Role of Secondary Organic Matter on Soot Particle Toxicity in Reconstituted Human Bronchial Epithelia Exposed at the Air-Liquid Interface

Secondary organic matter (SOM) formed from gaseous precursors constitutes a major mass fraction of fine particulate matter. However, there is only limited evidence on its toxicological impact. In this study, air-liquid interface cultures of human bronchial epithelia were exposed to different series of fresh and aged soot particles generated by a miniCAST burner combined with a micro smog chamber (MSC). Soot cores with geometric mean mobility diameters of 30 and 90 nm were coated with increasing amounts of SOM, generated from the photo-oxidation of mesitylene and ozonolysis of α-pinene. At 24 h after exposure, the release of lactate dehydrogenase (LDH), indicating cell membrane damage, was measured and proteome analysis, i.e. the release of 102 cytokines and chemokines to assess the inflammatory response, was performed. The data indicate that the presence of the SOM coating and its bioavailability play an important role in cytotoxicity. In particular, LDH release increased with increasing SOM mass/total particle mass ratio, but only when SOM had condensed on the outer surface of the soot cores. Proteome analysis provided further evidence for substantial interference of coated particles with essential properties of the respiratory epithelium as a barrier as well as affecting cell remodeling and inflammatory activity.

Characterizing the Particle Composition and Cloud Condensation Nuclei from Shipping Emission in Western Europe

Commercial shipping is considered as an important source of air pollution and cloud condensation nuclei (CCN). To assess the climatic and environmental impacts of shipping, detailed characterization of ship plumes near the point of emission and understanding of ship plume evolution further downwind are essential. This airborne measurement study presents the online characterization of particulate phase ship emissions in the region of Western Europe in 2019 prior to new international sulfur emission controls becoming enacted. More than 30 ships from both the sulfur emission control area (SECA) in the English Channel and the open sea (OS) are measured and compared. Ships within the SECA emitted much less sulfate (SO₄) compared with those at OS. When shifted to a lower apparent fuel sulfur content (FSC) at similar engine loads, the peak of the fresh ship emitting the particle number size distribution shifted from around 60-80 nm in diameter to below 40 nm in diameter. The emission factors (EFs) of sulfate are predicted to decrease by around 94% after the 2020 regulation on ship sulfur emission in the open ocean. The EFs of refractory black carbon (rBC) and organic compounds (Org) do not appear to be directly affected by the lower sulfur contents. The total number concentration for condensation nuclei (CN) >2.5 nm and >0.1 μm are predicated to be reduced by 69 and 56%, respectively. Measured plume evolution results indicate that the S(IV) to S(VI) conversion rate was around 23.4% per hour at the beginning of plume evolution, and the CCN and CN >2.5 nm ratio increased with plume age primarily due to condensation and coagulation. We estimate that the new sulfur emission regulation will lead to a reduction of more than 80% in CCN from fresh ship emissions. The ship-emitted EFs results presented here will also inform emission inventories, policymaking, climate, and human health studies.

Mixing State of Carbonaceous Aerosols of Primary Emissions from "Improved" African Cookstoves

Designs of "improved" stoves are introduced recently to benefit the solid fuel consumption of cooking activities in developing countries, but the uncertainties concerning the combustion processes and particulate emissions remain poorly characterized. To help understand this, combustion in three examples of "improved" African cookstoves was investigated in the laboratory. A typical European heating stove was included for comparison purpose. Detailed aerosol emissions were studied in real-time with an Aerosol Mass Spectrometer and Single Particle Soot Photometer, to explore interactions between black carbon (BC) and organic carbon aerosols, which were parametrized according to modified combustion efficiency (MCE), a common metric used within the atmospheric emission community. Greater than 50% of the total organic matter (OM) was found in BC-containing particles when MCE was >0.95 for dry oak and coal fuels, whereas at lower MCE, over 80% of the total OM for most of the fuels existed in particles without detectable BC. When the OM mass fraction of total particulate matter (PM₁) > 0.9, the mass ratio of OM to refractory BC in BC-containing particles was about 2-3, but only ∼0.8 when OM mass fraction <0.9. These findings are not currently included in models and such information should be considered in the future emission scenarios.

Light Absorption Enhancement of Black Carbon Aerosol Constrained by Particle Morphology

The radiative forcing of black carbon aerosol (BC) is one of the largest sources of uncertainty in climate change assessments. Contrasting results of BC absorption enhancement ( E_abs) after aging are estimated by field measurements and modeling studies, causing ambiguous parametrizations of BC solar absorption in climate models. Here we quantify E_abs using a theoretical model parametrized by the complex particle morphology of BC in different aging scales. We show that E_abs continuously increases with aging and stabilizes with a maximum of ∼3.5, suggesting that previous seemingly contrast results of E_abs can be explicitly described by BC aging with corresponding particle morphology. We also report that current climate models using Mie Core-Shell model may overestimate E_abs at a certain aging stage with a rapid rise of E_abs, which is commonly observed in the ambient. A correction coefficient for this overestimation is suggested to improve model predictions of BC climate impact.

Online Chemical Characterization of Food-Cooking Organic Aerosols: Implications for Source Apportionment

Food-cooking organic aerosols (COA) are one of the primary sources of submicron particulate matter in urban environments. However, there are still many questions surrounding source apportionment related to instrumentation as well as semivolatile partitioning because COA evolve rapidly in the ambient air, making source apportionment more complex. Online measurements of emissions from cooking different types of food were performed in a laboratory to characterize particles and gases. Aerosol mass spectrometer (AMS) measurements showed that the relative ionization efficiency for OA was higher (1.56-3.06) relative to a typical value of 1.4, concluding that AMS is over-estimating COA and suggesting that previous studies likely over-estimated COA concentrations. Food-cooking mass spectra were generated using AMS, and gas and particle food markers were identified with filter inlets for gases and aerosols-chemical ionization mass spectrometer (CIMS) measurements to be used in future food cooking-source apportionment studies. However, there is a considerable variability in both gas and particle markers, and dilution plays an important role in the particle mass budget, showing the importance of using these markers with caution during receptor modeling. These findings can be used to better understand the chemical composition of COA, and they provides useful information to be used in future source-apportionment studies.

