Using a Group Stimulus Preference Assessment to Design an Effective Group Contingency.

Unlabelled: The purpose of this study was to extend the limited research on group stimulus preference assessment (SPA) procedures. The study occurred in two sections of a middle school special education classroom and included 20 students with multi-categorical disabilities. A paired stimulus group SPA was used to identify a preference hierarchy for each class, and results were validated using single case designs in which baseline conditions were compared to group contingency conditions with alternating sessions of the highest-preferred (high-p) and lowest-preferred (low-p) consequences.

Using Subthreshold Vibratory Stimulation During Poststroke Rehabilitation Therapy: A Case Series.

Subthreshold vibratory stimulation to the paretic wrist has been shown to prime the sensorimotor cortex and improve 2-week upper extremity (UE) therapy outcomes. The objective of this work was to determine feasibility, safety, and preliminary efficacy of the stimulation over a typical 6-week therapy duration. Four chronic stroke survivors received stimulation during 6-week therapy.

Saposin B-dependent reconstitution of arylsulfatase A activity in vitro and in cell culture models of metachromatic leukodystrophy.

Arylsulfatase A (ASA) catalyzes the intralysosomal desulfation of 3-O-sulfogalactosylceramide (sulfatide) to galactosylceramide. The reaction requires saposin B (Sap B), a non-enzymatic proteinaceous cofactor which presents sulfatide to the catalytic site of ASA. The lack of either ASA or Sap B results in a block of sulfatide degradation, progressive intralysosomal accumulation of sulfatide, and the fatal lysosomal storage disease metachromatic leukodystrophy.

Saposin B binds and transfers phospholipids.

Saposin B (Sap B) is a member of a family of four small glycoproteins, Sap A, B, C, and D. Like the other three saposins, Sap B plays a physiological role in the lysosomal degradation of sphingolipids (SLs). Although the interaction of Sap B with SLs has been investigated extensively, that with the main membrane lipid components, namely phospholipids and cholesterol (Chol), is scarcely known.

A novel mass spectrometric assay for the cerebroside sulfate activator protein (saposin B) and arylsulfatase A.

A mass spectrometric method is described for monitoring cerebrosides in the presence of excess concentrations of alkali metal salts. This method has been adapted for use in the assay of arylsulfatase A (ASA) and the cerebroside sulfate activator protein (CSAct or saposin B). Detection of the neutral glycosphingolipid cerebroside product was achieved via enhancement of ionization efficiency in the presence of lithium ions.

Characterization of a recombinant molecule covalently indistinguishable from human cerebroside-sulfate activator protein (CSAct or Saposin B).

Humans deficient in the cerebroside-sulfate activator protein (CSAct or Saposin B) are unable to catabolize sulfatide and other glycosphingolipids leading to their accumulation and neurodegenerative disease. Clinically this usually manifests as a form of metachromatic leukodystrophy (MLD). CSAct is a small water-soluble glycoprotein that apparently functions in the lysosome to solubilize sulfatide and other lipids enabling their interaction with soluble lysosomal hydrolases.

Crystal structure of saposin B reveals a dimeric shell for lipid binding.

Saposin B is a small, nonenzymatic glycosphingolipid activator protein required for the breakdown of cerebroside sulfates (sulfatides) within the lysosome. The protein can extract target lipids from membranes, forming soluble protein-lipid complexes that are recognized by arylsulfatase A. The crystal structure of human saposin B reveals an unusual shell-like dimer consisting of a monolayer of alpha-helices enclosing a large hydrophobic cavity.

Expression, purification, crystallization, and preliminary X-ray analysis of recombinant human saposin B.

Saposin B (also known as cerebroside sulfate activator or CSAct) is a small non-enzymatic glycoprotein required for the breakdown of cerebroside sulfates (sulfatides) in lysosomes. Saposin B contains three intramolecular disulfide bridges, exists as a dimer and is remarkably heat, protease, and pH stable. We have expressed the protein in a thioredoxin reductase deficient strain of Escherichia coli and purified the protein by heat treatment, followed by ion-exchange, gel filtration, and hydrophobic interaction chromatographies.

