Production of Highly Polarized Positrons Using Polarized Electrons at MeV Energies.

The Polarized Electrons for Polarized Positrons experiment at the injector of the Continuous Electron Beam Accelerator Facility has demonstrated for the first time the efficient transfer of polarization from electrons to positrons produced by the polarized bremsstrahlung radiation induced by a polarized electron beam in a high-Z target. Positron polarization up to 82% have been measured for an initial electron beam momentum of 8.19 MeV/c, limited only by the electron beam polarization. This technique extends polarized positron capabilities from GeV to MeV electron beams, and opens access to polarized positron beam physics to a wide community.

A transition in brain state during propofol-induced unconsciousness.

Rhythmic oscillations shape cortical dynamics during active behavior, sleep, and general anesthesia. Cross-frequency phase-amplitude coupling is a prominent feature of cortical oscillations, but its role in organizing conscious and unconscious brain states is poorly understood. Using high-density EEG and intracranial electrocorticography during gradual induction of propofol general anesthesia in humans, we discovered a rapid drug-induced transition between distinct states with opposite phase-amplitude coupling and different cortical source distributions. One state occurs during unconsciousness and may be similar to sleep slow oscillations. A second state occurs at the loss or recovery of consciousness and resembles an enhanced slow cortical potential. These results provide objective electrophysiological landmarks of distinct unconscious brain states, and could be used to help improve EEG-based monitoring for general anesthesia.

Cognitive performance profiles by latent classes of drug use.

BACKGROUND AND OBJECTIVES: The relationship between substance use and cognitive deficits is complex and requires innovative methods to enhance understanding. The present study is the first to use LCA to examine associations of drug use patterns with cognitive performance. METHODS: Cocaine/heroin users (N = 552) completed questionnaires, and cognitive measures. LCA identified classes based on past-month drug use and adjusted for probabilities of group membership when examining cognitive performance. Latent indicators were: alcohol (ALC), cigarettes (CIG), marijuana (MJ), crack smoking (CS), nasal heroin (NH), injection cocaine (IC), injection heroin (IH), and injection speedball (IS). Age and education were included as covariates in model creation. RESULTS: Bootstrap likelihood ratio test (BLRT) supported a 5-class model. Prevalent indicators (estimated probability of over 50%) for each class are as follows: "Older Nasal Heroin/Crack Smokers" (ONH/CS, n = 166.9): ALC, CIG, NH, CS; "Older, Less Educated Polysubstance" (OLEP, n = 54.8): ALC, CIG, CS, IH, IC, and IS; "Younger Multi-Injectors" (MI, n = 128.7): ALC, CIG, MJ, IH, IC, and IS; "Less Educated Heroin Injectors" (LEHI, n = 87.4): CIG, IH; and "More Educated Nasal Heroin" users (MENH, n = ALC, CIG, NH. In general, all classes performed worse than established norms and older, less educated classes performed worse, with the exception that MENH demonstrated worse cognitive flexibility than YMI. DISCUSSION AND CONCLUSIONS: This study demonstrated novel applications of a methodology for examining complicated relationships between polysubstance use and cognitive performance. SCIENTIFIC SIGNIFICANCE: Education and/or nasal heroin use are associated with reduced cognitive flexibility in this sample of inner city drug users.

Disparities across Diverse Populations in the Health and Treatment of Patients with Osteoarthritis.

The study of disparities across diverse populations regarding the health and treatment of patients with osteoarthritis (OA) is recognized as a priority for investigation and action by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) and the American Academy of Orthopedic Surgeons (AAOS). OA is a common condition that increases with age, but with prevalence generally similar across racial and ethnic groups. However, disparities in the treatment of OA among racial, ethnic, and socioeconomic groups are well-documented and continue to rise and persist. The reasons are complex, likely involving a combination of patient, provider, and healthcare system factors. Treatment disparities among these different populations have an impact on clinical outcomes, healthcare, and productivity, and are projected to increase significantly with the growing diversity of the United States population. The aim of this short review is to summarize studies of racial, ethnic, and socioeconomic disparities among patients with OA in the United States, with a focus on prevalence, treatment utilization, and clinical and economic outcomes.

