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Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of postoperative infection.1 Patients who are undergoing vascular surgical procedures may be at particular risk for MRSA infection. MRSA can seed vascular graft material, and patients with vascular disease tend to be older and to have comorbidities such as diabetes and poor circulation, factors that may increase susceptibility to infection. A United Kingdom retrospective study found that from 1994 to 2000, the prevalence of patients with positive test results for MRSA in a vascular unit increased from 1% to 6%.2 In fact, studies indicate that MRSA has become the leading cause of infection among vascular surgery patients in the United States and the United Kingdom.1,3–5 Postoperative MRSA infection in vascular surgery patients can cause substantial morbidity and potential mortality.6 MRSA infection is associated with longer hospital stays, increased morbidity and mortality, and higher rates of amputation, revision amputation, and graft removal, compared with those of other infections.1,3,5,7–9 MRSA infection also correlates with lower limb-salvage rates, lower healing power, and delayed healing.3,4 Therefore, reducing the incidence of MRSA infection may be key to improving vascular surgery outcomes.10 Testing patients preoperatively for MRSA colonization and decolonizing patients with positive test results (ie, administering antibiotics or antiseptic medication to remove MRSA colonization) is a potential strategy to prevent postoperative MRSA infection. Patients with MRSA nasal colonization may be at greater risk for postoperative MRSA infection. One study found a 30.7% MRSA infection rate among vascular surgery patients with MRSA nasal colonization, compared with a 0.67% rate among vascular surgery patients without MRSA nasal colonization.11 This suggests that preoperative testing and decolonization may be important. However, studies have not established the cost-effectiveness of such a strategy. In addition, there is no consensus about what decolonization regimen should be used or how effective decolonization may be. Moreover, MRSA colonization prevalence may vary greatly from location to location. We developed a computer simulation model to determine the economic value of the testing and decolonization strategy before vascular operations. The model simulated the decision of whether to perform preoperative MRSA testing on patients who were about to undergo vascular surgical procedures and to decolonize those with positive test results. Sensitivity analyses varied key model parameters and allowed us to delineate how the cost-effectiveness of such a strategy may vary by MRSA prevalence, decolonization success rate, and decolonization cost. The results of our model may help guide policy making and the design of future epidemiological and clinical studies.

Employers may be loath to fund vaccination programs without understanding the economic consequences. We developed a decision analytic computational simulation model including dynamic transmission elements that estimated the cost-benefit of employer-sponsored workplace vaccination from the employer's perspective. Implementing such programs was relatively inexpensive (

Background: Due to the unpredictable burden of pandemic influenza, the best strategy to manage testing, such as rapid or polymerase chain reaction (PCR), and antiviral medications for patients who present with influenza-like illness (ILI) is unknown. Methodology/Principal Findings: We developed a set of computer simulation models to evaluate the potential economic value of seven strategies under seasonal and pandemic influenza conditions: (1) using clinical judgment alone to guide antiviral use, (2) using PCR to determine whether to initiate antivirals, (3) using a rapid (point-of-care) test to determine antiviral use, (4) using a combination of a point-of-care test and clinical judgment, (5) using clinical judgment and confirming the diagnosis with PCR testing, (6) treating all with antivirals, and (7) not treating anyone with antivirals. For healthy younger adults (

Background—The %carbohydrate deficient transferrin (%CDT) test offers objective evidence of unhealthy alcohol use but its cost-effectiveness in primary care conditions is unknown. Methods—Using a decision tree and Markov model, we performed a literature-based costeffectiveness analysis of 4 strategies for detecting unhealthy alcohol use in adult primary care patients: (i) Questionnaire Only, using a validated 3-item alcohol questionnaire; (ii) %CDT Only; (iii) Questionnaire followed by %CDT (Questionnaire-%CDT) if the questionnaire is negative; and (iv) No Screening. For those patients screening positive, clinicians performed more detailed assessment to characterize unhealthy use and determine therapy. We estimated costs using Medicare reimbursement and the Medical Expenditure Panel Survey. We determined sensitivity, specificity, prevalence of disease, and mortality from the medical literature. In the base case, we calculated the incremental cost-effectiveness ratio (ICER) in 2006 dollars per quality-adjusted life year ($/QALY) for a 50-year-old cohort. Results—In the base case, the ICER for the Questionnaire-%CDT strategy was $15,500/QALY compared with the Questionnaire Only strategy. Other strategies were dominated. When the prevalence of unhealthy alcohol use exceeded 15% and screening age was

We describe herein a protocol for the production of antigen-specific human monoclonal antibodies (hmAbs). Antibody-secreting cells (ASCs) are isolated from whole blood collected 7 d after vaccination and sorted by flow cytometry into single cell plates. The antibody genes of the ASCs are then amplified by RT-PCR and nested PCR, cloned into expression vectors and transfected into a human cell line. The expressed antibodies can then be purified and assayed for binding and neutralization. This method uses established techniques but is novel in their combination and application. This protocol can be completed with as little as 20 ml of human blood and in as little as 28 d when optimal. Although previous methodologies to produce hmAbs, including B-cell immortalization or phage display, can be used to isolate the rare specific antibody even years after immunization, in comparison, these approaches are inefficient, resulting in few relevant antibodies. Although dependent on having an ongoing immune response, the approach described herein can be used to rapidly generate numerous antigen-specific hmAbs in a short time.

This study uses structural equation modeling to examine the influence of academic motivation on reported prior cheating behavior, neutralization tendencies, and likelihood of future cheating among accounting majors. It also investigates the impact of prior cheating on neutralization of cheating behaviors and the likelihood of future cheating, as well as the potential mediating effects of neutralization on future cheating behavior. Our results support differentiation of the theoretical constructs within the specified process model, and also show significant positive associations between an amotivational orientation and prior cheating, neutralization, and the likelihood of future cheating.

