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Biomedical subjects

Xuemei Luo

Publications and source records attributed to Xuemei Luo.

16 recordsLinked to original sources
PubMed2006

PIPE: a protein-protein interaction prediction engine based on the re-occurring short polypeptide sequences between known interacting protein pairs.

BACKGROUND: Identification of protein interaction networks has received considerable attention in the post-genomic era. The currently available biochemical approaches used to detect protein-protein interactions are all time and labour intensive. Consequently there is a growing need for the development of computational tools that are capable of effectively identifying such interactions. RESULTS: Here we explain the development and implementation of a novel Protein-Protein Interaction Prediction Engine termed PIPE. This tool is capable of predicting protein-protein interactions for any target pair of the yeast Saccharomyces cerevisiae proteins from their primary structure and without the need for any additional information or predictions about the proteins. PIPE showed a sensitivity of 61% for detecting any yeast protein interaction with 89% specificity and an overall accuracy of 75%. This rate of success is comparable to those associated with the most commonly used biochemical techniques. Using PIPE, we identified a novel interaction between YGL227W (vid30) and YMR135C (gid8) yeast proteins. This lead us to the identification of a novel yeast complex that here we term vid30 complex (vid30c). The observed interaction was confirmed by tandem affinity purification (TAP tag), verifying the ability of PIPE to predict novel protein-protein interactions. We then used PIPE analysis to investigate the internal architecture of vid30c. It appeared from PIPE analysis that vid30c may consist of a core and a secondary component. Generation of yeast gene deletion strains combined with TAP tagging analysis indicated that the deletion of a member of the core component interfered with the formation of vid30c, however, deletion of a member of the secondary component had little effect (if any) on the formation of vid30c. Also, PIPE can be used to analyse yeast proteins for which TAP tagging fails, thereby allowing us to predict protein interactions that are not included in genome-wide yeast TAP tagging projects. CONCLUSION: PIPE analysis can predict yeast protein-protein interactions. Also, PIPE analysis can be used to study the internal architecture of yeast protein complexes. The data also suggests that a finite set of short polypeptide signals seem to be responsible for the majority of the yeast protein-protein interactions.

Algorithms↗
PubMed2006

Evaluation of a Web-based education program on reducing medication dosing error: a multicenter, randomized controlled trial.

CONTEXT: The Broselow Pediatric Resuscitation Tape has been shown to be effective in reducing medication dosing error among pediatric emergency providers. However, the tape has often been used inappropriately or incorrectly. OBJECTIVE: To evaluate whether a Web-based education program on proper use of the tape could reduce medication dosing errors and time to determine dose. DESIGN, SETTING, AND PARTICIPANTS: A randomized, controlled trial conducted among 89 pediatric emergency providers from 3 study sites. INTERVENTION: All study subjects participated in a videotaped simulated stabilization scenario and were then randomly assigned to control or education group. After the intervention, all subjects participated in another simulation. MAIN OUTCOMES MEASURES: The primary outcomes included dosing deviation from accepted dose range for each medication prescribed and dosing deviation summary, calculated by averaging dosing deviation for all medications. The secondary outcomes included time to determine a dose for each medication prescribed, and dosing time summary; that is, the average time to determine doses for all medications prescribed. RESULTS: No significant difference was observed in the demographic characteristics of the 2 groups. After the educational intervention, the average (12.6% vs. 24.9%) and median (7.1% vs. 20.1%) dosing deviation summary were much lower in the education group than in the control group. The difference in the median dosing deviation summary between the 2 groups was statistically significant (P = 0.0002). Similar results were observed for the dosing time. The education group demonstrated a lower average (16 vs. 20 seconds) and lower median (15 vs. 18 seconds) dosing time summary than the control group. The difference in the median dosing time summary between the 2 groups was statistically significant (P = 0.02). Analysis of each medication prescribed indicated that the decrease in the dosing deviation and dosing time in the education group was most obvious for several specific medications. CONCLUSIONS: The Web-based education program on the proper use of the Broselow Pediatric Resuscitation Tape could improve dosing accuracy and reduce dosing time.

Child↗
PubMed2006

Simulation of pediatric trauma stabilization in 35 North Carolina emergency departments: identification of targets for performance improvement.

