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Biomedical subjects

S Tyler

Publications and source records attributed to S Tyler.

29 records · Page 2Linked to original sources
PubMed1988

In vivo treatment with IL-1 reduces the severity and duration of antigen-induced arthritis in rats.

IL-1 has been implicated in the pathogenesis of arthritis. Although IL-1 injected in vivo into normal joints results in a transient inflammatory reaction, we have shown that three weekly repetitive injections of IL-1 do not produce a progressive inflammatory condition suggestive of chronic arthritis. In fact, priming normal joints with three weekly IL-1 intraarticular injections results in a significant reduction in joint swelling and diminished histopathologic alterations/lesions caused by subsequent methylated BSA-induced arthritis. Similarly, post treatment with IL-1 intraarticular injection after arthritis induction reduced arthritic swelling and joint injury if IL-1 was given during the developing stage of arthritis. Our results suggest that IL-1 might limit arthritic inflammation and progressive cartilage destruction through an, as yet, undetermined mechanism(s). Further in vivo investigations are required to determine the therapeutic utility of IL-1 in reducing early arthritic inflammation.

Animals↗
PubMed1988

Cognitive profiles of groups of poor readers and dyslexic children on the British Ability Scales.

Two samples of children with reading difficulties--145 poor readers and 121 dyslexic children--were tested on the British Ability Scales (BAS). The poor readers were classified, using Rutter & Yule's (1975) criteria, into children with specific reading retardation and general reading backwardness. These children's profiles of scores on the BAS were also entered into a cluster analysis which provided some confirmation of the validity of the Rutter & Yule classification. The BAS scores of the dyslexic children were also entered into a cluster analysis. Three groups were identified: 30 with mixed visuo-spatial and linguistic processing problems, 52 with sequential processing problems, and 39 with problems in the holistic retrieval of information. It was concluded that the data lend support to the view that children with specific reading retardation, and dyslexic children in particular, are not homogeneous in their cognitive profiles. Finally, each group identified above was analysed for fit to the Lawson & Inglis (1985) principal components model of learning disability. The fit to the model for most groups was poor. It was concluded that a model which implicates left hemisphere aetiology for all LD children is inadequate. Some benefit, however, is likely to accrue from the more rigorous definition of specific subtypes, and in this endeavour the BAS appear to offer a useful advance in such assessment and identification.

Aptitude Tests↗
PubMed1988

Expression of the N-myc oncogene in Wilms' tumour and related tissues.

Tissue samples and cell cultures from Wilms' tumour matched histologically normal kidney samples and EBV transformed B cells from the same patients, were analysed to detect changes in the structure and expression of the N-myc oncogene. The levels of expression of HLA class I and hypoxanthine guanine phosphoribosyl transferase were also measured in the various RNA preparations. Related tissue samples, from sources including congenital mesoblastic nephroma, paediatric neuroblastoma and a number of foetal tissues were also tested. Northern blot analysis indicated that the levels of N-myc were higher in Wilms' tumour tissues (with no parallel increase in gene copy number) compared to all other sources of material including foetal kidney. Particularly high levels of expression were observed in a number of the Wilms' tumours, several of which produced metastases. In situ hybridization, using [35S]-labelled RNA probes, confirmed that the high levels of N-myc RNA were present in the blastemal elements in the Wilms' tumour. All the tissue cultures, and tissue samples from other sources, except foetal brain and neuroblastoma, contained uniformly low levels of N-myc RNA.

Child↗
PubMed1987

Learning disabilities and intelligence test results: a principal components analysis of the British Ability Scales.

Two samples of children with reading difficulties--145 poor readers whose word reading was one standard deviation or more below the mean and 121 dyslexic children-were tested on the British Ability Scales. The purpose of the investigation was to examine whether they would score relatively poorly on verbal tests and relatively well on non-verbal tests along the lines suggested by Lawson & Inglis (1985). Also the question of sex differences was investigated. The BAS results tended to confirm the Lawson & Inglis finding that (1) children with learning disabilities in general have verbal deficits and show significantly higher performance on non-verbal tasks, and that (2) this tendency is more pronounced in males than in females. The results, although statistically significant, are not totally consistent either within or between samples. The discussion considers possible explanations for the findings and the possibility that different subgroups of these samples might show differential effects.

Adolescent↗
PubMed1979

Distinctive features of cilia in metazoans and their significance for systematics.

A comparative study of epidermal cilia in the Turbellaria and Nemertea has revealed features in these organelles that are specific to certain taxonomic groups. Turbellarians of the order Acoela, in particular, have a characteristic pattern of axonemal filament termination in the distal tips of their cilia and a characteristic ciliary rootlet system that is not seen in other turbellarian orders nor in other metazoans. Each epidermal cilium in acoels has a typical 9 + 2 axonemal pattern through the main part of its length, but near its distal tip there is an abrupt shelf-life narrowing at which filaments 4-7 terminate; filaments 1, 2, 8 and 9 continue into the thinner distal-most part of the shaft along with singlet microtubules from the axonemal center. The rootlet system in acoel cilia involves an interconnecting pattern with lateral connectives. The unique structure of these cilia has systematic and phylogenetic significance for the Acoela, and it is argued that ultrastructural characters in general, including characters of organelles, can be validly applied to the phylogeny and systematics of the Metazoa.

Animals↗
PubMed1975

Uniflagellate spermatozoa in Nemertoderma (Turbellaria) and their phylogenetic significance.

An ultrastructural study of Nemertoderma (Turbellaria, Nemertodermatida) has revealed that its spermatozoa have only a single falgellum. This is the first uniflagellate spermatozoon known in the Turbellaria; it is indicative of the primitiveness of Nemertoderma and is evidence in support of the view that the Turbellaria as a whole are among the most primitive living Bilateria.

Acrosome↗
PubMedDate not supplied

Interleukin-4 (B-cell stimulatory factor-1) augments the in vivo generation of cytotoxic cells in immunosuppressed animals.

Thymus-derived lymphocytes (T cells) are thought to play an important role in the recognition and destruction of neoplastic cells in the host. This principle has provided a foundation for the establishment of therapy with T-cell-stimulating lymphokines, notably interleukin-2, as an approach to the eradication of certain malignancies. Another lymphokine, B-cell-stimulatory factor-1 (BSF-1), also known as IL-4, has also been shown to be capable of inducing T-cell proliferation and cytolytic activity in vitro. We demonstrate herein that in immunosuppressed mice, in vivo IL-4 administration enhances the ability of treated animals to generate cytotoxic T lymphocytes directed against an allogeneic tumor challenge. Moreover, IL-4 is approximately 25 times more effective, on a weight basis, than is IL-2 in augmenting cytotoxic T-lymphocyte activity. This difference in efficiency between the two lymphokines may be partly due to the in vivo half-life. We have found that IL-4 has a serum half-life of 19 +/- 2 min following intravenous administration, in contrast to the half-life of IL-2, which has been reported to be 3.7 min +/- 0.8. These results are not only of interest for our basic understanding of the physiological role of IL-4 but may have immediate importance in clinical settings where lymphokine therapy is contemplated.

Animals↗