Dopamine D(2)/D(3) receptor binding of [(123)I]epidepride in risperidone-treatment chronic MK-801-induced rat schizophrenia model using nanoSPECT/CT neuroimaging.

INTRODUCTION: Epidepride is a compound with an affinity in picomolar range for D2/D3 receptors. The aim of this work was designed to investigate the diagnostic possibility of [(123)I]epidepride imaging platform for risperidone-treatment chronic MK-801-induced rat schizophrenia model. METHODS: Rats received repeated administration of MK-801 (dissolved in saline, i.p., 0.3 mg/kg/day) or saline for 4 weeks. After 1-week administration of MK-801, rats in MK-801+risperidone group received risperidone (0.5 mg/kg/day) intraperitoneally 15 min prior to MK-801 administration for the rest of 3-week treatment. We obtained serial [(123)I]epidepride neuroimages from nanoSPECT/CT and evaluated the alteration of specific binding in striatum and midbrain. RESULTS: Risperidone reversed chronic MK-801-induced decrease in social interaction duration. IHC and ELISA analysis showed consistent results that chronic MK-801 treatment significantly decreased striatal and midbrain D2R expression but repeated risperidone administration reversed the effect of MK-801 treatment. In addition, [(123)I]epidepride nanoSPECT/CT neuroimaging revealed that low specific [(123)I]epidepride binding ratios caused by MK-801 in striatum and midbrain were statistically alleviated after 1- and 2-week risperidone administration, respectively. CONCLUSIONS: We established a rat schizophrenia model by chronic MK-801 administration for 4 weeks. [(123)I]Epidepride nanoSPECT neuroimaging can trace the progressive alteration of D2R expression in striatum and midbrain caused by long-lasting MK-801 treatment. Besides diagnosing illness stage of disease, [(123)I]epidepride can be a useful tool to evaluate therapeutic effects of antipsychotic drug in chronic MK-801-induced rat schizophrenia model.

Regional variation in physician practice pattern: an examination of technical and cost efficiency for treating sinusitis.

OBJECTIVE: An examination of the physician efficiency and resulting cost patterns by region. DATA SOURCES: Virginia Medicaid sinusitis related claims for 1993 were aggregated to physician level (n = 178), and Area Resources File for 1993 was used to identify regions for evaluation. STUDY DESIGN: The best practice performance in the usage of five resources (i.e., primary care physician visits, referral services, emergency room visits, prescriptions, laboratory tests) was identified using Data Envelopment Analysis (DEA). Five regions in Virginia were identified according to regional planning to evaluate the variation in efficiency across these regions. PRINCIPAL FINDINGS: Inefficient physicians consumed significantly more resources and were 48% more costly than efficient physicians. Substantial regional variation was found and mainly attributed to the differences in use of prescriptions and laboratory procedures. Urban-rural discrepancy may explain part of the variation. CONCLUSIONS: As this study reveals the existence of substantial variation in physician efficiency, actions should be taken to minimize the variation that is more affected by personal and structural factors. For example, information on efficient use of resources and corresponding patient outcomes can be disseminated to the attending physicians. Educational workshops can be conducted to allow sharing of experience between efficient and inefficient physicians. Efforts should also be directed to help inefficient physicians to adhere to practice guidelines.

Do primary care physicians or specialists provide more efficient care?

Sinusitis is a common health complaint and expenditures for its treatment are high; thus, it is necessary to promote efficient practice behaviours in managing patient care. This study compares resource utilization between primary care physicians and specialists in the treatment of Medicaid sinusitis patients in Virginia. Physician-level data from Virginia Medicaid claim files for 1993 were analysed. The efficiency frontier, representing the best achievable performance in the use of resources for treating sinusitis, is identified using Data Envelopment Analysis. Resource utilization (primary care physician visits, specialist visits, emergency room usage, prescriptions and laboratory tests) and corresponding costs are compared between generalists and otolaryngologists. It was concluded from this study that there are no discernible differences in technical efficiency between generalists and specialists in the treatment of sinusitis. Nevertheless, otolaryngologists are found to be more costly than generalists in treating sinusitis. Variation in both caseload and patient mix might explain variation in use of resources.

Recent determinants of new entry of HMOs into a Medicare risk contract: a diversification strategy.

This study provides knowledge of more recent entry of health maintenance organizations (HMOs) into the Medicare risk program than earlier analyses. Based on a diversification framework, this study examines new market entry from three dimensions: attractiveness of the market, market area attributes, and organizational attributes. The analysis uses a 1994-1995 cross-sectional, lagged time sample with 440 HMOs that did not have a Medicare risk contract as of January 1994; it defines an HMO's market as its service area. HMO enrollment growth in the market, individual HMO enrollment size, and adjusted average per capita cost (AAPCC) rates are found to be significant in predicting new market entry.

Organizational and market determinants of HMOs' performance of preventive practices.

This study validates the measurements of performance of preventive practices and identifies organizational and market factors that affect variations in the preventive care practices of health maintenance organizations (HMOs). Confirmatory factor analysis was used to assess HMO performance, reflecting the rates of five preventive practice services. A structural equation model of the preventive practice performance of HMOs was evaluated. It was discovered that HMOs that employ more board-certified primary care practitioners have a higher rate of preventive care practices and that market competition and market forces do not influence the variation in HMO preventive care practices.

Strategic hospital alliances: impact on financial performance.

Acute care hospitals have increasingly been forming local strategic hospital alliances (SHAs), which consume considerable resources in forming and may affect the competitiveness of provider markets. This research shows that SHAs and market factors, which have been perceived to be threats to hospitals, are related to hospitals' financial performance. Among the findings are that SHA members have higher net revenues but that they are not more effective at cost control. Nor do the higher net revenues result in higher cash flow. However, increasing SHA penetration in a market is related to lower net revenues per case. In addition, the penetration of private health maintenance organizations in markets is associated with lower revenues and expenses.