Quantification of seven microbial volatile organic compounds in human serum by solid-phase microextraction gas chromatography-tandem mass spectrometry.

Microbial volatile organic compounds (MVOCs) are primary and secondary metabolites of fungal and bacterial growth. Changes in environmental conditions (e.g., humidity, light, oxygen, and carbon dioxide) influence microbial growth in indoor environments. Prolonged human exposure to MVOCs has been directly associated with sick building syndrome (SBS), respiratory irritation, and asthma-like symptoms. However, no method exists for assessing MVOC exposure by quantifying them in human serum. We developed a novel, high-throughput automated method for quantifying seven MVOCs (3-methylfuran, 2-hexanone, 2-heptanone, 3-octanone, 1-octen-3-ol, 2-ethyl-1-hexanol, and geosmin) in human serum. The method quantifies the target analytes using solid-phase microextraction gas chromatography-tandem mass spectrometry at low parts-per-billion levels. Limits of detection ranged from 0.076 to 2.77 µg/L. This method provides excellent linearity over the concentration range for the analytes, with coefficients of determination >0.992. Recovery in human serum was between 84.5% and 113%, and analyte precision ranged from 0.38% to 8.78%. The intra-day and inter-day reproducibility showed coefficients of variation ≤11% and ≤8%, respectively. Accurate and precise quantification of MVOCs is necessary for detecting and quantifying harmful human exposures in environments with active microbial growth. The method is well suited for high-throughput analysis to aid investigations of unhealthy exposures to microbial emissions.

Factors Associated with Exposure to Trihalomethanes, NHANES 2001-2012.

Disinfection is critical for maintaining a safe water supply, but the use of chlorine or chloramine leads to exposure to disinfection byproducts (DBPs), including trihalomethanes (THMs), which have been associated with adverse reproductive outcomes and bladder cancer. The U.S. Environmental Protection Agency revised the DBP regulations starting in 1998 to further limit levels of THMs in household water. We analyzed data from the National Health and Nutrition Examination Survey (NHANES) collected between 2001 and 2012 (with 2 years per cycle) using models with and without water-related predictors to examine the utility of including these measures. Median blood chloroform levels (25th-75th percentiles) were 16.2 (9.13-31.2) ng/L in 2001-2002 and 5.97 (2.92-12.3) ng/L in 2011-2012. Median blood bromodichloromethane (BDCM) levels (25th-75th percentiles) were 2.22 (1.06-4.61) ng/L in 2001-2002 and 1.18 (

Nitromethane Exposure from Tobacco Smoke and Diet in the U.S. Population: NHANES, 2007-2012.

Nitromethane is a known toxicant and suspected human carcinogen. Exposure to nitromethane in a representative sample of the civilian, noninstitutionalized population in the United States ≥12 years old was assessed using 2007-2012 National Health and Nutritional Examination Survey (NHANES) data. Nitromethane was detected in all 8000 human blood samples collected, of which 6730 were used for analyses reported here. Sample-weighted median blood nitromethane was higher among exclusive combusted tobacco users (exclusive smokers; 774 ng/L) than nonusers of tobacco products (625 ng/L). In stratified sample-weighted regression analysis, smoking 0.5 pack of cigarettes per day was associated with a statistically significant increase in blood nitromethane by 150 ng/L, and secondhand smoke exposure (serum cotinine >0.05 ng/mL and <10 ng/mL) was statistically significant with a 31.1 ng/L increase in blood nitromethane. Certain dietary sources were associated with small but statistically significant increases in blood nitromethane. At median consumption levels, blood nitromethane was associated with an increase of 7.55 ng/L (meat/poultry), 9.32 ng/L (grain products), and 14.5 ng/L (vegetables). This is the first assessment of the magnitude and relative source apportionment of nitromethane exposure in the U.S. population.

Quantification of 19 Aldehydes in Human Serum by Headspace SPME/GC/High-Resolution Mass Spectrometry.

