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Colin Smith

Publications and source records attributed to Colin Smith.

17 recordsLinked to original sources
PubMed2026

Distinct cellular phenotypes of language and executive decline in amyotrophic lateral sclerosis.

Cognitive manifestations, including impairments in language and executive functions, are seen in amyotrophic lateral sclerosis (ALS), but the underlying mechanisms remain unclear. We mapped prefrontal cortex regions from ALS patients by integrating spatial and single-nucleus transcriptomics in a cognitively stratified patient cohort. We uncover that cognitive impairment in ALS is associated with distinct patterns of neuronal dysfunction and glial-vascular dysregulation that vary by region and cognitive subtype. Executive dysfunction is linked to reduced mitochondrial and synaptic activity in deep-layer dorsolateral prefrontal cortex neurons, whereas language-related deficits track with a diffuse pan-regional response involving glial and vascular abnormalities. Our analyses, validated by multiplexed imaging, further identify signatures in the prefrontal cortex that span both motor and cognitive phenotypes, including a multicellular gliosis response. The findings reveal that clinical heterogeneity in ALS is driven by phenotype-specific cellular interactions in motor and non-motor regions of the brain.

Amyotrophic Lateral Sclerosis↗
PubMed2006

Typing single polymorphic nucleotides in mitochondrial DNA as a way to access Middle Pleistocene DNA.

In this study, we have used a technique designed to target short fragments containing informative mitochondrial substitutions to extend the temporal limits of DNA recovery and study the molecular phylogeny of Ursus deningeri. We present a cladistic analysis using DNA recovered from 400 kyr old U. deningeri remains, which demonstrates U. deningeri's relation to Ursus spelaeus. This study extends the limits of recovery from skeletal remains by almost 300 kyr. Plant material from permafrost environments has yielded DNA of this age in earlier studies, and our data suggest that DNA in teeth from cave environments may be equally well preserved.

Animals↗
PubMed2006

Neurobehavioral functional deficits following closed head injury in the neonatal pig.

Neurobehavioral deficits in higher cortical systems have not been described previously in a large animal model of diffuse brain injury. Anesthetized 3-5 day old piglets were subjected to either mild (142 rad/s) or moderate (188 rad/s) rapid non-impact axial rotations of the head. Multiple domains of cortical function were evaluated 5 times during the 12 day post-injury period using tests of neurobehavioral function devised for piglets. There were no observed differences in neurobehavioral outcomes between mild injury pigs (N=8) and instrumented shams (N=4). Moderately injured piglets (N=7) had significantly lower interest in exploring their environment and had higher failure rates in visual-based problem solving compared to instrumented shams (N=5) on days 1 and 4 after injury. Neurobehavioral functional deficits correlated with neuropathologic damage in the neonatal pigs after inertial head injury. Injured axons detected by immunohistochemistry (beta-APP) were absent in mild injury and sham piglets, but were observed in moderately injured piglet brains. In summary, we have developed a quantitative battery of neurobehavioral functional assessments for large animals that correlate with neuropathologic axonal damage and may have wide applications in the fields of cardiac resuscitation, stroke, and hypoxic-ischemic brain injury.

Amyloid beta-Protein Precursor↗
PubMed2005

Cattle domestication in the Near East was followed by hybridization with aurochs bulls in Europe.

Domesticated cattle were one of the cornerstones of European Neolithisation and are thought to have been introduced to Europe from areas of aurochs domestication in the Near East. This is consistent with mitochondrial DNA (mtDNA) data, where a clear separation exists between modern European cattle and ancient specimens of British aurochsen. However, we show that Y chromosome haplotypes of north European cattle breeds are more similar to haplotypes from ancient specimens of European aurochsen, than to contemporary cattle breeds from southern Europe and the Near East. There is a sharp north-south gradient across Europe among modern cattle breeds in the frequencies of two distinct Y chromosome haplotypes; the northern haplotype is found in 20 out of 21 European aurochsen or early domestic cattle dated 9500-1000 BC. This indicates that local hybridization with male aurochsen has left a paternal imprint on the genetic composition of modern central and north European breeds. Surreptitious mating between aurochs bulls and domestic cows may have been hard to avoid, or may have occurred intentionally to improve the breeding stock. Rather than originating from a few geographical areas only, as indicated by mtDNA, our data suggest that the origin of domestic cattle may be far more complex than previously thought.

