Variability of albumin adducts of 1,4-benzoquinone, a toxic metabolite of benzene, in human volunteers

A putative haematotoxic and leukaemogenic metabolite of benzene, 1,4-benzoquinone (1,4-BQ), reacts rapidly with macromolecules. The authors previously characterized levels of the albumin (Alb) adduct (1,4-BQ-Alb) of this reactive species in populations of workers exposed to benzene. Since high levels of 1,4-BQ-Alb were also measured in unexposed workers from those investigations, the current study was initiated to determine potential sources of 1,4-BQ in the general population. A single blood sample was collected from 191 healthy subjects from the Research Triangle area, NC, USA, to determine the baseline 1,4-BQ-Alb levels and contributing sources. The median 1,4-BQ-Alb at baseline was 550 pmol g^-1 Alb (interquartile range 435-814 pmol g^-1). A second blood sample was collected approximately 3 months later from a subgroup of 33 subjects to estimate the within- and between-person variation in 1,4-BQ-Alb. Standardized questionnaires were administered to collect information about demographic, dietary and lifestyle factors. Multiple linear regression models identified several significant contributors to 1,4-BQ-Alb levels, including gender, body mass index (BMI), the gender-BMI interaction, automobile refuelling, smoking status, and consumption of fruit and the artificial sweetener, aspartame. The authors predicted that these background levels of 1,4-BQ-Alb were equivalent to occupational exposures between 1 and 3 parts per million of benzene. Mixed effects linear models indicated that the random variation in adduct levels was about equally divided between and within subjects. The observations indicate that levels of 1,4-BQ-Alb cover a wide range in the general population, and they support the hypotheses that demographic, diet and lifestyle factors are contributing sources.     

外泌体分泌在1,4-苯醌诱导的HL-60细胞凋亡中起保护作用

慢性苯暴露损害造血系统,可引起再生障碍性贫血,甚至白血病。外泌体(exosomes)是细胞分泌的纳米级膜泡,在许多生理和病理过程中发挥重要作用。然而,苯及其代谢产物对外泌体分泌的影响仍不清楚。本研究旨在观察苯的活性代谢产物1,4-苯醌(1,4-benzoquinone,1,4-BQ)能否引起人早幼粒白血病细胞HL-60外泌体分泌量的变化以及外泌体释放在1,4-BQ诱导的细胞凋亡中的作用。应用不同浓度1,4-BQ处理细胞24 h,超高速离心法提取细胞培养基中的外泌体,结果发现1,4-BQ能促进外泌体分泌,呈剂量反应关系。进一步应用外泌体抑制剂GW4869抑制外泌体分泌,流式细胞仪检测细胞凋亡率、蛋白质免疫印迹法检测抑凋亡蛋白质Bcl-2、凋亡通路关键蛋白质cleaved caspase-9和cleaved caspase-3的表达,探讨外泌体分泌对1,4-BQ所致细胞凋亡的影响。结果显示:与对照组相比,1,4-BQ单独处理组的凋亡率、Bcl-2、cleaved caspase-9和cleaved caspase-3的表达均显著增高(P<0.05),而1,4-BQ+GW4869组的凋亡率及凋亡相关蛋白质的表达均显著高于1,4-BQ单独处理组(P<0.05),表明抑制外泌体分泌可增加1,4-BQ诱导的细胞凋亡。综上表明,1,4-BQ能促进外泌体分泌,并在1,4-BQ诱导的细胞凋亡中起保护作用。本研究为了解苯的毒性效应和毒性机制提供了新的实验证据。     

Non-linear production of benzene oxide-albumin adducts with human exposure to benzene

Benzene is initially metabolized to benzene oxide, which either undergoes further metabolism or reacts with macromolecules including proteins. Previously reported levels of benzene oxide-albumin adducts (BO-Alb) are analyzed from 30 workers exposed to 0.2-302 ppm benzene and 43 controls from Shanghai, China. Although both exposed workers and controls had significant levels of BO-Alb in their blood, exposed subjects' adduct levels (GM=378 pmol/g protein) were much greater than those of controls (GM=115 pmol/g protein). When the natural logarithm of the BO-Alb level was regressed upon the natural logarithm of exposure among the 30 exposed subjects, a strong effect of benzene exposure was observed (R(2)=0.612; p<0.0001). Because the slope of the relationship between BO-Alb and benzene exposure was significantly less than one in log-space, we infer that production of benzene oxide was less than proportional to benzene exposure. Since benzene is a substrate for CYP2E1, these results are consistent with saturation of CYP450 metabolism. They indicate that deviations from linear metabolism began at or below benzene exposures of 10 ppm and that pronounced saturation was apparent at 40-50 ppm. To our knowledge, this is the first study to investigate the linearity of human metabolism of a carcinogen based upon protein adducts.     

