Biomedical subjects

K Neilson

Publications and source records attributed to K Neilson.

11 recordsLinked to original sources

PubMed2000

The contribution of visual search strategies to the development of pedestrian skills by 4-11 year-old children.

BACKGROUND: Young children in the 5-9 age range are particularly vulnerable to road accidents as pedestrians and previous research has identified a range of motivational and cognitive skill factors which may play a part in this. AIMS: The present study aimed to examine the extent to which the development of pedestrian skills in young children was related to individual differences in visual search strategies. SAMPLE: A sample of 180 children aged 4/5, 7/8 and 10/11 years was presented with tasks intended to assess their pedestrian skills. From this analysis a subset of 60 children was selected who had particularly high or low levels of pedestrian skills, together with a random sample of 10 adults, for more detailed analysis of their visual search strategies when confronted with the problem of crossing a road safely. METHOD: The children's pedestrian skills were assessed using three tasks based on slide and video presentations of real roadside situations; these tasks assessed the ability to identify safe places to cross the road, and to decide when it was safe to cross based on the ability to detect dangerous traffic and to co-ordinate information from different directions. Visual search strategies were assessed using a 'spot the difference' test and by analysing the head and eye movements of children and adults while they were carrying out the video task requiring them to co-ordinate information from different directions. This task was also used to make an assessment of individuals' processing speeds by measuring the time it took to make decisions that it was safe to cross the road. RESULTS: Significant differences emerged in strategic approaches between children in different age groups, and those who had high and low levels of pedestrians skills. A significant strategic shift appeared to be occurring around the age of 7/8 years. CONCLUSIONS: The results indicate that the explicit training of visual search strategies might well be beneficial, but that these cannot simply be the strategies of the adult pedestrian. Children may need to master simpler strategies which their slower processing speeds allow them to manage before they proceed on to the more sophisticated strategic approaches, typically involving predictions, used by older children and adults.

Accidents, Traffic↗

PubMed1994

Structure of the human cyclo-oxygenase-2 gene.

Cyclo-oxygenase (Cox), a rate-limiting enzyme in the synthesis of prostanoids, is encoded by two genes, Cox-1 and Cox-2, which are differentially expressed and regulated. Human Cox-1 and -2 polypeptides share 61% primary sequence identity. While the expression of Cox-1 is maximal in quiescent cells. Cox-2 expression is induced by growth factors and cytokines. We have screened a human genomic library with a probe from the 5'-untranslated region (UTR) of the human Cox-2 (hCox-2) cDNA and isolated two overlapping genomic clones. We have determined the DNA sequence of 0.8 kb upstream of the transcription start site, 6 kb of protein coding region, which includes 10 exons and 9 introns, as well as 2.5 kb of the 3'-UTR. The structures of the hCox-1 and hCox-2 and the murine TIS10 (Cox-2) genes are highly conserved, with a few exceptions. The 3'-UTRs of the Cox-1 and -2 genes are distinct; for example, the largest exon in the Cox-2 gene encodes the entire 3'-UTR, containing 22 copies of the 'AUUUA' RNA instability element. Sequence analysis of the 5'-flanking region has shown several potential transcription regulatory sequences, including a TATA box, a C/EBP motif, two AP-2 sites, three SP1 sites, two NF-kappa B sites, a CRE motif and an Ets-1 site. These efforts serve as a basis for future studies on transcriptional and post-transcriptional mechanisms of Cox-2 gene regulation.

Amino Acid Sequence↗

PubMed1994

Trigeminal neuralgia: a cautionary tale.

Trigeminal neuralgia is one of the paroxysmal symptoms of multiple sclerosis and may appear in the prodromal stage of this degenerative disease. A patient is described who was diagnosed as suffering from idiopathic trigeminal neuralgia and subsequently developed symptoms of generalised neurological disease, diagnosed as multiple sclerosis. Clinicians should be cautious when diagnosing younger patients as suffering from idiopathic trigeminal neuralgia and all suspicious cases should be referred to a neurologist for full assessment.

Adult↗

PubMed1993

Primary malignant rhabdoid tumour of the liver.

The authors describe the imaging features (from radiography, ultrasonography, computed tomography and angiography) of primary malignant rhabdoid tumour of the liver in an infant. The findings were not specific, and the diagnosis of this aggressive neoplasm was based on observations obtained with electron microscopy and immunohistochemical stains.

Humans↗

PubMed1992

Human cyclooxygenase-2 cDNA.

Cyclooxygenase (Cox), also known as prostaglandin (PG) H synthase (EC 1.14.99.1), catalyzes the rate-limiting step in the formation of inflammatory PGs. A major regulatory step in PG biosynthesis is at the level of Cox: growth factors, cytokines, and tumor promoters induce Cox activity. We have cloned the second form of the Cox gene (Cox-2) from human umbilical vein endothelial cells (HUVEC). The cDNA encodes a polypeptide of 604 amino acids that is 61% identical to the previously isolated human Cox-1 polypeptide. In vitro translation of the human (h)Cox-2 transcript in rabbit reticulocyte lysates resulted in the synthesis of a 70-kDa protein that is immunoprecipitated by antiserum to ovine Cox. Expression of the hCox-2 open reading frame in Cos-7 monkey kidney cells results in the elaboration of cyclooxygenase activity. hCox-2 cDNA hybridizes to a 4.5-kilobase mRNA species in HUVEC, whereas the hCox-1 cDNA hybridizes to 3- and 5.3-kilobase species. Both Cox-1 and Cox-2 mRNAs are expressed in HUVEC, vascular smooth muscle cells, monocytes, and fibroblasts. Cox-2 mRNA was preferentially induced by phorbol 12-myristate 13-acetate and lipopolysaccharide in human endothelial cells and monocytes. Together, these data demonstrate that the Cox enzyme is encoded by at least two genes that are expressed and differentially regulated in a variety of cell types. High-level induction of the hCox-2 transcript in mesenchymal-derived inflammatory cells suggests a role in inflammatory conditions.

