Developing Multipollutant Exposure Indicators of Traffic Pollution: The Dorm Room Inhalation to Vehicle Emissions (DRIVE) Study.

Introduction: The Dorm Room Inhalation to Vehicle Emissions (DRIVE2) study was conducted to measure traditional single-pollutant and novel multipollutant traffic indicators along a complete emission-to-exposure pathway. The overarching goal of the study was to evaluate the suitability of these indicators for use as primary traffic exposure metrics in panel-based and small-cohort epidemiological studies. Methods: Intensive field sampling was conducted on the campus of the Georgia Institute of Technology (GIT) between September 2014 and January 2015 at 8 monitoring sites (2 indoors and 6 outdoors) ranging from 5 m to 2.3 km from the busiest and most congested highway artery in Atlanta. In addition, 54 GIT students living in one of two dormitories either near (20 m) or far (1.4 km) from the highway were recruited to conduct personal exposure sampling and weekly biomonitoring. The pollutants measured were selected to provide information about the heterogeneous particulate and gaseous composition of primary traffic emissions, including the traditional traffic-related species (e.g., carbon monoxide [CO], nitrogen dioxide [NO2], nitric oxide [NO], fine particulate matter [PM2.5], and black carbon [BC]), and of secondary species (e.g., ozone [O3] and sulfate as well as organic carbon [OC], which is both primary and secondary) from traffic and other sources. Along with these pollutants, we also measured two multipollutant traffic indicators: integrated mobile source indicators (IMSIs) and fine particulate matter oxidative potential (FPMOP). IMSIs are derived from elemental carbon (EC), CO, and nitrogen oxide (NOx) concentrations, along with the fractions of these species emitted by gasoline and diesel vehicles, to construct integrated estimates of gasoline and diesel vehicle impacts. Our FPMOP indicator was based on an acellular assay involving the depletion of dithiothreitol (DTT), considering both water-soluble and insoluble components (referred to as FPMOPtotal-DTT). In addition, a limited assessment of 18 low-cost sensors was added to the study to supplement the four original aims. Results: Pollutant levels measured during the study showed a low impact by this highway hotspot source on its surrounding vicinity. These findings are broadly consistent with results from other studies throughout North America showing decreased relative contributions to urban air pollution from primary traffic emissions. We view these reductions as an indication of a changing near-road environment, facilitated by the effectiveness of mobile source emission controls. Many of the primary pollutant species, including NO, CO, and BC, decreased to near background levels by 20 to 30 m from the highway source. Patterns of correlation among the sites also varied by pollutant and time of day. NO2 exhibited spatial trends that differed from those of the other single-pollutant primary traffic indicators. We believe this was caused by kinetic limitations in the photochemical chemistry, associated with primary emission reductions, required to convert the NO-dominant primary NOx, emitted from automobiles, to NO2. This finding provides some indication of limitations in the use of NO2 as a primary traffic exposure indicator in panel-based health effect studies. Roadside monitoring of NO, CO, and BC tended to be more strongly correlated with sites, both near and far from the road, during morning rush hour periods and often weakly to moderately correlated during other time periods of the day. This pattern was likely associated with diurnal changes in mixing and chemistry and their impact on spatial heterogeneity across the campus. Among our candidate multipollutant primary traffic indicators, we report several key findings related to the use of oxidative potential (OP)-based indicators. Although earlier studies have reported elevated levels of FPMOP in direct exhaust emissions, we found that atmospheric processing further enhanced FPMOPtotal-DTT, likely associated with the oxidation of primary polycyclic aromatic hydrocarbons (PAHs) to quinones and hydroxyquinones and with the oxidization and water solubility of metals. This has important implications in terms both of the utility of FPMOPtotal-DTT as a marker for exhaust emissions and of the importance of atmospheric processing of particulate matter (PM) being tied to potential health outcomes. The results from the personal exposure monitoring also point to the complexity and diversity of the spatiotemporal variability patterns among the study monitoring sites and the importance of accounting for location and spatial mobility when estimating exposures in panel-based and small-cohort studies. This was most clearly demonstrated with the personal BC measurements, where ambient roadside monitoring was shown to be a poor surrogate for exposures to BC. Alternative surrogates, including ambient and indoor BC at the participants' respective dorms, were more strongly associated with personal BC, and knowledge of the participants' mean proximity to the highway was also shown to explain a substantial level of the variability in corresponding personal exposures to both BC and NO2. In addition, untargeted metabolomic indicators measured in plasma and saliva, which represent emerging methods for measuring exposure, were used to extract approximately 20,000 and 30,000 features from plasma and saliva, respectively. Using hydrophilic interaction liquid chromatography (HILIC) in the positive ion mode, we identified 221 plasma features that differed significantly between the two dorm cohorts. The bimodal distribution of these features in the HILIC column was highly idiosyncratic; one peak consisted of features with elevated intensities for participants living in the near dorm; the other consisted of features with elevated intensities for participants in the far dorm. Both peaks were characterized by relatively short retention times, indicative of the hydrophobicity of the identified features. The results from the metabolomics analyses provide a strong basis for continuing this work toward specific chemical validation of putative biomarkers of traffic-related pollution. Finally, the study had a supplemental aim of examining the performance of 18 low-cost CO, NO, NO2, O3, and PM2.5 pollutant sensors. These were colocated alongside the other study monitors and assessed for their ability to capture temporal trends observed by the reference monitoring instrumentation. Generally, we found the performance of the low-cost gas-phase sensors to be promising after extensive calibration; the uncalibrated measurements alone, however, would likely not have led to reliable results. The low-cost PM sensors we evaluated had poor accuracy, although PM sensor technology is evolving quickly and warrants future attention. Conclusions: An immediate implication of the changing near-road environment is that future studies aimed at characterizing hotspots related to mobile sources and their impacts on health will need to consider multiple approaches for characterizing spatial gradients and exposures. Specifically and most directly, the mobile source contributions to ambient concentrations of single-pollutant indicators of traffic exposure are not as distinguishable to the degree that they have been in the past. Collectively, the study suggests that characterizing exposures to traffic-related pollutants, which is already difficult, will become more difficult because of the reduction in traffic-related emissions. Additional multi-tiered approaches should be considered along with traditional measurements, including the use of alternative OP measures beyond those based on DTT assays, metabolomics, low-cost sensors, and air quality modeling.

