The Mechanical Response and Tolerance of the Anteriorly-Tilted Human Pelvis Under Vertical Loading

Military vehicle underbody blast (UBB) is the cause of many serious injuries in theatre today; however, the effects of these chaotic events on the human body are not well understood. The purpose of this research was to replicate UBB loading conditions on the human pelvis and investigate the resulting response in a controlled laboratory setting. In addition to better understanding the response of the human pelvis to high rate vertical loading, this test series also aimed to identify high rate injury thresholds. Twenty-seven post mortem human surrogate (PMHS) component pelvis tests were completed using the University of Virginia's (UVa) simulated blast rig under a range of loading conditions and postures. Of those tests, 17 were in the anteriorly-tilted posture and used to construct the human injury probability curve. Average seat pan (rigid) accelerations for this subset of tests ranged from 300 to 2400 g over 2 to 3 ms of positive phase duration. Post-test computed tomography (CT) scans and necropsies were performed to determine injuries and revealed a frequent occurrence of anterior and posterior injuries, resulting in unstable pelvis ring fractures. The resulting Human Injury Probability Curve (HIPC) yielded mean forces of 5529, 8516, and 12431 N as measured by mass compensated seat platen loadcells applied through the rigid seat to the bilateral ischium are associated with a 10, 25, and 50% risk for unstable pelvic ring sacrum fractures in an anteriorly-tilted pelvis (28° from vertical), respectively.

Comparative chemical genomics reveal that the spiroindolone antimalarial KAE609 (Cipargamin) is a P-type ATPase inhibitor

The spiroindolones, a new class of antimalarial medicines discovered in a cellular screen, are rendered less active by mutations in a parasite P-type ATPase, PfATP4. We show here that S. cerevisiae also acquires mutations in a gene encoding a P-type ATPase (ScPMA1) after exposure to spiroindolones and that these mutations are sufficient for resistance. KAE609 resistance mutations in ScPMA1 do not confer resistance to unrelated antimicrobials, but do confer cross sensitivity to the alkyl-lysophospholipid edelfosine, which is known to displace ScPma1p from the plasma membrane. Using an in vitro cell-free assay, we demonstrate that KAE609 directly inhibits ScPma1p ATPase activity. KAE609 also increases cytoplasmic hydrogen ion concentrations in yeast cells. Computer docking into a ScPma1p homology model identifies a binding mode that supports genetic resistance determinants and in vitro experimental structure-activity relationships in both P. falciparum and S. cerevisiae. This model also suggests a shared binding site with the dihydroisoquinolones antimalarials. Our data support a model in which KAE609 exerts its antimalarial activity by directly interfering with P-type ATPase activity.

Selective sorting and destruction of mitochondrial membrane proteins in aged yeast

Mitochondrial dysfunction is a hallmark of aging, and underlies the development of many diseases. Cells maintain mitochondrial homeostasis through a number of pathways that remodel the mitochondrial proteome or alter mitochondrial content during times of stress or metabolic adaptation. Here, using yeast as a model system, we identify a new mitochondrial degradation system that remodels the mitochondrial proteome of aged cells. Unlike many common mitochondrial degradation pathways, this system selectively removes a subset of membrane proteins from the mitochondrial inner and outer membranes, while leaving the remainder of the organelle intact. Selective removal of preexisting proteins is achieved by sorting into a mitochondrial-derived compartment, or MDC, followed by release through mitochondrial fission and elimination by autophagy. Formation of MDCs requires the import receptors Tom70/71, and failure to form these structures exacerbates preexisting mitochondrial dysfunction, suggesting that the MDC pathway provides protection to mitochondria in times of stress.

