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Biomedical subjects

M Valentino

Publications and source records attributed to M Valentino.

At least 73 records · Page 4Linked to original sources
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

[Hyperlipidemia findings in workers in an oil refinery].

During a cross sectional epidemiologic study the cholesterol and triglyceride plasmatic levels were measured in 207 workers employed in an oil refinery. Our results show high levels both for cholesterol and triglyceride. Emphasis has been laid on the serious dietary and hygienic problems for these workers. The finding of hyperlipidemia as well as obesity and over-weight do not seem to be related to exposure to any occupational chemical hazard.

Adult↗
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↗
PubMed1982

Effect of lead on physical state of erythrocytes and model membranes.

Lead has an high affinity for erythrocyte and influences the membrane bound enzymes activities but its interactions with biological membranes is still unclear. We have investigated the effect of lead as free ion on physical state of erythrocytes and liposomes by Electron Spin Resonance (ESR) using two spin labels 5-doxyl-stearate (5-NS) and 16-doxyl-stearate (16-NS) and by DPH (1,6-diphenyl-1,3,5-hexatriene) fluorescence polarization analysis. Lead induces decrease of fluidity in natural membrane which is more evident in membrane hydrophobic core; the effect is not correlated with lead concentration. Lead ion interacts with negative charged liposomes inducing an increase of their microviscosity.

Cardiolipins↗
PubMed1982

Changes of membrane fluidity in erythrocytes of lead-exposed workers.

We have studied the effect of lead on the fluidity of erythrocyte membrane to clarify if lead can interact in vivo with biological membranes. Erythrocyte membranes were chosen in our study because a decrease of red cell osmotic fragility is also evident in the absence of laboratory and clinical signs of anaemia. The study was undertaken using the Electron Spin Resonance technique with two spin labels 5-doxyl stearate and 16-doxyl-stearate, which probe the physical state of the polar surface and the inner core of the membrane respectively. Red blood cells and erythrocyte ghosts were prepared from the blood of workers occupationally exposed to lead and from healthy controls. The determinations of Pb blood, Pb urine, urine coproporphyrin and delta-aminolevulinic acid showed an increased internal dose of lead, but the ordinary metabolic and haematological parameters were in the normal range. Our results show that in lead workers there is a change in chemical physical state both in erythrocytes and erythrocyte ghosts consistent with a decrease of membrane fluidity, which is evident in the surface as well as in the inner core of the membrane. The degree of membrane fluidity modification does not appear correlated with blood lead level. Changes in the membrane structural organization could be the molecular basis of some pathological alterations induced by lead.

Adult↗
PubMed1982

[Adsorption of proteins by artificial mineral fibers: in vitro experiments].

Since previous studies reported that in vitro some proteins and phospholipids were absorbed by asbestos fibres, namely chrysotile, in this study, man made filamentous glass fibers are been tested in vitro at the presence of proteins. The objective was to obtain evidence to evaluate whether continuous glass fibers have a behaviour similar to asbestos fibres. A sample of chrysotile fibres was used as control. Uptake of bovine serum albumin and horse spleen ferritin on these continuous glass fibres has been observed. However on glass fibres adsorbed less proteins per weight unit (22 mg/g and 12 mg/g respectively for albumin and ferritin) than asbestos chrysotile fibres (42 mg/g and 49 mg/g respectively for albumin and ferritin).

Adsorption↗
PubMedDate not supplied

Reversibility of thymulin production impairment by L-arginine supplementation in mice exposed to inorganic mercury.

Immunotoxicological effects fo mercury on peripheral immune system are known. We had previously in vitro found that mercuric chloride inhibits thymulin production in mouse thymus cultures at concentrations as low as 10(-8) M. In this study, thymus efficiency, assessed as production of active and total thymulin, was evaluated in vivo using young mice that were injected sc every 3 days for 4 weeks with saline containing mercuric chloride at different concentrations (0 -controls-, 0.001 or 1.0 mg HgCl2/kg body weight). The results show that both the doses are able to cause a significant reduction in active and total thymulin production. Since arginine enhances immune efficiency some of the animals also received a diet supplemented with arginine in order to evaluate a possible role of arginine during mercury intoxication. The data show that arginine has a protective effect on thymic endocrine efficiency. Mice, treated with the lowest dose of mercury and receiving and arginine supplemented diet, produced active and total thymulin like mercury untreated mice. Arginine is an aminoacid which may be found in various amounts in different foods, some foods are particularly rich in arginine i.e. peanuts, stock fish. We suggest that the daily arginine intake may account for individual susceptibility to the mercury-induced immunological effects which are found in mercury occupationally exposed workers.

Animals↗
PubMedDate not supplied

[Course of isocyanate-induced asthma in relation to exposure cessation: longitudinal study of 50 subjects].