Animals↗
PubMed2005

Prehistoric contacts over the Straits of Gibraltar indicated by genetic analysis of Iberian Bronze Age cattle.

The geographic situation of the Iberian Peninsula makes it a natural link between Europe and North Africa. However, it is a matter of debate to what extent African influences via the Straits Gibraltar have affected Iberia's prehistoric development. Because early African pastoralist communities were dedicated to cattle breeding, a possible means to detect prehistoric African-Iberian contacts might be to analyze the origin of cattle breeds on the Iberian Peninsula. Some contemporary Iberian cattle breeds show a mtDNA haplotype, T1, that is characteristic to African breeds, generally explained as being the result of the Muslim expansion of the 8th century A.D., and of modern imports. To test a possible earlier African influence, we analyzed mtDNA of Bronze Age cattle from the Portalón cave at the Atapuerca site in northern Spain. Although the majority of samples showed the haplotype T3 that dominates among European breeds of today, the T1 haplotype was found in one specimen radiocarbon dated 1800 calibrated years B.C. Accepting T1 as being of African origin, this result indicates prehistoric African-Iberian contacts and lends support to archaeological finds linking early African and Iberian cultures. We also found a wild ox haplotype in the Iberian Bronze Age sample, reflecting local hybridization or backcrossing or that aurochs were hunted by these farming cultures.

Africa, Northern↗
PubMed2005

The gonadotrophins response to GnRH test is not a predictor of neurological lesion in girls with central precocious puberty.

OBJECTIVES: To assess the value of gonadotrophin releasing hormone (GnRH) stimulation test in identifying intracranial abnormality in girls with central precocious puberty (CPP). PATIENTS AND METHODS: A study of 67 girls diagnosed with CPP who underwent cranial MRI scans. Patients were not receiving any therapy and there were no neurological signs or symptoms at presentation. Patients underwent evaluation of GnRH stimulation test and plasma oestradiol levels at presentation. RESULTS: Mean age at onset of puberty was 6.2 years (range 2.0 to 8.0 years). Intracranial abnormalities were present in 10 (15%) patients, while 57 girls (85%) had no abnormalities. No significant difference was shown between girls with intracranial abnormality and girls without intracranial abnormality in basal LH or FSH values, peak LH or FSH values, LH/FSH peak ratios, peak LH/basal LH ratios, peak FSH/ basal FSH ratios at presentation. CONCLUSION: GnRH stimulation test does not identify those with underlying intracranial abnormality at presentation. MRI imaging remains necessary in all cases of central precocious puberty in girls.

Brain Neoplasms↗
PubMed2004

Bioconductor: open software development for computational biology and bioinformatics.

The Bioconductor project is an initiative for the collaborative creation of extensible software for computational biology and bioinformatics. The goals of the project include: fostering collaborative development and widespread use of innovative software, reducing barriers to entry into interdisciplinary scientific research, and promoting the achievement of remote reproducibility of research results. We describe details of our aims and methods, identify current challenges, compare Bioconductor to other open bioinformatics projects, and provide working examples.

Computational Biology↗
PubMed2004

Meningiomas.

Meningiomas are by far the most common tumours arising from the meninges. Progressive enlargement of the tumour leads to focal or generalised seizure disorders or neurological deficits caused by compression of adjacent neural tissue. Surgery remains the primary treatment of choice, although the use of fractionated radiotherapy or stereotactic single-dose radiosurgery is increasing for meningiomas that are incompletely excised, surgically inaccessible, or recurrent and either atypical or anaplastic. Although most meningiomas have good long-term prognosis after treatment, there are still controversies over management in a proportion of cases. We review various features of meningioma biology, diagnosis, and treatment and provide an overview of the current rationale and evidence base for the various therapeutic approaches.

Humans↗
PubMed2004

Correlation of growth factor receptor expression with clinical growth in vestibular schwannomas.