Mother-daughter asymmetry of pH underlies aging and rejuvenation in yeast

Replicative aging in yeast is asymmetric–mother cells age but their daughter cells are rejuvenated. Here we identify an asymmetry in pH between mother and daughter cells that underlies aging and rejuvenation. Cytosolic pH increases in aging mother cells, but is more acidic in daughter cells. This is due to the asymmetric distribution of the major regulator of cytosolic pH, the plasma membrane proton ATPase (Pma1). Pma1 accumulates in aging mother cells, but is largely absent from nascent daughter cells. We previously found that acidity of the vacuole declines in aging mother cells and limits lifespan, but that daughter cell vacuoles re-acidify. We find that Pma1 activity antagonizes mother cell vacuole acidity by reducing cytosolic protons. However, the inherent asymmetry of Pma1 increases cytosolic proton availability in daughter cells and facilitates vacuole re-acidification and rejuvenation.

DOI:http://dx.doi.org/10.7554/eLife.03504.001

Aging is a part of life—but its biological basis and, in particular, how aged cells give rise to young offspring (or progeny) has not been clearly established for any organism.

Budding yeast is a microorganism that is a valuable model to understand aging in more complex organisms like humans. Budding yeast cells undergo a process called ‘replicative aging’, meaning that each yeast mother cell produces a set number of daughter cells in her lifetime. However, when daughter cells arise from an aging mother cell, the daughter's age is ‘reset to zero’. How mother cells age, and how their daughters are rejuvenated, are questions that have been studied for decades.

Previously, researchers discovered that a mother cell's vacuole (an acidic compartment that stores important molecules that can become toxic) becomes less acidic as the mother cell ages. Daughter cells, on the other hand, have very acidic vacuoles, which was linked to their renewed lifespans. However, the mechanism behind this difference in the acidity of the vacuole between mother and daughter cells was unknown.

Now, Henderson et al. have found that a protein (called Pma1), which is found at the cell surface and pumps protons out of the cell, is present in mother cells but not in their newly-formed daughter cells. Furthermore, the Pma1 protein also accumulates as mother cells age. By pumping protons out of the cell, Pma1 effectively reduces the number of protons available to acidify the vacuole in the mother cell. However, because at first the daughter does not have Pma1, there are still plenty of protons inside the cell to acidify the vacuole.

When Henderson et al. reduced the activity of Pma1 in mother cells, the entire cell became more acidic, and so did their vacuoles. Conversely daughter cells engineered to have more Pma1 were less acidic and had less acidic vacuoles than normal.

Henderson et al. next asked whether reducing Pma1 activity to create a more acidic cell, could extend the lifespan of cells, and found that indeed cells with less Pma1 activity lived longer. As such, these findings indicate that an asymmetry in the acidity of the cell—caused by unequal levels of the Pma1 protein—contributes to reducing the lifespan of the mother cell and to rejuvenating the daughter cell. Thus Henderson et al. have identified one of the earliest events in the cellular aging process in budding yeast. Their findings suggest that an imbalance in an activity that is normally essential for cell survival (in this case, the activity of Pma1) can have long-term consequences for the cell that lead to aging.

DOI:http://dx.doi.org/10.7554/eLife.03504.002

Replicative age induces mitotic recombination in the ribosomal RNA gene cluster of Saccharomyces cerevisiae

Somatic mutations contribute to the development of age-associated disease. In earlier work, we found that, at high frequency, aging Saccharomyces cerevisiae diploid cells produce daughters without mitochondrial DNA, leading to loss of respiration competence and increased loss of heterozygosity (LOH) in the nuclear genome. Here we used the recently developed Mother Enrichment Program to ask whether aging cells that maintain the ability to produce respiration-competent daughters also experience increased genomic instability. We discovered that this population exhibits a distinct genomic instability phenotype that primarily affects the repeated ribosomal RNA gene array (rDNA array). As diploid cells passed their median replicative life span, recombination rates between rDNA arrays on homologous chromosomes progressively increased, resulting in mutational events that generated LOH at >300 contiguous open reading frames on the right arm of chromosome XII. We show that, while these recombination events were dependent on the replication fork block protein Fob1, the aging process that underlies this phenotype is Fob1-independent. Furthermore, we provide evidence that this aging process is not driven by mechanisms that modulate rDNA recombination in young cells, including loss of cohesion within the rDNA array or loss of Sir2 function. Instead, we suggest that the age-associated increase in rDNA recombination is a response to increasing DNA replication stress generated in aging cells.