The neurology and neurosurgery clinical clerkship experience (excluding lectures and conferences) of the students in U.S. allopathic medical schools during one of the academic years 1986 to 1987 or 1987 to 1988 was surveyed. Almost all schools have at least some students taking these clerkships. The majority of students (78%) have clinical exposure to neurology, but only a minority (28%) take a neurosurgical clerkship; however, far more schools require their students to take neurology clerkships (54%) than neurosurgical clerkships (12%). A few require that either be taken. Overall, 81% of schools require all students to take at least one of these clerkships. For the most part, students taking a clerkship in either specialty do not do so again. The initial and usually unique exposure averages 3.5 weeks in neurology and 2.4 weeks in neurosurgery. For each specialty, required clerkships tended to be shorter than selective clerkships, which in turn were shorter than elective ones. Furthermore, first clerkships offered in the fourth year, whether they were required, selective, or elective, tended to be longer than the corresponding third-year first clerkships at other schools. Whereas the average length of a first clinical clerkship in neurology is almost as long for schools requiring it (3.4 wk) as for those that offer it as an elective or selective (4.0 wk), required neurosurgical clerkships are much shorter (1.5 wk) than elective or selective rotations (3.1 wk). Schools with residency training programs more frequently required students to a clerkship and, consequently, had greater numbers of students taking a clerkship in the corresponding specialty.(ABSTRACT TRUNCATED AT 250 WORDS)

The specific aim of this study was to extend the analysis of [U.S.] retirement migration patterns to older Blacks. The 1980 Census public use sample A provided the data for this analysis. Because of their strong initial southern settlement and their labor force out-migration patterns in this century many older Black migrants are provincial return migrants to the South a migrant type that may decline among Blacks in the future. There is also a regional counterstream migration pattern among older Black migrants. Out-migrants in this stream from the South have elevated indicators of dependency. Suggestions are made for other related studies of Black retirement migration. (EXCERPT)

SummaryIn response to reports of discrepant in vitro assays of high-purity concentrates, a double-blind crossover study of in vivo recovery and half-life of two brands of monoclonal-antibody-purified factor VIII concentrates (Monoclate and Hemofil-M) was performed in 23 patients with hemophilia A. In vivo recoveries were close to values predicted from the labelled unitage when plasma samples were assayed by a one-stage method. When a two-stage assay was used, lower recoveries were calculated and the recovery with Hemofil-M was slightly but significantly lower than that with Monoclate. The concentrates were re-assayed in vitro by the two-stage method. Monoclate (which is assayed by the manufacturer using a two-stage method) contained 97% of the labelled potency and Hemofil-M (which is assayed by the manufacturer using a one-stage method) contained 81% of the labelled potency. Differences in in vitro and in vivo assay methods contribute to disparities between expected and observed factor VIII recovery. Clearance of Hemofil-M was significantly faster than that of Monoclate, but volume of distribution at the steady state, mean residence time, and plasma half-disappearance times of the two concentrates were not significantly different.

A growing body of research has suggested that different models drive the composing process of skilled and less‐skilled writers. Basically, less‐skilled writers extract cues from the assignment that trigger retrieval of appropriate content from memory. The composing of better writers, on the other hand, tends to begin with writers establishing goals. Those goals centering on content and genre are achieved through application of problem‐solving operations. This process continues iteratively, restructuring the writer's recalled information until text is completed. Building on this theory, the authors have created an instructional design that encourages second graders to engage in advanced writing strategies generally not found until later grades.

Resiliency has emerged as a critical construct in areas as far ranging as child development to disaster mental health. Resiliency may be thought of as the ability to rebound, or bounce back, from adversity (Kaminsky, McCabe, Langlieb,Everly, 2007). Numerous interventions have been postulated and/or shown to enhance resiliency, e.g., journaling, social support, psychological first aid, and formal crisis intervention systems, such as Critical Incident Stress Management. As the search to develop more efficient and effective resiliency enhancement interventions continues, it becomes important to search for the mechanisms of action that actually serve to account for the ability to rebound after adversity. One such postulated mechanism is that of positive emotionality. Positive emotionality may be thought of as the presence of ambient positive emotions, as well as the ability to express positive emotions in the wake of adversity. Constructs such as confidence, optimism, and the ability to find meaning may underlie such expressions. This investigation attempted to assess the relationship between the expression of ambient emotions (within the last few weeks) upon measures of burnout, job satisfaction, perceived performance, and intention to leave one's job. This study represents a randomized sample of 2,500 out of approximately 91,333 potential subjects. Four hundred eighty-nine and four hundred ninety-one usable responses were received for inclusion in the analyses. Correlational analyses revealed that expressed positive emotions, as well as expressed negative emotions, were related to the outcome variables in a significant but complementary manner.

Students make choices about academic majors based on a limited number of factors and with little apparent consideration of what may be meaningful or purposeful to them. This study examines the perc...

Venous thromboembolism (VTE) is three-fold higher among FV Leiden (FVL) carriers receiving oral contraceptives (OCPs) than in the general population. FVL screening, however, is not routinely performed before prescribing OCP, and the cost-effectiveness of this strategy is unknown. A decision tree model was constructed to evaluate FVL screening and prophylactic anticoagulation (AC) strategies in female relatives of FVL carriers. In the model, AC was low molecular weight heparin, given warfarin embryopathy risks. VTE morbidity, mortality, and other clinical parameters were obtained from published studies. Drug costs were based on average wholesale price, and counseling included VTE risk with OCP use and FVL status. Outcomes included medical costs, effectiveness measured as quality-adjusted-life-years (QALY), and the incremental cost-effectiveness ratio (ICER) over 30 years, with cost and effectiveness discounted at 3%/year. FVL screening and counselling without prophylactic AC cost less and was more effective than no screening in this population, but was less effective than screening, counselling, and prophylaxis during high-risk periods, which gained 0.083 QALY, for an ICER of $147/QALY gained. Screening with counselling and long-term AC cost $3,536 with minimal QALY gain and an ICER$600,000/QALY. Screening, OCP counseling, and prophylactic AC during high-risk periods was favoured and cost$20,000/QALY, unless: (a) high-risk prophylaxis cost$4,231 (base $932), (b) long-term prophylaxis cost$1199 (base $6,546), or (c) VTE relative risk reduction with prophylaxis was21% (base 90%). In conclusion, screening, counselling and prophylactic AC during high-risk periods in female relatives of FVL carriers is an economically favourable strategy.

