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Biomedical subjects

D M Pearson

Publications and source records attributed to D M Pearson.

7 recordsLinked to original sources
PubMed2006

Small regions of overlapping deletions on 6q26 in human astrocytic tumours identified using chromosome 6 tile path array-CGH.

Deletions of chromosome 6 are a common abnormality in diverse human malignancies including astrocytic tumours, suggesting the presence of tumour suppressor genes (TSG). In order to help identify candidate TSGs, we have constructed a chromosome 6 tile path microarray. The array contains 1,780 clones (778 P1-derived artificial chromosome and 1,002 bacterial artificial chromosome) that cover 98.3% of the published chromosome 6 sequences. A total of 104 adult astrocytic tumours (10 diffuse astrocytomas, 30 anaplastic astrocytomas (AA), 64 glioblastomas (GB)) were analysed using this array. Single copy number change was successfully detected and the result was in general concordant with a microsatellite analysis. The pattern of copy number change was complex with multiple interstitial deletions/gains. However, a predominance of telomeric 6q deletions was seen. Two small common and overlapping regions of deletion at 6q26 were identified. One was 1,002 kb in size and contained PACRG and QKI, while the second was 199 kb and harbours a single gene, ARID1B. The data show that the chromosome 6 tile path array is useful in mapping copy number changes with high resolution and accuracy. We confirmed the high frequency of chromosome 6 deletions in AA and GB, and identified two novel commonly deleted regions that may harbour TSGs.

Astrocytoma↗
PubMed2001

The physical maps for sequencing human chromosomes 1, 6, 9, 10, 13, 20 and X.

We constructed maps for eight chromosomes (1, 6, 9, 10, 13, 20, X and (previously) 22), representing one-third of the genome, by building landmark maps, isolating bacterial clones and assembling contigs. By this approach, we could establish the long-range organization of the maps early in the project, and all contig extension, gap closure and problem-solving was simplified by containment within local regions. The maps currently represent more than 94% of the euchromatic (gene-containing) regions of these chromosomes in 176 contigs, and contain 96% of the chromosome-specific markers in the human gene map. By measuring the remaining gaps, we can assess chromosome length and coverage in sequenced clones.

Chromosomes, Human, Pair 1↗
PubMed2001

Animal models of schizophrenia: a critical review.

Current research into schizophrenia has remained highly fragmented, much like the clinical presentation of the disease itself. Differing theories as to the cause and progression of schizophrenia, as well as the heterogeneity of clinical symptoms, have made it difficult to develop a coherent framework suitable for animal modelling. However, a number of limited animal models have been developed to explore various causative theories and to test specific mechanistic hypotheses. Historically, these models have been based on the manipulation of neurotransmitter systems believed to be involved in schizophrenia. In recent years, the emphasis has shifted to targeting relevant brain regions in an attempt to explore potential etiologic hypotheses. The specific animal models developed within these frameworks are described in this review. Emphasis is placed on the critical evaluation of currently available models because these models help to shape the direction of future research.

Animals↗
PubMed1994

DNA sequence of the cut A, B and C genes, encoding the molybdenum containing hydroxylase carbon monoxide dehydrogenase, from Pseudomonas thermocarboxydovorans strain C2.

Pseudomonas thermocarboxydovorans strain C2 is capable of using carbon monoxide as the sole source of carbon and energy. The key enzyme for CO utilisation is the molybdenum containing iron-flavoprotein carbon monoxide dehydrogenase (CODH). This paper reports the DNA sequencing of a 4.7 kb region of the C2 genome which appears to encode the CODH enzyme. The genes for the three subunits of CODH, which we have named cut A, B and C, have been identified and they appear to form an operon. The predicted protein sequences of the three subunits have homology to the structurally related protein, xanthine dehydrogenase, from Drosophila melanogaster. By comparison with xanthine dehydrogenase it can be predicted that the molybdenum cofactor binds to the large subunit of CODH, the small subunit of CODH contains the iron-sulphur centers and the medium subunit binds FAD/NAD+.

Aldehyde Oxidoreductases↗
PubMed1990

Linguistic significance of babbling: evidence from a tracheostomized infant.

The role of babbling in language development is not well understood. One source of evidence is the utterances of infants who were tracheostomized during the period in which they would normally have produced syllabic vocalization. We describe here the phonetic patterns and linguistic development of a girl called Jenny. She was tracheostomized and generally aphonic from 0.5-1.8 but cognitively and socially normal, with near-normal comprehension of language. Acoustic analyses of Jenny's utterances following decannulation revealed a tenth of the canonical syllables which might be expected in normally developing infants, an extremely small inventory of consonant-like segments, and a marked preference for labial obstruents. In these ways, she resembled a group of infants of the same age who also cannot hear their oral-motor movements, the congenitally deaf, suggesting that the audibility of babbling contributes to its onset. Two months following decannulation, when Jenny was 1.10, she produced only a handful of different words. We think this is because aphonia prevented her from discovering the referential value of vocal expression and discouraged the formation of a phonetic repertoire that could be appropriated for lexical service. This unusual case suggests that babbling normally facilitates the development of language and speech.

Aphonia↗
PubMed1989

Verb finding in aphasia.

Word finding for nouns and verbs was examined in a heterogeneous group of aphasics (N = 9) by comparing the ability to generate synonyms and sentences for the same set of 20 nouns and 20 verbs. Synonym Generation performance resembled that of an age-matched group of normal control subjects (n = 9): In both groups, some subjects produced comparable numbers of synonyms for nouns and verbs while other subjects produced significantly fewer synonyms for verbs. Essentially the same two patterns were displayed on Sentence Generation using the frequency of "empty" nouns (e.g., 'it', 'man') and "empty" verbs (e.g., 'is', 'do') as an index of word-finding difficulty: In both groups, some subjects produced comparable numbers of empty nouns and verbs, while other subjects produced significantly more empty verbs. However, the Sentence Generation performance of one aphasic subject stood out overall by her tendency to avoid empty verbs and produce incomplete sentences. This pattern of performance was interpreted as a breakdown in an early stage of sentence planning that may be directly related to her diagnosis of transcortical motor aphasia.

Aphasia↗