62 research outputs found

    Control of discontinuous gas exchange in Samia cynthia: effects of atmospheric oxygen, carbon dioxide and moisture

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    The evolution of discontinuous gas exchange (DGE) in insects is highly controversial. Adaptive hypotheses which have obtained experimental support include a water savings mechanism for living in dry environments (hygric hypothesis), a reduction in oxidative damage due to a high-performance oxygen delivery system (oxidative damage hypothesis), and the need for steep intratracheal partial pressure gradients to exchange gases under the hypercapnic and/or hypoxic conditions potentially encountered in subterranean environments (chthonic hypothesis). However, few experimental studies have simultaneously assessed multiple competing hypotheses within a strong inference framework. Here, we present such a study at the species level for a diapausing moth pupa, Samia cynthia. Switching gas conditions from controlled normoxic, normocapnic and intermediate humidity to either high or low oxygen, high or low moisture, elevated carbon dioxide, or some combination of these, revealed that DGE was abandoned under all conditions except high oxygen, and high or low gas moisture levels. Thus, support is found for the oxidative damage hypothesis when scored as maintenance of DGE. Modulation of DGE under either dry or hyperoxic conditions suggested strong support for the oxidative damage hypothesis and some limited support for the hygric hypothesis. Therefore, this study demonstrates that the DGE can be maintained and modulated in response to several environmental variables. Further investigation is required using a strong-inference, experimental approach across a range of species from different habitats to determine how widespread the support for the oxidative damage hypothesis might be.Centre of Excellence for Invasion Biolog

    Patient perspectives on cervical cancer screening interventions among underscreened women

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    Background Cervical cancer is highly preventable with regular screening, yet over 4,000 women die from it annually in the United States. Over half of new cervical cancer cases in the U.S. are attributable to insufficient screening. Methods Participants were 23 low-income, uninsured or Medicaid-insured women in North Carolina who were overdue for cervical cancer screening according to national guidelines. Semi-structured interviews examined perspectives on barriers to cervical cancer screening and on interventions to reduce these barriers. We also elicited feedback on three proposed evidence-based interventions: one-on-one education, coupons to reduce out-of-pocket costs, and self-collection of samples for detection of high-risk human papillomavirus (HPV) infection, the primary cause of cervical cancer. Results Reported barriers included high cost, inconvenient clinic hours, lack of provider recommendation, poor transportation, difficulty finding a provider, fear of pain, and low perceived need. Participants suggested interventions including reducing cost, improving convenience through community-based screening or extended clinic hours, strengthening provider recommendations, and providing one-on-one counseling and education outreach. HPV self-collection was most frequently selected as the “most helpful” of 3 proposed interventions (n = 11), followed by reducing out-of-pocket costs (n = 7) and one-on-one education (n = 5). Conclusion Cost was the most reported barrier to cervical cancer screening, although women experience multiple simultaneous barriers. Novel interventions such as HPV self-collection promise to reduce some, but not all, barriers to primary screening. Interventions that work on reducing multiple barriers, including obstacles to receiving follow-up care, may be most effective to prevent cervical cancer among these high-risk women

    Reactive oxygen species production and discontinuous gas exchange in insects

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    While biochemical mechanisms are typically used by animals to reduce oxidative damage, insects are suspected to employ a higher organizational level, discontinuous gas exchange mechanism to do so. Using a combination of real-time, flow-through respirometry and live-cell fluorescence microscopy, we show that spiracular control associated with the discontinuous gas exchange cycle (DGC) in Samia cynthia pupae is related to reactive oxygen species (ROS). Hyperoxia fails to increase mean ROS production, although minima are elevated above normoxic levels. Furthermore, a negative relationship between mean _V CO2 and mean ROS production indicates that higher ROS production is generally associated with lower _V CO2 . Our results, therefore, suggest a possible signalling role for ROS in DGC, rather than supporting the idea that DGC acts to reduce oxidative damage by regulating ROS production

