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Biomedical subjects

M Governa

Publications and source records attributed to M Governa.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1986

Impairment of human polymorphonuclear leukocyte chemotaxis by 2,5-hexanedione.

The effect of n-hexane metabolites on human polymorphonuclear leukocyte chemotaxis and luminol-dependent chemiluminescence was investigated. No effect was detected when 2-hexanol, 2-hexanone and gamma-valerolactone were used; 2,5-hexanedione at 75 micrograms/ml inhibited chemotaxis and a direct correlation between increasing the xenobiotic concentration and the degree of inhibition was found. Chemotactic peptide-induced chemiluminescence was not affected by 2,5-hexanedione. In order to clarify the phenomenon, plasma membrane fluidity was investigated by fluorescence polarization of the fluorescent probe trimethylammonium diphenylhexatriene. 2,5-hexanedione increased the membrane fluidity, while the other n-hexane metabolites did not change the degree of fluorescence polarization. Results suggest that the cellular functions modulated by membrane-cytoskeletal organization are affected by 2,5-hexanedione also at the low concentrations.

Chemotaxis↗
PubMed1986

Pulmonary alveolar lipoproteinosis in rats following intratracheal injection of pyrite particles.

Wistar rats were injected intratracheally with pyrite particles and after 6 and 12 mo, lungs were evaluated for histological changes. Results were compared with rats that were given particles of galena, lead silicate, travertine, and quartz. Under the light microscope no significant changes were observed in the lungs from animals treated with galena, lead silicate, and travertine. In the lungs from animals that received quartz, a typical nodular fibrosis was observed. Moreover, both pyrite-treated rats and quartz-treated rats developed pulmonary alveolar lipoproteinosis; the lesions were much less prominent and severe in animals injected with pyrite than with quartz. These results indicate that pyrite, like only a few other types of dust that are different from quartz, can evoke the development of pulmonary alveolar lipoproteinosis in rats.

Animals↗
PubMed1986

Silicotic lymph node lesions in non-occupationally exposed lung carcinoma patients.

The report deals with a series of peribronchial and mediastinal lymph node silicotic lesions, which were histologically and histochemically typical, in patients with bronchogenic cancer without any form of occupational dust exposure. The presence of a significant quantity of quartz was confirmed in the lesions by the use of backscatter electron imaging analysis, X-ray mapping and X-ray spectrometry. The lymph node lesions observed were actually silicotic in nature and had possible epidemiologic implications. There is a need for further investigations on larger series of cases to evaluate the incidence of the phenomenon and correlations between lung changes and lymph node lesions.

Adenocarcinoma↗
PubMed1985

[Analysis of electroneurographic data on a sample of normal subjects].

The ENGraphic basic data of 41 normal subjects were measured to determine a range of normal values and to analyze the importance of individual factors (gender, age, work). The work affects significantly the conduction velocities and the latencies more frequently than gender and age.

Adolescent↗
PubMed1985

[Modification of granulocyte chemotaxis during anesthesia for surgery].

The PMNs of fourteen patients undergoing general anesthesia for surgical operations were examined to determine whether abnormal chemotaxis occurs during these procedures. Neutrophil chemotaxis was determined immediately before anesthesia and after the anesthetic somministration. Anesthetic agents included 0.2-1% enflurane, 0.3-1% halothane or N20-02 (60:40). Neutrophil chemotaxis was reduced an average of 10.9% by fluorinated anesthetics, no significant modification (+8.1 +/- 13.0%) was detected by N20-02.

Adolescent↗