Objective To address the cost-effectiveness of thrombophilia testing and treatment strategies among children with a first episode of thrombosis. Study design A 2-year Markov model was developed to evaluate the cost-utility of 3 strategies: (1) no testing, anticoagulate for 3 months, (2) no testing, anticoagulate for 6 months, and (3) testing, anticoagulate 3 or 6 months, based on results. We performed a literature search to estimate clinical probabilities and obtained quality-of-life and cost data from published sources. Results Total costs per patient were $7900 for no test, treat for 3 months; $8900 for test, treat based on results; and $12 100 for no test, treat for 6 months. Three months of treatment without testing was the least expensive strategy and also the most effective (1.74 quality-adjusted life-years) by 0.01 to 0.03 quality-adjusted life-years. Cost-utility ratios were sensitive to variation in hospitalization and medication costs, but 3 months, no testing, always remained the preferred choice. Conclusions Universal thrombophilia testing after a first episode of thrombosis is not cost-effective when used solely to determine anticoagulation duration. Therefore, a full panel of thrombophilia studies does not need to be an automatic response at the time of any deep venous thrombosis diagnoses.

Background.Standing order programs (SOPs), which allow for vaccination without an individual physician order, are the most effective mechanism to achieve high vaccination rates. Among the suggested settings for the utilization of SOPs are hospital inpatient units, because they provide care for those most likely to benefit from vaccination. The cost-effectiveness of this approach for elderly hospitalized persons is unknown. The purpose of this study was to estimate the cost-effectiveness of SOPs for pneumococcal polysaccharide vaccine (PPV) vaccination for patients 65 years of age or older in 2 types of hospital.Methods.In 2004, a 1,094-bed tertiary care hospital implemented a pharmacy-based SOP for PPV, and a 225-bed community hospital implemented a nursing-based SOP for PPV. Newly admitted patients 65 years of age or older were screened for PPV eligibility and then offered PPV. Vaccination rates before and after initiation of SOPs in the United States, incidence rates of invasive pneumococcal disease in the United States, and US economic data were the bases of the cost-effectiveness analyses. One-way and multivariate sensitivity analyses were conducted.Results.PPV vaccination rates increased 30.5% in the tertiary care hospital and 15.3% in the community hospital. In the base-case cost-effectiveness analysis, using a societal perspective, we found that both pharmacy-based and nursing-based SOPs cost less than $10,000 per quality-adjusted life-year gained, with program costs (pharmacy-based SOPs cost $4.16 per patient screened, and nursing-based SOPs cost $4.60 per patient screened) and vaccine costs ($18.33 per dose) partially offset by potential savings from cases of invasive pneumococcal disease avoided ($12,436 per case). Sensitivity analyses showed SOPs for PPV vaccination to be cost-effective, compared with PPV vaccination without SOPs, unless the improvement in vaccination rate was less than 8%.Conclusion.SOPs do increase PPV vaccination rates in hospitalized elderly patients and are economically favorable, compared with PPV vaccination rates without SOPs.

Pre-existing neutralizing antibody provides the first line of defense against pathogens in general. For influenza virus, annual vaccinations are given to maintain protective levels of antibody against the currently circulating strains. Here we report that after booster vaccination there was a rapid and robust influenza-specific IgG+ antibody-secreting plasma cell (ASC) response that peaked at approximately day 7 and accounted for up to 6% of peripheral blood B cells. These ASCs could be distinguished from influenza-specific IgG+ memory B cells that peaked 14 to 21 days after vaccination and averaged 1% of all B cells. Importantly, as much as 80% of ASCs purified at the peak of the response were influenza specific. This ASC response was characterized by a highly restricted B cell receptor (BCR) repertoire that in some donors were dominated by only a few B cell clones. This pauci-clonal response, however, showed extensive intraclonal diversification from accumulated somatic mutations. We used the immunoglobulin variable regions isolated from sorted single ASCs to produce over fifty human monoclonal antibodies (mAbs) that bound to the three influenza vaccine strains with high affinity. This strategy demonstrates that we can generate multiple high affinity mAbs from humans within a month after vaccination. The panel of influenza virus specific human mAbs allowed us to address the issue of original antigenic sin (OAS) - the phenomenon where the induced antibody shows higher affinity to a previously encountered influenza virus strain compared to the virus strain present in the vaccine1. However, we found that the vast majority of the influenza virus specific mAbs showed the highest affinity for the current vaccine strain. Thus, OAS does not seem to be a common occurrence in normal healthy adults receiving influenza vaccination.

Historically, the accounting profession has concerned itself with the phenonmenology and prevalence of stress, both job-related and personal, among its members. Studies dating back to the late 1950's have ad dressed the issue of stress as a problem confronting practitioners in all aspects of the profession. The multi-faceted nature of "stress" and the disparate approaches that have been taken to assess its prevalence and intensity have resulted in a body of literature that is presently frag mented and inconclusive. The purpose of this paper is to review the stress literature in accountancy in a manner as to provide a unifying theoretical structure to the diverse constructs and measures reported. In so doing, the nature of the stress phenomenon is explored, noteworthy empirical investigations are reviewed, and directions for future empiri cal inquiries are outlined.