Late glacial stage and holocene tropical ice core records from huascaran, peru

Two ice cores from the col of Huascarán in the north-central Andes of Peru contain a paleoclimatic history extending well into the Wisconsinan (Würm) Glacial Stage and include evidence of the Younger Dryas cool phase. Glacial stage conditions at high elevations in the tropics appear to have been as much as 8 degrees to 12 degrees C cooler than today, the atmosphere contained about 200 times as much dust, and the Amazon Basin forest cover may have been much less extensive. Differences in both the oxygen isotope ratio zeta(18)O (8 per mil) and the deuterium excess (4.5 per mil) from the Late Glacial Stage to the Holocene are comparable with polar ice core records. These data imply that the tropical Atlantic was possibly 5 degrees to 6 degrees C cooler during the Late Glacial Stage, that the climate was warmest from 8400 to 5200 years before present, and that it cooled gradually, culminating with the Little Ice Age (200 to 500 years before present). A strong warming has dominated the last two centuries.

Effects of emissions from different type of residential heating upon cyclic guanosine monophosphate (cGMP) in blood platelets of residents

We hypothesized that different types of residential heating would be associated with different levels of indoor carbon monoxide (CO) and further that this might result in a differential in the concentration of cyclic 3':5' guanosine monophosphate (cGMP) in blood platelets in exposed residents. Individuals, who were recruited from homes using different fuel for heating, donated a venous blood sample in the winter and in the summer. In the winter the median blood platelet cGMP value for the group using liquid propane gas (LPG) was 65% higher than for the group using piped natural gas for heating (p <0.001). Also in the group using LPG, the median concentration of cGMP in the winter was 39% higher than the summer median (p < 0.003). The mean indoor concentrations of CO were measured over a period of 1 week during the winter and were <1 ppm. We conclude that observed differences were associated with emissions from different types of heating but that CO exposure alone is too low to explain these.

A mother's sacrifice: what is she keeping for herself?

Individual cells of the budding yeast, Saccharomyces cerevisiae, have a limited life span and undergo a form of senescence termed replicative aging. Replicative life span is defined as the number of daughter cells produced by a yeast mother cell before she ceases dividing. Replicative aging is asymmetric: a mother cell ages but the age of her daughter cells is 'reset' to zero. Thus, one or more senescence factors have been proposed to accumulate asymmetrically between mother and daughter yeast cells and lead to mother-specific replicative senescence once a crucial threshold has been reached. Here we evaluate potential candidates for senescence factors and age-associated phenotypes and discuss potential mechanisms underlying the asymmetry of replicative aging in budding yeast.

Interactions between Mei4, Rec114, and other proteins required for meiotic DNA double-strand break formation in Saccharomyces cerevisiae

In most sexually reproducing organisms, meiotic recombination is initiated by DNA double-strand breaks (DSBs) formed by the Spo11 protein. In budding yeast, nine other proteins are also required for DSB formation, but the roles of these proteins and the interactions among them are poorly understood. We report further studies of the behaviors of these proteins. Consistent with other studies, we find that Mei4 and Rec114 bind to chromosomes from leptonema through early pachynema. Both proteins showed only limited colocalization with the meiotic cohesin subunit Rec8, suggesting that Mei4 and Rec114 associated preferentially with chromatin loops. Rec114 localization was independent of other DSB factors, but Mei4 localization was strongly dependent on Rec114 and Mer2. Systematic deletion analysis identified protein regions important for a previously described two-hybrid interaction between Mei4 and Rec114. We also report functional characterization of a previously misannotated 5' coding exon of REC102. Sequences encoded in this exon are essential for DSB formation and for Rec102 interaction with Rec104, Spo11, Rec114, and Mei4. Finally, we also examined genetic requirements for a set of previously described two-hybrid interactions that can be detected only when the reporter strain is induced to enter meiosis. This analysis reveals new functional dependencies for interactions among the DSB proteins. Taken together, these studies support the view that Mei4, Rec114, and Mer2 make up a functional subgroup that is distinct from other subgroups of the DSB proteins: Spo11-Ski8, Rec102-Rec104, and Mre11-Rad50-Xrs2. These studies also suggest that an essential function of Rec102 and Rec104 is to connect Mei4 and Rec114 to Spo11.