Investigation of the cumulative tissue doses of naphthoquinones in human serum using protein adducts as biomarker of exposure

Both 1,2-naphthoquinone (1,2-NPQ) and 1,4-naphthoquinone (1,4-NPQ) are reactive metabolites of naphthalene that are thought to be responsible for the naphthalene-induced cytotoxicity and genotoxicity. The aim of this study was to investigate the cumulative tissue dose of 1,2-NPQ and 1,4-NPQ in human serum derived from blood donors in Taiwan via measurements of albumin adducts by a methodology, which employs trifluoroacetic acid anhydride and methanesulfonic acid to selectively cleave cysteinyl adducts on proteins. Both 1,2-NPQ and 1,4-NPQ adducts were detected in all male and female subjects (n = 22). The median levels of 1,2-NPQ adduct in human subjects were estimated to be 268 (range 139-857) and 203 (range 128-1352) (pmol/g) in male (n = 11) and female (n = 11) subjects, respectively. In contrast, the median levels of 1,4-NPQ adduct were estimated to be 45.0 (range 22.0-117) and 38.9 (range 21.5-172) (pmol/g) in male and female subjects, respectively. We noticed that levels of 1,2-NPQ adduct were significantly correlated with those of 1,4-NPQ adduct (correlation coefficient r = 0.643, p < 0.01). Results from in vitro experiments confirmed that the production of naphthoquinones-derived adducts on serum albumin increased with increased concentration of naphthoquinones (0-100 μM). Linear relationships were observed over the range of concentration. Time-course experiments suggested that both 1,2-NPQ and 1,4-NPQ-derived adducts rapidly reached maximum values at 10 min mark and remained constant thereafter. The reaction rate constant analyses indicated that the second-order rate constants, representing in vitro reactions between naphthoquinones and cysteine residues of serum albumin, were estimated to be 0.0044/0.0002 L(g protein)⁻¹ h⁻¹, respectively. Overall, the cumulative tissue doses of 1,4-NPQ (217-316 nM h) in male and female subjects were ∼3-fold greater than those of 1,2-NPQ (76-98 nM h) in the study population. The initial concentrations of serum 1,2-NPQ and 1,4-NPQ in the study population were estimated to be between 145-188 and 807-1175 nM, respectively. We conclude that the relatively large amounts of naphthoquinones present in human serum may point to toxicological consequences.     

Exposure to naphthalene induces naphthyl-keratin adducts in human epidermis in vitro and in vivo

We observed naphthyl-keratin adducts and dose-related metabolic enzyme induction at the mRNA level in reconstructed human epidermis in vitro after exposure to naphthalene. Immunofluorescence detection of 2-naphthyl-keratin-1 adducts confirmed the metabolism of naphthalene and adduction of keratin. We also observed naphthyl-keratin adducts in dermal tape-strip samples collected from naphthalene-exposed workers at levels ranging from 0.004 to 6.104 pmol adduct µg^?1 keratin. We have demonstrated the ability of the human skin to metabolize naphthalene and to form naphthyl-keratin adducts both in vitro and in vivo. The results indicate the potential use of keratin adducts as biomarkers of dermal exposure.     

A note on urinary trans,trans-muconic acid level among Thai press workers

Benzene is a common toxic volatile substance associated with many industrial processes. Benzene exposure is of particular concern because recent research indicates that it can result in chronic toxicity and thousands of workers in industrial plants experience ongoing exposure. Therefore, the determination and control of benzene exposure among at-risk workers is very important. Urinary trans,trans-muconic acid (ttMA) determination is a helpful test for monitoring groups of at-risk workers for exposure to benzene. In this study, 103 urine samples were obtained from 60 controls and 43 occupational exposed press workers in a press factory in Bangkok. All samples were analysed for ttMA using a previously reported method. The average urinary ttMA levels for the control and exposed groups were 0.08±0.03 mg g^?1 creatinine and 0.56±0.65 mg g^?1 creatinine, respectively. Significantly higher urinary ttMA levels were observed among the press workers (p=0.03). The introduction of public health policies concerning the prevention of exposure to benzene among at-risk workers is recommended, and more widespread use of biological monitoring for the assessment and control of occupational exposure to industrial chemicals is encouraged.     

