An untargeted metabolomics method for archived newborn dried blood spots in epidemiologic studies

INTRODUCTION

For pediatric diseases like childhood leukemia, a short latency period points to in-utero exposures as potentially important risk factors. Untargeted metabolomics of small molecules in archived newborn dried blood spots (DBS) offers an avenue for discovering early-life exposures that contribute to disease risks.

OBJECTIVES

The purpose of this study was to develop a quantitative method for untargeted analysis of archived newborn DBS for use in an epidemiological study (California Childhood Leukemia Study, CCLS).

METHODS

Using experimental DBS from the blood of an adult volunteer, we optimized extraction of small molecules and integrated measurement of potassium as a proxy for blood hematocrit. We then applied this extraction method to 4.7-mm punches from 106 control DBS samples from the CCLS. Sample extracts were analyzed with liquid chromatography high resolution mass spectrometry (LC-HRMS) and an untargeted workflow was used to screen for metabolites that discriminate population characteristics such as sex, ethnicity, and birth weight.

RESULTS

Thousands of small molecules were measured in extracts of archived DBS. Normalizing for potassium levels removed variability related to varying hematocrit across DBS punches. Of the roughly 1,000 prevalent small molecules that were tested, multivariate linear regression detected significant associations with ethnicity (3 metabolites) and birth weight (15 metabolites) after adjusting for multiple testing.

CONCLUSIONS

This untargeted workflow can be used for analysis of small molecules in archived DBS to discover novel biomarkers, to provide insights into the initiation and progression of diseases, and to provide guidance for disease prevention.

Benzene exposure near the U.S. permissible limit is associated with sperm aneuploidy

BACKGROUND

Benzene is a common industrial chemical known to induce leukemia and other blood disorders, as well as aneuploidy, in both human blood cells and sperm at exposures > 10 ppm. Recent reports have identified health effects at exposure levels < 1 ppm, the permissible exposure limit (PEL; 8 hr) set by the U.S. Occupational Safety and Health Administration.

OBJECTIVE

We investigated whether occupational exposures to benzene near 1 ppm induce aneuploidy in sperm.

METHODS

We used multicolor fluorescence in situ hybridization to measure the incidence of sperm with numerical abnormalities of chromosomes X, Y, and 21 among 33 benzene-exposed men and 33 unexposed men from Chinese factories. Individual exposures were assessed using personal air monitoring and urinary concentrations of benzene and trans,trans-muconic acid (E,E-MA). Air benzene concentrations were not detectable in unexposed men; in exposed men, concentrations ranged from below the detection limit to 24 ppm (median, 2.9 ppm), with 27% of exposed men (n = 9) having concentrations of <or= 1 ppm. Exposed men were categorized into low and high groups based on urinary E,E-MA (median concentrations of 1.9 and 14.4 mg/L, respectively; median air benzene of 1 and 7.7 ppm, respectively), and aneuploidy frequencies were compared with those of unexposed men.

RESULTS

Sperm aneuploidy increased across low- and high-exposed groups for disomy X [incidence rate ratio (IRR) = 2.0; 95% confidence interval (CI), 1.1-3.4; and IRR = 2.8; 95% CI, 1.5-4.9, respectively], and for overall hyperhaploidy for the three chromosomes investigated (IRR = 1.6; 95% CI, 1.0-2.4; and IRR = 2.3; 95% CI, 1.5-3.6, respectively). We also found elevated disomy X and hyperhaploidy in the nine men exposed to <or= 1 ppm benzene compared with unexposed men (IRR = 1.8; 95% CI, 1.1-3.0; and IRR = 2.0; 95% CI, 1.1-3.9, respectively).

CONCLUSIONS

Benzene appeared to increase the frequencies of aneuploid sperm for chromosomes associated with chromosomal abnormality syndromes in human offspring, even in men whose air benzene exposure was at or below the U.S. permissible exposure limit.

Effectiveness of a urinary control insert in the management of stress urinary incontinence: early results of a multicenter study

OBJECTIVES

The purpose of this study was to test the safety and effectiveness of a urethral insert for managing stress or mixed urinary incontinence.