Amino Acid Sequence↗

PubMed1990

Augmentation cystoplasty in rats: development of an animal model.

An animal model of the Long-Evans species of rats was developed to study the short-term and long-term effects of enterocystoplasty. Various enterocystoplasties were performed in 39 rats, including ileal in 29, colonic in 5 and gastric in 5. The followup period was 3 months. Frequency and pattern of voiding, 24-hour urinary collection for mucus production, and blood and urinary electrolytes were analyzed. All voiding parameters, renal function and biochemical studies remained normal. Mucus production was higher in the gastrocystoplasty and colocystoplasty than in ileocystoplasty cases. Postmortem histopathological examination of the enteropatch was performed, which showed urothelialization of the graft with native transitional epithelium extending over the junctional margin of the graft and covering the enteropatch mucosa. The enteropatch muscle orientation was maintained in all 3 types of grafts. We believe that the Long-Evans species of rats is a good model for the study of enterocystoplasty.

Animals↗

PubMed1989

Lymphotropic papovavirus early region is specifically regulated transgenic mice and efficiently induces neoplasia.

Transgenic mice have been generated which carry the early region of lymphotropic papovavirus (LPV). Eight of eleven founder animals died before 3 months of age after developing one or both of two distinct proliferative disorders. Of the three surviving animals, two are known to have rearranged or partial copies of the LPV genes. The majority of the founder animals (six) developed debilitating choroid plexus tumors by 26 to 42 days. Although this is the same tumor type induced by the simian virus 40 T-antigen gene, those induced by LPV appeared at a much younger age. The LPV early region was expressed in the brain tumors of these mice, as well as in the thymus and spleen. Expression in the latter two tissues reflects the cell-type specificity of the LPV enhancer demonstrated in cultured cells (i.e., lymphoid cells). Two founder animals (LP41 and LP50) gave rise to lines of mice that routinely develop lymphoproliferative disorders. LP50 and its LPV-positive offspring developed aggressive lymphomas and choroid plexus tumors. The transgenic offspring of LP41 also developed lymphomas. High levels of LPV RNA were expressed in the lymphomas of these mice as well as in the spleens and thymuses. The origin of the lymphomas from B- and T-cell lineages suggests that the LPV early genes are expressed in and can transform both of these cell types in vivo.

Animals↗

PubMed1989

Psychometric prediction of driving performance among the disabled.

A battery of psychometric and performance tests was administered to 25 subjects who were classified into able-bodied (n = 8), brain-injured (n = 10), and spinal cord injured groups (n = 7). All disabled subjects were regarded by their referring rehabilitation therapists as potential candidates for driver assessment. Data were analyzed to identify which measures were useful in differentiating among the groups and predicting driving performance. Results indicated that psychometric measures can be useful in predicting driving performance among disabled drivers. Nearly all the measures in the battery were significant predictors of driving ability, and some were highly predictive. The best was the oral version of the Symbol Digit Modalities test, which by itself accounted for 70% of the variance of the full-sized-vehicle driving score. Adding a second variable into a two-step multiple regression further increased the correlation between predictors and driving, accounting for almost 80% of the variance in driving score. These findings support the feasibility of developing a simple test battery to determine which disabled candidates are ready for in-vehicle assessment, and which candidates are not ready without further evaluation of cognitive and performance skills.

Adolescent↗

PubMed1988

Gene encoding the beta subunit of S100 protein is on chromosome 21: implications for Down syndrome.

S100 protein is a calcium-binding protein found predominantly in the vertebrate nervous system. Genomic and complementary DNA probes were used in conjunction with a panel of rodent-human somatic cell hybrids to assign the gene for the beta subunit of S100 protein to the distal half of the long arm of human chromosome 21. This gene was identified as a candidate sequence which, when expressed in the trisomic state, may underlie the neurologic disturbances in Down syndrome.

Chromosome Mapping↗

PubMed1987

Ectopic anterior pituitary corticotropic tumour in a six-year-old boy. Histological, ultrastructural and immunocytochemical study.

The report documents a silent, oncocytic, ACTH-producing ectopic anterior pituitary tumour in a 6-year-old boy. The invasive intrahemispheric neoplasm had no connection with the pituitary gland, the sella turcica or the sphenoid sinuses. The apparent similarities existing between this tumour, some choroid plexus carcinomas and steroid-producing neoplasms are discussed.

Adenoma↗

PubMed1977

Electron-capture GLC determination of nanogram to picogram amounts of isosorbide dinitrate.

A GLC method for the determination of plasma isosorbide dinitrate using electron-capture detection is described. The organic nitrates are especially suited for electron-capture detection if the detector temperature is optimized for maximum sensitivity, e.g., 175 degrees. Proper maintenance of the detector and column assures reproducible data in the low nanogram range. The extraction procedure described is simple, efficient, and expedient for processing large numbers of samples. The method was used to study plasma levels in four human volunteers after a single dose of a 5-mg chewable isosorbide dinitrate tablet. Concentration levels of isosorbide dinitrate as low as 0.5 ng/ml of plasma can be measured by this procedure.

Adult↗