ABSTRACT
Increasingly, physicians rely on computerized tomography (CT) to aid in the workup of acute appendicitis (AA) in children despite the potential negative effects of CT-associated radiation exposure. Few studies have investigated the context or location in which the decision to perform CT for AA is made. We sought to determine where the decision to use CT was made during the initial workup of pediatric patients who later underwent an appendectomy. We reviewed the medical record of all patients at a children's hospital (CH) receiving appendectomy over 10.5 years. We abstracted clinical variables using an established clinical AA scoring system, demographics and outcome variables. Patients who underwent CT were compared with those who did not. Additionally, we identified the location where the CT was performed. Our children's hospital was compared with referring hospitals (RHs) with regard to utilization of CT imaging. Five hundred and forty-six patients underwent appendectomy for AA at CH. Of these, 50 per cent underwent CT. Patients who initially presented at the RHs underwent CT at a significantly higher rate than those first presenting to CH (P < 0.0001). Moreover, we found that unlike at the RHs, patients with a higher AA score underwent CT at CH less often (P < 0.0002). RHs used CT more often than CH to diagnose AA in our cohort. CH avoided CT for patients with higher Alvarado scores. Further research is needed to elucidate factors that lead healthcare providers to use CT for children with suspected AA to eliminate unnecessary CT-associated radiation exposure.
Subject(s)
Appendectomy/methods , Appendicitis/diagnostic imaging , Tomography, X-Ray Computed/statistics & numerical data , Adolescent , Age Factors , Analysis of Variance , Appendectomy/statistics & numerical data , Appendicitis/diagnosis , Appendicitis/surgery , Chi-Square Distribution , Child , Child, Preschool , Cohort Studies , Female , Follow-Up Studies , Hospitals, Pediatric/statistics & numerical data , Humans , Logistic Models , Male , Preoperative Care/methods , Radiation Effects , Referral and Consultation/statistics & numerical data , Retrospective Studies , Risk Assessment , Treatment OutcomeABSTRACT
Ligation of the transmembrane protein T cell Ig and mucin domain (Tim)-1 can costimulate T cell activation. Agonistic Abs to Tim-1 are also capable of inducing T cell activation without additional stimuli. However, little is known about the biochemical mechanisms underlying T cell stimulation or costimulation through Tim-1. We show that a tyrosine in Tim-1 becomes phosphorylated in a lck-dependent manner, whereupon it can directly recruit p85 adaptor subunits of PI3K. This results in PI3K activation, which is required for Tim-1 function. We also provide genetic evidence that p85 expression is required for optimal Tim-1 function. Thus, we describe a pathway from Tim-1 tyrosine phosphorylation to the PI3K signaling pathway, which appears to be a major effector of Tim-1-mediated T cell activation.
