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Biomedical subjects

A Cavalleri

Publications and source records attributed to A Cavalleri.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

Reliability of urinary 6-sulfatoxymelatonin as a biomarker in breast cancer.

The objective of this study is to evaluate the effect of cryopreservation at different storage temperatures on urinary 6-sulfatoxymelatonin (aMT6s) concentration. Overnight urine from 28 postmenopausal women participating in the ORDET cohort study was filtered and separated into 6 mL aliquots. Urine samples were stored at -80 degrees C and at -30 degrees C for an average of 14 years. Urinary aMT6s concentration was assessed using a competitive immunoassay. Mean aMT6s values of samples stored at -30 degrees C were systematically lower than those of samples stored at -80 degrees C (10.7 ng/mL versus 15.8 ng/mL, p<0.001). Bland Altman plots showed disagreement between determinations at different storage temperatures at the highest levels of the metabolite concentration. The degree of agreement evaluated in terms of intraclass correlation coefficient was 0.68 (95% CI 0.41-0.84, p<0.0001). Pearson's correlation coefficient between aMT6s values of the two differently stored samples was 0.93 (p<0.001), while the Kendal tau coefficient for rank distribution was 0.73 (p<0.001). Our data suggest that storage temperatures might affect degradation of aMT6s during storage. However, individual characterization by melatonin levels does not seem to be affected by cryopreservation conditions.

Adult↗
PubMedDate not supplied

[Significance of urinary concentrations of S-benzyl-N-acetylcysteine (S-BMA) in subjects exposed to toluene].

Toluene is a widely diffuse solvent for oils, resins, rubber and paints, either alone or as a major component in a mixture; in the industrial environment it is currently present at concentrations of ppm. Toluene can be absorbed via the lungs or via the skin. The absorption of toluene via inhalation is related to the exposure level as well as the activities level of workers. Once absorbed into the body, toluene is metabolized in man to benzoic acid, followed by hepatic cytochrome P450 catalyzed glycine conjugation to form hippuric acid. Relatively small amounts appear in urine as o-cresol and p-cresol where they occur as glucoronide and sulfate derivate. Only a minor fraction of inhaled solvent is conjugated with glutathione with the production of S-benzyl-N-acetylcysteine (S-BMA). Several biological indicators have been proposed for evaluating toluene exposure in the workplace. These include urinary hippuric acid, toluene in blood, toluene in breath, o-cresol in urine and toluene in urine. We examined a group of 18 workers occupationally exposed to toluene, determining the concentrations of toluene in ambient air and S-BMA in urine. All urine samples were collected at the end of work shift. The renal excretion of S-BMA showed highly significant correlations with environmental data and with the other established parameters of biological monitoring of toluene. The median ambient air concentration was 15.7 ppm ranging from 2.9 to 70.3 ppm, the median concentration of S-BMA was 16.0 micrograms/g creatinine. S-BMA was detectable in urine samples of a control group of 87 subjects non occupationally exposed to toluene. Most of unexposed subjects showed S-BMA values lower than 10 micrograms/g creatinine both in smokers and in nonsmokers and no significant difference was found in samples (20) collected at three intervals during one day. Our finding further indicates that the metabolite S-BMA could be a marker of occupational toluene exposure.

Acetylcysteine↗
PubMedDate not supplied

[Measurement of N-methylformamide in occupational exposure to N,N-dimethylformamide].

N,N-dimethylformamide (DMF) is a solvent that is widely used in industry. The major occupational sources of exposure results from production of synthetic leather. The main metabolite formed in both man and animals is N-hydroxymethyl-N-methylformamide. Demethylation leads to N-methylformamide (NMF) and formamide and also to a small extent to hydroxy-methylformamide. All the metabolites are excreted in urine, as are very small amounts of the unchanged substance. N-acetyl-S-(N-methyl-carbamoyl)-cysteine can be determined in urine as a further metabolite. We conducted this biomonitoring study with the aim of evaluating the correlation between the excretion of N-methylformamide (mainly from N-hydroxymethylformamide) and levels of exposure to N,N-dimethylformamide among occupationally exposed people. The mean time-weighted average (TWA) exposure was about half (13.5 mg/m3) of the current threshold limit value, the range of the values varying from 0.4 to 75.2 mg/m3. A linear equation existed between urinary NMF concentration and DMF concentration in the environment. The findings show that the urinary NMF concentration can be used as an appropriate biological exposure index. The authors suggest for occupationally exposed subjects, a urinary NMF concentration corresponding to the time-weighted average of the threshold limit value of 39.9 mg/l (37.2 mg/g creatinine) and a 95% lower confidence limit (biological threshold) of 23.4 mg/l (22.2 mg/g creatinine).

Adult↗
PubMedDate not supplied

[Biological monitoring of occupational exposure to desflurane].

