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Biomedical subjects

S Ghittori

Publications and source records attributed to S Ghittori.

At least 55 records · Page 3Linked to original sources
PubMed1987

Methemoglobin and carboxyhemoglobin levels in smokers and non smokers.

The authors examined the blood of 856 subjects (377 smokers and 479 non smokers) in order to evaluate the levels of Methemoglobin (MetHb) in relationship to tobacco smoke. The Methemoglobin, Carboxyhemoglobin, Percent Oxyhemoglobin and Total Hemoglobin were measured using an automated spectrometer (IL 282 CO - Oximeter). The authors found that the levels of MetHb in the smokers exceed that in the non smokers: in fact the level of MetHb in the smokers (% MetHb = 0.63) was significantly greater than in the non smokers (% MetHb = 0.56), unlike what was reported in literature. The levels of Carboxyhemoglobin in the blood has been shown to be a useful marker of tobacco smoke absorption: a close relationship exists between COHb and cigarette smoking.

Adolescent↗
PubMed1987

[Use of gas chromatography with flame ionization (GC-FID) in the measurement of solvents in the urine].

The urinary concentration of some solvents (acetone, cyclohexane, 1,2 dichloropropane, n-hexane, methyl ethyl ketone, perchloroethylene, styrene, toluene, 1,1,1, trichloroethane) was measured by means of a gas chromatography Hewlett-Packard 5890 supplied with a flame ionization detector (GC-FID, DANI HS 3950). The coefficient of variation of the method was lower than 5%. The sensitivity of the GC-FID was very similar to what of mass spectrometer detector (GC-MSD, HP 5970 A).

Acetone↗
PubMed1987

The urinary concentration of solvents as a biological indicator of exposure: proposal for the biological equivalent exposure limit for nine solvents.

Organic solvents are generally volatile substances that are absorbed mainly through the lungs; they are eliminated chiefly through the lungs and kidneys. In urine they are present as metabolites and, in very little part, as parent compound. The urinary concentration of solvent (Cu) can be used for the biological monitoring of exposed subjects to evaluate their exposure and correlate with the Threshold Limit Value (TLV) during the working day. The authors report some results obtained with workers occupationally exposed to solvents. The results concern the correlation between urinary concentration (Cu, micrograms/L) vs. average environmental concentration (Ci, mg/m3) measured in the breathing zone. For each solvent studied (acetone, 2-cyclohexane, 1,2-dichloropropane, n-hexane, methyl ethyl ketone, perchloroethylene, styrene, toluene, 1,1,1-trichloroethane) the authors propose a Biological Equivalent Exposure Limit (BEEL) corresponding to the environmental TLV.

Air Pollutants, Occupational↗
PubMed1986

Urinary elimination of acetone in experimental and occupational exposure.

Fifteen volunteers were exposed to an acetone vapor concentration of 964-8, 610 mumol/m3 (56-500 mg/m3) for 2-4 h in an exposure chamber. Ten subjects were at rest during the exposure, and five were exposed at alternate rest and light physical exercise. Subsequently 104 workers occupationally exposed to acetone were studied. The relative uptake averaged about 53%, and the ratio of the alveolar concentration to the environmental concentration averaged about 0.28. Both for the experimentally exposed subjects and the occupationally exposed workers the urinary acetone concentration showed a linear relationship to the corresponding environmental time-weighted average concentration. A linear equation also existed between urinary concentrations and the amounts of acetone absorbed. The findings enable a consideration of the urinary concentration of the unaltered acetone as an appropriate exposure indicator and the proposal of a "biological equivalent threshold" to be used in the field of biological monitoring.

Acetone↗
PubMed1985

Urinary elimination of styrene in experimental and occupational exposure.

