No abstract

Acid ␤-glucosidase (GCase) is a 497-amino acid, membrane-associated lysosomal exo-␤-glucosidase whose defective activity leads to the Gaucher disease phenotypes. To move toward a structure/ function map for disease mutations, 52 selected single amino acid substitutions were introduced into GCase, expressed in an insect cell system, purified, and characterized for basic kinetic, stability, and activator response properties. The variant GCases from Gaucher disease patients and selected variant GCases from the mouse had decreased relative k cat and differential effects on active site binding and/or attachment of mechanism-based covalent (conduritol B epoxide) or reversible (deoxynojirimycin derivatives) inhibitors. A defect in negatively charged phospholipid activation was present in the majority of variant GCases but was increased in two, N370S and V394L. Deficits in saposin C enhancement of k cat were present in variant GCases involving residues 48 -122, whereas ϳ2-fold increases were obtained with the L264I GCase. About 50% of variant GCases each had wild-type or increased sensitivity to in vitro cathepsin D digestion. Mapping of these properties onto the crystal structures of GCase indicated wide dispersion of functional properties that can affect catalytic function and stability. Site-directed mutagenesis of cysteine residues showed that the disulfide bonds, Cys 4 -Cys 16 and Cys 18 -Cys 23 , and a free Cys 342 were essential for activity; the free Cys 126 and Cys 248 were not. Relative k cat was highly sensitive to a His substitution at Arg 496 but not at Arg 495 . These studies and high phylogenetic conservation indicate localized and general structural effects of Gaucher disease mutations that were not obvious from the nature of the amino acid substitution, including those predicted to be nondisruptive (e.g. Val 3 Leu). These results provide initial studies for the engineering of variant GCases and, potentially, molecular chaperones for therapeutic use.

No abstract

The Gaucher Registry permits a comprehensive understanding of the clinical spectrum of GD because of the uniquely large sample size. The Registry will be useful in evaluating the effects of specific therapies in GD and the possible influences of environment, ethnicity, and genotype on the natural history of the disorder.

This elective was successful in attracting students who were more anxious than their peers. Enrolees had higher baseline anxiety levels than their peers. The course decreased anxiety levels. The significant drop in anxiety scores of the study group suggests that this mind-body elective was an effective way to decrease anxiety in these pre-clinical medical students. Decreases in anxiety were sustained 3 months after the course ended, indicating that the benefits of the course may be longlasting.

No abstract

Primary care fields and non-primary care fields were equally affected by career changes due to badmouthing. This study indicates that badmouthing, while pervasive across all disciplines and an unattractive aspect of the educational experience, cannot alone account for the low proportion of graduates choosing primary care careers.

nucleotide alterations. Nucleotide numbering used the A of the ATG translation initiation start site as nucleotide þ1.