Sources of human aldehyde exposure include food additives, combustion of organic matter (tobacco smoke), water disinfection byproducts via ozonation, and endogenous processes. Aldehydes are potentially carcinogenic and mutagenic, and chronic human aldehyde exposure has raised concerns about potential deleterious health effects. To aid investigations of human aldehyde exposure, we developed a novel method to measure 19 aldehydes released from Schiff base protein adducts in serum using controlled acid hydrolysis, solid-phase microextraction (SPME), gas chromatography (GC), and high-resolution mass spectrometry (HRMS). Aldehydes are released from Schiff base protein adducts through acid hydrolysis, and are quantified in trace amounts (µg/L) using stable isotope dilution. Detection limits range from 0.1 to 50 µg/L, with calibration curves spanning 3 orders of magnitude. The analysis of fortified quality control material over a three-month period showed excellent precision and long-term stability (3-22% CV) for samples stored at -70 °C. The intraday precision is also excellent (CV, 1-10%). The method accuracy ranges from 89 to 108% for all measured aldehydes, except acrolein and crotonaldehyde, two aldehydes present in tobacco smoke; their analysis by this method is not considered robust due in part to their reactivity in vivo. However, results strongly suggest that propanal, butanal, isobutanal, and isopentanal levels in smokers are higher than levels in nonsmokers, and thus may be useful as biomarkers of tobacco smoke exposure. This method will facilitate large epidemiological studies involving aldehyde biomonitoring to examine nonoccupational environmental exposures.

Blood screen findings in a 2-year cohort of newly arrived refugees to Sydney, Australia.

OBJECTIVES: To describe the prevalence of certain health conditions in newly arrived refugees to Sydney, Australia, and thereby help inform screening practices. STUDY TYPE: A clinical audit of routinely collected pathology results. METHODS: Demographics and pathology results from a nurse-led health assessment program for newly arrived refugees during 2013 and 2014 were analysed. Prevalences of screened conditions were calculated, and compared by country of birth and other demographic features. A specific category was created for those from Middle Eastern countries, for comparative analysis. RESULTS: Pathology results were analysed for 3307 people from 4768 seen by the assessment program (69.4%). Anaemia was found in 6% of males and 7.6% of females. Vitamin D deficiency (<50 nmol/L) was detected in 77.5%. Chronic hepatitis B was found in only 1.7% but in more than 10% of people from Burmese and Tibetan backgrounds. Strongyloides seropositivity was found in 4%. Among the subset tested for hepatitis C antibody, 0.5% were positive. No human immunodeficiency virus (HIV) infections were detected. More than 75% of the study population was from Middle Eastern countries. Compared with refugees from other regions, this subset had less anaemia (in females), more vitamin D deficiency, less chronic hepatitis B and less strongyloides seropositivity. CONCLUSIONS: People from refugee backgrounds have differing risks of conditions, based on demographics, migration history and prior screening. Postarrival testing should be tailored to each family and individual. Results of screening should be constantly reviewed and the approach updated based on findings. We support, in particular, the Canadian approach of only retesting HIV in refugees from countries with a high prevalence of infection (>1%).

Transition from an asylum seeker-specific health service to mainstream primary care for community-based asylum seekers: a qualitative interview study.

BACKGROUND AND AIM: Transition of asylum seekers from special-purpose health services to mainstream primary care is both necessary and difficult. This study explores the issues encountered by asylum seekers undergoing this transition in Sydney, Australia. METHODS: Qualitative semistructured interviews were conducted with nine asylum seeker patients and nine staff working in the sector. RESULTS: Asylum seekers faced significant challenges in the transition to mainstream primary care. Contributing factors included the complexity of health and immigration systems, the way in which asylum seeker-specific services provide care, lack of understanding and accommodation by mainstream general practioner (GP) services, asylum seekers' own lack of understanding of the health system, mental illness, and social and financial pressures. CONCLUSIONS: There is a need for better preparation of asylum seekers for the transition to mainstream primary care. Mainstream GPs and other providers need more education and support so that they can better accommodate the needs of asylum seeker patients. This is an important role for Australia's refugee health services and Primary Health Networks.

