A Theileria annulata DNA binding protein localized to the host cell nucleus alters the phenotype of a bovine macrophage cell line.

The apicomplexan parasite Theileria annulata is the only intracellular eukaryote that is known to induce the proliferation of mammalian cells. However, as the parasite undergoes stage differentiation, host cell proliferation is inhibited, and the leukocyte is eventually destroyed. We have isolated a parasite gene (SuAT1) encoding an AT hook DNA binding polypeptide that has a predicted signal peptide, PEST motifs, nuclear localization signals, and domains which indicate interaction with regulatory components of the higher eukaryotic cell cycle. The polypeptide is localized to the nuclei of macroschizont-infected cells and was detected at significant levels in cells that were undergoing parasite stage differentiation. Transfection of an uninfected transformed bovine macrophage cell line, BoMac, demonstrated that SuAT1 can modulate cellular morphology and alter the expression pattern of a cytoskeletal polypeptide in a manner similar to that found during the infection of leukocytes by the parasite. Our findings indicate that Theileria parasite molecules that are transported to the leukocyte nucleus have the potential to modulate the phenotype of infected cells.

Erythropoietin therapy in children with bronchiolitis and anemia.

OBJECTIVE: Critically ill children with bronchiolitis often require red blood cell transfusions. Anemia normally results in increased circulating erythropoietin concentrations; however, critical illness has been associated with a blunted erythropoietin response. Treatment with erythropoietin decreases the need for red blood cell transfusion in several disease states. We hypothesized that critically ill children with bronchiolitis and anemia would have a circulating erythropoietin deficiency and that treatment with exogenous erythropoietin would increase reticulocyte count and hematocrit and reduce red blood cell transfusion requirements. DESIGN: Randomized, blinded, placebo-controlled trial. SETTING: Children's hospital. PATIENTS: Critically ill children with bronchiolitis, anemia, and respiratory failure. Anemia was defined as a hematocrit >2 SD below normal for age. INTERVENTION: Patients were randomized to one of two groups. In the erythropoietin group, patients received daily intravenous erythropoietin. In the control group, patients received daily intravenous placebo. Both groups were treated with elemental iron. MEASUREMENTS AND MAIN RESULTS: Blood for complete blood count, reticulocyte count, and ferritin and erythropoietin concentration was obtained at admission and discharge. Red blood cell transfusions were administered to patients with a persistent oxygen requirement and a hematocrit of <25%. Outcome variables included number of red blood cell transfusions, change in reticulocyte count, ferritin values, and circulating erythropoietin values between groups. Forty-four patients completed the study (mean 3.1 +/- 0.6 months), with a baseline hematocrit of 27.6 +/- 0.5%, ventilator days of 8.2 +/- 0.6, and pediatric intensive care unit length of stay of 9.8 +/- 0.6 days. There were no significant baseline demographic differences between the control and erythropoietin groups. Ten of 22 (45%) children in the erythropoietin group required red blood cell transfusion compared with 11 of 22 (50%) in the control group (p = nonsignificant). The increase in reticulocyte count was greater in the erythropoietin group compared with the control group (2.1 +/- 0.3% to 4.7 +/- 0.7%, p = .003 vs. 2.1 +/- 0.3% to 2.7 +/- 0.5%, p = nonsignificant). CONCLUSIONS: Despite a favorable reticulocyte and circulating erythropoietin response, red blood cell transfusion requirements were not significantly diminished by erythropoietin treatment in children with bronchiolitis and respiratory failure. Erythropoietin cannot be routinely recommended for this patient population.

Continuation of transpyloric feeding during weaning of mechanical ventilation and tracheal extubation in children: a randomized controlled trial.

BACKGROUND: Nutrition support is essential in the management of critically ill children. There is no current literature to support the common practice of discontinuing enteral nutrition delivered through a transpyloric feeding tube during the tracheal extubation process. We conducted a prospective, randomized controlled trial in mechanically ventilated children to examine the safety and efficacy of continuous transpyloric feeding compared with interrupted transpyloric feeding at the time of tracheal extubation. METHODS: Subjects were randomly assigned to receive transpyloric feeding throughout the tracheal extubation process (Continuous Group) or to have transpyloric feeding discontinued 4 hours before tracheal extubation and restarted 4 hours after tracheal extubation (Interrupted Group). Data consisting of patient demographics, admission pediatric risk of mortality (PRISM) score, diagnoses, adverse events (feeding intolerance, gastroesophageal reflux, and pulmonary aspiration), daily feeding volume, and caloric intake were recorded for the 3 days surrounding tracheal extubation. RESULTS: Fifty-nine patients completed the study (29 in Continuous Group, 30 in Interrupted Group). There was no episode of pulmonary aspiration in either group. The Continuous Group experienced 4 adverse events, whereas the Interrupted Group experienced 3 adverse events (p = not significant). The Continuous Group received 92 +/- 2.5% of their caloric goal on the day of weaning from the ventilator (day 1) and 93 +/- 3.2% on the day of tracheal extubation (day 2) compared with 76 +/- 4.2% and 43 +/- 4.3%, respectively, in the Interrupted Group (p < .004 and p < .0001, respectively). CONCLUSIONS: Continuous transpyloric feeding during weaning from the ventilator and tracheal extubation is safe and results in the delivery of more optimal nutrition.