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Biomedical subjects

M Imbriani

Publications and source records attributed to M Imbriani.

At least 37 records · Page 2Linked to original sources
PubMed1996

Individual profiles of dyspnoea and fatigue in chronic bronchitic patients, defined by intensity and duration of submaximal workloads performed.

The subjective perception of fatigue and dyspnoea during submaximal exercise was studied in 10 chronic bronchitic patients using Borg's CR10 scale, with the aim of developing a model for the assessment of sustainable workloads (through the definition of individual perceptual profiles). Each subject performed five trials, consisting of steptests at constant submaximal workloads. Fatigue (CRf) and dyspnoea (CRd) perceptions, heart rate (HR) and duration times were measured. Maximal duration was set at 30 min. The trial was stopped if a fatigue/dyspnoea score of 7 ("very strong") or 85% of the maximum HR was reached. The growth of fatigue and dyspnoea perceptions (R) as functions of time (S) were expressed by the formula: R = a + c (S-b)n. Parameters a, b, c and n calculated for each subject and trial were (mean and SD): a = 0.49 (0.31); b = 2 (0); c = 1.3 (0.61); and n = 0.55 (0.2) for dyspnoea; a = 0.51 (0.27); b = 2 (0); c = 1.4 (0.75); and n = 0.55 (0.2) for fatigue. Individual CR3 "iso-perception" curves (W = k t alpha) for fatigue and dyspnoea in a workload/duration reference system were computed from the experimental data obtained during the five trials. Mean values of the exponent alpha were (.0.5) +/- (-0.23) for dyspnoea, and (-0.41) +/- (-0.22) for fatigue. The CR3 "iso-perception" curves represented the subjectively acceptable level of exertion (defined for load and duration). By doubling the duration and workload, CRd score increments of 1.55 (SD 0.46) and 4.9 (SD 0.42), respectively, were computed. Subjective perceptions are correlated to the intensity and duration of submaximal workload performed, and can be used in conjunction with physiological parameters to predict acceptable workloads in chronic bronchitic patients.

Bronchitis↗
PubMed1996

A method for the assessment of fitness in aerobically taxing occupations.

A good level of physical fitness is a fundamental prerequisite of many occupations, hence the importance of valid methods of fitness assessment. A method, using submaximal treadmill exercise, was tested in a group of Urban Police Officers. Physiology variables and subjective perceptions were monitored. The trend of individual variables provided a means to define the "critical" capacity which corresponded to a mean value of 6.8 MET (a "heavy activity" according to Haskell's classification). This level is proposed as a predictor of endurance and could be used in follow-up fitness assessments.

Adult↗
PubMed1995

Evaluation of occupational exposure to benzene by urinalysis.

Urinary phenol determinations have traditionally been used to monitor high levels of occupational benzene exposure. However, urinary phenol cannot be used to monitor low-level exposures. New biological indexes for exposure to low levels of benzene are thus needed. The aim of this study was to investigate the relations between exposure to benzene (A-benzene, ppm), as measured by personal air sampling, and the excretion of benzene (U-benzene, ng/l), trans,trans-muconic acid (MA, mg/g creatinine), and S-phenylmercapturic acid (PMA, micrograms/g creatinine) in urine. The subjects of the study were 145 workers exposed to benzene in a chemical plant. The geometric mean exposure level was 0.1 ppm (geometric standard deviation = 4.16). After logarithmic transformation of the data the following linear regressions were found: log (U-benzene, ng/l) = 0.681 log (A-benzene ppm) + 4.018; log (MA, mg/g creatinine) = 0.429 log (A-benzen ppm) - 0.304; and log (PMA, micrograms/g creatinine) = 0.712 log (A-benzene ppm) + 1.664. The correlation coefficients were, respectively, 0.66, 0.58, and 0.74. On the basis of the equations it was possible to establish tentative biological limit values corresponding to the respective occupational exposure limit values. In conclusion, the concentrations of benzene, mercapturic acid, and muconic acid in urine proved to be good parameters for monitoring low benzene exposure at the workplace.