Cyclin-dependent kinase directly regulates initiation of meiotic recombination

Meiosis is a specialized cell division that halves the genome complement, producing haploid gametes/spores from diploid cells. Proper separation of homologous chromosomes at the first meiotic division requires the production of physical connections (chiasmata) between homologs through recombinational exchange of chromosome arms after sister-chromatid cohesion is established but before chromosome segregation takes place. The events of meiotic prophase must thus occur in a strictly temporal order, but the molecular controls coordinating these events have not been well elucidated. Here, we demonstrate that the budding yeast cyclin-dependent kinase Cdc28 directly regulates the formation of the DNA double-strand breaks that initiate recombination by phosphorylating the Mer2/Rec107 protein and thereby modulating interactions of Mer2 with other proteins required for break formation. We propose that this function of Cdc28 helps to coordinate the events of meiotic prophase with each other and with progression through prophase.

Synaptonemal complex formation: where does it start?

The synaptonemal complex is a prominent, evolutionarily conserved feature of meiotic prophase. The assembly of this structure is closely linked to meiotic recombination. A recent study in budding yeast reveals an unexpected role in centromere pairing for a protein component of the synaptonemal complex, Zip1. These findings have implications for synaptonemal complex formation.

H2B (Ser10) Phosphorylation is Induced during Apoptosis and Meiosis in S. cerevisiae

The nucleosome, composed of an octamer of highly conserved histone proteins and associated DNA, is the fundamental unit of eukaryotic chromatin. How arrays of nucleosomes are folded into higher-order structures, and how the dynamics of such compaction are regulated, are questions that remain largely unanswered. Our recent studies demonstrated that phosphorylation of histone H2B is necessary to induce cell death that exhibits phenotypic hallmarks of apoptosis including DNA fragmentation and chromatin condensation in yeast (serine 10)1 and in mammalian cells (serine 14)2. In this article, we extend these findings by uncovering a role for H2B phosphorylation at serine 10 (Ser10) in another biological event that is associated with dramatic alterations in higher-order chromatin structure, meiosis. Our data show strong staining, indicative of H2B (Ser10) phosphorylation, during the pachytene stage of yeast meiotic prophase. These data broaden the use of this phosphorylation mark in chromatin remodeling that closely correlates with chromatin compaction. How phosphorylation marks are translated into meaningful downstream events during processes as diverse as apoptosis and meiosis remain a challenge for future studies.

Tying synaptonemal complex initiation to the formation and programmed repair of DNA double-strand breaks

During meiosis, homologous chromosomes recombine and become closely apposed along their lengths within the synaptonemal complex (SC). In part because Spo11 is required both to make the double-strand breaks (DSBs) that initiate recombination and to promote normal SC formation in many organisms, it is clear that these two processes are intimately coupled. The molecular nature of this linkage is not well understood, but it has been proposed that SC formation initiates locally at the sites of ongoing recombination and in particular at the subset of sites that will eventually give rise to crossovers. To test this hypothesis, we examined further the relationship between DSBs and SC formation in Saccharomyces cerevisiae. SCs were monitored in a series of spo11 missense mutants with varying DSB frequencies. Alleles that blocked DSB formation gave SC phenotypes indistinguishable from a deletion mutant, and partial loss-of-function mutations with progressively more severe DSB defects caused corresponding defects in SC formation. These results strongly correlate SC formation with Spo11 catalytic activity per se. Numbers of Zip3 complexes on chromosomes, thought to represent the sites of SC initiation, also declined when Spo11 activity decreased, but in a markedly nonlinear fashion: hypomorphic spo11 alleles caused larger defects in DSB formation than in Zip3 complex formation. This nonlinear response of Zip3 closely paralleled the response of crossover recombination products. The quantitative relationship between Zip3 foci, SC formation, and crossing over strongly implicates crossover-designated recombination intermediates as the sites of SC initiation.