    Use of short messaging service to improve follow-up for abnormal pap test results in minority and medically underserved women in North Carolina: Questionnaire on attitudes and acceptability

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    Background: An estimated one in eight cervical cancer cases are due to a lack of follow-up care for abnormal Pap test results. Low rates of completion of follow-up care particularly affect low-income minority women. The burden of cervical cancer could be reduced through interventions that improve timely colposcopy follow-up and treatment of abnormal screening results. Mobile communications via text messaging present a low-cost opportunity to increase rates of clinic return among women referred to follow-up after obtaining abnormal screening results. Objective: Our aims were to determine the acceptability and feasibility of using text messaging to increase completion of follow-up care following abnormal cervical cancer screening (Pap test) results and to examine factors that may affect the acceptability and use of text messaging to increase communications between health care providers (HCP) and low-income minority women. Methods: The study participants were 15 low-income women who had undergone a Pap test within the preceding 12 months. Semistructured interviews, including open- A nd closed-ended questions from a validated questionnaire, were conducted by phone or in person. Responses to closed-ended survey items were tabulated, and descriptive statistics were generated using Microsoft Excel. Responses to the open-ended questions were coded and analyzed using NVivo 11 qualitative analysis software. Results: Nearly all participants (14/15, 93%) were comfortable receiving a text message from an HCP stating that their Pap test results were available (<40 years: 100%; ≥40 years: 86%). Over half (8/15; 53%) of the participants were comfortable receiving a text message stating that their Pap test results were abnormal, although many preferred to receive such information via a phone call (6/15; 40%). Most participants (9/15; 60%) believed that receiving a text reminder would make them more likely to attend their appointment. The preferred method for receiving a reminder appeared to vary by age, with older women preferring telephone reminders over text messaging reminders. Analysis of open-ended questions suggested that text messaging appeals to some women due to its wide use and convenience for communicating with HCPs. However, women cited concerns about the confidentiality of messages and barriers to understanding the messages, including the physical capacity to read and accurately interpret the content of the messaging. Conclusions: Most participants indicated a willingness to receive text messages from their HCPs about cervical cancer screening results and believed that text messages were the best way to remind them of appointments for follow-up care. Potential concerns could be addressed by excluding explicit references to the nature of the appointment in the text message in order to avoid disclosure of sensitive health information to unauthorized individuals. Although text messaging seems promising to improve adherence to timely follow-up, personal preferences should be considered by allowing patients to opt-out of text communications

    Comparison of urine specimen collection times and testing fractions for the detection of high-risk human papillomavirus and high-grade cervical precancer

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    Background: Urine testing for high-risk human papillomavirus (HR-HPV) detection could provide a non-invasive, simple method for cervical cancer screening. Objectives: We examined whether HR-HPV detection is affected by urine collection time, portion of urine stream, or urine fraction tested, and assessed the performance of HR-HPV testing in urine for detection of cervical intraepithelial neoplasia grade II or worse (CIN2+). Study design: A total of 37 female colposcopy clinic attendees, ≥30 years, provided three urine samples: "first void" urine collected at home, and "initial stream" and "mid-stream" urine samples collected at the clinic later in the day. Self- and physician-collected brush specimens were obtained at the same clinic visit. Colposcopy was performed and directed biopsies obtained if clinically indicated. For each urine sample, HR-HPV DNA testing was conducted for unfractionated, pellet, and supernatant fractions using the Trovagene test. HR-HPV mRNA testing was performed on brush specimens using the Aptima HPV assay. Results: HR-HPV prevalence was similar in unfractionated and pellet fractions of all urine samples. For supernatant urine fractions, HR-HPV prevalence appeared lower in mid-stream urine (56.8%[40.8-72.7%]) than in initial stream urine (75.7%[61.9-89.5%]). Sensitivity of CIN2+ detection was identical for initial stream urine and physician-collected cervical specimen (89.9%[95%CI. =. 62.7-99.6%]), and similar to self-collected vaginal specimen (79.1%[48.1-96.6%]). Conclusion: This is among the first studies to compare methodologies for collection and processing of urine for HR-HPV detection. HR-HPV prevalence was similar in first void and initial stream urine, and was highly sensitive for CIN2+ detection. Additional research in a larger and general screening population is needed