Development of a competitive immunoassay for the determination of N-(2-hydroxyethyl)valine adducts in human haemoglobin and its application in biological monitoring

Ethylene oxide (EO) is an important industrial compound and a directly acting mutagen. Human exposure to it can be monitored by the determination of haemoglobin (Hb) adducts. An immunoassay that quantifies the N-terminal adduct N-(2-hydroxyethyl)valine in whole blood was developed and its potential usefulness as a tool for biologically monitoring occupational exposure demonstrated. Analytical reliability was confirmed in a comparative study with gas chromatography-mass spectrometry (range 0.040–589?nmol?g^?1 Hb, correlation coefficient 0.98, n=10). The assay was configured as a competitive enzyme-linked immunosorbent assay to facilitate the rapid throughput of samples. The assay uses a whole blood matrix and has a working range of 10–10?000 pmol N-(2-hydroxethyl)valine?g^?1 Hb. The assay does not appear to be affected by structurally similar metabolites and has been used to determine adducts in human blood samples. The first results from potentially exposed workers indicate the assay might be a powerful tool for the routine occupational biomonitoring of EO exposure.     

Increased levels of urinary biomarkers of lipid peroxidation products among workers occupationally exposed to diesel engine exhaust

Diesel engine exhaust (DEE) was found to induce lipid peroxidation (LPO) in animal exposure studies. LPO is a class of oxidative stress and can be reflected by detecting the levels of its production, such as malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), and etheno-DNA adducts including 1,N⁶-etheno-2′-deoxyadenosine (?dA) and 3,N⁴-etheno-2′-deoxycytidine (?dC). However, the impact of DEE exposure on LPO has not been explored in humans. In this study, we evaluated urinary MDA, 4-HNE, ?dA, and ?dC levels as biomarkers of LPO among 108 workers with exclusive exposure to DEE and 109 non-DEE-exposed workers. Results showed that increased levels of urinary MDA and ?dA were observed in subjects occupationally exposed to DEE before and after age, body mass index (BMI), smoking status, and alcohol use were adjusted (all p?p?p?相似文献   

Correlation between pentosidine and endothelin-1 in subjects undergoing chronic hemodialysis.

Advanced glycation end-products (AGEs), which accumulate in the blood and tissues of patients with chronic renal failure (CRF) undergoing chronic hemodialysis, play an important role in the pathogenesis of uremic complications. Endothelin 1 (ET1), a 21-amino acid peptide with vasoconstricting and mitogenic properties, is an important factor in the endothelial dysfunction occurring in uremia. The circulating levels of both AGEs and ET1 have been reported to be increased in chronic renal failure. In the present study we evaluated the possible relationship between pentosidine and ET1 plasma levels in CRF patients undergoing chronic hemodialysis treatment. The plasma concentrations of "free" and bound pentosidine (HPLC methods) and endothelin-1 (RIA method) were measured before the hemodialysis session in 40 nondiabetic CRF patients (22 males and 18 females; 54+/-3 years) on chronic hemodialysis for at least 1 year. Forty age- and sex-matched normal subjects served as a control group. In hemodialyzed patients, the overall pentosidine residues and pentosidine-free adduct plus pentosidine-free adduct bound reversibly to protein levels (24.9+/-2.04 pmol/mg protein and 110.5+/-5.9 pmol/ml, respectively) were significantly higher than those recorded in normal subjects (2.0+/-0.2 pmol/mg protein and 0.7+/-0.2 pmol/ml, respectively ). Endothelin-1 was also significantly (p<0.01) increased in CRF patients (10.6+/-0.4 pmol/ml in CRF patients and 2.7+/-0.3 pmol/ml in normal subjects). A significant positive correlation (p<0.01) was seen between "total" pentosidine (pentosidine residues and pentosidine-free adduct plus pentosidine-free adduct bound reversibly to protein) levels and endothelin-1 plasma values. The correlation between pentosidine and endothelin-1 provides further evidence that some AGEs exert a detrimental effect on the vascular endothelium, thereby contributing to the hypertension and other cardiovascular damage seen in CRF patients.     

