Biochemical and functional characterization of a recombinant GTPase, Rab5, and two of its mutants.

Biochemical, structural, and functional properties of Rab5 wild-type (WT) protein were compared with those of Q79L and N133I mutants. The detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate increased guanine nucleotide binding to Rab5 WT approximately 10-fold. The single-step catalytic rate of Rab5 WT exceeded that of Q79L 12.

Regional variation in service system performance: comparing the perceptions of key stakeholders.

Area variation studies rarely focus on perceptions of service system performance in their comparative analyses. Using an instrument designed specifically for assessing key stakeholders' perceptions of the performance of mental health service delivery systems, this study compared three areas in Massachusetts that differ significantly with regard to service system structure and resource allocation. Despite these differences, key stakeholders' perceptions of service adequacy, availability, quality, and coordination did not vary substantially, although the findings suggest that to some extent organizational structure may have more effect than resource availability and allocation on perceptions of key stakeholders within the three systems.

Acute and chronic psychiatric care: establishing boundaries.

Despite advances in psychiatry, a proportion of those with mental illness have episodes of severe illness, and a few of these patients may attain only partial recovery. In this respect, mental illness is similar to physical illness and systems of acute and chronic care are essential. As mental health care financing and delivery systems undergo further flux and reform, we will require clear, consensually developed definitions of levels of care, especially because of the complexities created by a legacy of a 2-tiered, public and private mental health system.

The imperative of outcome assessment in psychiatry.

This report describes the current conceptualization of outcome assessment in psychiatry and focuses on how assessment instruments can be built into psychiatric facility-based practice. First, the domains of clinical assessment are outlined, with an emphasis on three elements: level of psychiatric symptoms, clinical functioning, and patient satisfaction. Examples of outcome instruments then are provided as well as the elements of their successful implementation.

Evaluating mental health care reform: including the clinician, client, and family perspective.

This article suggests one direction that theory building might take to develop a stronger conceptual foundation needed to test the effect on clients of reforms in the financing and organization of mental health care delivery systems. The authors recommend that health status outcomes be measured from three perspectives: the client, who can best report his or her own subjective experience of illness; the clinician, who is the best source of information about the client's disease; and the family, which is the best source of information about the effects on members' health status of caring for a mentally ill family member. The authors also recommend that measurement of health status should be multidimensional.

A comparison of for-profit and not-for-profit hospitals on the cost of mental health admissions.

The debate around health reform has raised questions about costs of care and the nature of competition in the delivery of care. This study examines whether the profit incentive leads to more-cost-efficient delivery of psychiatric and substance-abuse care. The data are from paid claims for 561 psychiatric and substance-abuse admissions in 1985-1987 from two very large national corporations with generous indemnity health plans that included nondiscriminatory mental health benefits.

Neutrophil recruitment in Clostridium difficile toxin A enteritis in the rabbit.

Neutrophil infiltration is a prominent feature of Clostridium difficile-associated enteritis and colitis. The aim of this study was to examine the importance of neutrophil recruitment and neutrophil-mediated tissue damage in C. difficile toxin A-induced enteritis.

Identification of ras and ras-related low-molecular-mass GTP-binding proteins associated with rat lung lamellar bodies.

Recent evidence from genetic experiments in yeast and from studies using guanosine triphosphate (GTP) analogues in mammalian cells suggests a key role for low-molecular-mass GTP-binding proteins (LMM-GBPs) (Mr 19 to 28 kD) in processes of intracellular vesicular sorting and secretion. Assembly and exocytosis of the lamellar body (LB), the secretory organelle of the pulmonary alveolar type 2 pneumocyte, may be regulated by LMM-GBPs. We used [alpha-32P]GTP binding to Western blotted proteins, ultraviolet crosslinking of [alpha-32P]GTP to membrane proteins, immunoblotting with specific antisera, and botulinum exoenzyme C3-catalyzed ADP ribosylation to detect LMM-GBPs in LB.

Extrapulmonary thoracic restriction (hidebound chest) complicating eosinophilic fasciitis.

Eosinophilic fasciitis (EF) is an unusual disorder characterized by diffuse skin thickening and induration due to inflammation within the deep fascia; visceral involvement is generally mild or absent. A patient with biopsy-proved EF developed progressive respiratory limitation. Physical examination revealed marked induration of the thoracic integument with a severely limited chest wall excursion.

Characterization of rabbit ileal receptors for Clostridium difficile toxin A. Evidence for a receptor-coupled G protein.

The purpose of this study was to characterize the surface receptor for toxin A, the enterotoxin from Clostridium difficile, on rabbit intestinal brush borders (BB) and on rat basophilic leukemia (RBL) cells. Purified toxin A was radiolabeled using a modified Bolton-Hunter method to sp act 2 microCi/micrograms, with retention of full biologic activity. 3H-Toxin A bound specifically to a single class of receptors on rabbit BB and on RBL cells with dissociation constants of 5.

Modification of brain guanine nucleotide-binding regulatory proteins by tryptamine-4,5-dione, a neurotoxic derivative of serotonin.

We have recently characterized a novel oxidation product of serotonin (5-hydroxytryptamine, 5-HT), tryptamine-4,5-dione, which increases 5-HT efflux from striatum and hippocampus and causes selective neuronal death. Exposure of striatal synaptosomes or the major brain guanine nucleotide-binding regulatory proteins Gi and Go to [3H]tryptamine-4,5-dione resulted in the radiolabeling of a major band with an apparent molecular mass equivalent to that of the alpha subunits of Gi and Go (approximately 40,000). The binding of [35S]guanosine-5'-O-(3-thiotriphosphate) ([35S]GTP-gamma-S) to Gi and Go and pertussis toxin-catalyzed [32P]ADP-ribosylation of the G protein alpha subunits were both inhibited in a dose-dependent manner by tryptamine-4,5-dione.

