Appendectomy Versus Observation for Appendicitis in Neutropenic Children With Cancer.

BACKGROUND: Optimal management of neutropenic appendicitis (NA) in children undergoing cancer therapy remains undefined. Management strategies include upfront appendectomy or initial nonoperative management. We aimed to characterize the effect of management strategy on complications and length of stay (LOS) and describe implications for chemotherapy delay or alteration. METHODS: Sites from the Pediatric Surgery Oncology Research Collaborative performed a retrospective review of children with NA over a 6-year period. RESULTS: Sixty-six children, with a median age of 11 years (range 1-17), were identified with NA while undergoing cancer treatment. The most common cancer diagnoses were leukemia (62%) and brain tumor (12%). Upfront appendectomy was performed in 41% of patients; the remainder had initial nonoperative management. Rates of abscess or perforation at diagnosis were equivalent in the groups (30% vs 24%; P = .23). Of patients who had initial nonoperative management, 46% (17 of 37) underwent delayed appendectomy during the same hospitalization. Delayed appendectomy was due to failure of initial nonoperative management in 65% (n = 11) and count recovery in 35% (n = 6). Cancer therapy was delayed in 35% (n = 23). Initial nonoperative management was associated with a delay in cancer treatment (46% vs. 22%, P = .05) and longer LOS (29 vs 12 days; P = .01). Patients who had initial nonoperative management and delayed appendectomy had a higher rate of postoperative complications (P < .01). CONCLUSIONS: In pediatric patients with NA from oncologic treatment, upfront appendectomy resulted in lower complication rates, reduced LOS, and fewer alterations in chemotherapy regimens compared to initial nonoperative management.

Unraveling the Mechanism of Catalytic Water Oxidation via de Novo Synthesis of Reactive Intermediate.

Artificial photosynthesis could promise abundant, carbon-neutral energy, but implementation is currently limited by a lack of control over the multi-electron catalysis of water oxidation. Discoveries of the most active catalysts still rely heavily on serendipity. [Ru(tpy)(bpy)(H2O)]2+ (1; bpy = 2,2'-bipyridine, tpy = 2,2';6',2″-terpyridine) is representative of the largest known class of water oxidation catalysts. We undertook an extensive spectroscopic analysis of the prototypical 1 water oxidation catalyst and its fastest known analog [Ru(EtO-tpy)(bpy)(H2O)]2+ (2), capable of 10 times faster water oxidation, to investigate the mechanism of action and factors controlling catalytic activity. EPR and resonance Raman spectroscopy did not detect the proposed [RuV═O] intermediate in 1 and 2 but indicated the possible formation of N-oxides. A lag phase was observed prior to O2 evolution, suggesting catalyst modification before the onset of catalysis. The reactive intermediate [Ru(tpy)(bpy-NO)(H2O)]2+ (1-NO; bpy-NO = 2,2'-bipyridine-N-oxide) proposed by combined spectroscopic and DFT analysis was de novo synthesized and demonstrated 100-fold greater catalytic activity than 1. Thus, in situ transient formation of small amounts of the Ru complex with N-oxide ligands can significantly activate single-site Ru-based catalysts. Furthermore, the rate of O2 evolution was found to correlate with the redox potential of the ligand. This observation might assist with rational design of new catalysts.