Misassembly of full-length Disrupted-in-Schizophrenia 1 protein is linked to altered dopamine homeostasis and behavioral deficits.

Disrupted-in-schizophrenia 1 (DISC1) is a mental illness gene first identified in a Scottish pedigree. So far, DISC1-dependent phenotypes in animal models have been confined to expressing mutant DISC1. Here we investigated how pathology of full-length DISC1 protein could be a major mechanism in sporadic mental illness. We demonstrate that a novel transgenic rat model, modestly overexpressing the full-length DISC1 transgene, showed phenotypes consistent with a significant role of DISC1 misassembly in mental illness. The tgDISC1 rat displayed mainly perinuclear DISC1 aggregates in neurons. Furthermore, the tgDISC1 rat showed a robust signature of behavioral phenotypes that includes amphetamine supersensitivity, hyperexploratory behavior and rotarod deficits, all pointing to changes in dopamine (DA) neurotransmission. To understand the etiology of the behavioral deficits, we undertook a series of molecular studies in the dorsal striatum of tgDISC1 rats. We observed an 80% increase in high-affinity DA D2 receptors, an increased translocation of the dopamine transporter to the plasma membrane and a corresponding increase in DA inflow as observed by cyclic voltammetry. A reciprocal relationship between DISC1 protein assembly and DA homeostasis was corroborated by in vitro studies. Elevated cytosolic dopamine caused an increase in DISC1 multimerization, insolubility and complexing with the dopamine transporter, suggesting a physiological mechanism linking DISC1 assembly and dopamine homeostasis. DISC1 protein pathology and its interaction with dopamine homeostasis is a novel cellular mechanism that is relevant for behavioral control and may have a role in mental illness.

Amelioration of relapsing polychondritis in a child treated with oral collagen.

Relapsing polychondritis (RP) is a disease characterized by inflammation and the destruction of cartilage. The detection of antibodies to native type II collagen (CII) in the sera of some patients with relapsing polychondritis suggests that autoimmunity to this cartilage specific protein plays a role in the pathogenesis of the disease. RP is so rare that controlled therapeutic trials have not been carried out. We describe herein a child with RP who had amelioration of symptoms and a deviation in the cellular immune response to CII after being treated with daily oral CII as a toleragen.

Sphingomyelin-enriched microdomains at the Golgi complex.

Sphingomyelin- and cholesterol-enriched microdomains can be isolated as detergent-resistant membranes from total cell extracts (total-DRM). It is generally believed that this total-DRM represents microdomains of the plasma membrane. Here we describe the purification and detailed characterization of microdomains from Golgi membranes. These Golgi-derived detergent-insoluble complexes (GICs) have a low buoyant density and are highly enriched in lipids, containing 25% of total Golgi phospholipids including 67% of Golgi-derived sphingomyelin, and 43% of Golgi-derived cholesterol. In contrast to total-DRM, GICs contain only 10 major proteins, present in nearly stoichiometric amounts, including the alpha- and beta-subunits of heterotrimeric G proteins, flotillin-1, caveolin, and subunits of the vacuolar ATPase. Morphological data show a brefeldin A-sensitive and temperature-sensitive localization to the Golgi complex. Strikingly, the stability of GICs does not depend on its membrane environment, because, after addition of brefeldin A to cells, GICs can be isolated from a fused Golgi-endoplasmic reticulum organelle. This indicates that GIC microdomains are not in a dynamic equilibrium with neighboring membrane proteins and lipids. After disruption of the microdomains by cholesterol extraction with cyclodextrin, a subcomplex of several GIC proteins including the B-subunit of the vacuolar ATPase, flotillin-1, caveolin, and p17 could still be isolated by immunoprecipitation. This indicates that several of the identified GIC proteins localize to the same microdomains and that the microdomain scaffold is not required for protein interactions between these GIC proteins but instead might modulate their affinity.

Proof and policy from medical research evidence.

When judging the benefits and harms of health care and predicting patient prognosis, clinicians, researchers, and others must consider many types of evidence. Medical research evidence is part of the required knowledge base, and practitioners of evidence-based medicine must attempt to integrate the best available clinical evidence from systematic research with health professionals' expertise and patients' rights to be informed about diagnostic and therapeutic options available to them. Judging what constitutes sound evidence can be difficult because of, among other things, the sheer quantity, diversity, and complexity of medical evidence available today; the various scientific methods that have been advanced for assembling, evaluating, and interpreting such information; and the guides for applying medical research evidence to individual patients' situations. Recommendations based on sound research can then be brought forward as either guidelines or standards, and criteria exist by which valid guidelines and standards can be developed and promulgated. Nonetheless, gaps and deficiencies exist in current guidelines and in the methods for finding and synthesizing evidence. Interpreting and judging medical research involves subjective, not solely explicit, processes. Thus, developments in evidence-based medicine are an aid, but not a panacea, for definitively establishing benefits and harms of medical care, and the contributions that medical research evidence can make in any clinical or legal situation must be understood in a context in which judgment and values, understanding of probability, and tolerance for uncertainty all play a role.

Current methods of the US Preventive Services Task Force: a review of the process.

