Methodological quality of behavioural weight loss studies: a systematic review.

This systematic review assessed the methodological quality of behavioural weight loss intervention studies conducted among adults and associations between quality and statistically significant weight loss outcome, strength of intervention effectiveness and sample size. Searches for trials published between January, 2009 and December, 2014 were conducted using PUBMED, MEDLINE and PSYCINFO and identified ninety studies. Methodological quality indicators included study design, anthropometric measurement approach, sample size calculations, intent-to-treat (ITT) analysis, loss to follow-up rate, missing data strategy, sampling strategy, report of treatment receipt and report of intervention fidelity (mean = 6.3). Indicators most commonly utilized included randomized design (100%), objectively measured anthropometrics (96.7%), ITT analysis (86.7%) and reporting treatment adherence (76.7%). Most studies (62.2%) had a follow-up rate > 75% and reported a loss to follow-up analytic strategy or minimal missing data (69.9%). Describing intervention fidelity (34.4%) and sampling from a known population (41.1%) were least common. Methodological quality was not associated with reporting a statistically significant result, effect size or sample size. This review found the published literature of behavioural weight loss trials to be of high quality for specific indicators, including study design and measurement. Identified for improvement include utilization of more rigorous statistical approaches to loss to follow up and better fidelity reporting.

Transportation and retention in outpatient drug abuse treatment programs.

To determine whether certain types of transportation assistance improve outpatient treatment retention beyond thresholds shown to have therapeutic benefits, we analyzed data from 1,144 clients in 22 outpatient methadone maintenance (OMM) programs and 2,031 clients in 22 outpatient drug-free (ODF) programs in the Drug Abuse Treatment Outcomes Study (DATOS), a national, 12-month, longitudinal study of drug abuse treatment programs. Directors' surveys provided information about provision of car, van, or contracted transportation services or individual vouchers/payment for public transportation. Chart-abstracted treatment retention was dichotomized at 365 days for OMM and 90 days for ODF. Separate multivariate hierarchical linear models revealed that provision of car, van, or contracted transportation services improved treatment retention beyond these thresholds for both OMM and ODF, but individual vouchers or payment for public transportation did not. Future research should validate whether car, van, or contracted transportation services improve retention and other treatment outcomes in outpatient drug abuse treatment.

Linkage to medical services in the Drug Abuse Treatment Outcome Study.

BACKGROUND: An episode of substance abuse treatment is an opportunity to link substance-abusing patients to medical care at a time when management of medical problems might stabilize recovery and long-term health. However, little is known about the ability of organizational linkage mechanisms to facilitate the delivery of medical care to this population. OBJECTIVES: The goal of this study was to examine whether organizational linkage mechanisms facilitate medical service utilization in drug abuse treatment programs. RESEARCH DESIGN: This was a prospective secondary analysis of the Drug Abuse Treatment Outcome Study, a national longitudinal study of drug abuse treatment programs and their patients from 1991 to 1993. Hierarchical linear models evaluated the effect of on-site delivery, formal and informal referral, case management emphasis, and transportation on the log-transformed number of medical visits at the 1-month in-treatment patient interview. MEASURES: Program directors' surveys provided organizational information, including the linkage mechanism used to deliver medical care. Patients reported the number of medical visits during the first month of drug abuse treatment. RESULTS: Exclusive on-site delivery increased medical utilization during the first month of drug abuse treatment (beta estimate, 0.22; standard error [SE], 0.06; P <0.001). Transportation services also increased 1-month medical utilization (beta estimate, 0.13; SE, 0.03; P <0.001). CONCLUSIONS: Exclusive on-site delivery of medical services increased drug abuse treatment patients' utilization of medical services in the first month of treatment. Transportation assistance warrants strong policy consideration as a facilitator of medical service delivery. Future research should clarify whether program-level linkage to medical services improves the patient-level outcomes of drug abuse treatment.

Stimulatory regulation of the large-conductance, calcium-activated potassium channel by G proteins in bovine adrenal chromaffin cells.

G proteins regulate the electrical activity of various cells through their actions on membrane ion channels. In the present study, the effect of G proteins was examined on unitary, large conductance (BK), Ca(2+)-activated K+ channels measured in excised, inside-out patches of membrane obtained from cultured bovine adrenal chromaffin cells. Cytoplasmic application of either guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) or AlF-4 to stimulate G proteins resulted in a > 4-fold increase in the open probability of the BK channel measured at +40 mV in the presence of a 1 microM concentration of Ca2+. A similar stimulatory regulation was observed after the addition of an activated, mixed Gi/Go alpha preparation. The increase in the open probability during G protein stimulation was associated with a large reduction in the duration of a long closed state of the channel and could be observed in the presence of a protein kinase inhibitor. The half-maximal voltage required for steady state activation of the BK channel decreased from +63 mV to +48 mV in the presence of GTP gamma S. In addition, the half-maximal Ca2+ concentration required for channel opening was reduced from 11.7 microM in control measurements to 1.3 microM during regulation by GTP gamma S. Thus, G proteins increase the open probability of the chromaffin BK Ca(2+)-activated K+ channel by shifting the voltage dependence of channel gating to more negative potentials and by enhancing the affinity of the channel for Ca2+. Stimulatory regulation may provide a compensatory mechanism for decreasing the action potential duration during secretagogue-mediated exocytosis.