The Australasian Society for Infectious Diseases and Refugee Health Network of Australia recommendations for health assessment for people from refugee-like backgrounds: an abridged outline.

INTRODUCTION: In 2009, the Australasian Society of Infectious Diseases published guidelines on the post-arrival health assessment of recently arrived refugees. Since then, the number of refugees and asylum seekers reaching Australia has increased substantially (17 555 refugees in 2015-16) and the countries of origin have changed. These groups are likely to have had poor access to health care pre-arrival and, consequently, are at risk of a range of chronic and infectious diseases. We established an advisory group that included infectious diseases physicians, general practitioners, public health specialists, paediatricians and refugee health nurses to update the 2009 guidelines.Main recommendations: All people from refugee-like backgrounds, including children, should be offered a tailored comprehensive health assessment and management plan, ideally within 1 month of arrival in Australia. This can be offered at any time if initial contact with a GP or clinic is delayed. Recommended screening depends on history, examination and previous investigations, and is tailored based on age, gender, countries of origin and transit and risk profile. The full version of the guidelines is available at http://www.asid.net.au/documents/item/1225.Changes in management as a result of this guideline: These guidelines apply to all people from refugee-like backgrounds, including asylum seekers. They provide more information about non-communicable diseases and consider Asia and the Middle East as regions of origin as well as Africa. Key changes include an emphasis on person-centred care; risk-based rather than universal screening for hepatitis C virus, malaria, schistosomiasis and sexually transmissible infections; updated immunisation guidelines; and new recommendations for other problems, such as nutritional deficiencies, women's health and mental health.

Australian population cohort study of newly arrived refugee children: how effective is predeparture measles and rubella vaccination?

BACKGROUND: Predeparture medical screening and measles-mumps-rubella vaccination are routinely given to refugee children before departure from most transit countries en route to Australia. OBJECTIVES: The purpose of this study was to evaluate the effectiveness of this single measles-mumps-rubella vaccine and the reliability of its documentation. This is important in determining refugees' susceptibility to measles and rubella and the risk to the nonvaccinated community. METHODS: We analyzed measles and rubella serology in a comprehensively screened population of newly arrived refugees. We reviewed seropositivity rates based on age, sex, country of departure and vaccine documentation. RESULTS: Of 164 children screened, 139 (84.8%) were immune to rubella; 143 (87.7%) to measles and 119 (73.0%) to both. There was no significant difference in immunity among those of different ages or those departing different continents. Immunity rates among those with documented measles-mumps-rubella tended to be higher: 91.1% for rubella, 89.1% for measles and 80.0% for both diseases, but this did not reach significance at the 5% level. There was a significant difference between males (65.9%) and females (81.3%) immune to both diseases (P = 0.042). CONCLUSIONS: This cohort demonstrated similar measles and rubella seropositivity rates to those of the Australian population, but lower rates than population seroconversion studies, which have been estimated at 95%. Males were less likely to be immune. Rates in those with documented vaccination approximated seroconversion studies. This confirms the appropriateness of current guidelines which suggest that immunization is not required in the face of documented prior vaccination, but is required without such documentation.

The NSW Refugee Health Service - improving refugee access to primary care.

People of refugee background living in Australia can have significant physical and emotional healthcare needs. However, their ability to access mainstream health services, including general practitioners, may be limited by factors such as lack of familiarity with the health system, language and cultural barriers, and cost. There are a number of ways in which GPs can be involved and various sources of support available. With minor modifications to practice logistics and consultations, GPs can provide beneficial and rewarding healthcare for this disadvantaged group of families and individuals.