The U.S. Preventive Services Task Force (USPSTF/Task Force) represents one of several efforts to take a more evidence-based approach to the development of clinical practice guidelines. As methods have matured for assembling and reviewing evidence and for translating evidence into guidelines, so too have the methods of the USPSTF. This paper summarizes the current methods of the third USPSTF, supported by the Agency for Healthcare Research and Quality (AHRQ) and two of the AHRQ Evidence-based Practice Centers (EPCs). The Task Force limits the topics it reviews to those conditions that cause a large burden of suffering to society and that also have available a potentially effective preventive service. It focuses its reviews on the questions and evidence most critical to making a recommendation. It uses analytic frameworks to specify the linkages and key questions connecting the preventive service with health outcomes. These linkages, together with explicit inclusion criteria, guide the literature searches for admissible evidence. Once assembled, admissible evidence is reviewed at three strata: (1) the individual study, (2) the body of evidence concerning a single linkage in the analytic framework, and (3) the body of evidence concerning the entire preventive service. For each stratum, the Task Force uses explicit criteria as general guidelines to assign one of three grades of evidence: good, fair, or poor. Good or fair quality evidence for the entire preventive service must include studies of sufficient design and quality to provide an unbroken chain of evidence-supported linkages, generalizable to the general primary care population, that connect the preventive service with health outcomes. Poor evidence contains a formidable break in the evidence chain such that the connection between the preventive service and health outcomes is uncertain. For services supported by overall good or fair evidence, the Task Force uses outcomes tables to help categorize the magnitude of benefits, harms, and net benefit from implementation of the preventive service into one of four categories: substantial, moderate, small, or zero/negative. The Task Force uses its assessment of the evidence and magnitude of net benefit to make a recommendation, coded as a letter: from A (strongly recommended) to D (recommend against). It gives an I recommendation in situations in which the evidence is insufficient to determine net benefit. The third Task Force and the EPCs will continue to examine a variety of methodologic issues and document work group progress in future communications.

Screening and treating adults for lipid disorders.

CONTEXT: Screening and treatment of lipid disorders in people at high risk for future coronary heart disease (CHD) events has gained wide acceptance, especially for patients with known CHD, but the proper role in people with low to medium risk is controversial. OBJECTIVE: To examine the evidence about the benefits and harms of screening and treatment of lipid disorders in adults without known cardiovascular disease for the U.S. Preventive Services Task Force. DATA SOURCES: We identified English-language articles on drug therapy, diet and exercise therapy, and screening for lipid disorders from comprehensive searches of the MEDLINE database from 1994 through July 1999. We used published systematic reviews, hand searching of relevant articles, the second Guide to Clinical Preventive Services, and extensive peer review to identify important older articles and to ensure completeness. DATA SYNTHESIS: There is strong, direct evidence that drug therapy reduces CHD events, CHD mortality, and possibly total mortality in middle-aged men (35 to 65 years) with abnormal lipids and a potential risk of CHD events greater than 1% to 2% per year. Indirect evidence suggests that drug therapy is also effective in other adults with similar levels of risk. The evidence is insufficient about benefits and harms of treating men younger than 35 years and women younger than 45 years who have abnormal lipids but no other risk factors for heart disease and low risk for CHD events (less than 1% per year). Trials of diet therapy for primary prevention have led to long-term reductions in cholesterol of 3% to 6% but have not demonstrated a reduction in CHD events overall. Exercise programs that maintain or reduce body weight can produce short-term reductions in total cholesterol of 3% to 6%, but longer-term results in unselected populations have found smaller or no effect. To identify accurately people with abnormal lipids, at least two measurements of total cholesterol and high-density lipoprotein cholesterol are required. The role of measuring triglycerides and the optimal screening interval are unclear from the available evidence. CONCLUSIONS: On the basis of the effectiveness of treatment, the availability of accurate and reliable tests, and the likelihood of identifying people with abnormal lipids and increased CHD risk, screening appears to be effective in middle-aged and older adults and in young adults with additional cardiovascular risk factors.

Applying cognitive design principles to formatting HRQOL instruments.

Researchers developing or using health-related quality of life (HRQOL) instruments can benefit from knowledge of state-of-the-art formatting methods for self-administered questionnaires. Three objectives in formatting design are: (1) to reduce errors in respondent navigation through the questionnaire that lead to item non-response and question misinterpretation; (2) to reduce respondent and administrative burden; and (3) to enhance respondent motivation in question answering and compliance with the request to participate. Based on an extensive literature review to identify techniques that have been shown to meet these objectives, we developed specific guidelines for HRQOL instruments concerning all aspects of questionnaire formatting. These guidelines represent well-motivated recommendations for improving HRQOL instruments, although their overall impact has not been empirically tested. We applied the guidelines to several HRQOL instruments that are widely used internationally, and obtained approval from the developers for all formatting changes to their instruments. Applying cognitive design principles and empirically substantiated formatting techniques produces an HRQOL instrument formatting with six critical attributes: simple, consistent, organized, natural, clear and attractive. The present paper contributes to the emerging research literature on the cognitive processes by which respondents answer HRQOL questions and demonstrates how 'cognitive aspects of survey methodology' research can improve HRQOL data collection efforts.