Effectiveness differences between outpatient pelvic inflammatory disease (PID) treatment regimens are uncertain, but significant differences in cost exist.To examine the influence of antibiotic costs on PID therapy cost-effectiveness.The authors used a Markov decision model to estimate the cost-effectiveness of recommended antibiotic regimens for PID and performed a value of information analysis to guide future research.Antibiotic costs vary between USD 43 and USD188. Pairwise comparisons, assuming a hypothetical 1% relative risk reduction in PID complications with the more expensive regimen, showed economically reasonable cost-effectiveness ratios. Value of information and sample size considerations support further investigation to detect 10% PID complication rate differences between regimens withor=USD 50 cost differences.Within the cost range of recommended regimens, use of more expensive antibiotics would be economically reasonable if relatively small decreases in PID complication rates exist. Further investigation of effectiveness differences between regimens is needed.

Pneumococcal polysaccharide vaccination (PPV) to prevent invasive pneumococcal disease (IPD) is recommended at age 65 for most persons in the US. We used a Markov model to examine alternative PPV strategies, finding that vaccination at ages 50 and 65 prevented more IPD than present vaccination policies; four decennial vaccinations were most effective. The present vaccination policy costs $3341/QALY gained, vaccinations at 50/65 cost $23,120/QALY and four vaccinations (50/60/70/80) cost $54,451/QALY; results were sensitive to vaccine uptake assumptions, with current policy no longer favored at present vaccination rates. PPV at ages 50/65 may be clinically and, depending on cost-effectiveness criterion used, economically favored over present vaccination recommendations.

The discovery of lymphocytes bearing two light chains in mice carrying self-reactive antibody transgenes has challenged the “one lymphocyte–one antibody” rule. However, the extent and nature of allelically included cells in normal mice is unknown. We show that 10% of mature B cells coexpress both Igκ alleles. These cells are not the result of failure in allelic exclusion per se, but arise through receptor editing. We find that under physiological conditions, editing occurs both by deletion and by inclusion with equal probability. In addition, we demonstrate that B lymphocytes carrying two B-cell receptors are recruited to germinal center reactions, and thus fully participate in humoral immune responses. Our data measure the scope of allelic inclusion and provide a mechanism whereby autoreactive B cells might “escape” central tolerance.

This study examined the construct and discriminant validity of stress arousal and burnout as measured on the Stress Arousal Scale and the multidimensional role-specific version of the Maslach Burnout Inventory, respectively. The analyses utilized data from 148 individuals randomly selected from a database of 563 respondents to a larger study. The sample responded to a survey sent to members of the American Institute of Certified Public Accountants (AICPA). Sample size used in this study fell within Loehlin's 1992 prescription that for confirmatory factor analysis with two to four factors, a minimum of 100 to 200 cases should be collected. Forty-six respondents indicated that they were partners, principals, or sole practitioners in accounting firms, and 103 indicated that they were staff members (juniors, seniors, or managers). Latent variables were first constructed for the stress arousal and burnout factors. Confirmatory factor analysis was then conducted on the scale data to assess whether the factors would load on their respective underlying theoretical constructs. Finally, a nested model constraining stress arousal and burnout to load on one underlying construct was tested against the hypothesized two-factor model. The results indicated good model fit for the two-factor model and a significant loss of fit for the one-factor model, thus providing strong support for the conceptualization of stress arousal and burnout as distinct constructs.

Patients with multiple sclerosis (MS) can exhibit an exceptionally wide variety of symptoms. This is largely due to the semi-random distribution of the lesions in the central nervous system (CNS). Most lesions occur in apparently "silent" areas in the brain, and so cause no detectable symptoms. The disease is therefore much more active than a mere clinical monitoring would suggest. Most symptoms are related to a loss of function. During the relapses, this is due to a failure of axonal conduction at the site of the lesion(s). The conduction block is caused by the local demyelination which prevents the saltatory conduction but also seemingly, to some extend, by the inflammation per se. Remissions are related to a recovery of function of the affected axons owing to a spreading of sodium channels along the demyelinated axolemma but also to cerebral functional plasticity and remyelination. However, nerve conduction remains slower and less secure than normal, easily altered by physico-chemical changes such as the increase in body temperature (Uhthoff's phenomenon). Remission is incomplete when the lesion has led to axonal transaction and therefore axonal loss. Progression in MS is mainly related to "slow-burning" diffuse and chronic axonal loss in a toxic inflammatory milieu. Lastly, some symptoms in MS are so-called "positive" arising from an acquired hyperexcitability of demyelinated axons and occur either spontaneously (e.g. paresthesias) or mechanically (e.g. Lhermitte's sign).

Low-molecular-weight heparin (LMWH) appears to be safe and effective for treating pulmonary embolism (PE), but its cost-effectiveness has not been assessed.We built a Markov state-transition model to evaluate the medical and economic outcomes of a 6-day course with fixed-dose LMWH or adjusted-dose unfractionated heparin (UFH) in a hypothetical cohort of 60-year-old patients with acute submassive PE. Probabilities for clinical outcomes were obtained from a meta-analysis of clinical trials. Cost estimates were derived from Medicare reimbursement data and other sources. The base-case analysis used an inpatient setting, whereas secondary analyses examined early discharge and outpatient treatment with LMWH. Using a societal perspective, strategies were compared based on lifetime costs, quality-adjusted life-years (QALYs), and the incremental cost-effectiveness ratio.Inpatient treatment costs were higher for LMWH treatment than for UFH (dollar 13,001 vs dollar 12,780), but LMWH yielded a greater number of QALYs than did UFH (7.677 QALYs vs 7.493 QALYs). The incremental costs of dollar 221 and the corresponding incremental effectiveness of 0.184 QALYs resulted in an incremental cost-effectiveness ratio of dollar 1,209/QALY. Our results were highly robust in sensitivity analyses. LMWH became cost-saving if the daily pharmacy costs for LMWH weredollar 51, ifor = 8% of patients were eligible for early discharge, or ifor = 5% of patients could be treated entirely as outpatients.For inpatient treatment of PE, the use of LMWH is cost-effective compared to UFH. Early discharge or outpatient treatment in suitable patients with PE would lead to substantial cost savings.