Rethink Vape: Development and evaluation of a risk communication campaign to prevent youth E-cigarette use.

INTRODUCTION: E-cigarettes are now the most common form of tobacco use among adolescents, and use is associated with increased risk of initiation of cigarette smoking. This project used a community-engaged research process to develop and pilot a risk communication campaign to prevent youth vaping. METHOD: The research team worked with a 36-member Teen Advisory Council and a 19-member Expert Panel. Together, the team employed survey (N = 674) and focus group (N = 82) methodologies, and hired a marketing company to partner on development of the campaign. Campaign concepts were developed, eliminated, and/or modified through an iterative process of feedback and refinement. The final campaign included video ads (https://bit.ly/2QMR8gH) a microsite (rethinkvape.org), and social media sites (@rethinkvape). The campaign communicated three messages to teens: what's in the vapor, health risks, and connections to big tobacco. Prior to launch of the campaign, a randomized controlled 2 (time) × 2 (group) online experiment was conducted to evaluate the campaign (N = 268). RESULTS: Repeated measures mixed analyses of variance indicated that vaping knowledge, perceptions of risk, and anti-vape intentions significantly increased among teens viewing the Rethink Vape Materials compared to their own baseline, while control participants did not change. Following evaluation, the team launched a 6-week online media campaign with a teen-targeted geo-fence radius to deliver 3,838,465 impressions, 770,443 completed video views, and 18,316 clicks in mobile app, Snapchat, YouTube, and Spotify platforms. The majority of placements exceeded industry standards, with mobile pre-roll and Snapchat as top performers. CONCLUSIONS: The e-cigarette campaign showed promising signs of effectiveness and scalability.

Broadband slow-wave modulation in posterior and anterior cortex tracks distinct states of propofol-induced unconsciousness.

A controversy has developed in recent years over the roles of frontal and posterior cortices in mediating consciousness and unconsciousness. Disruption of posterior cortex during sleep appears to suppress the contents of dreaming, yet activation of frontal cortex appears necessary for perception and can reverse unconsciousness under anesthesia. We used anesthesia to study how regional cortical disruption, mediated by slow wave modulation of broadband activity, changes during unconsciousness in humans. We found that broadband slow-wave modulation enveloped posterior cortex when subjects initially became unconscious, but later encompassed both frontal and posterior cortex when subjects were more deeply anesthetized and likely unarousable. Our results suggest that unconsciousness under anesthesia comprises several distinct shifts in brain state that disrupt the contents of consciousness distinct from arousal and awareness of those contents.

Mutations of the BCR-ABL-kinase domain occur in a minority of patients with stable complete cytogenetic response to imatinib.

Residual leukemia is demonstrable by reverse transcriptase-polymerase chain reaction in most patients with chronic myeloid leukemia who obtain a complete cytogenetic response (CCR) to imatinib. In patients who relapse during imatinib therapy, a high rate of mutations in the kinase domain of BCR-ABL have been identified, but the mechanisms underlying disease persistence in patients with a CCR are poorly characterized. To test whether kinase domain mutations are a common mechanism of disease persistence, we studied patients in stable CCR. Mutations were demonstrated in eight of 42 (19%) patients with successful amplification and sequencing of BCR-ABL. Mutation types were those commonly associated with acquired drug resistance. Four patients with mutations had a concomitant rise of BCR-ABL transcript levels, two of whom subsequently relapsed; the remaining four did not have an increase in transcript levels and follow-up samples, when amplifiable, were wild type. BCR-ABL-kinase domain mutations in patients with a stable CCR are infrequent, and their detection does not consistently predict relapse. Alternative mechanisms must be responsible for disease persistence in the majority of patients.

Defining the surgical personality: a preliminary study.