OBJECTIVE: Trauma is the leading cause of death in children. Most children present to community hospital emergency departments (EDs) for initial stabilization. Thus, all EDs must be prepared to care for injured children. The objectives of this study were to (1) characterize the quality of trauma stabilization efforts in EDs and (2) identify targets for educational interventions. METHODS: This was a prospective observational study of simulated trauma stabilizations, that is, "mock codes," at 35 North Carolina EDs. An evaluation tool was created to score each mock code on 44 stabilization tasks. Primary outcomes were (1) interrater reliability of tool, (2) overall performance by each ED, and (3) performance per stabilization task. RESULTS: Evaluation-tool interrater reliability was excellent. The median number of stabilization tasks that needed improvement by the EDs was 25 (57%) of 44 tasks. Although problems were numerous and varied, many EDs need improvement in tasks uniquely important and/or complicated in pediatric resuscitations, including (1) estimating a child's weight (17 of 35 EDs [49%]), (2) preparing for intraosseous needle placement (24 of 35 [69%]), (3) ordering intravenous fluid boluses (31 of 35 [89%]), (4) applying warming measures (34 of 35 [97%]), and (5) ordering dextrose for hypoglycemia (34 of 35 [97%]). CONCLUSIONS: This study used simulation to identify deficiencies in stabilization of children presenting to EDs, revealing that mistakes are ubiquitous. ED personnel were universally receptive to feedback. Future research should investigate whether interventions aimed at improving identified deficiencies can improve trauma stabilization performance and, ultimately, the outcomes of children who present to EDs.

Child, Preschool↗
PubMed2005

Following in vitro activation of mitogen-activated protein kinases by mass spectrometry and tryptic peptide analysis: purifying fully activated p38 mitogen-activated protein kinase alpha.

p38 mitogen-activated protein kinase alpha (MAPKalpha) belongs to the MAPK subfamily, which plays a pivotal role in cell signal transduction, where it mediates responses to cell stresses and, to a lesser extent, growth factors. Although its cellular function has been under intense scrutiny since its initial discovery, little progress has been made in understanding its kinetic mechanism. A contributory factor has been the lack of a fast and rigorous method for the purification of activated p38 MAPKalpha in sufficient quantity and purity for biophysical studies. Here we present a method for the preparation of milligram quantities of activated p38 MAPKalpha, specifically phosphorylated on Thr180 and Tyr182. Purification of the inactive (unphosphorylated) p38 MAPKalpha is facilitated by an N-terminal hexahistidine tag. Removal of this tag from His6-p38 MAPKalpha, prior to its activation, is essential to ensure preparation of high yields of homogeneous, dually phosphorylated enzyme. Activation is achieved on incubation with a glutathione S-transferase (GST) fusion of the constitutively active mutant of the upstream activator, MKK6b (GST-MKK6b S207E T211E), in the presence of MgATP2-. Notably, we show that specific formation of activated p38 MAPKalpha can be quantified by following the formation of the bis-phosphorylated tryptic peptide, 173-HTDDEMT*GY*VATR-186, using [gamma-32P]adenosine triphosphate (ATP) as the phosphate source and reverse-phase high-performance liquid chromatography (HPLC) to separate the phosphopeptides. This approach offers the only means to specifically determine both stoichiometry and specificity of p38 MAPKalpha phosphorylation.

Amino Acid Sequence↗
PubMed2005

[Study on the association among total immunoglobulin E and eosinophil in nasal polyp].

OBJECTIVE: To explore the expression of total immunoglobulin E(IgE) and eosinophil in nasal polyp and their roles in the pathogenesis of nasal polyp. METHOD: Thirty eight patients with nasal polyp and 15 control cases were chosen. All samples were stained with Chromotrope 2R histochemical and SP immunohistochemical method separately to examine eosinophil and total IgE+ cells in nasal polyp. RESULT: (1) The level of total IgE and eosinophil in nasal polyp was all significantly higher than that in normal control specimens (P < 0.01). (2) The positive correlation of total IgE and eosinophil was significant (r = 0.843, P < 0.01). CONCLUSION: Nasal polyp is a disease characterized by eosinophils infiltration. Type I allergic reaction mediated by IgE assemble and activate eosinophils which may play an important role in the infiltration pathogenesis of nasal polyp.