The optimal duration and intensity of warfarin therapy after a first idiopathic venous thromboembolic event are uncertain. We used decision analysis to evaluate clinical and economic outcomes of different anticoagulation strategies with warfarin.We built a Markov model to assess 6 strategies to treat 40- to 80-year-old men and women after their first idiopathic venous thromboembolic event: 3-month, 6-month, 12-month, 24-month, and unlimited-duration conventional-intensity anticoagulation (International Normalized Ratio, 2-3) and unlimited-duration low-intensity anticoagulation (International Normalized Ratio, 1.5-2). The model incorporated age- and sex-specific clinical parameters, utilities, and costs. Using a societal perspective, we compared strategies based on quality-adjusted life-years (QALYs), lifetime costs, and incremental cost-effectiveness ratios.In our baseline analysis, incremental cost-effectiveness ratios were lower in younger patients and in men, reflecting the higher bleeding risk at older ages, and the lower risk of recurrence among women. Based on a willingness-to-pay of$50000/QALY, the 24-month strategy was most cost-effective in 40-year-old men ($48805/QALY), while the 6-month strategy was preferred in 40-year-old women ($35977/QALY) and 60-year-old men ($29878/QALY). In patients aged/=80 years, 3-month anticoagulation was less costly and more effective than other strategies. Cost-effectiveness results were influenced by the risks associated with recurrent venous thromboembolism, the major bleeding risk of conventional-intensity anticoagulation and the disutility of taking warfarin.Longer initial conventional-intensity anticoagulation is cost-effective in younger patients while 3 months of anticoagulation is preferred in elderly patients. Patient age, sex, clinical factors, and patient preferences should be incorporated into medical decision making when selecting an appropriate anticoagulation strategy.

Presentation of antigen to T cells represents one of the central events in the engagement of the immune system toward the defense of the host against pathogens. Accordingly, understanding the mechanisms by which antigen presentation occurs is critical toward our understanding the properties of host defense against foreign antigen, as well as insight into other features of the immune system, such as autoimmune disease. The entire antigen-presentation event is complex, and many features of it remain poorly understood. However, recent studies have provided evidence showing that glycolipid-enriched membrane rafts are important for efficient antigen presentation; the studies suggest that one such function of rafts is trafficking of antigen-MHC II complexes to the presentation site on the surface of the antigen-presenting cell. Here, we present a critical discussion of rafts and their proposed functions in antigen presentation. Emerging topics of rafts and antigen presentation that warrant further investigation are also highlighted.

Purpose Recent advances in the diagnosis and treatment of influenza, such as rapid testing and neuraminidase inhibitor therapy, are available, but their place in clinical practice and their cost-effectiveness have not been determined. Materials and methods To estimate the cost-effectiveness of these newer interventions, we used a decision model that compared several influenza management strategies: no testing or treatment, amantadine or rimantadine treatment without testing, testing then amantadine or rimantadine treatment, neuraminidase inhibitor treatment without testing, or testing then neuraminidase inhibitor treatment. Antiviral therapy began within 48 hours in febrile patients with characteristic symptoms of influenza. We assumed that antiviral treatment did not change rates of influenza complication or mortality, and chose parameter values in the baseline analysis to bias slightly against antiviral treatment and toward testing strategies. Results In the baseline analysis, testing strategies are more expensive and less effective than treatment strategies. Amantadine costs $9.06 per illness day avoided or $11.60 per quality-adjusted day gained. Compared with amantadine, zanamivir costs $198 per illness day avoided or $185 per quality-adjusted day gained, whereas oseltamivir costs $252 per illness day avoided or $235 per quality-adjusted day gained. In elderly patients who require reduced dosage, rimantadine costs $128 per quality-adjusted day gained compared with amantadine. In younger patients, amantadine is favored if the likelihood of influenza A is >67%; otherwise, neuraminidase inhibitors are favored. Testing strategies are more costly and less effective when the influenza probability is >30%. No testing or treatment is favored if the influenza probability is 0.77. In elderly patients, amantadine is favored over rimantadine if the utility of medication side effects is >0.94. Conclusion Antiviral treatment of influenza without rapid testing is reasonable economically in febrile patients with typical symptoms during influenza season. The choice of antiviral agent depends on age, the likelihood of influenza A, and the willingness to pay per quality-adjusted day gained.

We describe herein a protocol for the production of antigen-specific human monoclonal antibodies (hmAbs). Antibody-secreting cells (ASCs) are isolated from whole blood collected 7 d after vaccination and sorted by flow cytometry into single cell plates. The antibody genes of the ASCs are then amplified by RT-PCR and nested PCR, cloned into expression vectors and transfected into a human cell line. The expressed antibodies can then be purified and assayed for binding and neutralization. This method uses established techniques but is novel in their combination and application. This protocol can be completed with as little as 20 ml of human blood and in as little as 28 d when optimal. Although previous methodologies to produce hmAbs, including B-cell immortalization or phage display, can be used to isolate the rare specific antibody even years after immunization, in comparison, these approaches are inefficient, resulting in few relevant antibodies. Although dependent on having an ongoing immune response, the approach described herein can be used to rapidly generate numerous antigen-specific hmAbs in a short time.