Population genetics of Schistosoma haematobium: development of novel microsatellite markers and their application to schistosomiasis control in Mali.

The recent implementation of mass drug administration (MDA) for control of uro-genital schistosomiasis has identified an urgent need for molecular markers to both directly monitor the impact of MDA, for example to distinguish re-infections from uncleared infections, as well as understand aspects of parasite reproduction and gene flow which might predict evolutionary change, such as the development and spread of drug resistance. We report the development of a novel microsatellite tool-kit allowing, for the first time, robust genetic analysis of individual S. haematobium larvae collected directly from infected human hosts. We genotyped the parasite populations of 47 children from 2 schools in the Ségou region of Mali, the first microsatellite study of this highly neglected parasite. There was only limited evidence of population subdivision between individual children or between the two schools, suggesting that few barriers to gene flow exist in this population. Complex relationships between parasite reproductive success, infection intensity and host age and gender were identified. Older children and boys harboured more diverse infections, as measured by the number of unique adult genotypes present. Individual parasite genotypes had variable reproductive success both across hosts, a pre-requisite for evolutionary selection, and, phenotypically, in hosts of different ages and genders. These data serve as a baseline against which to measure the effect of treatment on parasite population genetics in this region of Mali, and the tools developed are suitable to further investigate this important pathogen, and its close relatives, throughout their range.

Spermiogenesis defects in human: detection of transition proteins in semen from some infertile men.