Adult↗
PubMed1995

Anesthetic in urine as biological index of exposure in operating-room personnel.

The aim of this study was to determine if a relationship existed between some inhalation anesthetics airborne exposure levels (Cl) and the concentration of anesthetics in samples of urine produced throughout the exposure time (Cu). The concentrations of nitrous oxide (N2O), halothane (fluothane), enflurane (ethrane), and isoflurane (forane) in the ambient atmosphere were determined in 190 operating theaters of 41 hospitals in Italy. Nitrous oxide, halothane, enflurane and isoflurane were detected in the urine of 1521 exposed subjects (anesthetists, surgeons, and nurses). The environmental measurements were performed using personal passive samplers, and the biological measurements were performed using the head space method. Significant correlations were found between the anesthetics concentration in urine produced during the shift collected after a 4-h exposure (Cu, microgram/L) and anesthetics environmental concentration (Cl, ppm). The results show that the urinary anesthetic concentration can be used as an appropriate biological exposure index. The biological values (urinary concentration values) proposed are the following: nitrous oxide, 25 micrograms/L, for an environmental value of 50 ppm; halothane, 97 micrograms/L, corresponding to 50 ppm of environmental exposure; 6.2 micrograms/L, corresponding to 2 ppm of environmental exposure; enflurane, 145 micrograms/L for an environmental exposure of 75 ppm and 5.6 micrograms/L for an environmental exposure of 2 ppm; isoflurane, 5.3 micrograms/L for an environmental exposure of 2 ppm. The values proposed are the respectively 95% lower confidence limit and therefore should be considered as a protection for the individual, especially if each biological value is corrected according to analytical variability of the measurements. In our opinion, the method of choice in the assessment of occupational exposure to inhalation anesthetics is the measurement of the urinary anesthetic concentration.

Adult↗
PubMed1995

Low flow anaesthesia reduces occupational exposure to inhalation anaesthetics. Environmental and biological measurements in operating room personnel.

In the present study we evaluated the occupational exposure to N2O and isoflurane during open circuit (OC) (fresh gas flow > or = minute volume) and low flow (LF) (fresh gas flow = 1.5 l/min) anaesthesia. The effects of active scavenging and of a charcoal filter positioned on the exhausting branch of the ventilator on environmental and urinary concentrations of inhalation anaesthetics were also investigated. The study was carried out in the same operating room provided with non-recirculating air changes (10 per hour). It involved anaesthetists and nurses during routine activity. N2O and isoflurane concentrations (time-weighted average) were measured after 3-hour continuous exposure: 1) in the environment at the level of the personnel's breathing zone (Ci); 2) in the environment at the ventilator zone (C); 3) in urine (Cu). During OC anaesthesia without active scavenging the breathing zone concentration of both N2O and isoflurane was very high (194.6 +/- 15.2 and 5.0 +/- 0.4 ppm, respectively). The activation of the scavenging greatly reduced the breathing zone concentration of N2O (31.6 +/- 4.1 ppm) and isoflurane (1.7 +/- 0.2 ppm). LF anaesthesia (with active scavenging) significantly reduced the environmental concentration of both anaesthetics (Ci N2O and isoflurane 22.7 +/- 1.8 and 0.6 +/- 0.04 ppm, respectively). During LF anaesthesia the breathing zone concentration of N2O remained low, even without scavenging (22.7 +/- 1.8 ppm). Similar results were obtained by measuring N2O and isoflurane concentrations at the ventilator zone and in urine.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants, Occupational↗
PubMed1994

Determination of 2,5-hexandione by high-performance liquid chromatography after derivatization with dansylhydrazine.