Total hip and knee replacements (THR and TKR) are high-risk settings for venous thromboembolism (VTE). This review summarizes the cost effectiveness of VTE prophylaxis regimens for THR and TKR. We searched MEDLINE (January 1997 to October 2009), EMBASE (January 1997 to June 2009) and the UK NHS Economic Evaluation Database (1997 to October 2009). We analysed recent cost-effectiveness studies examining five categories of comparisons: (i) anticoagulants (warfarin, low-molecular-weight heparin [LMWH] or fondaparinux) versus acetylsalicylic acid (aspirin); (ii) LMWH versus warfarin; (iii) fondaparinux versus LMWH; (iv) comparisons with new oral anticoagulants; and (v) extended-duration (≥3 weeks) versus short-duration (

The blood coagulation factor IX(a) binds specifically to a site on endothelial cells with a Kd of 2.0-3.0 nM. A number of previous studies have attempted to define the region(s) of factor IX(a) that mediate this interaction. These studies suggested that there are two regions of factor IX(a), the gamma-carboxyglutamic acid (Gla) domain and the epidermal growth factor like (EGF-like) domains, that mediate high-affinity binding to endothelial cells. Recently, however, the participation of the EGF1 domain has been excluded from the interaction. This indicated that if there was an EGF component of factor IX contributing to the binding affinity, then it must be in the second EGF-like domain. In order to further evaluate this relationship, we performed competitive binding experiments between 125I plasma factor IX and a set of six chimeric proteins composed of portions of factor VII and factor IX. Our data suggest that the high-affinity interaction between factor IX and the endothelial cell binding site is mediated by the factor IX Gla domain and that the factor IX EGF domains are not involved in binding specificity.

Some authorities recommend varicella antibody testing or vaccination for adults without a history of chickenpox, but the cost effectiveness of these interventions is uncertain.Using a Markov decision model, we estimated the cost effectiveness of three strategies for adults with no history of chickenpox: no vaccination, varicella antibody testing followed by vaccination for those without antibody, and vaccinating all. Societal and third-party payer perspectives were taken, with costs and benefits discounted at 3% per year. Assumptions for the baseline analysis were chosen to bias against no vaccination.In the baseline analysis for 20- to 29-year-old patients, testing followed by vaccination compared with no vaccination is cost saving from a societal perspective and costs $6,670 per quality-adjusted life-year (QALY) gained from a third-party payer perspective. When less favorable assumptions are used, results are sensitive to the rates of compliance with vaccination follow-up; testing followed by vaccination costs more than $50,000 per QALY if75% comply. For patients 30 years of age and older, the incremental cost of testing followed by vaccination is at least $97,100 per QALY compared with no vaccination, with costs greater than $50,000 per QALY unless testing costs less than $7.73, the chickenpox case-fatality rate is0.067% (baseline 0.025%), or immunity with no chickenpox history is25% (baseline 71%). In either age group, vaccinating all has an incremental cost of $2 to $16 million per QALY gained compared with testing followed by vaccination.Testing followed by vaccination for varicella in US adults aged 20 to 29 years may be cost effective by conventional criteria but is sensitive to rates of compliance with vaccination protocols. Testing or vaccination of older adults is expensive but may be cost effective in patients with lower probabilities of immunity or in those who have a greater risk of complications from chickenpox.

The interaction between vitamin K-dependent protein S and the C4b-binding protein (C4BP) was studied using surface plasmon resonance and genetic engineering. The affinity, as well as association and dissociation rates of the complex, was measured for human and bovine protein S at five different calcium concentrations. The binding to C4BP of six protein hybrids containing different parts of coagulation factor IX and protein S was studied in the absence and presence of calcium. The results show that dissociation of the human protein S-C4BP complex is extremely slow in the presence of > or = 10 microM calcium (k(off) = 7 x 10(-6) s(-1)) and the association rate constant is k(on) = 7 x 10(4) M(-1) s(-1). Human and bovine protein S were found to bind to human C4BP with the same affinity, K(D) = 0.1 nM, but the rates of association and dissociation were higher for the bovine protein S (k(on) = 2 x 10(5) M(-1) s(-1), k(off) = 2 x 10(-5) s(-1)). In the absence of calcium, the affinity for C4BP was reduced by a factor of 65 for human protein S and by a factor of 40 for bovine protein S. The decreased affinity could be mainly attributed to an increased off-rate (12-17-fold), while the on-rate decreased 3-4-fold. The studies using chimeric proteins show that the portion of protein S that is responsible for binding to C4BP is fully contained in the two laminin-G-type repeats, which are homologous to the sex hormone binding globulin (SHBG). All hybrids that contain the laminin-G-type repeats bind to C4BP with the same affinity as recombinant protein S, whereas hybrids lacking these repeats show no detectable binding to C4BP. The present data also suggest that the effect of calcium on the C4BP-binding properties is mediated by calcium binding site(s) in the laminin-G-type repeats.