Occupational exposure of midwives to nitrous oxide on delivery suites

AIMS

To compare environmental and biological monitoring of midwives for nitrous oxide in a delivery suite environment.

METHODS

Environmental samples were taken over a period of four hours using passive diffusion tubes. Urine measurements were taken at the start of the shift and after four hours.

RESULTS

Environmental levels exceeded the legal occupational exposure standards for nitrous oxide (100 ppm over an 8 hour time weighted average) in 35 of 46 midwife shifts monitored. There was a high correlation between personal environmental concentrations and biological uptake of nitrous oxide for those midwives with no body burden of nitrous oxide at the start of a shift, but not for others.

CONCLUSIONS

Greater engineering control measures are needed to reduce daily exposure to midwives to below the occupational exposure standard. Further investigation of the toxicokinetics of nitrous oxide is needed.

Evaluation of personal, environmental and biological exposure of paediatric anaesthetists to nitrous oxide and sevoflurane

Paediatric anaesthetists are at higher risk of exposure to waste anaesthetic gases, which often exceed set safety limits. Recommended personal diffusive sampling techniques for monitoring exposure to waste anaesthetic gases may not give a true profile of exposure and hence biological sampling may also be necessary. We evaluated the exposure of paediatric anaesthetists to nitrous oxide and sevoflurane as assessed by personal environmental and biological samples. The influence of venue and technique, and the strength of the relationship among the various sampling techniques were analysed. The study found that exposure to nitrous oxide during paediatric anaesthetic inductions is still a major problem, although exposure to sevoflurane was usually within the accepted limits. The type of breathing system used and the presence of scavenging seem to influence this exposure, though surprisingly, the induction technique or the methods of airway control do not. No significant relationship was found between the various biological indicators measured.

The use of nitrous oxide in anaesthetic practice: a questionnaire survey

Where practicable, exposure to a hazardous substance should be eliminated or adequately controlled. A postal questionnaire survey was sent to 10% of consultants from the Association of Anaesthetists of Great Britain and Ireland, to identify the level of use of nitrous oxide in current anaesthetic practice and identify any change of practice over the last 5 years. Details of anaesthetic practice were requested in three areas: nitrous oxide usage, availability of medical air on anaesthetic machines and the use of total intravenous anaesthesia. Replies were received from 320 consultants (75%). Of these, 49% felt that, over the last 5 years, their use of nitrous oxide had decreased. Twenty per cent of anaesthetists felt that there should be some restriction in availability of nitrous oxide. Where medical air was available, 32% felt that they would use it frequently. A total of 263 (83%) stated that they use total intravenous anaesthesia to some extent. The results showed that, although 49% of consultant anaesthetists had reduced their use of nitrous oxide, this was due to medical considerations rather than concerns over health and pollution issues arising from the use of nitrous oxide.

Biological monitoring of midwives' exposure to N(2)O using the Bio-VOC breath sampler

The use of exhaled breath as a biological monitoring tool is still not widely used. Although there are now commercially available kits, there are limited data on biological guidance values for all but a few substances for breath monitoring. The study investigated the possibility of using an indirect breath sampler to measure the levels of nitrous oxide in the exhaled breath of midwives at a midpoint during their shift. Levels of nitrous oxide in the exhaled breath were measured at (0-727 ppm) with a mean level of 64 ppm. The correlation between the established personal environmental monitoring and exhaled breath monitoring was generally poor as was the correlation between duration of nitrous oxide exposure and levels in the exhaled breath. Clearly the use of exhaled breath as a tool for biological monitoring is more appropriate than other invasive procedures. The breath sampler used has been a readily acceptable tool for occupational hygiene monitoring in a busy hospital ward.