OBJECTIVE: To examine the relationship between growth rate of vestibular schwannomas and the expression of various growth factor receptors. STUDY DESIGN: Retrospective case review of clinical growth rate in conjunction with a histopathologic and immunohistochemical reexamination of archival specimens. SETTING: A tertiary referral neurotologic center. PATIENTS: Three groups: a historical group to act as controls, consisting of 30 patients with sporadic vestibular schwannomas removed before the unit adopted an initial interval scan policy; a group of 14 patients with sporadic vestibular schwannomas who had undergone an initial interval scan policy, showed radiologic evidence of growth, and therefore had their schwannoma removed; and a group of 16 schwannomas removed from 11 neurofibromatosis Type 2 patients. MAIN OUTCOME MEASURES: A comparison between the three clinical groups using immunohistochemical studies to determine the level of expression of the proliferation factor Ki-67, c-erbB-2, and c-erbB-3 receptors and fibroblastic growth factor receptors 1 and 4. RESULTS: The level of expression of the proliferation factor Ki-67 was very low and similar in all three groups. C-erbB-2 and c-erbB-3 receptors were not expressed in any of the groups. fibroblastic growth factor receptor 4 expression was not significantly different, but there was a variation in the expression of fibroblastic growth factor receptor 1 between the three groups that correlated well with the differing incidence of growth in the groups. The increase in expression of fibroblastic growth factor receptor 1 in the neurofibromatosis Type 2 group was not statistically significant, but the increase in expression of fibroblastic growth factor receptor 1 in the growing sporadic group was statistically significant when compared with the historical controls. The level of fibroblastic growth factor receptor 1 expression correlates significantly with the rate of growth as measured on interval magnetic resonance imaging. CONCLUSIONS: Overexpression of fibroblastic growth factor receptor 1 has a positive correlation with the incidence and the rate of growth of sporadic vestibular schwannomas.

Gene Expression Regulation, Neoplastic↗
PubMed2004

Intercellular communication and human hepatocellular carcinoma.

We have previously reported that gap junction-mediated intercellular communication (GJIC) can be restored in junctionally deficient human prostate epithelial cells, also suggesting that GJIC activity is regulated by estrogen. In the present work, we report studies on sex steroid regulation of GJIC and proliferative activity in both nontumoral (Chang liver, CL) and malignant (HepG2, Huh7) human liver cells. Junctional activity and liver cell growth were measured using the scrape-loading/dye-transfer (SL/DT) and the MTS assay, respectively. Using the SL/DT, only Huh7 cells exhibited a moderate degree of junctional activity in basic conditions, while neither CL nor HepG2 cells showed functional GJIC. Under exactly the same experimental approach used for prostate studies, we observed that, once again, both estrogen (either estradiol or estrone) and FK induce a significant increase of GJIC in Huh7 cells, while exposure of HepG2 cells to FK produces only a limited rise of junctional activity in this cell line. However, estrogen induced a significant increase and reduction of the proliferative activity of CL and Huh7 cells, respectively, while growth of HepG2 cells was not affected. While the above evidence suggests that estrogens are primarily implicated in growth regulation and communication of both prostate and liver epithelial cells, it also implies that compounds able to restore GJIC in junctionally deficient cells or prevent its disruption in junctionally proficient cells may be used for development of new strategies in the prevention and/or treatment of several human malignancies, including hepatocellular carcinoma (HCC).

Carcinoma, Hepatocellular↗
PubMed2003

Necrotizing scleritis after intraocular surgery associated with the use of polyester nonabsorbable sutures.

We present 2 elderly patients who developed necrotizing scleritis after cataract extraction in which the wound was sutured with polyester. In the first case, a 73-year-old woman who had right phacoemulsification via a limbal incision developed necrotizing scleritis 8 months after surgery. The eye became progressively painful and phthisical, necessitating enucleation. Microscopic examination of the enucleated globe showed a predominantly lymphocytic infiltration of the ocular tissues with no evidence of an infectious agent. In the second case, a 78-year-old woman had bilateral extracapsular cataract extraction through a limbal incision closed with a polyester suture. The patient presented 3 years later with bilateral necrotizing sclerokeratitis. No underlying systemic vasculitis or autoimmune condition was identified in either patient. To our knowledge, the association of necrotizing scleritis after intraocular surgery and polyester fiber suture material (Mersilene) has not been described.