Noting that noncognitive factors may be more predictive of success in a medical career than is intellectual ability or cognitive performance, we undertook a study to determine whether a surgical personality exists and to delineate the temperament and personality traits that contribute to its definition. The Krug Adult Personality Inventory, the Strelau Temperament Inventory, and Barclay's adjective checklist were administered to 110 physicians, 35 in a "controllable lifestyle" specialty, 28 in primary care, and 47 in surgery or a surgery subspecialty. In addition, participants completed a stress inventory. Results showed that surgeons form a distinct and homogeneous group based on temperament and personality traits. We suggest that noncognitive factors can be of use to medical educators in the selection, counseling, training, and evaluation of medical personnel.

Medical students' confidence and the characteristics of their clinical experiences in a primary care clerkship.

PURPOSE: To investigate the relationship between medical students' confidence and their experiences in caring for patients within a primary care clerkship, because hands-on experience is assumed to be positively related to the development of confidence (a subjective marker of competence). METHOD: The participants were 60 students from the class of 1992 who completed a required third-year ambulatory care clerkship at the University of Kentucky Medical Center. The students documented their one-on-one experiences in patient care (under the supervision of preceptors in family practice, general pediatrics, or general internal medicine) by completing data cards on each patient encounter. Also, for each encounter, the students used a Likert scale to rate their levels of confidence in dealing with the patient's primary diagnosis. The variables recorded on the cards were then used to predict the students' levels of confidence during the encounters. The statistical analysis included descriptive statistics, Pearson correlations, and a stepwise multiple-regression procedure. RESULTS: The mean number of patient encounters per student was 99. The regression procedure selected three variables from the data cards as significant independent predictors of the students' confidence: management responsibility for the patient's problem (R2 = .40), prior exposure to the patient's problem (R2 = .08), and performance of laboratory work during the patient encounter (R2 = .06). These variables were responsible for predicting 54% of the observed variance in the students' confidence (R2 = .54). CONCLUSION: Hands-on clinical experience was more important for building students' confidence than any other encounter variable.

Demographic, educational, and psychosocial factors influencing the choices of primary care and academic medical careers.

PURPOSE: To identify demographic, psychosocial, and educational variables that differentiate physicians who have chosen careers in primary care from those who have chosen academic medicine. METHOD: Questionnaires were distributed in the spring of 1992 to 704 physicians (546 in primary care practices and 143 in academic medicine) who had graduated from the University of Kentucky College of Medicine, 1964-1991. Mann-Whitney U tests and analyses of variance were used for statistical comparisons. RESULTS: A total of 336 physicians responded: 246 in primary care and 90 in academic medicine. The primary care physicians tended to come from smaller cities than did the academic physicians (p < .0001). The primary care physicians also had made their career choices earlier than did the academic physicians (p < .0001). For the academic physicians, long-term participation in research, intellectual stimulation, content of specialty, and influence of a mentor or role model were significantly more important factors than they were for the primary care physicians, for whom length of training, direct patient contact, and threats of malpractice suits were significantly more important. CONCLUSION: The results corroborate the findings of previous studies that suggest that career-choice factors are influenced by admission procedures and curricular structures. The number of graduates choosing careers in either primary care or academic medicine may be increased by increasing their experiences in those fields. Medical schools may be able to use demographic, psychosocial, and curricular factors to fulfill their particular primary mandates, whether they be producing physicians in primary care or in academic medicine.

Malnutrition in rheumatoid arthritis.

A nutrition study was conducted in thirty-eight hospitalized rheumatoid arthritis (RA) patients. Twenty-seven (71.1%) had a high likelihood of malnutrition (LOM). Laboratory and anthropometric data suggest that multiple vitamin, calory, and protein deficiencies are present. Age, female sex and a poor grip strength correlated with some indices of malnutrition. Fifteen of 18 patients with a high LOM had a bad outcome whereas 3 of 7 patients with a low LOM had a bad outcome. Malnutrition per se may be a contributing factor to increased morbidity and mortality in RA.

Mother-child development elective: a formal educational maternity leave.

Policies for maternity and parenting leave in physician training programs are often lacking or inadequate. A structured elective in mother-child development has been developed by the University of Kentucky Department of Family Practice Residency Program in an attempt to provide a practical alternative for the resident-in-training who is a new parent. The course provides for the integration of personal and professional activities into an educationally beneficial experience. The new course meets the requirements of both the American Board of Family Practice and the Residency Review Committee. The first participants in the elective course have been extremely positive about its merit.

