The von Willebrand factor predicted unpaired cysteines are essential for secretion.

BACKGROUND: von Willebrand factor (VWF) contains free thiols that mass spectroscopy has located to nine cysteines: two in the D3 domain (Cys889 and Cys898) and seven in the C domains (Cys2448, Cys2451, Cys2453, Cys2490, Cys2491, Cys2528, and Cys2533) (J Biol Chem, 7, 2007, 35604; Blood, 118, 5312). It has been suggested that these free thiols function to regulate the self-association of VWF through thiol-disulfide exchange (J Biol Chem, 7, 2007, 35604; Blood, 118, 5312). However, recent structural modeling has predicted that these cysteines are, in fact, disulfide-bonded (Blood, 118, 5312; Blood, 120, 449). OBJECTIVES: To use mutation and expression analyses to investigate how these conflicting reports might be compatible with the synthesis and expression of VWF. METHODS AND RESULTS: Both full-length VWF and VWF fragments with cysteine to alanine mutations of the nine cysteines and two predicted binding partners (Cys2431 and Cys2468) failed to secrete. Mutation of a cysteine pair, C2431A/C2453A, similarly resulted in a failure to secrete, indicating that this is not secondary to creation of an unpaired thiol. Deletion mutants containing seven of these cysteines, conforming to hypothesized domain boundaries, also failed to secrete: ∆C1C6 (2255-2720), ∆C3C4 (2429-2577), ∆C3 (2429-2496), and ∆C4 (2497-2577). Analysis of cell lysates and immunofluorescence confirmed that the mutants were retained within the endoplasmic reticulum (ER). Coexpression with wild-type VWF rescued secretion of some mutants to a limited extent. CONCLUSIONS: These data suggest: first, that pairing of cysteines implicated in free thiol exchange is essential for correct folding of the VWF molecule, and unpairing must occur following exit from the ER or secretion from the cell; and second, that intact C domains are essential for efficient VWF secretion and must interact in the ER.

Assessing pesticide safety knowledge among Hispanic migrant farmworkers in Oregon.

The purpose of this article is to report on the development and initial use of a pesticide knowledge test (PKT) specifically designed to evaluate agricultural workers' knowledge of the content mandated by the federal Worker Protection Standard (WPS). The PKT is a 20-item, true-false test, used in a sample of 414 adult and adolescent migrant farmworkers in Oregon. The overall mean score, i.e., number correct, was 15.67(78.4%), with both adults and adolescents demonstrating the most difficulty with questions related to the overall health effects of pesticides. The internal consistency was 0.73, when estimated using a method to correct for small sample sizes. Only six items had less than 70% correct answers. Content validity was achieved by basing the items directly on the Worker Protection Standard; face validity was obtained by having the final version of the test reviewed by a bilingual (English-Spanish) educator familiar with the requirements of the WPS. Overall, adult participants scored better than adolescents, and those with previous pesticide training scored better than those without. There were no differences in scores based on gender or whether the test was taken in English or Spanish; however, participants who spoke indigenous languages scored significantly lower than those who did not. These results indicate that the PKT is a valid, reliable measure of worker knowledge of the content of the WPS, although it does not measure the extent to which that knowledge is actually used in the work setting.

Telemedicine for the Medicare population: pediatric, obstetric, and clinician-indirect home interventions.

