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M Governa

Publications and source records attributed to M Governa.

At least 19 recordsLinked to original sources
PubMed1994

Chemotactic activity of human polymorphonuclear leukocytes and industrial xenobiotics: a brief review.

This review deals with some of our contributions to the use of chemotaxis, as a tool in evaluating effects of industrial xenobiotics on PMN, either in vitro or ex vivo. In vitro experiments have shown that lead, arsenic, styrene and 2,5-hexanedione, a major neurotoxicant metabolite of n-hexane, reduce chemotaxis. The most important results of ex vivo experiments have confirmed those obtained in vitro with styrene and 2,5-hexanedione: a significant reduction of chemotaxis was indeed observed in PMN harvested from workers exposed to low levels of n-hexane or styrene who did not show any sign of biochemical or clinical alteration. After 3 weeks under non-exposed conditions, the chemotactic indexes were markedly increased in most of the workers which were exposed to styrene and in all the workers exposed to n-hexane, all of whom have shown a reduced chemotaxis at the first blood sampling. Moreover chemotaxis was found to be significantly reduced at relative low levels of lead: results of the in vitro and ex vivo experiments show a comparable ranking of midpoint inhibition concentrations. We are only at the dawn of the understanding of the relation between occupational xenobiotics and PMN chemotaxis. This research area is still promising for the future, since PMN chemotaxis seems to be adequate and it must therefore enter in well-defined study protocols for investigating the potential immunotoxicity of occupational chemicals to which humans are exposed at low levels.

Chemotaxis, Leukocyte↗
PubMed1994

Latex-induced asthma in four healthcare workers in a regional hospital.

Hypersensitivity to latex gloves has often been reported in patients who have undergone surgical treatment. Recent reports suggest that latex antigens can produce cutaneous and respiratory symptoms in workers occupationally exposed to latex. Four such cases of healthcare workers who were sensitized through exposure to latex have been observed. Two of these workers presented dermatitis as well as work-related respiratory symptoms, while the others only showed symptoms suggesting occupational asthma. The subjects were diagnosed as having latex hypersensitivity after skin prick-testing, and the immunoglobulin E serum level against latex gave positive results. In addition, changes in methacholine responsiveness also took place. In one case, an occupational exposure test was carried out which resulted in a 24% drop in the FEV1 value after 25 min of inhalation exposure. At least one year after the diagnosis, two nurses (subjects A and D) who had been removed completely from latex exposure experienced no further latex-induced symptoms. The other workers, who have continued working in the same laboratories using vinyl gloves, now display less severe symptoms but require regular anti-allergy treatment.

Adult↗
PubMed1994

Human polymorphonuclear leukocyte chemotaxis as a tool in detecting biological early effects in workers occupationally exposed to low levels of n-hexane.

Human polymorphonuclear leukocytes (PMN) were chosen to measure two cellular end points--chemotaxis and respiratory burst--and to verify whether they could function as biomarkers of early effect in detecting occupational exposure to n-hexane of apparently healthy shoe workers, without any electroneuromyographic (ENMG) abnormality. Chemotaxis, but not respiratory burst, was found to be impaired. A negative linear correlation between chemotaxis of PMN of those workers that had been exposed to n-hexane versus 2,5-hexanedione (2,5-HD) urinary concentrations were found. This negative trend is consistent with our previous in vitro experimental findings: it was observed that the progressive addition of 2,5-HD to PMN suspensions inhibited chemotaxis in a dose-dependent mode, while chemiluminescence was not modified. Now we have confirmed in vivo that chemotaxis is more sensitive than the respiratory burst response to 2,5-HD. Such results justify the interest in the behaviour of PMN harvested from workers exposed to n-hexane. Since significant inhibition of chemotactic activity was observed in some workers whose urinary 2,5-HD levels were lower than 5 mg l-1, which is the biological exposure index suggested by ACGIH, this study suggests that PMN chemotaxis may be proposed as a useful biomarker in detecting occupational exposure to low level of n-hexane.

Adolescent↗
PubMed1991

Effects of lead on polymorphonuclear leukocyte (PMN) functions in occupationally exposed workers.