Novel insights on new particle formation derived from a pan-european observing system

The formation of new atmospheric particles involves an initial step forming stable clusters less than a nanometre in size (<~1 nm), followed by growth into quasi-stable aerosol particles a few nanometres (~1–10 nm) and larger (>~10 nm). Although at times, the same species can be responsible for both processes, it is thought that more generally each step comprises differing chemical contributors. Here, we present a novel analysis of measurements from a unique multi-station ground-based observing system which reveals new insights into continental-scale patterns associated with new particle formation. Statistical cluster analysis of this unique 2-year multi-station dataset comprising size distribution and chemical composition reveals that across Europe, there are different major seasonal trends depending on geographical location, concomitant with diversity in nucleating species while it seems that the growth phase is dominated by organic aerosol formation. The diversity and seasonality of these events requires an advanced observing system to elucidate the key processes and species driving particle formation, along with detecting continental scale changes in aerosol formation into the future.

Enhanced light absorption by mixed source black and brown carbon particles in UK winter

Black carbon (BC) and light-absorbing organic carbon (brown carbon, BrC) play key roles in warming the atmosphere, but the magnitude of their effects remains highly uncertain. Theoretical modelling and laboratory experiments demonstrate that coatings on BC can enhance BC's light absorption, therefore many climate models simply assume enhanced BC absorption by a factor of ∼1.5. However, recent field observations show negligible absorption enhancement, implying models may overestimate BC's warming. Here we report direct evidence of substantial field-measured BC absorption enhancement, with the magnitude strongly depending on BC coating amount. Increases in BC coating result from a combination of changing sources and photochemical aging processes. When the influence of BrC is accounted for, observationally constrained model calculations of the BC absorption enhancement can be reconciled with the observations. We conclude that the influence of coatings on BC absorption should be treated as a source and regionally specific parameter in climate models.

Physical and chemical processes of air masses in the Aegean Sea during Etesians: Aegean-GAME airborne campaign

High-resolution measurements of gas and aerosols' chemical composition along with meteorological and turbulence parameters were performed over the Aegean Sea (AS) during an Etesian outbreak in the framework of the Aegean-GAME airborne campaign. This study focuses on two distinct Etesian patterns, with similarities inside the Marine Atmospheric Boundary Layer (MABL) and differences at higher levels. Under long-range transport and subsidence the pollution load is enhanced (by 17% for CO, 11% for O3, 28% for sulfate, 62% for organic mass, 47% for elemental carbon), compared to the pattern with a weaker synoptic system. Sea surface temperature (SST) was a critical parameter for the MABL structure, turbulent fluxes and pollutants' distribution at lower levels. The MABL height was below 500 m asl over the eastern AS (favoring higher accumulation), and deeper over the western AS. The most abundant components of total PM1 were sulfate (40-50%) and organics (30-45%). Higher average concentrations measured over the eastern AS (131 ± 76 ppbv for CO, 62.5 ± 4.1 ppbv for O3, 5.0 ± 1.1 μg m(-3) for sulfate, 4.7 ± 0.9 μg m(-3) for organic mass and 0.5 ± 0.2 μg m(-3) for elemental carbon). Under the weaker synoptic system, cleaner but more acidic air masses prevailed over the eastern part, while distinct aerosol layers of different signature were observed over the western part. The Aitken and accumulation modes contributed equally during the long-range transport, while the Aitken modes dominated during local or medium range transport.

Contribution of nitrated phenols to wood burning brown carbon light absorption in Detling, United Kingdom during winter time

We show for the first time quantitative online measurements of five nitrated phenol (NP) compounds in ambient air (nitrophenol C6H5NO3, methylnitrophenol C7H7NO3, nitrocatechol C6H5NO4, methylnitrocatechol C7H7NO4, and dinitrophenol C6H4N2O5) measured with a micro-orifice volatilization impactor (MOVI) high-resolution chemical ionization mass spectrometer in Detling, United Kingdom during January-February, 2012. NPs absorb radiation in the near-ultraviolet (UV) range of the electromagnetic spectrum and thus are potential components of poorly characterized light-absorbing organic matter ("brown carbon") which can affect the climate and air quality. Total NP concentrations varied between less than 1 and 98 ng m(-3), with a mean value of 20 ng m(-3). We conclude that NPs measured in Detling have a significant contribution from biomass burning with an estimated emission factor of 0.2 ng (ppb CO)(-1). Particle light absorption measurements by a seven-wavelength aethalometer in the near-UV (370 nm) and literature values of molecular absorption cross sections are used to estimate the contribution of NP to wood burning brown carbon UV light absorption. We show that these five NPs are potentially important contributors to absorption at 370 nm measured by an aethalometer and account for 4 ± 2% of UV light absorption by brown carbon. They can thus affect atmospheric radiative transfer and photochemistry and with that climate and air quality.

