Giorgio Marcuzzo

Otoneurological study in workers exposed to styrene in the fiberglass industry

Twenty workers exposed to styrene and acetone in small fiberglass factories were monitored for 8 h using passive dosimeters. Urine samples were collected at the end of the workshift and before the start of work on the next morning. The 8-h time-weighted average exposure values for styrene and acetone ranged from 14 to 416 mg/m3 and from 70 to 277 mg/m3, respectively. The sum of styrene metabolites, mandelic acid and phenylglyoxylic acid (MA + PGA), in the next-morning urine samples ranged from 81 to 943 mg/g creatinine. Different test sensitivity was identified in the otoneurological battery: it was low for audiometric tests and ABR, and relatively high for vestibular tests. The vestibular system seems partially sensitive to the toxic effects of styrene in the absence of clinical signs and symptoms. The actual exposure levels for styrene cannot be considered devoid of functional subclinical consequences.

Biological monitoring of workers exposed to styrene and acetone

SummaryTwenty-two workers exposed to styrene and acetone in two fiberglass industries were monitored on Monday and Thursday for 8 hours using passive dosimeters. Urine samples were collected at the end of the workshift and before the start of the work on the next morning (Tuesday and Friday). The charcoal disks of the passive dosimeters were analysed by gas-chromatography. Mandelic acid (MA) and phenylglyoxylic acid (PGA) were measured using a HPLC method; values were expressed in mg/g of creatinine. The 8-h TWA exposure values for styrene and acetone ranged respectively from 22 to 522 mg/m 3 and 40-1581 mg/m on Monday; 25–423 mg/m3 and 55–579 mg/m3 on Thursday. Styrene TWA exposure values significantly correlate with the sum of metabolites at the end of workday (r = 0.70 on Monday and r = 0.95 on Thursday) and also at the next morning (r = 0.86 on Tuesday and r = 0.85 on Friday). A styrene exposure level of 213 mg/m3 (ACGIH-TLV) was associated with an excretion of metabolites (MA+PGA) higher on Thursday (803 mg/g Great) than on Monday (570 mg/g creat). The same result was found on Friday (459 mg/g creat) compared with Tuesday (305 mg/g creat). Moreover our data show that the simultaneous exposure to acetone does not modify the excretion of MA. In conclusion the TLV of styrene is associated with different values of metabolites at the beginning and at the end of the work-week.

The rs2274911 polymorphism in GPRC6A gene is associated with insulin resistance in normal weight and obese subjects

Identification of the novel endocrine role of osteocalcin (OC) and its receptor GPRC6A has given rise to a new branch of research in OC/GPRC6A axis related to glucose metabolism. GPRC6A‐ and OC‐deficient mice share features of the metabolic syndrome, in addition to male infertility. Recently, the polymorphism rs2274911 in GPRC6A was shown to be associated with testicular impairment. We aimed to investigate the role of rs2274911 polymorphism in glucose and lipid metabolism in a cohort of normal weight and obese subjects

Circulating Stem Cells Associate With Adiposity and Future Metabolic Deterioration in Healthy Subjects

CONTEXT Obesity and metabolic syndrome are associated with mild leukocytosis, but whether hematopoietic stem/progenitor cells (HSPCs) play a role in metabolic deterioration is unknown. OBJECTIVE Our objective was to analyze the cross-sectional and longitudinal associations between CD34(+) HSPCs, adiposity, and metabolic syndrome features. DESIGN This is a cross-sectional study on 242 participants, 155 of whom were followed and included in a longitudinal assessment. SETTING This study took place in a tertiary referral center for metabolic diseases. PARTICIPANTS Healthy working individuals attending a cardiovascular screening program (total n = 3158) and having a baseline measure of circulating CD34(+) cells participated. MAIN OUTCOME MEASURES We collected demographic and anthropometric data, cardiovascular risk factors, and metabolic syndrome parameters. RESULTS Participants (34.7% males, mean age 45.9 ± 0.5 years) were free from diabetes and cardiovascular disease. Cross-sectionally, absolute CD34(+) cell counts were directly correlated with body mass index and waist circumference, inversely correlated with high-density lipoprotein cholesterol and the quantitative insulin sensitivity check index, and were higher in individuals with the metabolic syndrome. The hematopoietic component contributed most to the association of CD34(+) cells with adiposity. During a 6.3-year follow-up, high absolute levels of CD34(+) cells were associated with increasing waist circumference, declining quantitative insulin sensitivity check index and high-density lipoprotein cholesterol, and with incidence of metabolic syndrome. Relative CD34(+) cell counts showed weaker associations with metabolic parameters than absolute levels, but were longitudinally associated with increasing waist circumference and metabolic syndrome development. CONCLUSIONS A mild elevation of circulating CD34(+) progenitor cells, reflecting expansion of HSPCs, is associated with adiposity and future metabolic deterioration in healthy individuals.

The Importance of Sampling Time and Coexposure to Acetone in the Biological Monitoring of Styrene-Exposed Workers

Abstract Forty-four workers exposed to styrene and acetone in the fiberglass industry were monitored on Monday and Thursday for 8 hours using passive dosimeters. The charcoal discs of the passive dosimeters were analyzed by gas chromatography. The 8-hour time-weighted average (TWA) exposure values ranged from 10 to 522 and 14 to 1581 mg/m3 on Monday and from 9 to 423 and 10 to 579 on Thursday for styrene and acetone, respectively. Urine samples were collected at the end of the work shift and before the start of the work shift the next morning (Tuesday and Friday). Mandelic acid and phenylglyoxylic acid were measured in the urine using a high pressure liquid chromatography method; values were expressed in milligrams/gram creatinine. Styrene TWA exposure values significantly correlated with the sum of metabolites at the end of the workday (r = 0.60 on Monday and r = 0.77 on Thursday) and also the next morning (r = 0.87 on Tuesday and r = 0.84 on Friday). Mandelic acid was always correlated with exposure bet...