Physician extenders: who is using them?

BACKGROUND: Nurse practitioners and physician assistants (physician extenders) are playing an increased role in medical care. The purpose of this research was to determine the proportion of adults who have received health care from physician extenders. METHODS: This study used the subject population of the 1990 Kentucky Health Survey, a probability survey of all households in Kentucky. Study personnel contacted subjects using random digit telephone dialing. Subjects were then interviewed to ascertain whether subjects had received health care from physician extenders and whether they were satisfied with that care. RESULTS: Of 687 participating subjects, 25% had received care from physician extenders during the previous two years, primarily for minor problems and routine checkups. More than 90% of these subjects reported satisfaction with the care they received. Users of physician extenders did not differ from nonusers with respect to income, education, insurance status, self-assessment of health status, or rural versus urban location. Men used physician extenders more frequently than women. CONCLUSIONS: A substantial proportion of the population has used physician extenders. Patient satisfaction with physician extenders is high. Use of physician extenders may be an effective strategy for improving delivery of primary care.

Total elbow replacement.

Elbow joint replacement is performed primarily in patients with severe elbow pain and elbow joint destruction caused by rheumatoid arthritis. The capitellocondylar implant is the prototype of the nonconstrained elbow resurfacing implant. Successful total elbow joint replacement can result in pain relief and improve rotation and flexion of the arm. Outpatient and inpatient nursing intervention in coordination with occupational therapy promotes optimum function.

Statistical modeling of behavioral dynamics during propofol-induced loss of consciousness.

BACKGROUND: Accurate quantitative analysis of the changes in responses to external stimuli is crucial for characterizing the timing of loss and recovery of consciousness induced by anesthetic drugs. We studied induction and emergence from unconsciousness achieved by administering a computer-controlled infusion of propofol to ten human volunteers. We evaluated loss and recovery of consciousness by having subjects execute every 4s two interleaved computer delivered behavioral tasks: responding to verbal stimuli (neutral words or the subject's name), or less salient stimuli of auditory clicks. NEW METHOD: We analyzed the data using state-space methods. For each stimulus type the observation model is a two-stage binomial model and the state model is two dimensional random walk in which one cognitive state governs the probability of responding and the second governs the probability of correctly responding given a response. We fit the model to the experimental data using Bayesian Monte Carlo methods. RESULTS: During induction subjects lost responsiveness to less salient clicks before losing responsiveness to the more salient verbal stimuli. During emergence subjects regained responsiveness to the more salient verbal stimuli before regaining responsiveness to the less salient clicks. COMPARISON WITH EXISTING METHOD(S): The current state-space model is an extension of previous model used to analyze learning and behavioral performance. In this study, the probability of responding on each trial is obtained separately from the probability of behavioral performance. CONCLUSIONS: Our analysis provides a principled quantitative approach for defining loss and recovery of consciousness in experimental studies of general anesthesia.

Latent classes of heroin and cocaine users predict unique HIV/HCV risk factors.

BACKGROUND: Patterns of heroin and cocaine use vary and may be associated with unique risk factors for bloodborne infections. METHODS: Latent class analysis identified sub-populations of 552 heroin and cocaine users in Baltimore, Maryland. Using latent class regression, these classes were analyzed for associations with demographic characteristics, risky behaviors, Hepatitis C, and HIV. RESULTS: Three classes were found: Crack/Nasal-Heroin users (43.5%), Polysubstance users (34.8%), and Heroin Injectors (21.8%). Compared to Polysubstance users, Crack/Nasal-Heroin users were almost 7 times more likely to identify as Black (OR=6.97, 95% CI=4.35-11.2). Sharing needles was over 2.5 times more likely among Polysubstance users than among Heroin Injectors (OR=2.66, 95% CI=1.49-4.75). Crack/Nasal-Heroin users were 2.5 times more likely than Polysubstance users to exchange drugs for sex (OR=2.50, 95% CI=1.22-5.13). Crack/Nasal-Heroin users were less likely than Heroin Injectors to have Hepatitis C (OR=0.10, 95% CI=0.06-0.18), but no significant differences were found for HIV. CONCLUSIONS: Subpopulations of cocaine and heroin users differed in demographic classifications, HIV-risk behaviors, and Hepatitis C infection. All subpopulations included substantial numbers of HIV-positive individuals. Findings provide further evidence that non-injection drug users face significant infectious disease risk.