METHODS

We performed a prospective, multicenter study of 135 female patients who were treated for 4 months with the Reliance Urinary Control Insert. The effectiveness of the insert was measured objectively at the time of first use and after 4 months' use by standardized pad weight studies. Insert effectiveness was also measured by reports of symptom improvement during patient interviews and on patient diaries. Urine microscopy and culture were obtained monthly; cystoscopy and urodynamics were conducted at study entry and at 4 months.

RESULTS

Significant improvement in involuntary urine loss was observed. Objective measurement of urine loss revealed that 80% of the patients were completely dry, and 95% of the patients achieved greater than an 80% decrease in urine loss. In addition, patients' perceptions of acceptability, incontinence symptom improvement, ease of learning, comfort, and time to habituation also showed improvements. Untoward events reported during the study included hematuria, bacteriuria, and bladder irritation. These events did not require significant medical intervention and did not result in any long-term clinical sequelae.

CONCLUSIONS

These preliminary results indicate that the Reliance Urinary Control Insert may be a safe, effective, and well-tolerated alternative to other available methods for the management of stress or mixed incontinence in women. Additional long-term follow-up will be required to substantiate this conclusion.

Long-term Safety and Efficacy of Tapentadol Extended Release Following up to 2 Years of Treatment in Patients With Moderate to Severe, Chronic Pain: Results of an Open-label Extension Trial

PURPOSE

Tapentadol extended release (ER) has demonstrated efficacy and safety for the management of moderate to severe, chronic pain in adults. This study evaluated the long-term safety and tolerability of tapentadol ER in patients with chronic osteoarthritis or low back pain.

METHODS

Patients were enrolled in this 1-year, open-label extension study after completing one of two 15-week, placebo-controlled studies of tapentadol ER and oxycodone controlled release (CR) for osteoarthritis knee pain (NCT00421928) or low back pain (NCT00449176), a 7-week crossover study between tapentadol immediate release and tapentadol ER for low back pain (NCT00594516), or a 1-year safety study of tapentadol ER and oxycodone CR for osteoarthritis or low back pain (NCT00361504). After titrating the drug to an optimal dose, patients received tapentadol ER (100-250 mg BID) for up to 1 year (after finishing treatment in the preceding studies); patients who were previously treated with tapentadol ER in the 1-year safety study received tapentadol ER continuously for up to 2 years in total.

FINDINGS

Of the 1,154 patients in the safety population, 82.7% were aged >65 years and 57.9% were female; 50.1% had mild baseline pain intensity. Mean (SD) pain intensity scores (11-point numerical rating scale) were 3.9 (2.38) at baseline (end of preceding study) and 3.7 (2.42) at end point, indicating that pain relief was maintained during the extension study. Improvements in measures of quality of life (eg, EuroQol-5 Dimension and the 36-item Short Form Health Survey [SF-36]) health status questionnaires) achieved during the preceding studies were maintained during the open-label extension study. Tapentadol ER was associated with a safety and tolerability profile comparable to that observed in the preceding studies. The most common treatment-emergent adverse events (incidence ≥10%; n = 1154) were headache (13.1%), nausea (11.8%), and constipation (11.1%). Similar efficacy and tolerability results were shown for patients who received up to 2 years of tapentadol ER treatment.

IMPLICATIONS

Pain relief and improvements in quality of life achieved during the preceding studies were maintained throughout this extension study, during which tapentadol ER was well tolerated for the long-term treatment of chronic osteoarthritis or low back pain over up to 2 years of treatment. (ClinicalTrials.gov identifier: NCT00487435.).

A randomized, double-blind, placebo-controlled tolerability study of intramuscular aripiprazole in acutely agitated patients with Alzheimer's, vascular, or mixed dementia

OBJECTIVES

To evaluate the tolerability of intramuscular (IM) aripiprazole in patients with agitation associated with dementia.

DESIGN

A 24-hour, double-blind, placebo-controlled, randomized study.

SETTING

Sixteen healthcare facilities in the United States.