Mechanisms of mastoparan-stimulated surfactant secretion from isolated pulmonary alveolar type 2 cells.

Mastoparan, a tetradecapeptide component of wasp venom, is a potent activator of secretion in a variety of cell types, and has been shown to activate purified G-proteins reconstituted into phospholipid vesicles with a preferential activation of Gi over Gs (Higashijima, T., Uzu, S., Nakajima, T.

Compartmentalization of low molecular mass GTP-binding proteins among neutrophil secretory granules.

Neutrophils contain several distinct classes of secretory granules that may sequentially fuse with the phagosome after the ingestion of particulates, or that may be differentially exocytosed after cellular activation with soluble stimuli. The exocytosis of neutrophil secretory granules has been shown to be GTP-dependent at a step distal to activation of the transductional G proteins. Inasmuch as ras-related low molecular mass GTP-binding proteins have been shown to play regulatory roles in vesicle sorting in the secretory pathway in yeast, the differential mobilization of neutrophil granules might be regulated by distinct GTP-binding proteins.

Subcellular distribution and characterization of GTP-binding proteins in human neutrophils.

The subcellular distribution of GTP binding proteins in human neutrophils and their functional coupling to the N-formylmethionylleucylphenylalanine (FMLP) receptor was characterized to provide insight into mechanisms of cellular activation. Human neutrophils were nitrogen cavitated and fractionated on discontinuous Percoll gradients. Four subcellular fractions were obtained: cytosol, light membranes enriched for plasma membranes, specific granules and azurophilic granules.

GTP-binding proteins in rat liver nuclear envelopes.

Nuclear transport as well as reassembly of the nuclear envelope (NE) after completion of mitosis are processes that have been shown to require GTP and ATP. To study the presence and localization of GTP-binding proteins in the NE, we have combined complementary techniques of [alpha-32P]GTP binding to Western-blotted proteins and UV crosslinking of [alpha-32P]GTP with well-established procedures for NE subfractionation. GTP binding to blotted NE proteins revealed five low molecular mass GTP-binding proteins of 26, 25, 24.

Patterns of service use and costs in model day hospital-in programs in Boston and Tucson.

Patterns of service use and costs in two similar model day hospital-inn programs for psychiatric patients in publicly funded hospitals in Boston and Tucson are compared. Implementation of the programs resulted in cost savings at both sites, although mean annual costs per patient were much lower in Tucson than in Boston. Compared with patients at the Boston site, patients in Tucson had more admissions but shorter stays and fewer days in the program during a 12-month follow-up period.

Low molecular weight GTP-binding proteins are associated with neuronal organelles involved in rapid axonal transport and exocytosis.

Recent evidence suggests that low molecular weight GTP-binding proteins may play important roles in a variety of membrane transport processes. In order to address the question of whether these proteins are involved in transport processes in the nerve axon, we have assessed their presence in rapid transport membranes from rabbit optic nerve. We report the characterization of a group of low molecular weight GTP-binding proteins which are constituents of rapid transport vesicles.

Containing mental health treatment costs through program design: a Massachusetts study.

A single site pre-post study of seriously mentally ill patients treated in a public mental health system shows that annual treatment costs can be substantially reduced with the use of day hospital treatment. Two cohorts of psychiatric patients--282 consecutive admissions to a traditional public inpatient unit in 1980, and 340 consecutive admissions to a combination of inpatient and day hospital care in 1984--were followed 12 months after admission. The substitution of the day hospital is made possible because the facility provided a dormitory residence for those who could not go home at night.

Solubilization and reconstitution of the formylmethionylleucylphenylalanine receptor coupled to guanine nucleotide regulatory protein.

We describe the solubilization, resolution, and reconstitution of the formylmethionylleucylphenylalanine (fMet-Leu-Phe) receptor and guanine nucleotide regulatory proteins (G-proteins). The receptor was solubilized with 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate. Guanine nucleotides decreased the number of high-affinity binding sites and accelerated the rate of dissociation of the receptor-ligand complex, suggesting that the solubilized receptor remained coupled to endogenous G-proteins.

Purification and characterization of the rat liver vasopressin (V1) receptor.

Utilizing a proteoliposome reconstitution system, we have purified the rat liver V1 vasopressin receptor to near homogeneity. The receptor was purified approximately 21,000-fold from rat liver membranes, using differential detergent solubilization, size exclusion gel filtration, lectin affinity, and ion-exchange chromatography. The purified receptor exhibits a Kd of 6 nM, when, prior to solubilization, the membranes were exposed to 1 microM vasopressin.

Identification and purification of a novel G protein from neutrophils.

A novel G protein which appears to couple chemotactic peptide receptors to a polyphosphoinositide phospholipase C has been purified from rabbit neutrophils. Neutrophil membranes were solubilized with sodium cholate and fractionated by successive anion exchange, gel filtration and hydrophobic chromatography. Guanosine-5'-(3-O-thio)triphosphate binding activity was purified 170-fold from the soluble extract.

Origin of urea-soluble protein in the selenite cataract. Role of beta-crystallin proteolysis and calpain II.

Nuclear cataract resulting from an overdose of selenite was characterized by a five-fold increase in nuclear urea-soluble protein. The origin of this urea-soluble protein was examined by two-dimensional electrophoresis, immunoblotting with monospecific antisera against rat lens crystallins, and tryptic mapping. Cataractous urea-soluble protein was primarily composed of insolubilized beta- and gamma-crystallin polypeptides.