Characterizing the aging of biomass burning organic aerosol by use of mixing ratios: a meta-analysis of four regions

Characteristic organic aerosol (OA) emission ratios (ERs) and normalized excess mixing ratios (NEMRs) for biomass burning (BB) events have been calculated from ambient measurements recorded during four field campaigns. Normalized OA mass concentrations measured using Aerodyne Research Inc. quadrupole aerosol mass spectrometers (Q-AMS) reveal a systematic variation in average values between different geographical regions. For each region, a consistent, characteristic ratio is seemingly established when measurements are collated from plumes of all ages and origins. However, there is evidence of strong regional and local-scale variability between separate measurement periods throughout the tropical, subtropical, and boreal environments studied. ERs close to source typically exceed NEMRs in the far-field, despite apparent compositional change and increasing oxidation with age. The absence of any significant downwind mass enhancement suggests no regional net source of secondary organic aerosol (SOA) from atmospheric aging of BB sources, in contrast with the substantial levels of net SOA formation associated with urban sources. A consistent trend of moderately reduced ΔOA/ΔCO ratios with aging indicates a small net loss of OA, likely as a result of the evaporation of organic material from initial fire emissions. Variability in ERs close to source is shown to substantially exceed the magnitude of any changes between fresh and aged OA, emphasizing the importance of fuel and combustion conditions in determining OA loadings from biomass burning.

Impact of alternative fuels on emissions characteristics of a gas turbine engine - part 2: volatile and semivolatile particulate matter emissions

The work characterizes the changes in volatile and semivolatile PM emissions from a gas turbine engine resulting from burning alternative fuels, specifically gas-to-liquid (GTL), coal-to-liquid (CTL), a blend of Jet A-1 and GTL, biodiesel, and diesel, to the standard Jet A-1. The data presented here, compares the mass spectral fingerprints of the different fuels as measured by the Aerodyne high resolution time-of-flight aerosol mass spectrometer. There were three sample points, two at the exhaust exit plane with dilution added at different locations and another probe located 10 m downstream. For emissions measured at the downstream probe when the engine was operating at high power, all fuels produced chemically similar organic PM, dominated by C(x)H(y) fragments, suggesting the presence of long chain alkanes. The second largest contribution came from C(x)H(y)O(z) fragments, possibly from carbonyls or alcohols. For the nondiesel fuels, the highest loadings of organic PM were from the downstream probe at high power. Conversely, the diesel based fuels produced more organic material at low power from one of the exit plane probes. Differences in the composition of the PM for certain fuels were observed as the engine power decreased to idle and the measurements were made closer to the exit plane.

Chemical and microphysical characterization of ambient aerosols with the aerodyne aerosol mass spectrometer

The application of mass spectrometric techniques to the real-time measurement and characterization of aerosols represents a significant advance in the field of atmospheric science. This review focuses on the aerosol mass spectrometer (AMS), an instrument designed and developed at Aerodyne Research, Inc. (ARI) that is the most widely used thermal vaporization AMS. The AMS uses aerodynamic lens inlet technology together with thermal vaporization and electron-impact mass spectrometry to measure the real-time non-refractory (NR) chemical speciation and mass loading as a function of particle size of fine aerosol particles with aerodynamic diameters between approximately 50 and 1,000 nm. The original AMS utilizes a quadrupole mass spectrometer (Q) with electron impact (EI) ionization and produces ensemble average data of particle properties. Later versions employ time-of-flight (ToF) mass spectrometers and can produce full mass spectral data for single particles. This manuscript presents a detailed discussion of the strengths and limitations of the AMS measurement approach and reviews how the measurements are used to characterize particle properties. Results from selected laboratory experiments and field measurement campaigns are also presented to highlight the different applications of this instrument. Recent instrumental developments, such as the incorporation of softer ionization techniques (vacuum ultraviolet (VUV) photo-ionization, Li+ ion, and electron attachment) and high-resolution ToF mass spectrometers, that yield more detailed information about the organic aerosol component are also described.

Deconvolution and quantification of hydrocarbon-like and oxygenated organic aerosols based on aerosol mass spectrometry

A new technique has been developed to deconvolve and quantify the mass concentrations of hydrocarbon-like and oxygenated organic aerosols (HOA and OOA) using highly time-resolved organic mass spectra obtained with an Aerodyne Aerosol Mass Spectrometer (AMS). This technique involves a series of multivariate linear regressions that use mass-to-charge ratios (ml/s) 57 (mostly C4H9+) and 44 (mostly CO2+)-the identified AMS mass spectral tracers for HOA and OOA, respectively-as the initial principal components. Two algorithms have been developed: algorithm 1 is based solely on m/z 44 and m/z 57, and algorithm 2 is an iterative procedure expanded from algorithm 1. This technique was applied to the AMS organic aerosol data acquired at the EPA Pittsburgh Supersite during September 2002. The reconstructed organic concentrations (= HOA + OOA) agree well with the measured values (r2 = 0.997, slope = 0.998), and the reconstructed organic data matrix (size = 3199 time steps x 300 m/z's) explains 99% of the variance in the measured time series. In addition, the extracted mass spectrum of HOA shows high similarity to those of diesel exhaust, lubricating oil, and freshly emitted traffic aerosols observed in urban areas, while the spectrum of OOA closely resembles those of aged organic aerosols sampled in rural areas and also shows similarity with the spectrum of fulvic acid- a humic-like substance that is ubiquitous in the environment and has previously been used as an analogue to represent polyacid components found in highly processed and oxidized atmospheric organic aerosols. There is evidence for the presence of a third component, although its contribution to the total organic signal appears to be small in this study. The most important result is that m/z 44 and m/z 57 are reliable AMS mass spectral "markers" that provide the "first guess" for algorithm 2 which allows the quantitative description of the organic aerosol concentration and mass spectra over a period of 16 days in a major urban area and allows the extraction of mass spectra of OOA and HOA that can be interpreted chemically. These findings indicate the potential of performing organic source apportionment on the basis of total particle mass, rather than on the basis of organic tracer compounds that contribute a small fraction of this mass.