Adolescent↗
PubMed2004

Prescription of nonsteroidal anti-inflammatory drugs and muscle relaxants for back pain in the United States.

STUDY DESIGN: Secondary analysis of the 2000 Medical Expenditure Panel Survey (MEPS). OBJECTIVE.: To examine national prescription patterns of nonsteroidal anti-inflammatory drugs (NSAIDs) and muscle relaxants among individuals with back pain in the United States. SUMMARY OF BACKGROUND DATA: There is a lack of information on national prescription patterns of NSAIDs and muscle relaxants among individuals with back pain in the United States. METHODS: Traditional NSAIDs, cyclooxygenase-2-specific (COX-2) inhibitors, and muscle relaxants were investigated. Individuals with back pain were stratified by socio-demographic characteristics and geographic regions. For each medication category, overall prescribing frequency was compared across different strata and individual drug prescription was analyzed. RESULTS: Traditional NSAIDs, COX-2 inhibitors, and muscle relaxants, respectively, accounted for 16.3%, 10%, and 18.5% of total prescriptions for back pain in 2000. Among individual drugs, ibuprofen and naproxen accounted for most of the prescriptions for traditional NSAIDs (60%), whereas two thirds of the prescriptions for muscle relaxants were attributable to cyclobenzaprine, carisoprodol, and methocarbamol. Prescription of COX-2 inhibitors or muscle relaxants demonstrated wide variations across different regions. Several individual characteristics including age, race, and educational level were associated with the prescription of some of the medications. CONCLUSIONS: Neither traditional NSAIDs, nor COX-2 inhibitors, nor muscle relaxants dominated prescriptions for back pain. However, a small number of individual drugs were attributable to most of the prescriptions for traditional NSAIDs or muscle relaxants. The prescription of some of the medications demonstrated wide variations across different regions or different racial and educational groups. More studies are needed to understand the source of the variations and what constitutes optimal prescribing.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2004

Patterns and trends in opioid use among individuals with back pain in the United States.

STUDY DESIGN: Secondary analysis of Medical Expenditure Panel Survey from 1996 to 1999. OBJECTIVE: To examine patterns in opioid use in 1996, 1997, 1998, and 1999 among individuals with back pain in the United States and to investigate trends in the use of overall and individual opioid category. SUMMARY OF BACKGROUND DATA: To the authors' best knowledge, no study has examined at a national level the patterns and trends in opioid use among individuals with back pain in the United States. METHODS: Individuals with back pain were stratified by sociodemographic characteristics and geographic regions. Rates of overall opioid use were compared among different strata by the use of simple and multivariate logistic regression models. To investigate trends in opioid use, use rates of the overall and individual opioid category in each year were calculated and compared. RESULTS: From 1996 to 1999, wide variations in overall opioid use were consistently observed among individuals with different educational levels, family income, and health insurance status. Regional variation in opioid use was also observed for most of the 4 years. After adjustment for covariates, health insurance status and geographic regions were consistent predictors of opioid use from 1997 to 1999. Trend analysis indicated that the rates of overall opioid use increased slightly across the 4-year span. Among individual opioid categories, the use of oxycodone or hydrocodone increased, whereas the use of propoxyphene decreased. CONCLUSIONS: The variation in overall opioid use among individuals with back pain with different sociodemographic characteristics and from different geographic regions suggested an opportunity to improve opioid prescribing patterns. The increase in the use of hydrocodone and oxycodone indicated a need to better assess the efficacy and safety associated with these drugs among individuals with back pain.

Adolescent↗
PubMed2004

Estimates and patterns of direct health care expenditures among individuals with back pain in the United States.