Quinone-induced inhibition of urease: elucidation of its mechanisms by probing thiol groups of the enzyme

In this work we studied the reaction of four quinones, 1,4-benzoquinone (1,4-BQ), 2,5-dimethyl-1,4-benzoquinone (2,5-DM-1,4-BQ), tetrachloro-1,4-benzoquinone (TC-1,4-BQ) and 1,4-naphthoquinone (1,4-NQ) with jack bean urease in phosphate buffer, pH 7.8. The enzyme was allowed to react with different concentrations of the quinones during different incubation times in aerobic conditions. Upon incubation the samples had their residual activities assayed and their thiol content titrated. The titration carried out with use of 5,5'-di-thiobis(2-nitrobenzoic) acid was done to examine the involvement of urease thiol groups in the quinone-induced inhibition. The quinones under investigation showed two distinct patterns of behaviour, one by 1,4-BQ, 2,5-DM-1,4-BQ and TC-1,4-BQ, and the other by 1,4-NQ. The former consisted of a concentration-dependent inactivation of urease where the enzyme-inhibitor equilibrium was achieved in no longer than 10min, and of the residual activity of the enzyme being linearly correlated with the number of modified thiols in urease. We concluded that arylation of the thiols in urease by these quinones resulting in conformational changes in the enzyme molecule is responsible for the inhibition. The other pattern of behaviour observed for 1,4-NQ consisted of time- and concentration-dependent inactivation of urease with a nonlinear residual activity-modified thiols dependence. This suggests that in 1,4-NQ inhibition, in addition to the arylation of thiols, operative are other reactions, most likely oxidations of thiols provoked by 1,4-NQ-catalyzed redox cycling. In terms of the inhibitory strength, the quinones studied formed a series: 1,4-NQ approximately 2,5-DM-1,4-BQ<1,4-BQ相似文献   

BTEX Exposures among Automobile Mechanics and Painters and Their Associated Health Risks

We measured the concentrations of benzene, toluene, ethylbenzene, and xylenes (BTEX) in the ambient air of automobile repair garages in Montreal, Canada, using the direct atmospheric pressure chemical ionization-tandem mass spectrometry (APCI-MS/MS) method. Among all the air samples analyzed, toluene was the most abundant BTEX-species (127–1101 μg/m³) followed by xylenes (50–323 μg/m³), ethylbenzene (11–65 μg/m³), and benzene (9.2–23 μg/m³). BTEX levels where ventilation was controlled simultaneously by both mechanical and natural systems were significantly less than levels at garages where only natural ventilation was used. Results suggest that multiple sources contribute to the occupational exposure of automobile mechanics and painters to the BTEX. Owing to the toxic effects of these chemicals, both chronic non-cancer hazard and integrated lifetime cancer risk due to the exposure of this occupational group were assessed. The levels of the BTEX measured at all the garages were less than the established limits for occupational exposure; still, benzene levels pose a potential cancer risk for the workers. At the prevailing levels of BTEX, they may not cause any chronic non-cancer problems for the workers.     

Characterization of pyranose oxidase variants for bioelectrocatalytic applications

Pyranose oxidase (POx) catalyzes the oxidation of d-glucose to 2-ketoglucose with concurrent reduction of oxygen to H₂O₂. POx from Trametes ochracea (ToPOx) is known to react with alternative electron acceptors including 1,4-benzoquinone (1,4-BQ), 2,6-dichlorophenol indophenol (DCPIP), and the ferrocenium ion. In this study, enzyme variants with improved electron acceptor turnover and reduced oxygen turnover were characterized as potential anode biocatalysts. Pre-steady-state kinetics of the oxidative half-reaction of ToPOx variants T166R, Q448H, L545C, and L547R with these alternative electron acceptors were evaluated using stopped-flow spectrophotometry. Higher kinetic constants were observed as compared to the wild-type ToPOx for some of the variants. Subsequently, the variants were immobilized on glassy carbon electrodes. Cyclic voltammetry measurements were performed to measure the electrochemical responses of these variants with glucose as substrate in the presence of 1,4-BQ, DCPIP, or ferrocene methanol as redox mediators. High catalytic efficiencies (I_max^app/K_M^app) compared to the wild-type POx proved the potential of these variants for future bioelectrocatalytic applications, in biosensors or biofuel cells. Among the variants, L545C showed the most desirable properties as determined kinetically and electrochemically.     