Previous in vitro experiments have shown that lead can inhibit PMN chemotaxis, phagocytosis and superoxide formation. Moreover, we have observed an inhibition of PMN chemotaxis in workers occupationally exposed to lead with a mean blood lead concentration of 3.06 mumol/l. The present study was carried out to evaluate locomotion and luminol assisted chemiluminescence (CL) of polymorphonuclear leukocytes (PMN) harvested from ten lead occupationally exposed workers with blood lead concentrations of 1.59 mumol/l (SD 0.27 mumol/l). Since lipids affect PMN activity and lipid composition is modified in erythrocytes of lead workers, PMN lipids were also studied. Ten healthy male subjects of the same age were taken as controls. Chemotaxis, i.e. locomotion stimulated through a specific membrane receptor, was impaired in the PMN of lead workers, but random migration, i.e. unstimulated cell locomotion, and respiratory burst were both unmodified. Cholesterol and phospholipids were not changed, but the percentage of arachidonic acid was significantly increased. The release of LTB4, generated by the oxidative metabolism of arachidonic acid, was increased. CL, which detects reactive oxygen species (ROS), was unmodified, but this lack of change could be the result of an increase in ROS, due to the augmentated percentage of arachidonic acid, and of a decrease in ROS, due to a direct inhibitory effect of lead on ROS generation. On the basis of the results from these ex vivo experiments, the conclusion that chemotaxis is the PMN function primarily affected by lead was confirmed. PMN are considered to be one of the first cellular targets for the action of lead; low exposure to lead modifies their activity and mainly modifies chemotaxis and LTB4 production.

Adult↗
PubMed1990

Mortality rate and prognostic indices in 2615 burned patients.

Two thousand six hundred and fifteen burned patients are analysed according to mortality rate and the results are compared with other prognostic indices. Our statistical data are similar to those reported by Feller et al. (1976), but differ from those expected by Roi et al. (1983) and Bull (1971). It is suggested that other burns centres should produce their statistical figures in the same way, thereby producing a wider statistical experience and a more accurate prognostic index. The improvement in the survival rate in our centre in the past 5 years is also discussed.

Age Factors↗
PubMed1988

Increased membrane heterogeneity in stimulated human granulocytes.

TMA-DPH fluorescence decay in human PMN before and after stimulation with FMLP was studied using frequency domain fluorometry. Membrane heterogeneity was assessed by the width of the continuous distributions of lifetime values of Lorentzian shape used to describe the fluorescence decay. In non-stimulated granulocytes TMA-DPH fluorescence decay is characterized by two distributions of lifetime values centered at 6.5 and 1.0 ns and full width at half maximum of 0.3 and 1.2 ns, respectively. Within 15 min after stimulation, the center values of the two distribution components were 5.1 and 0.8 ns and the distribution width was 0.8 and 0.6 ns, respectively. These results indicate changes of membrane domain organization which can be ascribed to compositional changes and redistribution of membrane components.

Cell Membrane↗
PubMed1988

Impairment of chemotaxis of polymorphonuclear leukocytes from lead acid battery workers.

Since lead impairs in vitro the functions of macrophagic cells, we have studied the chemotactic activity of polymorphonuclear leukocytes (PMNs) obtained from lead acid battery workers who were removed from exposure one month before, because they had an abnormal lead absorption. Controls were 18 age matched subjects without any history of occupational lead exposure. Both lead acid battery workers and controls had no alterations of the blood haematological and metabolic parameters. Chemotaxis was carried on in Boyden chambers using zymosan activated serum as chemotactic stimulus. The chemotactic indexes are 56.4 +/- 8.7 in acid battery workers and 75.6 +/- in controls. The difference, which is statistically significant, shows that lead workers have an impairment of PMNs chemotactic activity.

Adult↗
PubMed1988

Activation of the alternative complement pathway and generation of stimulating factors for granulocytes by glass fibers.

Continuous-filament glass fibers coated with organic agents, candidate asbestos substitutes, were assessed for their ability to elicit from normal human serum complement-derived cleavage products which are able to stimulate the chemotaxis and the respiratory burst of polymorphonuclear leukocytes. Glass fibers generated chemoattracting and respiratory stimulating factors for polymorphonuclears from human serum. The effect was dose related for chemotaxis from the serum fiber concentration of 75 micrograms/ml to 1,250 micrograms/ml. The serum chemoattracting activity, as well the respiratory stimulation, were dramatically impaired when serum had been preliminarily absorbed with antiC5 antiserum. Since the impairment of chemotactic activity occurred also in the presence of EDTA, but not in the presence of EGTA, we assumed an activation of the alternative complement pathway. Glass fibers were studied in comparison to a UICC sample of Canadian chrysotile asbestos, which is able to activate in vitro the alternative complement pathway. Glass fibers exhibited less ability than asbestos fibers to generate complement cleavage products with chemotactic activity for polymorphonuclears; however, they produced an activity about equal to 80% of a chemotactic standard stimulus such as zymosan-activated plasma.

