[Lesser validity of urinary benzene than S-phenylmercapturic acid for measuring occupational and environmental exposure to very low concentrations of benzene]

AIM

To study the validity of urinary benzene as a biomarker of low and very low exposure to this toxicant, as compared with t,t-muconic acid (t,t-MA) and S-phenylmercapturic acid (SPMA), also taking into account the influence of cigarette smoking and co-exposure to toluene on the urinary excretion of benzene.

MATERIALS AND METHODS

The results obtained in two different studies were compared: in the first, workers occupationally exposed to low concentrations of benzene (18 fuel tanker drivers and 23 filling station attendants) were compared with 31 controls and in the second, workers exposed to very low concentrations of benzene (the same 23 filling station attendants) were compared with the 31 controls. Exposure to airborne benzene and toluene was monitored with passive personal samplers (Radiello). Then the urine collected at the end of the work shift was analyzed for t,t-MA, SPMA and urinary benzene. All participants also filled out a questionnaire about their lifestyle habits.

RESULTS

There were no differences among the three groups in terms of age and smoking habit. Occupational exposure to benzene and toluene and the urinary concentrations of t,t-MA, SPMA and urinary benzene were higher in the fuel tanker drivers than the filling station attendants and higher in the latter than in the controls. Cigarette smoking was found to be associated with urinary excretion of t,t-MA, SPMA and urinary benzene at both low and very low exposure to benzene. The biomarkers t,t-MA, SPMA and urinary benzene were almost always correlated, for both low and very low exposure to benzene. Notably, for low exposure to benzene a dependency relation was found with the levels of t,t-MA, SPMA and urinary benzene on both cigarette smoking and airborne benzene, whereas for very low exposure to benzene there was a dependency relation of SPMA on cigarette smoking and airborne benzene, of urinary benzene only on cigarette smoking and of t,t-MA on none of the variables considered.

CONCLUSIONS

For occupational exposure to low concentrations of benzene, urinary benzene and SPMA showed a comparable validity, while for exposure to very low concentrations of this toxicant the validity of SPMA was confirmed while urinary benzene was found to be less useful. Cigarette smoking was the main factor conditioning the excretion of all the biomarkers of benzene in conditions of both low and very low exposure to the toxicant, so for the analysis of occupational exposure to benzene it is best to recommend abstention from smoking at least in the hours immediately before urine collection.

Treatment efficacy of language and calculation disorders and speech apraxia: a review of the literature

The aim of the study was to evaluate the efficacy of the treatment for language and calculation disorders and for speech apraxia in vascular subjects. Only therapeutic methods that could be qualified as neuropsychological were taken into account. For language disorders, we searched the pertinent literature published from 1950 to August 31, 2007 by means of electronic data banks and we took into consideration the Cochrane review, and papers in Cicerone et al. and Cappa et al. systematic reviews. For acalculia we examined the literature from 1980 by carrying out research on electronic data banks; for speech apraxia, studies emerged from a search of PUBMED. Aphasia therapy has been clearly demonstrated efficacious in groups of subjects if sufficiently prolonged/intensive. Treatment for specific disorders (words and sentences processing, reading, writing) studied in series of single patients, though always efficacious, reaches a lower level of recommendation due to the lack of RCT. Only a few studies tackled the problem of efficacy in case of speech apraxia and calculation disorders. Results are positive but data are scanty. Efficacy of aphasia therapy seems well established in group of subjects and well-promising for speech apraxia and calculation disorders. It is suggested, however, that the term "aphasia" covers widely different impairments and that RCT are not the best instrument to evaluate efficacy; the importance of chronicity is underlined.

[The role of the occupational physician in the assessment of accident risk]

The prevention of accidents at work in Italy is a target still to be reached for the safety of workers in workplaces, despite the innovative provisions introduced by the Legislative Decree 81/08 and the decrease of the number of total and fatal accidents occurred in the period 2001-2008, as reported in the statistics of the Italian Workers' Compensation Authority (INAIL). The occupational physician performs a very important role in the accident risk assessment, based on his biomedical and ergonomic knowledge. His role is carried out during the phase of safety risk assessment, contributing to assess plants, machines, tools, personal protective equipments, to be used by the workers. His knowledge of the health status of workers, acquired by medical surveillance and aimed to prevent accidents by providing the fitness for work evaluation in relation to the presence of diabetes mellitus, musculoskeletal diseases, sleep disorders, or to the assumption of hypnotic drugs, when the employee works at height or as driver such as in the transport or construction industry, is not less important. Unfortunately, this latter role of the occupational physician is limited because the Italian Safety Legislation does not provide for the sanitary surveillance of all the workers employed in factories.