A sensitive method for the determination of free and total urinary 2,5-hexandione (2,5-HD) using high-performance liquid chromatography with fluorescence detection was developed. After purification of urine with a disposable C18 cartridge, 2,5-HD was derivatized with dansylhydrazine; 1,3-diacetyl benzene (1,3-DAB) was added to the samples, as internal standard, prior to extraction. The resulting fluorescent adducts were separated on a reversed-phase column with a gradient mobile phase of 25 mM phosphate buffer (pH 6.4) and acetonitrile. The retention times of the 2,5-HD and 1,3-DAB derivatives were 9.4 and 13.7 min, respectively. The derivatives were detected by a fluorescence detector (excitation 340 nm, emission 525 nm). The mean recoveries of 2,5-HD and 1,3-DAB were 92.0 and 94.0%, respectively; the detection limit of 2,5-HD (signal-to-noise ratio of 3) was 5 micrograms/l in urine without hydrolysis and ca. 12 micrograms/l in hydrolyzed samples. The method was applied to 39 urine samples from workers exposed to n-hexane; the mean values were 2.597 mg/l (S.D. = +/- 0.758) for total 2,5-HD and 0.179 mg/l (S.D. = +/- 0.086) for free 2,5-HD. Urine samples of 22 non-exposed subjects showed a mean concentration of 0.437 mg/l (S.D. = +/- 0.109) and 0.022 mg/l (S.D. = +/- 0.011) for total and free 2,5-HD, respectively.

Acetonitriles↗
PubMed1993

Carbon disulfide and the central nervous system: a 15-year neurobehavioral surveillance of an exposed population.

Carbon disulfide-induced neurobehavioral effects are well known and do not need further evidence. Carbon disulfide vasculopathy and the syndromic complex resulting in depression, loss of memory and concentration, and behavior disturbances have been widely demonstrated. Less known is the evolution of the symptomatology when the environmental conditions are consistently improved, that is, the reversibility or the progression of the dysfunctions observed. This paper reports on a neurobehavioral follow-up in a viscose rayon factory carried out, in intervals, from 1974 to 1990. Several successive improvements were implemented in the plant through the years, until finally, the most radical changes were made at the end of the Seventies and these resulted in exposure levels far below the current Threshold Limit Values. A total of 493 subjects were examined and some of them were reexamined up to six times. The last examination was completed in September, 1990. In this paper, studies by our group over the 15 years of monitoring are discussed. The results show that the general mental state, as measured by neurobehavioral methods, reflects past and current exposure. This point was explored by dividing the subjects into six groups on the basis of their length of exposure and year of examination and by comparing their performances. The results show that even exposure to levels of carbon disulfide not exceeding 8 mg/m3 may induce absentmindedness and difficulties in perceptive abilities.

Adult↗
PubMed1993

On the need of a sampling strategy in biological monitoring: the example of hexane exposure.

Ambient and biological monitoring of hexane exposure were repeatedly carried out in 14 female shoe makers. Airborne hexane (Ci-H) was measured in 4-h samples collected by a diffusive method. Urinary spot samples were collected before, during (at noon), and at the end of a work shift. 2,5-Hexanedione (2,5HD) in urine collected at noon was poorly related to morning Ci-H. End-of-shift 2,5HD were also poorly related to afternoon air samples. The correlation was still relatively low when end-of-shift 2,5HD was related to 8-h TWA Ci-H (r = 0.44; P < 0.01 on a linear scale, and r = 0.58, P < 0.01 on a log-log scale). End-of-shift 2,5HD levels estimated on the basis of pre-shift values using a mathematical model were much higher (2.3 times on average) than those experimentally measured during the study period. Owing to its relatively long half-time, 2,5HD seems to be influenced not only by current exposure, but also by hexane absorbed during the day(s) preceding sampling. The lack of a sampling strategy may account not only for inconsistencies between environmental and biological data, but also for a possible misuse of biological monitoring when utilized for risk assessment. Despite sometimes poor correlations with Ci-H, 2,5HD may still be preferred to other indicators as a marker of effective internal dose. A sampling strategy should ensure that measured values are representative of the individual risk for adverse effects.

Adult↗
PubMed1993

Urinary excretion of unmetabolized benzene as an indicator of benzene exposure.