Development of a competitive immunoassay for the determination of N-(2-hydroxypropyl)valine adducts in human haemoglobin and its application in biological monitoring

Abstract

Propylene oxide (PO) is an important industrial compound and a directly acting mutagen. Human exposure to PO can be monitored by the determination of haemoglobin adducts. An immunoassay that quantifies the N-terminal adduct N-(2-hydroxypropyl)valine in whole haemoglobin was developed and its potential usefulness as a tool for biologically monitoring occupational exposure was demonstrated. Analytical reliability was confirmed in a comparative study with GC-MS (range 3.7–992 nmol g^?1 haemoglobin (Hb), correlation coefficient 0.99, n=10). The assay has been configured as a competitive enzyme-linked immunosorbent assay to facilitate the rapid throughput of samples. The assay employs a whole blood matrix and has a working range of 2–250 pmol g^?1 Hb. It does not appear to be affected by structurally similar metabolites and has been used to determine adducts in human blood samples. The first results in potentially exposed workers indicate the assay's high potential usefulness in routine occupational biomonitoring of exposure to PO.     

Diurnal fluctuations of endogenous IAA content in aralia leaves

Diurnal variations in endogenous IAA levels inFatsia japonica leaves, maintaining constant other external factors such as temperature and relative humidity, were studied. Plants were cultivated in a growth chamber (20 °C, 75 % RH, 16 h photoperiod, 400 µmol m^-2 s^-1 PAR). IAA analyses were carried out by analytical IP-HPLC with on-line spectrofluorimetry. Rhythmic variation of endogenous IAA levels was found. At the onset of the light period the IAA concentration dropped very rapidly from 1070 pmol g^-1 (fr.m.) to 144 pmol g^-1 (fr.m.). This concentration was nearly constant throughout the entire light period. During the subsequent dark period the IAA levels increased again to about 1000 pmol g^-1 (fr.m.) at the end of the dark phase. These results were not confirmed in open field conditions where many other external factors probably influence the endogenous IAA content.     

ADIPOQ Polymorphisms,Monounsaturated Fatty Acids,and Obesity Risk: The GOLDN Study

Serum adiponectin levels have been positively associated with insulin sensitivity and are decreased in type 2 diabetes (T2D) and obesity. Genetic and environmental factors influence serum adiponectin and may contribute to risk of metabolic syndrome and T2D. Therefore, we investigated the effect of ADIPOQ single‐nucleotide polymorphisms (SNPs), ?11377C>G and ?11391G>A, on metabolic‐related traits, and their modulation by dietary fat in white Americans. Data were collected from 1,083 subjects participating in the Genetics of Lipid Lowering Drugs and Diet Network study. Mean serum adiponectin concentration was higher for carriers of the ?11391A allele (P = 0.001) but lower for the ?11377G allele carriers (P = 0.017). Moreover, we found a significant association with obesity traits for the ?11391G>A SNP. Carriers of the ?11391A allele had significantly lower weight (P = 0.029), BMI (P = 0.019), waist (P = 0.003), and hip circumferences (P = 0.004) compared to noncarriers. Interestingly, the associations of the ?11391G>A with BMI and obesity risk were modified by monounsaturated fatty acids (MUFAs) intake (P‐interaction = 0.021 and 0.034 for BMI and obesity risk, respectively). In subjects with MUFA intake above the median (≥13% of energy intake), ?11391A carriers had lower BMI (27.1 kg/m² for GA+AA vs. 29.1 kg/m² for GG, P = 0.002) and decreased obesity risk (odds ratio for ?11391A = 0.52, 95% confidence interval (CI); 0.28–0.96; P = 0.031). However, we did not detect genotype‐related differences for BMI or obesity in subjects with MUFA intake <13%. Our findings support a significant association between the ?11391G>A SNPs and obesity‐related traits and the potential to moderate such effects using dietary modification.     

