Hyperpolarized129 Xe NMR can detect the presence of specific lowconcentration biomolecular analytes by means of the xenon biosensor, which consists of a water-soluble, targeted cryptophane-A cage that encapsulates xenon. In this work we use the prototypical biotinylated xenon biosensor to determine the relationship between the molecular composition of the xenon biosensor and the characteristics of protein-bound resonances.The effects of diastereomer overlap, dipole-dipole coupling, chemical shift anisotropy, xenon exchange, and biosensor conformational exchange on protein-bound biosensor signal were assessed. It was found that optimal protein-bound biosensor signal can be obtained by minimizing the number of biosensor diastereomers and using a flexible linker of appropriate length.Both the linewidth and sensitivity of chemical shift to protein binding of the xenon biosensor were found to be inversely proportional to linker length.

Objective To estimate how well a convenience sample of women from the general population could self-screen for contraindications to combined oral contraceptives using a medical checklist. Methods Women 18-49 years old (N=1,271) were recruited at two shopping malls and a flea market in El Paso, Texas, and asked first whether they thought pills were medically safe for them. They then used a checklist to determine the presence of level 3 or 4 contraindications to combined oral contraceptives according to the World Health Organization Medical Eligibility Criteria. Women were then interviewed by a blinded nurse practitioner who also measured blood pressure. Results The sensitivity of the unaided self-screen to detect true contraindications was 56.2% (95% CI: 51.7%-60.6%) and specificity 57.6% (54.0%-61.1%). The sensitivity of the checklist to detect true contraindications was 83.2% (79.5%-86.3%) and specificity 88.8% (86.3%- 90.9%). Using the checklist, 6.6% (5.2%-8.0%) of women incorrectly thought they were eligible for use when, in fact, they were contraindicated, largely due to unrecognized hypertension. Seven percent (5.4%-8.2%) of women incorrectly thought they were contraindicated when they truly were not, primarily due to misclassification of migraine headaches. In regression analysis, younger women, more educated women and Spanish-speakers were significantly more likely to correctly self-screen (p<0.05). Conclusion Self-screening for contraindications to oral contraceptives using a medical checklist is relatively accurate. Unaided screening is inaccurate and reflects common misperceptions about the safety of oral contraceptives. Over-the-counter provision of this method would likely be safe, especially for younger women and if independent blood pressure screening were encouraged.

A time-of-flight imaging technique is introduced to visualize fluid flow and dispersion through porous media using NMR. As the fluid flows through a sample, the nuclear spin magnetization is modulated by RF pulses and magnetic field gradients to encode the spatial coordinates of the fluid. When the fluid leaves the sample, its magnetization is recorded by a second RF coil. This scheme not only facilitates a time-dependent imaging of fluid flow, it also allows a separate optimization of encoding and detection subsystems to enhance overall sensitivity. The technique is demonstrated by imaging gas flow through a porous rock.

ObjectiveTo examine the effectiveness, safety, and acceptability of nurse provision of early medical abortion compared to physicians at three facilities in Mexico City.MethodsWe conducted a randomized non-inferiority trial on the provision of medical abortion and contraceptive counselling by physicians or nurses. The participants were pregnant women seeking abortion at a gestational duration of 70 days or less. The medical abortion regimen was 200 mg of oral mifepristone taken on-site followed by 800 μg of misoprostol self–administered buccally at home 24 hours later. Women were instructed to return to the clinic for follow-up 7–15 days later. We did an intention-to-treat analysis for risk differences between physicians’ and nurses’ provision for completion and the need for surgical intervention.FindingsOf 1017 eligible women, 884 women were included in the intention-to-treat analysis, 450 in the physician-provision arm and 434 in the nurse-provision arm. Women who completed medical abortion, without the need for surgical intervention, were 98.4% (443/450) for physicians’ provision and 97.9% (425/434) for nurses’ provision. The risk difference between the group was 0.5% (95% confidence interval, CI: −1.2% to 2.3%). There were no differences between providers for examined gestational duration or women’s contraceptive method uptake. Both types of providers were rated by the women as highly acceptable.ConclusionNurses’ provision of medical abortion is as safe, acceptable and effective as provision by physicians in this setting. Authorizing nurses to provide medical abortion can help to meet the demand for safe abortion services.

Maternal mortality among indigenous women in Guatemala is high. To reduce deaths during transport from far-away rural communities to the hospital, maternity waiting homes (MWH) were established near to hospitals where women with high-risk pregnancies await their delivery before being transferred for labour to the hospital. However, the homes are under-utilised. We conducted a qualitative study with 48 stakeholders (MWH users, family members, community leaders, MWH staff, Mayan midwives and health centre and hospital medical staff) in Huehuetenango and Cuilco to identify barriers before, during and after the women's stay in the homes. The women most in need - indigenous women from remote areas - seemed to have least access to the MWHs. Service users' lack of knowledge about the existence of the homes, limited provision of culturally appropriate care and a lack of sustainable funding were the most important problems identified. While the strategy of MWHs has the potential to contribute to the prevention of maternal (as well as newborn) deaths in rural Guatemala, they can only function effectively if they are planned and implemented with community involvement and support, through a participatory approach.