Twenty human volunteers were exposed to styrene vapor at 273-1 654 mumol/m3 (28.4-172.3 mg/m3) for a period of 1 to 3 h at rest (15 cases) and during light physical exercise (5 cases). Subsequently 51 workers occupationally exposed to styrene were studied during a workweek (median value 1 138 mumol/m3, geometric standard deviation 2.23). As expected, the relative uptake averaged about 65%, and the ratio of the alveolar concentration to the time-weighted average of the environmental concentration averaged about 0.15. Both in the experimentally exposed subjects and in the occupationally exposed workers the urinary styrene concentration showed a linear relationship to the corresponding environmental time-weighted average concentration. The correlation coefficients of the regression lines ranged between 0.88 (occupationally exposed group) and more than 0.93 (experimentally exposed groups). The regression coefficients were closely linked to the amount of styrene taken up and to the exposure times. The findings show that the urinary styrene concentration can be used as an appropriate biological exposure indicator whose meaning differs from that of other suggested indices. As an example, in occupationally exposed subjects performing moderate work the urinary styrene concentration corresponding to the time-weighted average of the threshold limit value is 815 nmol/l, and the 95% lower confidence limit (biological threshold) is 740 nmol/l.

Adult↗
PubMed1985

Urine/air partition coefficients for some industrially important substances.

The urine/air and blood/urine partition coefficients (lambda) of 43 commonly employed organic solvents (Aliphatic, Cyclic, Aromatic and Halogenated Hydrocarbons, Ketones, Alcohols and Esters) are reported. The analyses were performed by the multiple equilibration method (constant pressure method) using a Hewlett-Packard 5880 gas chromatograph. The lambda values proposed can be employed in the field of biological monitoring of subjects occupationally exposed to solvents vapors.

Air Pollutants, Occupational↗
PubMed1985

Respiratory measurements of occupational exposure to industrial solvents.

The authors report the parameters which rule the absorption and elimination of polluting solvent vapours in exposed subjects (Ventilation, Pulmonary Capillary Flow, Solubility Coefficients, Environmental Concentrations, Exposure Times). These parameters are included in the equations showing the absorption and elimination indexes and lung clearances. Some methods to measure the Solubility Coefficients of inert gases in biological media and the values referring to 51 industrial solvents, commonly employed or important from the toxicological point of view, are described. Finally the Authors report some experimental results obtained in exposure chamber on volunteers, and in occupationally exposed subjects directly in workplaces. The results are discussed stressing their practical usefulness in the field of biological monitoring, industrial hygiene and in preventive medicine.

Absorption↗
PubMed1984

[Changes induced by dimethylformamide on platelet function and coagulation activity].

The effect of Dimethylformamide on platelet function and on clotting system has been studied on eight workers exposed to the product, widely used in industry as a solvent of acrylic resins. A significant reduction of the number of the platelets and a drawing out of PTT and PT has been noticed. Such informations has been explained as chronical peripheral use or as modification of phospholipid components induced by DMF instead of synthesis defect, as no significant variation of the fibrinogen and of AT III values, proteins synthetized by liver, has been observed. The platelet aggregation has pointed out, in vivo, a reduction of ADP aggregation in the exposed subjects; in vitro, increasing quantities have determined an increasing reduction of the primary ADP and adrenaline aggregation.

Adult↗
PubMed1984

[Stability of esters in the blood in vitro].

The aim of this paper was to evaluate the lambda values of this group of solvents experimentally, by means of an analytical method which has already been used for other solvents. During our experiments we found that most acetates we tested (n-butyl-acetate; sec.butyl-acetate; ter-butyl-acetate; ethyl-acetate; amyl-acetate; methyl-acetate; n-propyl-acetate) were particularly unstable and hydrolyzed rapidly in alcohol and in the corresponding acid. The "in vitro" behaviour of these substances allow to draw the following conclusions: 1) For the acetates it is not possible to measure the values since the involved substances are chemically unstable in blood. 2) As it was shown by the half-life times of the "in vitro" acetates, the alcohols and the corresponding acids, are released rapidly in blood. 3) The biological monitoring of the acetates in expired air is not very significant; perhaps it is better to measure the corresponding alcohol in expired air. 4) In some cases the TLV of the alcohols is much lower than for the corresponding acetates; this finding and the rapid biotransformation we observed make us think that the TLV's proposed for some acetates are too high.