Sociocultural perspectives on physical activity in the lives of older African American and American Indian women: a cross cultural activity participation study

Illuminating the diversity and sociocultural specificity of women's experiences may be important if healthy lifestyles and quality of life are to be achieved. The incidence of cardiovascular disease linked to physical inactivity is high among African American and American Indian women. If more is understood about the experience of physical activity involvement, healthier living might be encouraged. Therefore, the purpose of this study was to explore the sociocultural meanings of physical activity for older (over the age of 40 years) African American and American Indian women who participated in the Cross Cultural Activity Participation Study (CAPS). Through qualitative in-depth interviews, we explored how sociocultural perspectives are related to perceptions about physical activity. Gender and other sociocultural factors influenced physical involvement on a continuum from negligible to significant. Both groups interviewed showed evidence that opportunities for physical activity in their free time did not always exist for them. For African American women, history and daily living issues were important factors limiting their involvement. Marginality limited American Indian women, but their cultural pride was often a source of physical activity. The juxtaposition of cultural and personal values emerged as a determinant of physical activity involvement among the women in this study. A further expansion of cultural and personal life situation perspectives is recommended to help understand the complex dimensions of physical activity as it relates to healthy living.

Enablers and constraints to walking for older African American and American Indian women: the Cultural Activity Participation Study

Walking is a significant physical activity undertaken by a range of women from different ages, economic backgrounds, and family situations. The purpose of this analysis was to examine what conditions enabled walking to occur and what constraints prevented some older African American and American Indian women from walking as a physical activity. A descriptive analysis emerged related to three dimensions: the context of walking, how walking was enabled, and constraints to walking more or achieving greater satisfaction with walking as a physical activity. As more is known about how and why a behavior such as walking occurs, more can be done to raise the physical and mental quality of life for all people, regardless of race or gender.

A high-resolution millennial record of the south asian monsoon from himalayan ice cores

A high-resolution ice core record from Dasuopu, Tibet, reveals that this site is sensitive to fluctuations in the intensity of the South Asian Monsoon. Reductions in monsoonal intensity are recorded by dust and chloride concentrations. The deeper, older sections of the Dasuopu cores suggest many other periods of drought in this region, but none have been of greater intensity than the greatest recorded drought, during 1790 to 1796 A.D. of the last millennium. The 20th century increase in anthropogenic activity in India and Nepal, upwind from this site, is recorded by a doubling of chloride concentrations and a fourfold increase in dust. Like other ice cores from the Tibetan Plateau, Dasuopu suggests a large-scale, plateau-wide 20th-century warming trend that appears to be amplified at higher elevations.

Environmental monitoring of nitrous oxide during dental anaesthesia

AIM

The study was carried out to see if levels of nitrous oxide in dental theatres and community dental clinics were being controlled in accordance with the Control of Substances Hazardous to Health Regulations.

SETTING

A multi-centre study looked at exposure levels in a dental teaching hospital and two community dental clinics in the South Wales area between 1997 and 1998.

METHODS

A MIRAN infra-red spectrophotometer was used to measure static levels of nitrous oxide during general anaesthesia and conscious sedation. NIOSH method 6600 was used to collect personal samples of the individual administering the anaesthetic.

RESULTS

The results showed compliance with the regulations when averaged out over an 8 hour time weighted average. However, over short periods of time peak concentrations of up to 1190 ppm were observed through static sampling, and up to 734 ppm through personal sampling.

CONCLUSIONS

The results highlighted the need to provide adequate control measures such as anaesthetic gas scavenging, to reduce occupational exposure to dental staff in dental operating theatres and community dental clinics, therefore providing a safe working environment.