Street canyon aerosol pollutant transport measurements

Current understanding of dispersion in street canyons is largely derived from relatively simple dispersion models. Such models are increasingly used in planning and regulation capacities but are based upon a limited understanding of the transport of substances within a real canyon. In recent years, some efforts have been made to numerically model localised flow in idealised canyons (e.g., J. Appl. Meteorol. 38 (1999) 1576-89) and stepped canyons (Assimakopoulos V. Numerical modelling of dispersion of atmospheric pollution in and above urban canopies. PhD thesis, Imperial College, London, 2001) but field studies in real canyons are rare. To further such an understanding, a measurement campaign has been conducted in an asymmetric street canyon with busy one-way traffic in central Manchester in northern England. The eddy correlation method was used to determine fluxes of size-segregated accumulation mode aerosol. Measurements of aerosol at a static location were made concurrently with measurements on a platform lift giving vertical profiles. Size-segregated measurements of ultrafine and coarse particle concentrations were also made simultaneously at various heights. In addition, a small mobile system was used to make measurements of turbulence at various pavement locations within the canyon. From this data, various features of turbulent transport and dispersion in the canyon will be presented. The concentration and the ventilation fluxes of vehicle-related aerosol pollutants from the canyon will be related to controlling factors. The results will also be compared with citywide ventilation data from a separate measurement campaign conducted above the urban canopy.

Spatial awareness in urologists: are they different?

OBJECTIVE

To compare innate spatial awareness skills, using the MIST-VR system (Ethicon Ltd, Edinburgh, a computer-based virtual reality system that objectively tests spatial awareness) among three groups of people (consultant urologists, urological trainees and controls who were not surgeons), because urological surgeons require spatial awareness for endoscopic and laparoscopic surgery, but trainees are selected by academic prowess rather than surgical aptitude.

SUBJECTS AND METHODS

The MIST-VR system was used to test 122 volunteers in three groups, i.e. 39 consultant urologists, 46 urological trainees and 37 controls (not surgeons). The demographic data recorded for each group included age, sex, eyesight, handedness, and endoscopic and laparoscopic experience. Volunteers performed a repetitive series of three tasks using the system. Their performance was measured in terms of time, errors and economy of movement, as well as the duration and accuracy of diathermy in Task 3.

RESULTS

The consultants were significantly older than the trainees and controls (both P<0.001) and had more endoscopic experience (P=0.005). In Task 1, the trainees made significantly fewer errors (P=0.045) and had a greater economy of movement (P=0.03) than the controls. In Task 2 the trainees performed the task more rapidly than the consultants (P=0.04) and controls (P=0.02). Trainees were more economical in movement than were consultants (P=0.031) and controls (P=0.046). In the more complex Task 3, trainees outperformed consultants in terms of errors (P=0.03), economy of movement (P=0.046), total diathermy time (P=0.005) and diathermy error (P=0.03). Controls performed similarly to the consultants. Although there was a trend towards better performance by trainees over controls, this was only significant for time (P=0.04) and total diathermy time (P=0.011). A few participants had results that were >2 SD above the mean and several people could not complete Task 3.

CONCLUSIONS

Urologists do not differ from the general population in terms of innate spatial ability in this setting. There are several people who may have a defect in spatial awareness but the incidence was the same in each group. Urological trainees outperformed consultants in these tasks; the reasons for this are unclear. The MIST-VR system is of no help in aptitude testing for urological trainees, although it may have a role in teaching laparoscopic surgery. Testing other psychometric components may be more important for acquiring surgical skills than innate spatial-awareness skills. Further studies are required to investigate this possibility.

Laparoscopic radical nephrectomy

Laparoscopic radical nephrectomy has gained in popularity as an accepted treatment modality for localized renal cell carcinoma at many centers worldwide. Laparoscopic radical nephrectomy may be performed via a transperitoneal or retroperitoneal approach. Mostly, the transperitoneal approach is used. Current indications for laparoscopic radical nephrectomy include patients with T(1)-T(3a)N(0)M(0) renal tumors. Herein, transperitoneal as well as retroperitoneal laparoscopic approaches are described. Surgical outcomes and complications from published series are reviewed with comparison to open surgery. Special related concerns as oncologic principles, organ retrieval, lymphadenectomy, and concomitant adrenalectomy are addressed. In conclusion, laparoscopic radical nephrectomy is now established with considerable advantages; decreased postoperative morbidity, decreased analgesic requirements, improved cosmesis, shorter hospital stay and convalescence. Although no long-term follow-up is available, short and intermediate follow-up results confirm the effectiveness of laparoscopic radical nephrectomy.

Virtual endoscopy in urology

Recent years have seen notable advances in virtual reality technology and increased interest in potential medical applications. Computed tomography and magnetic resonance imaging data sets, historically viewed as axial images, may now be used to construct a virtual reality endoscopic image, and navigator software systems allow the operator to 'fly' through the urinary tract. Technological evolution has improved the quality of reconstruction, as this is dependent on the software and data set, allowing virtual reality to begin to challenge endoscopic evaluation. This review describes the evolution of virtual reality in urology and the milestones of its current clinical use. Applications may become widespread in the diagnostic evaluation of common urological symptoms, the planning of surgery and the training of future urologists.

Weight management practices among primary care providers

This pilot study examined how primary care providers manage patients with weight problems, an important component of primary care. A convenience sample of 17 nurse practitioners and 15 physicians were surveyed about assessments and interventions used in practice for weight management along with perceived barriers to providing effective weight management. Practice patterns between gender, profession and practice setting of the nurse practitioners were compared.