Semen samples from 60 infertile men were examined by flow cytometry following propidium iodide staining. Of these, 23 samples contained young haploid cells. Transition proteins (TP1 and/or TP2) were detected in 12 of these, using immunohistochemical staining. The presence of TPs in spermatids in semen indicates inhibition in the differentiation pathway from round spermatids to spermatozoa. Cells of this type were found in semen from patients with nonobstructive azoospermia, severe to extreme cases of oligozoospermia, asthenozoospermia and teratozoospermia.

Inhibition of Escherichia coli beta-galactosidase by 2-nitro-1-(4,5-dimethoxy-2-nitrophenyl) ethyl, a photoreversible thiol label.

1-Nitro-2-phenylethene (beta-nitrostyrene, 1) which is a thiol-protecting reagent (Jung, G., Fouad, H. and Heusel, G. (1975) Angew. Chem. Int. Ed. Engl. 14, 817-818), was demonstrated in this work to be an irreversible inhibitor of beta-galactosidase (EC 3.2.1.23), an enzyme known to be inhibited by some thiol reagents or through modifying a methionine residue at the active site. No reversal of the inhibition was observed upon subsequent incubation with mercaptoethanol or irradiation (350 nm). 1-(4,5-dimethoxy-2-nitrophenyl)-2-Nitroethene 2) was also shown to be an irreversible inhibitor (94% inhibition, pH 8.3) of the enzyme. Kcat values of beta-galactosidase at pH 8.3 with o-nitrophenyl beta-D-galactopyranoside (ONPG) as the substrate and at the highest inhibitor concentrations employed for compound 1 (4.06 x 10(-4) M) ranged from 1.67 x 10(4) S-1 after 30 min of preincubation to <0.07 x 10(4) S-1 after 180 min preincubation. For compound 2 (9.5 x 10(-5) M) Kcat values ranged from 2.70 x 10(4) S-1 following 30 min preincubation to 1.15 x 10(4) S-1 after 180 min of preincubation; the changes in Km(app), however, were small. The activity was not recovered following incubation with mercaptoethanol. Since compound 2 and the inhibited enzyme are 2-nitrobenzyl derivatives, they are expected to be photosensitive and indeed, irradiation of the inhibited enzyme in the presence of mercaptoethanol resulted in recovery (89%, pH 8.3) of the enzyme activity.

Evidence for biological rhythm in spermatogenesis in the pubertal hamster (Mesocricetus auratus): a flow cytometric study.

The number of cells in the S-phase fraction of the cell cycle reflects proliferative activity. Using flow cytometry histograms and the Phoenix M+ cell cycle program, the percent of cells in the S-phase fraction was measured in single cell suspensions prepared from testes of hamsters of different ages. A cyclical pattern with a period of 9 days, superimposed on another rhythm with a 38 day period was observed (p < 0.01) during hamster maturation and it disappeared after the second spermatogenic wave, where the S phase values reached a plateau. It was concluded that maturing animals passed through a stage in which testicular biological rhythm was involved. Therefore it was concluded that it takes approximately two spermatogenic waves before the proliferation rate in the testis reached a steady state.

Production of zearalenone in vitro and in corn grains stored under modified atmospheres.

The production of zearalenone by an isolate of Fusarium equiseti was studied in chemically defined medium and in corn grains stored under modified atmospheres. An increase in the concentrations of sucrose or xylose in Czapek's medium resulted in increased toxin production, while no toxin was produced when lactose was present in the medium. Methionine (10(-2) and 10(-3) M) and cystine (10(-3) M) added to Czapek's medium inhibited zearalenone production. When amino acids or nitrogen salts were added as the sole nitrogen source, only alanine, tryptophan and NH4Cl totally inhibited zearalenone production. Zearalenone production was inhibited almost completely in high-moisture corn grains (27%) kept under atmospheres enriched with high CO2 levels (60%, 40% or 20%) with either 20% or 5% O2. However, a lower amount of CO2 was needed to inhibit fungal development and toxin formation when a reduced O2 level was applied.