Benzene concentrations in urine samples (Cu, ng/L) from 110 workers exposed to benzene in chemical plants and gasoline pumps were determined by injecting urine supernate into a gas chromatograph. The urine was saturated with anhydrous N2SO4 to facilitate the passage of benzene in the air over the urine. The solvent was stripped from the urine surface and concentrated on an adsorbent substrate (Carbotrap tube) by means of a suction pump (flow rate 150 ml/m). Wash-up of the head space was achieved by simultaneous intake of filtered air through charcoal. Benzene was thermically desorbed and injected in a column (thermal tube disorder, Supelco; 370 degrees C thermal flash; borosilicate capillary glass column SPB-1, 60 m length, 0.75 mm ID, 1 microns film thickness; GC Dani 8580-FID). Benzene concentrations in the urine from 40 non-exposed subjects (20 smokers > 20 cigarette/d and 20 nonsmokers) were also determined [median value of 790 ng/L (10.17 nmol/L) and 131 ng/L (1.70 nmol/L), respectively]. The 8-h time-weighted exposure intensity (Cl, micrograms/m3) of individual workers was monitored by means of charcoal tubes. The median value for exposure to benzene was 736 micrograms/m3 (9.42 mumol/m3) [geometric standard deviation (GSD) = 2.99; range 64 micrograms/m3 (0.82 mumol/m3) to 13,387 micrograms/m3) (171.30 mumol/m3)]. The following linear correlation was found between benzene concentrations in urine (Cu, ng/L) and benzene concentrations in the breathing zone (Cl, micrograms/m3): log(Cu) = 0.645 x log(Cl) + 1.399 r = .559, n = 110, p < .0001 With exclusion of workers who smoked from the study, the correlation between air benzene concentration and benzene measured in urine was: log(Cu) = 0.872 x log(Cl) + 0.6 r = .763, n = 63, p < .0001 The study results indicate that the urinary level of benzene is an indicator of occupational exposure to benzene.

Adult↗
PubMed1993

Methylene chloride exposure in industrial workers.

Methods of environmental and biological monitoring were applied in order to evaluate exposure to methylene chloride in workers operating in a factory where this substance was used as a solvent. For the measurement of methylene chloride in environmental concentration, the ambient air was sampled by using personal passive dosimeters. The activated charcoal was desorbed with CS2 and injected into a gas chromatograph connected with a mass spectrometer. The biological monitoring of exposed workers was performed by determining the concentration of CO in alveolar air (CA, ppm) and methylene chloride in urine (Cu, mu/L). Immediately after the end of the exposure, a urine sample was collected avoiding solvent loss and using gas-tight samplers. Excretion level in urine was determined by using headspace gas chromatography linked to a mass spectrometer. The CO was determined at the end of the shift by using a portable instrument. A group of 20 workers (12 smokers and 8 nonsmokers) in the manufacturing plant were monitored. No significant correlation was observed among the CO of all subjects and the concentration of methylene chloride in ambient air. When those workers who smoked were removed from the analysis, a correlation between the methylene chloride concentration in air and the CO concentration in alveolar air was found. Significant linear correlation was found between the environmental concentration of methylene chloride in the breathing zone and methylene chloride concentration in urine.

Adult↗
PubMed1993

Urinary styrene in the biological monitoring of styrene exposure.

The urinary excretion of styrene represents a promising indicator of exposure to this solvent. Nevertheless extensive research under field conditions is scant. In this investigation 214 styrene-exposed workers from 10 fiberglass-reinforced plastics factories were studied. Environmental monitoring was performed by personal passive sampling. Blood styrene and the urinary excretion of styrene and its main metabolites, mandelic acid (MA) and phenylglyoxylic acid (PGA), were measured. The correlation coefficient between the time-weighted average of environmental styrene and the mean urinary excretion of styrene was 0.88 (0.91 after logarithmic transformation), compared with the 0.82 and 0.78 of the end-of-shift MA and PGA values, respectively. A high correlation (0.86) was also found between styrene in the blood and urine. The results, obtained under field conditions with a large group of exposed workers, confirm the usefulness of the urinary excretion of styrene as an exposure index for the biological monitoring of styrene exposure.

