Sooyoung Yoo

White matter abnormalities in drug-naive patients with obsessive-compulsive disorder: a diffusion tensor study before and after citalopram treatment

Objective:  The aim was to investigate the white matter abnormalities of drug‐naïve patients with obsessive–compulsive disorder (OCD) using diffusion tensor‐imaging and the white matter changes in the patients after pharmacotherapy.

MobileMed: A PDA-Based Mobile Clinical Information System

Patient clinical data are distributed and often fragmented in heterogeneous systems, and therefore the need for information integration is a key to reliable patient care. Once the patient data are orderly integrated and readily available, the problems in accessing the distributed patient clinical data, the well-known difficulties of adopting a mobile health information system, are resolved. This paper proposes a mobile clinical information system (MobileMed), which integrates the distributed and fragmented patient data across heterogeneous sources and makes them accessible through mobile devices. The system consists of four main components: a smart interface, an HL7 message server (HMS), a central clinical database (CCDB), and a web server. The smart interface and the HMS work in concert to generate HL7 messages from the existing legacy systems, which essentially send the patient data in HL7 messages to the CCDB to be stored and maintained. The CCDB and the web server enable the physicians to access the integrated up-to-date patient data. By proposing the smart interface approach, we provide a means for effortless implementation and deployment of such systems. Through a performance study, we show that the HMS is reliable yet fast enough to be able to support efficient clinical data communication

Focal eosinophilic infiltration in the liver: radiologic findings and clinical course.

AbstractBackground: We investigated the radiologic findings and clinical course of focal eosinophilic infiltration in the liver. Methods: We retrospectively reviewed computed tomographic (CT) and sonographic scans in 20 patients (18 male, two female; mean age, 50 years) with pathologically or clinically proven focal eosinophilic infiltration in the liver by two experienced radiologists in our institute from August 1995 to June 1999. We also correlated radiologic findings with peripheral eosinophil count. Radiologic and clinical findings during the follow-up (range, 2–49 months; mean, 19.5 months) also were analyzed. Results: Clinical symptoms and signs included abdominal pain (n = 4), easy fatigability (n = 3), weight loss (n = 1), and peripheral eosinophilia (n = 19). Twelve patients were asymptomatic. On sonographic examinations, all lesions were seen as focal, low echoic nodules. On CT, the lesions appeared isoattenuated or low attenuated in the arterial phase and low attenuated in the portal phase, except one case that showed high attenuation in the arterial phase. The margins of most lesions appeared poorly defined. Lesions were single (n = 9) and multiple: two to five (n = 6), six to 10 (n = 3), and more than 10 (n = 2). Each lesion was smaller than 2 cm; only one was 4 cm in diameter. The distribution of the lesion was subcapsular in 14 patients and central in five. Diffuse dissemination was observed in one. Eosinophil-associated abnormality was not present in other abdominal organ in all cases. The peripheral eosinophil count correlated closely with the number but not with the size of lesions. Sixteen patients who had follow-up images showed complete (n = 14) or partial regression of the lesions with a decrease in size (n = 1) or number (n = 1) after 2–22 months (mean, 6.4 months). Conclusion: Focal eosinophilic infiltration in the liver had somewhat characteristic radiologic findings on sonography and CT. In the correct clinical context of peripheral eosinophilia and self-limited course, these radiologic findings may be helpful in differentiating this condition from other focal hepatic lesions.

Semantic concept-enriched dependence model for medical information retrieval

OBJECTIVE In medical information retrieval research, semantic resources have been mostly used by expanding the original query terms or estimating the concept importance weight. However, implicit term-dependency information contained in semantic concept terms has been overlooked or at least underused in most previous studies. In this study, we incorporate a semantic concept-based term-dependence feature into a formal retrieval model to improve its ranking performance. DESIGN Standardized medical concept terms used by medical professionals were assumed to have implicit dependency within the same concept. We hypothesized that, by elaborately revising the ranking algorithms to favor documents that preserve those implicit dependencies, the ranking performance could be improved. The implicit dependence features are harvested from the original query using MetaMap. These semantic concept-based dependence features were incorporated into a semantic concept-enriched dependence model (SCDM). We designed four different variants of the model, with each variant having distinct characteristics in the feature formulation method. MEASUREMENTS We performed leave-one-out cross validations on both a clinical document corpus (TREC Medical records track) and a medical literature corpus (OHSUMED), which are representative test collections in medical information retrieval research. RESULTS Our semantic concept-enriched dependence model consistently outperformed other state-of-the-art retrieval methods. Analysis shows that the performance gain has occurred independently of the concepts explicit importance in the query. CONCLUSION By capturing implicit knowledge with regard to the query term relationships and incorporating them into a ranking model, we could build a more robust and effective retrieval model, independent of the concept importance.

Modeling of brain D2 receptor occupancy-plasma concentration relationships with a novel antipsychotic, YKP1358, using serial PET scans in healthy volunteers

YKP1358 is a novel serotonin (5‐HT2A) and dopamine (D2) antagonist that, in preclinical studies, fits the general profile of an atypical antipsychotic. We conducted a D2 receptor occupancy study with YKP1358 in healthy volunteers using positron emission tomography (PET) to measure the D2 receptor occupancy of YKP1358 and to characterize its relationship to plasma drug concentrations. A single oral dose, parallel group, dose‐escalation (100, 200, and 250 mg) study was performed in 10 healthy male volunteers with the PET radiotracer [11C]raclopride. The D2 receptor occupancy of striatum was measured pre‐dose, and at 2, 5, and 10 h after YKP1358 administration. Serial blood samples were taken for measurement of plasma YKP1358 concentrations. D2 receptor occupancy by YKP1358 increased to 53–83% at 2 h, and then decreased afterwards, ranging from 40–64% at 5 h to 20–51% at 10 h. The YKP1358 dose‐plasma concentration relationship exhibited extensive variability, but there was a good relationship between plasma concentrations and D2 receptor occupancy that was well predicted by a sigmoid Emax model using nonlinear mixed effects modeling. To our knowledge, this is the first study in which the relationship between plasma concentration and the biomarker of D2 receptor occupancy was modeled using nonlinear mixed effects modeling. It is anticipated that these results will be useful in estimating for subsequent studies the initial doses of YKP1358 required to achieve a therapeutically effective range of D2 receptor occupancy.