Optimized synthesis of phosphatidylserine

The synthesis of phosphatidyl serine containing saturated fatty acids was thoroughly studied and optimized in order to establish a protocol amenable to large-scale synthesis. The key step was a one-pot multicomponent reaction involving an O-benzyl phosphorodiamidite, protected serine and diacylglycerol, followed by in situ oxidation of the resulting phosphite. In order to replace expensive and poorly stable tetrazole, a screening of substitutes was carried out and imidazolium chloride was selected as the best suited one.

[A case of Kaposi's sarcoma in the rapamycin era]

We report a case of Kaposi's sarcoma in a patient who received a double kidney transplant in 2005. Immunosuppression was induced with rapamycin and antilymphocyte serum while maintenance therapy consisted of rapamycin, corticosteroids and mycophenolic acid. The patient developed delayed graft function but no rejection. In November 2006 and March 2007 two graft biopsies were taken because of a significant rise in serum creatinine; they revealed chronic allograft nephropathy and polyomavirus infection. Meanwhile a skin biopsy of the leg was performed to determine the nature of a discolored lesion. The morphohistological diagnosis was Kaposi's sarcoma. For this reason rapamycin was stopped and steroid treatment gradually reduced. Specific therapy with doxorubicin was started; radiological and endoscopic examination excluded disseminated disease while serological tests were positive for antibodies to HHV-8, a virus known to cause Kaposi's sarcoma. Unfortunately, withdrawal of antirejection therapy caused loss of the graft, so the patient had to start dialysis. In this report we stress the possible development of malignancy in transplanted patients who are given rapamycin. Rapamycin is known to be an antirejection drug and to have antineoplastic activity; the major risk of malignancy is probably related to immunosuppression rather than the type of drugs used to obtain it.

[Sleep disorders in cement workers]

Obstructive Sleep Apnea Syndrome (OSAS) and Excessive Daytime Sleepiness (EDS) are sleep disorders which can increase cardiovascular risk. An health survey was performed on the cement workers to estimate the prevalence of sleep disorders and to investigate occupational, personal and health risk factors that could influence it. A total of 761 male workers, employed at 10 different cement plants of South Italy and Sicily, were examined. All subjects gave informed consent to take part in the survey. The following questionnaires were administered: Berlin Questionnaire to estimate the high risk of OSAS, Epworth Sleepiness Scale for EDS, a questionnaire posing questions about working conditions, personal characteristic, lifestyle, past history of disease and present illness. Statistical analysis was performed with the statistical package SPSS. The prevalence of high risk of OSAS and of EDS resulted respectively in 24.2% and 3.4% of workers. Sleep disorders detected with the two questionnaires were significantly associated. A positive and significant association between OSAS and respectively age, time of employment, BMI, ex-smoker status, neck, waist or hip circumferences, chronic fatigue and arterial hypertension was observed. Subjective variables regarding working conditions (job interest, evaluation oforganization of work and job satisfaction) and alcohol consumption were not associated with the high risk of OSAS. Shift work (2 and 3 shifts) was not associated with the high risk of OSAS. An healthy worker effect was observed for workers who changed from shift work (2 or 3 shifts) to fixed daytime work. For them, this change to fixed daytime work was conditioned by chronic disease like hypertension and obesity. EDS was not dependent, associated or correlated with any of the occupational, personal or pathologic variables investigated in the study. In conclusion the research showed no relationship between working conditions, particularly shift work, and the high risk of OSAS, and the influence of obesity in determining the high risk of OSAS, itself a potential cardiovascular risk factor. The interest of occupational physician has been focused on introducing in health surveillance also measures of health promotion regarding sleep disorders with the aim of preserving health condition in workers.

[Validity of urinary 2-thiothiazolidine-4-carboxylic acid (TTCA) as biomarker of exposure to very low concentrations of carbon disulphide: preliminary results]