Adolescent↗
PubMed1993

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 concentration, exposure times). These parameters are included in the equations showing the absorption and elimination indexes and lung clearances. The absorption and elimination indexes implied are discussed stressing their practical usefulness in the field of biological monitoring, industrial hygiene and in preventive medicine.

Absorption↗
PubMed1992

Serum albumin and others parameters in intravenous drug users HIV-infected.

In 37 intravenous drug users (IVDUs) in the first stages of HIV-infection (17 in stage II and 20 in stage III according to CDC), compared with 32 IVDUs HIV-negatives, we found a significant decrease in circulating leucocytes (p less than 0.01), lymphocytes (p less than 0.005), platelets (p less than 0.005), serum albumin (p less than 0.005), and C3 (p less than 0.02) and significant increase in serum gammaglobulins (p less than 0.0005) and IgG (p less than 0.0005). On the other hand no difference was observed in hemoglobin and in IgA levels; nevertheless an inverse relationship between serum IgA and CD4+ lymphocytes was present in HIV-positive (HIV+) patients (r = -0.34; p = 0.04). This observation agrees with that is observed in the advanced stages of HIV-infection, which presents an increase in IgA serum levels. In these stages this fact could be due to a decrease of secretory IgA, with a deficient barrier effect; the consequent recirculation of intestinal antigens should enhance the antibody production, as well as serum IgA. In the IVDUs HIV-infected a reverse correlation between albumin serum levels and the length of HIV-positivity (r = -0.44; p = 0.008) and a direct correlation between albumin serum levels and circulating CD4+ lymphocytes (r = 0.37; p = 0.05) were present. There was no direct linear relationship between albumin serum levels and creatinine, on the contrary to what was observed in the control group. The decrease of albumin levels could have a prognostic value as in other clinical conditions, in which it is associated with a higher mortality risk. Many factors could act to decrease albumin levels, but the most important one is perhaps the malnutrition of HIV-infected patients that can also be present in the first stages of infection, negatively influencing the associated immunodeficiency.

Adult↗
PubMed1991

Biological monitoring of the occupational exposure to halothane (fluothane) in operating room personnel.

The concentration of halothane (fluothane) in the ambient atmosphere was determined in five operating theaters of two hospitals in Italy. The concentrations of halothane in the ambient air exceeded the NIOSH recommended time-weighted average exposure levels (median value: 10.38 mg/m3). Halothane was detected in the urine of 58 exposed subjects (anesthetists, surgeons, and nurses). A significant correlation was found between the halothane concentration in urine produced during the shift (Cu, micrograms/L) and halothane environmental concentration (CI, mg/m3) (Cu = 0.242 x CI + 3.51) (N = 58; r = 0.92; p less than 0.0001). The results show that the urinary halothane concentration can be used as an appropriate biological exposure index. The biological values proposed are: 92 micrograms/L, corresponding to a 50 ppm of environmental exposure; 6.5 micrograms/L, corresponding to 2 ppm of environmental exposure and 3.9 micrograms/L, corresponding to a 0.5 ppm of environmental exposure.

Adult↗
PubMed1991

Acquired dyschromatopsia among styrene-exposed workers.

We investigated the occurrence of color vision loss in 75 styrene-exposed workers and in 60 referents. Color vision was evaluated by adopting the Lanthony D 15 desaturated panel, a test specifically suited to detect mild acquired dyschromatopsia. The results of the test were expressed as Color Confusion Index. Styrene exposure was evaluated with both environmental and biological monitoring. Airborne levels of the solvent were 3.2 to 549.5 mg/m3. In styrene-exposed workers color vision was significantly impaired when compared with referents matched for age. A significative correlation was found between environmental and urinary levels of styrene and Color Confusion Index excluding the influence of age in multiple regression analysis, indicating the possibility of a dose-effect relationship. The findings suggest that styrene can induce an early appearance of a dose-dependent color vision loss.

Adult↗