PARTICIPANTS

A total of 129 patients with acute agitation associated with Alzheimer's, vascular or mixed dementia in healthcare facilities.

INTERVENTION

Patients were randomized to IM aripiprazole (5 mg, 10 mg, or 15 mg) or IM placebo administered in divided doses 2 hours apart.

MEASUREMENTS

Safety assessments included adverse event (AE) reporting, vital signs, and electrocardiograms. Preliminary efficacy analyses used the Positive and Negative Syndrome Scale-Excited Component (PEC) scores and Agitation-Calmness Evaluation Scale (ACES).

RESULTS

There was greater incidence of AEs with IM aripiprazole (50% to 60%) than IM placebo (32.0%), but over 90% were mild or moderate in severity. The incidence of oversedation was low. PEC scores showed greater improvements in agitation with IM aripiprazole 10 mg and 15 mg compared with IM placebo.

CONCLUSION

A total of 10 mg or 15 mg of IM aripiprazole administered in divided doses was safe and well tolerated for treatment of agitation associated with Alzheimer's, vascular, or mixed dementia in long-term care. Preliminary analysis showed greater efficacy compared with IM placebo.

Aberrant melanoblast migration associated with trisomy 18 mosaicism

A patient is reported with mental retardation, facial and body asymmetry, and hyperpigmented areas limited to the right side of the body. Cytogenetic studies revealed trisomy 18 in 50% of peripheral blood lymphocytes; fibroblast cultures from the hyperpigmented area showed pure trisomy 18, while the karyotype on the unaffected side was normal. This could be an example of the 'lines of Blaschko', considered to be a form of 'human mosaicism', in which an abnormality occurred in melanocytes migrating from the neural crest. Non-disjunction of one chromosome 18 appears to be associated with the mutational event that caused abnormal migration of melanoblasts.

Comparison of olanzapine and risperidone in the treatment of psychosis and associated behavioral disturbances in patients with dementia

OBJECTIVE

The authors compared efficacy of olanzapine versus placebo and risperidone as measured by the Neuropsychiatric Inventory and Clinical Global Impression-Severity of Psychosis scale in patients with dementia-related psychosis.

METHODS

Patients with moderate-to-severe psychotic symptoms associated with dementia were recruited from outpatient or residential settings and randomly assigned to 10-week, double-blind, flexible-dose treatment with olanzapine (N=204; 2.5 mg-10 mg/day; mean: 5.2 mg/day), risperidone (N=196; 0.5 mg-2 mg/day; mean: 1.0 mg/day) or placebo (N=94).

RESULTS

Most measures of neuropsychiatric functioning improved in all treatment groups, including the placebo group, and no significant treatment differences occurred. Overall discontinuation was lowest in the placebo group, and the olanzapine group had a significantly higher incidence of discontinuation due to adverse events (16.2%) relative to placebo (3.2%) and risperidone (8.7%) groups. Treatment-emergent extrapyramidal symptoms were more numerous for risperidone- than placebo- or olanzapine-treated patients. Abnormally high prolactin levels occurred in 78.0% of risperidone patients, compared with 16.7% for olanzapine and 5.0% for placebo. The incidence of weight gain greater than 7% from baseline was higher in the olanzapine group relative to risperidone, but neither active-treatment group showed a statistical difference from placebo (1.1%). No other statistically significant and clinically relevant differences were seen for any other vital sign, electrocardiographic measure, or laboratory hematology and chemistry, including glucose, except for cholesterol, which decreased from baseline to endpoint in both active-treatment groups.

CONCLUSIONS

Patients' neuropsychiatric functioning improved with olanzapine, risperidone, and placebo treatment. There was a substantial response in the placebo group, and no significant differences emerged among treatments.