The possibility to use urinary 2-thiothiazolidine-4-carboxylic acid (TTCA) as biomarker of occupational exposure to very low doses of carbon disulphide (CS2) was evaluated preliminarily in 10 workers employed in a chemical plant where rubber vulcanization accelerators are produced, and in 10 workers, residents in the same geographical area and not occupationally exposed to CS2 and dithiocarbamates (DTC). Exposure to airborne CS2 was assessed, only for exposed workers, by both personal and area samplers. For the determination of TTCA, a spot urine sample was collected for each worker, exposed and non exposed, at the end of work-shift. A questionnaire probing lifestyle and dietary habits and non occupational exposure to CS2 and DTC was administered to all workers involved in the study. Environmental exposure to CS2 in 2007 ranged between 0.21 mg/m3 and 0.73 mg/m3 for personal sampling, and between 0.23 mg/m3 and 0.41 mg/m3 for area sampling. Urinary TTCA levels resulted very low and did not show any significant difference between exposed (Median: 10.8 microg/g creat; Range: 6.1-26.4 microg/g creat) and non exposed workers (Median: 9.3 microg/g creat; Range: 3.0-33.0 microg/g creat), while higher, but not significant concentrations of TTCA were observed in smokers than in non smokers (p = 0.09). No correlation was found between urinary TTCA levels and environmental exposure to CS2, age, body mass index, smoking and dietary habits. In conclusion, the low sensibility and specificity in the assessment of occupational exposure to low doses of CS2 in workers compared to general population subjects, makes urinary TTCA a biomarker with a low usefulness in biological monitoring. ACGIH, besides, should also introduce "B" (background) notation, at present not considered for the BEI indicated for urinary TTCA.

[Influence of cigarette smoking on the excretion of urinary benzene in filling-station attendants]

The influence of cigarette smoking on concentrations of urinary benzene, a sensitive and specific biomarker proposed for biological monitoring of exposure to very low doses of benzene, was investigated in 24 filling-station attendants and 31 workers non occupationally exposed to benzene. Environmental monitoring was performed by personal passive samplers "Radiello", and a spot urine sample was collected at the end of the work shift, from all subjects, for the determination of urinary benzene. Exposure to benzene resulted significantly higher in filling-station attendants (mean 23.3 +/- 17.0 microg/m3; range 4.5-66.3 microg/m3) than in controls (mean 4.6 +/- 2.6 microg/m3; range < 3-11.5 microg/m3), while concentrations of urinary benzene did not show any significant difference between the two groups. Considering all subjects as a single group, it was observed that urinary benzene concentrations were positively correlated with the number of cigarettes smoked during the sampling time (rho = 0.38; p = 0.047) and with airborne benzene levels (rho = 0.32; p = 0.019), and negatively correlated with the time elapsed between the last smoked cigarette and urine collecting (rho = -0.40; p = 0.045). Multiple regression analysis confirmed the influence of cigarette smoking on urinary benzene concentrations. In conclusion, our study showed the validity of urinary benzene as a biomarker for biological monitoring of exposure to very low doses of benzene, although cigarette smoking determined a prevalent etiological role at the low environmental benzene concentrations observed.

[Significance and limitation of creatinine adjustment for urinary chromium and arsenic in biological monitoring of occupational exposure to these metallic elements]

Creatinine adjustment has been used to remove the influence of the effect of urine dilution on exposure biomarkers measured in spot samples. This research aimed to determine the reliability of creatinine adjustment for urinary chromium and arsenic in subjects from general population considering interferences able to influence creatinine excretion. 444 male subjects were examined and each participant was administered an anamnestic questionnaire. Chromium and arsenic were determined on second morning void urine samples by atomic absorption spectrophotometry and creatinine by Jaffè method. Urinary creatinine showed a significant negative decrease with age increasing (p < 0.001). Chromium concentrations resulted higher in subjects with renal disease, particularly after creatinine adjustment (p = 0.014). Age was negatively correlated with urinary creatinine (rho = -0.23; p < 0.001), and positively with chromium (rho = 0.13; p = 0.007) and arsenic (rho = 0.17; p = 0.004), only after creatinine adjustment. A positive correlation was also found between unadjusted chromium and arsenic (rho = 0.10; p = 0.039) and between urinary creatinine and both unadjusted chromium (rho = 0.32; p < 0.001) and arsenic (rho = 0.18; p < 0.001). An high coefficient of correlation was observed between unadjusted chromium (rho = 0.88; p < 0.001) and arsenic (rho = 0.90; p < 0.001) and the respective adjusted values. Multiple regression showed a dependence of urinary creatinine and adjusted chromium and arsenic concentrations on age. In conclusion, although chromium and arsenic seem to have a renal kinetics of excretion comparable to the creatinine one, the influence of age on creatinine elimination suggests that the expression of urinary values of these metallic elements as microg/L is more reliable.