Electronically implemented clinical indicators based on a data warehouse in a tertiary hospital: Its clinical benefit and effectiveness

OBJECTIVE Assessing and monitoring care and service using clinical indicators (CIs) can allow the measurement of and lead to improvements in the quality of care. However, the management and maintenance of CI data has been shown to be difficult because the data are usually collected and provided manually. In this study, for the purpose of efficient managing quality indicators, a data warehouse (DW)-based CI monitoring system was developed. The clinical effectiveness and efficiency of a DW-based CI monitoring was investigated through several case studies of the systems operation at a tertiary hospital. METHODS This study analyzed the CIs that have been developed over the past 8 years at a 1340-bed tertiary general university hospital in South Korea to improve and monitor the quality of care and patient safety. The hospital was opened as a fully digital hospital in 2003, and the CIs were computerized in 2005 by implementing a DW-based CI monitoring system. We classified the computerized CIs and evaluated the monitoring results for several representative CIs, such as the optimal prescribing of preventive antibiotics, the average length of stay, the mortality rate, and the rehospitalization rate. RESULTS During the development of the system in 2005, 12 of 19 CIs were computerized, and this number gradually increased until 299 of 335 CIs were computerized by 2012. In addition, among the CIs built computationally through the CI task force team, focal CIs subject to monitoring were selected annually, and the results of this monitoring were shared with all of the staff or the related department and its staff. By providing some examples of our CI monitoring results, we showed the feasibility of improving the quality of care, and maintaining the optimum level of patient care with less labor. CONCLUSIONS The results of this study provide evidence regarding the clinical effectiveness and efficiency as well as the systems operation experience of a DW-based CI monitoring system. These findings may aid medical institutions that plan on computerizing CIs with respect to decision and policy making regarding their systems development and operations.

Loss of asymmetry in D2 receptors of putamen in unaffected family members at increased genetic risk for schizophrenia

Objective:  Dopamine dysregulation has been implicated in the pathophysiology of schizophrenia. The present study was performed to examine whether unaffected relatives at high genetic risk of schizophrenia have dopamine dysregulation in comparison with healthy controls.

Development of the Ubiquitous Spaced Retrieval-Based Memory Advancement and Rehabilitation Training Program

Objective The Ubiquitous Spaced Retrieval-based Memory Advancement and Rehabilitation Training (USMART) program was developed by transforming the spaced retrieval-based memory training which consisted of 24 face-to-face sessions into a self-administered program with an iPAD app. The objective of this study was to evaluate the feasibility and efficacy of USMART in elderly subjects with mild cognitive impairment (MCI). Methods Feasibility was evaluated by checking the satisfaction of the participants with a 5-point Likert scale. The efficacy of the program on cognitive functions was evaluated by the Korean version of the Consortium to Establish a Registry for Alzheimers Disease Neuropsychological Assessment Battery before and after USMART. Results Among the 10 participants, 7 completed both pre- and post-USMART assessments. The overall satisfaction score was 8.0±1.0 out of 10. The mean Word List Memory Test (WLMT) scores significantly increased after USMART training after adjusting for age, educational levels, baseline Mini-Mental Status Examination scores, and the number of training sessions (pre-USMART, 16.0±4.1; post-USMART, 17.9±4.5; p=0.014, RM-ANOVA). The magnitude of the improvements in the WLMT scores significantly correlated with the number of training sessions during 4 weeks (r=0.793; p=0.033). Conclusion USMART was effective in improving memory and was well tolerated by most participants with MCI, suggesting that it may be a convenient and cost-effective alternative for the cognitive rehabilitation of elderly subjects with cognitive impairments. Further studies with large numbers of participants are necessary to examine the relationship between the number of training sessions and the improvements in memory function.

Combining relevancy and methodological quality into a single ranking for evidence-based medicine

Evidence-based medicine has recently received a large amount of attention in medical research. To help clinical practices use evidence-based medicine, it should be easy to find the best current evidence that is relevant to the clinical question and has high methodological quality. However, searching for relevant articles and appraising their validity is demanding work for most clinicians. We hypothesize that, through an effective design that addresses the two major aspects - relevance and quality - together with a ranking algorithm, search engines can automatically retrieve articles that are relevant to clinical questions and are based on valid evidence. The contribution of this study has two parts. First, we approach this problem by combining methodologies. After designing a suitable document query-relevance score and methodological quality score, we combined them using various fusion methods. The result was a twofold increase in the mean average precision. Second, for correct evaluation, we built a test collection using a preexisting reliable database, the Cochrane Reviews, which allowed robust and comprehensive evaluation.

Improving MEDLINE document retrieval using automatic query expansion

In this study, we performed a comprehensive evaluation of pseudorelevance feedback technique for automatic query expansion using OHSUMED test collection. The well-known term sorting methods for the selection of expansion terms were tested in our experiments. We also proposed a new term reweighting method for further performance improvements. Through the multiple sets of test, we suggested that local context analysis was probably the most effective method of selecting good expansion terms from a set of MEDLINE documents given enough feedback documents. Both term sorting and term reweighting method might need to be carefully considered to achieve maximum performance improvements.