32P-post-labeling detection of DNA adducts in mononuclear cells of workers occupationally exposed to styrene

32P-Post-labeling was used to analyze for the presence of DNA adducts in 47 workers exposed to styrene in a boat manufacturing facility. Individual airborne exposures measured several times over the course of 1 year ranged from 1 to 235 mg/m3 with a mean value of 65.6 mg/m3. Two adducts were detected in the DNA of mononuclear cells of these workers. The following levels of adducts were detected: adduct 1, range 0.6-102 x 10(-8) (mean 15.8 x 10(-8); adduct 2, range 0.1-70.9 x 10(-8) (mean 14.2 x 10(-8). Significant linear relationships were found between styrene exposure and both DNA adducts (adduct 2, r = 0.330, P = 0.012; adduct 1, r = 0.244, P = 0.049). Co-chromatography experiments identified DNA adduct 1 in the exposed samples as N2-(2-hydroxy-1-phenylethyl)-2'-deoxyguanosine-3',5'-bisphosphate. DNA adduct 2 remains unidentified. No significant linear relationships were observed between the level of DNA adducts and sister chromatid exchanges, possibly because of the poor precision of the 32P-post-labeling assay (the estimated coefficients of variation for adducts 1 and 2 were 2.54 and 1.96, respectively). These results demonstrate that occupational exposure to styrene results in the formation of DNA adducts in human mononuclear cells.

Chronic therapeutic anticoagulation is associated with decreased thrombotic complications in SARS-CoV-2 infection

BACKGROUND

Thrombotic disease complicates severe SARS-CoV-2 infection and is associated with increased morbidity and mortality. Various anticoagulation strategies have been evaluated in hospitalized patients to prevent complications. The impact of chronic anticoagulation before SARS-CoV-2 infection on the risk for subsequent thrombosis has not been systematically studied.

METHODS

This was a retrospective single-center study. All patients with positive SARS-CoV-2 PCR testing from March 13, 2020, through May 6, 2020, at the University of Rochester Medical Center were identified. We included all patients receiving therapeutic anticoagulation for at least 1 month before COVID diagnosis. We documented the rate of thrombotic complications, type of anticoagulation, bleeding complications, and mortality.

RESULTS

A total of 107 SARS-CoV2-infected patients were chronically anticoagulated before SARS-CoV-2 testing with a median age of 78. Of those, 42 required hospital admission, with 17 requiring intensive care. No patients, inpatient or outpatient, were diagnosed with a new symptomatic thrombotic complication. Three patients had minor bleeding in the hospital. Thirteen (12%) patients died (69% male).

CONCLUSION

Our uncontrolled findings suggest that chronic anticoagulation at the time of infection may protect against thrombotic complications and decrease disease severity.

Untargeted adductomics of Cys34 modifications to human serum albumin in newborn dried blood spots

Metabolism of chemicals from the diet, exposures to xenobiotics, the microbiome, and lifestyle factors (e.g., smoking, alcohol intake) produce electrophiles that react with nucleophilic sites in circulating proteins, notably Cys34 of human serum albumin (HSA). To discover potential risk factors resulting from in utero exposures, we are investigating HSA-Cys34 adducts in archived newborn dried blood spots (DBS) that reflect systemic exposures during the last month of gestation. The workflow includes extraction of proteins from DBS, measurement of hemoglobin (Hb) to normalize for blood volume, addition of methanol to enrich HSA by precipitation of Hb and other interfering proteins, digestion with trypsin, and detection of HSA-Cys34 adducts via nanoflow liquid chromatography-high-resolution mass spectrometry. As proof-of-principle, we applied the method to 49 archived DBS collected from newborns whose mothers either actively smoked during pregnancy or were nonsmokers. Twenty-six HSA-Cys34 adducts were detected, including Cys34 oxidation products, mixed disulfides with low molecular weight thiols (e.g., cysteine, homocysteine, glutathione, cysteinylglycine), and other modifications. Data were normalized with a novel method ("scone") to remove unwanted technical variation arising from HSA digestion, blood volume, DBS age, mass spectrometry analysis, and batch effects. Using an ensemble of linear and nonlinear models, the Cys34 adduct of cyanide was found to consistently discriminate between newborns of smoking and nonsmoking mothers with a mean fold change (smoking/nonsmoking) of 1.31. These results indicate that DBS adductomics is suitable for investigating in utero exposures to reactive chemicals and metabolites that may influence disease risks later in life.