In these last years Desflurane (D) has become used, alone or in combination with nitrous oxide, in surgical procedures. Occupational exposed groups include anesthesiologists, other physicians, (e.g. surgeons) and operating room nurses. Desflurane is a halogenated methylethylether which is administered by inhalation. Desflurane is halogenated exclusively with fluorine. The blood/gas partition coefficient of Desflurane is 0.42. Changes in the clinical effects of Desflurane rapidly follow changes in the inspired concentration. Studies in man indicate that Desflurane washes into the body rapidly. It also washes out of the body rapidly, allowing flexibility in adjustment of the depth of anaesthesia. Desflurane is eliminated via the lungs, undergoing only minimal metabolism (0.02%). In order to investigate the role of urinary D as an indicator of occupational exposure to Desflurane (CI, ppm), CI was measured in 21 members of operating room staffs. For the measurement of environmental concentration of Desflurane (CI), the ambient air was sampled using personal passive dosimeters. The analyte was desorbed by a water-methanol mixture and was analysed by means a gas chromatograph--mass spectrometer (GC-MSD) and headspace technique. The biological monitoring of exposed workers was conducted by determining the concentration of Desflurane in urine (Cu, microgram/L). Urine concentrations of Desflurane were determined by headspace analysis using GC-MSD. Significant correlations were found between the environmental Desflurane concentration and the urinary concentrations. The correlation between CI (ppm) and Cu (microgram/L) was: Log D (Cu, microgram/L) = .191 + .922 * LogCI; r = .916 On the basis of the equation it was possible to establish tentatively the biological limit values corresponding to the respective occupational exposure limit values proposed for Desflurane.

Air Pollutants, Occupational↗
PubMedDate not supplied

[The determination of serum amino-terminal procollagen type-III propeptide (PIIINP) in occupational exposure to rock wool fiber].

Fifty-six males workers exposed to rock wool during production, and 20 referents were examined. Exposure, evaluated by personal sampling, ranged from 0.05 to 0.74 fibres/ml (median 0.15). The subjects underwent a medical examination, chest X-ray according to ILO recommendations and pulmonary function tests. In all subjects the serum levels of type III procollagen N-terminal propeptide (PIIINPs) were determined. No evidence of pulmonary fibrosis, nor work-related lung diseases were observed. PIIINPs mean values in the exposed (9.8 ng/ml; 2.8 S.D.) were slightly higher, but not significantly different when compared to referents (8.5 ng/ml; 2.5 S.D.). No significant correlation between PIIINPs and rock wool exposure (both airborne levels and exposure duration) was observed. Furthermore, peptide levels were not related to pulmonary function test results. Our results suggest that occupational exposure to rock wool fibres lower than 0.75 fibres/ml for less than 20 years does not induce definite cases of pulmonary fibrosis nor an increase of type III collagen synthesis in the lung.

Air Pollutants, Occupational↗
PubMedDate not supplied

[Identification of occupations with greater risk of accidents and micro-accidents].

Occupational accidents represent an important problem in Occupational Medicine, not fairly investigated till now; as a consequence, data on the matter are lacking. The frequency of accidents is higher in the building, metal and wood industry. As regard to mycro-accidents, information are deeply lacking, and any comparison among different occupational groups is difficult, even if for some workers the risk is high. A very important issue concerning labour injuries is at present time represented by the risk of occupational HIV infection. From this point of view, we can distinguish three groups of workers: 1) health care workers (the group at highest risk); 2) other workers at risk of direct contact with infected blood, such as low-enforcement and correctional-facility officers; 3) workers not at risk of blood contact for occupational causes. Only in the first group some cases of seroconversion (18 until 1988) have been documented. The risk of occupational infection by HIV seems currently low, but a great effort must be devoted to accidents prevention, especially in relation to the great increase of seropositivity prevalence in the population.

Accidents, Occupational↗
PubMedDate not supplied

[The McCollough effect and visual fatigue induced by the use of green phosphorus monochromatic video terminals].

We examined 101 students (40 men, 61 women) aged 16-19 years, working 1-3 hours daily with video display terminals (VDT) with luminous green characters on dark background. McCollough visual aftereffect (ME) was reported, almost occasionally, in 80.2% of the examined group. 68% of the students referred daily ME appearance. Usually the effect appeared after 1 hour or less of VDT work and might persist for 1 hour or more. ME prevalence and persistence were significantly greater in women than in men. Apparently no relations were observed between ME prevalence and VDT work hours of visual defects. ME prevalence and persistence were significantly related to VDT induced visual asthenopia symptoms, but not with ocular asthenopia. According to our results, ME appearance may represent an early index of individual susceptibility to visual asthenopia induced by green characters VDT and/or be itself a precocious visual asthenopia symptom.

Adolescent↗