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Stephen Chapman

Publications and source records attributed to Stephen Chapman.

4 recordsLinked to original sources
PubMed2004

Skeletal injuries associated with sexual abuse.

BACKGROUND: Sexual abuse is often associated with physical abuse, the most common injuries being bruising and other soft-tissue injuries, but fractures occur in 5% of sexually abused children. The fractures described to date have formed part of the spectrum of injuries in these children and have not been specifically related to the abusive act. OBJECTIVE: To describe concurrent sexual abuse and fractures. MATERIALS AND METHODS: Three children with pelvic or femoral shaft injuries in association with sexual abuse. RESULTS: A 3-year-old girl with extensive soft-tissue injuries to the arms, legs and perineum also sustained fractures of both pubic rami and the sacral side of the right sacro-iliac joint. A 5-month-old girl with an introital tear was shown to have an undisplaced left femoral shaft fracture. A 5-year-old girl presented with an acute abdomen and pneumoperitoneum due to a ruptured rectum following sexual abuse. She had old healed fractures of both pubic rami with disruption of the symphysis pubis. CONCLUSIONS: Although the finding of a perineal injury in a young child may be significant enough for the diagnosis of abuse, additional skeletal injuries revealed by radiography will assist in confirmation of that diagnosis and may be more common than hitherto suspected.

Child Abuse, Sexual↗
PubMed2004

Resistance to signal activation governs design features of the MAP kinase signaling module.

Given its broad influence over numerous cell functions, redesigning the mitogen-activated protein (MAP) kinase signaling module would offer a powerful means to engineer cell behavior. Early challenges include identifying quantitative module features most relevant to biological function and developing simple design rules to predictably modify these features. This computational study delineates how features such as signal amplification, input potency, and dynamic range of output may be tuned by manipulating chief module components. Importantly, the model construction identifies a metric of resistance to signal activation that quantitatively predicts module features and design trade-offs for broad perturbations in kinase and phosphatase expression. Its predictive utility extends to dynamic properties such as signal lifetime, which often dictates MAP kinase effect on cell function. Taken together, we propose that predictably altering MAP kinase signaling by tuning resistance is not only a feasible engineering strategy, but also one exploited by natural systems to allow each MAP kinase to exert pleiotropic effects in a context-dependent manner. External stimuli not only activate kinases, but also alter phosphatase expression and activity, thereby reconfiguring a single module for quantitatively distinct modes of signaling such as transient vs. sustained dynamics, each with unique effects on cell function.

Computer Simulation↗