BACKGROUND: This report is a supplement to an earlier evidence report, Telemedicine for the Medicare Population, which was intended to help policymakers weigh the evidence relevant to coverage of telemedicine services under Medicare. That report focused on telemedicine programs and clinical settings that had been used with or were likely to be applied to Medicare beneficiaries. While we prepared that report, it became apparent that there are also telemedicine studies among non-Medicare beneficiaries--e.g., children and pregnant women--that could inform policymakers and provide more comprehensive evidence of the state of the science regarding telemedicine applications. In addition, the first evidence report only partially included a class of telemedicine applications (called self-monitoring/testing telemedicine) in which the beneficiary used a home computer or modern-driven telephone system to either report information or access information and support from Internet resources and indirectly interact with a clinician. Self-monitoring/testing applications in the first report required direct interaction with a clinician. The goal of this report is to systematically review the evidence in the clinical areas of pediatric and obstetric telemedicine as well as home-based telemedicine where there is indirect involvement of the health care professional. (In this report, we will refer to the latter as clinician-indirect home telemedicine.) Specifically, the report summarizes scientific evidence on the diagnostic accuracy, access, clinical outcomes, satisfaction, and cost-effectiveness of services provided by telemedicine technologies for these patient groups. It also identifies gaps in the evidence and makes recommendations for evaluating telemedicine services for these populations in the future. The evidence is clustered according to three categories of telemedicine service defined in our original report: store-and-forward, self-monitoring/testing, and clinician-interactive services. The three clinical practice areas reviewed in this report are defined as follows. The term pediatric applies to any telemedicine study in which the sample consisted wholly or partially of persons aged 18 or younger, including studies with neonatal samples. The term obstetric applies to any telemedicine study in which the sample consisted entirely of women seeking pregnancy-related care. The term clinician-indirect home telemedicine applies to home-based telemedicine (called self-monitoring/testing in our original report) where a telemedicine application used in the home has only indirect involvement by the health care professional. Interactive home telemedicine was applied in this report to all patient populations. KEY QUESTIONS: The key questions that served as a guide for reviewing the literature in the evaluation of pediatric, obstetric, and clinician-indirect home telemedicine applications were derived by consensus among the evidence-review team based on the analytic framework established for the original evidence report. For the current report, the questions were applied to studies in all three practice areas as a whole group within each of the three categories of telemedicine services: store-and-forward; self-monitoring/testing; and clinician-interactive. The specific key questions were: 1. Does telemedicine result in comparable diagnosis and appropriateness of recommendations for management? 2. Does the availability of telemedicine provide comparable access to care? 3. Does telemedicine result in comparable health outcomes? 4. Does telemedicine result in comparable patient or clinician satisfaction with care? 5. Does telemedicine result in comparable costs of care and/or cost-effectiveness? METHODS: We searched for peer-reviewed literature using several bibliographic databases. In addition, we conducted hand searches of leading telemedicine journals and identified key papers from the reference lists of journal articles. For our original evidence report on telemedicine for the Medicare population, we designed a search to find any publications about telemedicine and used it to search the MEDLINE, CINAHL, and HealthSTAR databases for all years the databases were available. Through this process, we captured studies of pediatric, obstetric, and clinician-indirect home telemedicine; however, they were excluded from the original report since they were outside its scope. For this supplemental report, we reviewed our original search results and identified studies relevant to this report. We identified additional studies from the reference lists of included papers and from hand searching two peer-reviewed telemedicine publications, the Journal of Telemedicine and Telecare and Telemedicine Journal. We critically appraised the included studies for each study area and key question and discussed the strengths and limitations of the most important studies at weekly meetings of the research team. We also developed recommendations for research to address telemedicine knowledge gaps. To match these gaps with the capabilities of specific research methods, we classified the telemedicine services according to the type of evidence that would be needed to determine whether the specific goals of covering such services had been met. We emphasized the relationship between the type and level of evidence found in the systematic review of effectiveness and the types of studies that might be funded to address the gaps in knowledge in this growing field of research. FINDINGS: We identified a total of 28 eligible studies. In the new clinical areas, we found few studies in store-and-forward telemedicine. There is some evidence of comparable diagnosis and management decisions made using store-and-forward telemedicine from the areas of pediatric dental screening, pediatric ophthalmology, and neonatalogy. In self-monitoring/testing telemedicine for the areas of pediatrics, obstetrics, and clinician-indirect home telemedicine, there is evidence that access to care can be improved when patients and families have the opportunity to receive telehealth care at home rather than in-person care in a clinic or hospital. Access is particularly enhanced when the telehealth system enables timely communication between patients or families and care providers that allows self-management and necessary adjustments that may prevent hospitalization. There is some evidence that this form of telemedicine improves health outcomes, but the study sample sizes are usually small, and even when they are not, the treatment effects are small. There is also some evidence for the efficacy of clinician-interactive telemedicine, but the studies do not clearly define which technologies provide benefit or cost-efficiency. Some promising areas for diagnosis include emergency medicine, psychiatry, and cardiology. Most of the studies measuring access to care provide evidence that it is improved. Although none of these studies were randomized controlled trials, they provide some evidence of access improvement over prior conditions. Clinician-interactive telemedicine was the only area for which any cost studies were found. The three cost studies did not adequately demonstrate that telemedicine reduces costs of care (except comparing only selected costs). No study addressed cost-effectiveness. CONCLUSIONS: This supplemental report covering the areas of pediatrics, obstetrics, and indirect-clinician home telemedicine echoes the findings of our initial report for the Medicare domain, which is that while the use of telemedicine is small but growing, the evidence for its efficacy is incomplete. Many of the studies are small and/or methodologically limited, so it cannot be determined whether telemedicine is efficacious. Future studies should focus on the use of telemedicine in conditions where burden of illness and/or barriers to access for care are significant. Use of recent innovations in the design of randomized controlled trials for emerging technologies would lead to higher quality studies. Journals publishing telemedicine evaluation studies must set high standards for methodologic quality so that evidence reports need not rely on studies with marginal methodologies.

Motivations and concerns of patients with access to genetic testing for hereditary pancreatitis.