Staff exposure to anaesthetic gases in theatre and non theatre areas

Environmental monitoring of anaesthetic gases was carried out in theatre areas in eight hospitals as well as in Delivery suites, radiology, radiotherapy and Dental suites. High staff exposures occurred in nontheatre areas although exposures in theatres were generally satisfactory. Environmental control measures are required where staff exposures exceed legal standards.

An environmental survey of compliance with Occupational Exposure Standards (OES) for anaesthetic gases

Environmental monitoring of nitrous oxide and volatile agents was carried out between August 1996 and October 1997 within operating theatre areas in eight hospitals within the Bro Taf Health Authority. Static monitoring and personal sampling were undertaken to assess compliance with the Occupational Exposure Standards introduced in January 1996 by the Health and Safety Executive for anaesthetic agents. The monitoring concentrated on nitrous oxide with the results showing that compliance was being achieved. Limited monitoring was carried out of the volatile agents, which again were well below the Occupational Exposure Limits. Monitoring was also carried out in nontheatre areas in which anaesthetic agents were used. The results show that many of these locations, such as delivery suites and radiology units, have inadequate ventilation and no anaesthetic gas scavenging, both of which combined to produce levels that exceeded the standards.

A 25,000-year tropical climate history from bolivian ice cores

Ice cores that were recovered from the summit of Sajama mountain in Bolivia provide carbon-14-dated tropical records and extend to the Late Glacial Stage (LGS). Oxygen isotopic ratios of the ice decreased 5.4 per mil between the early Holocene and the Last Glacial Maximum, which is consistent with values from other ice cores. The abrupt onset and termination of a Younger Dryas-type event suggest atmospheric processes as the probable drivers. Regional accumulation increased during the LGS, during deglaciation, and over the past 3000 years, which is concurrent with higher water levels in regional paleolakes. Unlike polar cores, Sajama glacial ice contains eight times less dust than the Holocene ice, which reflects wetter conditions and extensive snow cover.

Measuring physical activity in midlife, older, and minority women: issues from an expert panel

This article summarizes the findings of an exploratory meeting of 53 experts brought together under the aegis of the Women's Health Initiative to identify important issues related to measuring physical activity in minority women, women in midlife (aged 40-75), and older women (aged > 75). The findings address five areas, three dealing with measurement and two concerning the design of surveys: (1) population characteristics to consider when measuring the physical activity of women and minority populations, (2) activity dimensions relevant to physical activity surveys, (3) measuring moderate and intermittent activities, (4) designing and administering physical activity surveys for older and minority women, and (5) establishing the reliability and validity of such physical activity surveys. Although the focus of the expert panel meeting was on identifying issues related to the measurement of physical activity in women, many issues summarized here can be generalized to children and men. The panel's findings concerning measuring physical activity are timely, as they directly bear on the challenges associated with the physical activity guidelines jointly issued by the Centers for Disease Control and Prevention and the American College of Sports Medicine and the recommendations made in the Surgeon General's 1996 report, Physical Activity and Health.

Environmental monitoring during gaseous induction with sevoflurane

Recent research has shown that gaseous induction in adults with sevoflurane is an acceptable technique. This study was undertaken to assess if gaseous induction using sevoflurane carried in both oxygen alone, and in nitrous oxide and oxygen combined, would provide acceptable pollution levels. As an occupational exposure standard has not been set for sevoflurane, we used the target level of 20 ppm set by the manufacturer. Environmental monitoring was carried out in the anaesthetic room during eight lists where consecutive triple vital capacity sevoflurane inductions were performed. Time-weighted averages for both gases over the duration of the lists were well below the occupational exposure standards (mean 1.1 (range 0.6-1.7) for sevoflurane and 17.3 (12-23) for nitrous oxide). There were high peak concentrations during the induction process (8.3 (4.1-17) for sevoflurane and 172.4 (65-310) for nitrous oxide) although these decreased to low concentrations between anaesthetic inductions. Personal sampling was carried out from the anaesthetist's breathing zone and concentrations were also low (1.2 (0.8-2.1) for sevoflurane and 45.9 (10.1-261.6) for nitrous oxide.