Arylsulfatase a is present on the pig sperm surface and is involved in sperm-zona pellucida binding.

We have previously described the affinity of a pig sperm surface protein, P68, to mammalian zonae pellucidae (ZP). In this report, we identified P68 as arylsulfatase A (AS-A) based on the presence of P68 tryptic peptide sequences in the pig testis AS-A cDNA sequence. Our objective was to demonstrate the presence of AS-A on the sperm surface and to elucidate its role in ZP binding.

Binding of arylsulfatase A to mouse sperm inhibits gamete interaction and induces the acrosome reaction.

We have shown previously that male germ cell-specific sulfoglycolipid, sulfogalactosylglycerolipid (SGG), is involved in sperm-zona pellucida binding, and that SGG and its desulfating enzyme, arylsulfatase A (AS-A), coexist in the same sperm head area. However, AS-A exists at a markedly low level in sperm as compared to SGG (i.e.

A monoclonal antibody that induces neuronal apoptosis binds a metastasis marker.

The cell surface molecules controlling apoptosis in cortical neurons are largely unknown. A monoclonal antibody was derived that induces cultured neocortical neurons to undergo apoptosis. A Fab fragment of the antibody, however, lacked the ability to induce cell death.

Structure of the asparagine-linked sugar chains of porcine kidney and human urine cerebroside sulfate activator protein.

The specific sugar residues and their linkages in the oligosaccharides from pig kidney and human urine cerebroside sulfate activator proteins (saposin B), although previously hypothesized, have been unambiguously characterized. Exhaustive sequential exoglycosidase digestion of the trimethyl-p-aminophenyl derivatives, followed by either matrix-assisted laser desorption/ionization and/or mass spectrometry, was used to define the residues and their linkages. The oligosaccharides were enzymatically released from the proteins by treatment with peptidyl-N-glycosidase F and separated from the proteins by reversed-phase high-performance liquid chromatography (HPLC).

Comparative lipid binding study on the cerebroside sulfate activator (saposin B).

Cerebroside sulfate activator (saposin B) is a small protein involved in glycosphingolipid metabolism. It binds certain membrane lipids, making them available to water-soluble enzymes. Defects in this protein are responsible for a form of metachromatic leukodystropy, a progressive neurodegenerative condition.

Methionine oxidation within the cerebroside-sulfate activator protein (CSAct or Saposin B).

The cerebroside-sulfate activator protein (CSAct or Saposin B) is a small water-soluble glycoprotein that plays an essential role in the metabolism of certain glycosphingolipids, especially sulfatide. Deficiency of CSAct in humans leads to sulfatide accumulation and neurodegenerative disease. CSAct activity can be measured in vitro by assay of its ability to activate sulfatide-sulfate hydrolysis by arylsulfatase A.

Disulfide connectivity in cerebroside sulfate activator is not necessary for biological activity or alpha-helical content but is necessary for trypsin resistance and strong ligand binding.

Cerebroside sulfate activator (CSAct) protein is exceptionally resistant to heat denaturation and proteolytic digestion. Although water soluble the protein binds membrane-associated lipids. Its biological role is thought to be to transfer certain lipids between membranes and to facilitate their catabolism in the lysosomes.

Hydrogen-deuterium exchange signature of porcine cerebroside sulfate activator protein.

Hydrogen-deuterium exchange can be a sensitive indicator of protein structural integrity. Comparisons were made between cerebroside sulfate activator protein (CSAct) in the native state and after treatment with guanidine hydrochloride plus dithiothreitol. Native protein has three internal disulfide bonds and treated protein has no internal disulfide bonds.

Analysis of sulfatide from rat cerebellum and multiple sclerosis white matter by negative ion electrospray mass spectrometry.