    Impact of human papillomavirus (HPV) self-collection on subsequent cervical cancer screening completion among under-screened US women: MyBodyMyTest-3 protocol for a randomized controlled trial

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    Background: Screening substantially reduces cervical cancer incidence and mortality. More than half of invasive cervical cancers are attributable to infrequent screening or not screening at all. The current study, My Body My Test (MBMT), evaluates the impact of mailed kits for self-collection of samples for human papillomavirus (HPV) testing on completion of cervical cancer screening in low-income, North Carolina women overdue for cervical cancer screening. Methods/design: The study will enroll at least 510 US women aged 25-64 years who report no Pap test in the last 4 years and no HPV test in the last 6 years. We will randomize participants to an intervention or control arm. The intervention arm will receive kits to self-collect a sample at home and mail it for HPV testing. In both the intervention and control arms, participants will receive assistance in scheduling an appointment for screening in clinic. Study staff will deliver HPV self-collection results by phone and assist in scheduling participants for screening in clinic. The primary outcome is completion of cervical cancer screening. Specifically, completion of screening will be defined as screening in clinic or receipt of negative HPV self-collection results. Women with HPV-negative self-collection results will be considered screening-complete. All other participants will be considered screening-complete if they obtain co-testing or Pap test screening at a study-affiliated institution or other clinic. We will assess whether the self-collection intervention influences participants' perceived risk of cervical cancer and whether perceived risk mediates the relationship between HPV self-collection results and subsequent screening in clinic. We also will estimate the incremental cost per woman screened of offering at-home HPV self-collection kits with scheduling assistance as compared to offering scheduling assistance alone. Discussion: If mailed self-collection of samples for HPV testing is an effective strategy for increasing cervical cancer screening among women overdue for screening, this method has the potential to reduce cervical cancer incidence and mortality in medically underserved women at higher risk of developing cervical cancer. Trial registration: ClinicalTrials.gov NCT02651883, Registered on 11 January 2016

    Acceptability and Feasibility of Community-Based, Lay Navigator-Facilitated At-Home Self-Collection for Human Papillomavirus Testing in Underscreened Women

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    Objective: Women without regular health care providers or a medical home routinely fail to complete recommended cervical cancer screening. At-home self-collection of samples to test for high-risk strains of human papillomavirus (hrHPV) can improve screening rates. This study documents acceptability and feasibility of community lay navigator (LN)-facilitated at-home self-collection for underscreened women in Appalachian Virginia. Materials and Methods: This study used mixed methods in three phases. Phase I involved focus groups of LNs to ensure cultural acceptability of self-collection, and to enhance recruitment of medically underserved women. An environmental scan of community resources and climate was created in Phase II. During Phase III, underscreened women in Appalachian Virginia (the far southwest corner of Virginia) were recruited to complete hrHPV testing using LN-provided self-collection kits. Results: LN-facilitated at-home self-collection for HPV testing was deemed culturally acceptable and feasible to participants in this community-based pilot study. Self-kit training included 64 LNs, of which 35 engaged in the study and were provided 77 kits and instructions. A total of 59 self-kits were returned, of which 42 were correctly completed with valid HPV results, yielding a 16.6% hrHPV rate. Conclusions: Over a quarter of the women LNs recruited had no medical home, indicating this delivery model may have potential to reach women at increased risk of being underscreened for cervical cancer. Research is needed to identify optimal approaches to increase LN participation in outreach self-collection interventions

    Predictors of Cervical Cancer Screening among Infrequently Screened Women Completing Human Papillomavirus Self-Collection: My Body My Test-1

