Creation of an international registry to support discovery in schwannomatosis

Schwannomatosis is a tumor suppressor syndrome that causes multiple tumors along peripheral nerves. Formal diagnostic criteria were first published in 2005. Variability in clinical presentation and a relative lack of awareness of the syndrome have contributed to difficulty recognizing affected individuals and accurately describing the natural history of the disorder. Many critical questions such as the mutations underlying schwannomatosis, genotype-phenotype correlations, inheritance patterns, pathologic diagnosis of schwannomatosis-associated schwannomas, tumor burden in schwannomatosis, the incidence of malignancy, and the effectiveness of current, or new treatments remain unanswered. A well-curated registry of schwannomatosis patients is needed to facilitate research in field. An international consortium of clinicians and scientists across multiple disciplines with expertise in schwannomatosis was established and charged with the task of designing and populating a schwannomatosis patient registry. The International Schwannomatosis Registry (ISR) was built around key data points that allow confirmation of the diagnosis and identification of potential research subjects to advance research to further the knowledge base for schwannomatosis. A registry with 389 participants enrolled to date has been established. Twenty-three additional subjects are pending review. A formal process has been established for scientific investigators to propose research projects, identify eligible subjects, and seek collaborators from ISR sites. Research collaborations have been created using the information collected by the registry and are currently being conducted. The ISR is a platform from which multiple research endeavors can be launched, facilitating connections between affected individuals interested in participating in research and researchers actively investigating a variety of aspects of schwannomatosis. © 2016 Wiley Periodicals, Inc.

Development of enzymatic conjugation and sulfation of bile acids in hamster liver

In vitro levels of enzyme activity were measured in liver from fetal and developing hamsters to study the fetal immaturity and postnatal development of bile acid conjugation and sulfation. Sulfation and conjugation were measured in the same animals. Partial reactions of bile acid conjugation were assayed independently; sulfation of conjugated and unconjugated lithocholate was measured separately. From 3 days before to 3 days after birth, specific activity for sulfation of lithocholate and lithocholate conjugates was similar; lithocholate sulfation was 80% of adult levels. In older hamsters, specific activity for sulfation of lithocholate conjugates was significantly higher than that for lithocholate. Specific activities of both partial reactions of bile acid conjugation were 12% of adult levels from 3 days before to 3 days after birth. Thereafter both activities increased together; the ratio of glycine to taurine-dependent conjugation was similar at all ages. The data suggest early development of a separate mechanism for lithocholate sulfation. Enzymes catalyzing bile acid conjugation and sulfation of bile acid conjugates exhibit maximal development after birth.

Purification and characterization of bile acid-CoA:amino acid N-acyltransferase from rat liver

An in vitro study of bile acid-CoA:amino acid N-acyltransferase activity of rat liver was undertaken in order to determine whether separate amino acid-specific enzymes catalyzed the formation of glycine and taurine conjugates of bile acids as postulated by others. Polyacrylamide gel electrophoresis of 200-fold purified enzyme localized the glycine- and taurine-dependent activities to a single band. Both activities were optimal at pH 7.8 and showed similar loss of activity at pH 6.0, pH 9.0, in the presence of 5,5'-dithiobis(2-nitrobenzoic acid), and at temperatures exceeding 50 degrees. With the purified fraction, Km for glycine was 31 mM and Km for taurine was 0.8 mM. Km for several bile acid-CoA substrates was approximately 20 micron and independent of the amino acid acceptor. Only amino acids with terminal alpha- or beta-amino groups were active as acyl acceptors. Acyl donors were limited to bile acid-CoA derivatives. The data support the conclusion that the rat has a single bile acid-CoA:amino acid N-acyltransferase. The substrate kinetics are consistent with previous observations that taurine conjugates predominate in rat bile at normal hepatocellular concentrations of glycine and taurine.