Effect of hippuric acid on the gaschromatographic retention of S-phenylmercapturic acid

S-phenylmercapturic acid (PMA) is one specific urinary biomarker of low-level benzene exposure. It is used for biological monitoring of benzene-exposed workers in the petrochemical industry and normally ranges from non-measurable to 10 microg/l levels in non-exposed non-smoking subjects. Benzene-exposure caused by workplace or lifestyle sources is frequently accompanied by toluene exposure, which can cause the occurrence of high levels (from 10 mg/l to more than 2000 mg/l) of hippuric acid (HA) in urine. Both solvents are toxic, and benzene is classified as a human carcinogen. The biological monitoring of benzene and toluene is therefore required for preventive care of exposed workers health. In this study a GC-MS method was adopted for measuring urinary PMA, which involved liquid-liquid extraction (LLE) with ethyl acetate from acidified urine and esterification with 0.5 N hydrochloric acid in methanol. The method evidenced a GC effect in a conventional HP-5 (30 m x 0.25 mm i.d., 0.25 microm film-thickness) methyl-phenylsilicone capillary column produced by HA on PMA. The results demonstrate that HA at concentrations as low as 250 mg/l can delay the elution of PMA and labelled internal standard from the column. The recognition and discussion of this particular GC phase soaking effect may be of help for those who are occupied in the determination of PMA and of urinary acidic metabolites by GC.     

Prevalence of Obesity and Associated Risk Factors in a Turkish Population (Trabzon City,Turkey)

Objective: To estimate the prevalence of overweight and obesity (general and central) in the Trabzon Region and its associations with demographic factors (age, sex, marital status, reproductive history in women, and level of education), socioeconomic factors (household income and occupation), family history of selected medical conditions (diabetes, hypertension, and obesity), lifestyle factors (smoking habits, physical activity, and alcohol consumption), and hypertension in the adult population. Research Methods and Procedures: A sample of households was systematically selected from the central province of Trabzon and its five towns, namely, Sürmene, Vakfikebir, Maçka, Hayrat, and Tonya. A total of 5016 subjects (2728 women and 2288 men) were included in the study. Individuals more than 20 years old were selected from their family health cards. Demographic factors, socioeconomic factors, family history of selected medical conditions, and lifestyle factors were obtained for all participants. Systolic blood pressure and diastolic blood pressure levels were measured for all subjects. Study procedures were carried out in the local health centers in each town over an 8‐month period. Obesity was defined as BMI ≥ 30 kg/m² and overweight as BMI = 25.0 to 29.9 kg/m². Results: The prevalence of obesity was 23.5%: 29.4% in women and 16.5% in men. The combined prevalence of both overweight and obesity was 60.3%. The prevalence of abdominal obesity was 29.4%: 38.9% among women and 18.1% among men. The prevalence of obesity increased with age, being highest in the 60‐ to 69‐year‐old age group (40.8%) but lower again in the 70+ age group. Obesity was associated positively with marital status, parity, cessation of cigarette smoking, alcohol consumption, and household income and inversely with level of education, cigarette use, and physical activity. Also, obesity was associated positively with hypertension. Discussion: In the Trabzon Region, 60.3% of the adult population presents with some excess weight. Obesity is a major public health problem that requires generalized interventions to prevent it among the adult population.     

Lower Inter-Partum Interval and Unhealthy Life-Style Factors Are Inversely Associated with n-3 Essential Fatty Acids Changes during Pregnancy: A Prospective Cohort with Brazilian Women

Objective

To analyze serum fatty acids concentrations during healthy pregnancy and evaluate whether socioeconomic, demographic, obstetric, nutritional, anthropometric and lifestyle factors are associated with their longitudinal changes.

Study design

A prospective cohort of 225 pregnant women was followed in the 5^th–13^th, 20^th–26^th and 30^th–36^th weeks of gestation. Serum samples were collected in each trimester of pregnancy and analyzed to determine the fatty acids composition using a high-throughput robotic direct methylation method coupled with fast gas-liquid chromatography. The independent variables comprised the subjects’ socioeconomic and demographic status, obstetric history, early pregnancy body mass index (BMI), dietary and lifestyle parameters. Analyses were performed using linear mixed-effects models.

Results

The overall absolute concentrations of fatty acids increased from the 1^st to the 2^nd trimester and slightly increased from the 2^nd to the 3^rd trimester. Early pregnancy BMI, inter-partum interval and weekly fish intake were the factors associated with changes in eicosapentaenoic + docosahexaenoic acids (EPA+DHA) and total n-3 polyunsaturated fatty acids (PUFAs). Early pregnancy BMI, age and monthly per-capita income were inversely associated with the changes in the n-6/n-3 ratio. Alcohol consumption was positively associated with the n-6/n-3 ratio.