Asbestos↗
PubMed1988

Increased neutrophil leukocyte chemotaxis induced by release of a serum factor in toluene-diisocyanate (TDI) asthma.

The activation of blood neutrophil leukocytes has been proven in subjects with IgE-mediated and non-IgE-mediated asthma. This event appears to be modulated by the release of humoral factors. We submitted 12 toluene-diisocyanate (TDI) asthmatic workers to TDI provocation. During the late asthmatic reaction there was release of a serum chemoattracting factor for normal neutrophil leukocytes and activation of asthmatic neutrophil leukocytes. This appears to be the first demonstration of neutrophil chemotactic activity liberated during the late TDI reaction in humans. The results are explained by an acute inflammatory process occurring during the late asthmatic reaction induced by TDI.

Adult↗
PubMed1987

In vitro impairment of human granulocyte functions by lead.

Chemotaxis and receptor independent phagocytosis of human polymorphonuclear leukocytes (PMNs) exposed to lead in vitro (concentrations between 1.2 microM and 115 microM) were studied. Chemotaxis was measured in Boyden chambers and phagocytosis was investigated using latex beads. Additional methods were also applied. Superoxide anion formation from PMNs activated with preopsonized zymosan was quantified as superoxide dismutase-inhibitable reduction of ferricytochrome c. Steady state fluorescence polarization was performed using trimethylammonium diphenylexatriene (TMA-DPH). Lead concentrations were highly correlated both with decreased chemotactic activity (r = 0.70 p less than 0.01) and with decreased phagocytosis (r = 0.68 p less than 0.01). Ferricytochrome c reduction was not significantly affected. An increase in fluorescence polarization was recorded at the highest concentration of lead used, i.e. 57.6 microM and 115 microM, both in unstimulated PMNs and in PMNs activated with N-formyl-methionyl-leucyl-phenylalanine chemotactic peptide (n-FMLP). Moreover, an increase in the fluorescence polarization was observed in PMNs pretreated with a microtubule disrupting drug, exposed to lead concentrations of 14.4 microM and 57.6 microM and then activated with n-FMLP; no increase was recorded at the lowest lead concentrations used, i.e. 1.2 microM and 3.6 microM. The possible interaction of lead with the membrane-cytoskeleton apparatus is discussed.

Adult↗
PubMed1987

Autoantibodies in 16 patients with extensive burns and a review of the literature.

Serum samples were taken during the first 3 weeks and 1 year after discharge from hospital of 16 patients with burns covering more than 35 per cent of the body surface area. The sera were tested for the presence of antinuclear, antimitochondrial, anti smooth muscle, anti brush border and anti gastric parietal cell autoantibodies using the technique of indirect immunofluorescence. Compared with measurements for the same autoantibodies, in sera from 25 healthy blood donors, the burned patients' sera showed the presence of anti smooth muscle autoantibodies in 81.2 per cent, anti brush border autoantibodies in 56.2 per cent, antimitochondrial autoantibodies in 31.2 per cent and antinuclear autoantibodies in 12.5 per cent of the sera. Autoantibodies to gastric parietal cells were not detected. A correlation was noted between the presence of antimitochondrial autoantibodies and alterations in liver function. In contrast, no correlations were found between the raised levels of the various autoantibodies and resuscitative fluid or antibiotic therapy, intercurrent infections, serum immunoglobulin levels, surgical treatment or the duration of stay in hospital. The high titre of autoantibodies to anti smooth muscle could have arisen from tissue protein degradation associated with the raised requirements for energy by the hypermetabolic patients.

Adult↗
PubMed1987

Urinary excretion of 2,5-hexanedione and peripheral polyneuropathies workers exposed to hexane.