Physical findings and symptoms of depot medroxyprogesterone acetate use in adolescent females

STUDY OBJECTIVE

To document physical and symptomatic changes in adolescent females using depot medroxyprogesterone acetate (DMPA) for contraception.

DESIGN

A 30-month prospective experimental study using a convenience sample of subjects.

SETTING

A pediatric primary care clinic in Milwaukee, Wisconsin that serves an urban population of low socioeconomic status.

PARTICIPANTS

A mostly African-American group of 53 patients (mean age 16.5 +/- 1.3 years).

INTERVENTIONS

Subjects received 150 mg DMPA intramuscularly in either the deltoid or gluteus muscle. The first two DMPA injections were given 6-8 weeks apart in an effort to decrease menstrual irregularity. Subsequent injections were given every 3 months. A questionnaire was administered at each visit to document physical and symptomatic changes.

MAIN OUTCOME MEASURES

Included weight change, frequency and amount of menstrual bleeding, and perceived side effects and satisfaction both documented with a 5-point Likert scale.

RESULTS

At 5, 11, and 17 months of DMPA use, 75%, 40%, and 19% of subjects continued DMPA. The most commonly perceived side effects were weight gain (27%), headache (25%), irregular periods (24%), fatigue (23%), abdominal pain (18%), and decreased sexual desire (15%). Significant weight gain was noted with an average increase of 6.0 +/- 6.0 kg at 11 months of DMPA use and 9.0 +/- 5.4 kg at 17 months. No menstrual bleeding was experienced by 30%-40% of adolescents in any 3-month injection period, and those who bled averaged 8-13 days of bleeding between injections. No pregnancies occurred and 87% of patients were either satisfied or very satisfied with DMPA as a method of contraception.

CONCLUSION

Despite the documented side effects, DMPA is an effective, acceptable contraceptive for some adolescent females who are at high risk for pregnancy.

"I have a soul that dances like Tina Turner, but my body can't": physical activity and women with mobility impairments

The purpose of this study was to explore the experiences and meanings of physical activity for women with disabilities and to interpret the implications of physical activities specifically for women with mobility impairments. In-depth qualitative interviews were used to uncover data about how women with mobility impairments experienced physical activity and leisure. Emerging themes addressed the value of physical activity, attitudes toward one's disability and participation in physical activity, and conditions necessary for involvement in physical activity. Four values were associated with physical activities: leisure, therapy, maintenance, or perceived little value. Attitudes toward one's disability and physical activity resulted in conforming, resisting, or adjusting behavior. Energy/stamina/low pain level, transportation, removal of social fears, accessibility, and social support were the individual or combined conditions that influenced values and attitudes regarding physical activities. The results of this study highlighted the need to consider and improve opportunities for physical activity for women with mobility impairments.

Acid and alkaline phosphatase in bovine antral follicles

Acid and alkaline phosphatases were measured in the follicular fluid of 766 individual follicles from 96 cows. Follicles were obtained by bilateral ovariectomy or at slaughter from animals at various stages of the estrous cycle and pregnancy. Mean follicle size varied with the physiological state of the cow (P less than .0001). Acid phosphatase activity (U/microliters) varied inversely with follicle size (P less than .001) but not with stage of the estrous cycle or gestation. Total acid phosphatase activity per follicle increased with follicle size (P less than .05). Neither acid phosphatase nor alkaline phosphatase concentration was associated with atresia. Alkaline phosphatase activity (U/microliters) was greater in the smallest follicles (less than 50 microliters) than in other size groups (P less than .0001). Alkaline phosphatase activity (U/microliters) was greater (P less than .05) during the preovulatory phase of the estrous cycle than during other phases. A high concentration of follicular fluid phosphatases cannot be used as a marker for atresia but is characteristic of healthy small antral follicles.