E2f3a and E2f3b make overlapping but different contributions to total E2f3 activity.

The E2f transcription factors are key downstream targets of the retinoblastoma protein tumor suppressor that control cell proliferation. E2F3 has garnered particular attention because it is amplified in various human tumors. E2f3 mutant mice typically die around birth and E2f3-deficient cells have a proliferation defect that correlates with impaired E2f target gene activation and also induction of p19(Arf) and p53. The E2f3 locus encodes two isoforms, E2f3a and E2f3b, which differ in their N-termini. However, it is unclear how E2f3a versus E2f3b contributes to E2f3's requirement in either proliferation or development. To address this, we use E2f3a- and E2f3b-specific knockouts. We show that inactivation of E2f3a results in a low penetrance proliferation defect in vitro whereas loss of E2f3b has no effect. This proliferation defect appears insufficient to disrupt normal development as E2f3a and E2f3b mutant mice are both fully viable and have no detectable defects. However, when combined with E2f1 mutation, inactivation of E2f3a, but not E2f3b, causes significant proliferation defects in vitro, neonatal lethality and also a striking cartilage defect. Thus, we conclude that E2f3a and E2f3b have largely overlapping functions in vivo and that E2f3a can fully substitute for E2f1 and E2f3 in most murine tissues.

Preoperative dobutamine stress echocardiography versus cardiac arteriography for risk assessment prior to renal transplantation.

Because coronary artery disease is the leading cause of death in patients with end-stage renal disease, we prospectively studied the prognostic value of dobutamine stress echocardiography (DSE) compared to coronary angiography (CA) as an evaluative tool. Thirty-three patients at high risk for coronary artery disease were selected from a cohort of 133 renal transplant candidates and underwent both DSE and CA. In this study, the value of DSE was found to exist in its strong negative predictive value (92%). A negative DSE coupled with a negative clinical cardiac evaluation was found to practicably exclude the necessity for CA. DSE can thus serve as a non-invasive, low cost screening test.

Recent patterns and predictors of antipsychotic medication regimens used to treat schizophrenia and other psychotic disorders.

Up-to-date data are needed on the types of treatments used by psychiatrists and the reasons for use of particular treatments. Using 1997 American Psychiatric Association (APA) Practice Research Network (PRN) Study data on patients with schizophrenia and other psychotic disorders, we identified the characteristics of antipsychotic medications (APMs) currently being prescribed and factors associated with the use of particular regimens. In this study population, use of the newer APMs, including risperidone, olanzapine, and clozapine, has increased rapidly and now accounts for over one-half of all APM use. Other intriguing findings include the fact that one-sixth of patients with schizophrenia and other psychotic disorders are concurrently treated with two or more APMs. Factors associated with being prescribed one of the newer APMs risperidone or olanzapine include being elderly, having more education, being white, having psychiatric comorbidity, and making fewer recent visits to a psychiatrist. The APA PRN Study data are an important new resource for mental health services researchers.

Eosinophilic gastroenteritis presenting as an obstructing cecal mass--a case report and review of the literature.

The causes of colonic obstruction are protean. Less common is the diagnosis of eosinophilic gastroenteritis (EGE). EGE is more common as a cause of more proximal bowel obstruction. To our knowledge, this case represents one of the only reported cases of such a lesion causing obstruction in the cecum.