Social manifestations of abortion stigma depend upon cultural, legal, and religious context. Abortion stigma in Mexico is under-researched. This study explored the sources, experiences, and consequences of stigma from the perspectives of women who had had an abortion, male partners, and members of the general population in different regional and legal contexts. We explored abortion stigma in Mexico City where abortion is legal in the first trimester and five states-Chihuahua, Chiapas, Jalisco, Oaxaca, and Yucatán-where abortion remains restricted. In each state, we conducted three focus groups-men ages 24-40 years (n = 36), women 25-40 years (n = 37), and young women ages 18-24 years (n = 27)-and four in-depth face-to-face interviews in total; two with women (n = 12) and two with the male partners of women who had had an abortion (n = 12). For 4 of the 12 women, this was their second abortion. This exploratory study suggests that abortion stigma was influenced by norms that placed a high value on motherhood and a conservative Catholic discourse. Some participants in this study described abortion as an "indelible mark" on a woman's identity and "divine punishment" as a consequence. Perspectives encountered in Mexico City often differed from the conservative postures in the states.

study in Mexico that it is often sold on a pill by pill basis, which may explain the drop in sales. 22 The present study provides new national and regional estimates for 2006. It uses the same methodology as the 1990 study, but adapts those methods when necessarymost importantly by incorporating the use of misoprostol to induce abortion, a practice that was rare in the earlier survey period. This approach provides for comparability, and enables us to assess trends in induced abortion in Mexico over the past decade and a half. In addition to looking at changes in abortion incidence between 1990 and 2006, we examine patterns in hospitalization due to abortion-related complications, a key indicator of morbidity resulting from unsafe abortion. Finally, we explore the relationship between contraceptive use and differences in abortion incidence among the four regions and at the national level, and discuss the broader relevance and implications of our findings. DATA AND METHODS Data SourcesWe used two data sources for estimating abortion incidence: hospital discharge data on the number of women treated for abortion complications in 2006, and a survey of key informants who were knowledgeable about abortion provision in Mexico to obtain an estimate of the proportion of women who get abortions who are hospitalized.•Hospital discharge data. Data from Mexico's National System of Health Information (Sistema Nacional de Información en Salud) on the number of women treated in publicsector hospitals for abortion complications in 2006 were aggregated for seven hospital systems (see Web site Appendix at http://www.guttmacher.org/pubs/ifpp/appendix/ 3404.pdf). 27 We examined the data for quality and completeness and to ensure comparability with data for 1990. To obtain a count of patients treated for postabortion complications in 2006 that was comparable to the count used in 1990, we selected the appropriate diagnostic codes from the new ICD-10 classification system that matched those from the earlier ICD-9 system. The previous study had made other adjustments to the hospital discharge data to account for misclassification of codes; 16 because the 2006 data are of higher quality, these adjustments were not necessary.The sources of health systems data on hospital care changed between 1990 and 2006: In 2006, the number of women hospitalized for abortion complications was obtained from three sources (outpatient, inpatient and emergency cases), whereas a single source was used in 1990 (only inpatient cases were available at that time). The total number of women treated for abortion complications (resulting from spontaneous or induced abortion) in all components of the public-sector hospital system in 2006 was 194,774 (112,978 reported inpatients, 26,823 reported outpatients and 54,973 estimated emergency cases; see Appendix Table 1).•Health Professionals Survey. The Health Professionals Survey (HPS) was designed to assess the conditions of induced abortions; given the rise in use of contraceptives since the 1980s and the increase ...

Laser-enhanced (LE) 129Xe nuclear magnetic resonance (NMR) is an exceptional tool for sensing extremely small physical and chemical changes; however, the difficult mechanics of bringing polarized xenon and samples of interest together have limited applications, particularly to biological molecules. Here we present a method for accomplishing solution 129Xe biosensing based on flow (bubbling) of LE 129Xe gas through a solution in situ in the NMR probe, with pauses for data acquisition. This overcomes fundamental limitations of conventional solution-state LE 129Xe NMR, e.g., the difficulty in transferring hydrophobic xenon into aqueous environments, and the need to handle the sample to refresh LE 129Xe after an observation pulse depletes polarization. With this new method, we gained a factor of >100 in sensitivity due to improved xenon transfer to the solution and the ability to signal average by renewing the polarized xenon. Polarized xenon in biosensors was detected at very low concentrations,