The anti-schistosomal drug praziquantel is an adenosine antagonist

The mechanism of action of praziquantel (PZQ), the drug of choice against schistosomiasis, is still unclear. Since exposure of schistosomes to the drug is associated with calcium influx and muscular contraction, calcium channels have been suggested as the target, although direct combination of PZQ with their subunits was never demonstrated. We report a hitherto unknown effect of PZQ, namely the inhibition of nucleoside uptake, as observed in living worms using radio-isotope labelled adenosine and uridine. This effect is clearly seen in schistosomes but is absent in mammalian cells in culture. Moreover it is a specific pharmacological effect seen exclusively with the active levo-R(-)stereo isomer of the drug, and is shared by at least one benzodiazepine having antischistosomal activity. This novel effect acquires significance given that schistosomes cannot synthesize purine nucleosides de novo. A possible relationship between this novel effect and the known action of PZQ on calcium channels is discussed, since adenosine is known to bind to specific receptors and to behave as an indirect antagonist of calcium release in mammalian cells. If calcium channels were correlated with adenosine receptors also in schistosomes, as they are in mammals, this would support the hypothesis that PZQ-induced calcium influx may be correlated to adenosine receptor blockade.

Fractal characterisation of boundary irregularity in skin pigmented lesions

A growing literature shows researcher's interest in fractal analysis, arising from its ability to describe and characterise quantitatively the complexity of several tumour profiles. The aim of the work was to investigate the fractal properties of skin pigmented lesion boundaries. Although melanoma is one of the most aggressive tumours, early detection and a high rate of diagnostic accuracy, followed by timely excision, can allow complete recovery in melanoma patients. A modified approach to fractal dimension estimation was performed that was able to consider, in a data fit procedure, the range in which lesions show fractal properties. Identification of this zone is the most important step towards a correct fractal analysis procedure. The method was checked against a known fractal dimension object (Koch's curve) with an error of 0.007. The fractal dimension was estimated in 110 skin pigmented lesions and showed a significantly increasing linear regression (p < 0.05), from common naevi to naevi with dysplasia to melanomas. This result is important for screening, as it can inform the decision to excise precociously malignant lesions or to avoid unnecessary removal of benign ones. The limitations of the method are discussed.

[Evaluation of myopia in a group of people working with video terminals: first results]

Since the 70's the occupational use of electronic systems equipped with visual display terminals (VDTs) became wide-spread also in Italy. Some longitudinal studies on large samples of VDT workers found no significant changes of myopia (M) with regard to years and daily hours spent working at a VDT.

OBJECTIVE

To evaluate the prevalence and the time course of M in 209 VDT workers employed in the service sector.

MATERIALS AND METHODS

After obtaining workers' informed consent their work, social, family and personal medical histories were collected. Myopia was defined as need of >0.25 D negative spherical correction. Average daily hours duringfollow-up and overall years spent working at a VDT were calculated as exposure indexes.

RESULTS

The mean baseline age was 39.2 years (SD: 8.7, min-max: 22-62) and the mean education was 14 years (SD: 2.2). The mean follow-up period was 5.5 (3-9) years. The prevalence of M was 45.5% at the start and 49.8% at the end of the study. It was higher in workers with >13 years of education and in those < 40 year-old. A slight but significant increase of the degree of M (dioptres) occurred during the follow-up. The change in the degree of M was not different between the classes of VDT exposure (< or = 4 and >4 daily hours; < or =15 and >15 years spent), of education and of age at the end of follow-up.

DISCUSSION

The high mean educational level can partly explain the higher prevalence of M detected in the workers on study with respect to the one described elsewhere on VDT workers and general population. The progression of the M seems not to be related to the professional and personal variables analyzed, but to depend on the natural evolution of M. Further studies are needed to confirm these preliminary data in larger groups of VDT workers.

[Could VDT use induce thoracic hyperkyphosis? Preliminary data]

The association between sitting posture and degenerative alterations of intervertebral disks has been widely studied, while the possible relationship between sitting posture and thoracic hyperkyphosis has not been investigated sufficiently. The objective of this study, therefore, is to verify the possible association between video display terminal (VDT) use, which needs a sitting prolonged posture, and thoracic hyperkyphosis. 63 VDT workers and 71 telephone line maintenance workers (control group) have been examined. The two groups were different for the postural load required by the two jobs. A questionnaire about job and clinical history has been administered to workers included in the study. A complete orthopedical examination has been performed for all workers, while radiographic exams have been performed only in the cases requiring of further diagnostic investigations. The two groups have resulted homogenous for age, while were different for working age and body mass index (BMI). The frequency of subjects with rachialgia has resulted higher in VDT users than in maintenance workers. The prevalence of thoracic hyperkyphosis observed in VDT users has been higher than in maintenance workers, with a difference near to be statistically significant, and significantly associated with age in VDT users. The hyperkyphosis of the dorsolumbar tract have resulted significantly more frequent in VDT users than in maintenance workers (p<0.05). Preliminary results of this study suggest that fixed and prolonged sitting working posture would be able to determine thoracic hyperkyphosis, although constitutional factors and age could have a role in its determination. Preventive measures should be proposed for an adequate ergonomic training of VDT users.