Cigarette smoking, illicit drug use, and routes of administration among heroin and cocaine users.

Cigarette smoking is ubiquitous among illicit drug users. Some have speculated that this may be partially due to similarities in the route of administration. However, research examining the relationship between cigarette smoking and routes of administration of illicit drugs is limited. To address this gap, we investigated sociodemographic and drug use factors associated with cigarette smoking among cocaine and heroin users in the Baltimore, Maryland community (N=576). Regular and heavy cigarette smokers were more likely to be White, have a history of a prior marriage, and have a lower education level. Regular smoking of marijuana and crack was associated with cigarette smoking, but not heavy cigarette smoking. Injection use was more common among heavy cigarette smokers. In particular, regular cigarette smokers were more likely to have a lifetime history of regularly injecting heroin. Optimal prevention and treatment outcomes can only occur through a comprehensive understanding of the interrelations between different substances of abuse.

Cigarette smoking and short-term addiction treatment outcome.

Cigarette smoking is common among patients in cocaine and opioid dependence treatment, and may influence treatment outcome. We addressed this issue in a secondary analysis of data from an outpatient clinical trial of buprenorphine treatment for concurrent cocaine and opioid dependence (13 weeks, N=200). The association between cigarette smoking (lifetime cigarette smoking status, number of cigarettes smoked per day prior to study entry) and short-term treatment outcome (% of urine samples positive for cocaine or opioids, treatment retention) was evaluated with analysis of covariance, bivariate correlations, and multivariate linear regression. Nicotine-dependent smokers (66% of participants) had a significantly higher percentage of cocaine-positive urine samples than non-smokers (12% of participants) (76% vs. 62%), but did not differ in percentage of opioid-positive urine samples or treatment retention. Number of cigarettes smoked per day at baseline was positively associated with percentage of cocaine-positive urine samples, even after controlling for baseline sociodemographic and drug use characteristics, but was not significantly associated with percentage of opioid-positive urine samples or treatment retention. These results suggest that cigarette smoking is associated with poorer short-term outcome of outpatient treatment for cocaine dependence, but perhaps not of concurrent opioid dependence, and support the importance of offering smoking cessation treatment to cocaine-dependent patients.

Robust time-varying multivariate coherence estimation: application to electroencephalogram recordings during general anesthesia.

Coherence analysis characterizes frequency-dependent covariance between signals, and is useful for multivariate oscillatory data often encountered in neuroscience. The global coherence provides a summary of coherent behavior in high-dimensional multivariate data by quantifying the concentration of variance in the first mode of an eigenvalue decomposition of the cross-spectral matrix. Practical application of this useful method is sensitive to noise, and can confound coherent activity in disparate neural populations or spatial locations that have a similar frequency structure. In this paper we describe two methodological enhancements to the global coherence procedure that increase robustness of the technique to noise, and that allow characterization of how power within specific coherent modes change through time.

Bayesian analysis of trinomial data in behavioral experiments and its application to human studies of general anesthesia.

Accurate quantification of loss of response to external stimuli is essential for understanding the mechanisms of loss of consciousness under general anesthesia. We present a new approach for quantifying three possible outcomes that are encountered in behavioral experiments during general anesthesia: correct responses, incorrect responses and no response. We use a state-space model with two state variables representing a probability of response and a conditional probability of correct response. We show applications of this approach to an example of responses to auditory stimuli at varying levels of propofol anesthesia ranging from light sedation to deep anesthesia in human subjects. The posterior probability densities of model parameters and the response probability are computed within a Bayesian framework using Markov Chain Monte Carlo methods.