Conclusion

Early pregnancy BMI was positively associated with EPA+DHA and total n-3 PUFAs, while presenting a reduced weekly fish intake and a lower inter-partum interval were associated with lower levels of n-3 PUFAs. A lower per-capita family income and a drinking habit were factors that were positively associated with a higher n-6/n-3 ratio.     

Biological monitoring among benzene-exposed workers in Bangalore city,India

Abstract

Environmental and biological monitoring was carried out in the winter season of 2004 for 30 gasoline station workers (study subjects) and 30 office workers (controls) of Bangalore city, India. Personal air sampling was carried out in the breathing zone of workers using an Anasorb CSC sorbent tube (SKC 226-01) fitted to the low-flow personal samplers (PCXR4 and pocket pump Model No. 210-1002) at a flow rate of 200 ml min^?1 during the shift work of 8 h. The benzene content adsorbed in the sorbent tube (SKC 226-01) was desorbed with 1 ml of benzene-free carbon disulfide on a developing vibrator and later analysed by Trace GC fitted with MXT-624 column and flame ionization detector. The mean time weighted average benzene concentration found among study and controls was 1.10±1.08 and 0.070±0.035 mg m^?3, respectively. Biological monitoring for benzene exposure was performed by measuring trans,trans muconic acid (t,t-MA) in the end shift urine samples using HPLC-UV technique. End-shift urine samples (1 ml) were adjusted to pH 7–9 with phosphate buffer pH 7.4 passed through the preconditioned Q-SAX anion-exchange cartridge and the (t,t-MA) is extracted with 10% acetic acid and later analysed by HPLC-UV detection The mean t,t-MA found among study and controls were 563.16±281.81 and 266.88±110.65 µg g^?1 creatinine. About 50% of the study subjects (15) have higher t,t-MA values than the biological exposure index of the American Conference of Government Industrial Hygienist (ACGIH). Correlation is significant at 5% level (p<0.05) between personal air benzene concentration and urinary t,t-MA in the study group. Based on these findings, the t,t-MA can be used as a biomarker for benzene exposure.     

Hormone Profiling by LC-QToF-MS/MS in Dormant <Emphasis Type="Italic">Macadamia integrifolia</Emphasis>: Correlations with Abnormal Vertical Growth

A method for analyzing multiple plant hormone groups in small samples with a complex matrix was developed to initiate a study of the physiology of abnormal vertical growth (AVG) in Macadamia integrifolia (cv. HAES344). Cytokinins (CKs), gibberellins (GAs), abscisic acid (ABA), and auxins were detected in xylem sap and apical and lateral buds using high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (LC-QToF-MS/MS). The extraction method separated compounds with high sensitivity in positive (CKs) and negative (ABA, auxins, GAs) modes of QToF-MS/MS. CK profiles differed in xylem sap and apical and lateral buds irrespective of AVG symptoms. Trans-zeatin riboside (t-ZR) was dominant in sap of normal and AVG trees (∼4 and 6 pmol g⁻¹ FW, respectively). In apical buds isopentenyl adenine (iP) (∼30 pmol g⁻¹ FW) was the most abundant CK, and in lateral buds trans-zeatin (t-Z) (22–24 pmol g⁻¹ FW) and iP (24–30 pmol g⁻¹ FW) were the most abundant. t-Z levels of AVG trees were higher in apical buds (13.88 vs. 6.6 pmol g⁻¹ FW, p < 0.05) and lower in sap (0.16 vs. 0.51 pmol ml⁻¹, p < 0.005) compared to normal trees. ABA in lateral buds was 1.9 times higher (p < 0.001) in AVG. IAA was below quantification, whereas indole-3-butyric acid (IBA) was consistently present. GA₇ was the dominant GA in apical and lateral buds of all trees (100–150 pmol g⁻¹ FW). GA_{3, 4, & 9} were consistently present at low concentrations (<12 pmol g⁻¹ FW) in buds. GAs_{1, 3, & 9} were detected in xylem sap at low concentrations (<0.5 pmol g⁻¹ FW). Differences in sap amino acids (AA) were also assessed. In sap from AVG trees, asparagine and glutamine increased significantly (p < 0.05) in their contribution to total AA. Potential AVG hormone correlations are discussed.