Alterations in leukocyte telomere length in workers occupationally exposed to benzene

Exposure to benzene, a known leukemogen and probable lymphomagen, has been demonstrated to result in oxidative stress, which has previously been associated with altered telomere length (TL). TL specifically has been associated with several health outcomes in epidemiologic studies, including cancer risk, and has been demonstrated to be altered following exposure to a variety of chemical agents. To evaluate the association between benzene exposure and TL, we measured TL by monochrome multiplex quantitative PCR in 43 workers exposed to high levels of benzene and 43 age and sex-matched unexposed workers in Shanghai, China. Benzene exposure levels were monitored using organic vapor passive dosimetry badges before phlebotomy. The median benzene exposure level in exposed workers was 31 ppm. The mean TL in controls, workers exposed to levels of benzene below the median (≤31 ppm), and above the median (>31 ppm) was 1.26 ± 0.17, 1.25 ± 0.16, and 1.37 ± 0.23, respectively. Mean TL was significantly elevated in workers exposed to >31 ppm of benzene compared with controls (P = 0.03). Our findings provide evidence that high levels of occupational benzene exposure are associated with TL. Environ.

Exposure assessment of monoterpenes and styrene: a comparison of air sampling and biomonitoring

BACKGROUND

Within- and between-worker variance components have seldom been reported for both environmental and biological data collected from the same persons.

AIMS

To estimate these variance components and their ratio for air contaminants and urinary metabolites in two different work environments and to predict the attenuation of exposure-response relationships based on these measures.

METHODS

Parallel measurements of air and urine were performed among workers exposed to monoterpenes in sawmills (urinary metabolite: verbenol) and styrene in reinforced plastics factories (urinary metabolite: mandelic acid).

RESULTS

Among the sawmill workers, variance components of the air and urinary verbenol results were similar; for the reinforced plastics workers the estimated between-worker variance component was greater for styrene in air than mandelic acid in urine. This suggests that attenuation bias would be about equal if air or biological monitoring were employed for monoterpene exposures, but would be greater if urinary mandelic acid were used instead of airborne styrene in an investigation of styrene exposure.

CONCLUSIONS

Personal air samplers provide data with similar or superior quality to urinary metabolites as measures of exposure to these monoterpenes in sawmills and styrene in reinforced plastics factories.

Physiologically-based pharmacokinetic modeling of benzene in humans: a Bayesian approach

Benzene is myelotoxic and leukemogenic in humans exposed at high doses (>1 ppm, more definitely above 10 ppm) for extended periods. However, leukemia risks at lower exposures are uncertain. Benzene occurs widely in the work environment and also indoor air, but mostly below 1 ppm, so assessing the leukemia risks at these low concentrations is important. Here, we describe a human physiologically-based pharmacokinetic (PBPK) model that quantifies tissue doses of benzene and its key metabolites, benzene oxide, phenol, and hydroquinone after inhalation and oral exposures. The model was integrated into a statistical framework that acknowledges sources of variation due to inherent intra- and interindividual variation, measurement error, and other data collection issues. A primary contribution of this work is the estimation of population distributions of key PBPK model parameters. We hypothesized that observed interindividual variability in the dosimetry of benzene and its metabolites resulted primarily from known or estimated variability in key metabolic parameters and that a statistical PBPK model that explicitly included variability in only those metabolic parameters would sufficiently describe the observed variability. We then identified parameter distributions for the PBPK model to characterize observed variability through the use of Markov chain Monte Carlo analysis applied to two data sets. The identified parameter distributions described most of the observed variability, but variability in physiological parameters such as organ weights may also be helpful to faithfully predict the observed human-population variability in benzene dosimetry.

