Pediatric Langerhans cell histiocytosis: the impact of mutational profile on clinical progression and late sequelae.

Langerhans cell histiocytosis (LCH) is a clonal histiocytic disorder with recurrent mutations of BRAF and MAP2K1, but data on the impact of genetic features on progression and long-term sequelae are sparse. Cases of pediatric LCH with long-term follow-up from our institution were analyzed for mutations in BRAF and MAP2K1 exons 2 and 3 by immunostaining with mutation-specific VE1 antibody, as well as allele-specific PCR and sequencing, respectively. Clinical and follow-up data were obtained from our files and a questionnaire sent to all former patients.

Biomarker evidence for a major preservation pathway of sedimentary organic carbon.

Hydrogenation processes leading from biomolecules to fossil biomarkers in anoxic sediments are crucial for the preservation of organic matter. However, these processes are still poorly understood. The present identification of several reduced carotenoids in recent sediments attests that these processes operate at the earliest stages of diagenesis without structural or stereochemical specificity, implying a nonbiological reduction pathway.

Purification and characterization of CMP-N-acetylneuraminic acid hydroxylase from pig submandibular glands.

N-Glycoloylneuraminic acid (Neu5Gc) is synthesized as its CMP-glycoside by the action of CMP-N-acetylneuraminic acid (CMP-Neu5Ac) hydroxylase. This enzyme is a soluble cytochrome b5-dependent monooxygenase and has been purified to apparent homogeneity from pig submandibular glands by precipitation with N-cetyl-N,N,N-trimethylammonium bromide and fractionation on Q-Sepharose, Cibacron Blue 3GA-Agarose, Reactive Brown 10-Agarose, Hexyl-Agarose and Superose S.12.

Purification, characterization and reconstitution of CMP-N-acetylneuraminate hydroxylase from mouse liver.

CMP-N-acetylneuraminate hydroxylase was isolated from mouse liver high speed supernatant with a yield of 0.4% and an apparent 1000-fold purification. The enzyme is a monomeric protein with a molecular weight of 66 kDa, as determined by gel filtration and SDS-PAGE.

CMP-N-acetylneuraminic acid hydroxylase from mouse liver and pig submandibular glands. Interaction with membrane-bound and soluble cytochrome b5-dependent electron transport chains.

In this report, the nature of the protein components involved in the functioning of cytidine-5'-monophosphate-N-acetylneuraminic acid (CMP-Neu5 Ac) hydroxylase in high-speed supernatants of mouse liver has been investigated. Fractionation and reconstitution experiments showed that this enzyme system consists of NADH-cytochrome b5 reductase, cytochrome b5 and a 56-kDa terminal electron acceptor having the CMP-Neu5 Ac hydroxylase activity. This enzyme system is extracted in a soluble protein fraction; however, the amphipathic, usually membrane-associated, forms of cytochrome b5 and the reductase were found to predominate and are presumably the forms which support the turnover of the hydroxylase in vivo.