OBJECTIVES: Direct DNA testing is now available for hereditary pancreatitis (HP). This study aimed to identify the factors that motivated individuals to participate in research and to determine how research participants used their genetic test results. METHODS: A survey was mailed to 247 participants (110 male, 137 female) who were > or =18 yr of age and living in the US. Data analysis was primarily a description of frequency distribution of the responses. RESULTS: Ninety-one of 247 participants (37%) completed the survey. Of the 55 female and 36 male respondents, 60% were 31-55 yr old, and a total of 54% tested positive for HP. The most common reason for participating in research was "to help a relative/family member" (61%), and genetic testing was pursued because of "the disturbance of seeing affected relatives" (48%) and "the desire to help future generations" (33%). Perceived risk of developing HP in the future was the least important motivating factor in seeking genetic testing. Sixty-two percent of respondents had received their genetic test results. All but one chose to share their results with at least one person: most often with family members (96%) and physicians (62%), and least often with insurance companies (4%). The most common influential factor in withholding information was "the fear of insurance discrimination" (23%). CONCLUSIONS: The major motivations to participate in the HP genetic research study were to obtain genetic testing and to help current family members and future generations. The major concern was insurance discrimination. Participants clearly appreciate the availability of genetic testing for HP. These results suggest that a mechanism to disclose results to research participants should be considered, and effective ways to protect at-risk individuals from insurance discrimination must remain a genetics health care priority.

Hereditary pancreatitis in North America: the Pittsburgh-Midwest Multi-Center Pancreatic Study Group Study.

BACKGROUND: Hereditary pancreatitis (HP) was defined on a clinical basis alone until the first cationic trypsinogen gene (PRSS1) mutation was discovered through the initial phase of the current Pittsburgh Midwest Multi-Center Pancreatic Study Group (MMPSG) HP study in 1996, making genetic testing available. AIM: To evaluate the regional distribution of HP in the United States, and to compare the study's gene mutation database with the pedigree databases to determine whether family history alone predicts the likelihood of detecting mutations in the cationic trypsinogen gene. METHODS: Probands of families with HP, familial pancreatitis and idiopathic chronic pancreatitis were recruited through referrals from MMPSG collaborating centers, other physicians and self-referral of patients who had learned of the study through the World Wide Web (www.pancreas.org). Pedigrees were constructed, detailed questionnaires were completed and a blood sample was drawn for each proband and participating family members. The birthplace and current location of each patient was recorded, DNA was analyzed for known mutations and the pattern of phenotype inheritance was determined from analysis of each pedigree. RESULTS: A total of 717 individuals were ascertained; 368 (51%) had clinical pancreatitis confirmed and the rest were primarily unaffected family members used for linkage studies. Forty-six clinically unaffected individuals were silent mutation carriers (11% of mutation-positive individuals). HP was most common in Minnesota, New York and the central mid-Atlantic states plus Kentucky and Ohio. One hundred and fifteen of 150 kindreds fulfilled the strict definition of an HP family, and 60 (52%) had PRSS1 mutations. Of the families with a detected mutation, 11% did not fulfill the clinical definition of an HP kindred. CONCLUSIONS: The distribution of HP within the United States shows major regional differences. The etiology of HP can be identified in a small majority of HP families through genetic testing. However, family history alone is not a good predictor of finding a mutation in the cationic trypsinogen (PRSS1) gene.

Disparity detection in anticorrelated stereograms.

Recent physiological observations in which stimuli with opposite contrast signs in the two eyes have been used (anticorrelated stereograms) show that these stimuli evoke responses in primary visual cortex which are the reverse of responses to correlated stimuli. Psychophysical investigations reveal no such reversals: reversed-contrast bars with crossed disparities are seen in front of those with uncrossed disparities. For anticorrelated random-dot stereograms human subjects perceive no depth at all, except at low dot densities. However, these human studies were carried out with stimuli that differed in several ways from those used in physiological studies. We therefore reexamined psychophysical responses using stimuli similar to those used for physiological recordings. Our results confirm the previous findings: there is no evidence of a reversed depth sensation for bar stereograms (crossed disparities are never seen behind uncrossed disparities), and subjects are unable to detect depth in anticorrelated random-dot stereograms at the densities used for the physiological recordings. The discrepancy between the psychophysical data and the responses of single neurons in primary visual cortex suggests that further processing outside area V1 is necessary to provide the signals that produce the sensation of stereoscopic depth.

Infections following implant arthroplasties of the forefoot.

This article discusses the causes, pathogenesis, diagnosis, prevention, and treatment of infections associated with implant arthroplasties of the forefoot. Topics covered include isolated organisms, routes of infection, bacterial glycocalyx (that is, biofilm or slime layer) production, preoperative evaluation, air filtration systems, surgical technique, use of prophylactic antibiotics, inflammatory reactions (arthritic detritus, metallosis), differential diagnosis, and treatment protocols.

Right atrial myxoma with right to left shunting and mitral valve prolapse.

A 58 year old black man presented with progressive dyspnea and persistent systemic arterial hypoxemia. Initial hemodynamic evaluation revealed mitral valve prolapse and evidence for isolated right to left shunting, presumed to be extracardiac. A detailed pulmonary evaluation disclosed normal volume and flow parameters with a mild reduction of the single breath carbon monoxide diffusing capacity. An open lung biopsy disclosed no abnormalities. Radionuclide studies of the heart, however, suggested the possibility of a filling defect in the right atrium, and echocardiography enforced the impression of a mass in the right atrium, subsequently demonstrated by superior vena cava angiography. Our report outlines the use of multiple diagnostic tools in difficult situations and stresses the importance of right atrial myxoma in the differential diagnosis of isolated right to left shunting