The incidence of attempted CPR in nursing homes

We studied the frequency with which cardiopulmonary resuscitation (CPR) is attempted on residents of American nursing homes. Each author (all members of the Clinical Practice Committee of the American Geriatrics Society) completed a questionnaire in 1989 about policy and practice regarding CPR during 1988 in each of three to seven nursing homes, by questioning the medical or nursing director or the administrator. Because of the vagaries of nursing home record-keeping, data from some homes were allowed when they were "accurate to within 10%." Data from 58 nursing homes, totalling 10,836 bed-years were available. In 33 of these homes, accounting for 5,425 bed-years, CPR was never attempted. CPR was more likely to be foregone in nursing homes with religious affiliation than in nursing homes without (13 of 17 vs 18 of 38; chi 2 = 4.0; P less than 0.05). Religious affiliation was unknown for three nursing homes. Academic affiliation (10 of 16 vs 20 of 37 in non-affiliated nursing homes) and non-profit status (14 of 19 vs 16 of 23 in for-profit nursing homes) did not significantly affect the likelihood that CPR would never be used. In 31 of 54 nursing homes with explicit do not resuscitate (DNR) policies, CPR was never performed, compared to 2 of 4 homes without such policies. For nursing homes with complete data, there were 1,196 deaths in 32 facilities where CPR was never attempted compared to 1,294 deaths for 24 nursing homes with CPR. For 22 nursing homes without CPR, there were 2,172 emergency room transfers compared to 1,363 emergency room transfers in 18 nursing homes where CPR was attempted.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of autocorrelation on the estimation of workers' daily exposures

Daily 8-hr time-weighted average (TWA) measurements may not be independent since production rates, maintenance schedules, work practices, and ventilation can result in trends where consecutive values are correlated (autocorrelation). A sampling program which involves collection of measurements on consecutive days, therefore, can result in biased estimates of the mean and variance of the exposure distribution if a high degree of autocorrelation exists. Three simulated data sets were examined to assess the effects of autocorrelation on the estimation of exposure distributions. Results indicated that about 30% of estimated mean values from a highly-autocorrelated series were outside the 95% confidence interval observed for an uncorrelated series. Three data sets obtained from actual workplaces were found to have relatively little autocorrelation. This suggests that for workplaces such as those analyzed here, a random sampling program may not be necessary, and sequential sampling may produce accurate estimates of the parameters of the exposure distribution.

The value of age and severity as predictors of costs in geriatric head trauma patients

The costs of inpatient hospital care for treating head trauma were examined in 125 patients over the age of 50. Regression analysis indicated that injury severity, as measured by the admitting Glasgow Coma Scale, was a good predictor of hospital cost, while patient age was unrelated to cost. The regression relationship, however, was quadratic (not linear), indicating that least injured and severely injured patients cost less than moderately injured patients. These findings are in direct contrast with the commonly held belief that the elderly consume more hospital resources than younger patients. They suggest the need for a reexamination of the use of age in setting prospective reimbursement amounts in certain diagnoses, and in making resource allocation decisions relative to geriatric programming at the hospital level. Head trauma patients are costly because they are sick, not because they are old.

Effect of a urinary control insert on quality of life in incontinent women

The aim of the study was to evaluate the efficacy, safety and effect on quality of life of the Reliance urinary control insert (Uromed Corp., Needham, MA) in women with genuine stress incontinence. Efficacy was evaluated at baseline and at the end of the 12-month study period by standardized pad-weight studies and by rating scales measuring acceptability, incontinence symptom improvement, ease of learning, comfort and time to habituation, recorded in diaries at monthly intervals in 63 women. The SF-36 Health Survey questionnaire was used to assess quality of life status at baseline without the device and after 12 months of device use. A significant decrease in urine loss at 12 months compared with baseline was shown by standardized pad-weight studies, with and without the device in situ. Urine loss was reduced by more than 80% in 91% of the 63 patients, and 79% were completely dry. Patient diaries showed significant improvement in control of leakage, comfort, and ease of device use during the study period. Short-term-36 Health Status data also indicated significant improvement in the physical functioning score at 12 months. Urinary tract infection and hematuria were the most common adverse effects. The Reliance urinary control insert is an efficacious and safe means of controlling genuine stress incontinence in women. The device was perceived as easy to use and comfortable for these 63 women, and resulted in improved quality of life.

A note on the assessment of exposure using one-sided tolerance limits

Conceptual problems with OSHA's use of an absolute standard have led to alternative methods of assessing exposures to toxic materials in the workplace. One of these methods employs a one-sided tolerance limit. This statistical approach is explored from three points of view--identifiability, sampling strategies and statistical power. In general, assessing risk in the work environment with tolerance limits is found to give inadequate answers in several important respects.