Striving for quality in advanced practice nursing education

The issue of establishing and maintaining high-quality advanced practice educational programs, practice competencies, and certification criteria is currently the focus of much debate and discussion within nursing. This article focuses on the issue of accreditation for advanced practice nursing educational programs in four areas: (1) history of accreditation in nursing education; (2) accreditation of educational programs for clinical nurse specialists, nurse midwives, and nurse anesthetists; (3) accreditation of programs for nurse practitioners; and (4) current and future educational issues and challenges. To participate in shaping the changes occurring in the current health delivery system, the nursing profession and advanced practice nursing educators must present a strong, visionary, and collaborative voice concerning quality educational programs.

New directions for the study of overweight

In this issue, three authors contribute to our knowledge of triggers or cues to weight-related behavior. Two of these authors focus on the effect of emotion on eating behavior. Popkess-Vawter, Wendel, Schmoll, and O'Connell (1998, in this issue) explicate reversal theory as a way to account for feelings and stress that trigger weight cyclers to overeat. Timmerman (1998, in this issue), in a study of nonpurge binge eaters, reports the relationship between caloric intake patterns and binge eating. Both researchers have added to our knowledge about triggers to eating behavior. Finally, Brink and Ferguson (1998), in their study of male and female successful dieters, add to the limited knowledge concerning triggers to weight loss. They describe reasons for deciding to lose weight among a population of successful underweight, normal weight, and obese dieters. Three authors contribute to the new weight research thrust of prevention. Two of the authors report the results of intervention studies. Reifsnider (1998, in this issue), in the only article on children, presents a follow-up study of a family-focused, community-based nursing intervention for growth-deficient, low-income Euro-American and Mexican American preschool children. Her work is an example of the context- and lifestyle-sensitive prevention-focused studies needed in weight research. Ciliska (1998, in this issue) reports findings from a randomized trial of a psycho-educational intervention with obese healthy women aimed at increasing self-esteem and decreasing restrained eating patterns. Her work follows some new thinking in the area of weight control that recognizes the dangers of chronic dieting and proposes a focus on self-acceptance, better nutrition, regular physical activity, and the prevention of further weight gain triggered by chronic dieting (Brownell & Cohen, 1995). Walker (1998, in this issue), the third author, in a multiethnic study of new mothers, explores the concept of weight-related distress and associations of anthropometric and psychosocial variables with feelings about weight. Her work adds to our understanding about critical periods and risks for weight gain. Allan (1998, in this issue), in a study of African American, Euro-American, and Mexican American women, reports women's explanatory models of overweight and the congruence of these models with professional models and recommendations for treatment for overweight. Her research contributes needed understandings of how high-risk populations view overweight, how participants' lifestyles and situations influence their ideas about weight, and how these perspectives influence efforts to control weight. Nursing needs to continue to refine and rethink what constitutes research on weight. This special issue offers some examples of scholars attempting to trailblaze new directions in nursing weight research. One thrust has been the significant attention on weight as a focus of investigation and not just as one of several health behaviors. A second and equally compelling area of inquiry has been the explicit attention directed to studying people of color, especially women, within the social context of their lives. Because ethnicity, social status, and gender are inextricably intertwined with health, one challenge is to try to understand weight issues through an ethnic, gender, and social status lens. Researchers who embrace this paradigm refuse to look at weight as a homogeneous condition but focus their attention instead on specific subgroups in the population without making middle-class Euro-Americans the norm. The number of researchers who are examining connections between ethnicity and social status and weight is growing. The complexity of weight-health promotion requires that we not only boldly examine weight in relationship to the individual in context but also explicate the macroenvironmental influences on weight. More needs to be done to translate findings from this body of research into better models

Explanatory models of overweight among African American, Euro-American, and Mexican American women

Ethnographic interviewing methods were used to explore women's explanatory models (EMs) of overweight and the congruence of these models with professional models and professionally recommended treatments for overweight. Through community-based snowball and theoretical sampling, 40 African American, 40 Euro-American, and 40 Mexican American women of varying social status and weight participated in multiple ethnographic interviews, which were subsequently interpreted using domain analysis and constant comparison. Study participants' EMs of overweight ranged from simple to complex, were generally similar across the three study groups, and only partially congruent with professional EMs of obesity. Major differences in EMs between the study groups were found in the dimensions of etiologies and consequences of overweight. There was partial congruence between participants' EMs and professionally recommended treatments for overweight.

Exploring the use of explanatory models in nursing research and practice

PURPOSE

To address the lack of information in nursing for delivering culturally appropriate care and provide a framework for nurses to incorporate diverse beliefs and health needs into research and practice. People interpret and react to health and illness events within a cultural system. However, the nursing literature contains little about how to elicit cultural beliefs.

ORGANIZING FRAMEWORK

Use of Kleinman's (1980) concept of explanatory models (EMs) is explored first, by describing the concept as it was developed by Kleinman, and second, by illustrating how it was used in three research studies conducted between 1990 and 1994.

METHOD

Individual in-depth interviews were conducted with community-based convenience samples. Data were analyzed using content analysis. Explanatory models were explored with health people following illness, and with people having a condition with potential health risks, to illustrate their usefulness in nursing research and practice.

CONCLUSIONS

The findings provide a beginning understanding of the complex linkages between beliefs and actions and demonstrate the versatility and usefulness of EMs for nursing research and practice. Assessing models offers one means for researchers and clinicians to explore health beliefs and the linkages between beliefs and behaviors.

Weight loss methods used by African American and Euro-American women

In this naturalistic study employing intensive interviews and anthropometric measures, an educationally and economically diverse community-based sample of 40 African American and 40 Euro-American women described their lifetime experiences with weight management. Twenty types of weight loss methods were identified and grouped into one of three categories: lifestyle work, head work, and professional services. The most frequently used weight loss methods were from the lifestyle work category, with the leading methods identified as exercise on own and reduce high calorie and/or increase low calorie foods. African Americans and Euro-Americans overwhelmingly used similar weight loss methods, with the only significant difference occurring in the more frequent use of commercial diet products among the African American group. Methods from the head work category were used significantly more often by women with higher social status, while heavier women more frequently sought professional services to lose weight than thinner women. The Euro-American women engaged in weight loss methods for significantly longer periods of time and were found to weigh significantly less than the African American women. These findings suggest that the shorter duration of weight loss attempts may be a major factor contributing to the larger body size in African American women.