STUDY DESIGN: Secondary analysis of the 1998 Medical Expenditure Panel Survey. OBJECTIVE: To estimate total health care expenditures incurred by individuals with back pain in the United States, calculate the incremental expenditures attributable to back pain among these individuals, and describe health care expenditure patterns of individuals with back pain. SUMMARY OF BACKGROUND DATA: There is a lack of updated information on health care expenditures and expenditure patterns for individuals with back pain in the United States. METHODS: This study used data from the 1998 Medical Expenditure Panel Survey, a national survey on health care utilization and expenditures. Total health care expenditures and per-capita expenditures among individuals with back pain were calculated. Multivariate regression models were used to estimate the incremental expenditures attributable to back pain. The expenditure patterns were examined by stratifying individuals with back pain by sociodemographic characteristics and medical diagnosis, and calculating per-capita expenditures for each stratum. RESULTS: In 1998, total health care expenditures incurred by individuals with back pain in the United States reached 90.7 billion dollars and total incremental expenditures attributable to back pain among these persons were approximately 26.3 billion dollars. On average, individuals with back pain incurred health care expenditures about 60% higher than individuals without back pain (3,498 dollars vs. 2,178 dollars). Among back pain individuals, at least 75% of service expenditures were attributed to those with top 25% expenditure, and per-capita expenditures were generally higher for those who were older, female, white, medically insured, or suffered from disc disorders. CONCLUSIONS: Health care expenditures for back pain in the United States in 1998 were substantial. The expenditures demonstrated wide variations among individuals with different clinical, demographic, and socioeconomic characteristics.

Adolescent↗
PubMed2004

Evaluation of a method to reduce over-the-counter medication dosing error.

OBJECTIVES: To introduce a simple method of dosing over-the-counter medication in a home setting using a color-coding concept and to compare dosing deviation from recommended dosage using the color-coded method with dosing deviation using conventional package labeling. DESIGN: Randomized controlled clinical trial. SETTING: Pediatric emergency center at a tertiary care medical center. PARTICIPANTS: A sample of 101 caregivers of children with nonemergent complaints separated into 2 groups. One group used a conventional dosing method and the other group used a color-coded method to determine and measure a dose of acetaminophen for their child. MAIN OUTCOME MEASURES: For both dose determination and dose measuring, percentage of deviation from recommended acetaminophen dosage was calculated and compared between the 2 groups. RESULTS: There was no significant difference in sociodemographic characteristics between the 2 groups. How-ever, for dose determination, the average deviation (25.8% vs 1.7%) and median deviation (1% vs 0%) from recommended dosage were both higher for the group using conventional methods compared with the group using the color-coded method. The Wilcoxon rank sum test indicated that the median deviation was significantly different between the 2 groups (P<.001). Similar results were obtained for dose measuring. The average deviation (29% vs 0.5%) and the median deviation (17.2% vs 0%) from recommended dosage were higher for the group using conventional methods compared with the group using the color-coded method. The median deviation was also significantly different between the 2 groups (P<.001). CONCLUSION: This study suggests a marked improvement in caregivers' ability to correctly determine and measure an over-the-counter medication for their child using a color-coded method compared with conventional methods.

Acetaminophen↗
PubMed2004

Cost comparisons of olanzapine and risperidone in treating schizophrenia.

OBJECTIVE: To review the literature on the healthcare costs associated with olanzapine and risperidone in treating schizophrenia. DATA SOURCES: Published English-language pharmacoeconomic studies on olanzapine and risperidone obtained through a MEDLINE search (1990-May 2003) were selected. Additional studies were identified from a manual search of the references of retrieved articles. data extraction: Based on the identified studies, data were extracted on various treatment costs associated with the use of antipsychotic drugs, concomitant drugs from other classes, inpatient care, outpatient care, and emergency care. Emphasis was placed on studies directly comparing olanzapine and risperidone. DATA SYNTHESIS: Both olanzapine and risperidone were generally associated with a trend of decrease in total medical costs compared with typical antipsychotics. When directly comparing the drugs, some studies found significant cost savings in favor of olanzapine and some suggested risperidone to save total costs. Still others showed no significant difference in total costs between the 2 drug regimens. CONCLUSIONS: While both olanzapine and risperidone appear to be more cost saving than typical antipsychotics, the literature offers no conclusive evidence to determine the comparative advantage of one versus another in terms of total cost outcomes. Major factors that contribute to the inconclusive findings may include across-study variations in populations, design, outcome measures, dosage, severity of illness, inclusion criteria, and statistical methodologies.

Benzodiazepines↗
PubMed2003

Reliability, validity, and responsiveness of the short form 12-item survey (SF-12) in patients with back pain.