Acetates↗
PubMed1984

[N-hexane and toluene in the urine of occupationally exposed subjects. Measurement and significance of its presence].

N-hexane and toluene in the urine of occupationally exposed subjects. Measurement and significance of their presence. The determination of n-hexane and toluene in urine was performed in 23 subjects who were occupationally exposed to n-hexane and in 8 subjects exposed to toluene, by means of the head space technique. A Hewlett-Packard 5880 A gas chromatograph supplied with Hewlett-Packard 5970 A Mass Selective Detector was employed. The Authors found significant correlations between urine concentration of the substance and environmental concentration (for n-hexane r = 0,866; for toluene r = 0,770.

Adult↗
PubMed1984

n-Hexane urine elimination and weighted exposure concentration.

The concentration of n-hexane in urine was determined in 30 subjects occupationally exposed to n-hexane (median value 59.6 mg/m3) in a shoe factory. The measurement of the substance was performed by means of a Hewlett-Packard 5880 gas chromatograph supplied with a Hewlett-Packard 5970 Mass Selective Detector. The analyses were performed by the head space method (constant volume method, after determination of the urine partition coefficient by the multiple phase equilibration method). The authors found a significant correlation between the n-hexane urine concentrations (microgram/l, Cu) and the n-hexane environmental concentrations (mg/m3, Ci) (r = 0.84; Cu = 0.0669 X Ci + 0.8396).

Adult↗
PubMed1983

[An open system for exposure to noted and controlled concentrations of aeriform substances].

The AA describe the realise of an open circuit exposure chamber: it enables to reach solvent concentration levels that are continuously monitored and kept within the limits of acceptability. The room can be employed in studies and experimental researches on the respiratory absorption levels of airborne pollutants in man. The following data are reported: on microclimatic parameters, on the monitoring of CO2 concentration in the room when someone is inside, on the solvent concentration measures in different points of the room, on the monitoring of the quickness to reach the steady-state and wash-out in the room, on the available concentration ranges.

Acetone↗
PubMed1983

[Measurement of the coefficient of solubility of airborne substances in blood. II. Solvents of wide industrial use].

A list of industrial solvents largely employed and produced in Italy (and somewhere else too) is presented. Using two methods previously described, blood/air partition coefficient of such solvents have been measured. Then a discussion is made about the possibility of their employment in the field of biological monitoring of subjects professionally exposed to solvent vapours.

Acetates↗
PubMed1983

[The measurement of the solubility coefficients of gases in the blood. III. Other solvents of toxicological importance].

Solubility coefficients of 21 organic industrial solvents of toxicological importance are presented. Using a multiple phase equilibration method, blood/air partition coefficients (lambda) of such substances have been measured. The lambda-values proposed can be employed in the field of biological monitoring of subjects professionally exposed to solvent vapours.

Environmental Exposure↗
PubMed1982

[Evaluation of a new alveolar air sampler].

A new alveolar air sampler is described and tested; it can be used in monitoring subjects exposed to gas and vapours in their working places. The tests were made under different experimental conditions, using both vapours of industrial solvents as acetone, ethanol, trichloroethylene, methyl ethyl ketone, n-hexane, ethyl acetate and respiratory gas (O2, CO2).

Acetone↗
PubMed1977

[Calibration of selective samplers for respirable dust].

The AA., after a short introduction on the concepts of respirable dust consider the double stage selective samplers in the literature. They suggest three of them, which are all characterized by different suction flows; the features of separation of the dust in the air are documented by means of calibrated mixtures of aerosol. As to the penetration ACGIH curve, satisfactory results are obtainable fro the 12 mm sampler with a 10 l/min flow and for the 25.4 mm sampler with a 70 l/min flow. The tests achieved with the Dorr-Oliver 10 mm metal sampler do not agree with the above mentioned curve for a capacity included between 0.7 and 2.5 l/min.

Air Pollution↗