Combination and monotherapy with zidovudine and zalcitabine in patients with advanced HIV disease. The NIAID AIDS Clinical Trials Group

OBJECTIVE

To compare the safety and efficacy of continuing zidovudine therapy with that of zalcitabine alone or zalcitabine and zidovudine used together.

DESIGN

A randomized, double-blind, controlled trial.

SETTING

AIDS Clinical Trials units and National Hemophilia Foundation sites.

PATIENTS

1001 patients with symptomatic human immunodeficiency (HIV) disease and 300 or fewer CD4 cells/mm3 or asymptomatic HIV disease and 200 or fewer CD4 cells/mm3 who had tolerated zidovudine therapy for 6 months or more.

INTERVENTION

Patients were randomly assigned to receive zidovudine, 600 mg/d; zalcitabine, 2.25 mg/d; or zidovudine, 600 mg/d, and zalcitabine, 2.25 mg/d.

MEASUREMENTS

The primary end point was time to disease progression or death.

RESULTS

The median follow-up time was 17.7 months. The estimated 12-month event-free rates were 70%, 67%, and 73%, respectively, for the zidovudine, zalcitabine, and combination groups (P = 0.26). A trend analysis showed significantly lower progression rates for combination therapy compared with zidovudine therapy as the pretreatment CD4 cell count increased (P = 0.027). For patients with 150 or more CD4 cells/mm3, those receiving combination therapy were less likely to have disease progression or to die than were those receiving zidovudine (relative risk, 0.51; 95% CI, 0.28 to 0.93; P = 0.029). We observed no difference between the zalcitabine and zidovudine groups (relative risk, 0.74; CI, 0.40 to 1.36; P = 0.33). For patients with 50 to 150 CD4 cells/mm3 or fewer than 50 CD4 cells/mm3, we found no differences among the treatment groups (P = 0.69 and P = 0.57, respectively). Severe toxic effects occurred less frequently among patients with 150 or more CD4 cells/mm3.

CONCLUSIONS

We found no overall benefits of zalcitabine used alone or with zidovudine. However, a trend analysis suggested a better outcome for combination therapy compared with zidovudine as the pretreatment CD4 cell count increased.

A biomedical and feminist perspective on women's experiences with weight management

Weight concerns and dieting have become so normative for U.S. women that weight is the lens through which experience is viewed. The obsession with weight and dieting among women is considered by feminists to be one result of the oppression by women resulting from questionable weight standards and weight control programs that foster a view of overweight as a sign of addiction and lack of control. Feminist critique is used to deconstruct both the literature related to weight standards and health and the research on weight loss/weight management. Feminist and ethnographic methods are used to describe successful and unsuccessful experiences with weight management of 20 Euro-American women who had participated in a 1985 weight study and agreed to be reinterviewed. Success at weight management was examined from a biomedical perspective using Body Mass Index (BMI) norms and from a feminist perspective using participants' subjective definitions of success. Based upon BMI, only 8 members of the study group were defined as successful, whereas based upon the women's perspectives, 11 members were successful. Participants' definitions of successful weight management were divergent from biomedical definitions and could be categorized into three perspectives: biomedical, reframed normal weight, and holistic. Women who ascribed to the biomedical definition of success embodied the cultural ideal of thinness by adhering to an underweight weight norm. Participants using the reframed normal weight definition of success rejected biomedical weight norms and created their own weight norms. The holistic perspective on success involved the use of a broader, health-focused definition of successful weight management and offers some directions for revising current health promotion care relative to weight.

Self in relation: a prolegomenon for holistic nursing

We have outlined some of the characteristics of holistic nursing and have named and explored the concepts that we believe are important to holistic practice. We have outlined assumptions that offer to nursing a more caring and connected way of interacting with clients than currently exists in nursing practice. We do not have answers to the questions of how to implement this practice within the structure of current nursing practice. Occasionally when we discuss these ideas with other nurses, they tell us that nursing as currently practiced in hospitals and community agencies is just the "real world," as though we had better get used to it. Maybe the world that we have presented is the "unreal world," for the moment at least. We are proud to live and learn in this unreal world and in a community of folks who make their living in holistic practice. If we had to make our living working in the "real world" of health care, could we do something to change it before the conflicts drove us away? The concluding question is, "Will nurses use their joint power to build therapeutic environments within nursing, or must they defect from nursing to practice holistic care?"

Body size values of white and black women

The purpose of this naturalistic study was to compare values held by 36 white and 31 black women related to body size, and to identify factors that influence these values and linkages between body size values and weight management activities. Black women of lower SES were significantly different from black women of higher SES and white women, regardless of SES, in that they were heavier, viewed themselves as heavier, and perceived attractive body size as heavier. Black lower status women had to become a great deal heavier than the other groups before they defined themselves as overweight. We suggest that black lower social status women have a wider range of "normal" and attractive body size and that this wider range is developed from comparisons of other women in their social milieu and influences the initiation of weight loss activities.