Access to primary health care services by community-based asylum seekers.

OBJECTIVES: To determine whether community-based asylum seekers experience difficulty in gaining access to primary health care services, and to determine the impact of any difficulties described. DESIGN, SETTING AND PARTICIPANTS: Qualitative study using semi-structured interviews between September and November 2010. Participants were community-based asylum seekers who attended the Asylum Seekers Centre of New South Wales, and health care practitioners and staff from the Asylum Seekers Centre and the NSW Refugee Health Service. RESULTS: We interviewed 12 asylum seekers, three nurses, one general practitioner and one manager. Asylum seekers' responses revealed that their access to primary health care was limited by a range of barriers including Medicare ineligibility, health care costs and the effects of social, financial and psychological stress. Limited access contributed to physical suffering and stress in affected asylum seekers. Participants providing care noted some improvement in access after recent government policy changes. However, they noted inadequate access to general practitioners, and dental, mental health and maternity care, and had difficulty negotiating pro-bono services. Both groups commented on the low availability of interpreters. CONCLUSIONS: Access to primary health care in Australia for community-based asylum seekers remains limited, and this has a negative effect on their physical and mental health. Further action is needed to improve the affordability of health care and to increase the provision of support services to community-based asylum seekers; extending Medicare eligibility would be one way of achieving this.

Distinguishing the roles of Topoisomerases I and II in relief of transcription-induced torsional stress in yeast rRNA genes.

To better understand the role of topoisomerase activity in relieving transcription-induced supercoiling, yeast genes encoding rRNA were visualized in cells deficient for either or both of the two major topoisomerases. In the absence of both topoisomerase I (Top1) and topoisomerase II (Top2) activity, processivity was severely impaired and polymerases were unable to transcribe through the 6.7-kb gene. Loss of Top1 resulted in increased negative superhelical density (two to six times the normal value) in a significant subset of rRNA genes, as manifested by regions of DNA template melting. The observed DNA bubbles were not R-loops and did not block polymerase movement, since genes with DNA template melting showed no evidence of slowed elongation. Inactivation of Top2, however, resulted in characteristic signs of slowed elongation in rRNA genes, suggesting that Top2 alleviates transcription-induced positive supercoiling. Together, the data indicate that torsion in front of and behind transcribing polymerase I has different consequences and different resolution. Positive torsion in front of the polymerase induces supercoiling (writhe) and is largely resolved by Top2. Negative torsion behind the polymerase induces DNA strand separation and is largely resolved by Top1.

A polio intervention in East African refugees to NSW.

This paper summarises a public health intervention in Sydney, NSW in late 2006 that resulted from the potential exposure of a number of refugees to polio virus while in transit in Nairobi, Kenya. The intervention involved the attempted follow-up of 113 persons at risk, assessment for symptoms and immunisation where indicated. No symptomatic cases were found. Seventy-five people were immunised with inactivated poliomyelitis vaccine. The intervention highlighted the importance of close collaboration between health services, the Department of Immigration and Citizenship and settlement service agencies, and provided several lessons to consider when assessing newly arrived refugees.

Method for quantifying nitromethane in blood as a potential biomarker of halonitromethane exposure.