Background Sickle cell disease (SCD) is the most common inherited blood disorder in the U.S., affecting 100,000 individuals, including 1 in 500 African Americans. Previous studies have shown that individuals with SCD have a higher rate of venous thromboembolism (VTE) than those without SCD. Women with SCD experience a higher rate of pregnancy-related complications, including a 2-fold higher VTE risk during pregnancy than unaffected women, and VTE is the major cause of maternal death in SCD. Further, among pregnant SCD patients with prior SCD complications, including pneumonia, vaso-occlusive disease, and/or acute chest syndrome, there is a 2-fold higher VTE risk (6%) than in those with SCD alone (3%). Yet, there are no guidelines on thromboprophylaxis in pregnant women with SCD; in fact, the American College of Chest Physicians guidelines do not address pregnant women with SCD. As VTE risk may be higher in pregnant women with SCD and the risk of bleeding is not known to be increased, we examined the cost-effectiveness of thromboprophylaxis to reduce pregnancy-associated VTE risk in women with SCD. Methods We constructed a Markov state-transition model using TreeAge Pro Suite 2013 comparing, in a hypothetical cohort of pregnant women with SCD and no previous VTE, prophylactic anticoagulation (AC) with enoxaparin, the anticoagulant of choice in pregnancy, to a strategy of no prophylactic AC. SCD pregnancies with previous pneumonia, vaso-occlusive disease, acute chest syndrome, and higher VTE risk were also assessed. The model was run over 15 months to account for acute VTE onset and treatment throughout pregnancy and postpartum. In the prophylactic AC strategy, pregnant women with SCD entered the model and prophylactic AC was continued throughout the pregnancy until 2 months postpartum. Transitions were simulated between several health states, including well, VTE, major bleeding, minor bleeding, and death. VTE risks and costs, major and minor bleeding rates, mortality rates, and quality of life utilities were obtained from the literature. The model analyzed antepartum and postpartum costs of prophylactic AC, as well as survival benefits. The outcomes included direct medical costs, effectiveness measured by VTE reduction, quality-adjusted life-years (QALY), and the incremental cost-effectiveness ratio (ICER). We also conducted a sensitivity analysis to assess the cost-effectiveness of varying baseline estimates within plausible ranges. Results Prophylactic AC in pregnant women with SCD cost less than $100,000/QALY gained when prophylactic AC cost less than $561 per month or when VTE risk exceeded 4.97%. For example, in women with SCD in whom the risk of VTE is ≥ 6.0%, i.e., those with prior SCD complications, prophylactic AC cost $76,811/QALY gained, well within the acceptable range. Results were much less sensitive to variation of other model parameters. Discussion For pregnant women with SCD, enoxaparin thromboprophylaxis is economically reasonable when the cost of enoxaparin is < $561 per month or the risk of VTE is > 5%, such as among pregnant women with SCD and prior pneumonia, vaso-occlusive disease, and/or acute chest syndrome. If high VTE rates are confirmed in prospective studies, enoxaparin thromboprophylaxis may be beneficial and economically reasonable in pregnant women with SCD. Disclosures: No relevant conflicts of interest to declare.

Purpose: To demonstrate an increase spin‐spin relaxation time (T2) of hyperpolarized carbon‐13 urea by nitrogen‐15 labeling its amide groups, and to show how this enables background‐free perfusion MRI at 1 mm in‐plane resolution with SNR > 300. Methods: In vivo hyperpolarized dual‐labeled [C13,N‐15]urea and singly‐labeled [C13]urea images were acquired dynamically in a rat using a using a steady state free precession (SSFP) and fast low angle shot (FLASH) acquisitions on a clinical 3T MRI scanner. Dynamic images were fit pixel‐wise to an exponential function to create effective decay constant maps. T2 measurements using Carr Purcell Meiboom Gill (CPMG) sequences on hyperpolarized samples were also performed. Results: Measured T2 values were 90±15 ms for [C13]urea and 24±4 s for [C13,N‐15]urea; the in vivo estimate of the T2 of [C13,N‐15]urea was 1.4 s. Concordant with analytic signal models, hyperpolarized imaging with [C‐13,N‐15] urea showed SNR improvements of 5.1±2.3 and 3.5±1.1 compared to [C13]urea imaged with FLASH and SSFP respectively. Exponential decay maps showed delineation of the renal cortex, medulla, and pelvis, with renal columns (medullary cortical extensions) visible. Conclusion: The large SNR gain achievable using [C13,N‐15]urea could be utilized for a corresponding resolution enhancement, which greatly improves the image quality when using this completely endogenous probe. This probes low toxicity could enable contrast angiography on patients with diminished renal function, even with large intravenous doses. Since clinical MRI scanners have longer minimum repetition time requirements due to safety and hardware constraints, the long T2 of [C13,N‐15]urea measured in this study facilitates SSFP or spin echo train imaging of hyperpolarized for clinical applications. The delineation of the renal structures suggests a possible application of renal function assessment.

Metal binding sites within the Gla domain of vitamin K-dependent coagulation factors have been divided into nonspecific metal sites and calcium-specific sites. We demonstrate here that five residues within the Gla domain of factor IX are responsible for the reactivity with the metal-dependent factor IX monoclonal antibody, A-7. First we demonstrate that modifying any one of three residues within this site in factor IX abolishes the binding of A-7. To confirm the specificity of the antibody, the Gla domain of factor VII was changed at residues 32, 33, 34, 38 and 39 to the homologous residues of human factor IX. These changes were sufficient to generate a factor VII Gla domain with an A-7 binding site of the same affinity as that in factor IX. The site identified is one of the two major surfaces of the Gla domain and may represent the metal-dependent binding site.

Factor IX and factor X have sialic acid in O-linked and N-linked oligosaccharides on their activation peptides, and a terminal sialic acid is found on a recently described O-linked tetrasaccharide at Ser-61 in the light chain of human factor IXa. In studies presented here, the potential role of sialic acid residues in mediating activity of human coagulation factors IX and X was tested after enzymatic removal of sialic acid residues. In contrast to previous reports, treatment of factor IX or factor IXa with recombinant sialidase did not decrease the rate of factor IX activation or proteolytic properties of human factor IXa. The activation rates of factor IX and desialated factor IX were indistinguishable when treated with factor XIa, with factor VIIa/tissue factor complex, and with the factor X activating enzyme from Russell's viper venom. Desialated human factor IXa showed full activity in the non-activated partial thromboplastin time assay and retained full "tenase" activity in a coupled amidolytic assay. Similar experiments with human factor X showed no detectable loss of clotting activity in the prothrombin time assay after desialation. Additionally, desialated human factor X was cleaved by the factor X activating enzyme from Russell's viper venom and intrinsic tenase at the same rate as untreated factor X when analyzed by SDS-polyacrylamide gel electrophoresis. These studies have shown that factor IX and factor X clotting activity are not dependent on sialic acid content. Further studies are needed to determine whether desialated factor IX binds to endothelial cells, and whether factors IX and X are more rapidly cleared from circulation or have altered susceptibility to proteolysis after enzymatic removal of sialic acid.