Longitudinal analysis of responses to oral didanosine therapy following zidovudine therapy in advanced infection with human immunodeficiency virus

The effect on immunologic and virological parameters of up to 24 weeks of therapy with didanosine at daily oral doses of < or = 12.5 mg/(kg.d) was studied retrospectively in 69 patients with advanced disease due to human immunodeficiency virus--i.e., AIDS or advanced AIDS-related complex--who had previously been treated with zidovudine. Patients entered the study with a low CD4 cell count (median, 39/microL) and with evidence of an ongoing depression of bone marrow function. Didanosine therapy was associated with a significant increase in CD4 counts and a prolonged decrease in serum levels of p24 antigen relative to baseline. These changes were more pronounced in the population with baseline CD4 counts of > or = 100/microL. A beneficial effect of didanosine therapy on hematologic parameters was observed in these patients, with increases during therapy of hemoglobin levels as well as white blood cell, granulocyte, and platelet counts. These responses were maximal at weeks 16-20. Further investigations are needed to establish the clinical correlates of these observations.

Long-term follow-up of didanosine administered orally twice daily to patients with advanced human immunodeficiency virus infection and hematologic intolerance of zidovudine

This phase 1 trial was conducted to evaluate the safety and tolerance of didanosine (ddI) in subjects with AIDS or AIDS-related complex (ARC) who previously had demonstrated hematologic intolerance of zidovudine. Thirty subjects, 21 with AIDS and nine with ARC, were enrolled. Initially, didanosine was administered orally twice daily for a total daily dose of either 750 mg or 1,500 mg. Subsequently, the dosage for those receiving 1,500 mg/d was reduced to a maximum of 750 mg/d (375 mg twice daily) when data from this and other phase 1 studies showed that the dosage of 1,500 mg/d (750 mg twice daily) was associated with an unacceptable risk of developing neuropathy. The subjects were studied for 46 weeks (mean time; range, 7-122 weeks). The dose-limiting toxic effect observed was peripheral neuropathy, which occurred in eight patients. Other significant toxic effects included pancreatitis in three patients and xerostomia in eleven. In general, didanosine was well tolerated from a hematologic standpoint by the majority of patients during prolonged administration.

Effects of therapy with didanosine on hematologic parameters in patients with advanced human immunodeficiency virus disease

Myelosuppression is associated with human immunodeficiency virus (HIV) infection and may also be produced by agents used for the treatment of the disease or the treatment of its complications. Didanosine (ddl; 2',3'-dideoxyinosine) is a newer purine nucleoside that has recently become available for therapy for HIV infection. The effects of didanosine on peripheral blood counts have been retrospectively evaluated in the first 170 patients treated with this new agent in four phase I trials. Patients treated with didanosine showed statistically significant improvements in hemoglobin levels, white cell counts, and granulocyte and platelet numbers as compared with baseline values. These changes were seen with or without prior therapy with zidovudine, were somewhat more pronounced at higher doses of didanosine, and persisted for up to 1 year. Reported adverse events included peripheral neuropathy, diarrhea, and most notably, pancreatitis. It is concluded that, while some toxic side effects occur, didanosine therapy in HIV infection is associated with an amelioration of HIV-induced myelosuppression.

Recombinant human granulocyte-macrophage colony-stimulating factor ameliorates zidovudine-induced neutropenia in patients with acquired immunodeficiency syndrome (AIDS)/AIDS-related complex

To evaluate the effect of recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) on patients with acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC) who were intolerant to zidovudine because of neutropenia, we performed a randomized, open-label study in which patients were assigned to one of two groups. Zidovudine was discontinued in group A patients before instituting GM-CSF treatment and was restarted in a graduated fashion over 4 weeks. Group B patients continued on full-dose (1,200 mg/d) zidovudine therapy while beginning GM-CSF therapy. A total of 17 patients were entered, eight in group A and nine in group B. Five of eight patients in group A and seven of nine in group B had a history of Pneumocystis carinii pneumonia (PCP). All were homosexual males, except one female in group A who was the sex partner of a bisexual male with AIDS. All patients had neutropenia (absolute neutrophil count [ANC] less than 1,000/microL) while taking full-dose zidovudine. The mean CD4 (+/- SD) lymphocyte level was 37 (+/- 29)/microL and 39 (+/- 44)/microL in groups A and B, respectively. After randomization, patients were begun on subcutaneous GM-CSF at a dose of 1.0 microgram/kg/d. Patients in group A received 2 weeks of daily GM-CSF, at which time zidovudine was restarted if the ANC was greater than 1,000/microL; if the ANC was less than 1,000/microL, the dose of GM-CSF was increased to 3.0 micrograms/kg, and at 2-week intervals either zidovudine was restarted or the dose of GM-CSF was increased to 5 micrograms/kg and then 10 micrograms/kg, to maintain the ANC greater than 1,000/microL. Group B patients received full-dose zidovudine concurrently with GM-CSF administration. The dose of GM-CSF was increased every 2 weeks if necessary to keep the ANC greater than 1,000/microL while maintaining full-dose zidovudine therapy. Patients in each group showed an increase in total white blood cell (WBC) count. Neutrophils and eosinophils were responsible for the majority of this increase. Patients in group A had a more rapid increase in WBC than those in group B; however, by week 8, the WBC in each group was essentially equal. Viral replication as measured by human immunodeficiency virus (HIV) p24 antigen (Ag) was decreased in four patients in each group, increased in one patient in each group, and remained unchanged in the remainder. The ability to culture virus from peripheral blood mononuclear cells was not changed by the regimen. The major toxicities of the regimen were fever and malaise.(ABSTRACT TRUNCATED AT 400 WORDS)

Phase I study of 2'-3'-dideoxyinosine administered orally twice daily to patients with AIDS or AIDS-related complex and hematologic intolerance to zidovudine

PURPOSE

To evaluate the safety and hematologic tolerance of 2'-3'-dideoxyinosine (didanosine, ddI) in subjects with acquired immunodeficiency syndrome (AIDS) or AIDS-related complex and prior hematologic intolerance to zidovudine.