Forty shoe factory workers who were exposed to hexane were investigated to see if there was a correlation between electroneuromyographic changes indicative of neuropathy and urinary excretion of 2,5-hexanedione. Urinary samples were analyzed for the presence of the metabolic products of n-hexane and its isomers. Electrodiagnostic examination was carried out following the urinary sampling. A rating scale was used to obtain a cumulative numeric index of electrodiagnostic findings. 2,5-Hexanedione and gamma-valerolactone were discovered in all cases, while 2-hexanol was found in 11 cases. 2,5-Hexanedione was the main metabolite in most cases (39 of 40). Only in 1 case was a low level of 2-methyl-2-pentanol detected; 3-methyl-2-pentanol was never detected. Metabolic products of cyclohexane were present in about one-fifth of the cases, while trichloroethanol, a metabolic product of trichoroethylene, was nearly always present, all at very low concentrations. Electromyographic abnormalities significant for early detection of toxic polyneuropathy were found in 14 cases. A statistically significant correlation of the electroneuromyographic scoring on the urinary concentrations of measured metabolites was observed only with 2,5-hexanedione and gamma-valerolactone, both derived from n-hexane. Since gamma-valerolactone is probably not a true metabolite of n-hexane, our results support the hypothesis that polyneuropathies in shoemakers are due to 2,5-hexanedione. For practical purposes the urinary concentration of 2,5-hexanedione can serve as a predictive measurement for early detection of neurotoxic lesions at preclinical states.

Adolescent↗
PubMed1987

Ventilatory function in rubber processing workers: acute changes over the workshift.

When considering rubber tyre manufacturing from an occupational health viewpoint, three areas may be identified in which exposure to respirable materials are potentially harmful: the processing, curing, and talc areas. A study of the ventilatory function of the entire work force employed in the processing area in a rubber tyre manufacturing plant was undertaken to determine whether an acute reduction in lung function occurs over the course of their working shift (the plant worked a three shift system) and whether a chronic exposure to the occupational airborne contaminants causes permanent changes in lung function. The ventilatory function was measured at the worksite at the beginning and immediately after the end of the workshift. No evidence of chronic obstructive pulmonary disease was found and in most cases no significant decline in FEV1 was observed. Only one of the 79 individuals showed a moderate obstruction, measured by the ratio FEV1/FVC which gave the value of 0.55, with no variation over the shift. For non-smokers, the FVC, FEV1, and FEF25-75% were lower in those exposed for more than five years than in those exposed for five years or less. A similar pattern was also observed in the FVC and FEV1 of the smokers. None of these differences was statistically significant. Within each exposure group the pulmonary function of the smokers was lower than that of the non-smokers, but the only significant difference was found in the values of FEF25-75%. Only one man showed a decline in the FEV1/FVC ratio over the shift, but during each shift, a decrease in all the lung function tests was observed. The decrease was smallest during the first of the three shifts. These results are thought to support the hypothesis that there are acute adverse effects over an eight hour shift. Further investigations are needed to discover whether these acute changes in lung function result from a chemical stimulation or irritant receptors in the airways.

Adult↗
PubMed1986

Changes of membrane fluidity in chemotactic peptide-stimulated polymorphonuclear leukocytes.

Although the phenomenon of stimulus-response coupling in polymorphonuclear leukocytes involves a series of membrane events the influence of stimulation on membrane fluidity is to clarify. In our experiments we have used 1-(4-trimethylaminophenyl) 6-phenyl-1,3,5-hexatriene and 1,6-diphenyl-1,3,5-hexatriene fluorescence polarization technique to evaluate membrane fluidity in living polymorphonuclear leukocytes after stimulation with N-formyl-methyonil-leucyl-phenylalanine peptide which has a well defined membrane receptor on the plasma membrane. We report that polymorphonuclear leukocytes stimulation increases 1-(4-trimethylaminophenyl)-6-phenyl-1,3,5-hexatriene polarization, only when colcemid, a microtubule disrupting drug, is added to polymorphonuclear leukocytes. This can be viewed as an indirect evidence that microtubules are involved in the control of polymorphonuclear leukocytes membrane fluidity. On the contrary no changes have been observed with 1,6-diphenyl-1,3,5-hexatriene. This study indicates the potential use of 1-(4-trimethylaminophenyl)-6-phenyl-1,3,5-hexatriene to evaluate the involvement of plasma membrane physical state during intact cell activity.

Cell Membrane↗