Effects of pivalic acid and sodium pivalate on L-carnitine concentrations in the cauda epididymidis and on male fertility in the hamster.

In this study, administration of pivalic acid or its sodium salt was found to decrease the L-carnitine concentration in the epididymal lumen of the hamster; it also tested whether this decrease affected sperm cell motility, chromatin structure, or fertilizing capacity. Provision of pivalic acid or its sodium salt (20 mM or 40 mM) in the drinking water of mature male golden hamsters for 30 days reduced (by 72%, 75%, and 83% in three experiments) the L-carnitine concentration of the cauda epididymidis but did not inhibit sperm chromatin condensation, as assessed by flow cytometry. The treatments did not alter the location of motile sperm in the epididymidis nor did they appreciably affect the motility of sperm obtained from the distal cauda epididymidis. The numbers and percentage of ova that reached the 2-cell stage 36-40 h after uterine insemination with spermatozoa from control and treated hamsters served as a measure of sperm fertility. Treatment with pivalic acid or sodium pivalate did not render male hamsters infertile although it appeared to reduce the fertilizing ability of their spermatozoa. These results suggest that the high concentration of L-carnitine present in the lumen of the cauda epididymidis is not required for maturation of sperm chromatin or development of sperm motility.

Energy expenditure variations in soldiers performing military activities under cold and hot climate conditions.

This study assessed the energetic status of soldiers exposed to intense physical activities in cold and warm weather. Thirty subjects participated in a two-phase study group A (n = 18) in the winter phase and group B (n = 12) in the summer phase. Energy expenditure (EE) was measured by the doubly labeled water technique; after a single, oral dosing of 2H(2)18O, daily urine samples were collected for 12 successive days. Energy intake (EI) was assessed from detailed food records analyzed by computerized food charts. Energy balance was calculated as the difference between EI and EE for each subject. Mean (+/- SE) daily EE was 4,281 +/- 170 and 3,937 +/- 159 kcal/day for the winter and summer groups, respectively. Daily EI was 2,792 +/- 124 kcal/day in group A and almost identical in group B. A negative energy balance of 1,422 +/- 163 kcal/day and 924 +/- 232 kcal/day (not significant) was calculated for groups A and B, respectively. Energy expenditure is primarily determined by the level of activity rather than by climate conditions; EI is insufficient to offset the high energy requirements under these conditions.

Career plans for male-dominated occupations among female seniors in religious and secular high schools.

This study investigated the hypothesis that the religious beliefs of young women significantly affect their career planning. All female seniors (N = 315) in one public religious and two public secular high schools in Israel responded to inventories examining their (1) orientation to homemaking or career, (2) interest in male-dominated occupations, and (3) preference for male-dominated occupations. Results from regression analyses indicated that young women from the secular schools, as compared to those from the religious school, expressed greater interest in and preference for male-dominated occupations. In addition, religious orientation, more than other background variables, had predictive power for interest in and preference for male-dominated occupations.

[Evaluation of sperm samples from infertile men by flow cytometry].

INTRODUCTION: Human spermatogenesis begins at adolescence and continues throughout life. This process includes morphologic, cytologic and biological changes, leading to the formation of mature spermatozoa. Male infertility may be caused by several reasons, including oligozoospermia at variable degrees and complete absence of mature spermatozoa. Routine spermatogram, measuring sperm counts, motility and morphology, might not provide complete information in the evaluation of these cases. This study is aimed to evaluate the possible use of flow cytometry in the identification of different sperm cell populations in sperm samples obtained from infertile men, and in determining the different cell types in various groups of infertile men. MATERIALS AND METHODS: Sperm samples from normal and infertile men (the latter were azoospermic or oligoteratozoospermic OTA) underwent flow cytometry analysis, after preparation with TNE buffer and staining with Propidium Iodide. The separation of germinal cells into different populations, according to their DNA content and chromatin condensation, was evaluated. The WINMDI (http://fac.-scripps.edu, J. Trotter) software was used for data analysis. RESULTS: Flow cytometric analysis enabled identification of several cell populations in sperm samples, including haploid, diploid and tetraploid cells. Certain cellular distribution patterns were observed in sperm samples from infertile men: mature haploid cells, diploid cells, domination of tetraploid or non-mature haploid cells, and combination of these patterns. These patterns appeared in a statistically different manner among fertile and infertile men; the median value of mature haploid cells was higher in normal men (91%, compared to 85% in the OTA group and 0% in the azoospermic men), while the median value of diploid and tetraploid cells was higher in azoospermic men (72% and 8.5% respectively, compared to only 1% and 0% in normal men). CONCLUSIONS: These findings suggest that flow cytometry of sperm samples may serve as a non-invasive tool for investigations of male infertility and for identification of appropriate candidates for interventional treatment.