PATIENTS AND METHODS

A Phase I trial with two dose groups at a single-center, university-affiliated hospital ambulatory care center. Of 30 subjects enrolled, 21 had AIDS and nine had AIDS-related complex. All had CD4 lymphocyte counts less than 0.2 x 10(9)/L at entry. Didanosine was administered orally twice daily at a total daily dose of 750 mg or 1,500 mg for 12 weeks. Subjects who completed the 12-week study continued to receive ddI at the lower dose. All subjects were monitored for toxicity. Virologic and immunologic response markers were also measured.

RESULTS

For the group as a whole, there was no significant decrease in mean hemoglobin level or leukocyte or platelet counts. The dose-limiting toxicity was peripheral neuropathy. Other significant toxicities included pancreatitis and hypocalcemia. Uric acid elevations were common but were without clinical consequence. A sustained decrease in serum p24 antigen of at least 50% was noted in 42% of subjects who were p24 antigen-positive at entry. The mean CD4 lymphocyte count showed an initial increase that was not sustained over the 12-week study. All subjects remained anergic to skin testing.

CONCLUSIONS

Didanosine is well tolerated hematologically in some patients with prior significant hematologic intolerance to zidovudine. The toxicity profile for ddI differs from that of zidovudine and includes peripheral neuropathy and pancreatitis. Changes in CD4 lymphocyte number and HIV p24 antigen levels in some patients suggest antiviral activity of ddI in this population.

To lose, to maintain, to ignore: weight management among women

The purpose of this study was to describe the process of weight management and the factors that influence this process in a sample of 37 middle-class and working-class white women of varied body size. A naturalistic study design, with a cultural-ecological theoretical orientation and ethnographic interviewing techniques, was used. The findings indicated that there were five stages through which women moved, repeatedly, as they managed weight: appraising, deemphasizing, mobilizing, enacting, and maintaining. Each stage consisted of multiple processes characterized by the use of personally developed tactics and strategies. Concern about appearance rather than health was a more salient factor in the initiation of weight-loss efforts. Progression through the five-stage pathway for weight management was influenced by time and informants' weight. Implications for practice include helping clients reduce the difficulty of altering cultural routines of eating and exercise and eliciting clients' own norms for body size.

Aerosol pentamidine prophylaxis following Pneumocystis carinii pneumonia in AIDS patients: results of a blinded dose-comparison study using an ultrasonic nebulizer

PURPOSE

To compare the efficacy and safety of three different doses of prophylactic aerosol pentamidine in patients with one prior episode of Pneumocystis carinii pneumonia (PCP) and the acquired immunodeficiency syndrome.

PATIENTS AND METHODS

The design of the study was a double-blind, randomized, dose-comparison clinical trial conducted at 13 medical centers within the United States. In stage I of the trial, patients were randomized to receive either 5 mg, 60 mg, or 120 mg of aerosol pentamidine delivered biweekly with the Fisoneb (Fisons, Inc., Rochester, New York) ultrasonic nebulizer. After 24 weeks of therapy, patients entered stage II of the trial, where the 5-mg group was re-randomized to either the 60-mg or 120-mg group.

RESULTS

One hundred seventy-five patients entered stage I of the trial and received prophylaxis for a mean of 123.6 days. Seven assigned to the 5-mg biweekly dosing schedule had a confirmed recurrence of PCP, compared with none in the 60-mg group (p = 0.007) and three in the 120-mg group (p = 0.304). During stage II of the trial, eight patients in the 60-mg group and one additional patient in the 120-mg group had recurrent PCP. After 52 weeks of observation, the likelihood of being PCP-free was 88.0% in the 60-mg group and 93% in the 120-mg group (p = 0.712). Minor adverse events related to aerosol pentamidine administration included cough, taste perversion, chest pain, bronchospasm, and dyspnea. These side effects were more common in the 60-mg and 120-mg treatment groups and resulted in withdrawal from the study by one patient. Serious events were more common after 24 weeks of therapy and included asymptomatic hypoglycemia (five), pancreatitis (two), pneumothorax (one), and extrapulmonary pneumocystosis (one).

CONCLUSIONS

These results demonstrate that biweekly administration of 60 mg or 120 mg of aerosol pentamidine significantly decreases PCP recurrence when compared with a 5-mg regimen or findings in historic controls and is generally well tolerated. There is no significant difference in effect or safety between these two dosing regimens in patients followed for at least 52 weeks of therapy.

Characterization of autoantibodies to the CD4 molecule in human immunodeficiency virus infection

Autoantibodies to the CD4 protein, which serves as a receptor for the human immunodeficiency virus (HIV) on the surface of target cells, were found in patients with different stages of HIV disease. Using recombinant soluble CD4 (rCD4) antigen in a enzyme-linked immunosorbent assay (ELISA), we detected serum anti-CD4 antibodies in approximately 20% of HIV-1 infected patients and 13% of HIV-2 infected patients. There was no correlation between the presence of anti-CD4 antibodies and the stage of HIV disease, serum IgG concentration, number of peripheral blood CD4 positive lymphocytes, or CD4/CD8 lymphocyte ratios in HIV-1 infected patients. Immunoaffinity purified anti-CD4 antibody failed to bind to CD4 positive cells using flow cytometric analysis. However, this antibody could weakly bind to CD4 positive cells that had been preincubated with purified recombinant gp120 (rgp120). In addition, using an ELISA system, we found that the binding of purified patient anti-CD4 antibody to rCD4 was increased in the presence of rgp120. Similar increased binding was observed with the anti-CD4 monoclonal antibody OKT4, but not with anti-Leu3a. These data suggest that a conformational change in the C-terminal domains of CD4 may be induced by gp120 binding and could lead to development of anti-CD4 antibodies.