Environmental and Biological Monitoring of Styrene Exposure : Urinary Excretion of D-Glucaric Acid Compared with Exposure Indices

Environmental and Biological Monitoring of Styrene Exposure: Urinary Excretion of D‐Glucaric Acid Compared with Exposure Indices: M.L. Scapellato, et al. Istituto di Medicina del Lavoro, University degli Studi di Padova—Styrene, oxidized by liver microsomal enzymes, can determine a liver enzyme induction. Urinary excretion of D‐glucaric acid (DGA), which is believed to estimate this effect, was measured in 27 workers exposed to styrene in a fiberglass plant and in 27 control subjects in order to make a comparison with environmental and biological exposure indices. In exposed workers, airborne concentrations (8‐h TWA) of styrene varied between 9 and 415 mg/m3, with styrene metabolites [sum of mandelic acid (MA) + phenylglyoxylic acid (PGA)] ranging from 93 to 2130 mg/g Cr in endshift urine samples collected on a Thursday, and from 45 to 792 mg/g Cr in samples taken before work the following morning. The correlation coefficient (r) between 8‐h TWAs and sum of urinary metabolites MA + PGA was 0.92 (y=4.06x‐36.05; p<0.001) for Thursday endshift (ES) samples, and 0.84 (y=1.46x + 46.82; p<0.001) for Friday morning samples (beginning of shift: BS). Urinary excretion of MA correlated better with exposure than that of PGA (MA: ES r=0.91; BS r=0.86. PGA: ES r=0.80; BS r=0.76). ES and BS levels of DGA in exposed subjects (equal to 4.41 ± 1.57 and 4.01 ±1.18 mmol/mol Cr respectively) were both significantly higher than the 2.93 ± 0.88 observed in 27 control subjects (Mann‐Whitney test; p<0.001). No significant correlation was found between individual exposure to styrene evaluated by the environmental concentration or by urinary metabolites and urinary excretion of DGA. Furthermore, both ES and BS urinary DGA levels increased across three classes of styrene exposure (<100, 101‐200, and >200 mg/m3, respectively, including 10, 7 and 10 workers). The DGA difference between the most exposed and the not exposed subjects was significant (ES‐DGA: z=4.03 and p <0.05; BS‐DGA: z=3.16 and p<0.05; Kruskall‐Wallis test), but individual pairwise comparisons among all other groups were not. In spite of the above results, no significant correlation was found between individual exposure to styrene and urinary excretion of DGA, so that this biomarker cannot be used to monitor the exposure effects on an individual basis.

Development of metabolic syndrome and electrocardiographic features of left ventricular hypertrophy in middle-aged working subjects

Background and aims: Metabolic syndrome (MS) leads to excess cardiovascular disease, including heart failure. Left ventricular hypertrophy (LVH) is common in MS patients, but it is unknown whether onsets of MS and LVH coincide. Herein, we tested the association between development of MS and of electrocardiographic LVH in a cohort of middle-aged individuals. Methods: We included 303 working subjects (mean age 43.0±6.2; 41% males), follo wed-up for 4.3±0.8 yr. ATP-III MS components were determined. Electrocardiographic LVH features were assessed by Sokolow and Cornell voltage indexes and Romhilt-Estes (RE) score. Results: At baseline, Cornell index was significantly higher in subjects with (no.=55; 18.2%) than in those without MS (12.8±6.4 vs 10.9±5.4 mm; p=0.023), while Sokolow index and RE score were not different. At follow-up, individuals who developed (no.=51) compared to those who did not develop MS showed a significant increase in Cornell voltage index (1.0±0.6 vs −0.55±0.3 mm; p=0.035) and RE score (0.17±0.17 vs −0.08±0.04; p=0.028). The change in Cornell index over time was directly correlated with the change in the number of MS components (r=0.133; p=0.02) and in homeostasis model assessment of insulin resistance (r=0.117; p=0.046). The association between MS onset and the increase in Cornell index/RE score was independent from confounders. Conclusions: In a young population of working subjects, the development of MS is associated with worsening features of LVH. Early LVH electrocardiographic screening in young subjects who develop MS should be considered and performed using Cornell voltage index.

Long-term voice monitoring with smartphone applications and contact microphone

In recent years, the growing interest in the recognition of voice disorders as occupational diseases has required screening methods adaptable to the clinical requirements, capable to extend the collection of baseline data. In this framework, the use of smartphones has gained increasing interest, thanks to advancements in digital technology, which made them suitable for recording and analyzing acoustic signals. Two smartphone applications, based on the Voice Care® technology, have been developed for long-term monitoring of voice activity when combined with a cheap contact microphone embedded in a collar. The applications have been tested in laboratory and used for the monitoring of teachers at kindergarten, primary school, and university. Vocal Holter App allows the selection of short and long term monitoring mode, and three different clusters of vocal parameters related to intensity, intonation, and load, respectively. Most of the results are based on the distributions of occurrences of vocal parameters. ...