[Oxidative stress in station service workers]

INTRODUCTION

The aim of this study is to identify an oxidative stress in service station workers. Previous studies verified an increased incidence of leukemia and myeloma, however other authors haven't verified it. There are reports of nasal, pharyngeal, laryngeal, and lung cancer in service station workers. Our study wants to evaluate the oxidative balance in the fuel workers.

MATERIAL AND METHODS

We studied 44 subjects with gasoline exposure and 29 control subjects. We determined the blood concentrations of Glutathione reduced and oxidized, Protein sulfhydrylic (PSH) Vitamine E, Vitamine C, Malondialdehyde, Protein oxidized (OX-PROT) and beta carotene. The t test was performed to analyze the differences between the means, the Chi square was used to evaluate the statistical significance of associations between variable categorical (redox index). The Anova test excluded the confusing effect of age, smoke and alcohol habit.

RESULTS

The mean age of the workers was 36.6 years, instead the control group was 38. In the workers Glutathione reduced, Vit. E and Beta carotene were lower than in the control subjects, this difference was statistically significant (p < 0.01). The Malondialdehyde concentration was higher in the workers higher than in the control group, but this difference wasn't statistically significant.

DISCUSSION AND CONCLUSIONS

Our data demonstrated Glutathione, Vit. E, and Beta carotene are useful to verify a reduction of the antioxidant activity. The only marker of the presence of oxidative injury that correlated to work exposure was the malondialdehyde. The redox index was surest marker. The limit of our study is the number of control group, it was little and lower than workers. Conclusively we believe it's useful to continue our studies and, if our results are going to be confirmed, we retain that stress oxidative determination would be verified in occupational medicine using these markers, especially to study exposure of the fuel workers who were investigated less and, in our opinion, would receive more attention.

Analytical control of photocatalytic treatments: degradation of a sulfonated azo dye

The degradation of Methyl Orange (C(14)H(14)N(3)SO(3)Na), chosen as a model sulfonated azo dye, was investigated in aqueous solutions containing suspended polycrystalline TiO(2) particles under irradiation with simulated sunlight. The dye disappearance and the formation of the mineralization end products were monitored; the formation of the main transient intermediates was also examined in detail. Particular attention was devoted to the identification and to the evolution of fragments retaining the chromophoric group. The comparison of data coming from various analytical techniques led to a possible reaction mechanism for the degradation process, giving insight into an aspect of the treatment which has not been considered in previous studies.

Effect of shift work on body mass index: results of a study performed in 319 glucose-tolerant men working in a Southern Italian industry

OBJECTIVE

To examine the influence of shift work on metabolic and cardiovascular risk factors in subjects working in an industry sited in Apulia, Southern Italy.

DESIGN

Cross-sectional study of metabolic effects of shift work in glucose tolerant workers in a chemical industry in southern Italy.

SUBJECTS

The subjects included 319 glucose tolerant male individuals, aged 35-60 y.

MEASUREMENTS

Anthropometric parameters (body mass index (BMI) and waist-to-hip ratio (WHR)), fasting concentrations of glucose, insulin, and lipids (total cholesterol, HDL-cholesterol, triglycerides), the sum of glucose levels during 75 g-oral glucose tolerance test (Sigma-OGTT), and systolic and diastolic blood pressure (SBP and DBP, respectively).

RESULTS

The prevalence of obesity was higher among shift workers compared to day workers, whereas body fat distribution was not different between the two groups. Shift workers had higher BMI than day workers, and shift working was associated with BMI, independently of age and work duration. Shift workers had significantly higher SBP levels, which were independently influenced by BMI, but not by shift work, thus suggesting that the difference in SBP may well be mediated by the increased body fatness.

CONCLUSION

In workers of an industry sited in Southern Italy, shift work may be directly responsible for increased body fatness and is indirectly associated with higher blood pressure levels and some features of metabolic syndrome.

[Occupational exposure to inhalation anesthetics: 10 years of measurements at hospitals in Puglia]

The Authors provide the data gathered from measurements of nitrous oxide in the operating room of Puglia during the period between 1993 and 2003. They prove significant reductions of pollution according with time and they verify lower pollution levels in the operating rooms of private hospitals with respect to public facilities. The importance of the maintenance of gas distribution and evacuation systems is shown and a method of environmental and biological monitoring is provided. Finally, the Authors prove the utility of the graphic representation of the measurements, conduced utilising dedicated instrumentation.