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Biomedical subjects

P W Robinson

Publications and source records attributed to P W Robinson.

9 recordsLinked to original sources
PubMed2001

Studies on transcriptional regulation of the mucosal T-cell integrin alphaEbeta7 (CD103).

Integrin alphaEbeta7 is expressed almost exclusively by mucosal T cells and mucosal dendritic antigen-presenting cells (APCs) and is thought to be induced locally by transforming growth factor-beta (TGF-beta). In mice, mRNA for the alphaE subunit was found to be abundant in mucosal T cells but absent from other tissues. Exposure of a T-cell line to TGF-beta strongly up-regulated alphaE mRNA levels within 30 min, and nuclear run-on experiments established that regulation occurred at the level of transcription. The organization of the human alphaE gene and a very closely linked novel gene, ELG, was determined. The alphaE promoter was tested in T cells and fibroblasts and functioned equally well in both cell types and did not confer TGF-beta responsiveness. Regions of the promoter providing enhancer activity and phorbol 12-myristate 13-acetate (PMA) responsiveness were identified by deletion studies. DNAse 1 hypersensitivity analysis of 36 kb of the alphaE gene revealed one hypersensitive site, found only in alphaE+ cells, located near the transcription start points. These results show that, unlike the situation with other integrins, lineage specificity and cytokine responsiveness of alphaE transcription are not conferred by the proximal promoter. Specificity may depend on distant control elements that have not yet been identified.

Animals↗
PubMed2001

Successful ex vivo renal artery reconstruction and renal autotransplantation.

BACKGROUND: The increasing experience with renal allotransplantation has led to continuing development in vascular surgical techniques. These improvements have enabled complex ex vivo renal artery surgery and renal autotransplantation to be performed. The aims of the present study were to describe the results achieved with renal autotransplantation and ex vivo renal artery reconstruction (RAR) at the Newcastle Transplant Unit, John Hunter Hospital, and to review the current indications for such surgery. METHODS: A retrospective review was performed of patients who required renal autotransplantation with or without RAR at John Hunter Hospital, between 1991 and 1999. Data were obtained from the Newcastle Transplant Unit and the Medical Record Department of John Hunter Hospital. RESULTS: Two patients required ex vivo RAR and renal autotransplantation for severe fibromuscular dysplasia (FMD) complicated by stenoses and renal artery branch aneurysms. The third patient required autotransplantation for bilateral retroperitoneal fibrosis. There was one postoperative complication of pelviureteric junction obstruction that was treated successfully with a temporary ureteric stent. All patients demonstrated normal graft function and were normotensive on follow up, which ranged from 2.5 to 5 years. CONCLUSION: The present review confirms the long-term benefits of ex vivo RAR and renal autotransplantation that have been demonstrated by previous studies. In transplant units experienced with this surgery it has been shown to be a successful and durable technique for the treatment of a variety of vascular, urologic and other diseases.

Female↗
PubMed1981

A token system for a class of underachieving hyperactive children.

Using a BAB design, a token system requiring cooperative interaction was used to change the reading and vocabulary performance of an 18-member class of third-grade hyperactive boys. Four different colored tokens, which could be exchanged for 15 minutes of play on electrovideo games, were earned by successful completion of two tasks that involved learning to read and to use new vocabulary words in sentences, and two tasks in which the student served as a proctor to a student who had not yet completed those tasks. The mean number of tasks completed during the intervention periods rose to over nine times the number completed during reversal. Additionally, the average completion rate for the school district's standardized weekly reading level examinations rose from four to eight fold during the token conditions. All 18 students responded to the token program by increasing their academic performance.

Antisocial Personality Disorder↗
PubMed1978

Effects of error and errorless discrimination acquisition on reversal learning.

The effectiveness of trial-and-error, graded-choice, and verbal-instruction procedures on the acquisition and maintenance of a two-choice simultaneous color discrimination in an intradimensional double-reversal learning situation was studied using 18 first-grade children. After acquiring a red-green discrimination during one 70-trial session, the discriminative roles of the stimuli were reversed for 30 trials, followed by a second reversal for 30 trials. Children in the graded-choice and verbal-instruction groups acquired and maintained the discriminations with fewer errors than children who learned by trial and error. The importance of the results in terms of two-stage discrimination learning theories is pointed out and similarities between errorless learning and overtraining are discussed.

Journal Article↗
PubMed1974

The effects of total darkness on schedule control.

The study investigated the effect of total darkness on the key pecking of pigeons under fixed-ratio, variable-ratio, fixed-interval, and variable-interval schedules of food reinforcement. Eight pigeons were divided into groups of two, with each group conditioned to peck under one of the four schedules of reinforcement. Under an ABAB procedure, all pigeons experienced alternating light and dark conditions. The house- and keylights were (a) maintained at full intensity for the first 30 one-hour sessions, (b) faded out and disconnected over Sessions 31 through 50, (c) totally illuminated for Sessions 51 to 60, and (d) disconnected again for the final 10 sessions. Responding under the ratio schedules increased from 20% to 108% in the dark and responding under the interval schedules in the dark decreased by 37% to 93%.

Journal Article↗
PubMed1973

Application of a graded choice procedure to obtain errorless learning in children.

A simultaneous, two-choice color discrimination was carried out with three groups of four- to seven-year-old children. For Groups I and II, the opportunity to respond to the incorrect stimulus was controlled (graded) over three different conditions. First, only a red light (S+) and its retractable bar were presented (16 trials for Group I and 316 trials for Group II). Second, a green light (S-) was added with its correlated bar retracted for 14 trials. Third, 40 trials were given with both stimuli on and their correlated retractable bars extended. The opportunity to respond to S- was not graded for Group III children. They experienced only the third condition applied to Groups I and II. Responses to S+ were reinforced for all three groups, while responses to S- were not. Children in the first two groups made from zero to three responses to S-, while the control children emitted 11 to 46 errors. The results demonstrate that fading in S- or presenting S- early in the training procedure are sufficient, but not necessary conditions for errorless learning.

Journal Article↗