Aged↗
PubMed2003

The differing outcomes of hyperthyrotropinaemia.

Hyperthyrotropinaemia, in which normal levels of T4 occur in association with raised TSH, is picked up on neonatal screening. The outcome of children with persistent hyperthyrotropinaemia is uncertain. The study objective was to evaluate the outcome of children with the persistent form of hyperthyrotropinaemia. We carried out a retrospective analysis on children who attended one institution over the last 20 years with this diagnosis. Eight children were diagnosed with hyperthyrotropinaemia lasting more than 3 months in total. Four had a transient form lasting between 3 and 18 months in total. Three continue to have persistently raised TSH at 5, 9 and 17 years, respectively. One patient became biochemically hypothyroid at 1 year of age requiring treatment with replacement thyroxine. All of our group had normal growth and development. We recommend that thyroid function monitoring should continue in all children with hyperthyrotropinaemia until the thyroid function tests have normalised.

Congenital Hypothyroidism↗
PubMed2002

Comparative subcellular immunolocation of polypeptides associated with xylan and callose synthases in French bean (Phaseolus vulgaris) during secondary wall formation.

The Golgi apparatus of plant cells is thought to be the main site of synthesis of cell wall matrix polysaccharides and the terminal glycosylation of glycoproteins. Much of this evidence still depends on earlier biochemical studies employing subcellular fractionation. However acquiring pure Golgi membranes is still difficult and the question of spatial organisation of glycosyl transferases can be addressed by immunolocation of the enzymes. An antibody to a xylan synthase-associated polypeptide from French bean, the enzyme which synthesises the core polysaccharide for secondary wall xylan, has been raised and shown to inhibit its activity. Xylan is deposited in secondary thickenings and the xylan synthase was only detected in appreciable amounts in developing xylem cells. The location within the Golgi stack was observed throughout the dictyosomes. Some enzyme subunits were also detected in post-Golgi vesicles. A second antibody to a non-catalytic M(r) 65000 subunit of beta 1,3- glucan (callose) synthase was used for a comparative study. Although the bulk of this enzyme has been detected in previous studies at plasmamembrane-wall interfaces in sieve plates and stressed tissue, a Golgi-location can be observed in root tip meristematic cells during cell plate formation. The enzyme was present throughout the stacks. Callose was also immunolocated in a similar manner to xylan in secondary walls and thickenings and in pits in developing xylem. In these cells, the callose synthase was detected at the surface of the growing thickenings and the plasmamembrane within the pits.

Blotting, Western↗
PubMed2002

Nerve sheath tumors of the sellar region.

Nerve sheath tumors, including schwannomas and neurofibromas, rarely affect the sellar region. The authors report two such cases that were mistaken for pituitary adenomas on the basis of clinical and imaging features.

Adenoma↗
PubMed2002

Personal understanding and target understanding: mapping influences on the outcomes of learning.

BACKGROUND: Among the many theories of learning, few have been developed specifically for education. Most have explained learning in terms of either the individual activities of the learner or the design of the learning context; yet both are important in education. Each theory applies strictly only to the context for which it was developed, and yet quite general implications for education are often suggested. AIMS: 1. To review qualitative research on learning carried out within the classroom and to identify some of the major influences on the quality of learning outcomes. 2. To develop a conceptual framework based on this research which seeks to explain differences in levels and forms of understanding. METHOD: Model building based on reviews of research on learning in schools and universities. ANALYSIS: A conceptual framework was developed from the review of the literature which emphasises the activities of both teachers and students and the influences on learning outcomes of both the individual and the social context. The framework introduces a distinction between 'target' and 'personal' understanding to draw attention to the differing ways in which curriculum designers, teachers and students define knowledge and conceptualise the teaching-learning process. It also suggests how these conceptualisations influence the level of understanding reached by students. The framework is intended to encourage teachers and curriculum designers to think about the likely effects of the tasks and conditions they are providing for students, and to consider ways of strengthening the emphasis on conceptual understanding. By drawing on research findings from both schools and universities, a way of thinking about teaching and learning is indicated which can, to some extent, be generalised across educational contexts.

Cognition↗