STUDY DESIGN: Secondary analysis of data collected from spine patients' normal clinic visits from 1998 to 2001. OBJECTIVE: To evaluate the reliability, validity, and responsiveness of the short form 12-item survey in patients with back pain. SUMMARY OF BACKGROUND DATA: The reliability, validity, and responsiveness of the short form 12-item survey in patients with back pain has not been previously evaluated. METHODS: Patients were asked to complete a comprehensive computerized survey questionnaire during their regular clinic visits. A total of 2520 patients who indicated in their first surveys that they had back pain were included in the study of the reliability and validity of the short form 12-item survey. Of these, 506 patients completed another survey within 3-6 months of follow-up and were included in the responsiveness evaluation. RESULTS: The two summary scales of the short form 12-item survey, physical component summary and mental component summary, demonstrated internal consistency reliability, with Cronbach alpha for both scales exceeding the recommended level of 0.70. Correlation of physical component summary and mental component summary with six other measures theoretically related or unrelated to these scales performed as expected without exception, demonstrating the construct validity of the short form 12-item survey. The responsiveness of the short form 12-item survey was supported by several pieces of evidence. First, the changes in physical component summary and mental component summary scores were correlated with the changes in back pain intensity. Second, for patients whose back pain improved, there was a significant increase in the follow-up physical component summary and mental component summary scores as compared to the baseline. Third, small to moderate effect size was observed for patients whose back pain became improved or became worse. CONCLUSIONS: The short form 12-item survey demonstrated good internal consistency reliability, construct validity, and responsiveness in patients with back pain.

Academic Medical Centers↗
PubMed2003

Effect of an intervention standardization system on pediatric dosing and equipment size determination: a crossover trial involving simulated resuscitation events.

BACKGROUND: Pediatric medication dosing has been recognized as a high-error activity with the potential to cause serious harm. Few studies assess systems approaches to error reduction in pediatrics. OBJECTIVE: To estimate the decrease in deviation from recommended medication doses associated with use of a pediatric intervention standardization system in the acute setting. DESIGN: Two-period, 2-treatment crossover trial with data collected between December 1, 1999, and February 29, 2000. SETTING: Tertiary, academic medical center. PARTICIPANTS: Convenience sample of 28 resident physicians, representing 69% of pediatrics and 50% of medicine-pediatrics residents. INTERVENTION: Each resident participated in 4 simulated pediatric resuscitations. The Broselow Pediatric Emergency Tape and color-coded materials were available in either the first or second 2 scenarios. Traditional dosing references were available in all scenarios. MAIN OUTCOME MEASURE: Median difference between deviation from recommended dose range (DRDR) in scenarios where color coding was used (intervention) and DRDR in scenarios where color coding was not available (control). RESULTS: Median DRDR in intervention scenarios was 25.4% lower than in control scenarios (95% confidence interval [CI], 19.1%-32.5%; P<.001). In 4 medication prescriptions in intervention scenarios and in 54 prescriptions in control scenarios, DRDRs exceeded 100%. Median deviation from recommended equipment sizes in intervention scenarios was 0.12 size lower than in control scenarios (95% CI, 0.03-0.22 size; P<.001). Deviations in equipment size of 2 or more sizes were noted in 1 size determination in intervention scenarios and in 21 size determinations in control scenarios. CONCLUSIONS: Color coding was associated with a significant reduction in deviation from recommended doses in simulated pediatric emergencies. Numerous potentially clinically significant deviations from recommended doses and equipment sizes were avoided. Future studies should measure impact in the real clinical setting.

Academic Medical Centers↗
PubMed2003

Mass spectrometry of polyaromatic sulfur compounds in the presence of palladium(II).

Electrospray ionization mass spectrometry (ESI-MS) and tandem MS in an ion trap were used to explore the reduction of a PdCl(2) solution and the role of the metal in the formation of organosulfur radical cations. For tandem MS experiments, a 32 Da neutral loss (M - S), was observed for dibenzothiophene, thianthrene and benzonaphthothiophene, whereas both 32 and 33 Da neutral losses were observed for 2-methyldibenzothiophene and 4,6-dimethyldibenzothiophene. The effects of several variables on the formation of molecular ions or molecular fragments were studied to optimize radical cation formation, including the concentration ratio between PdCl(2) and sulfur and the collision energy. Electrochemical and chromatographic data were used to provide an explanation for the relative sensitivity observed for a mixture of polyaromatic sulfur heterocycles.

