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Biomedical subjects

P Day

Publications and source records attributed to P Day.

90 records · Page 5Linked to original sources

Modulation of the G0 to S phase transit time by insulin: potential involvement of protein phosphorylation.

BHK fibroblasts can be growth arrested by incubation in low serum (0.1%) medium. Growth is initiated by incubating cells in high serum (10%) medium. We have found that if the quiescent cells in low serum medium are incubated with insulin, the G0 to S transit time is decreased by two to six hours when serum (10%) is added back to the culture. The effect of insulin treatment of quiescent cells on the cellular phosphoprotein profile was examined. It was found that insulin stimulated the phosphorylation of a 96,000 dalton cytosol protein. This protein is also intensely phosphorylated in proliferating cells and may be one of the critical intracellular events to occur when a cell initiates growth.

Animals↗

Structural analysis of ricin and implications for inhibitor design.

Ricin is a potent cytotoxin with experimental and clinical uses; it has also been used as a poison. There is considerable interest in identifying or designing inhibitors of the toxin that could be administered as antidotes. The X-ray structure of ricin A-chain is known and a plausible mechanism of action has been proposed. This provides a structural and chemical framework around which inhibitors could be designed; such a structure-based project is underway. Computer programs such as DOCK, GRID, SYBYL, and CHEMX have been used to map the ricin A-chain binding site and to search for potential inhibitors. Inhibitor candidates can be assayed kinetically in a protein synthesis assay and binding can be observed crystallographically. Taken together, a workable search algorithm has been developed and initial tests indicate that at least one ricin A-chain inhibitor, pteroic acid, has been identified.

Animals↗

Coffin-Lowry syndrome and premature tooth loss: a case report.

Coffin-Lowry syndrome was first described by Coffin in 1966 and later by Lowry in 1971. Several oral manifestations have been described previously. We report a case with additional information on the histology of prematurely exfoliated teeth.

Child, Preschool↗

Outcomes for root-fractured permanent incisors: a retrospective study.

PURPOSE: The objective of this study was to assess the outcomes for treated root-fractured permanent incisors with respect to pulp vitality, root tissue union, and tooth survival and to examine the effects of clinical and radiographic parameters and rigid splinting on the outcome. METHODS: Eighty-four teeth were identified and data extracted from case notes prior to transfer to an SPSS data base for analysis. The odds ratios for each factor were calculated and the significance of differences was determined. Tooth loss and relevant risk variables were examined using Cox's regression model and Kaplan-Meyer survival curves. RESULTS: Fourteen (17%) had fractures in the apical third, 47 (56%) in the middle third, and 23 (27%) in the coronal (gingival) third. Twenty-four (29%) also had crown fractures involving enamel and dentine. Crown fractures were identified as significant risk factors for pulp vitality. Loss of pulp vitality, horizontal displacement, and extrusive displacement of the coronal fragment were significant risk factors for hard root tissue union. Survival was poorest with gingival third fractures with 14 (61%) of these teeth being lost. Splinting rigidly had no significant effect on pulp vitality and type of root tissue healing. CONCLUSIONS: Loss of pulp vitality was significantly associated with enamel-dentine crown fracture. Hard root tissue union was significantly affected by pulp necrosis and luxation of the coronal fragment. Survival was poorest for root fractures within the gingival third of the root. Splinting with rigid fixation had no significant effect on pulp vitality and type of root tissue union.

Adolescent↗