The accumulation of sulfatide (sulfatogalactosyl cerebroside) and changes in the sulfatide species present have been examined in the cerebellum of day 6-32 aged rats and in multiple sclerosis (MS) tissue samples. Negative ion electrospray mass spectrometry with daughter and parent ion analyses were used to distinguish the fatty acyl character in the amide linkage of sulfatide; measurement was done by selected ion and multiple reaction monitoring of individually identified sulfatide molecules. Sulfatide accumulation in rat cerebellum shows that 18:0- and hydroxylated 18:0-sulfatide are the first sulfatide molecules detectable.

Preparation of the cerebroside sulfate activator (CSAct or saposin B) from human urine.

The purification of cerebroside sulfate activator (CSAct) or saposin B from pooled human urine is described. Urinary proteins are concentrated by ammonium sulfate precipitation. A suspension of the precipitate is heat-treated and the heat-stable proteins are fractionated through a series of chromatographic steps.

Cerebroside sulfate activator protein (Saposin B): chromatographic and electrospray mass spectrometric properties.

Cerebroside sulfate activator protein is a small, heat-stable protein that is exceptionally resistant to proteolytic attack. This protein is essential for the catabolism of cerebroside sulfate and several other glycosphingolipids. Protein purified from pig kidney and human urine was extensively characterized by reversed-phase liquid chromatography and electrospray mass spectrometry.

Porcine cerebroside sulfate activator (saposin B) secondary structure: CD, FTIR, and NMR studies.

Cerebroside sulfate activator protein (CSAct or saposin B) is one of a group of heat stable, low-molecular-weight proteins that appear to share a common structural motif. These have been referred to as saposin-like proteins and are thought to share a multiple amphipathic helical barrel structure with a conserved pattern of disulfide linkages. Porcine kidney CSAct was prepared in high purity and consisted of three major glycosylated subforms.

An enzyme immunoassay for neuron-specific enolase in cerebrospinal fluid.

A direct (as opposed to competitive) enzyme immunoassay (EIA) was developed to detect neuron-specific enolase (NSE) in cerebrospinal fluid (CSF). Most common methods of evaluating NSE levels have utilized radioimmunoassay. These are highly sensitive, but cannot be employed in laboratories not equipped or licensed for the use of radioisotopes.

Neuroamine related compounds in the CSF of hydrocephalic rabbits.

The effects of neonatal hydrocephalus on the levels of tyrosine, tryptophan, 5-hydroxyindoleacetic acid (5-HIAA), and homovanillic acid (HVA) in CSF were determined by high-performance liquid chromatography (HPLC) with fluorometric detection in normal and chronically hydrocephalic rabbits. The hydrocephalic rabbits showed a highly significant increase in both the serotonin metabolite 5-HIAA and the dopamine metabolite HVA. There were no significant effects of the hydrocephalus on either tyrosine or tryptophan levels.

Isolation, characterization, and proteolysis of human prosaposin, the precursor of saposins (sphingolipid activator proteins).

Prosaposin contains separate domains in tandem for four saposins, A, B, C, and D. These mature saposins are produced by limited proteolysis of prosaposin. They are involved in lysosomal hydrolysis of GM1 ganglioside, gluco- and galactocerebrosides, sulfatides, and sphingomyelin and other sphingolipids.

The effect of carbohydrate removal on stability and activity of saposin B.

Saposin B is involved in the hydrolysis of sulfatides, GM1 ganglioside, globotriaosylceramide, and several other sphingolipids and glycerolipids by lysosomal hydrolases. Saposin B is one of four small glycoproteins (saposins) derived from prosaposin. The carbohydrate chain of saposin B was removed and deglycosylated saposin B was characterized and compared with native saposin B.

Porcine cerebroside sulfate activator: further structural characterization and disulfide identification.

Cerebroside sulfate activator (CS-Act) is a small compact protein which binds and solubilizes certain glycosphingolipids. Following the recent publication of the purification and preliminary sequence of pig kidney CS-Act [Fluharty, A.L.