Isolation and characterization of the first polymorphic microsatellite markers for Schistosoma haematobium and their application in multiplex reactions of larval stages.

The ability of microsatellite loci to reveal genetic diversity within the trematode Schistosoma haematobium is demonstrated for the first time. Nine novel polymorphic microsatellite markers were isolated and their viability assessed on 36 S. haematobium adult worm individuals from three geographical populations. Allelic diversity and gene diversity ranged from two to seven and from 0.29 to 0.76, respectively, suggesting high variability between individuals and between unrelated populations. Three primers also amplified Schistosoma mansoni and two Schistosoma japonicum. The results suggest these primers are useful for population genetic analyses of S. haematobium.

Flow cytometry of human semen: a preliminary study of a non-invasive method for the detection of spermatogenetic defects.

BACKGROUND: The pathway of spermatogenesis involves the conversion of diploid stem cells (spermatogonia) to tetraploid primary spermatocytes, followed by meiosis and two cell divisions, first forming diploid secondary spermatocytes and then haploid round spermatids. Differentiation of round spermatids results in spermatozoa containing condensed chromatin. It has long been known that semen from patients with non-obstructive azoospermia or oligospermia contains small numbers of immature germinal cells. In this article, a flow cytometric procedure is described for assessing defects in spermatogenesis by identifying the ploidy of those immature cells. METHODS: Cells in semen samples from 44 infertile patients and 14 controls were stained with propidium iodide, which displays red fluorescence when intercalated between bases in double-stranded DNA. The resulting cell suspension was examined by quantitative flow cytometry, with excitation by laser light (488 nm) and red fluorescence recorded on a logarithmic scale to allow easy differentiation between intensities of tetraploid, diploid and haploid round spermatids, and spermatozoa containing condensed chromatin. RESULTS: The flow cytometric method differentiated between cases of 'Sertoli cell-only' syndrome (complete absence of tetraploid and haploid cells) and cases where spermatogenesis was blocked in meiosis or in spermiogenesis. Flow cytometric histograms from semen samples from normozoospermic, oligozoospermic and azoospermic patients fell into patterns that correlated well with the results obtained from testis histology findings. CONCLUSIONS: The method described may serve as a simple, non-invasive and reliable assay to help clinicians counsel patients with severe male infertility before referring them for testicular surgery to locate spermatozoa for ICSI.

Esterase D polymorphism in several population groups in Israel.

The genetic polymorphism of red blood cells esterase D (EsD) has been investigated in 9 population groups in Israel: Ashkenazi Jews, non-Ashkenazi Jews from North Africa, Iran, Turkey, Egypt, Balkan, Iraq, Yemen as well as Arabs living in Israel. The distribution of EsD1 and EsD2 genes among the 9 communities was not homogenous chi2 = 42.3; d.f. = 8; p less than 0.0005). The Ashkenazi and North African Jews had significantly lower frequencies of EsD2 (0.100 and 0.102 respectively) than did Yemenite Jews and Arabs (0.212 and 0.206 respectively). The other communities investigated showed intermediate values. A Jewish family from Greece carrying the rare allele EsD2 has been detected.