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    Background: Approximately one-half of cervical cancer cases in the United States occur in underscreened or never-screened women. We examined predictors to completing Papanicolaou (Pap) testing and whether a positive human papillomavirus (HPV) self-collection result affects Pap testing adherence among underscreened women. Materials and Methods: Low-income women aged 30-65 years who reported no Pap testing in ≥4 years were recruited in North Carolina. Knowledge, attitudes, and barriers regarding cervical cancer and Pap testing were assessed by telephone questionnaires. We mailed self-collection kits for HPV testing and provided information regarding where to obtain affordable Pap testing. Participants received $45 for completing all activities. We used multivariable logistic regression to assess the predictors of longer reported time since last Pap (≥10 vs. 4-9 years) and of completion of Pap testing following study enrollment (follow-up Pap). Results: Participants (n = 230) were primarily black (55%), uninsured (64%), and with ≤high school education (59%). Cost and finding an affordable clinic were the most commonly reported barriers to screening. White women and those with ≤high school education reported longer intervals since last Pap test. Half of the participants reported completing a follow-up Pap test (55%). Women with a positive HPV self-collection were five times more likely to report completing a follow-up Pap test than those with negative self-collection (odds ratio = 5.1, 95% confidence interval 1.4-25.7). Conclusions: Improving awareness of resources for affordable screening could increase cervical cancer screening in underserved women. Home-based HPV self-collection represents an opportunity to re-engage infrequently screened women into preventive screening services

    Acceptability and ease of use of mailed HPV self-collection among infrequently screened women in North Carolina

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    Objectives: Self-collection of cervico-vaginal samples for human papillomavirus (HPV) testing has the potential to make cervical cancer screening more accessible to underscreened women. We evaluated the acceptability and ease of use of home-based HPV self-collection within a diverse population of low-income, infrequently screened women. Methods: Participants were low-income women from North Carolina who had not received Pap testing in 4 or more years. Eligible women received a self-collection kit containing instructions and a brush for home-based sample collection. A total of 227 women returned a self-collected sample by mail and completed a questionnaire to assess their experiences with HPV self-collection. We described acceptability measures and used logistic regression to identify predictors of overall positive thoughts about the self-collection experience. Results: Nearly all women were willing to perform HPV self-collection again (98%) and were comfortable receiving the self-collection kit in the mail (99%). Overall, 81% of participants reported positive thoughts about home-based self-collection. Women with at least some college education and those who were divorced, separated or widowed were more likely to report overall positive thoughts. Aspects of self-collection that participants most commonly reported liking included convenience (53%), ease of use (32%) and privacy (23%). The most frequently reported difficulties included uncertainty that the self-collection was done correctly (16%) and difficulty inserting the self-collection brush (16%). Conclusions: Home-based self-collection for HPV was a highly acceptable screening method among low-income, underscreened women and holds the promise to increase access to cervical cancer screening in this high-risk population

    Analytical characterization of the aroma of Tinta Negra Mole red wine: Identification of the main odorants compounds

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    A method for the simultaneous determination of major and minor volatiles composition in different types (dry, medium dry, sweet and medium sweet) of a young Tinta Negra Mole (TNM) monovarietal red wine from 2003 harvest has been validated. Wine samples preparation includes a dichloromethane liquid–liquid extraction followed by concentration under a nitrogen atmosphere. The extracted fraction was analysed by gas chromatography–mass spectrometry and give quantitative information for more than 86 analytes whose concentration range from few μg l−1 to 259.1 mg l−1. The method enables high recovery of volatile compounds in wine good linearity with (r2) values higher than 0.980 and good sensitivity. The limits of detection range from 0.003 to 0.534 mg l−1 and limits of quantification from 0.009 to 1.170 mg l−1. The method allows satisfactory determination of more than 80 compounds in the TNM red wines. These wines are characterized by a high content of higher alcohols, ethyl esters, fatty acids and lactones. The levels of sulphur compounds in Tinta Negra Mole medium sweet wines are very low, but they have the highest concentration of carbonyl compounds. Quantitative analysis of the main odorants followed by the determination of aroma index allow us elucidate the aroma of these varieties. On the basis of their odour description and odour threshold, the most powerful odorants of Tinta Negra Mole wines were tentatively established
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