajectories were less variable than upper lip or lower lip trajectories, but all effectors showed parallel decreases in variability as age increased, suggesting that control of jaw movement does not reach adult performance before control of the lips. Separate temporal and spatial measures revealed that adolescents had significantly longer movement durations, lower velocities, smaller displacements, and greater variability on these measures than young adults. There were no sex differences on any measure examined, suggesting that peripheral growth factors do not account for this protracted developmental time course. These results provide initial evidence of significant changes in speech motor control processes during adolescence.

Adolescent↗

An incremental approach to educational development.

This article examines the implications for education in practice of the document. Preparation of Mentors and Teachers (ENB/DoH 2001), and the changes that it imposes on those who teach in the practice area. The range of academic and clinical skills practitioners require to teach and assess students at differing levels of professional practice is explored. The authors discuss the need to support teaching. Learning and assessing in the practice area from the pre-registration stage through to higher level practice. A flexible model of educational theory and practice that has the capacity to incorporate a clinical component is proposed.

Education, Nursing↗