The cytotoxicity and genotoxicity of nitromethane and its halogenated analogues in mammals raise concerns about potential toxicity to humans. This study shows that halonitromethanes are not stable in human blood and undergo dehalogenation to form nitromethane. We quantified nitromethane in human blood using solid-phase microextraction (SPME) headspace sampling coupled with gas chromatography (GC) and high resolution mass spectrometry (HRMS). The limit of detection was 0.01 microg/L with a linear calibration curve spanning 3 orders of magnitude. This method employs isotope dilution to precisely quantify trace amounts of nitromethane (coefficient of variation <6%). At three spiked concentrations of nitromethane, method accuracy ranged from 88 to 99%. We applied this method to blood samples collected from 632 people with no known occupational exposure to nitromethane or halonitromethanes. Nitromethane was detected in all blood samples tested (range: 0.28-3.79 microg/L, median: 0.66 microg/L). Time-course experiments with trichloronitromethane- and tribromonitromethane-spiked blood showed that nitromethane was the major product formed (1 nmole tribromonitromethane formed 0.59 nmole of nitromethane, whereas 1 nmole trichloronitromethane formed 0.77 nmole nitromethane). Nitromethane may form endogenously from peroxynitrite: nitromethane concentrations increased proportionately in blood samples spiked with peroxynitrite. Blood nitromethane can be a biomarker of exposure to both nitromethane and halonitromethanes. This sensitive, accurate, and precise analytical method can be used to determine baseline blood nitromethane level in the general population. It can also be used to study the health impact from exposure to nitromethane and halonitromethanes in occupational environments and to assess trichloronitromethane (chloropicrin) exposure in chemical terrorism investigations.

Quantification of fuel oxygenate ethers in human blood using solid-phase microextraction coupled with gas chromatography-high-resolution mass spectrometry.

Widespread use of fuel oxygenates, coupled with their high water solubility and slow degradation rate, have led to an increase in the potential for human exposure. We developed an accurate, precise, sensitive, and high-throughput analytical method to simultaneously quantify trace levels (low parts-per-trillion) of four fuel oxygenates in human blood: methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), di-isopropyl ether (DIPE), and tert-amyl methyl ether (TAME). The analytes were extracted from the head space above human blood samples, using solid-phase microextraction, desorbed into the heated injector, and chromatographically resolved by capillary gas chromatography. Analytes were detected by high-resolution mass spectrometry with multiple ion monitoring, and quantified against known standard levels by use of stable isotope-labeled internal standards for recovery correction. The low limits of detection (0.6 ng/L) allowed for measurement of MTBE, ETBE, DIPE, and TAME in parts-per-trillion levels with excellent precision (coefficient of variation ranging from 1.7 to 5.4%) and accuracy (96-100%). This method provides a means to assess fuel oxygenate exposure and study the potential relationship between exposure and adverse health outcomes.

Early health assessment of refugees.

This is the first in a series of articles looking at refugee health in Australian general practice. Each year approximately 13,000 refugees settle in Australia, mostly from countries with minimal public and personal health resources. They may present in a very different manner to the rest of the population and are at risk of unfamiliar and complex illnesses. Their health care can be difficult and time consuming and the general practitioners who supply this care need support, guidance and adequate remuneration. The new Medicare Benefits Schedule item numbers 714 and 716 are an acknowledgment by the Australian government of these concerns of community GPs who are seeing refugees for their initial health assessments. This article discusses, in the context of the new item number, some of the broader issues that are important when seeing refugees for the first time.

Measurement of trihalomethanes and methyl tert-butyl ether in whole blood using gas chromatography with high-resolution mass spectrometry.

The prevalence of disinfection by-products in drinking water supplies has raised concerns about possible adverse health effects from chronic exposure to these compounds. To support studies exploring the relation between exposure to trihalomethanes (THMs) and adverse health effects, an automated analytical method was developed using capillary gas chromatography (GC) and high-resolution mass spectrometry (MS) with selected ion mass detection and isotope-dilution techniques. This method quantified trace levels of THMs (including chloroform, bromodichloromethane, dibromochloromethane, and bromoform) and methyl tert-butyl ether (MTBE) in human blood. Analyte responses were adequate for measuring background levels after extraction of these volatile organic compounds with either purge-and-trap extraction or headspace solid-phase microextraction (SPME). The SPME method was chosen because of its ease of use and higher throughput. Detection limits for the SPME GC-MS method ranged from 0.3 to 2.4 ng/L, with linear ranges of three orders of magnitude. This method proved adequate for measuring the THMs and MTBE in most blood samples tested from a diverse U.S. reference population.