Isocyanates, particularly Toluene Diisocyanate (TDI), have been the most common cause of occupational asthma for decades. Fifty workers with a diagnosis of isocyanate-induced asthma were followed up for a mean period of 8.4 years. Pulmonary function testing for FVC and FEV1, allergological tests, nonspecific bronchial challenge to methacholine and specific bronchial challenge to isocyanates were performed at the time of diagnosis and during follow-up. Data on symptoms and drug response were rated on a scale. Patients were subdivided into two groups based on persistence of (A; 13 patients) or removal from (B; 37 patients) isocyanate exposure. There were no significant differences in any characteristic between the two groups at the time of diagnosis. At follow-up, group B subjects showed significant improvement in symptoms, consequent reduction in use of medications and increase in PD20. None worsened, sixteen (43.3%) remained stable, twelve (32.4%) improved and nine (24.3%) became asymptomatic. The latter subjects were generally younger, they had shorter duration of symptoms and exposure to the agents, and longer removal from exposure, although none of these differences was significant. In 67% of cases they had an immediate reaction to TDI challenge. By contrast, the condition of group A patients deteriorated significantly during the follow-up period in terms of symptoms, pulmonary function parameters, PD20 and use of medications. Overall, seven subjects (53.8%) worsened during follow-up and none improved. Group B subjects were further divided into subgroups B1 and B2 based on duration of removal from exposure: B1 < 10 years, B2 > or = 10 years. There were no significant differences between the two subgroups, even though PD20 was higher in B2. The present study confirms that early diagnosis and immediate removal from exposure are crucial, though not always sufficient, for a favourable evolution of the disease.

Adult↗
PubMedDate not supplied

[VATS resection of peripheral pulmonary nodules following CT-guided cytologic assessment].

In a thorax surgery domain the V.A.T.S. is the important new treatment for particular thorax diseases. authors would like to show the advantages using V.A.T.S. for the therapy of peripheric lung nodules, also using a CT-guided extemporary cytologic tipization. The CT-guided biopsy and then an extemporary cytologic tipization, represent the first steps for lung nodules candidated to the V.A.T.S. These lesions have got singular aspects: benign lesions, methastasts, specific and unknown lesions. In that way traditional surgery is for primitive lung neoplasm in order to have a certain oncologic solution and because it is possible to test the complication of large resection. The CT-guided cytologic tipization can be done by a particular kit invented from the authors: a flessible needle works like an anchor and is a good repair of a nodule in order to proceed with V.A.T.S. This method has been utilized for 45 patients with good results.

Biopsy, Needle↗
PubMedDate not supplied

[Rhizarthrosis of the thumb in ironing workers].

BACKGROUND: Rhizarthrosis of the hand secondary to job-related static-dynamic stress is a rare occupational condition characterised by secondary osteoarthrosis. OBJECTIVES: We report 5 clinical cases of female ironers employed in small-scale laundries, who after more than 10 years on the job developed pain in the right thumb. Disease onset may have been favoured by the continuous functional stress exerted on the joint. METHODS: Clinical examination, hand X-rays and ultrasonography of the trapezio-metacarpal joint led to the diagnosis of rhizarthrosis. The electromyographic and biomechanical analysis of work tasks was conducted by simulating normal ironing activity. RESULTS: Patient history and electromyographic and biomechanical data showed a close causal relationship between age, job and diagnosis. CONCLUSIONS: In the case of workers over 50 years of age whose jobs have the characteristics described here, Finkelstein's test should be performed on occasion of occupational health surveillance to screen for the arising of the disease.

Female↗
PubMedDate not supplied

[Biological response to diverse polymorphic forms of silica].

Under two different experimental conditions (cleavage of C5 complement fraction and human endothelial cells cultures), crystalline and amorphous silica samples were tested. Different biological reactions were achieved.

Cells, Cultured↗
PubMedDate not supplied

[Increase of TNF-alpha in subjects occupationally exposed to lead].

Occupational exposure at low doses of lead induces a significant increase of TNF-alpha plasma levels. Recently has been showed the crucial role on atherosclerosis origin of this pro-inflammatory cytokine. It is assumable a contribution of lead in atherosclerosis course in exposed subjects.

Adult↗
PubMedDate not supplied

[Noise-related occupational risk aboard fishing vessels: considerations on prevention and the protection of exposed workers].

Recent legislation regarding the safety of workers aboard fishing vessels requires the appointment by ship owners of a Reference Physician in charge of health surveillance, preventive inspections and related tasks. As maritime workers, especially fishermen, have always been excluded from legal protection of occupational health, there are no exhaustive data on the incidence of their occupational disease. Several epidemiological studies of fishermen have evidenced a high prevalence and incidence of occupational conditions, among which noise-related hypoacousia. We report data of a phonometric survey conducted aboard six fishing vessels carrying a crew of less than six fishing in the mid-Adriatic. Measurements were performed during fishing and navigation aboard five vessels fitted with a fixed-pitch propeller and during fishing only aboard one vessel fitted with an controllable pitch propeller. Measurements were conducted: 1) in the engine rooms; 2) in the work area on deck; 3) at the winch; 4) in the wheelhouse; 5) in the mess-room and kitchen; 6) in the sleeping quarters. Results show that the equivalent sound pressure level in the engine rooms consistently exceeded 90 dBA on all vessels. The speed of the vessels fitted with the fixed-pitch propeller is 3-4 knots in the fishing phase and around 10 knots during navigation to and from the fishing grounds; noise emission is lower with the former regimen because of the smaller number of engine revolutions per minute. Our survey demonstrated considerably different noise levels in the various areas of vessels. One key element in workers' exposure, the tasks assigned and the environmental working conditions is of course the type of fishing in which the vessel is engaged. Further phonometric studies are required to assess the daily level of exposure per crew member, which represents the reference for the noise-related risk of each subject. Knowledge of the sound pressure levels in the work environment and the length of daily exposure of each crew member will allow to assess the level of occupational exposure and consequently enact the proper prevention and protection measures by the Reference Physician.

Fisheries↗