Cations↗
PubMed2003

Children's health insurance status and emergency department utilization in the United States.

OBJECTIVES: Emergency department (ED) overcrowding has become a national problem. Children account for nearly 25% of overall ED visits. It has been reported that uninsured and publicly insured children are likely to visit the ED for urgent and nonurgent problems, yet it remains unclear to what extent health insurance status would influence children's overall ED utilization or ED utilization for nonurgent problems at the national level after controlling for other confounding factors. The objective of this study was to examine the effect of health insurance status on children's overall ED utilization and children's ED utilization for nonurgent problems among the general pediatric population in the United States. METHODS: Secondary analysis of the household component of the 1997 Medical Expenditure Panel Survey on 10 193 children younger than 18 years. The main outcome measures were annual overall ED utilization and ED utilization for nonurgent problems. RESULTS: During 1997, 10.8% of children were uninsured for the entire year. A total of 17.5% of children were publicly insured the entire year, whereas 55.3% of children held private insurance the entire year. There were also 16.5% of children who were insured only part of the year. Without adjusting for covariates, publicly insured children were more likely to have an ED visit during the year than both privately insured children (unadjusted odds ratio [OR]: 1.26; 95% confidence interval [CI]: 1.03-1.55) and uninsured children (unadjusted OR: 1.46; 95% CI: 1.1-1.95). The difference between publicly insured and privately insured children (adjusted OR: 0.90; 95% CI: 0.70-1.16) and between publicly insured and uninsured children (adjusted OR: 1.12; 95% CI: 0.84-1.49) became insignificant after controlling for covariates. With or without adjustments for covariates, there was no significant difference in the likelihood of having an ED visit between privately insured and uninsured children. Similar to the utilization pattern of overall ED visits, publicly insured children were more likely to have a nonurgent ED visit than both privately insured (unadjusted OR: 1.86; 95% CI: 1.36-2.53) and uninsured children (unadjusted OR: 1.81; 95% CI: 1.15-2.84). Both differences disappeared after controlling for covariates. There was no significant difference in the likelihood of nonurgent ED visits between privately insured and uninsured children with or without adjustments for covariates. CONCLUSIONS: Health insurance status was not associated with children's overall ED use or children's ED use for nonurgent problems at the national level. Our findings suggest that policy efforts in an attempt to relieve ED overcrowding conditions should look for measures beyond solely making changes in health insurance coverage for children.

Adolescent↗
PubMedDate not supplied

Relationships of clinical, psychologic, and individual factors with the functional status of neck pain patients.

OBJECTIVE: The objective of this study was to use both generic and disease-specific functional measures examining relationships of clinical, psychologic, and individual factors with the functional status of neck pain patients. METHODS: Patients who visited a university-based spine clinic and reported neck pain were included in this study. A comprehensive computerized survey questionnaire was used to collect the information related to this study. The questionnaire also contained a generic measure, short form 12-item survey (SF-12), and a disease-specific measure, neck disability index (NDI). Correlation and multiple regression analysis were conducted to examine the relationships. RESULTS: A range of clinical, psychologic, and individual factors emerged to be significant predictors of the NDI or physical component of the SF-12 (PCS). The predictors of higher NDI included higher levels of neck pain, higher levels of back pain, higher levels of pain in arm or shoulder areas, not working, lower education, higher stress, the presence of depression or anxiety, and smoking. The predictors of lower PCS included not working, higher levels of back pain, higher levels of neck pain, lower education, female sex, the presence of cardiovascular disorders, the absence of cervical disk disorders, and older age. CONCLUSIONS: The predictors of the NDI or PCS appear to be multidimensional. Interventions designed to maximally improve the functional status of neck pain patients should be multifaceted and involve multidisciplinary teams. Selection of the most appropriate functional measures for an intervention study should consider differences between the generic and disease-specific measures in terms of their respective relationships with targeted factors. Prospective studies are needed to confirm the relationships observed in this study.

Activities of Daily Living↗