Abstract 3177 Background: Rivaroxaban is an oral anticoagulant administered once daily that works by direct inhibition of factor Xa. It has been found to be noninferior to warfarin in the prevention of recurrent venous thromboembolism (VTE). Whether rivaroxaban is cost effective in the prevention of recurrent VTE, however, is not known. Methods: To assess the cost effectiveness of rivaroxaban compared with warfarin in the prevention of recurrent VTE, we built a Markov state transition model over a 10-year time horizon. The base case analysis consisted of a hypothetical cohort of 60-year-old patients who were diagnosed with their first VTE and received secondary prophylaxis with either rivaroxaban or warfarin for 6 months. Cost estimates were derived from the Healthcare and Utilization Project (HCUP) and other sources. Probabilities for VTE recurrence and mortality and for major and minor bleeding were based on the EINSTEIN PE trial (NEJM 2012; 366: 1287–97). Outcomes included costs in 2011 United States dollars, quality adjusted life years (QALYs), and incremental cost effectiveness ratios (ICERs) over 10 years from a societal perspective. Results: Base case results are shown in the Table, showing total medication and other medical costs associated with each strategy. Compared with warfarin, the rivaroxaban strategy cost less ($4057 vs $7004) and was more effective (9.30 QALYs vs 9.16 QALYs). Thus, warfarin was dominated by rivaroxaban. In sensitivity analyses, results were most sensitive to changes in the probability of major bleeding with rivaroxaban. As shown in the Figure, when major bleeding with rivaroxaban (base case 1.1%) was less than 4.5%, the ICRE was within the $100,000 per QALY gained acceptability threshold range. Results favoring rivaroxaban were robust to individual variation of other parameter values. Conclusion: Prophylactic anticoagulation with rivaroxaban appears to be a cost effective, and perhaps cost saving, alternative to warfarin for the prevention of recurrent VTE. Disclosures: Off Label Use: Rivaroxaban - Prevention of recurrent venous thromboembolism.

H3N2 influenza viruses have now circulated in the human population for 43 years since the pandemic of 1968, accumulating sequence changes in the hemagglutinin (HA) and neuraminidase (NA) that are believed to be predominantly due to selection for escape from antibodies. Examination of mutations that persist and accumulate led to identification of antigenically significant mutations that are contained in five antigenic sites (A-E) mapped on to the H3 HA. In early H3N2 isolates, antigenic site A appeared to be dominant while in the 1990s site B seemed more important. To obtain experimental evidence for dominance of antigenic sites on modern H3 HAs, we have measured antibodies in plasma of human subjects who received the 2006-07 trivalent subunit influenza vaccine (H3 component A/Wisconsin/67/05) or the 2008-09 formulation (H3 component A/Uruguay/716/07). Plasmas were tested against expressed HA of Wisconsin-like influenza A/Oklahoma/309/06 and site-directed mutants in antigenic site A (NNES121-124ITEG, N126T, N133D, TSSS135-138GSNA, K140I, RSNNS142-146PGSG), and antigenic site B (HL156-157KS, KFK158-160GST, NDQI189-192QEQT, A196V). "Native ELISA" analysis and escape mutant selection with two human monoclonal antibodies demonstrated that antibody E05 binds to antigenic site A and 1_C02 binds to site B. We find that most individuals, after vaccination in seasons 2006-07 and/or 2008-09, showed dominance of antigenic site B recognition over antigenic site A. A minority showed dominance of site A in 2006 but these were reduced in 2008 when the vaccine virus had a site A mutation. A better understanding of immunodominance may allow prediction of future antigenic drift and assist in vaccine strain selection.

Factor IX consists of a gamma-carboxyglutamic acid-rich domain followed by two epidermal growth factor (EGF)-like domains and the C-terminal protease domain. To delineate the function of EGF1 domain in factor IX, we constructed three mutants: an EGF1 domain-deleted mutant (IX delta EGF1), a point mutant (IXQ50P) with a Gln-50-->Pro change, and a replacement mutant (IXPCEGF1) in which the EGF1 domain of factor IX was replaced by that of protein C. These mutants and wild-type (WT) factor IX (IXWT) were expressed in 293 kidney cells by using pRc/CMV vector. The purified proteins had the same gamma-carboxyglutamic acid content as the normal plasma factor IX (IXNP) and were activated normally by factor XIa-Ca2+. In contrast, IX delta EGF1 could not be activated by factor VIIa-tissue factor-Ca2+, and the activation of IXPCEGF1 in this system was markedly slow; however, IXQ50P was activated at a normal rate. In additional studies, both IXWT and IX delta EGF1 were rapidly converted to their respective IX alpha forms by factor Xa-phospholipid-Ca2+. Since this reaction has an absolute requirement for phospholipid, it indicates that the mutants under study are not impaired in their interactions with phospholipid. Relative coagulant activities of factor XIa-activated proteins were IXNP, 100%; IXWT, 75-85%; IX delta EGF1, < or = 1%; IXPCEGF1, < or = 2%; and IXQ50P, 6-10%. We conclude that the EGF1 domain of factor IX is required for its activation by factor VIIa-tissue factor and that the Gln-50 residue is not critical for this activation. Further, the EGF1 domain of factor IX is not essential for phospholipid binding and for its activation by factor XIa. In addition, the low coagulant activities of the activated mutants indicate that the EGF1 domain is also important in factor X activation by factor IXa-factor VIIIa-Ca(2+)-phospholipid complex.