Quantitative protein synthetic rates in various tissues of a temperate fish in vivo by the method of phenylalanine swamping

1. A single high-dose injection of 14C- (or 3H-) phenylalanine was used for measurement of protein synthetic rates in tissues of toadfish, Opsanus tau, in vivo. 2. Average rates at 20 degrees C, as per cent of tissue protein synthesized per day, were as follows: liver, 14; head kidney, 15; gill, 7.7; spleen 5.0; heart, 2.3; testis, 1.4; epaxial and pectoral muscle, 0.20-0.23. Elevated rates in muscle (0.71%/day) were found in fed fish. 3. Temperature dependency (Q10) in the 10-20 degrees C range averaged 6-7 for tissues with high rates of protein turnover, and 3-4 in heart and muscle after two-weeks acclimation.

Temporal association between serum prolactin concentration and exposure to styrene

BACKGROUND

Previous studies have suggested that occupational exposure to styrene is associated with increased serum levels of the anterior pituitary hormone prolactin (PRL).

AIMS

To test the hypotheses that: (1) the effect of styrene exposure on PRL secretion is an acute effect, not a subchronic or chronic effect; (2) blood styrene, as a measure of absorbed dose, is a stronger predictor of serum PRL level than personal breathing zone air styrene concentration.

METHODS

Subjects were recruited from 17 workplaces in the reinforced plastics industry. Personal breathing zone air styrene, whole blood styrene, and serum PRL were measured during one to three sessions, approximately one year apart. Linear multiple regression was used to model the relations between acute (air styrene or blood styrene obtained at same time as PRL), subchronic (average air or blood styrene over two or three sessions), and chronic (years of work in industry or facility times average air styrene over all sessions) indices of styrene exposure and serum PRL.

RESULTS

Acute blood styrene concentration was the strongest predictor of serum PRL concentration, with the model predicting a 2.06-fold increase in PRL (95% CI 1.11 to 3.84) for every 10-fold increase in blood styrene. Serum PRL tended to increase with increasing styrene exposure in both men and women; however, women tended to have higher PRL levels. For women, the change in blood styrene between sessions 1 and 2 was a significant predictor of the change in serum PRL between sessions.

CONCLUSIONS

Results confirm that styrene exposure enhances serum PRL concentrations and support an acute effect of styrene on PRL secretion.

Comparison of aneuploidies of chromosomes 21, X, and Y in the blood lymphocytes and sperm of workers exposed to benzene

Benzene is a primary industrial chemical and a ubiquitous environmental pollutant that causes human leukemia and maybe other malignancies. Occupational exposure to benzene has been associated with increased chromosomal aneuploidies in blood lymphocytes and, in separate studies, in sperm. However, aneuploidy detection in somatic and germ cells within the same benzene-exposed individuals has never been reported. To compare aneuploidies in blood lymphocytes and sperm within the same individuals exposed to benzene, a cross-sectional study was conducted in 33 benzene-exposed male workers and 33 unexposed workers from Chinese factories. Air benzene concentrations in the exposed workers ranged from below the detection limit to 24 ppm (median, 2.9 ppm) and were undetectable in the unexposed subjects. Aneuploidies of chromosomes 21, X, and Y in blood lymphocytes were examined by multicolor fluorescence in situ hybridization and were compared to the previously reported aneuploidies in sperm. The results showed that benzene exposure was positively associated with the gain of chromosome 21 but not sex chromosomes in blood lymphocytes. This was in contrast to analysis of sperm, where the gain of sex chromosomes, but not chromosome 21, was significantly increased in the exposed workers. Furthermore, a significant correlation in the gain of sex chromosomes between blood lymphocytes and sperm was observed among the unexposed subjects, but not among the exposed workers. The findings suggest that benzene exposure induces aneuploidies in both blood cells and sperm within the same individuals, but selectively affects chromosome 21 in blood lymphocytes and the sex chromosomes in sperm.